Charged Lepton Flavor Violation (CLFV), Anomalous Magnetic Moment (g-2) and Electric Dipole Moment (EDM) 2nd International Conference on Charged Lepton Flavor Violation @ Charlottesville, Virginia, USA. June 20-22, 2016 Kazuhiro Tobe (Nagoya University)
Plan of my talk Is CLFV interesting? g-2, and EDM effective operator analysis CLFV, muon g-2 and EDM in a general two Higgs doublet model (as a concrete example) Refs: JHEP 1505, 028 (2015), arXiv: 1511.08880 Omura, Senaha, Tobe ‣ Introduction ‣ Model independent study for CLFV, ‣ ‣ Summary
Introduction “Flavor” in the standard model (SM) ★Fermion masses and mixings are free parameters ★No principle nor theory for flavor If there is any principle or theory for flavor, it must be physics beyond the SM. flavor is still a mystery in the SM
“Flavor” in the physics beyond the SM ★ there is additional origin of flavor violations flavor violating squark/lepton masses in SUSY models e.g. extra Yukawa interactions in two Higgs doublet model ★No principle nor theory for flavor Typically it is difficult to make any definite predictions in flavor violating processes “Flavor” is difficult problem, but theoretical and experimental studies for flavor will be important to make a deeper understanding of flavor.
Why is Lepton Flavor Violation (LFV) interesting? and large flavor mixings •dimension 5 operator for neutrino masses very high scale! ★ neutrino oscillation results suggest tiny neutrino masses • each lepton flavor number is violated L d =5 = 1 Λ ( LH ) c ( LH ) m ν = h H i 2 Λ Λ ∼ 10 15 GeV q ∆ m 2 for m ν = atm .
In the standard model with tiny neutrino masses Charged lepton flavor violation, μ→eγ, is induced, but very tiny γ W − W − µ ν i e m ν i m ν i BR( µ → e γ ) ∼ m 4 < 10 − 50 ν m 4 W
Is Charged LFV (CLFV) not interesting? ★Various motivated new physics models •WIMP dark matter Supersymmetry, Little Higgs, extra dimension, etc New physics scale ~ TeV New physics scale ~ TeV New origin of CP violation e.g. electroweak baryogenesis ~ TeV • Solutions to hierarchy problem • Baryon asymmetry in the universe
★Hints from experimental data related to lepton flavor?? reported by CMS (2.4σ excess) • Lepton flavor violating Higgs boson decay h→μτ
Talk by P. Onyisi @FPCP 2015 CMS best fit: 2.4σ excess CMS: arXiv: 1502.07400 CMS collaboration has reported an excess in h → µ τ BR( h → µ τ ) = (0 . 84 +0 . 39 − 0 . 37 )%
→ μ → τ μ τ ATLAS Hint for new physics! ATLAS: arXiv: 1508.03372 In Moriond EW 2016 2.4σ excess consistent with CMS ATLAS: arXiv: 1508.03372 CMS best fit: → τ μ σ → τ BR( h → µ τ ) = (0 . 77 ± 0 . 62)% → → τ τ τ τ H → τ μ : τ τ μ μ ATLAS: BR = 0.53 ± 0.51% < 1.43% (95% CL) CMS: → τ BR( h → µ τ ) = (0 . 84 +0 . 39 − 0 . 37 )% μ τ
Need more data No excess is observed CMS PAS HIG-16-005 New 13 TeV result from CMS -1 CMS Preliminary 2.3 fb (13 TeV) , 0 Jets µ τ had 4.17% (exp.) Observed 4.24% (obs.) Expected , 1 Jet µ τ had 1 std deviation ± 4.89% (exp.) 6.35% (obs.) 2 std deviation ± , 2 Jets µ τ had 6.41% (exp.) 7.71% (obs.) 8 TeV [Phys. Lett. B 749 (2015) 337]: , 0 Jets µ τ e Observed 2.24% (exp.) 1.33% (obs.) Expected , 1 Jet µ τ e 4.36% (exp.) 3.04% (obs.) , 2 Jets µ τ e 7.31% (exp.) 8.99% (obs.) H → µ τ 1.62% (exp.) 1.20% (obs.) 0 5 10 15 20 25 95% CL Limit on Br(H ), % → µ τ Figure 4: Observed and expected 95% CL upper limits on the B ( H → µ τ ) for each individual category and combined. The solid red and dashed black vertical lines correspond, respectively, to the observed and expected 95% CL upper limits obtained at √ s = 8 TeV [23].
reported by CMS (2.4σ excess) ★Hints from experimental data related to lepton flavor?? • Lepton flavor violating Higgs boson decay h→μτ • Lepton universality in B + → K + l + l − ( l = e, µ )
Lepton universality ~ gauge interactions ~ hadronic uncertainties cancel in the ratio u u b s W l − Z/ γ l + R K = BR( B + → K + µ + µ − ) BR( B + → K + e + e − )
Talk by Johannes Albrecht @ Moriond 2016 LHCb measures with 3fb -1 R K = BR ( B + → K + µ + µ − ) BR ( B + → K + e + e − ) = 0.745 + 0.090 − 0.074 ( stat ) ± 0.036( syst ) (SM: R k =1.00, consistent at 2.6 σ ) LHCb BaBar Belle 2 K R LHCb 1.5 1 SM , q 0.5 LHCb [PRL113 (2014) 151601 ] ! BaBar [PRD 86 (2012) 032012] ! Belle [PRL 103 (2009) 171801] 0 0 5 10 15 20 2 q 2 [GeV / c 4 ] 13. March 2016 Johannes Albrecht 17/19
★Hints from experimental data related to lepton flavor?? reported by CMS (2.4σ excess) • Lepton flavor violating Higgs boson decay h→μτ • Lepton universality in B + → K + l + l − ( l = e, µ ) B 0 → D ( ∗ )+ l − ¯ ν • Lepton universality in
Lepton universality hadronic uncertainties cancel in the ratio q q b c l − W ¯ ν R D ( ∗ ) = BR( B 0 → D ( ∗ )+ τ − ¯ ν ) BR( B 0 → D ( ∗ )+ l − ¯ ν )
Talk by Johannes Albrecht @ Moriond 2016 0.5 R(D*) 2 BaBar, PRL109,101802(2012) = 1.0 ∆ χ R D * = BR ( B 0 → D * + τ − ν ) Belle, arXiv:1507.03233 0.45 LHCb, arXiv:1506.08614 Average BR ( B 0 → D * + µ − ν ) 0.4 0.35 Belle LHCb 0.3 R ( D ) = 0.375 ± 0.064 ± 0.026 * ) = 0.293 ± 0.038 ± 0.015 R ( D ∗ ) = 0 . 336 ± 0 . 027 ± 0 . 030 R ( D HFAG 0.25 Prel. EPS2015 SM prediction 2 P( ) = 55% χ LHCb 0.2 Combination is 3.9 휎 from the SM expectation: 0.2 0.3 0.4 0.5 0.6 R ( D * ) = 0.336 ± 0.027 ± 0.030 R(D) PRL 115(2015)111803 Combination is 3.9 휎 from the SM expectation: • , R ( D ) = 0 . 297 ± 0 . 017 R ( D ∗ ) = 0 . 252 ± 0 . 003 [Kamenik et al. Phys. Rev. D78 014003 (2008), S. Jajfer et al. Phys. Rev. D85 094025 (2012)]
Comparison with other measurements BELLE Preliminary Central value close to Belle hadronic tag result. Precision improvement over Belle hadronic tag and LHCb results. B → D ( ∗ ) τν τ at Belle P. Goldenzweig 7.2.2016 14 / 19
reported by CMS (2.4σ excess) ★Hints from experimental data related to lepton flavor?? • Lepton flavor violating Higgs boson decay h→μτ • Lepton universality in B + → K + l + l − ( l = e, µ ) B 0 → D ( ∗ )+ l − ¯ ν • Lepton universality in • muon anomalous magnetic moment (muon g-2)
15.4 (0.1): Higgs mass fixed (Grendiger et al ’13) Status of muon g-2 .895 (0.008): 5-loop calculation (Aoyama et al ’12) − QED contribution 11 658 471.808 (0.015) Kinoshita & Nio, Aoyama et al EW contribution 15.4 (0.2) Czarnecki et al Hadronic contributions LO hadronic 694.9 (4.3) HLMNT11 NLO hadronic − 9.8 (0.1) HLMNT11 light-by-light 10.5 (2.6) Prades, de Rafael & Vainshtein Theory TOTAL 11 659 182.8 (4.9) Experiment 11 659 208.9 (6.3) world avg Exp − Theory 26.1 (8.0) 3.3 σ discrepancy (in units of 10 − 10 . Numbers taken from HLMNT11, arXiv:1105.3149) n.b.: hadronic contributions: . . LO NLO l-by-l γ had. µ µ µ had. had. . . D. Nomura (YITP) Indirect searches for new physics Nov. 28, 2013 61 / 86
possibly an evidence of new physics muon g-2 anomaly 3-4σ deviation (~0.54 ppm) DHMZ12 JN09 JS11 BDDJ12 THLMN10 HLMNT11 and the SM prediction Difference between the experimental value a Exp [10 − 10 ] δ a µ = a Exp − a SM [10 − 10 ] µ µ µ 26 . 1 ± 8 . 0 (3 . 3 σ ) 31 . 6 ± 7 . 9 (4 . 0 σ ) 11659208 . 9 ± 6 . 3 33 . 5 ± 8 . 2 (4 . 1 σ ) 28 . 3 ± 8 . 7 (3 . 3 σ ) 29 . 0 ± 9 . 0 (3 . 2 σ ) 28 . 7 ± 8 . 0 (3 . 6 σ )
is comparable to the electroweak contribution If this anomaly is due to new physics, ..... The size of anomaly we expect new particles with EW scale mass strong constraints from EW precision data good target at near future experiments We may be able to discover the new physics before new experiment or/and new (improved) calculation for muon g-2. So, we should study it NOW! δ a µ = (26 . 1 ± 8 . 0) × 10 − 10 a EW = (15 . 4 ± 0 . 1) × 10 − 10 µ
these are not conclusive yet, reported by CMS (2.4σ excess) some of them may be hints for new physics and CLFV weak~TeV scale new physics ★Hints from experimental data related to lepton flavor?? • Lepton flavor violating Higgs boson decay h→μτ • Lepton universality in B + → K + l + l − ( l = e, µ ) B 0 → D ( ∗ )+ l − ¯ ν • Lepton universality in • muon anomalous magnetic moment (muon g-2) • (750 GeV resonance in diphoton mode?? and more )
e.g. Kobayashi-Maskawa Motivated from the observation of CP violation in Kaon system Three generations in the standard model Good experimental data lead us to the right answer! Learn from the history………
these are not conclusive yet, reported by CMS (2.4σ excess) some of them may be hints for new physics weak~TeV scale new physics Interplay between LHC and flavor physics will be important ★Hints from experimental data related to lepton flavor?? • Lepton flavor violating Higgs boson decay h→μτ • Lepton universality in B + → K + l + l − ( l = e, µ ) B 0 → D ( ∗ )+ l − ¯ ν • Lepton universality in • muon anomalous magnetic moment (muon g-2) • (750 GeV resonance in diphoton mode?? and more)
If we have a new physics … new physics (~TeV scale) LFV + neutrino oscillation (+extra source of LFV) Is CLFV interesting?
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