2010/12/31 by Michael Benzke, Seung J. Lee, Matthias Neubert +1 · 88 citations
Physics and Astronomy · #Amplitude #Asymmetry #B meson #Hadron #Lambda #Meson #Neutrino Physics Research #Particle physics #Particle physics theoretical and experimental studies #Physics #Physics beyond the Standard Model #Quantum Chromodynamics and Particle Interactions #Quantum chromodynamics #Quantum mechanics #Quark #hep-ph
paper · pdf · doi:10.1103/physrevlett.106.141801
published in Physical Review Letters 106(14), 141801 (American Physical Society) · 4 pages
openalex publication_date 2011/04/04 · arxiv created 2011/04/27 · arxiv updated 2011/04/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We show that in the standard model the parametrically leading (by a factor 1/\ensuremathαs) contribution to the inclusive CP asymmetry in B\ensuremath→Xs,d\ensuremathγ 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 \stackrel\texttildelow\ensuremathΛ17u, we predict a value in the range \ensuremath-0.6%<A_Xs\ensuremathγSM<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 \ensuremath-2% was found. A cleaner probe of new physics is offered by the difference of the CP asymmetries in charged versus neutral B\ensuremath→Xs\ensuremathγ decays.