Thomas Mannel

Baryons in the heavy quark effective theory

We show how to incorporate baryons in the heavy quark effective theory. A convenient formalism is exhibited and applied to semileptonic weak decays of heavy baryons. In general, the heavy quark effective theory reduces the number of form factors necessary to describe the matrix elements for transitions among heavy baryons. We also note that in semileptonic weak decays of Δc one arrives at an important and experimentally testable prediction that two form factors suffice to describe this process. As a further application of the formalism we discuss exclusive production of heavy baryons in e+e− annihilation.

Form-factors from light-cone sum rules with B-meson distribution amplitudes

New sum rules for B{yields}{pi},K and B{yields}{rho},K* form factors are derived from the correlation functions expanded near the light cone in terms of B-meson distribution amplitudes. The contributions of quark-antiquark and quark-antiquark-gluon components in the B meson are taken into account. Models for the B-meson three-particle distribution amplitudes are suggested, based on QCD sum rules in heavy-quark effective theory. Employing the new light-cone sum rules, we calculate the form factors at small momentum transfers, including SU(3)-violation effects. The results agree with the predictions of the conventional light-cone sum rules.

Precision Physics with

CP-violating effects in the time-dependent angular distribution of the B^0_s -> J/psi[-> ell^+ ell^-] phi[-> K^+K^-] decay products play a key role for the search of new physics. The hadronic Standard-Model uncertainties are related to doubly Cabibbo-suppressed penguin contributions and are usually assumed to be negligibly small. In view of recent results from the Tevatron and the quickly approaching start of the data taking at the LHC, we have a critical look at the impact of these terms, which could be enhanced through long-distance QCD phenomena, and explore the associated uncertainty for the measurement of the CP-violating B^0_s-\bar B^0_s mixing phase. We point out that these effects can actually be controlled by means of an analysis of the time-dependent angular distribution of the B^0_s -> J/psi[-> ell^+ ell^-] \bar K^{*0}[-> pi^+ K^-] decay products, and illustrate this through numerical studies. Moreover, we discuss SU(3)-breaking effects, which limit the theoretical accuracy of our method, and suggest internal consistency checks of SU(3).

B^0_s \to J/\psi \phi

Abstract Inclusive semileptonic decays are discussed in the framework of heavy quark effective field theory by employing the short-distance expansion in the effective theory. The lowest order term turns out to be the parton model; the higher order terms may be regarded as correction terms to the parton model result. The first nonvanishing corrections to the parton model result are given and the lepton energy spectrum of inclusive semileptonic decays of heavy mesons is calculated.

at the LHC: The Quest for New Physics

The gauge sector of the standard model exhibits a flavor symmetry that allows for independent unitary transformations of the fermion multiplets. In the standard model the flavor symmetry is broken by the Yukawa couplings to the Higgs boson, and the resulting fermion masses and mixing angles show a pronounced hierarchy. In this work we connect the observed hierarchy to a sequence of intermediate effective theories, where the flavor symmetries are broken in a stepwise fashion by vacuum expectation values of suitably constructed spurion fields. We identify the possible scenarios in the quark sector and discuss some implications of this approach.

Operator product expansion for inclusive semileptonic decays in heavy quark effective field theory

Abstract Employing the light-cone sum rule approach in QCD, we relate the B -meson distribution amplitude to the B → π form factor at zero momentum transfer. In leading order, the sum rule is converted into a simple expression for the inverse moment λ B of the distribution amplitude ϕ + B . Using as an input the B → π form factor calculated from the light-cone sum rule in terms of pion distribution amplitudes, we obtain an estimate: λ B = 460 ± 160 MeV . We investigate how this result is modified by the B -meson three-particle distribution amplitudes.

Sequential flavor symmetry breaking

The general structure of the 1/m corrections at zero recoil is studied. The relevant matrix elements are forward matrix elements of local higher dimensional operators and their time ordered products with higher order terms from the Lagrangian. These matrix elements may be classified in a simple way and the analysis at the nonrecoil point for the form factor of heavy quark currents simplifies drastically. The second order recoil corrections to the form factor

B-meson distribution amplitude from the B → π form factor

{\mathit{h}}_{\mathit{A}1}

Higher order 1/m corrections at zero recoil.

of the axial vector current, relevant for the \ensuremath{\Vert}

Resummation of nonperturbative corrections to the lepton spectrum in inclusive B-->Xql nu -bar decays.

{\mathit{V}}_{\mathit{c}\mathit{b}}