0000000000109040
AUTHOR
Daniel Gómez Dumm
showing 5 related works from this author
Magnetic field driven enhancement of the weak decay width of charged pions
2020
We study the effect of a uniform magnetic field B→ on the decays π⁻ → l⁻ ν⁻l, where l⁻ = e⁻, μ⁻, carrying out a general analysis that includes four π⁻ decay constants. Taking the values of these constants from a chiral effective Nambu-Jona-Lasinio (NJL) model, it is seen that the total decay rate gets strongly increased with respect to the B = 0 case, with an enhancement factor ranging from ∼ 10 for eB = 0.1 GeV² up to ∼ 10³ for eB = 1 GeV². The ratio between electronic and muonic decays gets also enhanced, reaching a value of about 1 : 2 for eB = 1 GeV². In addition, we find that for large B the angular distribution of outgoing antineutrinos shows a significant suppression in the direction…
Eta Gamma Z anomaly from the eta ->gamma mu(+)mu(-) decay
1998
We show that the eta gamma Z anomaly can be measured by analysing parity-violating effects in the eta --> gamma mu(+)mu(-) decay. In this sense, we find that the longitudinal polarization of the outgoing mu(+) is an appropriate observable to be considered in future high-statistics eta factories. The effect is expected to lie in the range 10(-5)-10(-6) in the Standard Model.
Long-distance contributions to the K-L ->mu(+)mu(-) decay width
1998
The dispersive two-photon contribution to the K-L --> mu(+)mu(-) decay amplitude is analyzed, using chiral perturbation theory techniques and large-N-C considerations. A consistent description of the decays pi(0) --> e(+)e(-), eta --> mu(+)mu(-), and K-L --> mu(+)mu(-) is obtained. As a by-product, one predicts B(eta --> e(+)e(-)) = (5.8 +/- 0.2) X 10(-9) and B(K-L --> e(+)e(-)) = (9.0 +/- 0.4) X 10(-12).
Hadron structure in tau -> KK pi nu_tau decays
2009
We analyze the hadronization structure of both vector and axial-vector currents leading to tau -> KK pi nu(tau) decays. At leading order in the 1/N-C expansion, and considering only the contribution of the lightest resonances, we work out, within the framework of the resonance chiral Lagrangian, the structure of the local vertices involved in those processes. The couplings in the resonance theory are constrained by imposing the asymptotic behavior of vector and axial-vector spectral functions ruled by QCD. In this way we predict the hadron spectra and conclude that, contrary to previous assertions, the vector contribution dominates by far over the axial-vector one in all KK pi charge channe…
tau ->pi pi pi nu(tau) decays in the resonance effective theory
2004
tau-->pipipinu(tau) decays are analyzed within the framework of the resonance effective theory of QCD. We work out the relevant Lagrangian that describes the axial-vector current hadronization contributing to these processes, in particular the local a(1)(1260)-rho(770)-Goldstone interactions. The new coupling constants are constrained by imposing the asymptotic behavior of the corresponding spectral function within QCD. Hence we compare the theoretical framework with the experimental data, obtaining a good quality fit from the ALEPH spectral function and branching ratio. We also get values for the mass and on-shell width of the a(1)(1260) resonance. In this way we are able to provide the st…