Neutrino Mass and Flavor Physics R N Mohapatra

Neutrino Mass and Flavor Physics R. N. Mohapatra

Neutrino Mass- What do we know ? n Masses: ; Mixings: ; Overall mass scale: <. 1 - 1 e. V (roughly) n To be determined (expts in progress or planning) n n (i) Majorana or Dirac ? (ii) Mass ordering: NH or IH (iii) Value of (iv) Any possible CP violation ? (v) Leptonic unitarity

Many experiments on the way (i) Majorana or Dirac (ii) Absolute mass scale: (iii) Mass ordering: (iv) Value of (v) CP phase

Plan of the talk n Neutrino mass New physics beyond SM: n Raises two new issues: n New mass scale to explain why Is it accessible at the LHC ? n New approach to flavor : Can we have a unified understanding quark- lepton mixings ?

Why n n ? Seesaw Paradigm: Add heavy right handed neutrinos play seesaw: to SM and Seesaw scale is the new physics scale !! Two different seesaws depending on whether N Majorana or Dirac

Type I seesaw n n n Majorana Breaks B-L : New scale and new symmetry beyond SM. After EWSB -Neutrino majorana key parameter to test seesaw n. Minkowski, Gell-Mann, Ramond Slansky, Yanagida, Mohapatra, Senjanovic, Glashow type I

Inverse Seesaw n Mostly Dirac n Seesaw parameter testing i. e. add another singlet or larger (RNM’ 86; RNM, Valle’ 86)

New physics signal for simplest seesaw n Strength given by n e. g. collider production: n n n or mixing: Leptonic non-unitarity: Both negligible for type I seesaw but observable for inverse seesaw MN ~ Te. V Situation different with gauge forces !!

1. Seesaw (B-L) scale n n Neutrino masses do not determine seesaw scale ; MU ~ Ge. V Both and high seesaw scale indication for SUSYGUTs; No collider signals ! (Common Lore) n B-L scale at Te. V LHC signalsseesaw with only gauge forces; No GUTs with type I. Inverse n B-L at Te. V and GUTs can co-exist: since possible (Dev, RNM’ 09)

A concrete realization: Low scale B-L in Left-Right n NR Gauge group: n New W’ and Z’ n n Fermion assignment Two Avatars of LR: type I Inverse seesaw +

Bound on SUSYLR scale from Low energy data n n M_WR > 2 Te. V from a combination of KL-KS, epsilon, d_n together. (uncertainty from long distance contribution); (An, Ji, Zhang’ 07)

Bounds from Nu-less double beta decay n n New contributions from WR-N exchange (only for Case I) (RNM, 86; Hirsch, Klapdor, Panella 96) Diagram: From Ge 76:

Seesaw signal from n Nu contribution: Inverse hierarchy Normal hierarchy Punch line: n Suppose long baseline n and nonzero signal for (+ RP if susy ) Te. V WR and type I

Constraints on Seesaw scale from coupling unification: n Te. V type I does not grand unify: Landau Pole n n (Kopp, Lindner, Niro, Underwood’ 09) (Parida, Sarkar, Majee, Raichaudhuri’ 09) n Discovery of type I signal at LHC will rule out GUTs.

Te. V Inverse Seesaw (LR) n Inverse seesaw n Look for not only susy but also WR, Z’, N at LHC: (Dev, RNM, does unify and give realstic model: with both WR and Z’ in Te. V range; MSSM GUT SUSYLR GUT 09; PRD);

SO(10) as the GUT theory n {16 }- spinor for all matter n Type I: only unification route: n Inverse seesaw:

Radiative Breaking of B-L and SM n n n Positive spartner mass square at GUT scale. RGE turns them negaitve much like SM with large t-mass (Dev, RNM’ 10)

LHC Signals for seesaw n n LHC production of WR: N-decay: type I Inv. Seesaw: Type I case: (Keung, Senjanovic; Han, Perez, Huang, Li, Wang; Del Aguila, Aguilar-Saavedra; Azuelos, . . ) n Inverse seesaw: Only Trileptons; no same sign dileptons(30 fb^-1) (del Aguila, Aguilar-Saavedra, de Blas) ;

Other Te. V scale Type I Signals n n n Te. V type I Seesaw requires B-L=2 Higgs: Doubly charged Higgs can have sub-Te. V mass. Decays to lepton pairs LHC signals for type I seesaw will rule out simple GUTs n Four lepton signals at LHC

New Dark matter in Te. V scale Inverse seesaw: n n If super-partner of RH neutrino is the lightest, it will be stable due to R-parity- become DM. Soft breaking: Minimal Type I case: Usual Bino. Lightest linear combination is dark matter: Higgsino n n

Dark matter in type I GUT vs Te. V scale Inverse seesaw: n Inverse seesaw case: (Fornengo, Arina, Bazzochi, Romao, Valle’ 08) New DM : : Two contributions to relic density: Z’ exchange (Matchev, Lee, Nasri) No or small Z’ effect

2. Understanding Flavor (i) Mass hierarchies (ii) Strange mixing patterns: Leptons: Quarks: UPMNS= UCKM = (Harrison, Perkins, Scott; He, Zee, Wolfenstein; Xing, . . )

Mass Texture n Up-quark and charged lepton diagonal basis: n n = Cabibbo angle

Strategy for texture n Key idea: SM has a large sym for zero fermion masses : [SU(3)]^5; n Choose subgroup: Discrete subgroup with 3 -d. rep. n Replace Yukawa’s by scalar fields (flavons); n Minima of the flavon theory determines Yukawas:

Application to Neutrinos n Successful Family symmetries for TBM: Flavon fields are triplets: (Ma, Rajasekaran; Babu, Ma, Valle, King, Ross; Altarelli, Feruglio, Chen, Mahanthappa; Everett, Ramond; Luhn, Nasri, Yu, RNM, Hagedorn, Morissi, …. . ) How can we unify with quarks ? Grand unified theories: SU(5)

High scale Ansatz for unifying quark-lepton flavor A n (Dutta, Mimura, RNM’PRD-09) f diagonal. Anarchic M 0, quark mixings small while lepton mixings large. Rank 1 M 0 B explains mass hierarchies + n

SUSY SO(10) realization n Fermions in {16}: n 16 mx 16 m={10}H+{126}H n Fermion masses from Yukawas as in SM: ( Babu, Mohapatra, 93)

Neutrino mass formula in GUT scale B-L in SO(10): Lazaridis, Shafi, Wetterich; R. N. M. , Senjanovic’ 81 n Type II seesaw:

SO(10) with GUT scale B-L unified approach to flavor n fermion mass formulae: n (Babu, Mohapatra’ 92) n n Bajc, Senjanovic, Vissani’ 03 For f, h’ << h, yields ansatz part A at MU; Rank from flavor symmetry: e. g.

An S 4 x. SO(10)- example n Solar mass n Bottom-tau: n Leading order PMNS: U Dutta, Mimura, RNM ar. Xiv: 0911. 2242 and (Harrison, Perkins, Scott; He, Zee, Xing; Wolfenstein) n Corrections: Testable Bjorken, King, Pakvasa Ferrandis; Chen, Mahanthappa n Double beta mass 3 me. V.

Prospects for measuring n Reactor, Long base line e. g. T 2 K, No. VA: (Lindner, Huber, Schwetz, Winter’ 09) Our prediction

Conclusion: n Te. V scale WR compatible with SO(10) GUT; Can be tested at LHC; New dark matter candidate: n New unified approach to flavor based on type. II+ SO(10)- testable via theta_13.

WR, Z’ at LHC_14 n n Production : WR Z’

Signals for Type I case n Two and three lepton signals in colliders n N-decay gives signal: n Like sign dilepton plus trilepton+ n (Han, Perez, Li, Del Aguila, Aguilar Saavedra, …)

Inverse seesaw case n N is mostly Dirac n Collider leptonic signal from WR production: n No like sign dilepton but only trileptons +

Distinguishing between seesaws n Observation of relative abundance of like sign dileptons vs trileptons can distinguish between Te. V scale Inverse seesaw vs type I seesaw n (Aguilar-Saavedra) n Type I n Inverse