Seesaw at LHC. Manimala Mitra. Institute of Physics (IOP), Bhubaneswar. Nu HoRIzons VII, HRI, Allahabad 22/02/2018

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1 Seesaw at LHC Manimala Mitra Institute of Physics (IOP), Bhubaneswar Nu HoRIzons VII, HRI, Allahabad 22/02/2018

Neutrino Mass and Mixing: ev neutrino mass and mixing from oscillation and non-oscillation experiments m 2 21 =(6.93 7.97) 5 ev 2 m 2 31 =(2.37 2.63) 3 ev 2 sin 2 12 =0.25 0.35, sin 2 23 =0.37 0.

2 Neutrino Mass and Mixing: ev neutrino mass and mixing from oscillation and non-oscillation experiments m 2 21 =( ) 5 ev 2 m 2 31 =( ) 3 ev 2 sin 2 12 = , sin 2 23 = Large angle Non-zero , (Fogli, Lisi, 2016) F. Capozzi et al., 2017 (DAYA BAY, RENO) Bound from cosmology m i < O( ) ( Planck Collaboration, arxiv ) Relaxed bound from m = decay s X U ei 2 m 2 i < 2.3 ev i (Mainz, Troitzk) 2

3 Majorana mass mν Major T C 1 ν Puzzles not standard model gauge invariant Beyond The Standard Model (BSM) theory is necessary - Underlying theory of neutrino mass generation! At present no experimental evidence! Neutrinos are electromagnetic charge neutral Dirac or Majorana? Majorana particle it s own antiparticle. Others: Neutrino mass hierarchy-normal vs Inverted, CP Neutrino Oscillation phase, fermion mass hierarchy more Normal vs Inverted Mass hierarchy Manimala Mitra CP violation, Ambiguity in 23 New physics Neutrinos and BSM Searches 3

4 Seesaw Neutrinos ev mass?? Majorana mass from d=5 operator Seesaw Minkowski, 1977; Gell-mann, Raymond, Slansky- 1979, Yanagida 1979, Mohapatra, Senjanovic 1980 L f (φ,χ ) at higher scale χ integrated out L eff (φ) at lower scale Ô 5 = LLHH M Violates B L by 2 units Gauge invariance (Weinberg, PRL 43, 1979) y 2 LL H H M m ν = ν T C 1 ν m ν y2 v 2 M ev neutrino due to heavy M 4

5 Contd: Contd: Type-I SM gauge singlet Type-II SU(2) Triplet, Y =2 Type-III SU(2) Triplet, Y =0 H H R Gauge interaction H H H H N R µ Y N Y N Σ R Y Σ Y Σ Y L L interaction of N with other SM particles is proportional to the active-sterile mixing H L H L L H ++ Doubly charged Higgs L V ln Suppressed m D M L L Heavy modes integrate out Minkowski, 1977; Gell-mann, Raymond, Slansky- 1979, Yanagida 1979, Mohapatra, Senjanovic 1980; Magg, Wetterich, 1980; Foot et al.,

6 Quasi-degenerate neutrinos M N1,2 = M ± µ Unsuppressed mixing m D M Inverse Seesaw σ large M ν = 0 m D 0 m D 0 M 0 M µ Others µ 0 Mohapatra, Valle, 1986 For µ m D <M m ν µ m D 2 M µ Lepton number violation. µ 0= m enhances 0 and lepton enhanced number lepton symmetry n R-parity violating supersymmetry-( Masiero, 1982; Santamaria, Valle, 1987; Romao, Valle, 1992; Borzumati, 1996; B. Mukhopadhyaya, S Roy, F Vissani, PLB 1998, Anjan S Joshipura, Sudhir K Vempati, PRD 60, ) Loop generated mass? Radiative inverse seesaw (A. Zee, 1980; A. Zee, K. S. Babu 1988; D, Choudhury et al., PRD 1994; Dev, Pilaftsis, ) Others dimension 7 (LLHH)HH 2009) Λ 3 operators etc (K.S. Babu et al.,, 6

7 Higher Dimensional Probe of Seesaw Babu-Nandi-Tavartkiladze (BNT) Model Scalar isospin 3/2 quadruplet (F) Tree level (d=7) 1-loop level (d=5) Vecor like triplet (S) Slide courtesy: Tanmoy Mondal Rich Phenomenology with Multi-lepton &nal states Small v F K. S. Babu, S. Nandi, and Zurab Tavartkiladze, PRD (Rap Comm) 80, (R) (2009) Gulab Bambhaniya, Joydeep Chakrabortty, Srubabati Goswami, and Partha Konar, PRD, 88, (2013) 7

8 Left-Right symmetric theory Type-I and Type-II Pati; Salam; Mohapatra, Senjanović, 74, 75 Enlarged gauge sector SU(2) L SU(2) R U(1) B L Parity symmetric theory parity violating SM Two Higgs triplet L =(3, 1, 2), R =(1, 3, 2). R breaks the SU(2) R U(1) B L U(1) Y Sterile neutrino N is part of the gauge multiplet ( N e Additional gauge bosons W R and Z. M WR R ) R Natural way to embed the sterile neutrinos N,W 0,Z 0, ++ Phenomenology 8

Model Building Experimental Probe Low Energy 0 2, µ! e,µ!

9 Experimental probe: Flavor physics probe B physics anomalies, Collider signatures pp, e + e, Neutrino Mass Model Building Experimental Probe Low Energy 0 2, µ! e,µ! 3e, µ e Astroparticle Probe Theory Constraints Dark matter, leptogenesis, 9

10 utline: Sterile Neutrino: Heavy Neutrino N Key ingredients behind neutrino mass generation Heavy neutrino mass M ev- GUT scale Detection Collider, Oscillation, Peak searches, Kink, (ββ) 0ν -decay,... And LFV processes, Non-unitary effect,...

11 Sterile Neutrinos Charged current g 2 lγ µ W µ θ α N R ; N.C g 2c w νγ µ Z µ θ α N R ; Higgs gm 2M w νθ α N R H Interaction depends on the mass M and mixing θ α. m D M Multilepton, multijet final states From arxiv: , S. Antusch et al., 11

12 Bounds Limits on active-sterile neutrino mixing V from neutrino mass, (ββ) 0ν -decay, beam dump experiments and others... Light neutrino mass V 5 / M. For M =0GeV, V 6 extremely small Experimental constraints (ββ) 0ν -decay, beam dump experiments. (ββ) 0ν -decay stringent. VeN PS191 K eν NA3 CHARM L3 DELPHI GERDA M N GeV Mitra, Pascoli, Wong, 2013 ; Atre et al., JHEP 0905, 030(2009); Mitra at el,, NPB 856, 26(2012) 12

13 Contd NA3 CHARM II -1 NOMAD V µ K --> µ ν PS 191 FMMF BEBC NuTeV m 4 (GeV) L3 DELPHI V τ Based on CHARM DELPHI m 4 (GeV) Atre et al., JHEP 0905, 030(2009) Severe constraint from light neutrino mass possible to escape in presence of cancellation in neutrino mass matrix M ν = MD T M 1 R M D or enhanced global symmetry. V en is tightly constrained from (ββ) 0ν -decay upto TeV scale The muon and tau sector are less constrained collider prospect 13

14 Contd 5 σ / V ln 2 (pb) pp! l ± N m N m N 0 GeV collider sensitive Heavy Majorana Decay To gauge bosons N lw and N Zν. ToHiggsN νh Atre et al., JHEP 0905, 030(2009) 14

Collider signatures lepton channels Like sign/ different flavor diliptons l ± l ± /l ± l +2j Trilepton channels l ± l l ± For Dirac neutrinos N R Lepton number violating l ± l ± Proof of heavy

15 Collider signatures lepton channels Like sign/ different flavor diliptons l ± l ± /l ± l +2j Trilepton channels l ± l l ± For Dirac neutrinos N R Lepton number violating l ± l ± Proof of heavy Majorana neutrinos N R Atre et al., JHEP 0905, 030(2009); Aguila et al., NPB 813, 2009; Aguila et al., 2007; Aguila et al., PLB 672, 2009; Arhib et al., 20,... 3l+X search CMS collaboration, arxiv l ± l ± + jj fb Bound 1 from ATLAS from CMS pp-1 µµ +2j V N µ -1 (8 TeV) CL Expected s CL Expected ± 1σ s CL Expected ± 2σ s CL Observed s L3 DELPHI CMS 7 TeV m (GeV) Manimala Mitra Heavy Neutrinos at Colliders-Direct Detection N / 26 CMS collaboration,

16 Boosted regime: Boosted RH neutrino N m N <M W Production from meson decay N W ± `± B ± D 0 `± N m N <B ± Three body decays of N to ljj, l + l 16

17 Lepton Jet: N! µ + µ µ µ Lepton jet+ µ p p Collimated µ + µ Brian Shuve et al., Lepton jet / E T µj Sourabh Dube et al., Arindam Das et al.,

18 Discovery Reach: »VmN SHiP proposal Lepton jet search Trilepton search M N HGeVL Displaced lepton jet search Prompt trilepton search LHC 13 TeV m N <M W Brian Shuve et al.,

19 High Mass Sterile Neutrino: pp! W ±! µ ± N,N! µ W ±,W ±! J Opposite charged lepton + Fat-jet q W ± µ ± N µ W ± j 1 J Bharadwaj et al., arxiv q M N >> M W j 2 Most challenging corner due to large backgrounds dn (GeV -1 ) dmj 0 0. M N = 800 GeV 0.08 M N = 400 GeV Z + j, t t, V V + j 1 N M J 0 (GeV) substructure variable 19

20 Discovery Reach: LHC 13 TeV 3000 fb Discovery reach with substructure analysis ( )- ( )- ( )- μ ( )-μμ ( )-μμ ( ) ( ) Bharadwaj et al., arxiv ( ) High mass range M N >> M W 20

Alternative possibilities The basic framework is simple, but conservative. Production and decay of heavy neutrinos through active-strile neutrino mixing.

21 Alternative possibilities The basic framework is simple, but conservative. Production and decay of heavy neutrinos through active-strile neutrino mixing. Stringent constraints on the mixing parameter A large mixing requires cancellation in the light neutrino mass matrix Models with extended gauge sectors or particle contents Higgs triplet Gauged B-L production via z Left-Right symmetry production via W R Two Higgs doublet model Large Yukawa 21

22 Type-II seesaw (3, 2) H ++,H +,A 0,H 0 2,H0 1 LL Light neutrino mass M ν = y v. H ++ l l M ν /v. Γ ( H ++ e + i e+ j ) = M ij ν 2 8π(1 + δ ij )v 2 M H ++ Γ ( H ++ W + W +) = v 2 M3 H ++ 4πv M 2 W M 2 H ++ 1/2 1 2M W 2 M 2 H ++ 2 Different v distinctive H ++,H + branching v 4 GeV H ++ W + W + evading LHC bound Dominant 3 body Br H AB H lν H 3 body H WZ, Wh H tb v GeV 22

GeV in the 4e channel ATLAS-CONF-2016-051

23 Limit from LHC l + I l + I q Z 0 /γ Φ ++ l + J q W ± Φ ++ l + J q Φ l K q Φ l K l L ν L M H GeV in the 4e channel ATLAS-CONF Combined bound M H (0% Br)-small v HIG pas23

24 LFV signatures LFV signatures LFV signatures µ 3e, µ eγ, τ µγ, τ 3µ Branching ratio of µ 3e 12 Branching ratio of µ eγ Tightly constrained τ sector is less constrained τ 3µ, eµµ, eγ, µγ. τ 3µ, eµµ 8 Γ(τ µ ± µ µ )= m5 τ 192π 3 C τµµµ 2 C τµµµ = Y τµy µµ m 2 ±± = M ν (τ,µ)m ν (µ,µ) 2v 2 m2 ±± Higgs triplet Manimala Mitra Neutrinos and BSM Searches 24

25 Contd: LFV limits τ ± µ ± µ µ Experiment Current Projected Belle (4.7 ) BaBar FCC-ee (5 ) 12 LHCb (1.5 11) 9 ATLAS ( ) 9 FCC-hh (3 30) τ ± e µ ± µ ± τ e ± µ µ τ e µ µ ± Experiment Current Projected Current Projected Belle ( ) (5.9 12) BaBar FCC-ee (5 ) 12 (5 ) 12 The present limit 8. LHCb limit similar to Belle. The future sensitivity TeV LHC can give stringent limit. LHC limits 8TeV.Futurelimitswith13TeV,3ab 1 for ATLAS and 50 ab 1 with LHCb. 25

26 Other searches: Same sign tetra lepton pp! l ± l ± l ± l ± + X pp! W! H ± H 0 /A 0 ; pp! Z! H 0 A 0 H ±! H ±± W,H 0 /A 0! H ± W Total Br l ± l ± l ± l ± + X M H ±± M H ± M (in GeV) 0 temp.out u 1:2: v (in GeV) Eung Jin Chun et al., arxiv: v

Discovery prospect: M H ±± 5 4 3 2 1 = 400 GeV LHC14 14TeV.out u 1:2:3-5 -4-3 Same sign tetra lepton cross-section 6 5 4 3 2 1 0 Large triplet vev H ±±! W ± W ± Biswarup Mukhopadhyaya et al.

27 Discovery prospect: M H ±± = 400 GeV LHC14 14TeV.out u 1:2: Same sign tetra lepton cross-section Large triplet vev H ±±! W ± W ± Biswarup Mukhopadhyaya et al., arxiv: S. Kanemura et al., arxiv: M. Mitra et al., arxiv: D. K Ghosh et al., arxiv: Multilepton+MET, Triplet vev 14TeV.out u 1:2:4 Eung Jin Chun et al., arxiv: dilepton+multi-jet Doubly charged Higgsino Babu, Patra, Rai, arxiv: arxiv:

28 Left Right Symmetry Searches same sign dilepton+jets A number Collider of processes direct and indirect 0νββ,LFV l i Neutrinoless l j γ,l i l j l k l l Double, colliderbeta searches. Decay Talk by Srubabati Meson Decays Talk by Nita charged lepton 0νββ 2d flavor violation 2u +2e Keung, Senjanović, PRL, 83 28

Complementarity to LHC Complementarity to LHC P. S. Bhupal Dev, S. Goswami, M. Mitra and W. Rodejohann, Phys.Rev.D88,091301(2013) R.Awasthi, A. Dasgupta and M. Mitra, arxiv: 1607.

29 Complementarity to LHC Complementarity to LHC P. S. Bhupal Dev, S. Goswami, M. Mitra and W. Rodejohann, Phys.Rev.D88,091301(2013) R.Awasthi, A. Dasgupta and M. Mitra, arxiv: ) The contour is M N< = p2 Φ(oscillation parameters) M W 4 m ν R exp m ν ee Future 0νββ m N ee = ev. 0νββ Complementary to LHC However, LHC puts stringent bound in the TeV range 29

13 TeV Result: pp! W R! l ± N! l ± l ± jj -1 35.

30 13 TeV Result: pp! W R! l ± N! l ± l ± jj fb (13 TeV) (GeV) m NR CMS Preliminary Expected - 68% expected + 68% expected Observed > m NR m WR % CL upper limit on cross section (fb) Same flavour, OS+SS combined CMS-PAS-EXO (GeV) m WR TeV 30

31 Contd: contd M N and M WR are hierarchical l 2 is collimated with the jets Alternate signal topology l + j fat Manimala Mitra, Richard Ruiz, Darren J. Scott, and Michael Spannowsky - PRD 94, , 2016 u i W R N W R u m l 2 dn l + J d j l 1 Simple 2 body topology The transverse momentum p T (l, j fat ) M WR /2 The separation between l 2 and q,q will be small. 31

32 Contd: 1/σ dσ/d R [0.05 / bin] m M N W R 5% = 1% % 1/σ dσ/d R [0.05 / bin] m M N W R 5% = 1% % 13 TeV LHC R qq min R lq M N M WR 1% R <0.3 ATLAS 13 TeV search with R >0.3 for l ± l ± jj is not applicable Manimala Mitra Neutrinos and BSM Searches 32

33 Contd: 1/σ dσ/dm [1 / 30 GeV] (M,m ) = W R N (3 TeV, 150 GeV) (3 TeV, 30 GeV) (3 TeV, 300 GeV) (4 TeV, 400 GeV) (5 TeV, 500 GeV) m j [GeV] N Signal pp W R e + j fat The l and j fat invariant mass should peak at M WR Manimala Mitra Neutrinos and BSM Searches 33

34 Contd: contd [GeV] m N m N =M WR ATLAS 95% CL Exclusion, 8 TeV 20.3 fb JHEP07(2015)162 [ ] fb [TeV] M WR The hierarchical mass regime to probe -1 m M N W R -1 fb 13 TeV LHC = fb Mitra, Ruiz, Scott, Spannowsky,

35 LNV Higgs decays Heavy neutrino from Higgs decays pp! l ± l ± +4j h N W R l ± j j N W R j LNV signal A. Maiezza et al., arxiv: j l ± j j pp! l ± l ± l ± l ± + nj h N N N N l ± 4 j j l ± l ± 3 2 j j l ± 1 M. Nemevsek, arxiv: j j 35

36 Discovery Reach {{ j j sin q = % j j sin q = 40% s = 13 TeV L = 0 fb -1 1 cm m N in GeV s 3 s 2 s sin q M WR = TeV cm 1 m 15 0n2b m N A. Maiezza et al., arxiv: W' Æ {n search M WR in TeV s 3 s 2 s M WR =3 TeV

37 Summary Simplest sterile neutrino can be tested in low energy, collider experiments 1 GeV-00 GeV constrained from LHC Higgs triplet, bound exists upto 820 GeV on doubly charged Higgs, more on LFV searches. Left-right symmetry, RH neutrino, RH gauge bosons, Higgs triplet LNV signals Challenging corners to probe 37

38 LNV Higgs decays 0 s = 13 TeV L = 0 fb -1 q = % M WR = 3 TeV background apple of events signal m N =40 GeV WZ+ ZZ+ W ± W ± jj+ tt 1 signal m N =20 GeV muon d T in mm pp! µ ± µ ± +4j Displaced RH neutrino decay 38

39 Thank You 39

40 »VmN ct N = m ct N = cm ct N = 0.1 mm M N HGeVL

41 Summary Plot (Electron Sector) V en π eν K eeπ PS191 K eν NA3 Belle L3 DELPHI -9 FCC-ee M N (GeV) Slide courtesy Bhupal Dev [Atre, Han, Pascoli, Zhang (JHEP 09); Deppisch, BD, Pilaftsis (NJP 15)] 41

42 Summary Plot (Muon Sector) VμN PS191 μν K μμπ - NA3 EWPD L3 DELPHI -9 FCC-ee M N (GeV) [Atre, Han, Pascoli, Zhang (JHEP 09); Deppisch, BD, Pilaftsis (NJP 15)] New limits from NA48/2 Slide courtesy Bhupal Dev

43 Sterile interaction Heavy neutrino N R Gauge singlet Does not have any gauge interaction Yukawa interaction L ν = Y ν L HN R N c R MN R +h.c N R Majorana M is Lepton Number Violating ( 0 MD Mass matrix M ν = MD T M ) For M M D active-sterile mixing V = M D M

44 σ [fb] LO 4 3 σ / σ ± pp W R + X 13 TeV LHC LO σ NLO+NNLL BR BR m M N W R = 0.1 NLO+NNLL w./ PDF Unc. M WR [TeV] NLO + NNLL w./ PDF Unc. NLO NLO w./ PDF Unc.

45 σ [fb] LO σ / σ m M N W R = 0.1 ± pp W R + X 0 TeV VLHC NLO LO NLO + NNLL w./ PDF Unc. σ NLO+NNLL BR BR 1.6 NLO+NNLL w/. PDF Unc. NLO w/. PDF Unc M WR [TeV]

46 [fb/ GeV] W R =3TeV N =30GeV W R =3TeV N =150GeV W R =3TeV N =300GeV W R =4TeV N =400GeV W R =5TeV N =500GeV background W+jet dσ/dmwr m WR [GeV]

47 4-1 ab ] Luminosity [fb ab -1 0 fb 5σ 3σ M WR 0 TeV pp W R e ± j N [TeV] m M N W R =0.1

48 3-1 1 ab ] Luminosity [fb σ -1 0 fb 3σ M WR 13 TeV pp W R e ± j N [TeV] m M N W R =0.1

49 [GeV] m N m N =M W R pb 0 TeV VLHC ATLAS 95% CL -1 Exclusion, 8 TeV 20.3 fb JHEP07(2015)162 [ ] -1 0 fb m M N W R = ab 5 15 [TeV] M WR

50 Type-I and Type-III Type-I Type-III Majorana neutrino N R Gauge singlet L f = Y ν L HN R N R c MN R +h.c Active-sterile mixing V = m D M 1 SU(2) triplet with hypercharge Y =0, Σ +, Σ, Σ 0 [ ] L Y = Y Σij H Σ Ri L j + h.c M Σ ij Tr [ ] Σ Ri Σ C R + h.c. + Σ /DΣ j Σ has gauge interaction W Σ ± Σ 0,ZΣ ± Σ suppressed production M, M Σ are Lepton Number Violating Unsuppressed production For M M D = Y ν v Light neutrino mass m ν m T D M 1 m D For M 0GeV V 6 Manimala Mitra Neutrinos and BSM Searches

51 Type-II and Inverse Seesaw Higgs triplet, (3,2) ( δ = + / 2 δ ++ ) δ 0 δ + / 2 he gauge invariant Lagrangian Light neutrino mass m ν y v v = v 2 µ. M 2 Lepton number violation y,µ L Y = y L T L C iτ 2 L L + µ H T iτ 2 H + M Tr( ) + h.c+... Doubly charged Higgs δ ++ Gauge interaction Large production Inverse Seesaw - Quasi-degenerate neutrinos M N1,2 = M ± µ Unsuppressed mixing m D M σ large M ν = 0 m D 0 m D 0 M 0 M µ For µ m D <M m ν µ m D M 2 Mohapatra, Valle, 1986 µ Lepton number violation. µ 0= m ν 0 and enhanced lepton number symmetry. Inverse seesaw Manimala Mitra Neutrinos and BSM Searches

52 Testing Type-I Seesaw Experimentally Similar signature for Inverse Seesaw, Type-III Seesaw Majorana Nature Slide courtesy K. S. Babu 52

53 dn d ( 21) 1 N Z+j tt - +j WW+j J 0 12

University College London. Frank Deppisch. University College London

University College London. Frank Deppisch. University College London Frank Deppisch f.deppisch@ucl.ac.uk University College London 17 th Lomonosov Conference Moscow 20-26/08/2015 Two possibilities to define fermion mass ν R ν L ν L = ν L ν R ν R = ν R ν L Dirac mass analogous