arXiv subjects

Franco Buccella

Publications and source records attributed to Franco Buccella.

25 records · Page 2Linked to original sources

arXiv2009

Hints for the existence of hexaquark states in the baryon-antibaryon sector

The discovery of some baryon-antibaryon resonances has led us to consider 3q~3\bar{q} systems as possible candidates. We predict their spectrum in the framework of a constituent model, where the chromo-magnetic interaction plays the main role. The relevant parameters are fixed by the present knowledge on tetraquarks. The emerging scenario complies well with experiment. Besides the description of the baryon-antibaryon resonances, we find evidence for new tetraquark states, namely the a0(Y) in the hidden strangeness sector and, in the cs\bar{c}\bar{s} sector, the Y(4140) and the X(4350). A detailed account of the spectra and the decay channels is provided for future comparisons with data.

hep-ph↗

arXiv2007

Strangeness asymmetry of the nucleon in the statistical parton model

We extend to the strange quarks and antiquarks, the statistical approach of parton distributions and we calculate the strange quark asymmetry $s-\bar s$. We find that the asymmetry is small, positive in the low $x$ region and negative in the high $x$ region. In this framework, the polarized strange quarks and antiquarks distributions, which are obtained simultaneously, are found to be both negative for all $x$ values.

hep-ph↗

arXiv2007

Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty.

hep-ph↗

arXiv2005

The extension to the transverse momentum of the statistical parton distributions

By extending the statistical distributions to the transverse degree of freedhom, we account for a multiplicative factor in the Fermi-Dirac functions of the light quarks, we were led to introduce in a previous work to comply with experiment. We can also get light antiquark distributions, similar to those we proposed earlier

hep-ph↗

arXiv2005

The statistical parton distributions: status and prospects

New experimental results on polarized structure functions, cross sections for $e^{\pm}p$ neutral and charge current reactions and $ν$ ($\barν$) charge current on isoscalar targets are compared with predictions using the statistical parton distributions, which were previously determined. New data on cross sections for Drell-Yan processes, single jet in $p\bar{p}$ collisions and inclusive $π^0$ production in $pp$ collisions are also compared with predictions from this theoretical approach. The good agreement which we find with all these tests against experiment, strenghtens our opinion on the relevance of the role of quantum statistics for parton distributions. We will also discuss the prospects of this physical framework.

hep-ph↗

arXiv2000

Testing kappa-Poincare' with neutral kaons

In recent work on experimental tests of quantum-gravity-motivated phenomenological models, a significant role has been played by the so-called ``$κ$'' deformations of Poincaré symmetries. Sensitivity to values of the relevant deformation length $λ$ as small as $5 \cdot 10^{-33}m$ has been achieved in recent analyses comparing the structure of $κ$-Poincaré symmetries with data on the gamma rays we detect from distant astrophysical sources. We investigate violations of CPT symmetry which may be associated with $κ$-Poincaré in the physics of the neutral-kaon system. A simple estimate indicates that experiments on the neutral kaons may actually be more $λ$-sensitive than corresponding astrophysical experiments, and may already allow to probe values of $λ$ of order the Planck length.

hep-ph↗

arXiv1995

Spontaneously Broken SU(5) Symmetries and One-Loop Effects in the Early Universe

This paper studies one-loop effective potential and spontaneous-symmetry-breaking pattern for SU(5) gauge theory in de Sitter space-time. Curvature effects modify the flat-space effective potential by means of a very complicated special function previously derived in the literature. An algebraic technique already developed by the first author to study spontaneous symmetry breaking of SU(n) for renormalizable polynomial potentials is here generalized, for SU(5), to the much harder case of a de Sitter background. A detailed algebraic and numerical analysis provides a better derivation of the stability of the extrema in the maximal subgroups SU(4) x U(1), SU(3) x SU(2) x U(1), SU(3) x U(1) x U(1) x R(311), SU(2) x SU(2) x U(1) x U(1) x R(2211), where R(311) and R(2211) discrete symmetries select particular directions in the corresponding two-dimensional strata. One thus obtains a deeper understanding of the result, previously found with a different numerical analysis, predicting the slide of the inflationary universe into either the SU(3) x SU(2) x U(1) or SU(4) x U(1) extremum. Interestingly, using this approach, one can easily generalize all previous results to a more complete SU(5) tree-level potential also containing cubic terms.

gr-qc↗