The document discusses the NNPDF3.1 global analysis of parton distribution functions (PDFs). It provides an update to NNPDF3.0 motivated by new high-precision collider data and progress in NNLO calculations. NNPDF3.1 fits both a perturbative and fitted charm PDF and finds slightly better fit quality for the fitted charm case. Comparisons to NNPDF3.0 show agreement within uncertainties and reduced PDF errors in NNPDF3.1 due to the new LHC data.
The document summarizes the NNPDF3.1 global analysis which provides an updated determination of parton distribution functions (PDFs) from experimental data. Key points include:
1) NNPDF3.1 includes new high-precision measurements from the LHC as well as NNLO QCD calculations, allowing more data to be included. It also fits the charm PDF rather than assuming it is purely perturbative.
2) The new data provides stronger constraints on PDFs, particularly the gluon and down quark, significantly reducing their uncertainties. It also shows good agreement with the previous NNPDF3.0 analysis.
3) For the first time, NNPDF3.1 includes LHC
The impact of new collider data into the NNPDF global analysisJuan Rojo
The document summarizes Juan Rojo's presentation on the impact of new collider data in the NNPDF global analysis. It discusses updates and improvements to the NNPDF methodology, including adopting the public code APFEL, adding new LHC datasets like LHCb and top quark pair differential distributions, and analyzing the impact on parton distributions from including precise Tevatron and LHC Z boson data. Preliminary results from NNPDF3.1 indicate good stability compared to the previous NNPDF3.0 analysis, with reduced uncertainties and improved flavor separation from new experimental inputs.
NNPDF3.0: Next Generation Parton Distributions for the LHC Run IIjuanrojochacon
NNPDF3.0 is a new PDF release from the NNPDF collaboration that incorporates recent experimental data from HERA and the LHC, improved theory calculations, and methodological advances. Key aspects of NNPDF3.0 include the inclusion of new data like HERA structure functions, LHC jets and electroweak data, and top quark production data. It also utilizes approximate NNLO calculations for jets and NLO electroweak corrections for Drell-Yan production. The fitting methodology has been improved with a C++ rewrite of the code and validation on closure tests. Preliminary results show good agreement with NNPDF2.3 and reduced uncertainties for some PDFs from the new data and methodology
Neural Network Fits of Parton DistributionsJuan Rojo
The document discusses neural network fits of parton distribution functions (PDFs). It describes the NNPDF approach, which uses artificial neural networks as universal interpolators to parametrize PDFs without theoretical bias, in contrast to traditional approaches. The NNPDF method also uses a Monte Carlo replica method to estimate PDF uncertainties without linear approximations. Recent NNPDF results include determinations of PDFs including quantum electrodynamics corrections and an investigation of the intrinsic charm content of the proton.
QCD at the LHC: recent progress and open problemsjuanrojochacon
The document discusses recent progress and open problems in QCD at the LHC. It notes that improving the quantitative understanding of the Standard Model is essential, and that sharpening QCD tools could enable new discoveries at the LHC. In particular, better parton distribution functions, higher-order perturbative calculations, and matching calculations to parton showers are highlighted as important for improving both precision and sensitivity to new physics. The talk outlines the current status and future prospects for parton distribution functions, fixed-order calculations up to NNLO, matching to parton showers, and merging samples with different jet multiplicities.
Parton distributions in the LHC precision erajuanrojochacon
This document summarizes Juan Rojo's presentation on parton distribution functions (PDFs) at the Zurich Phenomenology Workshop 2018. The key points are:
1) PDF fits require combining perturbative cross-sections calculated using the Standard Model Lagrangian with non-perturbative PDFs extracted from a global analysis of experimental data.
2) More precise PDFs are needed to reduce uncertainties on calculations of processes like Higgs production and measurements of its couplings at the LHC.
3) Recent PDF analyses have included new data like differential top quark production from LHC and NNLO calculations, improving determinations of the gluon PDF over a wide range of x values.
4) Small-x data
Parton distributions with QED corrections and LHC phenomenologyjuanrojochacon
The document discusses parton distribution functions (PDFs) that include quantum electrodynamics (QED) corrections. It summarizes the NNPDF2.3QED PDF set, which is the first to include next-to-next-to-leading order (NNLO) QCD and leading order (LO) QED effects. The photon PDF is directly constrained by LHC data for the first time. The PDF set improves constraints on the photon PDF from both DIS and LHC Drell-Yan data. It also discusses implications for LHC phenomenology from photon-initiated contributions.
Parton Distributions and the search for New Physics at the LHCjuanrojochacon
Juan Rojo gave a seminar at King's College London on September 23, 2015 about parton distribution functions (PDFs) and their importance for precision physics at the Large Hadron Collider (LHC). PDFs describe the momentum distributions of quarks and gluons within protons and are crucial for determining cross sections and uncertainties for many LHC processes. The accurate determination of PDFs requires global analyses of experimental data using flexible parametrizations like neural networks to avoid biases. PDF uncertainties now limit characterization of the Higgs boson and searches for new physics at the LHC.
The document summarizes the NNPDF3.1 global analysis which provides an updated determination of parton distribution functions (PDFs) from experimental data. Key points include:
1) NNPDF3.1 includes new high-precision measurements from the LHC as well as NNLO QCD calculations, allowing more data to be included. It also fits the charm PDF rather than assuming it is purely perturbative.
2) The new data provides stronger constraints on PDFs, particularly the gluon and down quark, significantly reducing their uncertainties. It also shows good agreement with the previous NNPDF3.0 analysis.
3) For the first time, NNPDF3.1 includes LHC
The impact of new collider data into the NNPDF global analysisJuan Rojo
The document summarizes Juan Rojo's presentation on the impact of new collider data in the NNPDF global analysis. It discusses updates and improvements to the NNPDF methodology, including adopting the public code APFEL, adding new LHC datasets like LHCb and top quark pair differential distributions, and analyzing the impact on parton distributions from including precise Tevatron and LHC Z boson data. Preliminary results from NNPDF3.1 indicate good stability compared to the previous NNPDF3.0 analysis, with reduced uncertainties and improved flavor separation from new experimental inputs.
NNPDF3.0: Next Generation Parton Distributions for the LHC Run IIjuanrojochacon
NNPDF3.0 is a new PDF release from the NNPDF collaboration that incorporates recent experimental data from HERA and the LHC, improved theory calculations, and methodological advances. Key aspects of NNPDF3.0 include the inclusion of new data like HERA structure functions, LHC jets and electroweak data, and top quark production data. It also utilizes approximate NNLO calculations for jets and NLO electroweak corrections for Drell-Yan production. The fitting methodology has been improved with a C++ rewrite of the code and validation on closure tests. Preliminary results show good agreement with NNPDF2.3 and reduced uncertainties for some PDFs from the new data and methodology
Neural Network Fits of Parton DistributionsJuan Rojo
The document discusses neural network fits of parton distribution functions (PDFs). It describes the NNPDF approach, which uses artificial neural networks as universal interpolators to parametrize PDFs without theoretical bias, in contrast to traditional approaches. The NNPDF method also uses a Monte Carlo replica method to estimate PDF uncertainties without linear approximations. Recent NNPDF results include determinations of PDFs including quantum electrodynamics corrections and an investigation of the intrinsic charm content of the proton.
QCD at the LHC: recent progress and open problemsjuanrojochacon
The document discusses recent progress and open problems in QCD at the LHC. It notes that improving the quantitative understanding of the Standard Model is essential, and that sharpening QCD tools could enable new discoveries at the LHC. In particular, better parton distribution functions, higher-order perturbative calculations, and matching calculations to parton showers are highlighted as important for improving both precision and sensitivity to new physics. The talk outlines the current status and future prospects for parton distribution functions, fixed-order calculations up to NNLO, matching to parton showers, and merging samples with different jet multiplicities.
Parton distributions in the LHC precision erajuanrojochacon
This document summarizes Juan Rojo's presentation on parton distribution functions (PDFs) at the Zurich Phenomenology Workshop 2018. The key points are:
1) PDF fits require combining perturbative cross-sections calculated using the Standard Model Lagrangian with non-perturbative PDFs extracted from a global analysis of experimental data.
2) More precise PDFs are needed to reduce uncertainties on calculations of processes like Higgs production and measurements of its couplings at the LHC.
3) Recent PDF analyses have included new data like differential top quark production from LHC and NNLO calculations, improving determinations of the gluon PDF over a wide range of x values.
4) Small-x data
Parton distributions with QED corrections and LHC phenomenologyjuanrojochacon
The document discusses parton distribution functions (PDFs) that include quantum electrodynamics (QED) corrections. It summarizes the NNPDF2.3QED PDF set, which is the first to include next-to-next-to-leading order (NNLO) QCD and leading order (LO) QED effects. The photon PDF is directly constrained by LHC data for the first time. The PDF set improves constraints on the photon PDF from both DIS and LHC Drell-Yan data. It also discusses implications for LHC phenomenology from photon-initiated contributions.
Parton Distributions and the search for New Physics at the LHCjuanrojochacon
Juan Rojo gave a seminar at King's College London on September 23, 2015 about parton distribution functions (PDFs) and their importance for precision physics at the Large Hadron Collider (LHC). PDFs describe the momentum distributions of quarks and gluons within protons and are crucial for determining cross sections and uncertainties for many LHC processes. The accurate determination of PDFs requires global analyses of experimental data using flexible parametrizations like neural networks to avoid biases. PDF uncertainties now limit characterization of the Higgs boson and searches for new physics at the LHC.
Parton Distributions and Standard Model Physics at the LHCjuanrojochacon
This document discusses parton distribution functions (PDFs) and recent developments. It notes that NNLO calculations are essential to reduce uncertainties in PDF analysis. Several key processes like inclusive jet production and top quark production are now available at NNLO. The document also discusses the inclusion of LHC data like W+charm, top quark, and jet data in global PDF fits. It highlights updates to various PDF fitting groups and the upcoming NNPDF3.0 release.
NNLO PDF fits with top-quark pair differential distributionsJuan Rojo
Juan Rojo presented a study on including top-quark pair differential distributions in NNLO global PDF fits. The distributions provide stringent constraints on the large-x gluon, comparable to inclusive jet data. Fitting normalized distributions and including one distribution from ATLAS and CMS improves the description of data and reduces PDF uncertainties, particularly at high masses important for BSM searches. Some tension is seen between ATLAS and CMS measurements that can be reduced by fitting the experiments separately. Differential top data will be essential for future global PDF fits.
Guide for visualizing JMA's GSM outputs using GrADSJMA_447
The document discusses visualizing JMA high-resolution GSM data with GrADS. It provides an overview of the JMA data service that provides GRIB2 forecast data. It then discusses preparing the data for visualization with GrADS, including using tools to create control and index files from GRIB2 data. Finally, it covers basic interactive operation and customization of images using GrADS.
Recent progress in proton and nuclear PDFs at small-xjuanrojochacon
1) The document discusses recent progress in proton and nuclear parton distribution functions (PDFs) at small values of x. PDFs describe the momentum distribution of quarks and gluons inside protons and nuclei.
2) Global analyses of experimental data from various processes are used to determine PDFs at hadronic scales, which are then evolved perturbatively to higher scales relevant for LHC predictions. Recent analyses include data from the LHC.
3) Probing PDFs at small x requires processes dominated by gluons at leading order, produced in the forward region with low invariant masses. Examples discussed are direct photon and charm production. LHCb and future forward calorimeter data provide constraints on the small-
PDFs at the LHC: Lessons from Run I and preparation for Run IIjuanrojochacon
This document summarizes parton distribution functions (PDFs) at the start of LHC Run II. It discusses the status of recent PDF sets from NNPDF, MMHT, CT, ABM, and HERAPDF. It notes some differences between these sets and the importance of PDF uncertainties for LHC measurements. The document also discusses benchmarks between PDF sets, comparisons using the APFEL online tool, and the prospects for including more ATLAS data in global PDF fits to further constrain PDFs.
Real-Time Pedestrian Detection Using Apache Storm in a Distributed Environment csandit
This document discusses real-time pedestrian detection using Apache Storm in a distributed environment. It proposes a methodology that distributes video frames across multiple nodes ("bolts") for parallel processing. Each bolt detects pedestrians in a different region of the frame. Only detection results, not full frames, are transmitted to reduce overhead. The methodology is implemented using Apache Storm and evaluated on a test system with improved processing speed. Pedestrian detection has applications in safety and analytics.
New dynamics in parton distributions at a 100 TeV hadron colliderjuanrojochacon
This document discusses parton distribution functions (PDFs) relevant for a future 100 TeV hadron collider. It summarizes that such a collider would probe PDFs at smaller x values than currently possible, down to x=10-9. It would also probe higher mass scales, up to masses of 10 TeV. Current PDF determinations have little constraint for x<10-4 or masses above 1 TeV. The increased energy would require considering effects like top quark PDFs, electroweak corrections, and high-energy resummation not important at lower energies. Polarized collisions could also provide insights into PDFs.
This document outlines José Cupertino Ruiz Vargas's PhD thesis on searching for diboson resonances in CMS data. It begins with an introduction to the standard model of particle physics and motivations for physics beyond the standard model, including the Randall-Sundrum model with extra dimensions. It then describes the CMS detector and object identification techniques. The analysis strategy is to select events with two opposite-sign leptons and two jets, and estimate backgrounds using Monte Carlo simulations and data-driven techniques. Unblinded results show agreement between data and background predictions in control regions.
This document discusses heaps and their use in implementing priority queues. It describes how a max-heap or min-heap is a complete binary tree that satisfies the heap property, where each internal node is greater than or equal to its children. It explains how a heap can be represented using a simple array and how to build a heap from an unsorted array in O(n) time by sifting nodes down. Deleting the root element and maintaining the heap property takes O(log n) time. Heap sort uses a heap to sort an array in O(n log n) time. Priority queues can be efficiently implemented using max-heaps.
Parton Distributions: future needs, and the role of the High-Luminosity LHCjuanrojochacon
1) Improved PDFs are needed to match the accuracy of higher-order calculations of cross sections and characterize properties of the Higgs boson and search for new physics.
2) The HL-LHC could significantly reduce PDF uncertainties through high-statistics measurements, especially in processes sensitive to large-x gluons and quarks like top quark pair production and Drell-Yan.
3) Preliminary studies generating HL-LHC pseudo-data show PDF uncertainties on the gluon-gluon and quark-antiquark luminosities could be reduced by 10-30% from top pair and Drell-Yan measurements respectively.
This document summarizes an internship project using the WRF-ARW model to simulate a tropical cyclone. The internship involved learning UNIX, WRF installation, configuration and running a simulation of Tropical Cyclone HudHud without data assimilation. The results showed the model predicted the cyclone track closely compared to observations. Future work proposed using more cyclones and assimilating Doppler radar data to evaluate impact on track and intensity forecasts. The internship provided valuable experience in operational forecasting and research using numerical weather prediction models.
NNPDF3.0: parton distributions for the LHC Run IIjuanrojochacon
NNPDF3.0 is a new PDF determination that includes updated data and theory improvements compared to NNPDF2.3. It includes all HERA-II data and new LHC measurements. The fitting code was rewritten in C++ and validated using closure tests. NNPDF3.0 shows reasonable agreement with NNPDF2.3 while improving descriptions of data and reducing uncertainties in some regions. It provides PDFs for use at the LHC Run II.
Constraints on the gluon PDF from top quark differential distributions at NNLOjuanrojochacon
- The document discusses constraints on the gluon PDF from top quark production at hadron colliders.
- It describes using the inclusive top quark pair production cross section to reduce uncertainties in the gluon PDF, especially in the large-x region between 0.1 and 0.5.
- Cross section ratios between different beam energies, such as 8 TeV/7 TeV, are highlighted as powerful precision tests that can discriminate between PDFs and probe BSM physics.
NNPDF3.0: Next generation parton distributions for the LHC Run IIjuanrojochacon
The document provides an overview of the forthcoming NNPDF3.0 PDF release from the NNPDF Collaboration. Key points include:
1) NNPDF3.0 includes over 1000 new data points from HERA and LHC experiments like ATLAS and CMS, improving constraints on PDFs.
2) Improved theory calculations are used, including approximate NNLO corrections for jet data and full NLO electroweak corrections.
3) The NNPDF methodology has been upgraded with a C++ code rewrite, validation on closure tests, and improvements to the fitting strategy and basis choices.
Parton Distributions at a 100 TeV Hadron Colliderjuanrojochacon
This document discusses parton distributions for a potential future 100 TeV hadron collider. It begins with an outline of topics to be covered, including the increased kinematic coverage from 14 TeV to 100 TeV, PDF luminosities over this energy range, and tools needed for PDF studies at 100 TeV. The document then examines the kinematic coverage at 100 TeV in detail, showing how it probes PDFs at smaller x values and allows access to higher mass scales. Plots demonstrate that PDF luminosities increase much more rapidly from 14 to 100 TeV for higher mass states. The discussion covers tools needed for FCC PDF studies, including behavior of PDFs at large-x, inclusion of a top quark PDF,
News from NNPDF: QED, small-x, and alphas(MZ) fitsjuanrojochacon
Juan Rojo presented recent work from the NNPDF collaboration on three spin-off fits from their NNPDF3.1 global analysis: NNPDF3.1QED, fits including small-x resummation, and a determination of the strong coupling constant αS(mZ). For NNPDF3.1QED, they are imposing the LUXqed formalism to constrain the photon PDF rather than extracting it from data. For small-x resummation fits, they find that including NNLO+NLLx theory stabilizes the small-x gluon and improves description of HERA data. Their preliminary αS(mZ) value is consistent with other determinations.
Parton Distributions at a 100 TeV Hadron Colliderjuanrojochacon
Usage of modern PDF sets with LHAPDF6 v6.1.5 is suitable for FCC studies and simulations. At a 100 TeV hadron collider, PDFs would need to be evaluated in more extreme regions of small-x, large-x, and large invariant masses than at the LHC. Photon-initiated processes could contribute significantly at the FCC due to large uncertainties in the photon PDF. Heavy quark PDFs, including for the top quark, should be included in matched calculations for FCC simulations rather than using a purely massless scheme.
aMCfast: Automation of Fast NLO Computations for PDF fitsjuanrojochacon
MadGraph5_aMCatNLO provides NLO calculations for arbitrary processes and their matching to parton showers, but existing fast interfaces are limited. A new tool called aMCfast provides a fast interface to MadGraph5_aMCatNLO, allowing its predictions to be used in global PDF fits. It precomputes matrix elements and interpolates them using grids, then reconstructs distributions for any PDFs or scales. This will increase the number and accuracy of processes in PDF fits, including electroweak corrections and photon-initiated effects, improving determination of PDFs from LHC data.
Parton Distributions and Standard Model Physics at the LHCjuanrojochacon
This document discusses parton distribution functions (PDFs) and recent developments. It notes that NNLO calculations are essential to reduce uncertainties in PDF analysis. Several key processes like inclusive jet production and top quark production are now available at NNLO. The document also discusses the inclusion of LHC data like W+charm, top quark, and jet data in global PDF fits. It highlights updates to various PDF fitting groups and the upcoming NNPDF3.0 release.
NNLO PDF fits with top-quark pair differential distributionsJuan Rojo
Juan Rojo presented a study on including top-quark pair differential distributions in NNLO global PDF fits. The distributions provide stringent constraints on the large-x gluon, comparable to inclusive jet data. Fitting normalized distributions and including one distribution from ATLAS and CMS improves the description of data and reduces PDF uncertainties, particularly at high masses important for BSM searches. Some tension is seen between ATLAS and CMS measurements that can be reduced by fitting the experiments separately. Differential top data will be essential for future global PDF fits.
Guide for visualizing JMA's GSM outputs using GrADSJMA_447
The document discusses visualizing JMA high-resolution GSM data with GrADS. It provides an overview of the JMA data service that provides GRIB2 forecast data. It then discusses preparing the data for visualization with GrADS, including using tools to create control and index files from GRIB2 data. Finally, it covers basic interactive operation and customization of images using GrADS.
Recent progress in proton and nuclear PDFs at small-xjuanrojochacon
1) The document discusses recent progress in proton and nuclear parton distribution functions (PDFs) at small values of x. PDFs describe the momentum distribution of quarks and gluons inside protons and nuclei.
2) Global analyses of experimental data from various processes are used to determine PDFs at hadronic scales, which are then evolved perturbatively to higher scales relevant for LHC predictions. Recent analyses include data from the LHC.
3) Probing PDFs at small x requires processes dominated by gluons at leading order, produced in the forward region with low invariant masses. Examples discussed are direct photon and charm production. LHCb and future forward calorimeter data provide constraints on the small-
PDFs at the LHC: Lessons from Run I and preparation for Run IIjuanrojochacon
This document summarizes parton distribution functions (PDFs) at the start of LHC Run II. It discusses the status of recent PDF sets from NNPDF, MMHT, CT, ABM, and HERAPDF. It notes some differences between these sets and the importance of PDF uncertainties for LHC measurements. The document also discusses benchmarks between PDF sets, comparisons using the APFEL online tool, and the prospects for including more ATLAS data in global PDF fits to further constrain PDFs.
Real-Time Pedestrian Detection Using Apache Storm in a Distributed Environment csandit
This document discusses real-time pedestrian detection using Apache Storm in a distributed environment. It proposes a methodology that distributes video frames across multiple nodes ("bolts") for parallel processing. Each bolt detects pedestrians in a different region of the frame. Only detection results, not full frames, are transmitted to reduce overhead. The methodology is implemented using Apache Storm and evaluated on a test system with improved processing speed. Pedestrian detection has applications in safety and analytics.
New dynamics in parton distributions at a 100 TeV hadron colliderjuanrojochacon
This document discusses parton distribution functions (PDFs) relevant for a future 100 TeV hadron collider. It summarizes that such a collider would probe PDFs at smaller x values than currently possible, down to x=10-9. It would also probe higher mass scales, up to masses of 10 TeV. Current PDF determinations have little constraint for x<10-4 or masses above 1 TeV. The increased energy would require considering effects like top quark PDFs, electroweak corrections, and high-energy resummation not important at lower energies. Polarized collisions could also provide insights into PDFs.
This document outlines José Cupertino Ruiz Vargas's PhD thesis on searching for diboson resonances in CMS data. It begins with an introduction to the standard model of particle physics and motivations for physics beyond the standard model, including the Randall-Sundrum model with extra dimensions. It then describes the CMS detector and object identification techniques. The analysis strategy is to select events with two opposite-sign leptons and two jets, and estimate backgrounds using Monte Carlo simulations and data-driven techniques. Unblinded results show agreement between data and background predictions in control regions.
This document discusses heaps and their use in implementing priority queues. It describes how a max-heap or min-heap is a complete binary tree that satisfies the heap property, where each internal node is greater than or equal to its children. It explains how a heap can be represented using a simple array and how to build a heap from an unsorted array in O(n) time by sifting nodes down. Deleting the root element and maintaining the heap property takes O(log n) time. Heap sort uses a heap to sort an array in O(n log n) time. Priority queues can be efficiently implemented using max-heaps.
Parton Distributions: future needs, and the role of the High-Luminosity LHCjuanrojochacon
1) Improved PDFs are needed to match the accuracy of higher-order calculations of cross sections and characterize properties of the Higgs boson and search for new physics.
2) The HL-LHC could significantly reduce PDF uncertainties through high-statistics measurements, especially in processes sensitive to large-x gluons and quarks like top quark pair production and Drell-Yan.
3) Preliminary studies generating HL-LHC pseudo-data show PDF uncertainties on the gluon-gluon and quark-antiquark luminosities could be reduced by 10-30% from top pair and Drell-Yan measurements respectively.
This document summarizes an internship project using the WRF-ARW model to simulate a tropical cyclone. The internship involved learning UNIX, WRF installation, configuration and running a simulation of Tropical Cyclone HudHud without data assimilation. The results showed the model predicted the cyclone track closely compared to observations. Future work proposed using more cyclones and assimilating Doppler radar data to evaluate impact on track and intensity forecasts. The internship provided valuable experience in operational forecasting and research using numerical weather prediction models.
NNPDF3.0: parton distributions for the LHC Run IIjuanrojochacon
NNPDF3.0 is a new PDF determination that includes updated data and theory improvements compared to NNPDF2.3. It includes all HERA-II data and new LHC measurements. The fitting code was rewritten in C++ and validated using closure tests. NNPDF3.0 shows reasonable agreement with NNPDF2.3 while improving descriptions of data and reducing uncertainties in some regions. It provides PDFs for use at the LHC Run II.
Constraints on the gluon PDF from top quark differential distributions at NNLOjuanrojochacon
- The document discusses constraints on the gluon PDF from top quark production at hadron colliders.
- It describes using the inclusive top quark pair production cross section to reduce uncertainties in the gluon PDF, especially in the large-x region between 0.1 and 0.5.
- Cross section ratios between different beam energies, such as 8 TeV/7 TeV, are highlighted as powerful precision tests that can discriminate between PDFs and probe BSM physics.
NNPDF3.0: Next generation parton distributions for the LHC Run IIjuanrojochacon
The document provides an overview of the forthcoming NNPDF3.0 PDF release from the NNPDF Collaboration. Key points include:
1) NNPDF3.0 includes over 1000 new data points from HERA and LHC experiments like ATLAS and CMS, improving constraints on PDFs.
2) Improved theory calculations are used, including approximate NNLO corrections for jet data and full NLO electroweak corrections.
3) The NNPDF methodology has been upgraded with a C++ code rewrite, validation on closure tests, and improvements to the fitting strategy and basis choices.
Parton Distributions at a 100 TeV Hadron Colliderjuanrojochacon
This document discusses parton distributions for a potential future 100 TeV hadron collider. It begins with an outline of topics to be covered, including the increased kinematic coverage from 14 TeV to 100 TeV, PDF luminosities over this energy range, and tools needed for PDF studies at 100 TeV. The document then examines the kinematic coverage at 100 TeV in detail, showing how it probes PDFs at smaller x values and allows access to higher mass scales. Plots demonstrate that PDF luminosities increase much more rapidly from 14 to 100 TeV for higher mass states. The discussion covers tools needed for FCC PDF studies, including behavior of PDFs at large-x, inclusion of a top quark PDF,
News from NNPDF: QED, small-x, and alphas(MZ) fitsjuanrojochacon
Juan Rojo presented recent work from the NNPDF collaboration on three spin-off fits from their NNPDF3.1 global analysis: NNPDF3.1QED, fits including small-x resummation, and a determination of the strong coupling constant αS(mZ). For NNPDF3.1QED, they are imposing the LUXqed formalism to constrain the photon PDF rather than extracting it from data. For small-x resummation fits, they find that including NNLO+NLLx theory stabilizes the small-x gluon and improves description of HERA data. Their preliminary αS(mZ) value is consistent with other determinations.
Parton Distributions at a 100 TeV Hadron Colliderjuanrojochacon
Usage of modern PDF sets with LHAPDF6 v6.1.5 is suitable for FCC studies and simulations. At a 100 TeV hadron collider, PDFs would need to be evaluated in more extreme regions of small-x, large-x, and large invariant masses than at the LHC. Photon-initiated processes could contribute significantly at the FCC due to large uncertainties in the photon PDF. Heavy quark PDFs, including for the top quark, should be included in matched calculations for FCC simulations rather than using a purely massless scheme.
aMCfast: Automation of Fast NLO Computations for PDF fitsjuanrojochacon
MadGraph5_aMCatNLO provides NLO calculations for arbitrary processes and their matching to parton showers, but existing fast interfaces are limited. A new tool called aMCfast provides a fast interface to MadGraph5_aMCatNLO, allowing its predictions to be used in global PDF fits. It precomputes matrix elements and interpolates them using grids, then reconstructs distributions for any PDFs or scales. This will increase the number and accuracy of processes in PDF fits, including electroweak corrections and photon-initiated effects, improving determination of PDFs from LHC data.
This document discusses parton distribution functions (PDFs) with intrinsic charm. It presents the motivation for fitting a charm PDF in global analyses, including stabilizing charm mass dependence, quantifying the non-perturbative charm component, and exploring implications for LHC phenomenology. The document summarizes previous fits allowing for intrinsic charm and issues they faced. It then presents new NNPDF fits that allow the charm PDF to be fitted, finding these fits describe EMC charm data and have stable gluon and charm PDFs under charm mass variations, with implications for precision LHC calculations.
PDF uncertainties the LHC made easy: a compression algorithm for the combinat...juanrojochacon
This document summarizes Juan Rojo's presentation on a new method for combining PDF sets called compressed Monte Carlo PDFs (CMC-PDFs). The method involves combining Monte Carlo replicas from different PDF sets, then compressing the large combined set into a smaller set that still accurately reproduces properties like uncertainties. Validation shows CMC-PDFs with only 25 replicas can reproduce uncertainties for a variety of LHC processes, providing a computationally efficient implementation of the PDF4LHC recommendation.
The document summarizes progress in the NNPDF global analysis of parton distribution functions. It discusses past NNPDF analyses from 2012-2015 and plans for future analyses, including NNPDF3.1 which will include new LHC data and improve the determination of intrinsic charm. It also presents results from fits allowing the charm content of the proton to be determined from data rather than assumed from perturbation theory, finding the data support a small intrinsic charm component within uncertainties.
Statistical issues in global fits: Lessons from PDF determinationsJuan Rojo
The document discusses statistical issues that arise in global fits to determine parton distribution functions (PDFs) from experimental data. It notes that PDF fits must combine data from different collision types and experiments, which can have inconsistent measurements. Traditional PDF fitting methods make restrictive assumptions that introduce bias, while the NNPDF approach uses neural networks and Monte Carlo replicas to avoid biases and faithfully represent uncertainties, including in regions with limited data. Inconsistent data poses challenges and requires delicate handling in global fits to obtain statistically sound PDF results.
This document discusses potential areas where lattice QCD calculations could provide input to help constrain parton distribution functions (PDFs) which are currently not well known. It identifies "benchmarks" where PDFs are already well determined, as well as "opportunities" where lattice calculations could have more impact. These include PDFs at large values of Bjorken x, the strange quark content of the proton, and charm content. The document also discusses how lattice data could be included in PDF global fits to help reduce PDF uncertainties.
News from NNPDF: new data and fits with intrinsic charmjuanrojochacon
Juan Rojo presented recent work by the NNPDF collaboration including: 1) inclusion of the final HERA legacy dataset which provides a moderate reduction in PDF uncertainties, 2) inclusion of new LHC data which constrains the large-x gluon PDF, and 3) ongoing work to perform fits with intrinsic charm and investigate implications for LHC phenomenology.
The document discusses the Monash 2013 tune of Pythia 8, which uses the NNPDF2.3LO parton distribution functions (PDFs). It notes that LO PDFs are important for describing non-perturbative physics in event generators. NNPDF2.3LO has a steeper gluon distribution at small values of x compared to the CTEQ6L PDF used in previous tunes. This allows the Monash 2013 tune to better describe precise forward data from experiments like TOTEM and CMS, which probe the gluon PDF in the low-x region.
The structure of the proton in the Higgs Boson Erajuanrojochacon
This document summarizes Juan Rojo's presentation on the structure of the proton in the Higgs boson era. The key points are:
1) The discovery of the Higgs boson marks a new era for particle physics and new discoveries may be found at the LHC in the next years.
2) While the Standard Model is successful, it is incomplete and new physics is needed to explain phenomena like dark matter. The LHC aims to further study the Higgs and search for new physics.
3) Determining the parton distribution functions that describe the proton's constituents is crucial for LHC analyses and requires a global analysis of experimental data using advanced theoretical techniques like neural networks.
This document summarizes the measurement of W boson production in association with a charm quark using 4.6 pb-1 of proton-proton collision data at √s = 7 TeV from the ATLAS detector at the LHC. Two analyses are performed to tag charm quarks: one identifies charm jets through semileptonic decays to muons, and one reconstructs charmed mesons. Cross sections are reported and compared to theoretical predictions from different parton distribution functions. The results support PDF sets with an enhanced strange quark contribution and SU(3) symmetric light quark seas, and disfavor those with suppressed strange quarks. The measured cross sections have total uncertainties of 5-7% and indicate symmetric strange and anti-
Precision determination of the small-x gluon from charm production at LHCbjuanrojochacon
This document discusses using LHCb data on charm production to constrain the small-x gluon and improve predictions for neutrino fluxes. LHCb data at 7 TeV, 5 TeV and 13 TeV provides stringent constraints on the small-x gluon beyond HERA. This improved gluon allows more accurate predictions for signals and backgrounds at neutrino telescopes. At a 100 TeV collider, inclusive cross sections depend directly on small-x PDFs, but using LHCb data leads to stabilized predictions with reduced uncertainties.
Improved Timing Estimation Using Iterative Normalization Technique for OFDM S...IJECEIAES
Conventional timing estimation schemes based on autocorrelation experience perfor- mance degradation in the multipath channel environment with high delay spread. To overcome this problem, we proposed an improvement of the timing estimation for the OFDM system based on statistical change of symmetrical correlator. The new method uses iterative normalization technique to the correlator output before the detection based on statistical change of symmetric correlator is applied. Thus, it increases the detection probability and achieves better performance than previously published methods in the multipath environment. Computer simulation shows that our method is very robust in the fading multipath channel.
Higgs Pair Production at the LHC and future collidersjuanrojochacon
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Parton distributions from high-precision collider datajuanrojochacon
Juan Rojo gave a seminar at the Technical University of Munich on July 13, 2017 about parton distributions from high-precision collider data. He discussed how parton distribution functions are essential for calculating cross sections at hadron colliders like the LHC, since they describe the probability of finding quarks and gluons within protons. Rojo explained that global analyses fit PDFs to diverse experimental data using statistical techniques like neural networks, and the PDFs can then provide predictions for new processes. He highlighted recent updates from the NNPDF collaboration in version 3.1 to include more precise LHC data and the option to fit the charm quark distribution.
Higgs pair production in vector-boson fusion at the LHC and beyondjuanrojochacon
The document discusses Higgs pair production, which can help uncover the mechanism of electroweak symmetry breaking. Double Higgs production allows reconstructing the full Higgs potential and probing the Higgs self-interaction. While production rates are small in the Standard Model, deviations from SM couplings could significantly increase rates. The document focuses on vector boson fusion channel, where requiring two forward jets and vetoing central jets can reduce backgrounds, and sensitivity to non-SM couplings improves at high di-Higgs invariant masses. Precision studies of Higgs pair production may reveal insights into electroweak symmetry breaking and new physics.
Discovery through precision: perturbative QCD at the dawn of the LHC Run IIjuanrojochacon
This document summarizes a seminar given by Juan Rojo on perturbative QCD at the dawn of LHC Run II. In the seminar, Rojo discussed how recent advances in perturbative QCD, such as higher precision parton distribution functions and higher-order calculations, have improved the prospects for new physics searches at the LHC. Rojo also presented recent work on topics like PDFs with threshold resummation, Higgs pair production, and charm production that further push the boundaries of perturbative QCD and its applications at the LHC.
CERN, Particle Physics and the Large Hadron Colliderjuanrojochacon
The document discusses particle physics research done at CERN using the Large Hadron Collider (LHC). It describes the LHC as the most powerful particle accelerator ever built, with a 27km long tunnel housing four detectors. The LHC collides protons together at high energies to study their constituent particles like quarks and search for new particles like the Higgs boson. It also allows researchers to recreate conditions shortly after the Big Bang and potentially observe mini black holes or extra dimensions at very small scales. The future includes planning for an even larger successor to the LHC to continue advancing understanding of fundamental physics.
The structure of the proton in the Higgs boson erajuanrojochacon
Juan Rojo gave a seminar at SLAC on July 4th, 2015 about the structure of the proton in the Higgs boson era and the role of the Large Hadron Collider. He discussed how the discovery of the Higgs boson completed the Standard Model but also opened new questions. Determining the parton distribution functions of protons with precision is important for phenomenology at the LHC, such as characterizing Higgs couplings and searching for new physics. Over the next 20 years, the LHC will play a key role in exploring these open questions.
Particle Physics, CERN and the Large Hadron Colliderjuanrojochacon
The document discusses particle physics research done at CERN's Large Hadron Collider (LHC). It describes the LHC as the most powerful particle accelerator ever built, with a 27 km long tunnel housing detectors that observe proton collisions at very high energies. One of the LHC's major discoveries was the Higgs boson particle in 2012. The document outlines how the LHC allows scientists to study the fundamental building blocks of matter at the smallest observable scales.
PDF uncertainties and the W mass: Report from the Workshop “Parton Distributi...juanrojochacon
The document summarizes discussions from a workshop about reducing uncertainties in parton distribution functions (PDFs) that affect measurements of the W boson mass. Key topics discussed included issues modeling the Z boson's transverse momentum, inconsistencies between PDF sets, and the need for additional LHC measurements like of W/Z production to reduce PDF uncertainties in future W mass measurements to below 10 MeV. Participants agreed more work is needed to understand differences between PDF sets and include relevant LHC data in global fits.
Characterizing New Physics with Polarized Beams in Hadron Collisionsjuanrojochacon
This document discusses how polarized proton beams could help characterize new physics discovered at the LHC or FCC. Polarized and unpolarized parton distribution functions have different behaviors, so cross sections with polarized beams would provide insights into couplings to different quark flavors. Single and double spin asymmetries could distinguish between new physics models that predict similar unpolarized signatures. While more study is needed, polarized beams could significantly aid understanding of the structure and couplings of any discovered heavy new particles.
The Standard Model and the LHC in the Higgs Boson Erajuanrojochacon
The document discusses the Standard Model of particle physics and the role of the Large Hadron Collider (LHC) following the discovery of the Higgs boson. It provides background on the development of the Standard Model and discovery of its key particles like quarks, gluons, and weak bosons. It describes the LHC as the most powerful particle collider built to explore physics at the highest energies and probe unanswered questions left by the Standard Model. Four main detectors at the LHC, including ATLAS and CMS, precisely measure collision products to explore fundamental particles and forces.
The Structure of the Proton in the Higgs Boson Erajuanrojochacon
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Boosting Strong Higgs Pair Production at the LHCjuanrojochacon
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1) Higgs pair production allows for stringent tests of the understanding of electroweak symmetry breaking, but has low rates in the Standard Model.
2) Higgs pair production in vector boson fusion is small in the Standard Model but provides unique information on the hhVV coupling. It can be substantially enhanced in composite Higgs models.
3) Preliminary results show the hhVV coupling can be measured with 25-30% precision at the 14 TeV LHC with 300 fb-1, and 10-15% precision with 3000 fb-1, while the FCC could achieve
Pinning down the hhVV coupling from Higgs boson pair production in vector-b...juanrojochacon
The document discusses using Higgs boson pair production in vector-boson fusion (VBF) to probe the hhVV coupling. VBF Higgs pair production provides unique sensitivity to this coupling. While the standard model rate for VBF Higgs pair production is small, it can be substantially enhanced in composite Higgs models with new strong dynamics. Preliminary results indicate the hhVV coupling can be measured with 25-30% precision at the LHC with 300 fb-1, improving to 10-15% precision with 3000 fb-1. The FCC could determine the coupling with few-percent accuracy. Analyzing the boosted 4b and 2b2l final states allows probing deviations in the hhVV coupling growing with di-Higgs mass.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
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This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
1. Juan Rojo!
VU Amsterdam & Theory group, Nikhef!
!
on behalf of the NNPDF Collaboration!
!
!
PDF4LHC Working Group meeting!
07/03/2017
NNPDF3.1
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
1
2. 2
Why NNPDF3.1?
An update of the NNPDF global analysis was motivated by:!
The availability of a wealth of high-precision PDF-sensitive measurements from the
Tevatron, ATLAS, CMS and LHCb, including processes such as the Z pT and differential
distributions in top-quark production that have never been used before in a PDF fit!
The striking recent progress in NNLO QCD calculations, which allows to include the
majority of PDF-sensitive collider measurements into a fully consistent NNLO global
analysis!
The recent realisation that fitting the charm PDF has several advantages in the global QCD
fit (beyond comparison with non-perturbative models), in particular stabilise the dependence
with mcharm and improve the data/theory agreement for some of the most precise collider
observables.
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
3. 3
NNPDF3.1: fit settings
!
PDF evolution and DIS structure functions up to
NNLO are computed with APFEL in the FONLL GM-
VFN scheme!
Hadronic data included using APPLgrid/FastNLO
interfaced to MCFM/aMC@NLO/NLOjet++,
supplemented by bin-by-bin NNLO/NLO K-factors
obtained separately for each specific process!
The APFELgrid tool is used to combine a priori
PDF evolution with applgrid interpolated coefficient
functions, achieving an speed-up by up to three
orders of magnitude for the evaluation of hadronic
cross-sections during the PDF fit
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Bertone, Carrazza, Hartland CPC 16
4. 4
Fitted vs Perturbative charm!
The change of scheme between a theory with 3 active quarks and another with 4 active quarks is
determined by the matching conditions:
!
Most global fits (including NNPDF3.0) assume that c(3)(x)=0, in other words, the scale-independent
(intrinsic) charm content of the proton vanishes!
!
Releasing this assumption leads to the modified matching conditions
Scale-independent !
(intrinsic) charm
Scale-dependent!
charm PDF: to be
determined from
data at Q0>mc
Perturbative contribution
from charm-anticharm
radiation off gluons
!
Whether or not c(3)(x)=0 is a good assumption can only be determined from data
NNPDF3.1 fits obtained both for a fitted
and for a perturbative charm PDF
Ball, Bonvini, Rottoli, JHEP 17!
Ball et al, PLB 17
5. 5
Fitted charm recap!
Based on the NNPDF3.0 settings, we produced NLO PDF sets with fitted charm!
Small differences on light quarks and gluons!
For the charm PDF at high scales, differences only for large-x, x < 0.08
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
NNPDF, EPJC 2016
!
Fitting the charm PDF leads to an improved
data/theory agreement, a reduced dependence on
mcharm and allows to compare with non-
perturbative models of the proton structure!
In NNPDF3.1, the new collider data allow a
precise determination of the charm PDF, avoiding
the need to rely on the EMC charm data
NNPDF, EPJC 2016
6. 6
Outline
!
NNPDF3.1: !
Fit quality!
Fitted charm vs perturbative charm!
Comparison with NNPDF3.0 and other recent PDF sets!
A bit of phenomenology!
!
Impact of individual datasets:!
Jets at NNLO!
The Z pT!
top quark distributions!
Gauge boson production!
The strange and charm content of the proton!
!
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Disclaimer: I will certainly not have enough time for all these results, please see backup for more. !
All these results will be discussing in great detail in the upcoming paper!
8. 8
New datasets in NNPDF3.1
Combined HERA inclusive data Run I+II quark singlet and gluon
D0 legacy W asymmetries Run II quark flavor separation
ATLAS inclusive W, Z rap 7 TeV 2011 strangeness
ATLAS inclusive jets 7 TeV 2011 large-x gluon
ATLAS low-mass Drell-Yan 7 TeV 2010+2011 small-x quarks
ATLAS Z pT 7,8 TeV 2011+2012 medium-x gluon and quarks
ATLAS and CMS tt differential 8 TeV 2012 large-x gluon
CMS Z (pT,y) 2D xsecs 8 TeV 2012 medium-x gluon and quarks
CMS Drell-Yan low+high mass 8 TeV 2012 small-x and large-x quarks
CMS W asymmetry 8 TeV 2012 quark flavor separation
CMS 2.76 TeV jets 2012 medium and large-x gluon
LHCb W,Z rapidity dists 7 TeV 2011 large-x quarks
LHCb W,Z rapidity dists 8 TeV 2012 large-x quarks
Measurement Data taking Motivation
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
9. 9
Fit quality: 𝛘2
NNLO FittedCharm NNLO PertCharm NLO FittedCharm NLO PertCharm
HERA 1.16 1.20 1.16 1.16
ATLAS 1.13 1.19 1.45 1.50
CMS 1.04 1.06 1.20 1.20
LHCb 1.46 1.46 1.94 1.93
!
For collider data, NNLO theory leads to a markedly better fit quality that than NLO (since the new
data included has small experimental uncertainties, and NNLO corrections mandatory)!
The global PDF analysis where the charm PDF is fitted leads to a slightly superior fit quality than
assuming a perturbatively generated charm PDF!
In general good description of all the new collider measurements included in NNPDF3.1
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
12. 12
Impact of new data
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/d(x,Q
2
d(x,Q
0
0.02
0.04
0.06
0.08
0.1
0.12
3.0 dataset
global dataset
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
(x,Q
+
)/s
2
(x,Q+
s
0
0.02
0.04
0.06
0.08
0.1
0.12
3.0 dataset
global dataset
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
)/d(x,Q2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
3.0 dataset
global dataset
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
(x,Q
+
)/s
2
(x,Q+
s
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2 3.0 dataset
global dataset
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
Significant reduction of PDF uncertainties due to the new data, in particular for the
gluon and the down quark (and the antiquarks as well)!
Shifts induced by the new data typically consistent at the one-sigma level with the 3.0
datasets results, though in some cases bigger effects are seen (i.e. the large-x down quark) !
The new data has decisive impact on PDFs!
PRELIMINARY
PRELIMINARY
14. 14
Comparison with NNPDF3.0
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.0
NNPDF3.1
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
)/u(x,Q2
u(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.0
NNPDF3.1
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
)/d(x,Q2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.0
NNPDF3.1
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
(x,Q
+
)/s2
(x,Q+
s
0.8
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2 NNPDF3.0
NNPDF3.1
2
GeV4
=102
NNLO, Q
Agreement between 3.1 and 3.0 at the one-sigma level, with 3.1 exhibiting in most cases
reduced PDF uncertainties!
In general the quark PDFs tend to be harder, specially in the case of strangeness due to
the impact of the ATLAS W,Z 2011 data!
Increase in the gluon for x=0.01 by 0.5-sigma, suppression at large-x from top pair data
PRELIMINARY
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
15. 15
new data vs new methodology
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.0
NNPDF3.1 (NNPDF3.0 dataset)
NNPDF3.1 global
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10)[ref]2
)/d(x,Q2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.0
NNPDF3.1 (NNPDF3.0 dataset)
NNPDF3.1 global
2
GeV4
=102
NNLO, Q
Impact of new data
new methodology (mostly fitting charm)
PRELIMINARY
PRELIMINARY
17. 17
Higgs production cross-sections
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
For gluon-initiated processes, good agreement between 3.1 and 3.0 with reduced PDF
uncertainties in the latter case!
For quark-initiated processes, the new collider data pulls towards higher cross-sections!
The new ABMP16 set is in reasonable agreement with the other sets provided the PDG
value of the strong coupling is used
PRELIMINARY
PRELIMINARY
18. 18
Large-x PDF positivity
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Ideally, allow PDFs to become negative but ensure that a large number of ``mock’’ observables are positive-
definite (i.e. W’ cross-section at 5 TeV)!
In NNPDF3.0 we already include DIS SFs and DY u*ubar, d*dbar, s*sbar xsecs, and we will include more in
our next release (non-trivial improvement of neural network training algorithm required)!
Adding the many new LHC observables already improves a lot the large-x positivity issues in NNPDF3.1!
See Michelangelo’s talk!
PRELIMINARY
19. 19 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
Jet production !
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
)/g(x,Q2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
Global
No jet data
2
GeV4
=102
NNLO, Q
PRELIMINARY
20. 20
Jets at NNLO
J. Currie, Krakow 01/17
!
If the jet pT is used as
central scale, NNLO/NLO
K-factors only a few
percent!
NNLO/NLO shift
within NLO scale
uncertainties!
This trend holds for all
rapidity regions
!
NNLO results available only for then ATLAS 7 TeV 2011 measurement!
In NNPDF3.1, use NLO matrix elements for jets, computed with pT as central scale, and add the
NLO scale uncertainties as additional theory uncertainty
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
21. 21
Inclusive jets in NNPDF3.1!
In NNPDF3.1, we include the central rapidity bin of the ATLAS 7 TeV 2011 inclusive jets, finding
good fit quality: 𝛘2 (NNLO)=1.06 and 𝛘2 (NLO)=1.12!
For CMS we include the inclusive jets at 2.76 TeV, also good data/theory agreement!
Good description of all other jet datasets, already included in NNPDF3.0!
Jet data still quite constraining for the large-x gluon, though impact less dramatic as in previous
NNPDF releases due to the presence of other gluon-sensitive measurements in the fit (more later)
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
Global
No jet data
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
)/d(x,Q2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
Global
No jet data
2
GeV4
=102
NNLO, Q
PRELIMINARY
PRELIMINARY
Impact of jet data in NNPDF3.1
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
22. 22 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
The Z transverse momentum
23. 23
Impact of Z pt data
!
For the first time in a global fit, the transverse momentum of the Z boson has been included!
NNLO calculations for K-factors from Boughezal and Petriello, very CPU time intensive!!
All the Z pT measurements from ATLAS and CMS at 8 TeV included
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Dedicated study: Boughezal, Guffanti, Petriello, Ubiali, in preparation
24. 24
Impact of Z pt data
Juan Rojo ATLAS PDF Fit Forum, 10/02/2017
ATLAS 8 TeV (M,pT) CMS 8 TeV (y,pT)
!
Good fit quality to 8 TeV ATLAS and CMS, though very sensitive to stat fluctuations!
Included 1% of residual stat uncertainty from K-factor calculation, else 𝛘2 (NNLO) worse by factor 4.
Tiny changes in shape of TH prediction worsen significantly fit quality since exp uncorr errors v small !
Despite fitting 8 TeV data, worse description of 7 TeV data (tension between 7 and 8 TeV?)
ATLAS 8 TeV (y,pT) ATLAS 8 TeV (M,pT) CMS 8 TeV (y,pT)
𝛘 0.9 0.9 1.3
𝛘 2.4 1.2 3.6
PRELIMINARY
NNPDF3.1
NNPDF3.1
25. 25
Impact of Z pT data
!
Impact on many PDFs: harder gluon at medium-x (relevant for ggF Higgs) and softer quarks in
the same region.!
The region of intermediate-x is the region where Z pT data is expected to have most sensitivity!
New important addition to the toolbox of global PDF fits!
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.1 no Z pT
NNPDF3.1
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/d(x,Q
2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.1 no Z pT
NNPDF3.1
2
GeV4
=102
NNLO, Q
PRELIMINARY
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
NB the ATLAS Z pt 7 TeV data not included in these fits
26. 26 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
The strange and charm!
content of the proton !
27. 27
The strangeness content of the proton
!
xFitter analysis of the ATLAS W,Z 2011 inclusive data prefers a symmetric strange sea with small
uncertainty, at odds with all other PDF fits!
Actually the ATLAS data suggest that there are more strange than up and down sea quarks in the
proton, which is very difficult to understand from non-perturbative QCD arguments !
Can one accommodate the ATLAS W,Z 2011 data in the global fit? What happens to strangeness?
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
28. 28
The strangeness content of the proton
!
Confirmed the strange symmetric fit preferred by the ATLAS W,Z 2011 measurements, though we
find PDF uncertainties larger by a factor 2!
The global fit accommodates both the neutrino data and the ATLAS W,Z 2011 ( 𝛘2
nutev=1.1,
𝛘2
AWZ11=1.8 ) finding a compromise value for RS=0.61+-0.14!
Mild tension in the global fit (1.5-sigma level at most) when simultaneously included neutrino data,
CMS W+charm and ATLAS W,Z 2010+2011
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
29. 29
Charm content of proton revisited!
The new LHC experiments provide additional constraints on non-perturbative charm !
Including the EMC charm data, we find evidence for non-perturbative charm at the 1.5 sigma level.
Even without EMC data, non-perturbative charm bounded < 0.5% at the 68% CL
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
Non-perturbative charm is certainly small, but
data exhibit preference for non-zero value
NNPDF3.0 dataset (no EMC): 1.6 +- 1.2%!
NNPDF3.1 dataset (no EMC): 0.3 +- 0.4%
30. 30 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
Top-quark pair!
differential distributions!
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
)/g(x,Q2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
Global
no Z pt data
No top data
No jet data
2
GeV4
=102
NNLO, Q
31. 31
!
Top-quark pair production driven by the gluon-
gluon luminosity!
NNLO calculations for stable top quarks
available (with decays in the pipeline)!
Recent precision data from ATLAS and CMS at 8
TeV with full breakdown of statistical and systematic
uncertainties!
For the first time, included ATLAS+CMS 8 TeV
differential top measurements into the global PDF fit
The large-x gluon from top-quark production
Czakon, Hartland, Mitov, Nocera, Rojo 16
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
32. 32
The large-x gluon from top-quark production
!
From CMS we include the
normalised top-quark pair
rapidity at 8 TeV!
In addition we include total
cross-section data at 7,8 and 13 TeV!
Good agreement between NNLO
theory and the LHC data
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
From CMS we include the normalised
top-quark pair rapidity at 8 TeV!
From ATLAS we include the
normalised top pair rapidity at 8 TeV
PRELIMINARY
33. 33
!
PDF uncertainties reduced by more than a
factor two for mtt ≳ 500 GeV!
Our choice of fitted distributions, yt and ytt,
reduces the risk of BSM contamination
(kinematical suppression of resonances), which
might show up instead in mtt and pt
T, where PDF
uncertainties are now much smaller!
Self-consistent program to use top data to
provide better theory predictions
Improved sensitivity to BSM dynamics!
with top-quark final states!
The large-x gluon from top-quark production
mtt data not used in fit
Czakon, Hartland, Mitov, Nocera, Rojo 16
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
34. 34
Impact on the gluon!
In NNPDF3.1 we have three groups of processes that provide direct information on the gluon:
inclusive jets, top pair differential, and the Z transverse momentum!
Are the constraints from each of these groups consistent among them? Yes!
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
Global
no Z pt data
No top data
No jet data
2
GeV4
=102
NNLO, Q
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
35. 35 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
Inclusive weak boson production!
36. 36
CMS Drell-Yan 8 TeV
!
Drell-Yan production at 8 TeV updates a previous 7 TeV measurement (already in NNPDF3.0) and is
expected to provide useful information on quark flavour separation!
Intensive NNLO calculation to achieve good enough statistical accuracy. !
Kinematical cuts exclude the first rapidity bin, which vanishes at LO due to lepton acceptance cuts
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
37. 37
CMS Drell-Yan 8 TeV
!
Improved description as compared to NNPDF3.0!
Despite good visual data/theory agreement, the fit description is poor: 𝛘2/Ndat = 3.3!
Difficult to trace the origin of the problem since only full covariance matrix (no breakdown
of systematics) is provided
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
38. 38
CMS Drell-Yan 8 TeV
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/d(x,Q
2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
Global
no CMSDY2D12
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
(x,Qd)/2
(x,Qd
0.9
0.95
1
1.05
1.1
1.15
Global
no CMSDY2D12
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
!
This measurement indeed affects large-x quarks and antiquarks …!
… but only shift in central values, with PDF errors stable or even increasing in some cases!
Tension with other experiments in global fit? Internal tensions?
PRELIMINARY
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
39. 39
Forward W,Z production at LHCb
!
NNPDF3.1 includes the complete 7 TeV and 8 TeV W,Z measurements in the muon channel, as
well as most of the electron channel measurements!
Crucial to account for the cross-correlations between the W and Z data!
Expect improved quark-flavor separation for large-x quarks, thanks to LHCb forward kinematics!
Complementary information to that from W, Z production from ATLAS and CMS
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
40. 40
Forward W,Z production at LHCb
NNPDF3.1
!
Improved agreement as compared to NNPDF3.0, specially in the forward region!
Significant reduction of PDF uncertainties wrt to NNPDF3.0, by almost factor 2!
NNLO QCD does not describe the most central bin of the 8 TeV W data: excluded from fit
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
41. 41
Forward W,Z production at LHCb
!
The reduction of PDF uncertainties from the LHCb
data is more marked for the large-x quarks!
Note shift on central values, in addition to
reducing PDF errors!
For the down quark, PDF errors decrease by almost
a factor 2 for x=0.2
Juan Rojo LHCb EW meeting, 23/02/2017
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/u(x,Q
2
u(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.1, no LHCb data
NNPDF3.1, with LHCb data
2
GeV4
=102
NNLO, Q
x
2−
10 1−
10
)[ref]2
)/d(x,Q2
d(x,Q
0
0.02
0.04
0.06
0.08
0.1
0.12
NNPDF3.1, no LHCb data
NNPDF3.1, with LHCb data
NNLO, Q = 100 GeV
PRELIMINARY
PRELIMINARY
PRELIMINARY
42. 42
NNPDF3.1: summary and outlook
!
Several new datasets included, from the HERA and Tevatron legacy data to precision
LHC electroweak production measurements, the 8 TeV Z pT data, and top quark
production differential distributions!
Good stability with respect to NNPDF3.0, with main differences being a reduction of
the large-x PDF uncertainties and an improved quark flavour separation!
Improved stability of the gluon from the combination of top, Z pT, and jet data!
Increase in strangeness from inclusion of the ATLAS W,Z 2011 data!
Improved fit quality once the charm PDF is fitted, rather than perturbatively generated.
Non-negligible differences at the PDF level. NNPDF3.1 fits for the two options will be
released.!
NNPDF3.1 will be available in LHAPDF very soon!
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
43. 43
NNPDF3.1: summary and outlook
!
Several new datasets included, from the HERA and Tevatron legacy data to precision
LHC electroweak production measurements, the 8 TeV Z pT data, and top quark
production differential distributions!
Good stability with respect to NNPDF3.0, with main differences being a reduction of
the large-x PDF uncertainties and an improved quark flavour separation!
Improved stability of the gluon from the combination of top, Z pT, and jet data!
Increase in strangeness from inclusion of the ATLAS W,Z 2011 data!
Improved fit quality once the charm PDF is fitted, rather than perturbatively generated.
Non-negligible differences at the PDF level. NNPDF3.1 fits for the two options will be
released.!
NNPDF3.1 will be available in LHAPDF very soon!
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Thanks for your attention!
44. 44 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
!
!
Extra Material !
!
45. 45
Fitting data with sub-percent errors!
In several of the new experiments in NNPDF3.1, uncorrelated uncertainties are very small, at the few
permille level. This implies that is required to get the shape of the theory prediction correct to the same
accuracy, which can be very challenging for CPU-intensive NNLO calculations!
We tackle this by including the MC stat integration error from the theory prediction as an additional
uncorrelated systematic error in the 𝛘2!
This also implies that even very small variations of the correlation model (which ultimately determines
what is correlated and what uncorrelated) can lead to very large variations of the 𝛘2 for same input theory!
To avoid this, measurements should provide an estimate of the uncertainty associated with correlations
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
49. 49
Comparison with ABMP16
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
NNPDF3.0 global
ABMP16 as=0.118
ABMP16 as default
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/d(x,Q
2
d(x,Q
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
NNPDF3.0 global
ABMP16 as=0.118
ABMP16 as default
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/u(x,Q
2
u(x,Q
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
NNPDF3.0 global
ABMP16 as=0.118
ABMP16 as default
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]2
(x,Q
+
)/s2
(x,Q+
s
0.85
0.9
0.95
1
1.05
1.1
1.15
1.2
NNPDF3.0 global
ABMP16 as=0.118
ABMP16 as default
2
GeV4
=102
NNLO, Q
50. 50 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Impact of ATLAS 7 TeV Z pT data
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.1 no Z pT
NNPDF3.1
2
GeV4
=102
NNLO, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/d(x,Q
2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
NNPDF3.1 no Z pT
NNPDF3.1
2
GeV4
=102
NNLO, Q
with 8 TeV Z pt data with 8 TeV Z pt data
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/g(x,Q
2
g(x,Q
0.9
0.95
1
1.05
1.1
1.15
no 7 TeV Z pT data
with 7 TeV Z pT data
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
x
4−
10
3−
10 2−
10 1−
10
)[ref]
2
)/d(x,Q
2
d(x,Q
0.9
0.95
1
1.05
1.1
1.15
no 7 TeV Z pT data
with 7 TeV Z pT data
2
GeV4
=102
NNPDF3.1 NNLO FC, Q
(only 8 TeV Z pt data) (only 8 TeV Z pt data)
51. 51
Forward W,Z production at LHCb
NNPDF3.1
!
For Z production, also improved shape agreement in NNPDF3.1!
Overall fit quality for LHCb experiments: 𝛘2/N = 1.4 (1.9) at NNLO (NLO). Note NNLO crucial!
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
52. 52
Charm content of proton revisited
x
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
)
2
(x,Q+
xc
0.01−
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
NNPDF3.1, no LHCb data
NNPDF3.1, with LHCb data
NNLO, Q = 2 GeV
!
The new collider measurements provide important constraints on the large-x charm PDF, for
instance, the 7 and 8 TeV W,Z measurements from LHCb !
Models where non-perturbative charm can carry much more than 1% of the total proton’s
momentum are strongly disfavoured by the LHCb data
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
53. 53
Impact on the gluon!
The best precision in the large-x gluon is achieved by combining jets with top-pair and Z pt data!
In terms of constraining power at large-x, we find the hierarchy: jets > ttbar differential > Z pt
x
0.1 0.2 0.3 0.4 0.5
)[ref]
2
)/g(x,Q
2
g(x,Q
0
0.05
0.1
0.15
0.2
0.25
Global
no Z pt data
No top data
No jet data
2
GeV4
=102
NNLO, Q
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
RelativePDFerror
54. 54
The strangeness content of the proton
x
4−
10 3−
10 2−
10 1−
10
)2
(x,QSR
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6 NNPDF3.0
NNPDF3.1 global
NNPDF3.1 collider
NNLO, Q=1.65 GeV
!
Collider-only and global fits in agreement within PDF uncertainties!
In NNPDF3.1 strangeness is less suppressed than in NNPDF3.0 (mostly due to the new data) but still
in agreement within PDF uncertainties!
The collider-only fit is becoming competitive with the global fit!
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
55. 55
CMS 8 TeV W rapidity
!
Useful for quark flavour separation !
xFitter analysis has demonstrated usefulness for PDF constraints !
This measurement was already in good agreement with NNPDF3.0
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
56. 56
CMS 8 TeV W rapidity
!
Good agreement data / theory, similar to that in NNPDF3.0, with 𝛘2/Ndat = 1.0 at NNLO!
Note reduction of PDF uncertainties in the cross-section predictions from all the new electroweak
production data included
PRELIMINARY
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
57. 57 Juan Rojo PDF4LHC WG Meeting, 07/03/2017
Good agreement with
experimental data, as was
the case in NNPDF3.0
Looking forward to the 13 TeV data!
Inclusive jets in NNPDF3.1
PRELIMINARY
PRELIMINARY
58. 58
Jets at NNLO
J. Currie, Krakow 01/17
!
If the jet pT is used as
central scale, NNLO/NLO
K-factors only a few
percent!
NNLO/NLO shift
within NLO scale
uncertainties!
This trend holds for all
rapidity regions
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
59. 59
Higgs production !
in gluon fusion
Gluinos, KK gravitons,!
boosted top-quarks….
charm,bottom!
soft QCD, MC tuning,!
High-energy astroparticles
One glue to bind them all
Exploit PDF-sensitive LHC measurements to constrain the gluon at small-x!
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
60. 60
The prompt flux at neutrino telescopes
Observation of Ultra-High Energy (UHE) neutrino events heralds start of Neutrino Astronomy!
New window to the Universe, but interpretation of UHE data requires control over backgrounds
How well do we understand !
this prompt flux?!
Do we really control charm production
in such extreme kinematics?
IceCube/KM3NET/…
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
61. 61
The low-x gluon from charm production
c
c
D+
ν+X
Lab frame Elab = (2mpECR)1/2
ECR = 100 PeV Elab ≈ 14 TeV
Overlap kinematics between charm production
in UHE cosmic rays and at the LHC
Sensitivity to!
small-x gluon
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
62. 62
Strategy: use LHC data to provide state-of-the-art predictions for backgrounds at neutrino telescopes
x
6−
10 5−
10 4−
10 3−
10 2−
10 1−
10
)
2
=4GeV
2
g(x,Q
0
2
4
6
8
10
12
14
16
=0.118sαNNPDF3.0 NLO
data
+-
,D
0
no LHCb D
data (wgt)
+-
,D
0
with LHCb D
data (unw)
+-
,D
0
with LHCb D
=0.118sαNNPDF3.0 NLO
x
6−
10 5−
10 4−
10 3−
10 2−
10 1−
10
PercentagePDFuncertainty
0
20
40
60
80
100
120
140
160
180
200
=0.118sα), NNPDF3.0 NLO,2
g(x,Q
data
+-
,D
0
no LHCb D
data
+-
,D
0
with LHCb D
=0.118sα), NNPDF3.0 NLO,2
g(x,Q
Figure 11: Left plot: The NNPDF3.0 small-x gluon, evaluated at Q = 2 GeV, comparing the baseline
global fit result with with the new gluon obtained after the inclusion in the fit of the LHCb charm
production data. In the latter case, we show both the reweighted results (rwg) and those after the
unweighting procedure. Right plot: comparison of the percentage PDF uncertainties for the NNPDF3.0
We predict that detection of the prompt neutrino flux should be within reach
Include 7 TeV LHCb forward charm production data in the global fit!
Validate perturbative QCD calculations on collider data, and constrain the small-x gluon!
Compute optimised predictions for prompt neutrino fluxes at high energies!
!
The low-x gluon from charm production
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
63. 63
LHCb charm production from 5 to 13 TeV!
Updated analysis based on normalized cross-sections at 5,
7 and 13 TeV and cross-section CoM energy ratios (avoiding
double counting)!
Good description of all datasets, compatible pull on the
small-x gluon except the R13/7 ratio!
The N5+N7+N13 combination leads to a reduction of the
small-x gluon PDF errors by an order of magnitude!!
The most precise D0 data at 5 and 13 TeV cannot be
described by NLO QCD and are excluded from the fit:
NNLO calculation needed?
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
64. 64
UHE neutrino-nucleus cross-sections
Precision studies of extreme QCD with IceCube/KM3NET: the ultimate DIS experiments!
!
High-precision QCD predictions of neutrino-nucleus cross-section up to 106 PeV (low-x sea
quarks driven by gluon through DGLAP evolution)!
Few-percent QCD uncertainties in the UHE cross-sections up to the highest energies: unique
opportunity for BSM searches and precision astrophysical studies
ν
W/Z
q(x ⋍10-7,Q⋍MW)
Juan Rojo PDF4LHC WG Meeting, 07/03/2017
65. 65
The strangeness content of the proton
!
Significant improvement in description of the experimental data in NNPDF3.1 as compared to 3.0
PRELIMINARY
NNPDF3.1
Juan Rojo PDF4LHC WG Meeting, 07/03/2017