Related papers: The B -> X_s gamma Photon Spectrum
In a wide class of models -- including the standard model -- flavor-changing neutral currents are suppressed by an approximate chiral symmetry of the low-energy lagrangian. This symmetry allows the derivation of general relations among…
We compute the leading order (in $\alpha_s$) perturbative QCD and power ($1/m_b^2)$ corrections to the hadronic invariant mass and hadron energy spectra in the decay $B \to X_s \ell^+ \ell^-$ in standard model. This is done both by using…
Interference between the photonic dipole operator Q_7 and the current-current operators Q_{1,2} gives one of the most important QCD corrections to the B -> X_s gamma decay rate. So far, the O(alpha_s^2) part of this correction has been…
We present a systematic evaluation of the shape of the neutrino energy spectrum produced by beta-decay of $^8$B. We place special emphasis on determining the range of uncertainties permitted by existing laboratory data and theoretical…
Consider binary system with a millisecond pulsar ejecting relativistic particles and an optical star emitting soft photons with the energy $\omega \simeq 1-10$ eV. These low-energy photons are scattered by the relativistic electrons and…
We compute long distance effects on the photon energy spectrum in inclusive radiative decays of $B$ mesons using light-cone expansion and heavy quark effective theory. We show that for sufficiently high photon energy the leading…
At the upper endpoint of the photon energy spectrum in Upsilon -> X gamma, the standard NRQCD power counting breaks down and the OPE gives rise to color-octet structure functions. Furthermore, in this kinematic regime large Sudakov…
The ATLAS and CMS Collaborations reported that the observed number of Higgs boson decays into a $Z$ boson and a photon is $\mu = 2.2 \pm 0.7$ times higher than predicted by the Standard Model. Initially, this discrepancy was attributed to a…
In this paper we investigate the hadronic mass spectra of inclusive B decays. Specifically, we study how an upper cut on the invariant mass spectrum, which is necessary to extract V_{ub}, results in the breakdown of the standard…
The pair-production absorption of high-energy gamma-rays by intergalactic low-energy photons is expected to produce a high-energy cutoff in the spectra of extragalactic sources which is a sensitive function of redshift. We first discuss the…
We review some recent theoretical progress in the understanding of weak radiative B meson decay, and discuss the implications of present and improved measurements of b -> s gamma for supersymmetric models.
Theoretical predictions for inclusive semileptonic B decay rates are rewritten in terms of the Upsilon(1S) meson mass instead of the b quark mass, using a modified perturbation expansion. This method gives theoretically consistent and…
The current status of B -> Xs gamma decay rate calculations is summarized. Missing ingredients at the NNLO level are listed. The global normalization factor and non-perturbative effects are discussed. Arguments are presented that results…
We analyze the double radiative B-meson decays B_s -> gamma gamma and B_d -> gamma gamma in QCD factorization based on the heavy-quark limit m_b >> Lambda_QCD. We systematically discuss the various contributions to these exclusive…
Measurements of the rates for the hadronic decays B^+- -> pi K can be used to derive information on the weak phase gamma=arg(V_ub^*) in a largely model-independent way. Hadronic uncertainties can be reduced to the level of nonfactorizable…
Motivated by recent measurements of the radiative decay rates of the \emph{P}-wave spin singlet charmonium $h_c$ to the light meson $\eta$ or $\eta^\prime$ by the BESIII Collaboration, we investigate the decay rates of these channels at…
This Letter addresses the contribution from the light $u , d , s$ quarks to the amplitudes for the decay modes of the Brout-Englert-Higgs scalar boson $H$ into two photons ($H\to\gamma\gamma$) or to a photon and a neutral weak gauge boson…
Motivated by concerns regarding possible two-body contributions to the recently-measured inclusive Upsilon(nS)->gamma+X (n=1, 2, 3) direct photon spectra, we report on a new study of exclusive radiative decays of these narrow Upsilon(nS)…
It is shown that in the decays $B_c(2P)\to B_c^* \gamma^\mathrm{hard}$, $B_c(3P)\to B_c^* \gamma^\mathrm{hard}$ and $B_c(2S)\to B_c^* +\pi^+\pi^-$ followed by the decay $B_c^*\to B_c +\gamma^\mathrm{soft}$ the loss of the soft photon…
A new evaluation of the charged Higgs boson decay $H^+ -> W^+\gamma$ is presented in the context of the general two-Higgs doublet model. A nonlinear $R_\xi$-gauge which considerably simplifies the calculation is introduced and simple…