arXiv subjects

D. Zappala

Publications and source records attributed to D. Zappala.

6 recordsLinked to original sources

arXiv2013

Neutron Star masses from the Field Correlator Method Equation of State

We analyse the hadron-quark phase transition in neutron stars by confronting the hadronic Equation of State (EoS) obtained according to the microscopic Brueckner-Hartree-Fock many body theory, with the quark matter EoS derived within the Field Correlator Method. In particular, the latter EoS is only parametrized in terms of the gluon condensate and the large distance quark-antiquark potential, so that the comparison of the results of this analysis with the most recent measurements of heavy neutron star masses provides some physical constraints on these two parameters.

hep-ph↗

arXiv2013

Quark matter in Neutron Stars within the Field Correlator Method

We discuss the appearance of quark matter in neutron star cores', focussing on the possibility that the recent observation of a very heavy neutron star could constrain free parameters of quark matter models. For that, we use the equation of state derived with the Field Correlator Method, extended to the zero temperature limit, whereas for the hadronic phase we use the equation of state obtained within both the non-relativistic and the relativistic Brueckner-Hartree-Fock many-body theory. We find a strong dependence of the maximum mass both on the value of the q\bar q interaction V_1, and on the gluon condensate G_2, for which we introduce a dependence on the baryon chemical potential mu_B. We find that the maximum masses are consistent with the observational limit for not too small values of V_1.

hep-ph↗

arXiv2005

Nambu Jona-Lasinio Model of \bar q q Bose Einstein Condensation and pseudogap phase

We show the existence of a pseudogap phase in the Nambu Jona-Lasinio model of quark interactions. In the pseudogap phase chiral symmetry is restored but q\bar q pseudoscalar mesons still exist and they are massive. Such a behavior is intermediate between a BCS superconductor and a Bose Einstein Condensate. We suggest the relevance of this phenomenon for an understanding of recent lattice QCD and experimental data.

hep-ph↗

arXiv2003

Noncommutative Synchrotron

We study the departures from the classical synchrotron radiation due to noncommutativity of coordinates. We find that these departures are significant, but do not give tight bounds on the magnitude of the noncommutative parameter. On the other hand, these results could be used in future investigations in this direction. We also find an acausal behavior for the electromagnetic field due to the presence in the theory of two different speeds of light. This effect naturally arises even if only θ^{12} is different from zero.

hep-th↗

arXiv1994

Hadronic Spectrum in Inclusive Semileptonic B Decays

We evaluate the inclusive semileptonic B decay spectrum as a function of the final-state hadrons energy to second order in the inverse quark mass expansion and tree level in $α_{s}$. We argue that there is an energy interval below the $c$ production threshold that could be used to determine $V_{ub}$.

hep-ph↗

arXiv1993

Higgs Boson Interference in $γγ\rightarrow W^+W^-$

We study interference effects between resonant and nonresonant amplitudes for the $γγ\rightarrow W^+ W^-$ process at a backscattered photon-photon collider. We show that a Higgs boson with $M_H$ > 200 GeV is manifest as a resonant dip in the $W^+W^-$ invariant mass spectrum and we investigate its statistical significance.

hep-ph↗