Sascha Turczyk

Higher order power corrections in inclusive B decays

We discuss order 1/mb4 and 1/mb5 corrections in inclusive semileptonic decay of a B meson. We identify relevant hadronic matrix elements of dimension seven and eight and estimate them using the ground-state saturation approximation. Within this approach the effects on the integrated rate and on kinematic moments are estimated. The overall relative shift in Vcb turns out about +0.4% as applied to the existing fits. Similar estimates are presented for B → Xs + γ decays.

Model-independent analysis of lepton flavour violating τ decays

Many models for physics beyond the Standard Model predict lepton-flavour violating decays of charged leptons at a level which may become observable very soon. In the present paper we investigate the decays of a τ into three charged leptons in a generic way, based on effective-field-theory methods, where the relevant operators are classified according to their chirality structure. We work out the decay distributions and discuss phenomenological implications.

Inclusive Semi-leptonic B Decays to order 1/m 4

We give a systematic way to compute higher orders in the 1/mb expansion in inclusive semi-leptonic decays at tree level. We reproduce the known 1/m 3 terms and compute the 1/m 4 terms at tree level. The appearing non-perturbative parameters and the impact on the determination of Vcb are discussed.

The two roads to ‘Intrinsic Charm’ in B decays

We describe two complementary ways to show the presence of higher order effects in the 1/mQ expansion for inclusive B decays that have been dubbed ‘Intrinsic Charm’. Apart from the lessons they can teach us about QCD’s nonperturbative dynamics their consideration is relevant for precise extractions of |Vcb|: for they complement the estimate of the potential impact of 1/mQ4 contributions. We draw semiquantitative conclusions for the expected scale of Weak Annihilation in semileptonic B decays, both for its valence and non-valence components.

Limits on New Physics from exclusive

We consider the exclusive decays

B \to D^{(*)}\ell \bar\nu

B \to D^{(*)}\,\ell \bar\nu

Decays

and study the effect of non

New ways to search for right-handed current in B→ρℓ

V-A

\bar{ν}

structures on the observables. We extend the standard model hadronic current by additional right-handed vector as well as left- and right-handed scalar and tensor contributions and calculate the decay rates including the perturbative corrections up to order

decay

\alpha_s