TY - JOUR
T1 - Long-Distance dominance of the CP asymmetry in B̄→X s,dγ decays
AU - Benzke, Michael
AU - Lee, Seung J.
AU - Neubert, Matthias
AU - Paz, Gil
N1 - Copyright:
Copyright 2011 Elsevier B.V., All rights reserved.
PY - 2011/4/4
Y1 - 2011/4/4
N2 - We show that in the standard model the parametrically leading (by a factor 1/αs) contribution to the inclusive CP asymmetry in B̄→Xs,dγ decays arises from a long-distance effect in the interference of the electromagnetic dipole amplitude with the amplitude for an up-quark penguin transition accompanied by soft gluon emission. Using model estimates for the associated hadronic parameter Λ17u, we predict a value in the range -0.6%<AXsγSM<2.8%. In view of current experimental data, a future precision measurement of the flavor-averaged CP asymmetry would signal the presence of new physics only if a value below -2% was found. A cleaner probe of new physics is offered by the difference of the CP asymmetries in charged versus neutral B̄→Xsγ decays.
AB - We show that in the standard model the parametrically leading (by a factor 1/αs) contribution to the inclusive CP asymmetry in B̄→Xs,dγ decays arises from a long-distance effect in the interference of the electromagnetic dipole amplitude with the amplitude for an up-quark penguin transition accompanied by soft gluon emission. Using model estimates for the associated hadronic parameter Λ17u, we predict a value in the range -0.6%<AXsγSM<2.8%. In view of current experimental data, a future precision measurement of the flavor-averaged CP asymmetry would signal the presence of new physics only if a value below -2% was found. A cleaner probe of new physics is offered by the difference of the CP asymmetries in charged versus neutral B̄→Xsγ decays.
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U2 - 10.1103/PhysRevLett.106.141801
DO - 10.1103/PhysRevLett.106.141801
M3 - Article
AN - SCOPUS:79960633580
VL - 106
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 14
M1 - 141801
ER -