arXiv subjects

F. Buccella

Publications and source records attributed to F. Buccella.

43 records · Page 3Linked to original sources

arXiv1994

Nonleptonic weak decays of charmed mesons

A previous analysis of two-body Cabibbo allowed nonleptonic decays of $D^0$ mesons and of Cabibbo allowed and first-forbidden decays of $D^+$ and $D_s^+$ has been adjourned using more recent experimental data and extended to the Cabibbo forbidden decays of $D^0$. Annihilation and W-exchange contributions as well as final state interaction effects (assumed to be dominated by nearby resonances) have been included and are in fact crucial to obtain a reasonable agreement with the experimental data, which show large flavour SU(3) violations. New fitting parameters are necessary to describe rescattering effects for Cabibbo forbidden $D^0$ decays, given the lack of experimental informations on isoscalar resonances. We keep their number to a minimum - three - using phenomenologically based considerations. We also discuss CP violating asymmetries.

hep-ph↗

arXiv1994

Fermi-Dirac Distributions for Quark Partons

We propose to use Fermi-Dirac distributions for quark and antiquark partons. It allows a fair description of the $x$-dependence of the very recent NMC data on the proton and neutron structure functions $F_2^p(x)$ and $F_2^n(x)$ at $Q^2=4$ GeV$^2$, as well as the CCFR antiquark distribution $x\overline q(x)$. We show that one can also use a corresponding Bose-Einstein expression to describe consistently the gluon distribution. The Pauli exclusion principle, which has been identified to explain the flavor asymmetry of the light-quark sea of the proton, is advocated to guide us for making a simple construction of the polarized parton distributions. We predict the spin dependent structure functions $g_1^p(x)$ and $g_1^n(x)$ in good agreement with EMC and SLAC data. The quark distributions involve some parameters whose values support well the hypothesis that the violation of the quark parton model sum rules is a consequence of the Pauli principle.

hep-ph↗

arXiv1994

Energy-Charge Correlation in the $π^+π^-π^0$ Decay of $K_L$ and of Tagged Neutral Kaons

We relate the asymmetries in the charged pions energy in the decay into $π^+π^-π^0$ of $K_L$ and of the tagged neutral kaons. The former asymmetry is a given combination of $\Re(ε)$, $\Im(ε)$, and $|ε'|$. Moreover, the non-violating CP asymmetry allows a test for the $χ$PT predictions within the Zel'dovich approach for the final state interaction.

hep-ph↗

arXiv1994

Majorana Masses for Neutrinos in SO(10)

We study the predictions for Majorana masses for neutrinos in SO(10) grandunification models. (This paper precedes and is cited in the article "PROTON DECAY AND NEUTRINO MASSES IN SO(10)", hep-ph/9405332)

hep-ph↗

arXiv1994

Proton Decay and Neutrino Masses in SO(10)

In the last few years physicists have been looking at $SO(10)$ GUT models with renewed attention because it has been realized that the SU(5) minimal model cannot unify the strong, electromagnetic and weak interactions in a way consistent with the experimental values of $α(M_Z)$, $\si$ and $α_S(M_Z)$. In this paper we derive lower limits on neutrino masses, relevant for cosmology and for the solar-neutrino problem, from necessary consistency conditions on a class of $SO(10)$ models with $\sq$ or $\stt$ intermediate gauge symmetry.

hep-ph↗

arXiv1993

Nonleptonic Cabibbo Favoured $B$-Decays and $CP$-Asymmetries for Charmed Final Hadron States in Isgur and Wise Theory

The Cabibbo allowed non-leptonic $B$-decays in two hadrons are studied, within the factorization hypothesis, in the framework of Isgur and Wise theory for the matrix elements of the $ΔB=-ΔC=\pm 1$ weak currents. The $SU(2)_{HF}$ symmetry relates $|ΔB|=1$ to $|ΔC|=1$ currents, which have been measured in the semileptonic strange decays of charmed particles. By assuming colour screening and allowing for $SU(3)$ invariant contributions from the annihilation terms with charmed final states one is able to comply with the present experimental knowledge.\\ The $CP$ violating asymmetries in neutral $B$ decays are given for charmed final states in terms of the $K-M$ angles. With the central values found for the annihilation parameters there is a destructive (constructive) interference between the direct and annihilation terms in the Cabibbo allowed (doubly forbidden) amplitudes for the decays into $D^{0}(D^{*0})π^0$ and $D^0ρ^0$ so that they may be of the same order. This would imply large asymmetries, for which however our present knowledge on the amplitudes does not allow to predict even their sign.\\ We have better confidence in our predictions for the charged final states than the neutral ones and can draw the conclusion that the detection of the corresponding asymmetries requires, at least, $10^6$ tagged neutral $B$-particles.

hep-ph↗

arXiv1992

CP violating asymmetries in charged D meson decays

The CP violating asymmetries for Cabibbo suppressed charged D meson decays in the standard model are estimated in the factorized approximation, using the two-loop effective hamiltonian and a model for final state interactions previously tested for Cabibbo allowed D decays. No new parameters are added. The predictions are larger than expected and not too far from the experimental possibilities.

hep-ph↗