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T: Fachverband Teilchenphysik

T 14: Flavourphysik (Theorie) I

T 14.2: Vortrag

Donnerstag, 31. März 2011, 17:00–17:15, 30.23: 3-1

Charm-loop effect in B to K l l — Alexander Khodjamirian, Thomas Mannel, Alexei Pivovarov, and •Yuming Wang — Theoretische Physik 1,Fachbereich 7 (Physik),Universität Siegen

We calculate the long-distance effect generated by the four-quark operators with c-quarks in the B to K ll decays. At the lepton-pair invariant masses far below the c quark pair threshold, we use OPE near the light-cone. The nonfactorizable soft-gluon emission from c-quarks is cast in the form of a nonlocal effective operator. The B to K matrix elements of this operator are calculatedfrom the B-meson LCSR. To describe the charm-loop effect at large q2, we employ the hadronic dispersion relation with psi=Jpsi,psi(2S), ... contributions, where the measured B to K psi amplitudes are used as inputs. The resulting charm-loop effect is represented as a q2-dependent correction Delta C9(q2) to the Wilson coefficient C9. Within uncertainties of our calculation, at q2 below the charmonium region the predicted ratio Delta C9(q2)/C9 is less than 5 percents for B to K ll, but can reach as much as 20 percents for B to Kstar ll, the difference being mainly caused by the soft-gluon contribution.