arXiv subjects

Arvind Kumar

Publications and source records attributed to Arvind Kumar.

132 records · Page 8Linked to original sources

arXiv2010

$J/ψ$ and $η_{c}$ masses in isospin asymmetric hot nuclear matter - a QCD sum rule approach

We study the in-medium masses of the charmonium states $J/ψ$ and $η_{c}$ in the nuclear medium using QCD sum rule approach. These mass modifications arise due to modifications of the scalar and the twist-2 gluon condensates in the hot hadronic matter. The scalar gluon condensate, $<\frac{α_{s}}π G^a_{μν} {G^a}^{μν}>$ and the twist-2 tensorial gluon operator, $<\frac{α_{s}}π G^a_{μσ} {{G^a}_ν}^σ>$ in the nuclear medium are calculated from the medium modification of a scalar dilaton field introduced to incorporate trace anomaly of QCD within the chiral SU(3) model used in the present investigation. The effects of isospin asymmetry, density and temperature of the nuclear medium on the in-medium masses of the lowest charmonium states $J/ψ$ and $η_{c}$ mesons are investigated in the present work. The results of the present investigation are compared with the existing results on the masses of these states. The medium modifications of the masses of these charmonium states ($J/ψ$ and $η_c$) seem to be appreciable at high densities and should modify the experimental observables arising from the compressed baryonic matter produced in asymmetric heavy ion collision experiments at the future facility of FAIR, GSI.

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arXiv2010

D mesons and charmonium states in asymmetric nuclear matter at finite temperatures

We investigate the in-medium masses of $D$ and $\bar{D}$ mesons in the isospin-asymmetric nuclear matter at finite temperatures arising due to the interactions with the nucleons, the scalar isoscalar meson $σ$, and the scalar iso-vector meson $δ$ within a SU(4) model. The in-medium masses of $J/ψ$ and the excited charmonium states ($ψ(3686)$ and $ψ(3770)$) are also calculated in the hot isospin asymmetric nuclear matter in the present investigation. These mass modifications arise due to the interaction of the charmonium states with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within the effective chiral model. The change in the mass of $J/ψ$ in the nuclear matter with the density is seen to be rather small, as has been shown in the literature by using various approaches, whereas, the masses of the excited states of charmonium ($ψ(3686)$ and $ψ(3770)$) are seen to have considerable drop at high densities. The present study of the in-medium masses of $D$ ($\bar{D}$) mesons as well as of the charmonium states will be of relevance for the observables from the compressed baryonic matter, like the production and collective flow of the $D$ ($\bar D$) mesons, resulting from the asymmetric heavy ion collision experiments planned at the future facility of the FAIR, GSI. The mass modifications of $D$ and $\bar{D}$ mesons as well as of the charmonium states in hot nuclear medium can modify the decay of the charmonium states ($Ψ^{'}, χ_{c}, J/Ψ$) to $D\bar{D}$ pairs in the hot dense hadronic matter. The small attractive potentials observed for the $\bar{D}$ mesons may lead to formation of the $\bar{D}$ mesic nuclei.

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arXiv2010

Charmonium mass in hot asymmetric nuclear matter

We calculate the in-medium masses of J/$ψ$ and of the excited states of charmonium ($ψ$(3686) and $ψ$(3770)) in isospin asymmetric nuclear matter at finite temperatures. These mass modifications arise due to the interaction of the charmonium states with the gluon condensates of QCD, simulated by a scalar dilaton field introduced to incorporate the broken scale invariance of QCD within an effective chiral model. The change in the mass of J/$ψ$ in the nuclear matter with density is seen to be rather small, as has been shown in the literature by using various approaches, whereas, the masses of the excited states of charmonium ($ψ$(3686) and $ψ$(3770)) are seen to have considerable drop at high densities. The dependence of the masses of the charmonium states on the isospin asymmetry has also been investigated in the hot nuclear matter and is seen to be appreciable at moderate temperatures and high densities. These medium modifications of the charmonium states should modify the experimental observables arising from the compressed baryonic matter produced in asymmetric heavy ion collision experiments in the future facility of FAIR, GSI.

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arXiv2009

D mesons in asymmetric nuclear matter at finite temperatures

We study the in-medium properties of $D$ and $\bar{D}$ mesons in isospin-asymmetric nuclear matter at finite temperatures using an effective chiral SU(4) model. The interactions of $D$ and $\bar{D}$ mesons with nucleons, scalar isoscalar meson $σ$, and scalar iso-vector meson $δ$ are taken into consideration. It is found that as compared to the $\bar{D}$ mesons, the properties of the $D$ mesons are observed to be quite sensitive to the isospin-asymmetry at high densities. At finite densities, the masses of $D$ and $\bar{D}$ mesons observed at finite temperatures are seen to be higher in comparison to the zero temperature case. The present study of the in-medium properties of $D$ and $\bar{D}$ mesons will be of relevance for the experiments in the future facility of the FAIR, GSI, where the compressed baryonic matter at high densities and moderate temperatures is expected to be produced. The mass modifications of $D$ and $\bar{D}$ mesons in hot nuclear medium can lead to decay of the charmonium states ($Ψ^{'}, χ_{c}, J/Ψ$) to $D\bar{D}$ pairs in dense hadronic matter. The isospin-asymmetric effects on the properties of the open charm mesons for the doublets $D=(D^0,D^+)$ and $\bar D=(\bar D^0,D^-)$ should show in observables like their production and collective flow in asymmetric heavy-ion collisions. The small attractive potentials observed for the $\bar{D}$ mesons may also lead to formation of the $\bar{D}$ mesic nuclei.

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arXiv2009

Kaon properties in (proto)neutron stars

The modification on kaon and antikaon properties of in the interior of (proto-)neutron stars is investigated using a chiral SU(3) model. The parameters of the model are fitted to nuclear matter saturation properties, baryon octet vacuum masses, hyperon optical potentials and low energy a kaon-nucleon scattering lengths. We study the kaon/antikaon medium modification and explore the possibility of antikaon condensation in (proto-)neutron star matter at zero as well as finite temperature/entropy and neutrino content. The effect of hyperons on kaon and antikaon optical potentials is also investigated at different stages of the neutron star evolution.

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arXiv2008

Kaon and antikaon optical potentials in isospin asymmetric hyperonic matter

The medium modifications of the energies of kaons and antikaons in isospin asymmetric hyperonic matter are investigated using a chiral SU(3) model. The isospin dependent medium effects, are important for asymmetric heavy ion collision experiments, as well as relevant for the neutron star phenomenology as the bulk matter in the interior of the neutron star is highly isospin asymmetric. The effects of hyperons on the medium modifications of the kaons and antikaons in the strange hadronic matter are investigated in the present work and are seen to be appreciable for hadronic matter with large strangeness fractions. The study of the K-mesons in the asymmetric strange hadronic matter can be especially relevant for the compressed strange baryonic matter which can result from asymmetric heavy ion collision experiments in the future accelerator facility FAIR at GSI.

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