Probing TeV Scale Left-Right Seesaw

Transcription

1 Probing TeV Scale Left-Right Seesaw R. N. Mohapatra Scalars 2013, Warsaw

2 BSM Particle physics landscape LR, SO(10),. m ν Axions, Left-right Strong CP Baryogenesis SM D M Gauge hierarchy Inflation,DE Susy Extra Dim SUSY,Extra D,axions,mirror world,..

3 BSM Particle physics landscape This talk LR, SO(10),. m ν Axions, Left-right Strong CP Baryogenesis SM D M Gauge hierarchy Inflation,DE Susy Extra Dim SUSY,Extra D,axions,mirror world,..

4 Where does neutrino mass come from? n For charged fermions, mass comes from the Higgs vev m f = h f v wk v wk =<h 0 > Discovery of the 125 GeV Higgs h 0 confirms this. n For neutrinos, this formula gives too large a mass- requires h ν 10 12!! n There is a second mass problem!!

5 Weinberg Effective operator as a clue n Weinberg effective operator: λ LHLH M à m ν = λ v2 wk M λ 1; M n big à m ν naturally! m f n What is the Physics of M? n To explore this, seek UV completion of Weinberg operatorà seesawà M-physics

6 Type I SEESAW n UV completion by adding SM singlet heavy Majorana neutrinos N to SM à m ν 2 hν v M wk R 2 m D = hv wk (Minkowski 77; Gell-Mann, Ramond, Slansky; Yanagida;Glashow; Mohapatra,Senjanovic 79)

7 Questions raised by seesaw n Where did N come from? n Where did the seesaw scale come from? n Two theories that provide answers to these questions very economically are: (i) Left-right model where N is the parity partner ν of and seesaw scale is SU(2) R scale!! (ii) SO(10) GUT where N+15 SM fermions =16 spinor and seesaw scale = GUT scale.

8 Seesaw scale and testing seesaw experimentally (ii) GUT embedding e.g. SO(10)à very natural since h ν h q due to q-l unif. but since, M R ~10 14 GeV: very hard to test!! (ii) Left-right can have M R TeV scale: many tests! However, even here, Generic theoryà h ν Leaves out a lot of seesaw parameter space e.g. theories with larger h ν allow access to it! Are there such theories? would

9 Testing TeV seesaw n Neutrino Matrix: M ν = m D = h ν v wk ν N 0 md m T D M N n Two ways: (i) Majorana mass M N (breaks L): (ii) ν N mixing: V N = h νv wk M N

10 Two points of the talk: n Are there natural models which have yet have both tiny m ν.1 ev so that V N is large i.e. Allows excess to a larger part of seesaw parameter space! h ν.01 n What are the tell-tale experimental signatures of such a scenario?

11 A Strategy for large V N m D = with TeV M N m 1 δ 1 1 m 2 δ 2 2 m 3 δ 3 3 (Kersten, Smirnov 07) n Note if à (sym lim.) i m i n sym. Br. ; M N = m ν m im j M 2 n Seesaw à << m e,q M 2 1 n For m i,j ~1-10 GeV, M 1,3 > 100 GeV,à < (other ex.: Pilaftsis,Underwood 05; Soni, Kiers.. 06; Haba, Mimura.. 11; He et al 09; Mitra et al. 11) i, δ i,m 2 =0 m νi =0 δ i, M 2 M 1,3 + i j 0 M 1 0 M 1 M M 3 M 1 V N

12 Left-Right Model embedding n LR basics: Gauge group: n Fermions n Parity a spontaneously broken symmetry: L B R L U SU SU ) (1 (2) (2) L L d u R R d u L L e ν R R e ν P P ] [ 2 R R L L W J W J g L µ µ µ µ + = M WR M WL

13 Scalar sector and seesaw n SU(2) R x U(1) B-L à U(1) Y by (Mohapatra and Senjanovic; Minkowski) R Vev: à n SM Higgs is in: n Leads to seesaw matrix: Δ Δ Δ Δ Δ = < Δ >= v R M N = fv R = φ φ φ φ φ = ' 0 0 κ κ φ

14 Parity breaking and neutrino mass n Seesaw formula from parity breaking: 0 hκ n M ν,n = hκ fv R à m ν (hκ)2 fv R M WR = gv R n Generic version (I) needs small M n WR V N 2.9TeV h (CMS, ATLAS) and

15 Realistic LR embedding of enhanced V N (II) n New model based on SU(2) L xsu(2) R xu(1) B-L x(z 4 ) 3 f 12 R 1 R 2 R,1 + f 33 R 3 R 3 R,2 + h.c. 0 0 n Sym lim. < φ a >= 0 κ a ; M = M D = L Y = h α1 Lα φ1 R 1 + h α2 Lα φ 3 R 2 + h α3 Lα φ 2 R h 12 κ 3 h 13 κ 2 0 h 22 κ 3 h 23 κ 2 0 h 32 κ 3 h 33 κ 2 h 11 κ h 21 κ h 31 κ M R = à m e=0 ; 0 M 1 0 M M 2 < 0 R,i >= v R,i m νi =0 (Lee,Dev, RNM 13)

16 Realistic LR embedding of enhanced V N n Break Discrete sym. < φ i >= (II) δi 0 0 κ i n Leads naturally to m D = m 1 δ 1 1 m 2 δ 2 2 m 3 δ 3 3 MR = with δ i κ i 0 M 1 o M 1 δm M 2 by sym. δ i, i m i à m e = 0; m νij δ i j M i, δ iδ j M i, i j M i ev

17 Model as theory of leptons: Inputs and outputs n Model has 12 parameters: n Outputs: 3 charged lepton masses, 3 nu masses, 3 mixing angles+must satisfy unitarity constraints on 9 V i N j V er 12 µ 3e + which enters into n Hence predictive and testable!!

18 NEUTRINO FITS AND ENHANCED V N -TYPICAL SOLN. D =. R = V N 10 2 ( Lee, Dev, RNM 13)

19 Current constraints on for sub-tev M N V N Constraints: NA K --> e " U en 2 M N TeV 1 V e4 2 U µn Bounds from LHC Higgs decay to (Dev, Francischini, RNM 12) PS 191! --> e " CHARM m 4 (GeV) L3 DELPHI 0"## (Atre, Han, Pascoli, Zhang) e + e E T from most relevant for seesaw pp h N N W +,Z + ν

20 Testing in Colliders: SM Seesaw n Signal of SM seesaw: ± ± jj Golden channel V N 2 Signal strength depends on how big n V N typically tiny; V N n Even if it is big, less effective for M N > 200 GeV is: (del Aguila, Aguilar Saavedra)

21 Situation changes with LR seesaw: n New contribution via WR production: n Subsequent N-decay via (a) (b) W R exchange n Generic type I n Dominant graph(b) (RR diagram) θ N << 10 3 ν, < 4 MW R TeV νn n Same signal: valid for M N >> 200 GeV. ud W R l mixing and/or (a) negligible; N l ± jj (Keung, Senjanovic 82) + N

22 Current LHC analysis: only W R graph but not large V l N n Current limits from CMS, ATLAS TeV; n Theory papers: Datta, Guchait,Roy; A.Ferrari et al., S. N. Gninenko, M. M. Kirsanov, N. V. Krasnikov and V. A. Matveev, A.Maiezza, M.Nemevsek, F.Nesti and G.Senjanovic, Y.Zhang;V.Tello, M.Nemevsek, F.Nesti, G.Senjanovic and F.Vissani; J.Chakrabortty, J.Gluza, R.Sevillano and R.Szafron; P.Das, F.F.Deppisch, O.Kittel and J.W.F.Valle; T. Han, I. Lewis, R. Ruiz, Z. Si; Joaquim, Aguilar-Saavedra; n 14-TeV LHC reach for M 6 TeV with 300 fb -1

23 New graph for golden channel with large V N V N can be probed: n New graphs can dominate WR signal (Chen, Dev, RNM arxiv: PRD) q q W R + N; N W L (RL diagram) n Flavor dependence will probe Dirac mass M D profile:

24 Domains where mixing dominates over RR n Phase diagram: n Relative signal strength: RR vs RL: (mu channel)

25 Distinguishing RR from RL n Dilepton invariant mass plots: (Han, Lewis, Ruiz, Si)

26 CLFV in left-right seesaw n New contribution to CLFV for generic seesaw from in LRSM(I) (Riazuddin, Marshak, RNM 81; Cirigliano,Kurylov,Musolf,Vogel 04) B(µ eγ) < M N1 M N2 = 400 GeV B(µ e )= n <10-12 (M 2 =100 GeV) à Can probe W R and M N to TeV scale!!

27 Large V N n New graphs: (Pilaftsis; de Gouvea; Alonso, Gavela, Dhen, Hambye; ) and µ e + γ V µn N V en n Predictions of the model n Testable in the current round Testable next round e.g. PJX

28 (i) New Higgs fields: Scalar spectrum n They track the seesaw profile and N spectrum: n Decays n Have new effects on ++, +, 0 f αβ α β ++ µ 3e f ee f eµ ββ 0ν f ee v R M 2 M 4 W R (ii) Sub-TeV lepto-philic SM like Higgs tests (iii) Analog of SM Higgs: S Re( 0 R)

29 LHC limits n Pair production: cross section ~ fb at 350 GeV mass pp ++ This model: ++ e + µ + M > 450 GeV

30 Why sub-tev leptophilic SM-Like Higgs? n [Z 4 ] 3 family sym for leptons allows only terms in Higgs potential of form: λ a Tr[φ a φ a φ a φ a ] n As λ a 0, Z 4 gets promoted to U(1) a so that EWSB leads to Goldstone states. Their masses are therefore of order λ a κ 2 a and hence sub-tev. n They couple only to leptons- hence lepto-philic!! n LHC: σ(pp Z AH) 50 fb 4τ, 4µ final states (Aoki, Kanemura,Tsumura,Yagyu)

31 Conclusion: n Seesaw: Compelling big picture for nu masses; A new Left-right model provides a natural TeV scale UV completion of seesaw with large! V N n LHC could probe both Majorana mass as well as non-generic m D via + + jj mode. --Has 2 components: RR and RL due to V N ; can be separated allowing a test of such models!! n The set of models we predict and slightly below the current limits µ + N e + N µ e + γ n Sub-TeV SM like leptophilic Higgs states.

32 Extra slides.

33 New Higgs Effects in LR seesaw (i) Extra Higgs doublet: M H in multi-tev range. (ii) Triplet Higgs: δ ++ ββ 0ν L, R n in decay:(rnm, Vergados 81; piccioto, Zahir 82; lnemesvek, Nesti, Senjanovic, Tello, Vissani 12; Goswami et al;12; Awasthi,Parida,Patra 12; Barry,Rodejohann 12) M N n GeV -1 M 2 δ (for M WR =3 TeV)

34 n. Future Sensitivities

35 Beyond left-right : Quark-lepton Unif. n If Q-L unified at the seesaw scale, a model is SU ( 2) SU (2) SU (4) L R c à SU(4) generalization of the seesaw Higgs field partners qq connecting to quarks: à leads to neutron-anti-neutron. R has oscillation: (Mohapatra,Marshak 80) à No proton decay. -Example of nu mass-nnbar connection! f 3 v BL M! 6 observable for TeV sextets

36 Baryogenesis constraints n If NN-bar is observable, it will erase all pre-existing baryon asymmetry: need to generate baryons below weak scale: n Baryogenesis via higher dim operators: Post-sphaleron baryogenesis:(babu,nasri, RNM 07) n upper bound on Nnbar transition time < 5x10 10 sec. (Babu,Dev,Fortes,RNM arxiv: ) n Predicts ~TeV color sextet fields for LHC.

37 n CLFV that directly relates to neutrino Majorana mass µ eγ,µ 3e, µ e conserve L and are not true tests of Majorana nu mass. n However n Flavor analog of decay are µ e +,µ µ + L = 0 B(µ Ti e + Ca) ββ 0ν n Small in minimal type I n Other related processes: K + π e + e +, π e + µ +

38 V l N constraints from 125 GeV Higgs for >100 GeV M N n 125 Higgs bound on L h = h ν νnh à LHC Higgs search final states à V Npp h N N W e + e E T +,Z + ν (Dev, Franceschini, RNM 12) n Bounds very weak for >100 GeV N!!

39 WR production cross section at LHC n. Ginienko et al.

40 LR Higgs induced CLFV : Generic case (I) n (V. Tello,Nemevsek,Nesti,Senjanovic,Vissani 12; Cirigliano, Kurylov,Ramsey-Musolf, Vogel 04) n Loops involving and lead to µ e Au à, δ ++ δ + µ eγ n Bounds the mass ratio: M N /M n (Tello,..) Muonium-anti-muonium osc. Unique signature G M PSI Limit : M f eef µµ 8M G F 10 3

41 Properties of Seesaw-Higgs S Re( 0 R) n Production: pp Z Z + S σ n Decay: S Zf f,zz,hh S µ + µ,e + e, τ + τ n Displaced vertices for some range of parameters

42 Maximally testable seesaw n Has both M N sub-tev-tev ; large. n Situation in generic models with (i) m ν (h νv wk ) 2 M N ~.1 ev à V N M N TeV h ν 10 5 (ii) Small h ν à V N = h νv wk M N mν M N 10 6

43 Other tests of TeV WR: manifestation in ββ 0ν n Usual light Majorana nu contribution: IH n Current limits: NH

44 TeV WR manifesting in ββ 0ν n ) W R contribution- generic LR models (RNM, Senjanovic 79; (Nemevsek, Nesti,Tello, Senjanovic,12 Dev, Goswami, Mitra, Rodejohann 13) +LR+ Δ (LL) ββ 0ν n Nonzero signal for + NH à could be TeV WR n This modelà contribution small!!