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Status	  of	  the	  CMS	  	  SM	  Higgs	  Search	                            Joe	  Incandela	                             ...
Status	  of	  the	  CMS	  	                 SM	  Higgs	  Search	  Raw ΣET~2 TeV14 jets with ET>40                         ...
July 4th 2012 The Status of the Higgs Search   J. Incandela for the CMS COLLABORATION                                     ...
The	  Standard	  Model	                            4
The	  Standard	  Model	                                                       meas   fit       meas                    Mea...
The	  Standard	  Model	  J. Incandela for the CMS COLLABORATION                                                           ...
The	  Standard	  Model	                                                               	  	  1	  Missing	  piece:	  Higgs	 ...
The	  Standard	  Model	                                                               	  	  1	  Missing	  piece:	  Higgs	 ...
Where	  we	  stood	  last	  week	                                                 1.  Mtopvs.	  MW	  J. Incandela for the ...
Higgs	  boson	  production	  J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search           ...
Higgs	  boson	  production	  J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search           ...
Higgs	  boson	  decays	  J. Incandela for the CMS COLLABORATION                                               5	  decay	  ...
CMS	  Exclusion	  Potential	  J. Incandela for the CMS COLLABORATION                                               §  Not...
CMS	  Discovery	  potential	  J. Incandela for the CMS COLLABORATION                                               p-­‐val...
How	  is	  it	  possible	  to	  go	  so	  far	  so	  fast?	                                                               ...
Total	  weight	  	  	  	  	  	  	  	  	  14000	  t	  Overall	  diameter	  	  	  15	  m	                            ECAL   ...
Current	  Operational	  Status*	                                                                    Pixels	  J. Incandela ...
ECAL	  calibration,	  2012	  data	                                                                             Single	  el...
‣CMS	  assume a 50% keep for	  8	  TeV	  and	  high	  PU	  in	  2012	                                                     ...
GEN-SIM/AODSIM Produc                                                                                             MC	  Pro...
Reconstruction                 21
Global	  Event	  Description	  (Pflow)	  	                                                          Made possible by CMS gr...
Electron/Photon	  reconstruction	  J. Incandela for the CMS COLLABORATION                                                 ...
Electron	  identification	                                                 §  Multivariate	  e	  identification	  in	  2012...
Muon	  reconstruction	  and	  identification	  J. Incandela for the CMS COLLABORATION                                      ...
Particle-­‐based	  isolation	                                                 Sum	  energy	  of	  particles	  in	  ΔR	  J....
Tau	  Identification	                                                 §  Tau	  identification:	                            ...
Jet	  Identification	                                                    •         Jet	  reconstruction	  J. Incandela for ...
Standard	  Model:	  	  Precision	  Jets,	  W,	  and	  γ*/Z	  	  J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The St...
Standard	  Model	  at	  7	  TeV	  2010-­‐2011	                                                 8.8                        ...
H	  èγγ	               31
July 4th 2012 The Status of the Higgs Search   J. Incandela for the CMS COLLABORATION                                     ...
H	  →	  γγ Overview	                                                 §  Main	  analysis	  is	  a	  Multi-­‐Variate-­‐Anal...
Search	  for	  a	  narrow	  mass	  peak	  with	  two	                                                                     ...
Photon	  Energy	  Scale	  and	  Resolution	  J. Incandela for the CMS COLLABORATION                                       ...
§  Photon	  pre-­‐selection:	                                                   Photon	  ID	                             ...
The γγ Vertex Choice                                               §  Mass reconstructionJ. Incandela for the CMS COLLABO...
Diphoton	  MVA	                                                   §  Diphoton	  MVA	  trained	  on	  signal	  and	  backg...
Di-­‐jet	  Tagging	  J. Incandela for the CMS COLLABORATION                                               §  Exclusive	  ...
Di-­‐jet	  Tagging:	  Selection	                                                 Analysis	  improvements	  in	  2012:	  	 ...
7	  TeV	  Mass	  Distribution	  in	  Categories	  J. Incandela for the CMS COLLABORATION                                  ...
8	  TeV	  Mass	  Distribution	  in	  Categories	  J. Incandela for the CMS COLLABORATION                                  ...
S/B	  Weighted	  Mass	  Distribution	                                                 §  Sum	  of	  mass	  distributions	...
95%	  CL	  Exclusion	  for	  SM	  Higgs	  	  J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs S...
P-ValuesJ. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search                                ...
Fitted Signal StrengthJ. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search                  ...
H	  èZZ*	                47
H	  →ZZ(*)	  →4l	  	  (l	  =	  e,μ):	  the	  golden	  channel	                                                            ...
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
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CMS - Bosone di Higgs
CMS - Bosone di Higgs
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CMS - Bosone di Higgs
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CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
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CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
CMS - Bosone di Higgs
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Transcript of "CMS - Bosone di Higgs"

  1. 1. Status  of  the  CMS    SM  Higgs  Search   Joe  Incandela   UCSB/CERN   July  4,  2012   1
  2. 2. Status  of  the  CMS     SM  Higgs  Search  Raw ΣET~2 TeV14 jets with ET>40 Joe  Incandela  Estimated PU~50 UCSB/CERN   July  4,  2012   2
  3. 3. July 4th 2012 The Status of the Higgs Search J. Incandela for the CMS COLLABORATION On  behalf  of  the  CMS  Collaboration  3
  4. 4. The  Standard  Model   4
  5. 5. The  Standard  Model   meas fit meas Measurement Fit |O −O |/σ 0 1 2 3 (5) Δαhad(mZ) 0.02758 ± 0.00035 0.02768 mZ [GeV] 91.1875 ± 0.0021 91.1874 ΓZ [GeV] 2.4952 ± 0.0023 2.4959 0 σhad [nb] 41.540 ± 0.037 41.479 Rl 20.767 ± 0.025 20.742 0,l Afb 0.01714 ± 0.00095 0.01645 Al(Pτ) 0.1465 ± 0.0032 0.1481 Rb 0.21629 ± 0.00066 0.21579 Rc 0.1721 ± 0.0030 0.1723 0,b Afb 0.0992 ± 0.0016 0.1038 0,c Afb 0.0707 ± 0.0035 0.0742 Ab 0.923 ± 0.020 0.935 Ac 0.670 ± 0.027 0.668 Al(SLD) 0.1513 ± 0.0021 0.1481 2 lept sin θeff (Qfb) 0.2324 ± 0.0012 0.2314 mW [GeV] 80.399 ± 0.023 80.379 ΓW [GeV] 2.085 ± 0.042 2.092 mt [GeV] 173.3 ± 1.1 173.4 July 2010 0 1 2 3 5
  6. 6. The  Standard  Model  J. Incandela for the CMS COLLABORATION meas fit meas Measurement Fit |O −O |/σ 0 1 2 3 (5) Δαhad(mZ) 0.02758 ± 0.00035 0.02768 mZ [GeV] 91.1875 ± 0.0021 91.1874 ΓZ [GeV] 2.4952 ± 0.0023 2.4959 0 σhad [nb] 41.540 ± 0.037 41.479 Rl 20.767 ± 0.025 20.742 0,l Afb 0.01714 ± 0.00095 0.01645 Al(Pτ) 0.1465 ± 0.0032 0.1481 R Confirmed  to  better  than  1  %   Rb 0.21629 ± 0.00066 0.21579 0.1721 ± 0.0030 0.1723 uncertainty  by  100’s  of   c 0,b A fb 0.0992 ± 0.0016 0.1038July 4th 2012 The Status of the Higgs Search 0,c precision  m± 0.020 0.935 easurements   A fb 0.0707 ± 0.0035 0.0742 A b 0.923 Ac 0.670 ± 0.027 0.668 Al(SLD) 0.1513 ± 0.0021 0.1481 2 lept sin θeff (Qfb) 0.2324 ± 0.0012 0.2314 mW [GeV] 80.399 ± 0.023 80.379 ΓW [GeV] 2.085 ± 0.042 2.092 mt [GeV] 173.3 ± 1.1 173.4 July 2010 0 1 2 3 6
  7. 7. The  Standard  Model      1  Missing  piece:  Higgs  J. Incandela for the CMS COLLABORATION meas fit meas Measurement Fit |O −O |/σ 0 1 2 3 (5) Δαhad(mZ) 0.02758 ± 0.00035 0.02768 mZ [GeV] 91.1875 ± 0.0021 91.1874 ΓZ [GeV] 2.4952 ± 0.0023 2.4959 0 σhad [nb] 41.540 ± 0.037 41.479 Rl 20.767 ± 0.025 20.742 0,l Afb 0.01714 ± 0.00095 0.01645 Al(Pτ) 0.1465 ± 0.0032 0.1481 R Confirmed  to  better  than  1  %   Rb 0.21629 ± 0.00066 0.21579 0.1721 ± 0.0030 0.1723 uncertainty  by  100’s  of   c 0,b A fb 0.0992 ± 0.0016 0.1038July 4th 2012 The Status of the Higgs Search 0,c precision  m± 0.020 0.935 easurements   A fb 0.0707 ± 0.0035 0.0742 A b 0.923 Ac 0.670 ± 0.027 0.668 Al(SLD) 0.1513 ± 0.0021 0.1481 2 lept sin θeff (Qfb) 0.2324 ± 0.0012 0.2314 mW [GeV] 80.399 ± 0.023 80.379 ΓW [GeV] 2.085 ± 0.042 2.092 mt [GeV] 173.3 ± 1.1 173.4 July 2010 0 1 2 3 7
  8. 8. The  Standard  Model      1  Missing  piece:  Higgs  J. Incandela for the CMS COLLABORATION meas fit meas Measurement Fit |O −O |/σ 0 1 2 3 (5) Δαhad(mZ) 0.02758 ± 0.00035 0.02768 mZ [GeV] 91.1875 ± 0.0021 91.1874 ΓZ [GeV] 2.4952 ± 0.0023 2.4959 0 σhad [nb] 41.540 ± 0.037 41.479 Rl 20.767 ± 0.025 20.742 0,l Afb 0.01714 ± 0.00095 0.01645 Al(Pτ) 0.1465 ± 0.0032 0.1481 R Confirmed  to  better  than  1  %   Rb 0.21629 ± 0.00066 0.21579 0.1721 ± 0.0030 0.1723 uncertainty  by  100’s  of   c 0,b A fb 0.0992 ± 0.0016 0.1038July 4th 2012 The Status of the Higgs Search 0,c precision  m± 0.020 0.935 easurements   A fb 0.0707 ± 0.0035 0.0742 A b 0.923 Ac 0.670 ± 0.027 0.668 Al(SLD) 0.1513 ± 0.0021 0.1481 2 lept sin θeff (Qfb) 0.2324 ± 0.0012 0.2314 mW [GeV] 80.399 ± 0.023 80.379 ΓW [GeV] 2.085 ± 0.042 2.092 mt [GeV] 173.3 ± 1.1 173.4 July 2010 0 1 2 3 8
  9. 9. Where  we  stood  last  week   1.  Mtopvs.  MW  J. Incandela for the CMS COLLABORATION §  Tevatron  MW  Tour  de  Force!!      mW  =  80385  ±  15  MeV  (  World  Ave  –   Mar  2012)   §  Shifts  for  SM  Higgs  expectation   2.  Colliders  leave  little  space    July 4th 2012 The Status of the Higgs Search ~Mt2 This  is  the  main  story  of   the  past  year   ~ln(mH) Eliminated    ~475  GeV  of  the   mass  range.     9 9
  10. 10. Higgs  boson  production  J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search §  √s=8  TeV:  25-­‐30%  higher  σ  than  √s=7  TeV  at  low  mH   §  All  production  modes  to  be  exploited   §  gg  VBF    VH  ttH   §  Latter  3  have  smaller  cross  sections  but  better  S/B  in  many  cases     10
  11. 11. Higgs  boson  production  J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search §  √s=8  TeV:  25-­‐30%  higher  σ  than  √s=7  TeV  at  low  mH   §  All  production  modes  to  be  exploited   §  gg  VBF    VH  ttH   §  Latter  3  have  smaller  cross  sections  but  better  S/B  in  many  cases     11
  12. 12. Higgs  boson  decays  J. Incandela for the CMS COLLABORATION 5  decay  modes  exploited   §  High  mass:      WW,  ZZ     §  Low  mass:    bb,  ττ,  WW,  ZZ,  γγ   §  Low  mass  region  is  very  rich  but   also  very  challenging:  July 4th 2012 The Status of the Higgs Search main  decay  modes  (bb,  ττ)  are  hard       to  identify  in  the  huge  background     §  Very  good  mass  resolution   (1%):      Hàγγ    and    HàZZà4l   12
  13. 13. CMS  Exclusion  Potential  J. Incandela for the CMS COLLABORATION §  Not-­‐yet-­‐excluded  region:     ~[115-­‐130]  GeV   §  The  five  decay  modes   discussed  today  have   comparable  sensitivities  for   exclusion.   §  Most  analyses  used  in  this   combination  have  been  re-­‐ optimized.  In  order  to  avoid  July 4th 2012 The Status of the Higgs Search the  possibility  of  an   unintended  bias,  all  selection   criteria  in  the  analyses  of  the   2011  and  2012  data  were   fixed  before  looking  at  the     result  in  the  signal  region.   13
  14. 14. CMS  Discovery  potential  J. Incandela for the CMS COLLABORATION p-­‐values     §  Probability  that  background   fluctuates  to  give  an  excess   as  large  as  the  (average)   signal  size  expected  for  a   SM  Higgs.      Takes  into  account  all  analysis  July 4th 2012 The Status of the Higgs Search steps,  estimated  backgrounds,   etc.  for  the  5  search  channels   indicated.   §  Excellent  prospects    for   exploring  properties   14
  15. 15. How  is  it  possible  to  go  so  far  so  fast?   LHC  performance:  2010-­‐2011-­‐2012  J. Incandela for the CMS COLLABORATION CMS Total Integrated Luminosity, p-p 7 7 Stellar  performance   Total Integrated Luminosity (fb-1) 2012  certified   of  the  LHC  enables   6 ‘Golden’:  5.19  m-­‐1  (85%)   6 2010, s = 7 TeV 2011, s = 7 TeV Muon:        5.62  m-­‐1  (92%)   all  experiments  to   5 2012, s = 8 TeV 5 produce  significant   physics  results   4 4July 4th 2012 The Status of the Higgs Search 3 3 2 2 Many  thanks  to  the   LHC  teams  and  the   1 1 many  others  who   0 0 made  this  possible!   02/05 02/07 01/09 Time in year 15
  16. 16. Total  weight                  14000  t  Overall  diameter      15  m   ECAL 76k scintillating PbWO4 crystals CMS  Overall  length              28.7  m   MUON  ENDCAPS HCAL Scintillator/brass Interleaved ~7k ch 473 Cathode Strip Chambers (CSC) 432 Resistive Plate Chambers (RPC) 3.8T Solenoid IRON  YOKE   Preshower Si Strips ~16 m2 ~137k ch YBO Foward Cal YB1- Steel + quartz 2 Fibers 2~k ch Pixels  &  Tracker •  Pixels (100x150 µm2) " ~1m 2 ~66M ch" • Si Strips (80-180 µm)" ~200 m2 ~9.6M ch MUON  BARREL 250 Drift Tubes (DT) and 480 Resistive Plate Chambers (RPC) 16
  17. 17. Current  Operational  Status*   Pixels  J. Incandela for the CMS COLLABORATION Strips   Preshower   ECAL  Endcap   ECAL  Barrel   HCAL  Outer   HCAL  Forward   HCAL  Endcap   HCAL  Barrel   muon  RPC  July 4th 2012 The Status of the Higgs Search muon  DT   muon  CSC   0   10   20   30   40   50   60   70   80   90   100   Pixel     Strip     Preshower ECAL     ECAL     HCAL     HCAL     HCAL     HCAL     Muon     Muon     Muon     Tracker Tracker Barrel Endcaps Barrel Endcaps Forward Outer DT CSC RPC 97.1% 97.75% 97.1% 99.16% 98.54% 99.92% 99.96% 99.88% 96.88% 99.1% 97.67% 98.2% *As of June 15 2012 17
  18. 18. ECAL  calibration,  2012  data   Single  electron  energy  scale  (E/p)  stability   Zàee  invariant  mass  distribution  for  J. Incandela for the CMS COLLABORATION in  barrel  measured  with  W  àeν  events   electrons  measured  in  the  barrel   1.03 Relative E/p scale CMS 2012 Preliminary with LM correction Mean 1 1.02 s = 8 TeV L = 3.95 fb-1 without LM correction RMS 0.0019 1 / LM correction Mean 0.97 1.01 RMS 0.0063 1 Electrons  with   0.99 low  or  no   0.98 Bremsstrahlung   0.97 0.96 0.95 0.94 EB: Prompt Reconstruction!! ECAL Barrel: Prompt Reco 0.93July 4th 2012 The Status of the Higgs Search 12/04 19/04 26/04 03/05 10/05 17/05 24/05 31/05 07/06 0 50 100 date (day/month) §  Wàeν  E/p:  Stable  E  scale  during  2012  run  after  light  monitoring   (LM)  corrections:   §  ECAL  Barrel  (EB):        RMS  stability  after  corrections  0.19%   §  Zàee:  Good  resolution  with  preliminary  energy  calibration  for  2012:      Instrumental  resolution:  1.0  GeV  in  ECAL  Barrel     18
  19. 19. ‣CMS  assume a 50% keep for  8  TeV  and  high  PU  in  2012   If we Preparations   processing efficiency up factor in the Tier-0 and 90% §  ‣ Reasonably optimistic and leaves little room for catching up Last  Autumn    J. Incandela for the CMS COLLABORATION §  cpu  time  for  high  PU  >40  sec/event   §  Memory  usage  well  above  2  GB.   600 ‣    Means  we  With 40%all  the  cores!   cannot  use   machine 2GB/core 3GB/core Prompt Reco (Hz) 450 §  Even  200  Hz  looked  this leaves live time hard!   §  Task  force  20% contingency started  December   300 §  Major  success!   §  Improvements   150 ‣2.5  in  skeep most ofhave §  A  factor   This assumes we peed  July 4th 2012 The Status of the Higgs Search and    Under  ~15”  per  event  on  average     0 20 30 40 50 60 70 lxbatch §  Much  reduced  memory  use   Time Per Event (s)    Well  under  2  GB     Jan 12 Prompt  Reconstruction  at  Tier-­‐0:     3 §  Physics  performance  unchanged     Limit  on  our  data-­‐taking  rate  versus  event   §  Kept  our  AAA  rating:   processing  time  for  low  and  high  memory      E.g.  no  explicit  pT  threshold  on  tracks   use  cases   19
  20. 20. GEN-SIM/AODSIM Produc MC  Production  Capabilities     §  GEN-­‐SIM  @  Tier-­‐2’s  J. Incandela for the CMS COLLABORATION §  Sustain  400M/Month   GEN-­‐SIM      900M,  600M  past  2   months  but  had  help   from  Tier-­‐1’s   §  Redigi-­‐Rereco@   Tier-­‐1’s  July 4th 2012 The Status of the Higgs Search §  Sustain  1B/month   Redigi-­‐Rereco      Peaks  high  as  2.3B   20  
  21. 21. Reconstruction 21
  22. 22. Global  Event  Description  (Pflow)     Made possible by CMS granularity and high magnetic fieldJ. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search §  Optimal  combination  of  information  from  all  subdetectors   §  Returns  a  list  of  reconstructed  particles   §  e,μ,γ,  charged  and  neutral  hadrons      Used  in  the  analysis  as  if  it  came  from  a  list  of  generated  particles      Used  as  building  blocks  for  jets,  taus  ,  missing  transverse  energy  ,   isolation  and  PU  particle  identification   22
  23. 23. Electron/Photon  reconstruction  J. Incandela for the CMS COLLABORATION Electrons     ECAL  Barrel  (EB)  July 4th 2012 The Status of the Higgs Search §  Cluster  reconstruction  in  ECAL     §  Common  for  both  electrons  and  photons  (Electrons  also  reconstructed  as  photons)   §  Designed  to  collect  bremsstrahlung    and  conversions  in  extended  phi  region   §  Dedicated  track  reconstruction  for  electrons   §  Gaussian  Sum  Filter  allows  for  tracks  w/large  bremsstrahlung     §  Photon  identification  specific  to  Hèϒϒ   §  Energy  scale  and  resolution   §  Extensive  control  with  Z  and  J/ψèee  for  both  electrons  and  photons   23
  24. 24. Electron  identification   §  Multivariate  e  identification  in  2012  J. Incandela for the CMS COLLABORATION §  ECAL,  tracker,  ECAL-­‐tracker-­‐HCAL  matching,impact  parameter   §  30%  efficiency  improvement  in  H→ZZ→4e  wrt  cut  based  ID   §  Multivariate  training  against  background  in  data    July 4th 2012 The Status of the Higgs Search η  variance    ECAL  Barrel  (EB)     pT<20  GeV   Cut  Based  vs  MVA  ID   24
  25. 25. Muon  reconstruction  and  identification  J. Incandela for the CMS COLLABORATION §  Start  with  particle  flow  muons   Tighter  quality     §   Efficiency  above  96%  down  to  pT  =  5  GeV     criteria  applied     §  Above  99%  efficiency  for  pT  >  10  GeV   in  some  analyses   §  Efficiency  in  data  using  J/Ψ  and  Z  peak  July 4th 2012 The Status of the Higgs Search J/Ψ→µµ     Z→µµ     Tag&Probe     Efficiency  is  stable  in  high   Tag&Probe   PU  environment   25
  26. 26. Particle-­‐based  isolation   Sum  energy  of  particles  in  ΔR  J. Incandela for the CMS COLLABORATION Detector  vs  Particle  Flow   cone  around  the  lepton   • Global  event  description   Detector Isolation eliminates    double  counting   Particle Flow Isolation ELECTRONS  July 4th 2012 The Status of the Higgs Search Efficiency  is  stable  in  high  PU   environment   Endcaps   pT  <  10  GeV   MUONS   Pile-­‐up  contribution:   •  Negligible  for  charged  hadrons  (vertexing)   •  Neutrals  corrected  w/global  energy  density  (ρ)   26
  27. 27. Tau  Identification   §  Tau  identification:   τ-­‐>  πν   τ-­‐>  a1ν   τ-­‐>  ρν  J. Incandela for the CMS COLLABORATION §  Reconstruct  individual  decay  modes     §  Charged  hadrons  +  electromagnetic  obj   §  EM  strips  account  for  material  effects     1  Prong   3  Prong   1  Prong  +  Strip   §  Tau  isolation:   Tau ID + Isolation efficiency §  Multivariate  discriminator  using  sum  of   energy  deposits  in  dR  rings  around  the  tau    July 4th 2012 The Status of the Higgs Search Real  taus   Fake  taus   27
  28. 28. Jet  Identification   •  Jet  reconstruction  J. Incandela for the CMS COLLABORATION •  Reconstruction  with  particle  flow  objects    July 4th 2012 The Status of the Higgs Search Typical jet Pileup jet §  Pileup  jets  structure  differs  wrt  regular  jets:   §  Pileup  jets  originate  from  several  overlapping  jets  which  merge  together   §  Likelihood  grows  rapidly  with  high  pileup   §  Discriminant  exploits  shape  and  tracking  variables   §  discrimination  both  inside  and  outside  tracker  acceptance   28
  29. 29. Standard  Model:    Precision  Jets,  W,  and  γ*/Z    J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search Inclusive  jet  and  dijets.  2-­‐4%  JES.     Constrains  gluon  PDF  up  to  x=0.6   Differential  Drell-­‐Yan   cross  section:  2.5M  µµ   pairs  tests  NNLO  cross   sections  and  PDFs     CMS-PAS-QCD-11-004 CMS-PAS-EWK-11-007 29 29
  30. 30. Standard  Model  at  7  TeV  2010-­‐2011   8.8 CMS Preliminary, s=7 TeV CMSJ. Incandela for the CMS COLLABORATION [pb] W CMS e/ µ +jets+btag 164 ± 3 ± 12 ± 7 5 CMS 95%CL limit TOP-11-003 (L=0.8-1.09/pb) 12 (val ± stat. ± syst. ± lum) 10 Z Production Cross Section, σtot CMS measurement (stat ⊕syst) ≥1j theory prediction 16 CMS dilepton (ee,µ µ ,eµ ) 170 ± 4 ± 16 ± 8 104 ≥1j TOP-11-005 (L=1.14/fb) (val ± stat. ± syst. ± lum) ≥2j ≥2j Wγ CMS all-hadronic 136 ± 20 ± 40 ± 8 40 10 3 ≥3j Zγ TOP-11-007 (L=1.09/fb) (val ± stat. ± syst. ± lum) ≥3j ≥4j WW CMS dilepton (µ τ) 149 ± 24 ± 26 ± 9 26 102 ≥4j WZ TOP-11-006 (L=1.09/fb) (val ± stat. ± syst. ± lum) ZZ 17 10 H(127) CMS 2010 combination 154 ± ± 6 Approx. NNLO QCD 17 → ZZ arXiv:1108.3773 (L=36/pb) (val ± tot. ± lum.) jet ET > 30 GeV γ ET > 10 GeV jet |η | < 2.4 Δ R(γ ,l) > 0.7 CMS e/ µ +jets+btag 150 ± 9 ± 17 ± 6 1 17July 4th 2012 The Status of the Higgs Search arXiv:1108.3773 (L=36/pb) (val ± stat. ± syst. ± lum) NLO QCD 36 pb-1 36 pb-1 1.1 fb-1 4.7 fb-1 CMS dilepton (ee,µ µ ,eµ ) 168 ± 18 ± 14 ± 7 10-1 14 JHEP10(2011)132 arXiv:1105.5661 (L=36/pb) (val ± stat. ± syst. ± lum) PLB701(2011)535 CMS-PAS-EWK-11-010 CMS-PAS-HIG-11-025 CMS-PAS-EWK-10-012 CMS e/ µ +jets 173 ± 14 ± 36 ± 7 29 arXiv:1106.0902 (L=36/pb) (val ± stat. ± syst. ± lum) Theory: Langenfeld, Moch, Uwer, Phys. Rev. D80 (2009) 054009 -0.5 MSTW2008(N)NLO PDF, scale ⊗ PDF(90% C.L.) uncertainty §  Fabulous  agreement   0 50 100 150 200 250 300 §  Lots  of  data   σ(tt) (pb)  …  on  to  the  Higgs…     30 30
  31. 31. H  èγγ 31
  32. 32. July 4th 2012 The Status of the Higgs Search J. Incandela for the CMS COLLABORATION H èγγ candidate
  33. 33. H  →  γγ Overview   §  Main  analysis  is  a  Multi-­‐Variate-­‐Analysis  (MVA)  J. Incandela for the CMS COLLABORATION §  MVAs  for  photon  ID  and  event  classification      Fit  mass  distribution  in  4  event  classes  based  on  a  diphoton  MVA  output  +   2  di-­‐jet  categories   §  Improvement  in  expected  limit  ~15%  over  cut-­‐based  analysis   §  Cross-­‐checked  with  an  alternative  background  model  extraction:          Fit  output  of  a  2nd  MVA  combining  diphoton  MVA  and  mγγ    using  data  in   mass  sidebands  to  construct  the  background  model  July 4th 2012 The Status of the Higgs Search §  Also  cross-­‐checked  with  a  cut  based  analysis   §  Simple  and  robust      Cut  based  photon  ID  and  event  classification   ­  Fit  data  mass  distribution  in  2  rapidity  x  2  shower  shape  =4  categories  with   different  Signal  over  Background  (S/B)  +  2  di-­‐jet  categories   §  Published  for  2011  data        Phys.Lett.  B710  (2012)  403-­‐425  arXiv:1202.1487   33
  34. 34. Search  for  a  narrow  mass  peak  with  two   isolated  high  Et  photons    J. Incandela for the CMS COLLABORATION 2012 8 TeV §  Blind  analysis  in  2012   §  Re-­‐reco  2011  data  into   unchanged  2011   analysis   §  Background  MC  only   used  for  analysis   optimization,  Z-­‐>ee  July 4th 2012 The Status of the Higgs Search also  to  measure     photon  efficiencies  and   resolution  with  data   34
  35. 35. Photon  Energy  Scale  and  Resolution  J. Incandela for the CMS COLLABORATION §  ECAL  cluster  energies  corrected  using  a  MC  trained  multivariate  regression   §  Improves  resolution  and  restores  flat  response  of  energy  scale  versus  pileup   ­  Inputs:  Raw  cluster  energies  and  positions,  lateral  and  longitudinal  shower  shape  variables,  local  shower   positions  w.r.t.  crystal  geometry,  pileup  estimators   §  Regression  also  used  to  provide  a  per  photon  energy  resolution  estimate   §  To  measure  the  Energy  Scale  and  resolution:  use  Z→e+e-­‐   E5x5"July 4th 2012 The Status of the Higgs Search ESC" ESC corr" Both  EB  |η|<1   Effect  of  the   highR9   regression  on  the     Z-­‐>ee  peak   35
  36. 36. §  Photon  pre-­‐selection:   Photon  ID   §  ETγ1/mγγ>3,  ETγ2/mγγ>4   §  Photon  Id  a  bit  tighter  than  trigger  selection  and  MC  EM  enrichment  filters  J. Incandela for the CMS COLLABORATION    Efficiency  measured  using  tag  and  probe  with  Z→ee   §  Electron  veto:  Efficiency  measured  using  tag  and  probe  with  Z→µµγ   §  MVA  based  photon  ID  discriminates  photons  from  fakes:   §  Inputs:  isolation,  shower  shape,  per  event  energy  density,  pseudorapidity    July 4th 2012 The Status of the Higgs Search Validation   with  Z→ee   (inverted   electron  veto)   36
  37. 37. The γγ Vertex Choice §  Mass reconstructionJ. Incandela for the CMS COLLABORATION §  Depends on the correct position of the primary vertex §  Interaction vertex is identified using tracks from recoiling jets and underlying event plus conversions §  correct in ~83% of cases for pileup in 2011 sample. §  correct in ~80% of cases for pileup in 2012 sample. §  Vertex identification with a BDT §  Input variables: Σpt2, Σpt projected onto the γγ transverse direction, pt asymmetry and conversions §  Correct vertex finding probability also estimated using a BDTJuly 4th 2012 The Status of the Higgs Search Data-­‐MC   efficiency  for   Z-­‐>μμ   After   Efficiency  to   removing  the   identify   μ  tracks   correct   vertex  
  38. 38. Diphoton  MVA   §  Diphoton  MVA  trained  on  signal  and  background  MC  with  input  variables  largely   independent  of  mγγ J. Incandela for the CMS COLLABORATION §  Kinematics:  pT  and  η  of  each  photon,  and  cosΔφ  between  the  2  photons   §  Photon  ID  MVA  output  for  each  photon   §  per-­‐event  mass  resolution  and  vertex  probability   §  Encode  all  relevant  information  on  signal  vs  background  discrimination  (aside  from  mγγ   itself)  into  a  single  di-­‐photon  MVA  output    to  first  order  independent  of  mγγ Cat 1 " Cat 1 " Cat 3" Cat 2" Cat 0" Cat 3" Cat 2" Cat 0"July 4th 2012 The Status of the Higgs Search §  Residual  data-­‐MC  disagreement   §  For  BG  only  make  analysis  sub-­‐optimal   §  For  signal  would  cause  some  category  migration  included  in  the  systematic  errors   38
  39. 39. Di-­‐jet  Tagging  J. Incandela for the CMS COLLABORATION §  Exclusive  selection  of  di-­‐photon   events  with  VBF-­‐like  topology:   Di-­‐jet  event  with:     §  Two  high  pT  jets    with  large  pseudo-­‐ •   diphoton  mass  121.9  GeV   rapidity  difference  and  invariant  mass   •   dijet  mass  1460  GeV   §  High  S/B   •   jet  pT:  288.8  and  189.1  GeV     •   jet  η:  -­‐2.022  and  1.860   §  ~80%-­‐pure  VBF  events  for  large  di-­‐ jet  invariant  masses  July 4th 2012 The Status of the Higgs Search 39
  40. 40. Di-­‐jet  Tagging:  Selection   Analysis  improvements  in  2012:      J. Incandela for the CMS COLLABORATION §  Split  di-­‐jet  tagged  events  in  two  categories  based  on  Mjj  and  jet  pT   §  ~15%  improvement  in  sensitivity  for  dijet  category     §  better  sensitivity  to  separate  different  Higgs  production  modes     §  Removal  of  jets  from  pileup  events     §  Based  on  the  jet  shape  variables,  tracks  in  jet  and  vertexing   §  Cross-­‐checked  using  Z+jet  and  γ+jet  events   Dijet selection cutsJuly 4th 2012 The Status of the Higgs Search 40
  41. 41. 7  TeV  Mass  Distribution  in  Categories  J. Incandela for the CMS COLLABORATION Untagged 0 Untagged 1 Untagged 2 §  Background  model  is  July 4th 2012 The Status of the Higgs Search entirely  from  data.   §  Fit  to  mass  distribution  in   each  category  with   Untagged 3 Dijet tag polynomial  functions  (3rd   to  5th  degree)   §  keep  bias  below  20%  of  fit   error.   §  causes  some  loss  of   performance  due  to  number   of  parameters  in  fit  function.     41
  42. 42. 8  TeV  Mass  Distribution  in  Categories  J. Incandela for the CMS COLLABORATION Untagged 0 Untagged 1 Untagged 2July 4th 2012 The Status of the Higgs Search Untagged 3 Dijet tight Dijet loose 42
  43. 43. S/B  Weighted  Mass  Distribution   §  Sum  of  mass  distributions  for  each  event  class,  weighted  by  S/B  J. Incandela for the CMS COLLABORATION §  B  is  integral  of  background  model  over  a  constant  signal  fraction  interval  July 4th 2012 The Status of the Higgs Search 43
  44. 44. 95%  CL  Exclusion  for  SM  Higgs    J. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search §  Expected  95%  CL  exclusion  0.76  times  SM  at  125  GeV   §  Large  range  with  expected  excusion  below  σSM   §  Largest  excess  at  125  GeV   44
  45. 45. P-ValuesJ. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search §  Minimum local p-value at 125 GeV with a local significance of 4.1 σ §  Similar excess in 2011 and 2012 §  Independent cross check analyses give similar results §  Global significance in the full search range (110-150 GeV) 3.2 σ 45
  46. 46. Fitted Signal StrengthJ. Incandela for the CMS COLLABORATIONJuly 4th 2012 The Status of the Higgs Search Combined best fit signal Best fit signal strength strength consistent between σ/σSM = 1.56±0.43 x SM, different classes consistent with SM. 46
  47. 47. H  èZZ* 47
  48. 48. H  →ZZ(*)  →4l    (l  =  e,μ):  the  golden  channel   Clean  signature:  narrow  peak,  low  background  July 4th 2012 The Status of the Higgs Search J. Incandela for the CMS COLLABORATION Background:    irreducible  ZZ(*);    reducible  Z+jets,  ttbar,  WZ   One  of  the  best  performing  channels   in  the  whole  mass  range  …   …  but  extremely  demanding  channel  for   selection,  requiring  the  highest  possible   efficiencies  (lepton  Reco/ID/Isolation).     Production cross sections 8 σ (pp→H→ZZ(*)→4l) [fb] Small branching ratio 7 + - + - 6 H!l l l l (l = e,μ) 5 4 3 H!e+e- μ+μ- 2 1 + - H!e e e e + - 0 100 126 200 300 400 500 600 mH [GeV] . 48
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