content standard model does not permit lfv most common introduction of neutrino masses

Lepton flavour violation (tau decays) A.Ilakovac, Dept. of Physics, Faculty of Science, U. of Zagreb, Croatia ENT dard model does not permit LFV common introduction of neutrino masses ces of LFV/LNV l-independent (operator) analysis of LFV with SM fi mechanisms ecting LFV with neutrino parameters ples of interrelations between processes onic part of LFV amplitudes results for tau-lepton processes lusions

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Lepton flavour violation (tau decays) A.Ilakovac, Dept. of Physics, Faculty of Science, U. of Zagreb, Croatia. CONTENT Standard model does not permit LFV Most common introduction of neutrino masses Sources of LFV/LNV Model-independent (operator) analysis of LFV with SM fields LFV mechanisms - PowerPoint PPT Presentation

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Page 1: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

Lepton flavour violation (tau decays)

A.Ilakovac, Dept. of Physics, Faculty of Science,

U. of Zagreb, Croatia

CONTENTStandard model does not permit LFVMost common introduction of neutrino massesSources of LFV/LNVModel-independent (operator) analysis of LFV with SM fieldsLFV mechanismsConnecting LFV with neutrino parametersExamples of interrelations between processesHadronic part of LFV amplitudesSome results for tau-lepton processesConclusions

Page 2: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 3: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 4: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 5: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 6: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 7: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 8: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 9: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 10: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 11: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

Two approaches to determine see-saw parameters:

1. top-down: start with a specific model (GUT, Froggatt-Nielsen, strings,…) and compare the predictions with the experiments, [many different possibilities]

2. bottom-up: exploit all the information available at low energies on the leptonic sector in order to resconstruct the high-energy theory; completely phenomenological, [very difficult in practice]

[A. Ibarra: impossible in SMv ; possible in MSSM]

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 12: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 13: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 14: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

2. LFV and LFC

Page 15: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

Hadronic part of LFV amplitudes

-tau-lepton is heavy enough to decay into hadrons – LFV with hadrons in the final state possible

- simplest hadronization methods: (a) PCAC –axial vector (b) VMD –vector (c) chiral perturbation theory – scalar and pseudoscalar (e.o.m. for current quark masses gives similar results) (d) tensor: e.o.m. for current quark masses and (b)

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 16: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 17: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

M.J. Herrero, hep-ph/0510405

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 18: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

P. Paradisi, Flavour in the era of the LHC, CERN, February 2006

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006

Page 19: CONTENT Standard model does not permit LFV Most common introduction of neutrino masses

CONCLUSIONS

1.Lepton flavour violation must occur at some level.

2. Discovery of any of LFV processes, except neutrino oscillations would give important information on the structure of theory.

3. LFV processes have to be always analyzed taking into account information of all other LFV and LFC processes.

4.Many theoretical models are not completely explored, and in specific regions of parameter space give results comparable to the present experimental limits for BRs of neutrinoless LFV processes. For some SUSY models large regions of parameter space are excluded by LFV experimental data. In this context tau-lepton LFV data play important role.

A. Ilakovac, U. of Zagreb, Novosibirsk, February 2006