Higgs decay to ZZ* on CEPC

Transcription

1 Higgs decay to ZZ* on CEPC

2 Outline Introduction on Higgs->ZZ* channel Analysis:result difficult Next move Plan table backup

3 Introduction H->ZZ* is very important for precise measurement of Higgs properties, especially for measurement of Higgs width. H->ZZ(ΓZ<-HZZ coupling(g Z<-absolute cross section of e + e - ->ZH<recoil mass techniques.

4 Introduction H->ZZ*:.7% Normalize to 5 ab - ZZ*\IniZ ll taus vv 4q k 9.4k v+q k 5.9k A good tool to develop all kinds of algorithms, reconstruction, etc. l+q v l+v l X+tau

5 Samples ZH events: Z_H->(µ + µ - (e + e - (vv(_inclusve, reconstructed by Arbor Path: /cefs/data/recdata/sig Standard Model BackGround: Fast simulation Path: /cefs/data/stdhep/background 5

6 Algorithm Fast simulation versus Full simulation Process:e + e - ->ZZ->vv The jet-processing package LCFIplus is used in full simulation samples, while the package FastJet is used in fast simulation. For both package, pseudo jets are clustered with ee_kt_algorithm, exclusively. Isolated lepton in is defined as a lepton dominating its neighbour cone space. The parameters are described in appendix. 6

7 Analysis Final Lepton Tau neutrin Quark BR 7%.5% 0% 70% luminosity: 5 ab - ZZ* ll taus vv 4q k 9.4k v+q k 5.9k l+q v l+v l X+tau since we treat Z and Z* as different particles, when ZZ* decay to different kinds of final states, the block spilt into two equal parts. 7

8 A promising channel: kinds of final state (fs ZZ*\IniZ µ + µ - e + e - vv 6 6 vv 6 6 Result on cut base(ra < 0% Needs more optimise for better result Difficult for now ZZ*\IniZ vv µµvv 6 vvµµ 6 eevv 6 vvee 6 µµ 6 µµ 6 ee 6 ee 6 8

9 ZZ*\IniZ e + e - µ + µ - vv 6 6 vv 6 Total The main background: e e -> e e ; + e - ± e -> e v e ; ev/tauv e e -> ZH-> e e bb final state E e e -> Tau Tau ; e e -> ZH-> e e WW*-> e e signal _sl _sl _sl _sl _sl _4q VisEn(0, Invariant mass of jets(, Invariant mass of leptons(7, npfos[4,85] difference of jets< Interanglr of jets(0.5, missingmass> VisEn< visible_p(8, Invariant mass of jets< leptons P(9, lead_exlep_en< abs(costheta< mina> RrecoMass of jets>

10 we can get a relative precision of 5.% from this single channel _sl _sl _sl _sl _sl µvµ event For we have 4 visible objects in final states, electrons and jets, boost them into their centre-of-mass frame. we define the smallest inter angle of electron-jet pair as mina, then define the inter angle of the rest pair as mina, this variable has a strong discriminating power to veto the e+e >vvjj events where the fake isolated leptons are always lie in the cone of jet, let mina be larger than mina Isolated lepton fake isolated lepton

11 Total signa l _sl _sl _sl _sl _sl final_state npfos(5, Visible Energy(9, Invariant mass of jets(, Invariant mass of Muons (76, difference of jets< missingmass> Visible Energy< Invariant mass of jets< Leading_extra_En < missing mass > The main background: e + e - -> Tau + Tau - ; e + e - -> µ ± vµ; e + e - -> ZH-> e + e - WW*-> Tauv All of these events are ZH->µµWW*- >µµ Tau v ZZ*\IniZ e + e - µ + µ - vv 6 6 vv 6 6 we can get a relative precision of.6% from this single channel.

12 signal _sl _sl _sl _sl _sl final_state Missingmass(58, Invariant mass of Muons is larger than that of jets Invariant mass of jets (, Invariant mass of muons(60, Interangle between jets and muons< The main background: e + e - -> Tau + Tau - ; e + e - -> vv; e + e - -> µ ± v µ ; e + e - -> ZH-> e + e - WW*-> Tauv All of these events includes Tau ZZ*\InitZ vv µµ 6 µµ 6 ee 6 ee 6

13 signal _sl _sl _sl _sl _sl final_state Missingmass(58, Invariant mass of Muons is less than that of jets mina&mina Invariant mass of jets(5, Invariant mass of muons(6, Interangle of jets and muons recoil mass of jets> visible_mass(, All of these events includes Tau ZZ*\InitZ vv µµ 6 µµ 6 ee 6 ee 6 we can get a relative precision of 8.6% from this single channel.

14 interangle between leptons and Jets Combine leptons 4-momentum as lepton_p, then combine the rest of particle flow objects 4-momentum before jetclustering as jet_p. Define the inter angle between lepton_p and jet_p as angle_lj. In order to veto the e+e >lljj events where lepton_p and jet_p are likely to be back-to-back mina.5 sig.5 vv mina mina.5 BackGround mina&mina mina

15 signal _sl _sl _sl _sl _sl (4q (%(f final state E missing-mass(58, Invariant mass of Muons is larger than that of jets Invariant mass of jets and muons mina> mina(0.66, recoil mass of muons(8, Interangle of jets and muons < recoil mass of jets(78, abs(costheta< visible mass(4, missing mass (84, The main background: e + e - -> e + e - ; e + e - -> Tau + Tau - ; e + e - -> e ± v e ; e + e - -> ZH-> e + e - WW*-> e + e - ev/tauv e + e - -> ZH-> e + e - bb ZZ*\InitZ vv µµ 6 µµ 6 ee 6 ee 6 5 we can get a relative precision of 8.6% from this single channel.

16 final_s tate Presel ection signal _sl _sl _sl _sl _sl 4q q µµvv vvµµ H->TauTau:99 H->WW*->µvtauv:9 tauvtauv:4 µvµv:769 all of these events include Tau ZZ*\IniZ µµvv 6 vvµµ 6 eevv 6 vvee 6 6

17 ZZ*\InitZ vv µµ 6 µµ 6 ee 6 ee 6 missing mass mina&m ina direction of missingp volume of jj_n signal _sl _sl _sl _sl _sl missing mass signal _sl _sl _sl _sl _sl mina&m ina direction of missingp ZZ*\IniZ e + e - µ + µ - vv 6 6 vv 6 6 volume of jj_n direction of missingp voloum Max_Min _angle MissingM ass H->bb:6 *->tauv :07 ->µv :5 7 All of these events includes Tau

18 select the most isolated charged particle among the particle flow objects without isolated lepton measure the inter angle between its closest neighbour and itself. the volume of tetrahedron which is made of jets and missing 4 momentum 8

19 Sum up of RA on kinds of final state channel ZZ*\IniZ µ + µ - e + e - vv 5.%.6% vv N/A N/A vv µµ.4% µµ.9% ee 8.6% final state eevv µµvv RA.6% 6.67% ee N/A 9

20 Summery of fs channel Cut-base->TMVA Combine all the sub-channel A valid Tau finder Fast-simulated SM background->full-simulated SM background More variables 0

21 Analysis Final Lepton neutrino Quark BR % 0% 70% ZZ* ll taus vv 4q k 9.4k v+q k 5.9k l+q v l+v l X+tau since we treat Z and Z* as different particles, when ZZ* decay to different kinds of final states, the block spilt into two equal parts.

22 jets versus 4jets jets 4 Jets Force Jets Event into 4 Jets event

23 Force Jets events into 4 Jetsevent y

24 Summery of 4 jets channel RA = 48.5% jets from Z* ruin a lot More powerful tools depending CEPC environment are needed 4

25 BACKUP 5

26 ZZZ*->eevvjj _sl _sl _sl _sl _sl 5 4 _sl _sl _sl _sl _sl 5 4 _sl _sl _sl _sl _sl Visble_Energy RawMass_Jets RawMass_di_Elec 4 _sl _sl _sl _sl _sl 4 _sl _sl _sl _sl _sl 4 _sl _sl _sl _sl _sl npfos diffjets inter_angle_jets 4 _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl MissingMass Visble_Energy Visble_momenntum 6

27 _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl RawMass_Jets di_elec_momentum Leading_ex_lep_En _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl _sl direction if MissingP mina di_elec_recoilmass 7

28 ZZZ*->µµvvjj npfos Visble_Energy RawMass_Jets RawMass_di_muon MissingMass diffjets Visble_Energy RawMass_Jets En_leading extra lepton

29 ZZZ*->vvµµjj 5 4 RMass sig RMass BackGround MissingMass RMass RMass RawMass_di_Jets RawMass_di_muon interangle between leptons and Jets 9

30 ZZZ*->vvjjµµ mina.5 sig mina.5 BackGround RMass 40 0 sig RMass 40 0 BackGround mina mina RMass RMass interangle between leptons and Jets RrecoMass_di_Jets 0

31 ZZZ*->vveejj _4q RMass sig _4q MissingMass RMass mina _4q _4q _4q mina di_muon_recoilmass interangle between leptons and otherpfos _4q _4q _4q di_jet_recoilmass direction of MissingP Visble_Mass

32 Thanks! Yuqian

33 _fusion event_display_back delete some specific variables put a table of sum up, precision,each, plot more readable variable name bigger size page 4 logic number for 4jets events