A like-sign dimuon charge asymmetry induced by the anomalous top quark couplings 이 강 영 (건국대학교) @ 연세대학교, 서울 2010. 11. 30.

Based on J. P. Lee and KYL, arXiv:1010.6132. J. P. Lee and KYL, Phys. Rev. D 78, 056004 (2008). KYL and W. Y. Song, Phys. Rev. D 66, 057901 (2002).

Contents Introduction D0 like-sign dimuon charge asymmetry Constraints Results Top quark decays Summary

Introduction Like-sign dimuon charge asymmetry measured by D0 at Tevatron shows 3.2 σ deviation from the SM prediction. More than 108-109 top quarks will be produced at LHC in a year (at full power run). Top quark couplings will be directly tested and nondiagonal couplings may be observed at LHC. Anomalous top quark couplings are worth examining at present.

The CKM matrix Not directly measured >0.74 without unitarity 2008 Nobel prize awarded Not directly measured >0.74 without unitarity D0 PRD78, 012005 (2008) CDF Note 8968

Underlying new physics Effective Lagrangian Vtqeff : measures SM-like left-handed couplings ξq : measures right-handed couplings New particles, neutral current interactions are ignored. Underlying new physics Effective electroweak chiral Lagrangian General Left-Right model (VLCKM≠VRCKM) Etc.

D0 like-sign dimuon charge asymmetry production at Tevatron One muon comes from direct semileptonic decay : The other muon comes from semileptonic decay after neutral B meson mixing :

The dimuon charge asymmetry of semileptonic B decays is defined by : Number of events of two b hadrons decaying into two muons with the charge of the same sign comes from the asymmetry of the “wrong sign” semileptonic decays, which are due to the oscillations of neutral Bd and Bs mesons.

Since both Bd and Bs mesons are produced at the Tevatron, is a linear combination of and . Y. Grossman, Y. Nir, G. Raz, PRL 97, 151801 (2006)

- The Standard Model Predictions Non-zero Difference between Bq and Bq decays Mixing induced CP violation A. Lenz, U. Nierste, JHEP 0706, 072 (2007)

D. Tsybychev, Talk given at the Johns Hopkins Workshop

measurements arXiv:1005.2757 [hep-ex] The measured value shows deviations from the standard model prediction. Previous measurement

Constraint I : B→Xsγ decays ΔB=1 effective Hamiltonian Oi : SM operators Oi‘ : chiral conjugate operators SM Wilson coefficients

Turn on the right-handed couplings with the new loop functions

World average value of measurement Branching ratio A.L. Kagan, M. Neubert, EPJ, C7, 5 (1999) M. Misiak and M. Steinhauser, NPB 764, 62 (2007) M. Misiak et al., PRL 98, 022002 (2007). SM prediction at NNLO for World average value of measurement HFAG

Constraint II : Bq-Bq mixing Schreodinger equation Mass and width differences Note that

Transition amplitude with

SM predictions Measurements A. Lenz and U. Nierste, JHEP 06, 072 (2007) Measurements HFAG CDF, PRL 97, 242003 (2006) D0, D0 note 5618-CONF

Results B→Xsγ B→Xsγ + Bs mixing ξb =0 We obtain

ξs =0 We obtain

- - - No CP violation is predicted in Bs-Bs mixing in the SM. (No phase in Vts and Vtb) Combined analysis of current data of Bs-Bs mixing tells us that there exists some CP violation. Our prediction of the phase of M12s is dominated by the phase of Vtseff. The phase of Bd-Bd mixing is directly measured. - -

ξb =0 A. Lenz and U. Nierste, JHEP 06, 072 (2007)

Bs mixing Bd mixing sin 2β ξs =0

Including dimuon charge asymmetry data ξb =0 Including dimuon charge asymmetry data B→Xsγ B→Xsγ + Bs mixing B→Xsγ + Bs mixing + Aslb

ξb =0

ξs =0 B→Xsγ B→Xsγ + Bs mixing B→Xsγ + Bs mixing + Bd mixing B→Xsγ + Bs mixing + Bd mixing + Aslb

ξs =0

Wts Wtb

Top quark decays Nondiagonal top quark decays in the SM, but shifted in our approach, which is insensitive to ξs and directly measure Vtseff . Large deviation from the SM prediction is possible.

Note that in the SM Including dimuon data Can we measure it?

Summary Impact of the anomalous right-handed top quark couplings on the like-sign dimuon charge asymmetry at Tevatron is studied in a model independent way. Under the constraints from B→Xsγ decays and Bq-Bq mixing, the dimuon asymmetry can be explained. Constraints on new physics parameters and predictions of departure from the SM are obtained. Nondiagonal top quark decays might examine the tsW coupling directly and independently. -

Backup Slides

Preliminary Including dimuon charge asymmetry data ξb =0 B→Xsγ B→Xsγ + Bs mixing B→Xsγ + Bs mixing + Aslb Preliminary

ξb =0 Preliminary