neutrino physics hitoshi murayama (berkeley+ipmu) nnn 2007, hamamatsu oct 3, 2007

Neutrino Physics

Hitoshi Murayama (Berkeley+IPMU)

NNN 2007, Hamamatsu

Oct 3, 2007

Murayama, NNN 2007 2

Outline

• Past: Why Neutrinos?

• Present: Era of Revolution

• Near Future: Bright Prospect

• Big Questions: Need Synergies

• Astrophysical Probe

• Conclusion

Past

Why Neutrinos?


Probe to High Energies

• Effects of physics beyond the SM as effective operators

• Can be classified systematically (Weinberg)


Unique Role of Neutrino Mass

• Lowest order effect of physics at short distances

• Tiny effect (m/E)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


Ubiquitous Neutrinos

They must have played some important role in the universe!


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?

Present

Era of Revolution


The Data

Evidence for oscillation:• “Indisputable”

– Atmospheric– Solar– Reactor

• “strong”– Accelerator (K2K)

And we shouldn’t forget:• “unconfirmed”

– Accelerator (LSND)

excluded?


SuperKamiokande Atmospheric disappear

Downwards ’s don’t disappear

1/2 of upwards ’s do disappear

2/dof=839.7/755 (18%)

m2=2.510-3 eV2

sin22=1


SNOSolar transform in flavor

2/3 of e’s


KamLANDReactor neutrinos do oscillate!

Proper time L0=180 km

TAUP 2007, preliminary


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


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


Immediate Questions

• Dirac or Majorana? • Absolute mass scale?

• How small is 13?

• CP Violation?• Mass hierarchy?

• Is 23 maximal?

Future

Bright Prospect


Immediate Questions




• Is 23 maximal?


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


Immediate Questions




• Is 23 maximal?


T2K (Tokai to Kamioka)


Immediate Questions




• Is 23 maximal?

• LSND? Sterile neutrino(s)? CPT violation?


LMA confirmed by KamLAND

• Dream case for neutrino oscillation physics!

• m2solar within reach of long-baseline expts

• Even CP violation may be probable

• Possible only if:– m12

2, s12 large enough (LMA)

– 13 large enough€

P(ν μ → ν e ) − P(ν μ → ν e ) = −16s12c12s13c132 s23c23

sinδ sinΔm12

2

4EL

⎛

⎝ ⎜

⎞

⎠ ⎟sin

Δm132

4EL

⎛

⎝ ⎜

⎞

⎠ ⎟sin

Δm232

4EL

⎛

⎝ ⎜

⎞

⎠ ⎟


13 decides the future

• The value of 13 crucial for the future of neutrino oscillation physics

• Determines the required facility/parameters/baseline/energy– sin2213>0.01 conventional neutrino beam– sin2213<0.01 storage ring, beam

• Two paths to determine 13

– Long-baseline accelerator: T2K, NOA– Reactor neutrino experiment: 2CHOOZ, Daya Bay


NOAFermilab to Minnesota

32-planeblock

Admirer

25ktMINOSNOA

L=810km


Daya BayNPP

Ling AoNPP

Ling Ao-ll NPP(under const.)

Empty detectors: moved to underground halls through access tunnel.Filled detectors: swapped between underground halls via horizontal tunnels.

Total tunnel length: ~2700 m

230 m290 m 7

30

m

570 m

910 m

Daya Bay Near360 m from Daya BayOverburden: 97 m

Ling Ao Near500 m from Ling AoOverburden: 98 m

Far site1600 m from Ling Ao2000 m from DayaOverburden: 350 m

Mid site~1000 m from DayaOverburden: 208 m

Entrance portal

Daya Bay


3 sensitivity on sin2 213


T2K vs NOA

• LBL e appearance

• Combination of– sin2213

– Matter effect

– CP phase 95%CL resolutionof mass hierarchy


Accelerator vs Reactor

90% CL

Reactor w 100t (3 yrs) + Nova Nova only (3yr + 3yr) Reactor w 10t (3yrs) + Nova

90% CL

McConnel & Shaevitz, hep-ex/0409028

90% CL

Reactor w 100t (3 yrs) +T2K T2K (5yr,-only) Reactor w 10t (3 yrs)+T2K Reactor experiments can help

in Resolving the 23 degeneracy

(Example: sin2223 = 0.95 ± 0.01)


My prejudice

• 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 213>0.04 (2)

• sin2 213>0.01 (99%CL)

231213


T2KKCP-violation may be observed

in neutrino oscillation!

Big Questions

Need Synergies


Immediate Questions




• Is 23 maximal?


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


Seesaw Mechanism

• Why is neutrino mass so small?

• Need right-handed neutrinos to generate neutrino mass

νL νR( )mD

mD

⎛

⎝ ⎜

⎞

⎠ ⎟ νLνR

⎛

⎝ ⎜

⎞

⎠ ⎟ νL νR( )

mD

mD M

⎛

⎝ ⎜

⎞

⎠ ⎟ νLνR

⎛

⎝ ⎜

⎞

⎠ ⎟ mν =

mD2

M<<mD

To obtain m3~(m2atm)1/2, mD~mt, M3~1014–1015 GeV

, but R SM neutral

35

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)

Γ(N1→ νiH)−Γ(N1 → νiH)∝ Im(h1jh1khlk*hlj

*)


QuickTime™ and aCinepak decompressor

are needed to see this picture.

QuickTime™ and aCinepak decompressor

are needed to see this picture.

Origin of Universe

• 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?

V()

t

log

R


LHC/ILC may help

• LHC finds SUSY

• ILC measures masses precisely

• If both gaugino and sfermion masses unify, there can’t be new particles < 1014GeV except for gauge-singlets


Plausible scenario

• 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

If this happens, we will be led to believeseesaw+leptogenesis (Buckley, HM)

Neutrinos as Astrophysical Probe


Dark Matter

• Indirect detection of galactic dark matter

• From the Sun, Galactic Center, Subhalos


s & s

• EGRET down to =210-8cm-2sec-1

• GLAST down to ~10-11cm-2sec-1

• Neutrinos/km3: ~410-10cm-2s ec-1

• The catch: – GLAST>GeV– Icecube>100GeV?

• Cross-correlation between s & s gives us understanding of the source

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Ç™Ç±ÇÃÉsÉNÉ`ÉÉÇ å©ÇÈÇΩÇflÇ…ÇÕïKóvÇ≈Ç∑ÅB

Buckley, Freese, HM, Spolyar, Sourav


Dark Energy with Neutrinos?

• 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!

Hall, HM, Papucci, Perez

4 Mt years

CDM SCDM


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

neutrino physics hitoshi murayama (berkeley+ipmu) nnn 2007, hamamatsu oct 3, 2007

Documents

nnn 2007t2k tokai

pastwhy neutrinos

mass hierarchy

kamlandreactor neutrinos

origin of neutrino mass

absolute mass scale

tiny mass

neutrino oscillation