Steve King, Nu-Mass Meeting, Durham Closing remarks G. Ross: Models of Neutrino Mass S. Abel : Pseudo-Dirac neutrinos and leptogenesis S. Palomares-Ruiz: Resolving the LSND Anomaly S.Choubey: Supernova seismology and sterile neutrinos A.Vacheret: The challenges of the T2K 280m near detector S.Cartwright: ANTARES R.Saakyan: Experimental review of double beta decay S.Soldner-Rembold: The COBRA Double Beta Decay Experiment P.Harrison: Leptonic Mixings from a variational principle C.Jarlskog: On quark and lepton masses and mixings 02/11/2019 Steve King, Nu-Mass Meeting, Durham

Unravelling the origin of mass….. 100 10-1 10 10-2 10-3 10-4 eV Unravelling the origin of mass….. G.Ross Many possibilities, many parameters… …difficult (impossible) unless we are lucky! Mixing Small in quark sector, large in lepton sector? Non Abelian Structure? Bi-Tri Maximal Mixing … Harrison, Perkins, Scott ansatz

Vacuum alignment& sequential dominance Red terms dominate SFK ’98-

Vacuum alignment& sequential dominance Red terms dominate

Real vacuum alignment of SO(3) and Pati-Salam SFK hep-ph/0506297 Real vacuum alignment of SO(3) and Pati-Salam

Effect of small charged lepton mixing angles Antusch, SFK ’05 e.g. Tri-bimaximal 35.26± If 13 angles are small have SUM RULE : q12+q13cos(d -p)¼ qn12 q13 and d then come from the charged lepton sector e.g.

d is predicted e.g. tri-bimaximal neutrino mixing plus quark-lepton unification leads to  gives prediction for q12 as function of d Current 3s experimental range Tri-bimaximal value predicts maximal CP violation! (NOT zero CP violation!)

S.Abel Alternatively can get small Yukawa couplings directly from asymmetric compactifications of string theory Antusch, Eyton Williams,SFK

S.Palomares-Ruiz: Resolving the LSND Anomaly With and without sterile neutrinos With one and with more than one sterile With and without neutrino oscillations With and without CPT violation With non-standard and with standard processes With and without extra dimensions With problems and with problems Those we like and those we don’t like Those we have proposed and those we haven’t proposed No solution 3+1 model with a decay option… …but LSND explained by decay SPR, S. Pascoli and T. Schwetz, JHEP0509:048, 2005

A.Vacheret: The Challenges of the T2K 280m near detector

Dark matter search in mSUGRA models S.Cartwright Sun is best “standard” source up to several thousand muons per km2 per year mainly WW and ZZ mainly tt SuSpect + DarkSUSY, Nezri et al

R.Saakyan: Experimental review of neutrinoless double beta decay Theory: recent developments in NME calculations e.g. Rodin et al nucl-th/0503063 Mo100 ME to 20%! Experiment: two approaches to detect electrons: source=detector, or separate calorimeter Heidelberg-Moscow: <m>=0.1-0.9eV (due to NME) @2.5\sigma Current experiments: NEMO-3, Cuoricino <m>=0.2-0.6eV by 2008 Current NEMO-3: <m>=0.3-2.8eV Future experiments:incl. UK expts. SuperNEMO, COBRA GERDA (approved) Ge-76 phase I confirm/rule out Klapdor in 3-years GERDA phase III (possible merger with Majorana) <m> =.03-.09eV CUORE (approved) 0.03-0.1, EXO / SuperNEMO <m>=0.04-0.08ev

S.Soldner-Rembold: SuperNEMO (UK R&D) SuperNEMO = extrapolation of NEMO-3 by an order of magnitude Mo100Se82 (PPARC R&D approved 05) Challenges: energy resolution (thin wires), choice of isotope, background (photone+e-) Sites: Boulby mine (low background from potash), Gran Sasso… Can see event by event B. Morgan: COBRA (UK R&D) COBRA Cadmium –Tellurium 0-neutrino Beta decay Research Apparatus Semiconductor source=detector, CZT crystals, clean, good energy resolution Test facilities in Gran Sasso to study background 64-array under construction

P.Harrison: Lepton mixings from a variational principle Dirac masses Jarlskog covariance – MNS is invariant under a change of basis Write everything in terms of basis invariants e.g. CP violating observable J NuSM : attempt to explain lepton mixing by extremising a flavour-symmetric Jarlskog invariant Promote Yukawa couplings to dynamical variables Not yet a theory

C.Jarlskog: on quark and lepton masses and mixings Invariants of mass matrices are the only reliables Texture zeros, Input: texture zeroes, Output: predictions An important discovery should be expressible in an invariant form A new parametrisation of a unitary matrix – generalisable to nxn, convenient if there is a hierarchy There may be a preferred basis if there is a broken family symmetry– determined by vacuum alignment (the most convenient basis to work in)

LBL  Reactor Nufact/beta/super Experimental Summary Seven experimental challenges for neutrino physics: #1. Count the number of neutrinos #2. Measure the neutrino mass scale #3. Determine the sign of the mass ordering #4. Measure the deviation of q23 from maximal #5. Measure q13 #6. Measure d #7. Measure the deviation of q12 from tri-bimaximal mixing MiniBooNE - soon (b b)0n and KATRIN Nufact/beta/super Hyper-K LBL  Reactor Nufact/beta/super Nufact/beta/super

Theory Summary TOE (M-theory) GUT+Flavour theory See-saw model Leptogenesis No direct link (need to go via see-saw model) RGE Muon flavour violation Neutrino masses and mixings

Future of UK Neutrino Network Next meeting – in April at RAL after ISS meeting? Grant expires in Spring 06 – should we continue? Jointly with experimentalists?