Daniela KirilovaInstitute of Astronomy and NAOBulgarian Academy of Sciences, Sofia, BulgariaSEENET-MTP Workshop: Beyond the Standard Models - BW2013Vrnjacka Banja, Serbia, April 25 -29, 2013
Astrophysical and cosmological observations data – necessityof BSMs physicsThe contemporary LCDM contains already considerableDE+DM, unknown nature components constitute 95% of Universe matter!Inflation, Baryon Asymmetry, etc.to understand these puzzles physics BSM is requiredto propose the DM, DE, inflaton candidates , etcORchange the theoretical basis of SCM (alternative grav. theory, etc.)Neutrino : experimental data firmly established physics BSMsSMs assumptions: m=0, Neff=3, L=0, equilibrium FD distribution. Neutrino oscillations expt challenged all theseThis talk : some neutrino characteristics BSMtheir cosmological effects and constraints
Relic neutrino predicted by SCMNeutrino beyond SMsneutrino oscillations, non-zero massesinert neutrino, distortionsLeptogenesis by neutrino oscillationsBBN - the Early Universe Probe and SMP TestCosmological Effects and BBN Constraints on NeutrinoOscillationsCosmological Effects and BBN Constraints on LChange of constraints in case of L or/and inert neutrinoExcess radiation density in the Universe? eV neutrino sagaPossible explanations: extra particles, mixing, decays, L
Tν = Te = TγT1 MeV equilibrium neutrinos due to weak interactionsCNB Formation in SCMAt RD stage neutrinos are important component, influence considerably H,n-p kinetics, etc.2 2~ F EГ NG 2~ TGgH effNeutrinos from CNB are expected to be the most numerous particles after CMB photons.-αα-α-αβαβαβαβαeeeeννννννννννννTdec(νe) ~ 2 MeV Tdec(νμ,τ) ~ 3 MeVT~me, photons were heated T=(4/11)1/3 Tcmbγγ -een 339.3 cm-302 2393.14 eVmh 1e1T)(p,f p/T 2.984 0.008 (LEP)N T ~1 MeV As the Universe cools the rate of interaction decrease and could no longer keepneutrino in equilibrium.N = 3.046 not 3RELIC NEUTRINO BACKGROUNDSince decoupling neutrino were free streaming, i.e. cosmological neutrino background.Since Tdec(ν) is close to me, neutrinos shared a small part of the entropy releaseNeutrino oscillations account slightly change neutrino particle and energy densitiesDolgov, Hansen & Semikoz,1997,Mangano et al,02,0502 2394.12 eVcmh n 335.7 cm-3
Though numerous, CNB direct detection is very difficult because it is anextremely elusive particle due to its weak interactions and extremely lowenergy expected for neutrinos today.Figure from ASPERA roadmapIndirect CNB detection is possible due to its effect on BBN,CMB, LSS.CMB&LSS feel the total neutrino density. BBN is precise probe also of neutrinoenergy distribution, mass differences and mixing, chemical potential, etc.02393.14 eVmh -3339.3 cmn 0.001 0.02 T0~ 1.9 K.
Neutrino in Standard Cosmological Model• massles• Neutrino spectra have the equilibrium Fermi-Dirac distribution (an assumption).• The lepton asymmetry is zero (an assumption). Neutrino contribution to the energy density of the UniverseEffective number of relativisticneutrino speciesexp( / )/(1 exp( / ))eqn E T E T • Neff is ~ 3 (for standard neutrinos if non-instantaneous decoupling is considered, Neff =3.046).
Neutrino, though negligible todaywas an important constituent of the Early Universe
Effect the energy densityexpansion rateof the UniverseEffect BBN kineticsSpectrum distortionasymmetry constraintsEffect on CMB and LSSConstraints on numberof neutrino speciesConstraints on neutrino massesand number densities < 0.66 eVMatter/radiation equality shiftConstraints onoscillation parametersConstraints onsterile neutrino populationFeel total energy densitystored in neutrinosConstraints on neutrino massesConstraints on lepton asymmetrynot sensitive to different speciesor spectrum distortions
Deviations from Fermi-Dirac distribution• Electron-positron annihilation – negligible effect• Flavor oscillations Dolgov 1981 ;Mangano et al, 2005number density of one neutrino species 113 per cubic cm instead 112 in SCM.Flavor oscillations with parameters favored by the atmospheric and solar neutrino dataestablish an equilibrium between active neutrino species before BBN epoch.• Non-zero lepton asymmetry Terasawa, Sato 88; Wagoner et al.Neutrino-antineutrino asymmetry – now strongly constrained by BBN in allsectors because of flavor oscillations <0.1 Dolgov et al. 2002• Active-sterile oscillations before neutrino decoupling slightly influence activeneutrino distributions, because the states are refilled due to interactions withthe plasma and may bring sterile neutrino into equilibrium.• Active-sterile oscillations proceeding after decoupling may strongly distortneutrino energy spectrum DK, 1988; DK&Chizhov PLB 97• Decays of neutrino and into neutrinos• Violation of spin statistics, etc. Dolgov ,Smirnov ,PLB,2005; Barabash et al., 2007
Neutrinos OscillationsSolar neutrino problem, atmospheric neutrino anomalyand the results of terrestrial neutrino oscillationsexperiments were resolved by the phenomenon ofneutrino oscillations.It has been observationally and experimentally provedthat neutrinos oscillate. BSM characteristics for it hold: non-zero neutrino mass and mixing Distribution n(E) of neutrino maydiffer from the equilibrium FD form L may become considerablein resonant active-sterile oscillationsadditional species may be brought into equillibrium sterile neutrinom2 0 at least 2 neutrino with m 0m = Umf f, (f = e, , )P (, m2, E, t)Ne < Neq02393.14 eVmh 0.001 Flavor neutrino should not play an importantrole for DM (because it is HDM) and theformation of structure.Eventual sterile neutrino may be a good DMrepresentative (CDM, WDM).0.001 0.02 exp( / )/(1 exp( / ))cnb eqn n E T E T Neutrino anomalies are well described in terms of flavor neutrino oscillations, but sub-leading sterile oscillations may provide better fit.
Propagation of neutrino in early Universe• The thermal background of the early Universe influences the propagation of ν.Differences in the interactions with the particles from the plasma lead to differentaverage potentials for different neutrino types Vf f= e, μ, τNotzold&Raffelt 88 In the Sun L>>Q/M2wVf =QT3/(M2wδm2 ) -L T3 /δm2 for neutrinoVf =Q…. +L ……… for antineutrinoQ=-bET L=-aLα• In the early Universe, at E>10 MeV, Q>L if L is of the order of B.In the adiabatic case the effect of the medium can be hidden in matter oscillationparameters:In general the medium suppresses oscillations.When mixing in matter becomes maximalindependent of mixing in vacuum - enhanced oscillation transfer.for Q/M2W>L δm2 <0 resonant oscillations both for neutrino and antineutrinofor Q/M2W<L at δm2 <0 resonant for antineutrinos, δm2 >0 – for neutrinos2 2 2 2 3 2 2sin sin /[sin (( / ) / cos 2 ) ]Wm Q M L T m 2 3 2( / ) cos 2WQ M L T m
Evolution of oscillating neutrino е s 20 2( ) ( ), ( ) 2 , ( )F FWt t QHp i t i G L N t O Gt p M H *3, ,~ ~ 2 ~ /1 0exp / 1 exp /0 0e eie je i il lLL LLin eq in eqLLU U U l e sis free neutrino HamiltonianQ E T L L L L L d p Nn E T E T n 0HApproach: follow the evolution of neutrino for each momentum; account for oscillations,expansion and interactions with the medium simultaneously DK 1988, Chizhov, DK, 1997
Oscillations in the Early Universe medium• The thermal background of the early Universe influences the propagation of ν.Differences in the interactions with the particles from the plasma lead to differentaverage potentials for different neutrino types Vf f= e, μ, τNotzold&Raffelt 88 In the Sun L>>QVf =Q-L for neutrinoVf =Q+L for antineutrinoQ=-bET4 /(δm2M2W) L=-aET3Lα/(m2)• In the early Universe, E>10 MeV, Q>L if L is of the order of B.In the adiabatic case the effect of the medium can be hidden in matter oscillationparameters:In general the medium suppresses oscillations.When mixing in matter becomes maximal independent of mixing invacuum - enhanced oscillation transfer.for Q>L δm2 <0 resonant oscillations both for neutrino and antineutrinofor Q<L at δm2 <0 resonant for antineutrinos, δm2 >0 – for neutrinos2 2 2 2sin sin /[sin ( cos 2 ) ]m Q L cos 2Q L
BSM neutrino: nonequilibrium neutrino Active-sterile oscillations considerable cosmological influence Dynamical effect: Excite additional light particles into equilibrium~geffT4Fast a s effective before a decoupling - effect CMB and BBN through increasing and HHe-4 mass fraction is a strong function of the effective number of light stableparticles at BBN epoch Yd ~0.013 Ns (the best speedometer).Dolgov 81, Barbieri &Dolgov 90, Kainulainen 91, Enqvist et al.,92 Distort the neutrino energy spectrum from the equilibrium FD formDK 88, DK&Chizhov 96 Change neutrino-antineutrino asymmetry of the medium (suppress / enhance)Foot&Volkas 95,96; DK&Chizhov 96,97,2000DK&Chizhov 98,2000, Dolgov&Villante 03, DK04,07 ,DK&panayotova, 2006, DK07Active-sterile oscillations may play crucial role for neutrino involved processes inthe Universe during BBN, CMB, LSS, CNB.sN2~ TGgH eff710.75 34eff ssg N N N 2 2~ F EГ NG He-4 depends on the e characteristics: e decrease n/p freezes earlier 4Не is overproducedBBN is a sensitive probe to additional species and to distortions in the neutrinodistribution.BBN stringent limits on oscillation parameters.
• Active-sterile oscillations proceeding after decouplingmay strongly distort neutrino distribution and deplete electron neutrino.Kirilova 88, Kirilova&Chizhov PLB,972 neutrino mixing: Sterile state is filled for the sake of ePrecise description of neutrino momenta distribution:1000 bins used to describe it in non-resonant caseup to 10 000 in the resonant case.Energy spectrum distortion caused by oscillations depends on thelevel of initial population of s.Kirilova,IJMPD,20042 4 7sin 2 10m exp( / )/(1 exp( / ))eqn E T E T Nk,4 < Nk,2Flavor mixing decreases the depletion and spectrum distortion
L oscillations interplay Neutrino active-sterile oscillations change neutrino-antineutrino asymmetry of the mediumsuppress pre-existing asymmetry Barbieri&Dolgov 90.91; Enqvist et al. 1992enhance L (MSW resonant active-sterile oscillations) L-T=MKirilova&Chizhov 96; Foot&Volkas 96 -L-T=ML enhancement in MSW resonant active-sterile neutrino oscillations was first found form2>10-5eV2in collisions dominated oscillations Foot, Thompson&Volkas 96m2<10-7eV2in the collisionless case Kirilova&Chizhov “Neutrino 96”Flavor oscillations equalize L in different flavors before BBN Dolgov et al., NPB, 2002 Relic L effects neutrino oscillationssuppresses them Foot&Volkas, 95; Kirilova&Chizhov 98enhances them Kirilova&Chizhov 982( , , , ,..)m m L T In BBN with neutrino oscillations spectrum distortion and L generation lead todifferent nucleon kinetics, and modified BBN element production.
Strong influence because of the nearbyepochs in the universe historyProcesses cosmic time TGUT 10-35 s 1015 GeVInflationBA generationEW symmetry breaking 10-10 s 100 GeVQCD 10-5 s 0.3 GeVCNB formation 1 s 3 - 1 MeVBBN 1 s – 3 m 1 - 0.1 MeVCMB formation 300 000 y 0.3 eVGalaxy formation ~109 yToday 13.7 109 y 0.0003 eV~ 3K
2.8 ≤ N ≤ 3.6 (95% CL)Iocco et al, 2009Using Y from IT10:3.0 ≤ N≤ 4.5 (95% CL)Big Bang NucleosynthesisTheoretically well establishedPrecise data on nuclear processes ratesfrom lab expts at low E (10 KeV – MeV)Precise data on D, He, LiBaryon fraction measured by CMBMost early and precision probe for physical conditionsin early Universe and for new physics at BBN energies.The Best Speedometer at RDBBN probes BSM neutrino (oscillations, nonequilibrium)The Most Exact LeptometerCOSMOLOGYASTROPHYSICSMICROPHYSICS
• D is measured in high z low-Z H-richclouds absorbing light from background QSA.• He in clouds of ionized H (H II regions),the most metal-poor blue compact galaxies.• Li in Pop II (metal-poor) stars in the spheroidof our Galaxy, which have Z<1/10 000 Z ☼.The Abundances of Light ElementsD/H=(2.87±0.22) 10-5Main problem: Primordial abundances are notobserved directly (chemical evolution after BBN).Observationsin systems least contaminated by stellar evolution.D from Iocco et al. PR472, 1 (2009); He from Aver et al.2012Yp=0,2534 0,0083regression to zero ZBBN is the most early and precision cosmology probe for physical conditions in theearly Universe, and for constraining new physics, relevant at BBN energies.
According to BBN 4 light elements: D, He-3, He-4, Li-7produced during the hot stage of the Universe evolution,1 s – 3 m 1 - 0.1 MeV.10 9~10 10 KT The primordially produced abundances depend on: baryon-to-photon ratio (CMB measured now), relativistic energy density (effective number of nu)(nonst interactions, extra rel degrees of freedom, exotic physics) n lifetimeBBN is sensitive baryometer, speedometerand leptometer. BBN probes neutrino properties,non-standard physics, early UniverseBBN predictions are in agreement withobservational data for ΩB ~ 0.05.Observational data (2σ error). Vertical band give baryondensity measured by CMB.4/37 4(?)8 11X N
BBN constrains physics beyond SM• BBN depend on all known interactions - constrains modification of those• Additional light (relativistic during BBN, i.e. m< MeV) particles species(generations) effecting radiation density (H), pre-BBN nucleon kinetics orBBN itself• Additional interactions or processes relevant at BBN epoch (decays ofheavy particles, neutrino oscillations)• Depart from equilibrium distributions of particle densities of nucleons andleptons (caused by nu oscillations, lepton asymmetry, inhomogeneousdistribution of baryons, etc.)• ……………..
4Не – sensitive speedometersn 7,885e n p e epne ~MeVm 293.152~ TGГ F2~ TGgH effMeVGGgTFefff 7,0~~6/175,1047211 Ngeff61~~ fTmfepn fffnucnfnpnpnNNX1 24.0~2 ntfnp eXY ~ epnYт=(H((g)),) = 0,2482 0,0007Yо=0,256 0,01He-4 most abundantly produced (25%), most precisely measured(3-5 %) and calculated element (0.1% error), has simple post-BBN evolutionYКН~0.013 Nеff4Не is the best speedometer at BBN. Constrains additional radiation.Shvartsman 1969
BBN Speedometer2.8 ≤ N ≤ 3.6 (95% CL)Iocco et al, 2009Using Y from IT10:Yp=0,2565 0.001(stat) 0,005(syst)Izotov&Thuan, 2010 93 Sp of 86 low Z HII3.0 ≤ N≤ 4.5 (95% CL)Increasing Δ Nеff mirrors increase inYpNеff =3.53+0.66-0.63 (CMB, D)Nollett&Holder,2011
BBN constraints• Constrains the effective number of relativistic speciesNon-zero ΔNeff will indicate any extra relativistic component:like sterile neutrino, neutrino oscillations, lepton asymmetry,neutrino decays, nonstandard thermal history, etcSteigman 2012 1208.0032Y=0.2565 0.006 Δ Nеff =0.66 0.46 consistent with ΔNеff =0 95% C.L.Nеff =3.71+0.47-0.45 ΔNеff ~1 favored ΔNеff ~2 disfavored at > 95% C.L.Untill Plank CMB larger errors for ΔNeff than BBNPlanck Collaboration arXiv: 1303.5076Planck: Nеff =3.361+0.68-0.64 (95% Planck +WP+high l)Nеff =3.30+0.54-0.51 (95% Planck +WP+high l+BAO)Nеff =3.52+0.48-0.45 (95% Planck +WP+high l+H0+BAO)CMB Tension b/n H direct measurements and CMB and BAO data relievedif extra radiation exists, best fit : Nеff =3.37 (for low l power sp)4Y~0.013 Nеff
CMB+BBN simultaneous constraintsSimultaneous constraints on Y and N:Nеff =3.41+0.3-0.3 (68% Planck +WP+high l+Y(aver et al.))Nеff =3.02+0.27-0.27 (68% Planck +WP+high l+D(Pettini+Cooke))Nеff =3.33+0.59-0.83 (68% Planck +WP+high l)Yp=0.254+0.041-0.033
CMB+BAO simultaneous constraintsHowever, simultaneous constraints on Nеff and the total neutrino massor sterile neutrino mass:• massless sterileBounds tighten when BAO data are added:• massive sterile (MiniBoone, reactor and Gallium anomalies), mn=0.06 eVBounds marginally compatible with fully thermalized sterile neutrino with sub-eVmass <0.5 eV necessary to explain oscillations anomaliesL needed to suppress thermalization of the sterile neutrinoNеff =3.29+0.67-0.64 (95% Planck +WP+high l)Smn<0.60 eVNеff =3.32+0.54-0.52 (95% Planck +WP+high l+BAO)Smn<0.28 eVNеff <3.91 (95% Planck +WP+high l for thermal sterile m<10 eV)mns<0.59 eV
BBN constraintsNon-zero ΔNeff indicate lepton asymmetry: Constrains lepton asymmetrySteigman 2012 1208.0032consistent with L=0 at 1.5 s|x|<0.09 at 2 s ΔNeffL ~ <0.011 at 2 sx=0.038 0.026 allowed by He abundance, deviation from x=0 1.5 sNo new physics, no dark radiation, no LCMB not sensitive to such small L.……………………………..44 2effN =15/7[([ /T)/ ] +2[( /T)/ ] } YКН~0.013 Nеff• Constrains neutrino oscillations parametersBBN with s neutrino spectrum and densities differ, thus influencing kinetics ofnucleons in BBN epoch, reducing weak processes rates overproducing He-4.The abundance of helium is known with 5% accuracy. This allows to constrain s
Neutrino Oscillations Effects Active-sterile oscillations a s may have considerable cosmologicalinfluence! Dynamical effect: Excite additional light particles into equilibrium~geffT4Fast a s effective before a decoupling - effect CMB and BBN through increasing and HHe-4 mass fraction is a strong function of the effective number of light stableparticles at BBN epoch Yd ~0.013 Ns (the best speedometer).Dolgov 81. DK 88, Barbieri, Dolgov 90, Kainulainen 91, Enqvist et al.,92 Distorting the neutrino energy spectrum from the equilibrium FD formDK 88, D.K&Chizhov,96 Change neutrino-antineutrino asymmetry of the medium (suppress / enhance)D.K&Chizhov,96; Foot&Volkas 95,96; Shi 96; di Bari 2003; DK 2012DK&Chizhov 98,2000, Dolgov&Villante 03, DK04,07;DK&Panayotova 06 ;Panayotova 2011, DK 20122~ TGgH eff710.75 34eff ssg N N N 2 2~ F EГ NG He-4 depends on the e characteristics: e decrease n/p freezes earlier 4Не is overproducedBBN is a sensitive to additional species and to distortions in neutrino distributionBBN stringent limits on oscillation parameters. Flavor Matter Oscillations favored by the atmospheric and solar neutrino dataestablish an equilibrium between active neutrino species before BBN epoch.No considerable influence on BBN, CMB, CNB.Account for flavor oscillations : 113 /cm3 instead 112 in SCM. But might be important for L.
Sterile neutrinos may be present at the onset of BBN epoch - may be produced in GUT models, in models withlarge extra dimensions, Manyfold Universe models, mirror matter models, or by oscillations in 4-neutrino mixingschemes, etc. The degree of population may be different depending on the production model.The distortion due to active-sterile oscillations and the kinetic effect caused Nkdepends on the degree of initial population of s. The biggest effect Nk,0 is achievedfor Ns=0, the effect decreases with Ns .Nk ~ Nk,0- Nk,0 NsSpectrum distortion for non zero initial popuation of sSpectrum distortion for different initial population of s.:Ns=0 – lowest curve, Ns=0,5 and Ns=0,8 – upper curve.The dashed curve shows the equilibrium spectrum.DK,Int.J.Mod.Phys.D,2004Ns=0,8Ns=0,5Ns=0Due to nonequilibrium oscillations the numberdensity of neutrinos are depleted and theirdistribution differ from equilibrium FD one.
Maximum He-4 overproduction in BBN with active-sterileneutrino oscillations may be much bigger than 5% due tokinetic effects.BBN with nonequilibrium es allows toconstrain oscillation parameters forHe-4 uncertainty up to 32% (14%) in resonant(non-resonant) case.BBN with ne ns leads to max 4Не overproduction32% in the resonant case (13% in the non-resonant)i.e. 6 times stronger effect than the dynamicaloscillations effect. DK , Astrop.Phys.,2003 The kinetic effects of oscillations depend on the initialpopulation of neutrino due to interplay b/n effectsRole of sterile neutrino: dynamical effect– increasing Н(g)suppressing the osc kinetic effectN= Nk,0- Nk,0 Ns +Ns
He-4 is the preferred element: abundantly produced, precisely measured precisely calculated (0.1% uncertainty)Yp=0,2482 0,0007 has a simple post-BBN chemical evolution best speedometer and leptometer sensitive to neutrino characteristics (n, N, sp,LA..)Fit to BBN constraints corresponding to Yp/Yp=3%:BBN with nonequilibrium oscillations leads up32% He overproduction, i.e. N<9.BBN with oscillations may provide the excess density.BBN constraints on e sDK, Chizhov NPB2000,2001; 42 2 9 2 22 10 2 2sin 2 1.5 10 08.2 10 large , 0m eV mm eV m Yp=0,2565 0.001(stat) 0,005(syst)Izotov&Thuan, 2010 93 Sp of 86 low Z HII
BBN constraints on oscillationsBBN with neutrino oscillations between initially empty s and eBarbieri, Dolgov 91 – depletion accountDolgov 2000 – dashed curve;DK, Enqvist et al. 92 – one p approx.Dolgov, Villante, 2003 - spectrum distortion 22 4 5 222 4 5 2sin 2 3.16 10sin 2 1.74 10es ess sm eV Nm eV N DK.,Chizhov 2001 – distortion andasymmetry growth account 42 2 9 2 22 10 2 2sin 2 1.5 10 08.2 10 large , 0m eV mm eV m BBN constraints are by 4 orders of magnitude more stringent than experimental ones Excluded 2 of the possible solutions of the solar neutrino problem : LMA and LOW active-sterilesolutions (1990, 1999)years before experimental results. Excludes electron-sterile solution to LSND2 4 7sin 2 10m BBN constraints on е s :m2>10-6 eV2
BBN constraints relaxed or strengthened?Additional s population may strengthen or relax BBN constraints.Yp/Yp=5.2%Dotted blue (red) contour presents Yp/Yp=3% (Yp/Yp=5.2% )for Ns=0 dotted curve, solid - Ns=0,5.Due to interplay b/n the effects ofnon-zero initial population of s (partiallyfilled) on BBN,BBN bounds change non-trivially with Ns:In case the dynamical effect dominates,He-4 overproduction is enhanced andBBN constraints strengthen.In case the kinetic effect dominates He-4overproduction decreases with Ns increase andBBN constraints relax.Yp=0,2565 0.001(stat) 0,005(syst)Izotov&Thuan, 2010 93 Sp of 86 low Z HIIYth=0,2482 0,0007DK&Panayotova JCAP 2006;DK IJMPD 07,Panayotova 2011;DK,2011Constraint contours for 3 and 5% He-4 overproduction
Lepton AsymmetryLepton asymmetry of the Universemay be orders of magnitude bigger than the baryon one,Though usually assumed L~, big L may reside in the neutrino sector(universal charge neutrality implies Le=) .CNB has not been detected yet, hence L may be measured/constrained only indirectlythrough its effect on other processes, which have left observable traces in the Universe:light element abundances from Big Bang Nucleosynthesis , CMB, LSS, etc.Wagoner et al.1967….Terasawa&Sato, 1988 …Dolgov,2002Serpico&Raffelt, 2005; Pastor, Pinto&Raffelt,2009; Simha&Steigman, 2008Lesgourgues&Pastor,1999; Shiraishi et al., 2009; Popa&Vasile, 200810( )/ ~ 6.10b bn n n ( )/l lL n n n 33 231( )12 (3)ii iiTLT /T ~iiL L
Lepton Asymmetry Effects• Dynamical - Non-zero L increases the radiation energy densityleading to faster expansion H=(8/3G)1/2, delaying matter/radiation equality epoch …influence BBN, CMB, evolution of perturbations i.e. LSS• Direct kinetic - |Lne|> 0.01 effect neutron-proton kineticsin pre-BBN epochinfluence BBN, outcome is L sign dependentSimha&Steigman, 2008:• Indirect kinetic - L 10-8 effects neutrino evolution, its number density, spectrumdistribution, oscillations pattern and hence n/p kinetics and BBNDK&ChizhovNPB98,2000;DK PNPP, 2010, 2011, DK JCAP,2012.• L changes the decoupling T of neutrino, etc.4 2effN =15/7(( / ) +2( / ) ) e n p e epne ~~ epn10~ (0.2482 0.0006) 0.0016 0.013 0.3 ep effY N
BBN Constraints on L BBN provides the most stringent constraint on LIn case neutrino oscillations degeneracies equilibratedue to oscillations before BBNDolgov et al., NPB, 2002Serpico&Raffelt,2005 roleIocco et al.,2009 Accounting for flavor oscillations and ν decouplingand Miele et al.,2011 Steigman, 2012 recent analysis|x|<0.09 at 2 s consistent with L=0 at 1.5 sx=0.038 0.026 allowed by He abundance, deviation from x=0 1.5 s CMB and LSS provide looser boundsL(x) modifies the power spectra of radiation and matter Lesgourgues&Pastor, 99Popa&Vasile , 2008 forcast for Planck:Interplay between L and active-sterile oscillations allows to constrain strongly L.| | 0.1 213sin 0.03 0.1L
Asymmetry - OscillationsInterplay Neutrino active-sterile oscillations change neutrino-antineutrino asymmetry of the mediumsuppress pre-existing asymmetryBarbieri&Dolgov 90.91; Enqvist et al. 1992enhance L (MSW resonant active-sterile oscillations) L-T=M-L-T=ML enhancement in MSW resonant active-sterile neutrino oscillations was first found form2>10-5eV2in collisions dominated oscillations Foot&Volkas 96m2<10-7eV2in the collisionless case Kirilova&Chizhov 96 Asymmetry effects neutrino oscillationssuppresses themFoot&Volkas, 95; Kirilova&Chizhov 98enhances themKirilova&Chizhov 98 ; Kirilova 2010, 20122( , , , ,..)m m L T
We studied the interplay between small L and neutrino oscillations in the earlyUniverse and their effect on BBN for the specific case:effective after active neutrino decouplingSmall L<<0.01 influence indirectly BBN via oscillations by: changing neutrino number densities changing neutrino distribution and spectrum distortion changing neutrino oscillations pattern (suppressing or enhancing them)L effect in density and direct effect in n-p kinetics – negligible• Different cases of L were studied:relic initially present L>10-10 and dynamically generated by oscillations1 = ecos + ssin2 = - esin + scos2 4 7sin 2 10m eV2Foot&Volkas 97, Bell,Volkas&Wang,99DK&Chizhov , NPB 96, 98, 2001 DK PNPP 2010The evolution of the L was numerically studied. L influence on oscillations was exploredin the full range of model oscillation parameters and a wide range of L values.Primordial production of He-4 was calculated. Modified BBN constraints on oscillationparameters in presence of L were presented.
Evolution of neutrino in presence ofе s oscillations and L• Equations governing the evolution of the oscillating and s , accountingsimultaneously for Universe expansion, neutrino oscillations and neutrino forwardscattering. 20 2( ) ( ), ( ) 2 , ( )F FWt t QHp i t i G L N t O Gt p M H 20 2( ) ( ), ( ) 2 , ( )F FWt t QHp i t i G L N t O Gt p M H *3, ,~ ~ 2 ~ /1 0exp ( )/ 1 exp ( )/0e eie je i il lLL LLin eq in eqLLsU U U l e sis free neutrino HamiltonianQ E T L L L L L d p Nn E T E T nN 0H710.75 34eff ssg N N N Non-zero L term leads to coupled integro-differential equations and hard numerical task .L term leads to different evolution of neutrino and antineutrino.
Evolution of nucleons in the presence of е s)()(),,(2LLnpennnpnnnnpeApedpnHptn )()~()~,,(2LLpnennnpneAped 2 7 210 0 12 0.3sm eV all mixing angles NMeV T MeV Oscillations and L dynamical andkinetic effect on BBN were explored.Y ~0.013 NN= Nk,0- Nk,0 Ns +Ns In BBN with e s and L neutrino spectrum distortion and the density of electronneutrino may considerably differ from the standard BBN one, leading to different nucleonkinetics, and modified BBN element production.10-10<L<0.01BBN with е s and L
Oscillations generated L and BBNFor m2sin42 <10-7eV2evolution of Lis dominated by oscillations and typicallyL has rapid oscillatory behavior.The region of parameter space for whichlarge generation of L is possible:Generation of L up to 5 orders of magnitudelarger than is possible, i.е. L~10-5evolution.2 0.5sin 2 10 25.942102sin|| eVm L(t)m2~10-8.5eV2 In BBN with e s neutrino spectrum distortionand asymmetry generation lead to different nucleonkinetics, and modified BBN element production.)()(),,(2LLnpennnpnnnnpeApedpnHptn )()~()~,,(2LLpnennnpneAped 2 7 210 0 12 0.3sm eV all mixing angles NMeV T MeV -3,0 -2,5 -2,0 -1,5 -1,0 -0,5 0,00,130,140,150,160,17m2=108.65eV2Xnlog(sin22)m2=107eV2Xn and correspondingly the primordially producedHe-4 decreases at small mixing parameters valuesdue to asymmetry growth.DK, PNPP,2010; 2011
Effect of dynamical L and distortion of е distribution on constraintsThus, if the mixing is small the generated asymmetry may partially suppressthe oscillations and the inert neutrino may equilibrate only partially . The account of the neutrino-antineutrinoasymmetry growth caused by resonantoscillations leads to relaxation of theBBN constraints for small mixings. The spectrum distortion leads to a decreaseof the weak rates, to an increase of the n/pfreezing T and He overproduction.Correspondingly the account of spectrumdistortion leads to strengthening of BBNconstraints at large mixings by orders ofmagnitude.Oscillations change energy spectrum distribution and the number densities of е fromstandard BBN case. This influences the kinetics of nucleons during BBN and changes theproduced light element abundances.Ns=0
Relic L and BBN with oscillationsBBN with oscillations is the best known leptometer.suppresses oscillationsinhibit oscillations.L change primordial production of Heby enhancing or suppressing oscillations.2 2/30.1( )L m2 2/3( )L m 2, ,pY m L Lepton asymmetry may relax BBN constraintsat large mixings and strengthen them at smallmixing. DK&ChizhovNPB98, Kirilova JCAP 2012DK, JCAP 2012 BBN with oscillations can feel extremely small L: down to 10-82 2 3/2( )m eV L
Cosmological indications suggesting additional relativistic density:NBBN=3.8+0.8-0.7 NCMB=4.34+/- 0.87 NSDSS=4.78+1.89-1.79Y=0.2565+/-0.001+/-0.005 WMAP7+BAO+HST Komatsu et al. 2011A IT2010 68% CL 95% confidenceY=0.2561+/-0.01 Aver et al. 2010WMAP7+BAO+HST+ACT Keisler et al. 2011: 3.86+/-0.42+SPT Dunkley et al. 2011 4.56+/-0.75Neutrino oscillations expts indicationsΔNeff measures any relativistic component, including inertneutrino brought into equlibrium, oscillations, LA, decays,etc.CMB recent data does not require DR. Neutrino exp data analysis point to 3+1, do notneed 3+2 models anymore, in light of recent expt results.
Fruitful interplay b/n cosmology and particle physics exists. Cosmology can predict the influence of BSM neutrino characteristics and test them. Inparticular, it «measures» total neutrino mass, number of neutrino species, neutrinohierarchy (hopefully), neutrino oscillations patameters, deviations from equilibrium, .. In case of active-sterile oscillations effective after decoupling of active neutrinosthe number densities of CNB neutrinos may be reduced, the spectrum distorted BBN is very sensitive to neutrino spectrum distortion and lepton asymmetry.BBN constraints on oscillations parameters in case of non-equilibrium oscillationsdo exist even if He-4 uncertainty were over 5%. Spectrum distortion plays a majorrole in the influence of neutrino oscillations on BBN.BBN provides the most stringent constraint on m2 .BBN bounds on Neff is strengthened in case of neutrino oscillations. BBN constraints on neutrino oscillations parameters depend nontrivially on thepopulation of sterile neutrino and L in the Universe.BBN bounds on L depend on the presence of neutrino oscillations. Theystrengthen considerably in case of presence of active- sterile neutrino oscillations.BBN bounds on Neff is strengthened in case of neutrino oscillations.• Additional initial population of the sterile state not always leads to strengthening ofconstraints (as can be naively thought) it may also relax them.SummaryCosmology Tests and Predictions of BSM neutrino characteristics
Considerable L generation in active-sterile Mikheyev-Smirnov-Wolfensteinoscillations, effective after neutrino decoupling, is found. The region in the oscillationparameter space of considerable L growth was determined. Small lepton asymmetry LA << 0.01, either relic or generated by active-sterileneutrino oscillations, which do not have direct effect on nucleons kinetics duringBBN, may have considerable cosmological influence. Such small asymmetries areinvisible by CMB, but may be felt by BBN: L as small as 10-8 may be felt by BBNvia oscillations. The effect of the dynamically generated and initially present L on BBN withoscillations was studied. Lepton asymmetry is able to enhance, suppress or inhibitoscillations. The parameter range for which relic L is able to enhance, suppress orinhibit oscillations is determined. L provides relaxation or enhancement of BBN constraints on oscillations.Large enough L alleviates BBN constraints on oscillation parameters.3+1 oscillations models may be allowed by BBN with L, because large enough Lprovides relaxation of BBN constraints, suppressing oscillations and leading toincomplete thermalization and relaxation of limits on inert neutrino.Summary
Благодаря за вниманието!Thanks for the attention!
Accelerated expansionSometime around 5 billion years ago, the universebegan accelerating - its expansion getting fasterand faster, rather than gradually slowing down.Ordinary matter gravitates.Antigravity requires unusual medium with p < 0 andCombined results from CMB, BAO, SN point to the presence of DM and DE.p/ = ω < -1/3
Planck 2013 resultsarXiv:1303.5062Planck and BSM neutrino physics:No evidence for extra relativisticneutrino species
No compelling evidence fornon-standard numberof neutrino species
Sterile Neutrinos Status• Sterile neutrino is not constrained by LEP• Required for producing non-zero neutrino masses by most models• Predicted by GUT models• Hints from oscillations data: for better fit subdominant sterile oscillationschannel required by Homestake data, Holanda, Smirnov, 2004), Chauhan,Pulido, 2004, variation of the flux with B, Caldwell D, Sturrock P.,2005• required for explanation of LSND in combination with other expts• Wellcomed by cosmology:* may be the particle accounting for all DM (m<3.5 KeV if MSM produced)* may play subdominant role as DM component (eV, KeV)* Fast moving neutrinos do not play major role in the evolution of structurein the universe.* may play a role in LSS formation (when constituting few % of the DM itsuppresses small scale power in the matter power spectrum and better fitsthe observational data from SDSS, cluster abundance, weak lensing, LymanAlpha forest, CMB) Tegmark et al., 2004*plays major role in natural baryogenesis through leptogenesis
Effects of nonequilibrium a sKinetic effects: and e energy spectrum distortion, e depletion, D.K.,1988; Barbieri,Dolgov, 1990,91Enqvist et.al., 92; DK M.Chizhov, PLB ,1996,97 energy threshold effect pre-BBN kinetics neutrino-antineutrino asymmetry growth Foot, Volkas,1996; DK M.Chizhov,1996Dolgov et al., 2002In case of oscillations effective after decoupling and provided that the sterile state is not inequilibrium (Ns<1), kinetic effect on BBN dominate for wide range of oscillation parameters. Interms of effective number of neutrinos: Nk,0 6 res.osc., Nk,0 3 nonres.DK , Astrop.Phys.,2003Kinetic effects and should be appropriately described.2~oscmГE)(~ 2EndEEN 2 2~ FEГ NG
BBN SummarySpectrum distortion plays a major role in the influence of neutrino oscillations on BBN.For oscillations after neutrino decoupling it leads up to 6 times higher helium overproductionthan the dynamical effect of an additional neutrino state.Distortion decreases with the increase of the initial population of the sterile neutrino, thekinetic effect decreases correspondingly.Helium may be both overproduced or underproduced with the increase of the initialpopulation of s depending which effect dominates (dynamical or kinetic).Additional partially filled sterile state may lead to strengtheningas well as to relaxation of the BBN constraints.BBN with nonequilibrium e s oscillations allows to put constraintson oscillation parameters for He-4 uncertainty up to 32%(14%) in resonant(non-resonant) case, provided s was not in equilibrium, which correspondsto N<9.At large mixing BBN constraints strengthen by orders of magnitude whendistortion effect of oscillations is accounted for, at small mixings they are relaxeddue to oscillations generated asymmetry in the resonant case.Flavor mixing account will lead to a decrease of the spectrum distortion effectand relaxation of the constraints.
58/27- Planck satellite will reach a sensitivity for Neff of the order of 0.4 at 2σ- A detection of a ΔNeff = 0.4 – 0.5 could imply a large degeneracy butonly for almost vanishing θ13, but in this case a measurement of suchangle larger than almost 0.03 would mean extra d.o.f.- A detection of a ΔNeff > 0.5 would mean in anycase extra d.o.f.- We have a robust limit from BBN: ΔNeff ≤ 1.2 at 2σ arXiv:1103:1261v1[astro-ph.CO]
Sterile Neutrinos StatusSterile – that does not couple to standard model W or Z boson.Hints for sterile from tension with 3 neutrino paradigm: LSND, MiniBooNE,reactor expts (10-100m), Cr and Ar solar neutrino detectorscosmology hints: CMB and BBN and LSS• Wellcomed by cosmology:• may play subdominant role as DM component (eV, KeV)• may play a role in LSS formation (when constituting few % of the DM itsuppresses small scale power in the matter power spectrum and better fitsthe observational data from SDSS, cluster abundance, weak lensing, LymanAlpha forest, CMB)• plays major role in natural baryogenesis through leptogenesis• The X ray photons from sterile neutrino decays may catalize the productionH2 and speed up the star formation, causing earlier reionization –observational feature predicted to search with X-ray telescopes• Pulsar kicks from anisotropic SN emission• Sterile neutrino is constrained by BBN, because it increases the expansionrate and hence dynamically influences He production, in case it is broughtinto equilibrium, its decoupling temperature must be TR > 130 MeV.• In case of oscillations with active neutrino it exerts major effect onexpansion rate and nucleons kinetics during pre-BBN and its mixingparameters are constrained by BBN+CMB• Et cetera…..
He-4 is the preferred element: abundantly produced, precisely measured precisely calculated (0.1% uncertainty)Yp=0,2482 0,0007 has a simple post-BBN chemical evolution best speedometer and leptometer sensitive to neutrino characteristics (n, N, sp, L..)BBN with nonequilibrium oscillations leads upto 32% He overproduction, i.e. N<9.BBN constraints on the basis of the He-4 data in case proper account for spectrum distortion, δNsand asymmetry growth due to oscillations were obtained.BBN constraints, accounting for L, on e sBarbieri, Dolgov 91 – depletion accountEnqvist et al. 92 – one p approx.Kirilova, Chizhov 97, 2000 spectrum distortion and L growthaccountDolgov, Villante, 2003 - spectrum distortionKirilova, Panayotova, 2006 – δNs effectKirilova, 2010, 2012 – relic L and oscillations generated LYp=0,2565 0.001(stat) 0,005(syst)Izotov&Thuan, 2010 93 Sp of 86 low Z HIIAdditional inert population may strengthenor relax BBN constraints.
The dependences of helium production on m2(for different L) .lgL=-10logm2lgL=-6lgL=-5Kirilova JCAP 2012Relic L and BBN with neutrino oscillations2sin 2 1 lgLThe dependences of helium production on relic L(for different mixing) .
Hamman et al. 2012:Cosmological data show slight preferencefor extra radiation, but 3+2 difficult in LCDMdeviations from minimal modelchange in matter density, L ………….
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