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T: Fachverband Teilchenphysik

T 14: Flavorphysik (Theorie) 1

T 14.3: Vortrag

Dienstag, 10. März 2009, 17:15–17:30, M001

QED radiative corrections to semileptonic B decays — •Florian Bernlochner and Heiko Lacker — Humboldt Universität zu Berlin, Berlin, Deutschland

Over the last 10 years an increasing amount of data and a better understanding of detector effects lead to a very accurate picture of physics at the Y(4s) threshold at the B-factory experiments BABAR and Belle. One core task of these sites lies in the determination of the b to u and b to c quark transition elements of the Cabibbo-Kobayashi-Maskawa matrix, Vub and Vcb respectively, from semileptonic B decay rates. In order to match today's precision on the experimental side, one needs a good understanding of photonic correction effects: Occurring virtual and real photons can couple to all charged particles of the initial and final states of the decay process, leading to an overall change of the decay kinematics, shape and rate. These effects usually are studied applying approximative all-purpose algorithms to allready simulated decays, which determine process independent kinematic corrections on the final states. All of these algorithms are based on factorizations of the photonic corrections in the vanishing photon energy limit. This approach is unsatisfying in two ways: first it allows no clear way to determine the accuracy of the algorithm. Second the overall rate and shape changes are neglected. We present the current progress of the theoretical calculations and simulations of the order alpha QED corrections for various semileptonic B to pseudoscalar and B to vector decays, which circumnavigate these issues by an accurate treatment of the photonic corrections.