Magnetic moment g 2µ and new physics

Transcription

1 Dominik Stöckinger, TU Dresden Heidelberg, November 2012

2 Muon magnetic moment H magnetic 2 1 a µe 2m B S e circular motion: c m B spin precession: s 2 1 a µe 2m B

3 Muon magnetic moment H magnetic 2 1 a µe 2m B S Quantum field theory: a 2m q a u pµ u p¼µ F1 i Operator: m L q R

4 Outline 1 a SM status? a 2 Impact on New Physics in general 3 SUSY Can explain the deviation a constraints LHC vs Subleading contributions 4 Alternatives to SUSY 5 Conclusions

5 Outline 1 a SM status? a 2 Impact on New Physics in general 3 SUSY Can explain the deviation a constraints LHC vs Subleading contributions 4 Alternatives to SUSY 5 Conclusions a SM status?

6 Three Fermions g Electron: g µ Muon: Proton: g µ g 2 1 a µ a SM status?

7 Three Fermions 3µ Electron: g µ Muon: g Proton: g µ g 2 1 a µ a SM status?

8 «2 (Pre)history 49 Schwinger: QED 1L: 57 Garwin et al: g 2µMuon=Dirac particle! a SM status?

9 «2 (Pre)history 49 Schwinger: QED 1L: 57 Garwin et al: g 2µMuon=Dirac particle! CERN exp.: hadronic cont. needed, confirmed! a SM status?

10 «2 (Pre)history 49 Schwinger: QED 1L: 57 Garwin et al: g 2µMuon=Dirac particle! CERN exp.: hadronic cont. needed, confirmed! 83 12: QED 4L,5L (numerically) [Kinoshita] Had light-by-light: difficult! e.w. contributions: 2L full a SM status?

11 «2 (Pre)history 49 Schwinger: QED 1L: 57 Garwin et al: g 2µMuon=Dirac particle! CERN exp.: hadronic cont. needed, confirmed! 83 12: QED 4L,5L (numerically) [Kinoshita] Had light-by-light: difficult! e.w. contributions: 2L full BNL exp.: weak cont. needed, not confirmed! a SM status?

12 SM prediction a SM [Miller, de Rafael, Roberts, DS 12] QED: (0.0) had Had vp: (4.2) had W Had lbl: 10.5 (2.6) G Weak: 15.3 (0.1) a SM status?

13 SM prediction a SM [Miller, de Rafael, Roberts, DS 12] QED: (0.0) had Had vp: QED: complete 5-loop result [Aoyama, Hayakawa, Kinoshita, Nio 12] QED uncertainty dominated by«had W Had lbl: G Weak: a SM status?

14 SM prediction a SM [Miller, de Rafael, Roberts, DS 12] Hadronic vacuum polarization: QED: had Had vp: had W Had lbl: G Weak: (4.2) e e hadrons depends on exp data (e e, also -decays) ÁSND, CMDII (energy scan) ÁKLOE08, KLOE10, Babar (rad return) convergence of theoretical determinations most recent: EFT induced interpolation slightly lower result [Benayoun, David, DelBuono, Jegerlehner 12] a SM status?

15 SM prediction a SM [Miller, de Rafael, Roberts, DS 12] Hadronic vacuum polarization: QED: had Had vp: had W Had lbl: G Weak: (4.2) [Benayoun, David, DelBuono, Jegerlehner 12] τ + PDG Prediction (A+B+C)(PDG) [38.10 ± 6.80] [4.1 σ] scan all ISR τ data DHMZ10 (e + e + τ) [19.5 ± 5.4] [2.4 σ] JS11 (e + e + τ) [29.2 ± 6.0] [3.4 σ] Full BHLS (e + e + τ) [32.54 ± 4.98] [4.1 σ] scan KLOE10 τ data BHLS::B (e + e + τ) [39.91 ± 5.21] [4.9 σ] BHLS::A (e + e + τ) [38.44 ± 5.18] [4.7 σ] scan τ data DHea09 (e + e ) [30.1 ± 5.8] [3.5 σ] Full BHLS(e + e + τ) [35.43 ± 5.23] [4.3 σ] scan τ data BHLS::B (e + e + τ) [36.88 ± 5.28] [4.5 σ] BHLS::A (e + e + τ) [35.43 ± 5.23] [4.3 σ] scan all ISR & excl. τ data DHMZ10 (e + e ) [28.7 ± 4.9] [3.6 σ] HLMNT11(e + e ) [26.1 ± 4.9] [3.3 σ] Full BHLS (e + e ) [33.62 ± 5.06] [4.2 σ] scan KLOE10 & excl. τ BHLS::B (e + e ) [41.91 ± 5.45] [5.0 σ] BHLS::A (e + e ) [40.31 ± 5.42] [4.9 σ] experiment 6.3] BNL-E821(avrg) [0 ± (a exp µ a th µ ) 1010 a SM status?

16 SM prediction a SM [Miller, de Rafael, Roberts, DS 12] Hadronic light-by-light: QED: had Had vp: had W Had lbl: G Weak: 10.5 (2.6) not from first principles models [Bijnens, Prades 07] [Melnikov, Vainshtein 03] [Jegerlehner 08] [Jegerlehner, Nyffeler 09] [Prades, Vainshtein, de Rafael 08] Glasgow consensus: combine methods, inflate errors Promising new approaches: lattice, Dyson-Schwinger a SM status?

17 SM prediction a SM [Miller, de Rafael, Roberts, DS 12] QED: had Had vp: Weak: 2-loop result (M H ½) [Czarnecki, Krause, Marciano 95] with full Higgs mass dependence [Heinemeyer, DS, Weiglein 04][Czarnecki, Gribouk 05] µcurrent M H constraints fix a weak had W Had lbl: G Weak: 15.3 (0.1) a SM status?

18 Current status: SM prediction HMNT (06) JN (09) Davier et al, τ (10) Davier et al, e + e (10) JS (11) HLMNT (10) HLMNT (11) BNL experiment BNL (new from shift in λ) a µ largest uncertainty from e e data smaller from lbl both will improve in future Full SM: a JN09: HLMNT09: µ 4 0 µ µ 3 2 µ Detal09: µ 3 2 µ JS11: HLMNT11: µ 3 3 µ µ 3 3 µ BDDJ11: MdRRS12: µ 3 6 µ µ 4 1 µ BDDJ12: µ 4 7 µ Exp: BNL06: µ a SM status?

19 Muon g 2 experiment at Brookhaven a 11 exp µstat 3 3µsyst 6 3µtotµ 10 (error statistics dominated! agreement, ) a SM status?

20 Theory confronts experiment CERN measurement: hadronic cont. needed, confirmed! BNL measurement: weak cont. needed, not confirmed! Legacy of the CERN experiment a SM status?

21 Theory confronts experiment CERN measurement: hadronic cont. needed, confirmed! BNL measurement: weak cont. needed, not confirmed! Legacy of the BNL experiment a SM status?

22 Theory confronts experiment CERN measurement: hadronic cont. needed, confirmed! BNL measurement: weak cont. needed, not confirmed! Legacy of the BNL experiment a SM status?

23 Theory confronts experiment CERN measurement: hadronic cont. needed, confirmed! BNL measurement: weak cont. needed, not confirmed! Legacy of the BNL experiment a SM status?

24 Discrepancy SM prediction too low by 30 8µ Note: discrepancy twice as large as a SM weak but we expect: a NP a SM weak M W M NP 2 couplings a SM status?

25 Future experiments at Fermilab and JParc (N. Saito) a SM status?

26 The Opportunity µ a SM status?

27 The Opportunity a SM status?

28 Photo from 29/09/12 Official CD-0 approval September 2012 a SM status?

29 Advantages of Fermilab decay length 900m vs 88m 6 12 times more stored muons per initial proton 4 times fill frequency 20 times reduced hadronic-induced background at injection a SM status?

30 Complementary experiment at JParc (N. Saito) a SM status?

31 Complementary experiment at JParc (N. Saito) a SM status?

32 a Goal of both new g 2µexperiments a exp SM Exp 3 4 Th µ 10 Data in 4 5 years 10 Useful complement of LHC (and flavour physics experiments), independent of final value [Hertzog, Miller, de Rafael, Roberts, DS 07] a SM status?

33 Outline 1 a SM status? a 2 Impact on New Physics in general 3 SUSY Can explain the deviation a constraints LHC vs Subleading contributions 4 Alternatives to SUSY 5 Conclusions Impact on New Physics in general

34 Why is a special? R L b s B e CP- and Flavour-conserving, chirality-flipping, loop-induced compare: EDMs, EWPO Impact on New Physics in general

35 Why is a special? R L b s B e CP- and Flavour-conserving, chirality-flipping, loop-induced compare: EDMs, EWPO Note relation to m R L Impact on New Physics in general

36 C Æm N P µ Æa N P µ Ç Cµ m a Very different contributions to generally: classify new physics: C very model-dependent M 2 Impact on New Physics in general

37 C Æm N P µ Æa N P µ Ç Cµ m a Very different contributions to Ç 1µ generally: classify new physics: C very model-dependent Ç «4 µ Ç «4 µ Z¼, M 2 W¼, UED, Littlest Higgs (LHT)... Impact on New Physics in general

38 C Æm N P µ Æa N P µ Ç Cµ m a Very different contributions to generally: Ç 1µ M 2 classify new physics: C very model-dependent Ç «4 µ supersymmetry (tan ), unparticles [Cheung, Keung, Yuan 07] Ç «4 µextra dim. (ADD/RS) (n c )... [Davioudasl, Hewett, Rizzo 00] [Graesser, 00][Park et al 01][Kim et al 01] Z¼, W¼, UED, Littlest Higgs (LHT)... Impact on New Physics in general

39 C Æm N P µ Æa N P µ Ç Cµ m a Very different contributions to generally: Ç 1µ M 2 classify new physics: C very model-dependent radiative muon mass generation... Ç «4 µ [Czarnecki,Marciano 01] [Crivellin, Girrbach, Nierste 11][Dobrescu, Fox 10] supersymmetry (tan ), unparticles [Cheung, Keung, Yuan 07] Ç «4 µextra dim. (ADD/RS) (n c )... [Davioudasl, Hewett, Rizzo 00] [Graesser, 00][Park et al 01][Kim et al 01] Z¼, W¼, UED, Littlest Higgs (LHT)... Impact on New Physics in general

40 C Æm N P µ Æa N P µ Ç Cµ m a Very different contributions to generally: Ç 1µ classify new physics: C very model-dependent Very useful constraints on new physics radiative M 2 muon mass generation... Ç «4 µ [Czarnecki,Marciano 01] [Crivellin, Girrbach, Nierste 11][Dobrescu, Fox 10] supersymmetry (tan ), unparticles [Cheung, Keung, Yuan 07] Ç «4 µextra dim. (ADD/RS) (n c )... [Davioudasl, Hewett, Rizzo 00] [Graesser, 00][Park et al 01][Kim et al 01] Z¼, W¼, UED, Littlest Higgs (LHT)... Impact on New Physics in general

41 Outline 1 a SM status? a 2 Impact on New Physics in general 3 SUSY Can explain the deviation a constraints LHC vs Subleading contributions 4 Alternatives to SUSY 5 Conclusions SUSY

42 SUSY and the MSSM MSSM: free parameters: p masses and mixings, and tan SUSY

43 W g 2 in the MSSM: chirality flips,, and H u Each diagram H u», some u vev H d R Note tan H d, H H u H d transition Hence, some u m tan 2 terms» H a SUSY»tan sign µm MSUSY 2 potential enhancement»tan 1 50 (and»sign( )) W L SUSY

44 g 2 in the MSSM numerically a SUSY tan sign µ 100GeV M SUSY 2 SUSY could be the origin of the observed 30 8µ deviation! positive, large tan /small M SUSY preferred however, beware of the fine print... Precise analysis justified! SUSY

45 a central complement for SUSY parameter analyses SPS benchmark points [v.weitershausen,schäfer, Stöckinger-Kim,DS 10] LHC Inverse Problem (300fb 1 ) can t be distinguished at LHC [Sfitter: Adam, Kneur, Lafaye, Plehn, Rauch, Zerwas 10] a sharply distinguishes SUSY models helps measure parameters [Hertzog, Miller, de Rafael, Roberts, DS 07] SUSY

46 a central complement for SUSY parameter analyses SPS benchmark points [v.weitershausen,schäfer, Stöckinger-Kim,DS 10] LHC Inverse Problem (300fb 1 ) can t be distinguished at LHC [Sfitter: Adam, Kneur, Lafaye, Plehn, Rauch, Zerwas 10] [Hertzog, Miller, de Rafael, Roberts, DS 07] vision: test universality of tan, like for cos W M W MZ t µa t µlhc masses t µh t µb? in the SM: SUSY

47 The tension is increasing LHC: m q g 1TeV a m 700GeV m h 126 GeV(?) m t 1TeV finetuning m t small also: dark matter, b-physics, FCNC/CP-constraints SUSY

48 Constrained models I a vs LHC-bounds on squarks/gluinos vs potential m h -measurement CMSSM, LHC, m =126 GeV h CMSSM: link m q m m h incompatible SM a µ - a µ (2.9 ± 0.8 ± 0.2)E-9 0.3E-9 BR(b sγ) (3.55 ± 0.26 ± 0.23)E E-4 BR(B τν) (1.67 ± 0.39)E E-4 BR(B µ + µ - ) s <(4.50 ± 0.30)E E-9-1 m s (ps ) ± 0.12 ± l sin θ eff ± m W (GeV) ± ± m h (GeV) ± 2.0 ± LHC 2 Ω CDM h ± ± SI σ (pb) 2.44E Meas.-Fit / σ NUHM1, LHC, m =126 GeV h NUHM1: mh soft independent marginally compatible finetuning? SM a µ - a µ (2.9 ± 0.8 ± 0.2)E-9 1.8E-9 BR(b sγ) (3.55 ± 0.26 ± 0.23)E E-4 BR(B τν) (1.67 ± 0.39)E E-4 - BR(B µ + µ ) s <(4.50 ± 0.30)E E-9-1 m s (ps ) ± 0.12 ± l sin θ eff ± m W (GeV) ± ± m h (GeV) ± 2.0 ± LHC 2 Ω CDM h ± ± σsi (pb) 1.81E Meas.-Fit / σ SUSY

49 Constrained models II m q increase m h, lower Natural SUSY [Barger, Huang, Ishida, Keung 12]... 1st, 2nd generation very heavy, light t FCNC, finetuning ok a 0, would need m m q Gauge-mediated SUSY breaking (FCNC ok) + extra matter reconcile a, m h a, LHC-bounds [Endo, Hamaguchi, Iwamoto, Yokozaki 11]... Compressed SUSY [Martin, LeCompte 11] hidden at LHC for m q g 600GeV compatible with Still tension/models might be be ruled out soon! SUSY

50 Alternative: radiative muon mass in SUSY tan ½ v d 0, generate m via A¼ L RH m v tree d u [Borzumati et al 99][Crivellin et al 11] generate m via coupling to v u [Dobrescu, Fox 10][Altmannshofer, Straub 10] SUSY

51 »tan m 1-Loop 2-Loop (SUSY 1L) 2-Loop (SM 1L) e.g.»log M SUSY e.g.»tan m t t H Status of SUSY prediction 0 0 f f [Fayet 80],... [Kosower et al 83],[Yuan et al 84],... [Lopez et al 94],[Moroi 96] [Degrassi,Giudice 98] [Marchetti, Mertens, Nierste, DS 08] [Schäfer, Stöckinger-Kim, v. Weitershausen, DS 10] [Chen,Geng 01][Arhib,Baek 02] [Heinemeyer,DS,Weiglein 03] [Heinemeyer,DS,Weiglein 04] complete photonic complete tan µ2 aim: full calculation (65000 diagrams) SUSY

52 Physics of subleading contributions (examples) L» for ½ 1-loop bino B B L R R L H 1 1-loop R H 2 B R»other sign! B R large -parameter Use if M 2 0, light R SUSY

53 Physics of subleading contributions (examples) L» for ½ 1-loop bino B B L R R L H 1 1-loop R H 2 B R»other sign! B R large -parameter radiative muon mass, 0 Use if M 2 0, light R SUSY

54 W tan 1 tan µ 2 W 2-loop H 2 H 1 R 1 L 2-loop t t H m t M m t H log MSUSY m µ Photonic 2-loop Important for drawing precise conclusions from confronting SUSY-prediction with a Exp SM SUSY

55 W tan 1 tan µ 2 W 2-loop H 2 H 1 R 1 Allows limit tan ½! Wrong sign! L 2-loop t t H m t M m t Dominant for heavy smuons! H log MSUSY m µ Photonic 2-loop Important for drawing precise conclusions from confronting SUSY-prediction with a Exp SM SUSY

56 Outline 1 a SM status? a 2 Impact on New Physics in general 3 SUSY Can explain the deviation a constraints LHC vs Subleading contributions 4 Alternatives to SUSY 5 Conclusions Alternatives to SUSY

57 EWSB Models Large a possible? Randall Sundrum Littlest Higgs + T-Parity ( Bosonic SUSY ) 2-Higgs doublet model + 4th generation Alternatives to SUSY

58 EWSB Models Large a possible? Randall Sundrum Littlest Higgs + T-Parity ( Bosonic SUSY ) 2-Higgs doublet model + 4th generation Randall Sundrum KK-gravitons large [Kim, Kim, Song 01] However, challenged by electroweak precision data [Hewett et al 00] and unitarity [Kim,Kim,Song 01] non-graviton contributions small [Beneke, Dey, Rohrwild 12] Alternatives to SUSY

59 EWSB Models Large a possible? Randall Sundrum Littlest Higgs + T-Parity ( Bosonic SUSY ) 2-Higgs doublet model + 4th generation Littlest Higgs + T-Parity [Cheng, Low 03] [Hubisz, Meade, Noble, Perelstein 06] Tiny a from Z H, W H contributions [Blanke et al 07] Alternatives to SUSY

60 EWSB Models 5e-09 4e-09 Large a possible? Randall Sundrum Littlest Higgs + T-Parity ( Bosonic SUSY ) 2-Higgs doublet model + 4th generation a µ 3e-09 2e-09 M H + = 500 GeV m ν =100 GeV (black) 1e-09 =200 GeV (red) =400 GeV (blue) δ Σ2.δ U2 2-Higgs doublet model + 4th generation [Bar-Shalom, Nandi, Soni 11] Large contributions from ¼ H possible in agreement with LFV, FCNC constraints Alternatives to SUSY

61 Other types of new physics What if the LHC does not find new physics? Hide new particles at colliders large L L a possible Dark force? [Pospelov, Ritz... ] 3 very light, weakly interacting 10 C»10 8, M 1GeV κ Excluded by electron g-2 vs α Light Z¼ from gauged 5 10 [Ma, Roy, Roy 02][Heeck, Rodejohann 11] muon g-2 <2σ Excluded by muon g-2 flavour-dependent couplings, hidden at LEP C C SM weak, M Z¼ M Z 6 10 [Pospelov 08] 10 MeV 100 MeV 500 MeV m V Alternatives to SUSY

62 Outline 1 a SM status? a 2 Impact on New Physics in general 3 SUSY Can explain the deviation a constraints LHC vs Subleading contributions 4 Alternatives to SUSY 5 Conclusions Conclusions

63 Currently a Exp a SM 30 8µ reliable, tantalizing New measurements within next 5 years very promising! Conclusions N P a very model-dependent, typicallyç 1 50µ Áconstraints, model discriminator, unique properties Ábreak degeneracies measure central parameters complementary to LHC If large a -deviation is real: tension rising between LHC-bounds, a, finetuning, Higgs mass; difficult to find alternatives to SUSY Promising future!! Conclusions