1 / 20

Implications of Br ( m  e g ) and D a m on Muonic Lepton Flavor Violating Processes

Implications of Br ( m  e g ) and D a m on Muonic Lepton Flavor Violating Processes. Chun-Khiang Chua Chung Yuan Christian University. Motivation. Charged lepton flavor violation decays are prohibited in the SM MEG set a tight bound on Br ( m  e g )

jerrod
Télécharger la présentation

Implications of Br ( m  e g ) and D a m on Muonic Lepton Flavor Violating Processes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Implications of Br(meg) and Damon Muonic Lepton Flavor Violating Processes Chun-Khiang Chua Chung Yuan Christian University

  2. Motivation • Charged lepton flavor violation decays are prohibited in the SM • MEG set a tight bound on Br(meg) • Muon g-2 remains an unsolved puzzle (3.xs) (since 2001) • Bounds on meg,3e, muon to electron conversions (m N e N) are constantly improved (1-6 order of magnitude improvements are expected in future)

  3. Current limits and future sensitivities • “Ratios of current bounds” ~ O(1). • Sensitivities will be improved by 1-6 orders of magnitudes in future

  4. We consider… • Muon g-2 and LFV generated by f-yone-loop dig.s: • Use a bottom up approach: data  couplings, masses • Study the correlations among these processes

  5. Investigate Two Cases: • Case I: Cancellations among diagrams are not effective (~order of magnitudes) • Case II: Have some built-in cancellations, e.g. SGIM.

  6. Investigate Two Cases: • Case I: Cancellations among diagrams are not effective (~order of magnitudes) • Case II: Have some built-in cancellations, e.g. SGIM.

  7. Muon g-2 (case I) • gR(L): couplings of mR(L)-y-f int. • gRgR(gLgL) term: • From g2<4p and my,f >100GeV: my,f<300(200)GeV (tight) • g~e: my,f=10-30GeV (disfavored) • gRgL term: (chiral enh.) • From g2<4p and my,f >100GeV: mf<100TeV, my<3000TeV • g~e: my~ 20 TeV • More sensitive than the RR case 10-4 10-5

  8. m LFV (penguins) (case I) 10-8 10-9 Sensitive in RL is more than 3 orders of mag. better than the RR case megbound is most severe

  9. m LFV (penguins) (case I) Exp. bound ratios ~ O(1) megconstrains other processes

  10. m LFV (Z-penguins) (case I) • Consider vanishing mixing limit of f weak eigenstate. • For my=(>)O(100)GeV, Z-peng. has similar (better) sensitivity as the RR g-peng. • Z-peng is less sensitive than the RL g-peng. unless my is as heavy as O(100) TeV • Br(Zme)<10-13~15 [BrUL(Zme)~10-6] 10-4 10-8 Z-peg. g-peg.

  11. m LFV (boxes) (case I) • Dirac and Majoranacases have different sensitivities • me g+perturbativity (+Dam+edm) exclude some (most) parameter space.

  12. Comparing Br(meg) and Dam • The ratio is smaller than any known coupling ratio among 1st and 2nd generations.

  13. Investigate Two Cases: • Case I: Cancellations among diagrams are not effective (~order of magnitudes) • Case II: Have some built-in cancellations, e.g. SGIM.

  14. Muon g-2 (case II) Bend up • d=(dm2/m2)f: mixing angle • gR(L)gR(L) term same as case I • gRgL term: (chiral enh.) • Cancelation is working at the low mf/my mass ratio region • need larger couplings, smaller mass • From g2<4p and my,f >100GeV: mf<100 TeV, my<fewTeV [mf<100TeV, my<3000TeV (case I)] • For g~ e, d=1, mf=my~3TeV Case II Case I

  15. m LFV (penguins) (case II) meg bound is not always the most stringent one Sensitivities are relaxed

  16. m LFV (penguins) (case II) meg bound is not always the most stringent one mNeN enhanced relatively (B~10-13)

  17. m LFV (Z-penguins) (case II) 10-2 10-7 Z-peg. g-peg. • Z-peng. sensitivity is relaxed in the low mass ratio region, for my=(>)O(300~1000)GeV, Z-peng. has similar (better) sensitivity as the RR g-peng. • Z-peng. is less sensitive than the RL g-peng. unless my is as heavy as O(103) TeV (not supported by g-2) • Z-peng. Is subdominant. • Br(Zme)<10-13~15 [BrUL(Zme)~10-6]

  18. m LFV (boxes) (case II) • Dirac and Majorana cases have different sensitivities • me g+perturbativity (+Dam+edm) exclude some (most) parameter space.

  19. Comparing Br(meg) and Dam • Can be easily satisfied with

  20. Conclusion • Consider y-f loop-induced LFV muon decays. • Bounds are translated to constraints on parameters (couplings and masses) • Muon g-2 favors non-chiral interaction • Z-penguin may play some role Box diagram contributions are highly constrained from other’s • Comparing different cases, we found that: • Case I (no cancellation): • Need fine-tune to satisfy Br(meg) and Dam • m 3e, mNe N bounded by me g (2~3 orders below expt.) • Case II (built-in cancellation): • Mixing angles soften the fine-tune in Br(meg) and Dam • m 3e remains suppressed, mNe N is enhanced (~expt. sensitivity)

More Related