NuHorizons 09: Summary Talk. Amitava Raychaudhuri Harish-Chandra Research Institute Allahabad, India January 2009. Scientist, Visionary, Institution builder. Homi J. Bhabha 1909-1966. Plan. Neutrino Oscillation Mass models High energy neutrinos Supernova neutrinos
Harish-Chandra Research Institute
Homi J. Bhabha
27 May 2008, Neutrino 08
Missed talks by:
Rathin Adhikari, Biswajit Adhikary, Zackaria
Chacko, Sovan Chakraborty. Sandhya
Choubey, Paramita Dey, Pasquale DiBari,
Rikard Enberg, Raj Gandhi, Thomas
Hambye, Mary Hall Reno, Werner
Rodejohann, Sourov Roy, Atsushi
Watanabe, Terribly sorry, folks!
a) Only relative mass splitting
b) Sum of the masses
c) θ12 and θ23
Thanks to S. Choubey
Thanks to S. Choubey
Thanks to A. Paoloni.
Po, Kr the last hurdles
Thanks to R.S. Raghavan
Thanks to R. Raja
atm = 13 - c212 12
normal inverted hierarchy
Usually used 13 -13
Correct only for large θ13
Possible to find hierarchy using atm nu
For small θ13 one must use
two 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
Thanks to K. Dutta
S. Weinberg, Phys. Rev. Lett, 43, 1566 (1979)
There are three tree level realizations: E. Ma, Phys. Rev. Lett, 81, 1171 (1998)
(III) Replacing in (I) by heavy Majorana fermion triplet
Thanks to R. Adhikari
Thanks to B. Dev
→e γ, →eee probe up to 200 TeV.
Thanks to T. Hambye
NMSSM and R-parity violation
Sneutrino vev, LSP decay signals
Testable at LHC!
Thanks to Sourov Roy
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
Parametrised by k,k’, α
Thanks to B. Adhikary
R = 3.2 x 10-2, θ12 = 34o
Thanks to P. Dey
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
Thanks to W. Rodejohann
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
Thanks to P. DiBari
n1 (n4) is the U(1) charge of
(u,d) and (ν,l) doublets.
Anomaly cancellation has to be
If X gauge boson is observed
at LHC , then r may be
determined from its
decay branching fraction
Thanks to R. Adhikari
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
Low energy νN cross sections have significant
At UHE the cross sections are extrapolation
Thanks to M.H. Reno
Low Q extrapolations, from NLO+TMC, with CKMT (and Bodek et al) extrapolation.
NLO + TMC, no special low Q extrapolation.
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
Thanks to R. Gandhi
High energy neutrinos from
heavy quark (c, b) decay:
a) In atmospheric flux
b) From astrophysical sources
Smaller cross section
New, improved QCD calculation
Thanks to R. Enberg
Thanks to A. Watanabe
DSNB 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
Pushep: 11.5N 76.6E
(Near Ooty Hill station)
1km rock coverage
Good tracking and energy
Ease of construction
6cm thick Fe plates
2.5cm gap for RPC trays
2mx2m RPCs interleaved
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