Related papers: The b -> s gamma decay revisited
The $H\to \gamma\gamma$ decay is an ideal process to study the structure of next-to-leading power logarithms induced by quarks due to its simple initial and final states. We perform a region analysis of this process up to two-loop level to…
We present the computation of the leading one-loop electroweak radiative corrections to the non-standard top quark decay width Gamma(t->H+ b), using a physically motivated definition of tan(beta). We find that the corrections are large,…
We propose the Z -> gamma gamma decay, a process strictly forbidden in the standard model, as a signal suitable for the search of noncommutativity of coordinates at very short distances. We compute the Z -> gamma gamma partial widthin the…
We demonstrate, by an explicit one-loop calculation, that at leading twist the nonperturbative effects in B -> gamma l nu, B -> gamma gamma and B -> gamma l+ l- radiative decays are contained in a common multiplicative factor…
The increasing precision of many experiments in elementary particle physics leads to continuing interest in perturbative higher order calculations in the electroweak Standard Model or extensions of it. Such calculations are of increasing…
We study the application of the Breitenlohner-Maison-'t Hooft-Veltman (BMHV) scheme of Dimensional Regularization to the renormalization of chiral gauge theories, focusing on the specific counterterm structure required by the…
We report on the status of the ongoing calculation of multiparticle contributions to the inclusive radiative $\bar{B} \rightarrow X_s \gamma$ decay at next-to leading order. This effort amounts to the evaluation of the four-particle process…
A theoretical analysis of the partial inclusive B-->X_s gamma decay rate with a cut E_gamma>E_0 on photon energy must deal with short-distance contributions associated with three different mass scales: the hard scale m_b, an intermediate…
We present an analytical calculation of the next-to-next-to-leading order corrections to the partial decay width $H\to gg$ for a Higgs boson in the intermediate mass range. We apply an asymptotic expansion for $M_H\ll 2M_t$ and compute…
In the standard model, the top quark decay width \Gamma_t is computed from the exclusive t -> bW decay. We argue in favor of using the three body decays t-> bf_i\bar{f}_j to compute \Gamma_t as a sum over these exclusive modes. As dictated…
The most precise comparison between theory and experiment for the B -> Xs l+ l- rate is in the low q^2 region, but the hadronic uncertainties associated with an experimentally required cut on m_X potentially spoil the search for new physics…
We are presenting a method of linear regression based on Gram-Schmidt orthogonal projection that does not compute a pseudo-inverse matrix. This is useful when we want to make several regressions with random data vectors for simulation…
In the past, it was believed that one cannot obtain clean weak-phase information from the measurement of CP-violating asymmetries in 3-body B decays. Recently it was shown that this is not true -- by expressing the decay amplitudes in terms…
In this paper we develop a quantitative version of Enss' method to establish global-in-time decay estimates for solutions to Schr\"odinger equations on manifolds. To simplify the exposition we shall only consider Hamiltonians of the form $H…
The differential decay spectrum $d\Gamma/dE_e dq^2$ for the semileptonic decay of an unpolarized hadron containing a b-quark, and the decay spectrum $d\Gamma/dE_e dq^2 d\!\cos\theta$ for polarized $\Lambda_b$ decay are computed to second…
We compute O(alpha_s^2) QCD corrections to the lepton invariant mass spectrum in the decay b --> u l nu_l, relevant for the determination of the CKM matrix element |V_{ub}|. Our method can also be used to evaluate moments of the lepton…
Off-shell and relativistic bound-state corrections for the decay $t \to b+W$ are calculated to $O(\a_s^2)$ making full use of the Bethe-Salpeter formalism for weakly bound systems. Thus we are able to take into account all terms to that…
Recent advances in the QCD corrections to $b\to s\gamma$ decay in the MSSM include i.) evaluation of the relevant operators, Wilson coefficients and anomalous dimension matrix elements for the various MSSM effective theories valid at scales…
Factorization based on the soft-collinear effective theory (SCET) can be used to reduce the number of hadronic parameters in an isospin analysis of B-> pi pi decays by one. This gives a theoretically precise method for determining the CP…
We give a more complete calculation of $b \to s e^+e^- $ decay including leading log QCD corrections from $m_{top}$ to $M_W$ in addition to corrections from $M_{W}$ to $m_b$. The differential decay rate is found to be slightly suppressed…