arXiv subjects

Antonino Di Piazza

Publications and source records attributed to Antonino Di Piazza.

41 records · Page 3Linked to original sources

arXiv2008

Photon polarization as a probe for quark-gluon plasma dynamics

Prospects of measuring polarized photons emitted from a quark-gluon plasma (QGP) are discussed. In particular, the detection of a possible quark spin polarization in a QGP using circularly polarized photons emitted from the plasma is studied. Photons leave the QGP without further interaction and thus provide a primary probe for quark polarization within the QGP. We find that photon polarization cannot solely arise due to a possible QGP momentum space anisotropy, but may be enhanced due to it. In particular, for oblate momentum distributions and high photon energies, quark polarization is efficiently transfered to photon polarization. The role of competing sources of polarized photons in heavy-ion collisions is discussed.

hep-ph↗

arXiv2007

Production of light particles by very strong and slowly varying magnetic fields

The possibility that around some astrophysical objects there are non-static magnetic fields of enormous intensity suggests that in these situations real particles may be produced. The slowness of the variation is compensated by the huge intensity. The main issue is the production of e+,e- pairs annihilating into photons and the direct production of photons, as one of the concurrent process in the GRB (gamma ray bursts). Then some simple effects due to the presence of the intense gravity are studied and finally a look is given to the production of other kinds of particles.

hep-ph↗

arXiv2006

Particle production in a strong, slowly-varying magnetic field with an application to astrophysics

In this work I studied the production of particles (electron-positron pairs and photons) in the presence of overcritic ($\gg 4.4\cdot 10^{13} \text{gauss}$) slowly varying magnetic fields. The calculations are performed in the framework of QED in the presence of external not quantized electromagnetic fields by means of the adiabatic perturbation theory. Also, since such strong magnetic fields may be present near astrophysical compact objects where gamma-ray bursts (GRB) are thought to be generated, I tried to reproduce theoretically some features of the GRB energy spectra such as the low energy ($\lesssim 0.1 \text{MeV}$) behaviour. Also, having in mind this astrophysical scenario, I took into account the effects of a weak and of a strong gravitational field on the production probabilities previously calculated in the flat Minkowski spacetime.

hep-ph↗

arXiv2006

Pair production in a strong magnetic field: the effect of a strong background gravitational field

We present the calculation of the probability production of an electron-positron pair in the presence of a strong magnetic field with time-varying strength. The calculation takes into account the presence of a strong, constant and uniform gravitational field in the same direction of the magnetic field. The results show that the presence of the gravitational field in general enhances the production of pairs. In particular, high-energy pairs are more likely produced in the presence of the gravitational field than in Minkowski spacetime.

hep-ph↗

arXiv2004

Pair production in a strong slowly varying magnetic field: the effect of a background gravitational field

The production probability of an $e^--e^+$ pair in the presence of a strong, uniform and slowly varying magnetic field is calculated by taking into account the presence of a background gravitational field. The curvature of the spacetime metric induced by the gravitational field not only changes the transition probabilities calculated in the Minkowski spacetime but also primes transitions that are strictly forbidden in absence of the gravitational field.

hep-ph↗