Related papers: NNLO QCD corrections to the m_c dependent matrix e…
We compute the NNLO QCD corrections for the hadroproduction of a pair of off-shell photons in the limit of a large number of quark flavors. We perform a reduction of the two-loop amplitude to master integrals and calculate the latter…
An analytic result for the O(alpha_s corrections to the triple differential B -> X_u l nu decay rate is presented, to leading order in the heavy-quark expansion. This is relevant for computing partially integrated decay distributions with…
Distributions of charged leptons in semileptonic $\Lambda_c$ and $\Lambda_b$ decays can be used as spin analysers for the corresponding charm and bottom quarks. QCD corrections to the energy spectra of charged leptons have been given in the…
We present a calculation of the ratio of the charm quark mass to the strange quark mass. Using the Brillouin improved Wilson action, we are able to calculate this ratio in a single framework, using a relativistic fermionic action…
We show that one can re-arrange the Heavy Quark Expansion for inclusive weak decays of charmed hadrons in such a way that the resulting expansion is an expansion in $\Lambda_{\rm QCD} / m_c$ and $\alpha_s (m_c)$ with order-one coefficients.…
A physically defined effective charge can incorporate quark masses analytically at the flavor thresholds. Therefore, no matching conditions are required for the evolution of the strong coupling constant through these thresholds. In this…
We calculate the complete ${\cal O}(\alpha_s)$ corrections to the quark decay $b\to ccs$ taking full account of the quark masses, but neglecting penguin contributions. For a c to the b quark mass ratio $m_c/m_b= 0.3$ and a strange quark…
We calculate the next-to-next-to-leading-order (NNLO) perturbative corrections to $P$-wave quarkonia annihilation decay to two photons, in the framework of nonrelativistic QCD (NRQCD) factorization. The order-$\alpha_s^2$ short-distance…
The experimental and theoretical status of the inclusive decay B -> X_s gamma is briefly summarized. Results from a very recent theoretical analysis are reported. An ~11% increase in the SM prediction for BR[ B -> X_s gamma] is found after…
We present three-loop (NNNLO) corrections to the heavy-to-heavy quark transitions in the limit of equal initial and final quark masses. In analogy with the previously found NNLO corrections, the bulk of the result is due to the beta_0^2…
We compute the virtual O(\alpha_s^3 n_f^2) corrections to the heavy quark vector current correlator in terms of expansions in the external momentum and as an exact numerical solution. As a byproduct, the available high-energy expansion at…
Using domain wall fermions, we estimate $B_K(\mu\approx 2 GeV)=0.628(47)$ in quenched QCD which is consistent with previous calculations. At $\gbeta=6.0$ and 5.85 we find the ratio $f_K/m_\rho$ in agreement with the experimental value,…
We present the calculation of the virtual- and bremsstrahlung corrections of O(alpha_s) to the matrix elements <d l+ l-|O_i|b>. This is the missing piece in the NNLL results for various observables associated with the process B-> X_d l+ l-,…
We present the next-to-next-to-leading order (NNLO) QCD corrections to the decay constants for both the pseudoscalar and vector beauty-charmed mesons $B_{c}$ and $B^*_{c}$ in nonrelativistic QCD effective theory. Explicit NNLO calculation…
In this paper, we present preliminary results of the determination of the charm quark mass $\hat{m}_c$ from QCD sum rules of moments of the vector current correlator calculated in perturbative QCD at ${\cal O} (\hat \alpha_s^3)$.…
The NLO contributions to some two-body charmless hadronic B meson decays, such as those from the QCD vertex corrections, the quark loops and the chromo-magnetic penguins, have been calculated in the pQCD factorization approach.
The gluino-induced contributions to the decay b-> s gamma are investigated in supersymmetric frameworks with generic sources of flavour violation. It is shown that, when QCD corrections are taken into account, the relevant operator basis of…
The recent LHCb angular analysis of the exclusive decay B->K^*mu+mu- has indicated significant deviations from the Standard Model expectations. Accurate predictions can be achieved at large K*-meson recoil for an optimised set of…
I review the NLO QCD calculations of the branching ratio for B--> X_s gamma in the SM. Including the leading electromagnetic corrections, one obtaines BR(B-> X_s gamma)=(3.32 +- 0.30)*10^{-4}. Confronting theory with the newest data, an…
We compute next-to-leading order QCD corrections to the $1/m_b^2$ terms of the Heavy Quark Expansion for the contribution to inclusive nonleptonic bottom hadron decays induced by the charged-current operators mediating the transitions $b…