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Neutrino Physics. Hitoshi Murayama (Berkeley + I P M U ) NNN 2007, Hamamatsu Oct 3, 2007. Outline. Past: Why Neutrinos? Present: Era of Revolution Near Future: Bright Prospect Big Questions: Need Synergies Astrophysical Probe Conclusion. Past. Why Neutrinos?.
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Neutrino Physics Hitoshi Murayama (Berkeley+IPMU) NNN 2007, Hamamatsu Oct 3, 2007
Outline • Past: Why Neutrinos? • Present: Era of Revolution • Near Future: Bright Prospect • Big Questions: Need Synergies • Astrophysical Probe • Conclusion Murayama, NNN 2007
Past Why Neutrinos?
Probe to High Energies • Effects of physics beyond the SM as effective operators • Can be classified systematically (Weinberg) Murayama, NNN 2007
Unique Role of Neutrino Mass • Lowest order effect of physics at short distances • Tiny effect (mn/En)2~(0.1eV/GeV)2=10–20! • Inteferometry (i.e., Michaelson-Morley) • Need coherent source • Need interference (i.e., large mixing angles) • Need long baseline Nature was kind to provide all of them! • “neutrino interferometry” (a.k.a. neutrino oscillation) a unique tool to study physics at very high scales • Not entirely surprising (in retrospect) that neutrino mass was the first evidence for physics beyond standard model Murayama, NNN 2007
Ubiquitous Neutrinos They must have played some important role in the universe! Murayama, NNN 2007
Astrophysical Probe • Neutrinos unhindered by the entire star, dusts, CMB, galactic & intergalactic B, even last rescattering surface • Possible probe into • Core of stars (Sun, supernovae, GRB) • Near blackholes (AGN) • Dark Matter (Sun, galactic center, subhalo) • Cosmology? Murayama, NNN 2007
Present Era of Revolution
excluded? The Data Evidence for oscillation: • “Indisputable” • Atmospheric • Solar • Reactor • “strong” • Accelerator (K2K) And we shouldn’t forget: • “unconfirmed” • Accelerator (LSND) Murayama, NNN 2007
2/dof=839.7/755 (18%) m2=2.510-3 eV2 sin22=1 SuperKamiokande Atmospheric disappear Downwards ’s don’t disappear 1/2 of upwards ’s do disappear Murayama, NNN 2007
SNOSolar transform in flavor 2/3 of e’s Murayama, NNN 2007
TAUP 2007, preliminary KamLANDReactor neutrinos do oscillate! Proper time L0=180 km Murayama, NNN 2007
What we learned • Lepton Flavor is not conserved • Neutrinos have tiny mass, not very hierarchical • Neutrinos mix a lot the first evidence for demise of the Minimal Standard Model Very different from quarks Murayama, NNN 2007
The Big Questions • What is the origin of neutrino mass? • Did neutrinos play a role in our existence? • Did neutrinos play a role in forming galaxies? • Did neutrinos play a role in birth of the universe? • Are neutrinos telling us something about unification of matter and/or forces? • Will neutrinos give us more surprises? Big questions tough questions to answer Murayama, NNN 2007
Immediate Questions • Dirac or Majorana? • Absolute mass scale? • How small is q13? • CP Violation? • Mass hierarchy? • Is q23 maximal? Murayama, NNN 2007
Future Bright Prospect
Immediate Questions • Dirac or Majorana? • Absolute mass scale? • How small is q13? • CP Violation? • Mass hierarchy? • Is q23 maximal? Murayama, NNN 2007
Extended Standard Model • Massive Neutrinos Minimal SM incomplete • How exactly do we extend it? • Abandon either • Minimality: introduce new unobserved light degrees of freedom (right-handed neutrinos) • Lepton number: abandon distinction between neutrinos and anti-neutrinos and hence matter and anti-matter • Dirac or Majorana neutrino • Without knowing which, we don’t know how to extend the Standard Model • KATRIN, 0, Large Scale Structure Murayama, NNN 2007
Immediate Questions • Dirac or Majorana? • Absolute mass scale? • How small is q13? • CP Violation? • Mass hierarchy? • Is q23 maximal? Murayama, NNN 2007
T2K (Tokai to Kamioka) Murayama, NNN 2007
Immediate Questions • Dirac or Majorana? • Absolute mass scale? • How small is q13? • CP Violation? • Mass hierarchy? • Is q23 maximal? • LSND? Sterile neutrino(s)? CPT violation? Murayama, NNN 2007
LMA confirmed by KamLAND • Dream case for neutrino oscillation physics! • Dm2solar within reach of long-baseline expts • Even CP violation may be probable • Possible only if: • Dm122, s12 large enough (LMA) • q13 large enough Murayama, NNN 2007
q13 decides the future • The value of q13 crucial for the future of neutrino oscillation physics • Determines the required facility/parameters/baseline/energy • sin22q13>0.01conventional neutrino beam • sin22q13<0.01 storage ring, beam • Two paths to determine q13 • Long-baseline accelerator: T2K, NOA • Reactor neutrino experiment: 2CHOOZ, Daya Bay Murayama, NNN 2007
32-plane block Admirer NOAFermilab to Minnesota 25kt NOnA MINOS L=810km Murayama, NNN 2007
Far site 1600 m from Ling Ao 2000 m from Daya Overburden: 350 m 910 m Mid site ~1000 m from Daya Overburden: 208 m 570 m 730 m 230 m 290 m Daya Bay Near 360 m from Daya Bay Overburden: 97 m Daya Bay Empty detectors: moved to underground halls through access tunnel. Filled detectors: swapped between underground halls via horizontal tunnels. Ling Ao Near 500 m from Ling Ao Overburden: 98 m Ling Ao-ll NPP (under const.) Ling Ao NPP Entrance portal Daya Bay NPP Total tunnel length: ~2700 m Murayama, NNN 2007
3 sensitivity on sin2 213 Murayama, NNN 2007
T2K vs NOA • LBL e appearance • Combination of • sin2213 • Matter effect • CP phase 95%CL resolutionof mass hierarchy Murayama, NNN 2007
Accelerator vs Reactor Reactor w 100t (3 yrs) +T2K T2K (5yr,n-only) Reactor w 10t (3 yrs) +T2K 90% CL 90% CL Reactor experiments can help in Resolving the23 degeneracy (Example: sin2223 = 0.95 ± 0.01) Reactor w 100t (3 yrs) + Nova Nova only (3yr + 3yr) Reactor w 10t (3yrs) + Nova 90% CL McConnel & Shaevitz, hep-ex/0409028 Murayama, NNN 2007
My prejudice 13 12 23 • Let’s not write a complicated theory • The only natural measure for mixing angles is the group-theoretical invariant Haar measure • Kolmogorov–Smirnov test: 64% • sin2 2q13>0.04 (2s) • sin2 2q13>0.01 (99%CL) Murayama, NNN 2007
T2KK CP-violation may be observed in neutrino oscillation! Murayama, NNN 2007
Big Questions Need Synergies
Immediate Questions • Dirac or Majorana? • Absolute mass scale? • How small is q13? • CP Violation? • Mass hierarchy? • Is q23 maximal? Murayama, NNN 2007
What about the Big Questions? • What is the origin of neutrino mass? • Did neutrinos play a role in our existence? • Did neutrinos play a role in forming galaxies? • Did neutrinos play a role in birth of the universe? • Are neutrinos telling us something about unification of matter and/or forces? • Will neutrinos give us more surprises? Big questions tough questions to answer Murayama, NNN 2007
Seesaw Mechanism • Why is neutrino mass so small? • Need right-handed neutrinos to generate neutrino mass , but nR SM neutral To obtain m3~(Dm2atm)1/2, mD~mt, M3~1014–1015 GeV Murayama, NNN 2007
Leptogenesis • You generate Lepton Asymmetry first. (Fukugita, Yanagida) • Generate L from the direct CP violation in right-handed neutrino decay • L gets converted to B via EW anomaly More matter than anti-matter We have survived “The Great Annihilation” • Despite detailed information on neutrino masses, it still works (e.g., Bari, Buchmüller, Plümacher)
Maybe an even bigger role Microscopically small Universe at Big Bang got stretched by an exponential expansion (inflation) Need a spinless field that slowly rolls down the potential oscillates around it minimum decays to produce a thermal bath The superpartner of right-handed neutrino fits the bill When it decays, it produces the lepton asymmetry at the same time (HM, Suzuki, Yanagida, Yokoyama) Neutrino is mother of the Universe? Origin of Universe V() log R Murayama, NNN 2007 t
LHC finds SUSY ILC measures masses precisely If both gaugino and sfermion masses unify, there can’t be new particles < 1014GeVexcept for gauge-singlets LHC/ILC may help Murayama, NNN 2007
0 found LHC discovers SUSY ILC shows unification of gaugino and scalar masses Dark matter concordance between collider, cosmology, direct detection CP in -oscillation found Lepton flavor violation limits (e, e conversion, etc) improve or discovered Tevatron and EDM (e and n) exclude Electroweak Baryogenesis CMB B-mode polarization gives tensor mode r=0.16 Plausible scenario If this happens, we will be led to believe seesaw+leptogenesis (Buckley, HM) Murayama, NNN 2007
Dark Matter • Indirect detection of galactic dark matter • From the Sun, Galactic Center, Subhalos Murayama, NNN 2007
s & s • EGRET down to =210-8cm-2sec-1 • GLAST down to ~10-11cm-2sec-1 • Neutrinos/km3: ~410-10cm-2sec-1 • The catch: • GLAST>GeV • Icecube>100GeV? • Cross-correlation between s & s gives us understanding of the source Buckley, Freese, HM, Spolyar, Sourav Murayama, NNN 2007
Supernova relic neutrinos come from cosmological distances Its spectrum redshifted and superimposed Depends not only supernova rates and spectra, but also on the geometry of space Count Type-II@SNAP In principle, sensitive to Dark Energy HyperGADZOOKS! SCDM CDM 4 Mt years Hall, HM, Papucci, Perez Dark Energy with Neutrinos? Murayama, NNN 2007
Conclusions • Neutrino oscillation a unique tool to probe (very) high-energy world • Era of revolution • sin2 213 decides the future of LBL expts • My prejudice: 13 is “large” • Reactor & accelerator LBL expts complementary • To understand “big questions” we need a diverse set of experiments • Neutrinos are also unique astrophysical probes Murayama, NNN 2007