arXiv subjects

Carlos E. Vera

Publications and source records attributed to Carlos E. Vera.

3 recordsLinked to original sources

arXiv2017

Mass spectrum and decay constants of radially excited vector mesons

We calculate the masses and weak decay constants of flavorless ground and radially excited $J^P=1^-$ mesons and the corresponding quantities for the K^*, within a Poincaré covariant continuum framework based on the Bethe-Salpeter equation. We use in both, the quark's gap equation and the meson bound-state equation, an infrared massive and finite interaction in the leading symmetry-preserving truncation. While our numerical results are in rather good agreement with experimental values where they are available, no single parametrization of the QCD inspired interaction reproduces simultaneously the ground and excited mass spectrum, which confirms earlier work on pseudoscalar mesons. This feature being a consequence of the lowest truncation, we pin down the range and strength of the interaction in both cases to identify common qualitative features that may help to tune future interaction models beyond the rainbow-ladder approximation.

hep-ph↗

arXiv2017

Analysis of the nonleptonic charmonium modes $B_s^0 \to J/ψf_{2}^{\prime}(1525)$ and $B_s^0 \to J/ψK^+K^-$

In this work, we present an analysis of the nonleptonic charmonium modes $B_s^0 \to J / ψf_2^\prime(1525)$ and $B_s^0 \to J/ψK^+K^-$. Within the framework of the factorization approach and using the perturbative QCD for the evaluation of the relevant form factors, we find a branching fraction for the two-body channel of BR$(B_s^{0} \to J/ψf_2^{\prime}(1525)) = (1.6 {}^{+0.9}_{-0.7})\times 10^{-4}$ which is in agreement with the experimental values reported by the LHCb and Belle Collaborations. The associated polarization fractions to this vector-tensor mode are also presented. On the other hand, non-resonant and resonant contributions to the three-body decay $B_s^0 \to J/ψK^+K^-$ are carefully investigated. The dominant contributions of the resonances $ ϕ(1020)$ and $f_2^{\prime}(1525)$ are properly taken into account. A detailed analysis of the $K^+ K^-$ invariant mass distributions and Dalitz plot are also performed. The overall result BR$(B_s^{0} \to J/ψK^+ K^-) = (9.3^{+1.3}_{-1.1})\times 10^{-4}$ is also in satisfactory agreement with the experimental information reported by LHCb and Belle.

hep-ph↗

arXiv2016

Sensitivity to Majorana neutrinos in $ΔL=2$ decays of $B_c$ meson at LHCb

The possible existence of Majorana neutrinos can be tested through the study of processes where the total lepton number $L$ is violated by two units ($ΔL=2$). In this work, the production of an on-shell Majorana neutrino with a mass around $\sim$ 0.2 GeV to a few GeV is studied in $ΔL= 2$ decays of the $B_c$ meson. We focus on the same-sign di-muon channels: three-body $B_c^- \to π^+μ^-μ^-$ and four-body $B_c^- \to J/ψπ^+μ^-μ^-$ and their experimental sensitivity at the LHCb. In both channels, we find that sensitivities on the branching fraction of the order $\lesssim 10^{-7} \ (10^{-8})$ might be accessible at the LHC run 2 (future LHC run 3), allowing us to set additional and complementary constraints on the parameter space associated with the mass and mixings of the Majorana neutrino. In particular, bounds can be obtained on the mixing $|V_{μN}|^2 \sim \mathcal{O}(10^{-5}-10^{-4})$ that are similar or better than the ones obtained from heavy meson $ΔL=2$ decays: $D_{(s)}^- \to π^+μ^-μ^-$ and $B^- \to π^+μ^-μ^- \ (D^0π^+μ^-μ^-)$.

hep-ph↗