Production cross-sections and radiative decay widths of heavy quarkonia in magnetized matter

Abstract

We study the production cross-sections and radiative decay widths of heavy quarkonia (charmonia and bottomonia) in magnetized nuclear matter. The production cross-sections of the [Formula: see text] and [Formula: see text], from the [Formula: see text] and [Formula: see text] scatterings, respectively, are studied from the medium modifications of the masses and partial decay widths to open charm (bottom) mesons, of these heavy flavor mesons. Within a chiral effective model, the masses of the vector and pseudoscalar charmonium (bottomonium) states are calculated from the medium modification of a dilaton field, [Formula: see text], which mimics the gluon condensates of quantum chromodynamics (QCD). The effects of the Dirac sea (DS) and the anomalous magnetic moments (AMMs) of the nucleons are taken into consideration in this study. In the presence of a magnetic field, there is mixing of the pseudoscalar (P) meson and the longitudinal component of the vector (V) meson (PV mixing), which leads to appreciable modifications of their masses. The radiative decay widths of the vector (V) heavy quarkonia to the pseudoscalar (P) mesons ([Formula: see text], [Formula: see text] and [Formula: see text] for the charm sector and [Formula: see text], [Formula: see text], for the bottom sector) in the magnetized asymmetric nuclear matter are also investigated in this work. The difference in the mass of the transverse component from the longitudinal component of the vector meson, arising due to PV mixing, is observed as a double peak structure in the invariant mass spectrum of the production cross-section of [Formula: see text]. This is observed to be appreciably more pronounced as the value of the magnetic field is increased. For the bottomonium ([Formula: see text]) production cross-section, the effect of the PV mixing effect is observed to be marginal, and there is observed to be a downward shift in the peak position due to the DS contributions. The modifications of the production cross-sections as well as the radiative decay widths of the heavy quarkonia in the magnetized matter should have observable consequences on the production of these heavy flavor mesons resulting from ultra-relativistic peripheral heavy ion collision experiments, where the created magnetic field can be extremely large.