J. C. Vasquez CCTVal & USM

Transcription

1 Maorana Higgses at Colliders arxiv: J. C. Vasquez CCTVal & USM ( Work in collaboration with F. esti and M. emevsek) University of Massachusetts, October 2017

2 Outline The minimal LR model Decay modes of the Higges - Decays to fermions - Decays to bosons - Decays to scalars Main production channels at the LHC - Single production - Associated and Pair production Signals at the LHC Summary and connection Conclusions

3 Testing the Higgs mechanism In the SM: For neutrino mass origin? Image taken from CMS public results It does for neutrino masses what the SM does for charged fermion masses

4 Testing the Higgs mechanism In the SM: For neutrino mass origin? Image taken from CMS public results Fixed in terms of heavy and light neutrino masses in LR model. o type I ambiguity! J. A. Casas and A. Ibarra, ucl. Phys. B618, 171 (2001) What LHC can do for testing H spontaneous Mass generation???

5 Introduction and motivation The minimal Left-Right Symmetric model Pati and Salam, Phys. Rev. D 10, 275 (1974); R.. Mohapatra and Pati, Phys. Rev. D 11, 2558 (1975); Senanovic and Mohapatra, Phys. Rev. D 12, 1502 (1975); Senanovic, ucl. Phys. B153, 334 (1979). Parity is a symmetry of nature, spontaneously broken at higher energy scales. As a consequence, the near maximality of parity violation is as low energy phenomenon that disappears at high energies. Gauge group: times a LR symmetry that may be parity or charge-conugation. Quarks and leptons are assigned: 5

6 One bi-doublet and two triplets The Higgs sector of the model Lepton masses come from the interaction Minkowski, Phys. Lett. 67B, 421 (1977); Mohapatra and Senanovic, Phys. Rev. Lett. 44, 912 (1980). The field v.e.v s are The neutrinos mass terms are: 6

7 LR model as a complete model of neutrino masses In the type I see-saw: Impossibility of determining the Dirac mass in terms of heavy and light neutrino mass matrices (without any additional input). In this case: and O is an arbitrary orthogonal complex matrix whose elements are not limited from above. J. A. Casas and A. Ibarra, ucl. Phys. B618, 171 (2001) In the LR model O is fixed and the determination of the leptonic mixing is fundamental! (emevsek, Senanovic, Tello (2013). arxiv: ) 7

8 Maorana Higges 8

9 Maorana Higges In terms of the h and Delta masses and mixings we have We consider very low Delta mass, hence one loop corrections becomes important. This is similar to previous studies in SM Higgs boson. 9

10 Spontaneous mass generation of H s (Scalar sector) 0 4 What LHC can do to test This hypothesis? Strategy for searches Mass reach? Search Channels? 10

11 Signals at the LHC Single production l ± 2 (h) Pair production l ± 1 h l ± 4 l ± l ± 3 2 l ± 1 11

12 Decay modes of the Higges Decays to Heavy neutrinos Decays to SM fermions LFV decays (1 loop, suppressed not relevant) 12

13 Decay modes of the Higges Decays to Heavy neutrinos 13

14 Decay modes of the Higges Decays to Gauge Bosons The di-photon and channels Decays to Scalars 14

15 All decay modes in one plot ( s 2 gg!! ' gg!h (m ), m. 2M W, (!), m & 2M W. c 2 h (1) 15

16 Production at the LHC Single production and pair production sggædbrdæ in fb s = 13 TeV M WR = 5 TeV s q = 85, 20, 40<% in fb 2 sggæhbrhæddbr DÆ s = 13 TeV M WR = 11 TeV s q = H5,10,20L% m D in GeV m D in GeV 16

17 Production at the LHC Associated and pair production 17

18 1-loop Effective Potential V eff =(C 1 ) v 4 R +4 1 v 2 R C 3 v R C 4 0, (1) C= Y 4. Requiring absolute stability leads to the bound V eff (v R ) apple V eff (0) ) v (1) apple 7 tree level v 3 v ik denotes the trilinear couplings of the scalar potential

19 Loop corrections to the tri-linear couplings neutral v i H0+1L neutral vi in GeV md h h h h h D h D D m D in GeV h D D D D D D D D h D D Hflip ql m D = 100 GeV h h D M WR in TeV in GeV neutral v i H0+1L M WR = 4 TeV h D D h h h h h D D D D m D in GeV v hhh ' 3g h 2M WL v hh ' g h 4M WL v h ' g 4M WL h Tree level couplings m 2 h c 3 + s 3 v ' 3g 2M WL h m 2 c 3 s 3 i, i 2m 2 h + m 2 ( s c ) s 2, i m 2 h +2m 2 ( c + s ) s 2, i,

20 Loop corrections to the tri-linear couplings s 2 (0.05, 0.1), M WR =4TeV, m H = 17 TeV, r ++ =0.3 m ++ =1TeV R These values are chosen according to the perturbativity, B-meson and EPT done in arxiv: neutral v i H0+1L neutral vi in GeV md h h h h h D h D D h D D D D D D D D h D D Hflip ql m D in GeV m D = 100 GeV h h D M WR in TeV in GeV neutral v i H0+1L c (1) =1/ p 2(4 ) 2 (m H /v R ) 4, r ++ =(m ++, M WR = 4 TeV h D D h h h h h D D D D m D in GeV 1-loop couplings! 0 v (1) hhh ' c(1) v (1) hh ' c (1) 11 2 v R, 1 r ++ 3 v R, v (1) h ' c (1) ( r ++ ) v R, v (1) ' c (1) r 2 ++ v R. 0,+,++ /m H ) 2 L

21 Associated production

22 Signals at the LHC l ± 2 h l ± 4 l ± l ± 3 2 l ± 1 l ± 1 Signal generation: - Updated Feynrules model of LR - Event generation at LO with MadGraph 5, hadronization with Pythia 6 and Delphes 3 for detector simulation - The gluon fusion xsec was rescaled to the LO+LL QCD and LO EW value recommended in - Backgrounds: ttbar WZ and Zh (K=1.5) and ZZ, Wh, VVV, VVh (K=1.34) - Detector response: default Delphes card modified to with electrons and muons treated separately and with experimental triggering thresholds taken into account and taken from ATLAS-COF , arxiv: and ATL-DAQ- PUB

23 Signals at the LHC For Electrons: - Efficiencies of ATLAS-COF o electrons bellow pt < 6 GeV - Mono(di)-electron trigger of pt > 24(12) GeV - Tight (Loose) isolation < 0.06 (0.15) Because of these requirements the efficiency in the electron case is reduced with respect the muon case For Muons: - Efficiencies of arxiv: with 0 efficiency for pt < 5 GeV - For most of the parameter space the single muon trigger is the best with pt(mu1) > 20 GeV and for low Delta mass < 80 GeV the dimuon trigger with pt(mu2) > 10 GeV turns out to be better. - The overal selection efficiency for triggering goes from 10% for low masses and up to 80 % at mass of Delta of 160 GeV and heavy neutrino mass of 75 GeV - Again we apply tight and loose isolation to muons For Jets reconstruction we use the antikt algorithm with DR= 0.4 and minimun pt() = 20 GeV. Cuts, event counting and sensitivity estimates were performed with the help of MadAnalysis 23

24 l ± 2 ½ propability of LV signal with l ± 1 o flavor violation in the final state We include only electrons and muons in the final state We assume the leptonic mixing matrix to be diagonal We expect no b-ets in the final state 24

25 Basic cuts and Backgrounds For the event selection: - 2 same-sign, same flavor leptons and up to 3 ets - Missing - - Transverse mass - Invariant masses The selection effeciency is around 6% or less For the backgrounds we estimate the Jet Fake rates by augmenting the JetFakeParticle class for fake leptons rate estimates 25

26 JetFakes Validation We use the semi-empirical method presented in arxiv: It consists of 26

27 JetFakes Validation 27

28 Basic cuts and Backgrounds 28

29 Further signal characteristics 29

30 Displacement and sensitivity For H with EW masses there is a fairly long decay length Several theoretical and experimental works have been proposed for displaced vertices We adopt the quoted vertexing efficiency of 50% reported in CMS-PAS-SUS Required both leptons to be transversally displaced for signals with with lifetime longer than 1 mm l T > 0.1mm 30

31 h l ± 4 l ± l ± 3 2 l ± 1 Figure 7. Contours of estimated sensitivity (S/ S + B = 5) for the h 4 process in the electron and muon channels. The plots from left to right refer to the signal regions R #l L described in the text. The contours refer to different M WR, while s = 13 TeV,s θ =0.1 and the luminosity is 100 fb 1. The electron channel yields similar plots with a smaller sensitivity. JHEP04(201 31

32 Displaced region Displaced region Displaced region covers most of the parameter space 32

33 33

34 Conclusions If the masses of heavy neutrinos is generated spontaneusly, a Maorana Higgs boson should exist We study the Maorana Higgs boson collider phenomenology in the energy range accessible at the LHC and within the LR model, which is a complete model of neutrino masses and mixings We provide a road for experimental searches A substantial number of LV events can be produced only when its mass is below 160 GeV, beyond which the standard searches for scalar singlet apply There are two clean channel with two and four heavy production. While the former is partially covered by, the latter which features the breaking of lepton number by 4 units has no low energy counterpart One of the main result of this work, which is that with the combination of all channels the sensitivity is well beyond the 10 TeV range for the LR scale. Despite our effort to estimate the Lepton fake rate, this should be ideally estimated from data Tau leptons were not investigated due to experimental intricacies and backgrounds The observation in future leptonic colliders seems optimistic, with the possibility of producing a significant number of events In summary the Higgs portal provides a new frontier for LV searches at colliders and may be sensitive to high energy scales well into the TeV range 34

35 Thank you