1 Summary of the session: Interplay between neutrino masses and other phenomenological signatures Tommy Ohlsson Department of Theoretical Physics, Royal Institute of Technology (KTH), Stockholm, Sweden NuFlavor 2009, Abingdon, UK June 10, 2009

2 Schedule of session 14:00-14:30 Neutrinos at the LHC (T. Schwetz) 14:30-15:00 Phenomenological perspective on LFV processes (A. de Gouvêa) 15:00-15:30 NSI (E. Fernández-Martínez) 15:30-16:30 Discussion (T. Ohlsson)

3 Collider physics (Tevatron and LHC) and electroweak precision data LFV decays LHC signatures: pp  ℓ ± ℓ ± ℓ -/+ + jets pp  ℓ ± ℓ -/+ + jets Seesaw models (e.g. a Higgs triplet model) Seesaw models lead to neutrino masses. TeV scale neutrino mass models: Doubly charged scalars at the LHC: pp  H ++ H --  ℓ + ℓ + ℓ - ℓ - (Cf. Thomas Schwetz’ talk) Tests of neutrino mass models Bounds on NSIs Bounds on NSIs (Davidson et al., 2003) Loop bounds on NSIs (Blennow et al., 2009)

4 Lepton flavor violating decays LFV decays (Cf. André de Gouvêa’s talk) ℓ   ℓ  +  such as   e +  and    +    3e and   3ℓ The most stringent experimental bounds come from   3e and   3ℓ The LHC inverse problem: If one observes LFV processes at LHC, then can one determine the mechanism behind neutrino mass generation. (Cf. Thomas Schwetz’ talk)

5 Neutrino physics parameters What observables should we measure? (Cf. round-table discussion with Ken Long) -Phases (i.e., neutrino mass-squared differences) -Amplitudes (i.e., elements of the leptonic mixing matrix) Parameters to search for in the future: θ 13 Sign of Δm 31 2 (normal or inverted hierarchy) δ (Dirac CP-violating phase) Majorana CP-violating phases NSI and non-unitarity mixing parameters? Better precision for already known parameters: θ 12, θ 23, Δm 21 2,|Δm 31 2 | Is tri-bimaximal mixing the solution?

6 Constraints on NSI parameters Adopted from Malinský et al.,

7 Most interesting physics scenarios In the combination of different information, what are the most interesting physics scenarios from the phenomenological (=parameter) and theoretical (=model) point of view? Which models are best motivated? NSIs Non-unitarity mixing CPT and non-locality violation Other exotic models What is the relation between NSIs and non- unitarity mixing? (Cf. Enrique Fernández-Martínez’ talk) NSIs from MSSM? (Cf. Enrique Fernández-Martínez’ talk)

8 When can we expect interesting connections? Bounds from astrophysics on: The sum of neutrino masses The number of neutrinos (Cf. Steen Hannestad’s talk)

9 How to search for new physics in neutrino experiments? Hard to test typical seesaw models for neutrino masses at LHC, but like-signed lepton events may be the most promising signatures. Try to find the best experimental setups to probe e.g. NSIs. (Cf. Enrique Fernández-Martínez’ talk) Look at different baselines, channels, and facilities. Possible setups: neutrino factory, -beams, super-beams etc.