Related papers: Two-loop QCD corrections to top quark width
We study O(alpha^2 beta_0) perturbative corrections to matrix elements entering two-body exclusive decays of the form B -> pi pi, pi K in the QCD factorization formalism, including chirally enhanced power corrections, and discuss the effect…
We present the complete calculation of the top-quark decay width at next-to-next-to-leading order in QCD, including next-to-leading electroweak corrections as well as finite bottom quark mass and $W$ boson width effects. In particular, we…
We present a calculation of O(\alpha_s) contributions to the process of t-channel single-top production and decay, which include virtual and real corrections arising from interference of the production and decay subprocesses. The…
We consider two-loop QCD corrections to the element $\Gamma_{12}^q$ of the decay matrix in $B_q-\bar{B}_q$ mixing, $q=d,s$, in the leading power of the Heavy Quark Expansion. The calculated contributions involve one current-current and one…
Radiative corrections in the order ${\alpha\over{2\pi}}{{m^2_e}\over m^2_\mu}$ to $\mu $- and ${\alpha\over{2\pi}}{{m^2_\mu}\over m^2_\tau}$ to $\tau $- decays are calculated. The decay width is enhanced by $4.48\cdot 10^{-3}…
We describe a calculation of the fully-differential decay rate of a top quark to a massless $b$-quark and a lepton pair at next-to-next-to-leading order in perturbative QCD. Technical details of the calculation are discussed and selected…
We compute the two-loop BSM contributions to the $h\longrightarrow \gamma\gamma$ decay width in the SM extended with a real triplet of $SU(2)$. We consider scenarios in which the neutral components of doublet and triplet do not mix, so that…
Combining our results for various O(alpha_s^2) corrections to the weak radiative B-meson decay, we are able to present the first estimate of the branching ratio at the next-to-next-to-leading order in QCD. We find BR(B -> X_s gamma) = (3.15…
We evaluate the next-to-leading-order QCD corrections of O(alpha_s^2 G_F M_t^2) to the Standard-Model l^+l^-H, ZZH, and W^+W^-H couplings in the heavy-top- quark limit. Exploiting these results together with knowledge of Delta rho to the…
The leading electroweak MSSM two-loop corrections to the $\rho$-parameter are calculated. They are obtained by evaluating the two-loop self-energies of the Z and the W boson at O(Gf^2 m_t^4) in the limit of heavy scalar quarks. A very…
We calculate the one-loop QCD corrections to $t\rightarrow \tilde t_1 \tilde \chi^0_j$ using dimensional reduction scheme, including QCD and supersymmetric QCD corrections. The analytic expressions for the corrections to the decay width are…
The one-loop supersymmetric QCD quantum effects on the width of the unconventional top quark decay mode $t\rightarrow H^{+}\, b$ are evaluated within the MSSM. The study of this process is useful to hint at the supersymmetric nature of the…
We compute the two-loop BSM contributions to the $h\longrightarrow \gamma\gamma$ decay width in the aligned THDM. We adopt the simplifying assumptions of vanishing EW gauge couplings and vanishing mass of the SM-like Higgs boson, which…
We investigate higher order effects in the nonrelativistic expansion of lattice QCD on the heavy-light meson decay constants and some other quantities in order to understand the truncation error of NRQCD. While our numerical results have…
We compute the complete two-loop O(alpha) Wilson coefficients relevant for radiative decays of the B meson in the SM. This is a necessary step in the calculation of the O(alpha alpha_s^n ln^n m_b/M_W) corrections and improves on our…
The charged-Higgs contributions to the decay \bar{B} -> X_s gamma are discussed in the minimal supersymmetric standard model at large tan beta. These contributions receive two-loop O(alpha_s tan beta) corrections by squark-gluino subloops,…
We introduce an anomalous top quark coupling (right-handed current) into Standard Model Lagrangian. Based on this, a more complete calculation of $b \to s\gamma $ decay including leading log QCD corrections from $m_{top}$ to $M_W$ in…
We analytically compute quadratic mass corrections of order $\alpha_s^3 m_q^2/s$ to the absorptive part of the (non-diagonal) correlator of two axial vector currents. This allows us to find the correction of order $\alpha_s^3 m_q^2/M^2_W$…
We compute the last missing piece of the two-loop ${\cal O}(\alpha \alpha_s)$ corrections to $\gamma t \bar{t}$ vertex at the $t \bar{t}$ threshold due to the exchange of a $W$ boson and a gluon. This contribution constitutes a building…
We calculate the one-loop supersymmetric QCD corrections to the width of the $W$-boson. We find that these are of order $\sim {{ \alpha_s} \over {\pi}} {1 \over 20} { {M^2_W} \over {M_S^2}} \Gamma_{u {\bar d}}$, where $M_S$ is the…