Probing SUSY Contributions to Muon g-2 at LHC and ILC

Transcription

1 Probing SUSY Contributions to Muon g-2 at LHC and ILC Motoi Endo (Tokyo) Based on papers in collaborations with ME, Hamaguchi, Iwamoto, Yoshinaga ME, Hamaguchi, Kitahara, Yoshinaga ME, Hamaguchi, Iwamoto, Kitahara, Moroi Particle Physics and Cosmology after the Discovery of Higgs Boson, , Tohoku

2 Muon g-2 Search for BSM based on experimental anomalies Magnetic moment g-factor g = 2 at tree level (Dirac equation) g 2 by radiative corrections

3 Status of Muon g-2 Experiment (E821) (63) [10-11 ] QED (α 5, Rb) (0.080) EW (W/Z/HSM, NLO) (1.0) Hadronic [HLMNT] (43) (leading) [DHMZ] (42) had Hadronic (α higher) (0.7) Hadronic (LbL) [RdRV] 105 (26)* [NJN] 116 (39) had > 3σ deviation

4 Status of Muon g-2 Experiment (E821) (63) [10-11 ] QED (α 5, Rb) (0.080) EW (W/Z/HSM, NLO) (1.0) Hadronic [HLMNT] (43) (leading) [DHMZ] (42) had Hadronic (α higher) (0.7) Hadronic (LbL) [RdRV] 105 (26)* [NJN] 116 (39) had > 3σ deviation

5 New Physics Contribution Δa μ gnew 2 (muon mass ~106MeV) 2 16π 2 (new particle mass) 2 Discrepancy (~EW) is explained new gnew W boson coupling μ particle μ mnew W boson mass gnew gnew No such particles have been discovered γ

6 New Physics Contribution Δa μ gnew 2 (muon mass ~106MeV) 2 16π 2 (new particle mass) 2 weak interaction, small mass e.g. heavy photon model (~10-100MeV) strong interaction, large mass Supersymmetry (~100GeV) Today s subject: Test of SUSY solution at colliders

7 Outline Status of muon g-2 - more than 3σ deviation between SM and Exp. - can be a sign of low-scale SUSY Probing SUSY contributions to muon g-2 types of contributions probing the contributions at LHC and ILC Summary

8 Two Types of Contributions chargino-muon sneutrino neutralino-smuon Enhanced by tanβ:

9 Two Types of Contributions chargino-muon sneutrino neutralino-smuon light particles muon sneutrino (smuon) Wino, Higgsino large tanβ light particles L- and R-smuons Bino large smuon LR mixing SUSY solution can be tested, if these particles are discovered

10 Outline Status of muon g-2 - more than 3σ deviation between SM and Exp. - can be a sign of low-scale SUSY Probing SUSY contributions to muon g-2 types of contributions probe: status, prospect - chargino type - neutralino type Summary

11 1. Probing Chargino Contributions light particles muon sneutrino (smuon) Wino, Higgsino [ME, Hamaguchi, Iwamoto, Yoshinaga]

12 Mass Spectrum Chargino contributions are sizable: light: smuon, Wino, Higgsino + Bino (LSP) large tanβ (= 40) * other SUSY particles are heavy (decoupled)

13 Mass Spectrumg- ~ 900 Chargino contributions are sizable: 600 Colored light: smuon, Wino, mass Higgsino >~ Bino 1TeV (LSP) 400 large tanβ (= 40) * other SUSY particles are heavy (decoupled) 100 LSP mass [GeV] g ~ production, CMS Preliminary s = 8 TeV EPSHEP 2013 kinematically forbidden -1 SUS lep (H + H T ) 19.5 fb T SUS lep (α T ) 11.7 fb g ~ q q χ 0 1 Observed Expected gluino mass [GeV]

14 Mass Spectrum No mixing (Xt=0) Chargino contributions are sizable: light: smuon, Wino, Higgsino + Bino (LSP) large tanβ (= 40) * other SUSY particles are heavy (decoupled) ATLAS/CMS Combined(1σ) error: top mass, αs [Feng,Kant,Profumo,Sanford]

15 Mass Spectrum Chargino contributions are sizable: light: smuon, Wino, Higgsino + Bino (LSP) large tanβ (= 40) * other SUSY particles are heavy (decoupled)

16 Mass Spectrum Chargino contributions are sizable: light: smuon, Wino, Higgsino + Bino (LSP) large tanβ (= 40) * other SUSY particles are heavy (decoupled)

17 LHC: Chargino Type Multi-lepton signature: 800 sleptons lighter than Winos Wino three-body decays slepton mass [GeV] g-2 1σ 2σ LHC Multi-lepton ATLAS 3 leptons + MET [ATLAS-CONF-NOTE ] Wino mass [GeV] [Endo,Hamaguchi,Iwamoto,Yoshinaga]

18 LHC: Chargino Type SM-boson signatures: 800 sleptons heavier than Winos currently very weak slepton mass [GeV] g-2 SM-bosons 2σ 1σ LHC H, W, Z ATLAS-CONF , 093 CMS-PAS-SUS Wino mass [GeV] [Endo,Hamaguchi,Iwamoto,Yoshinaga]

19 LHC: Chargino Type Multi-lepton: 800 most sensitive (expect) improved well SM-bosons: Wh: Wino, Higgsino mass ~ GeV at 14TeV, 300fb -1 [Berggren,et.al., ] slepton mass [GeV] g-2 SM-bosons 2σ 1σ Multi-lepton LHC WZ: Wino mass ~ 800GeV (1TeV) for 300(3000)fb -1 [ATLAS-PHYS-PUB ,CMS-NOTE ] Wino mass [GeV] [Endo,Hamaguchi,Iwamoto,Yoshinaga]

20 Outline Status of muon g-2 - more than 3σ deviation between SM and Exp. - can be a sign of low-scale SUSY Probing SUSY contributions to muon g-2 types of contributions probe: status, prospect - chargino type: LHC w/ multi-lepton, SM bosons - neutralino type Summary

21 2. Probing Neutralino Contributions light particles L- and R-smuons Bino large smuon LR mixing [ME, Hamaguchi, Kitahara, Yoshinaga, ME, Hamaguchi, Iwamoto, Kitahara, Moroi]

22 Mass Spectrum Neutralino contributions are sizable: light: left- and right-handed smuons, Bino large LR mixing parameter ( μ tanβ) * other SUSY particles (Winos, Higgsinos) are heavy

23 Mass Spectrum Muon g-2 is explained when smuon mass < 330/460GeV vacuum stability (stau-h) slepton mass degeneracy to avoid FCNC/CP stau searches at LEP, LHC g-2 LHC di-lepton search LHC [ATLAS-CONF ,CMS-PAS-SUS ] [Endo,Hamaguchi,Kitahara,Yoshinaga]

24 Neutralino contribution at ILC ILC can probe neutralino contribution to muon g-2 lightest smuon is within kinematical reach of ILC cross section >~ 1fb g-2 1σ 2σ It is possible to reconstruct at ILC under some conditions [Endo,Hamaguchi,Kitahara,Yoshinaga]

25 Reconstructing 2. Probing Neutralino Contributions light particles L- and R-smuons Bino large smuon LR mixing [ ME, Hamaguchi, Iwamoto, Kitahara, Moroi]

26 Reconstruction at ILC Muon g-2 parameters:

27 Reconstruction at ILC Muon g-2 parameters: Neutralino contribution is reconstructed * Winos and Higgsinos are decoupled

28 Setup Sample point Parameters m l1 m l2 m τ1 m τ2 m χ 0 1 sin θ µ sin θ τ a (ILC) µ Values others are decoupled All of selectrons, smuons and staus are within kinematical reach of ILC at Close to SPS1a( ): [left-handed sleptons are lighter] - avoid LHC/LEP limits - previous studies of ILC can be applied

29 Overview precise by studying endpoints or by threshold scans too small to measure directly stau productions [most uncertain, strongly depend on model point] theoretically uncertain because of radiative corr. and mixing involved in t-channel neutralino exchanges of the processes

30 Mass Measurement Smuon and neutralino masses are measured precisely by studying endpoint or by threshold scans Studies at SPS1a( ) with polarized beams, ILC can provide ) -1 Yield (500 fb Standard Model Background ( 1) SUSY background( 10) e e e + e - µ µ - µ L L µµ µµ 0 1 µ ( 10) ( 100) or better µ energy [GeV] [Berggren,d Ascenzo,Schade,Stempel]

31 Smuon LR Mixing LR mixing is measured by the relation: Measurement of stau mass: endpoint of tau (-jet) energy jets/0.7 Gev Based on detailed study at [GeV] E jet [Bechtle,Berggren,List,Schade,Stempel]

32 Smuon LR Mixing contd. Measurement of stau mixing angle: cross section of stau Cross section depends on the angle via s-channel Z exchange e + γ, Z µ + e µ after some discussions at

33 Smuon LR Mixing contd. LR mixing is measured by the relation: From stau productions, [500fb -1 ] Note that is very sensitive to mixing, though there is no study

34 Gaugino Couplings Couplings of Neutralino-Slepton-Lepton equal to gauge coupling constant at LO deviate due to radiative corrections as well as mixing with (unobserved) Winos and Higgsinos left right 1-10% correction The couplings should be determined directly at ILC

35 Gaugino Couplings Selectron productions involve t-channel neutralino exchanges e + e + e χ 0 j e contamination of (unobserved) Winos and Higgsinos is less than 0.4% E.g. exp: measurement of cross section, th: Winos, Higgsinos

36 Reconstruction at ILC Neutralino contribution to muon g-2 is reconstructed by measuring all the sleptons at the sample point with + correction from Winos, Higgsinos is 4% (1%) for >1TeV (1.5TeV) X δx δ X a (ILC) µ Process m 2 µlr 12 % 13 % e + e τ + τ (cross section, endpoint) (sin 2θ τ ) (9%) e + e τ 1 + τ 1 (cross section) (m τ2 ) (3%) e + e τ 2 + τ 2 (endpoint) m µ1, m µ2 200 MeV 0.3% e + e µ + µ (endpoint) m χ MeV < 0.1% e + e µ + µ /ẽ + ẽ (endpoint) g (eff) 1,L afew+1% afew+1% e + e ẽ + Lẽ R (cross section) g (eff) 1,R 1% 0.9% e + e ẽ + Rẽ R (cross section)

37 Extra Contribution to Muon g-2 aμ(susy; total) - aμ(susy; ILC) Null signal of Winos/Higgsinos reduces theoretical uncertainties

38 Summary Muon g-2 has >3σ deviation between SM prediction and experimental value. SUSY is a good candidate to explain the anomaly. We discussed how to probe SUSY contributions. chargino contribution can be probed at LHC - EWKino search: multi-lepton, SM bosons neutralino contribution can be probed at ILC - sleptons are within kinematical reach - It is possible to reconstruct the contribution, if all the sleptons (selectrons, smuons and staus) are measured