Neutrinos and Astrophysics

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1 Neutrinos and Astrophysics Astrophysical neutrinos Solar and stellar neutrinos Supernovae High energy neutrinos Cosmology Leptogenesis Big bang nucleosynthesis Large-scale structure and CMB Relic neutrinos

2 Astrophysical Neutrinos Simultaneous probes of ν and astrophysics Big Bang neutrinos 300 ν s/cm 3 left over from big bang Leptogenesis? Big bang nucleosynthesis (to 7 Li) Important for dark matter? Detection?

3 Solar/stellar neutrinos Nuclear reactions in core, nucleosynthesis (to F e) Depletion and spectral distortion neutrino mass/oscillations Astrophysics vs neutrino properties Bounds on magnetic moments/non-standard properties Supernova neutrinos (SN1987A) Core collapse into neutron star ν e pulse from e p ν e n Fireball of ν + ν boils off for 10 sec ν s may revive shock, affect r-process (nucleosynthesis above F e), pulsar kicks? (Too light?) Oscillation/conversion constraints and supernova probes

4 CDHSW Atmospheric neutrinos Cosmic rays in atmosphere produce π s π + µ + ν µ, µ + e + ν e ν µ Expect µ/e 2, observe 1.2 Zenith angle: disappearance (oscillation) High energy neutrinos m 2 [ev 2 ] KARMEN2 SMA LSND Bugey CHOOZ LMA CHORUS NOMAD NOMAD CHORUS BNL E776 SuperK KamLAND PaloVerde Active galactic nuclei, gamma ray bursts, supernova shocks? Z bursts (detection of relic; cosmic rays above GZK)? 10 9 ν e ν X ν µ ν τ ν e ν τ ν e ν µ VAC LOW tan 2 θ 10 2

5 Solar and stellar neutrinos Produced during stellar nucleosynthesis Energy loss constraints (globular clusters, horizontal branch, ) Core collapse supernovae

6 Solar neutrinos + Kamland confirmed SSM (also helioseismology) Established LMA Excluded sterile, RSPF, new interactions as dominant

7 s -1 ) 6 cm -2 (10 φ µτ SNO φ ES SK φ ES SNO φ CC SNO φ NC φ SSM φ (10 cm -2 s -1 e )

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9 β < cos2θ 12 Future pp experiment P ee sin 2 2θ 2 12 β > 1 Stellar evolution theory at 1% U e3 probe sin 2 θ 12 MSW/vacuum transition 0.2 Constrain sterile, axions, 0.0 E ν

10 Stellar energy loss severely constrains anomalous energy loss, e.g. heavy Dirac, anomalous electromagnetic moments, decays Simplest models: µ ν = µ B (m ν /ev )

11 Magnetic or Electric Moments Motivated by alternative RSFP Solar ν solution Transition (Majorana); transition or direct (Dirac) He ignition in globular cluster red giants (plasmon decay): µ ν < µ B (all types) Supernova cooling: µ ν (Dirac) < µ B Radiative decays Neutrino Decays Radiative, ν 2 ν 1 γ: diffuse background from relic ν s; SN1987A radiation Invisible decays (e.g., into Majorons): matter fraction and growth of structure Was mainly relevant for heavier neutrinos, now excluded by oscillations

12 Supernovae Collapse of iron core of M > 8M star 99% of energy ( > ergs) radiated in neutrinos

13 Neutronization pulse: e p ν e n (ms) Bounce and expanding shock. Stalls in simulations. Neutrinosphere radiates ν i + ν i for 10 s ν e observed for SN1987A

14 Neutrinos probe supernova dynamics Basic picture verified by 1987A Expect thousands of events for galactic SN ( yr) Keep detectors running for 50 yr! SNEWS: The SuperNova Early Warning System Sensitive to obscured or failed supernovae! Experiments becoming sensitive to diffuse SN ν s from other galaxies

15 Probe of neutrino properties m νe < 20 ev from 1987A m i < 10 s ev (future), but now irrelevant SN1987A energetics may disfavor inverted if U e3 0 (hardened ν e spectrum) Limits on energy loss, e.g. for LED, Z N R N R, large Dirac masses, millicharge, µ ν (Dirac) New interactions (e.g. Majoron models) Future (including Earth effect): sensitive to oscillation patterns

16 Neutrinos may affect supernova dynamics Massive neutrinos could revive stalled shock, but not for standard 3 ν scheme r-process not prevented by ν µ ν e and ν e n e p for standard 3ν Heavy sterile conversion could help r-process by removing active ν s to prevent ν e n e p Pulsar kick mechanism for 1-20 KeV sterile

17 High energy neutrinos Probe of ultra high energy sources (GRB, AGN, BH, SN) Probe of ultra high energy νn interactions (e.g., anomalous in LED) Probe of neutrino properties (oscillations into ν τ ), mass hierarchy, decays, moments Earth tomography?

18 IceCube Antares

19 ν COSMIC RAY The Z burst scenario: possible probe of relic ν for m ν < ev: ν(uhe) ν(relic) Z hadrons D GZK ~50 Mpc Z ν RELIC } 0 10 π 20 γ 2 nucleons 17 π - + e + -,ν,ν Depends on (unknown) large flux of ultra HE ν s

20 Cosmic ray events with E p > GZK cutoff? (or energy calibration?) (Best fit m ν = ev, Fodor, Katz, Ringwald) Future: Auger project

21 Cosmology Leptogenesis Big bang nucleosynthesis Large-scale structure and CMB Relic neutrinos

22 Leptogenesis Baryon asymmetry n B /n γ Basic ideas worked out by Sakharov in 1967, but no concrete model 1. Baryon number violation 2. CP violation: to distinguish baryons from antibaryons 3. Nonequilibrium of B-violating processes

23 Possible mechanisms GUT baryogenesis (wiped out by sphalerons for B L=0) Electroweak baryogenesis (easier with U(1) ) Leptogenesis (heavy Majorana N decays) (involves new CP phases) Out of equilibrium decays created lepton asymmetry N heavy l + Higgs N heavy l + Higgs Electroweak tunneling (actually thermal fluctucation) then converts some of the lepton asymmetry into a baryon asymmetry! Difficulties in supersymmetric version: gravitino problem suggests reheating temperature too low (unless N heavy produced nonthermally)

24 Big bang nucleosynthesis Production of light nuclei ( 4 He, D, 3 He, 7 Li) in early Universe Parameters η = n B /n γ (η Ω b h 2 ) N ν (any new source of energy density, relative to one active ν flavor) ξ e = µ νe /T, related to (n νe n νe )/n γ SBBN: N ν = ξ e = 0

25 ν e n e p and e + n ν e p keep n n /n p in equilibrium as long as it is rapid enough Freezeout at T 1 MeV, when Γ weak H Γ weak = cg 2 F T 5 H = [ 8π 3 G Nρ ] 1/2 1.66g 1/2 T 2 /M P l g = g B g F, with g F = N ν ( ) 1/3 T n n n p g 1/2 G 2 F M P l = e (m n m p +µ ν e )/T 4 He 4 He mass fraction: Y p = 4n 4 He depends strongly on N n ν H ( Y p N ν ) and ξ e, weakly on η Y 2 = D depends on η (baryometer) H Independent determination of η from CMB

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27 Central 4 He somewhat low Best fit for N ν < 0, but consistent with zero Most new physics yields N ν > 0 strongly constrained Z ν R ν R ; sterile neutrinos (LSND); ξ µ,τ Can compensate by ξ e 0.1; naively expect 10 10

28 δm m 2 /ev ν ν e s LMA ν ν µ,τ s ATM Exclusion on sterile for N ν < sin 2 2θ sin θ0 Compensation of ξ e and N ν

29 Large-scale structure (LSS) and CMB Hot Dark Matter (HDM) Ω ν h 2 = l m ν i /92.5 ev HDM excluded by free-streaming: not enough time for large structures to fragment Mixed CHDM models, typically Ω matter 1 and i m ν i few ev motivated degenerate ν spectra Now excluded by (a) Ω matter 0.3 (clusters, etc); (b) Ω total = Ω DE +Ω matter 1, DE = dark energy (1st CMB peak, WMAP); (c) Ω DE 0 (Type Ia supernovae)

30 Small admixture of HDM still possible LSS (2dF, SDSS) sensitive to Σ ν i m ν i CMB (WMAP) fixes other (degenerate) parameters Current: Σ ν < ev m νi < 0.3 ev 6000 CMB TT power spectrum l(l + 1)C l / 2π [µκ 2 ] P g (k) [(h -1 Mpc) 3 ] Multipole l k [h/mpc] Σ ν = 0.28 ev (solid), 1.5 ev (dotted), 3.0 ev (dashed)

31 Current: Σ ν < ev m νi < 0.3 ev Future: sensitive to 0.1 ev, weak lensing, LSS, CMB cf. tritium β decay: m ν < 2.4 ev (future: KATRIN, 0.3 ev) cf. ββ 0ν < few 10 1 ev (future: 0.02 ev)

32 CMB has some sensitivity to N ν (matter-radiation transition) Warm dark matter (e.g. 10 kev decaying ν) may still be viable

33 Relic neutrinos ν i, ν i decoupled at T D few MeV, while still relativistic Subsequently, p redshifted to p = p /η, where η R(t)/R(t D ) Now have form of relativistic thermal distribution, with T ν T D η = ( ) 4 1/3 Tγ 1.9K, and m 11 effi m i η m i

34 For hierarchical pattern m ev, m ev, m 1 m 2 ( v , v ) For degenerate pattern, m 1 m 2 m < ev (WMAP), ( ) v i ev m i Clustering? v esc 10 4 (Sun), (Galaxy), (Large Cluster) Little effect on velocities except degenerate case Little clustering unless m i > 0.3 ev, and then on supercluster scale

35 Indirect detection: effects of BBN, LSS Direct detection? Incoherent scattering? Impossible Coherent effects (forces, torques)? Impossible Z-burst: only known plausible mechanism, but only if flux of ultra high energy ν

36 Conclusions (From Neutrino Facilities Assessment Committee report (NAS 2002))