1. 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

2. 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

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

4. Vacuum alignment& sequential dominance
Red terms dominate

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

6. Effect of small charged lepton mixing angles Antusch, SFK ’05
e.g. Tri-bimaximal ±
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.

7. 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!)

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

9. 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

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

13. 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

14. R.Saakyan: Experimental review of neutrinoless double beta decay
Theory: recent developments in NME calculations e.g. Rodin et al nucl-th/ Mo100 ME to 20%!
Experiment: two approaches to detect electrons: source=detector, or separate calorimeter
Heidelberg-Moscow: <m>= eV (due to
Current experiments: NEMO-3, Cuoricino <m>= eV by 2008
Current NEMO-3: <m>= eV
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> = eV
CUORE (approved) , EXO / SuperNEMO <m>= ev

15. 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

16. 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

17. 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)

18. 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

19. 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

20. 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?