NuHorizons 09: Summary Talk Amitava Raychaudhuri Harish-Chandra Research Institute Allahabad, India January 2009

NuHorizons 09: Summary Talk

Amitava RaychaudhuriHarish-Chandra Research Institute

Allahabad, India

January 2009

Summary TalkA. Raychaudhuri

January 09, 2009 NuHoRIzons 09 2

Homi J. Bhabha

1909-1966

Scientist,

Visionary,

Institution

builder



27 May 2008, Neutrino 08

Plan

• Neutrino Oscillation • Mass models• High energy neutrinos• Supernova neutrinos• Dark matter• INO



Highlight!

Fog!

Flight

Cancellations

Train

delays



ApologiesMissed talks by:Rathin Adhikari, Biswajit Adhikary, Zackaria Chacko, Sovan Chakraborty. SandhyaChoubey, Paramita Dey, Pasquale DiBari,Rikard Enberg, Raj Gandhi, Thomas Hambye, Mary Hall Reno, Werner Rodejohann, Sourov Roy, Atsushi Watanabe, Terribly sorry, folks!





Neutrino parameters

• Three masses m1, m2, and m3

• Three mixing angles: θ12, θ23, and θ13

• CP phases δ, α, β• Known at the moment

a) Only relative mass splitting

b) Sum of the masses

c) θ12 and θ23

oscillation experiments ν-mass 0νββ cosmology/astrophysics



Status: Δm212 and θ12

Thanks to S. Choubey



Status: Δm231 and θ23

Thanks to S. Choubey



OPERA• OPERA: CERN to LNGS νντ through τ detection• Emulsion Cloud Chamber technique• Emulsion + electronic detection• First results

Thanks to A. Paoloni.



Borexino• 100 Tons• Purity is critical:

Po, Kr the last hurdles• Environmental issue: delay• 192-day results consistent with

MSW LMA• Get Be flux to 5%

Thanks to R.S. Raghavan



MIPP

• Main Injector Particle Production experiment

• Test Non-perturbative QCD, scaling laws, shower simulation, etc.

• Relevant for MiniBoone, atmos. nu, nu factories

• Data (05-06) analysis on

Thanks to R. Raja



If 13 is vanishingly small….

atm = 13 - c212 12

normal inverted hierarchyUsually used 13 -13

Correct only for large θ13 Possible to find hierarchy using

atm nu

For small θ13 one must usetwo different expts

Advantage of Long baseline expt

Thanks to P. Ghoshal



Neutrino mass changes with epoch

Acceleron field contribution to mν besides type I see-saw

As neutrino density decreases 2nd term begins to dominate

Effect mimics dark energy with

weff < -1

Not ghosts or vac instability

Rather support for MAVAN

Mass varying neutrinos

Thanks to K. Dutta


January 09, 2009 NuHoRIzons 09 15 15

Effective operator for neutrino mass

There are three tree level realizations: E. Ma, Phys. Rev. Lett, 81, 1171 (1998)

(I) (II)

(III) Replacing in (I) by heavy Majorana fermion triplet

S. Weinberg, Phys. Rev. Lett, 43, 1566 (1979)

Thanks to R. Adhikari



Post-sphaleron baryogenesis

• PS224 Quark-lepton symmetry Δ(1,3,10) Δνν ≡ S

• S develops a vev: 10-100TeV• Baryogenesis from S-decay, neutron-antineutron oscillations• Neutrino masses through Type-II see-saw

Thanks to B. Dev



Phenomenology of Type III see-saw

• Triplets under SU(2), Σ couples to gauge bosons. LHC production up to 1.5 TeV.

• Σ+c can mix with charged

lepton. Rare decays, e.g.,

→e γ, →eee probe up to 200 TeV.

• Decay branching ratios are

important

• L-violation, leptogenesisThanks to T. Hambye



TeV-scale see-saw

Thanks to Sourov Roy

NMSSM and R-parity violation

Sneutrino vev, LSP decay signals

Testable at LHC!



See-saw models with a Z’Models with a Z’ under which RH neutrinos (TeV-scale) are charged.

TeV scale Z’, when produced, will decay to NRNR which decay to charged leptons (could be same sign)

TeV scale Majorana NR carry additional lepton number violation -- flavour dependent -- and erase baryon asymmetry created earlier.

Prevention of washout yields an UPPER bound on NR mass. e.g., Type I: 300 GeV for degenerate case and 1 TeV for IH. No bound for NH. Similar (but tighter) constraints for Type III

Testable at the LHC

Thanks to. Z. Chacko



Four-zero textures and symmetry

• 126 four-zero texture mass matrices possible

• Two compatible with symmetry

• Predictive: θ23 = π/4, θ13 =0 Parametrised by k,k’, α

Thanks to B. Adhikary

R = 3.2 x 10-2, θ12 = 34o



Triplet Higgs, S3 symmetry, Lepton masses

• Also add discrete Z3 or Z4 symmetry• 2 Higgs triplets: Type II see-saw for nu mass• Mild breaking of τ symmetry: small θ13

• LHC charged higgs signals? Thanks to M. Mitra



Two-loop neutrino masses in SUSY

• Neutrino masses from R-parity violating SUSY and sqauark non-degeneracy. Large couplings may contradict ν-mass.

• Sets of couplings may be chosen so that 1-loop vanishes.• Two loops do the job (one diagram shown)

Thanks to P. Dey



RG evolution for Type III see-saw

Type III see-saw relies on SU(2) triplet fermions

They contribute to gauge coupling evolution as well as to Yukawa and Higgs self couplings affecting neutrino mass and mixing evolution.

Calculation in Rξ gauge ensures gauge invariance

Running of MΣ Is significant.

Threshold effects and Majorana phases are important

CP phase δ undefined at θ13 = 0. Careful handling using Jarlskog J shows there is no singularity.

Thanks to. S. Ray



Deviations from tri-bimaximal mixing

• Deviations from TBM• Different options• Other patterns?

Thanks to W. Rodejohann

θ13 ≠0?



Stable right-handed neutrino could be warm dark matter

See-saw prefers heavier νR unless Dirac mass is chosen small

Consider three RH neutrinos of which one is heavy and the others light. Lightest (TeV scale or more) is long lived and a dark matter candidate.

Abundance is a difficulty

Can abundance be enhanced through oscillations from the other light state?

Yes, through dimension-5 operators

Dark matter from νR mixing

Thanks to P. DiBari



n1 (n4) is the U(1) charge of (u,d) and (ν,l) doublets.

Anomaly cancellation has to be respected

If X gauge boson is observed at LHC , then r may be determined from its decay branching fraction

Thanks to R. Adhikari

Models with extra U(1) symmetry



Rare lepton decays are interesting Quark sector is suggestive

Experiments (e.g, BaBar and Belle) are pushing the boundary

Constrain MSSM (slepton mixing)? Neutrino masses (See-saw + MSSM)?

Thanks to A. Ibarra

Rare τ decays



Neutrino cross sections

Low energy νN cross sections have significant uncertainty(next slide)

At UHE the cross sections are extrapolation based.

Detailed exposition

Thanks to M.H. Reno



LO+TMC

Low Q extrapolations, from NLO+TMC, with CKMT (and Bodek et al) extrapolation.

NLO + TMC, no special low Q extrapolation.

MHR, Phys. Rev. D74 (2006)



New era in high energy neutrino astronomy

Neutrino fluxes better estimated through TeV gamma measurements and UHE cosmic ray information

UHE neutrinos probe BSM physics: Extra dimensions, black holes, …

Neutrino flavour ratios carry important clues

Radio detection beyond GSM is a possibility worth exploring

High Energy ν

Thanks to R. Gandhi



Prompt neutrinos

High energy neutrinos from

heavy quark (c, b) decay:

a) In atmospheric flux

b) From astrophysical sources

Smaller cross section

Harder spectrum

New, improved QCD calculation

Thanks to R. Enberg



Prompt neutrino from charm decay from supernova

Slow jets: Like GRB but lower Lorentz boost

Resulting diffuse background is small, but individual point sources possible

Boosted from comoving frame to earth frame

TeV energy neutrinos

May be detectable in km3 detectors

Thanks to A. Watanabe

Charm decay ν from supernova



Diffuse supernova nu backgroundDSNB from supernova explosions in the past.

Depends on supernova rate. SN neutrino spectrum required.

Collective effects – ν-ν interaction driven – are important.

Complete swapping for IH, No effect for normal hierarchy.

MSW also has to be included farther out

Thanks to S. Chakraborty



INO site

Pushep: 11.5N 76.6E

(Near Ooty Hill station)

Masinagudi 6.5km

Mysore 96.5km

Bangalore 350km

1km rock coverage



Schematic of 50 kton ICAL

Large Mass

Good tracking and energy

resolution

Good directionality

Charge ID

Ease of construction

6cm thick Fe plates

2.5cm gap for RPC trays

2mx2m RPCs interleaved



Development of large area glass RPCs

Thanks to N.K. Mondal



Absolute neutrino mass measurement from 0ν2β expts ~ 0.03 eV

Determine sign of Δm231. CP-phase δ

Pin down θ13. Hints of non-zero value?

Sterile neutrinos? Why light, even if they are there?

Km3 detectors for UHE neutrinos

Much activity in mass models, tribimaximal, testability

Supernova neutrinos, Leptogenesis, …

Looking forward to NuHoRIzons 2010

Looking ahead





Thank you

Documents

NuHorizons 09: Summary Talk Amitava Raychaudhuri Harish-Chandra Research Institute Allahabad, India January 2009