Related papers: Computing one-loop radiative corrections in $\tau …
The $P$-wave charmonium decays $h_{c}\rightarrow\gamma\eta^{(\prime)}$ are revisited by taking into account relativistic corrections. The decay amplitudes are derived in the Bethe-Salpeter formalism, in which the involved one-loop integrals…
Radiative corrections to the $h\rightarrow Z\gamma$ are evaluated in the one-loop approximation. The unitary gauge gauge is used. The analytic result is expressed in terms of the Passarino-Veltman functions. The calculations are applicable…
We study the unknown coupling constants that appear at order $p^4$ in the Chiral Perturbation Theory analysis of $K \to \pi \gamma^* \to \pi l^+ l^-$, $K^{+-} \to \pi^{+-} \gamma \gamma$ and $K \to \pi \pi \gamma$ decays. To that end, we…
Leading-order electromagnetic loop corrections to the one-pion-exchange potential are computed within the framework of chiral perturbation theory. These corrections generate an effective nucleon-nucleon potential, $V_{\pi \gamma}$, which…
Within Chiral Perturbation Theory (CHPT) we compute the form factors A, V and $\gamma = A/V$ in the $\pi \to \nu l \gamma$ decay to $O(p^6)$. A and $\gamma$ obtain corrections of order 25%.
We evaluate radiative decays of $\rho$ and $\omega$ going to two neutral mesons, $\pi^{0} \pi^{0}$ and $\pi^{0} \eta$. We use the sequential vector decay mechanisms in addition to chiral loops and $\rho$-$\omega$ mixing. The chiral loops…
We test whether or not the tau lepton manifests the same couplings as the mu lepton by investigating the relative decay rates in purely leptonic D+ meson decays. Specifically, we place the first upper limit on the ratio R=Gamma(D+ -> tau+…
In this paper we compute one-loop corrections to masses and couplings in the minimal supersymmetric standard model. We present explicit formulae for the complete corrections and a set of compact approximations which hold over the unified…
The decays tau -> 3 pi + nu(tau) are analyzed at one loop order in the framework of Generalized Chiral Perturbation Theory, in order to test the sensitivity to the size of spontaneous chiral symmetry breaking parameters, contained in the…
We evaluate the impact of radiative corrections in the ratios $\Gamma[B\to M \mu^+\mu^-]/\Gamma[B\to M e^+e^-]$ when the meson $M$ is a $K$ or a $K^*$. Employing the cuts on $m^2_{\ell\ell}$ and the reconstructed $B$-meson mass presently…
This PhD thesis studies some hadronic and radiative decays of the tau lepton using a Chiral Lagrangian including resonance fields. After a theoretical introduction, the decays to the $(\pi \pi \pi)^-$, $(KK\pi)^-$ and $\eta^{(\prime)} \pi^-…
The first searches for $B^0\to K^+\pi^-\tau^+\tau^-$ and $B^0_s\to K^+K^-\tau^+\tau^-$ decays at the LHCb experiment are conducted with $pp$ collision data corresponding to an integrated luminosity of $5.4\textrm{ fb}^{-1}$. The tau leptons…
The QCD corrections to the R_{\tau}^{12} moment of the invariant mass distribution in hadronic decays of the tau lepton are discussed. The next-to-next-to-leading order prediction is shown to be stable with respect to change of the…
We present the differential rates and branching ratios of the radiative decays $\tau \to l \bar{\nu} \nu \gamma$, with $l=e$ or $\mu$, and $\mu \to e \bar{\nu} \nu \gamma$ in the Standard Model at next-to-leading order. Radiative…
In a supersymmetric model with the lightest supersymmetric particle (LSP) $\chi$ in the range of a few hundred MeV's, the decay $\tau {\longrightarrow} \mu \chi \chi$ is going to be allowed. We investigate the departure from…
We improve the calculations of the $\eta \to \pi^0 \gamma \gamma$ decay within the context of meson chiral lagrangians. We use a chiral unitary approach for the meson-meson interaction, thus generating the $a_0(980)$ resonance and fixing…
The branching fractions of radiative leptonic $\tau$ decays $(\tau \to l \nu \bar{\nu} \gamma$, $l=e,\mu)$ were recently measured by the Babar collaboration with a relative error of about 3%. The measurement of the branching ratio…
The long-distance electromagnetic radiative corrections to tau- -> pi- pi0 nu are re-evaluated. A meson dominance model is used to describe the emission of real photons in this decay. Results obtained for the hadronic spectrum and the decay…
Within the resonance chiral theory, we have studied the process of a tau lepton decaying into a vector resonance plus a pseudo-Goldstone meson and a tau neutrino. Two kinds of processes are discussed: (a) tau- --> (rho pi-,omega pi-, phi…
We discuss the test of CP and CPT violation in $\tau$ decay without using the polarized electron beam by comparing partial fractions of $\tau^-$ and $\tau^+$ decay into channels with strong final state interactions. For example,…