Seebeck effect in a thermal QCD medium in the presence of strong magnetic field (original) (raw)
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arXiv (Cornell University), 2020
Our first aim is to explore the effect of the collision integral with the insurance of instantaneous conservation of particle number on the charge and heat transport in a thermal QCD medium. The second aim is to see how the dimensional reduction due to strong magnetic field modulates the transport through the entangled effects such as the collision-time and occupation probability etc. in the collision integral. Final aim is to check how the quasiparticle description of partons, through the dispersion relation of thermal QCD in strong magnetic field, alters the aforesaid conclusions. We observe that the modified collision term expedites both transport, which is manifested by the larger magnitudes of electrical (σ el) and thermal (κ) conductivities, in comparison to the relaxation collision term. As a corollary, the Lorenz number is dominated by the later and the Knudsen number is by the former. However, the strong magnetic field not only flips the dominance of collision term in the heat transport, it also causes drastic enhancement of both σ el and κ and reduction in the specific heat. As a result, the equilibration factor, the Knudsen number becomes much larger than one, which defies physical interpretation. Finally, the quasiparticle description of partons in the absence of strong magnetic field impedes the transport of charge and heat, resulting in tiny decrease of the conductivities. However, the strong magnetic field does noticeable observations: the conductivities now gets reduced to the physically plausible values, the temperature dependence of σ el gets reversed, i.e. it now decreases with temperature, effect of collision integral gets smeared in κ etc. The Knudsen number thus becomes much smaller than one, implying that the system be remained in equilibrium. These findings attribute to the fact that the collective oscillation in the dispersion relation of thermal QCD in strong magnetic field sets in much larger scale, manifested by the large in-medium flavour masses.
Seebeck effect in a weakly magnetized thermal QCD medium
2021
We estimate the thermoelectric response, namely, the Seebeck coefficient of a hot and deconfined plasma of quarks and gluons, created post ultrarelativistic heavy ion collisions in the presence of a weak, homogeneous background magnetic field. We employ the kinetic theory framework, wherein we use the relativistic Boltzmann transport equation in the relaxation time approximation. In-medium interactions are taken into account via the quasiparticle masses of the partons extracted from one loop perturbative thermal QCD. We calculate the individual Seebeck coefficients of the quark species from which we show that the Seebeck coefficient of the medium can be obtained as a weighted average. Both the individual and total Seebeck coefficients are seen to decrease with temperature and increase with the chemical potential. We find that a larger current quark mass has an amplifying effect on the individual Seebeck coefficient in the presence of a weak magnetic field. We also draw comparisons o...
Lecture Notes in Physics, 2004
At the chiral restoration/deconfinement transition, most hadrons undergo a Mott transition from being bound states in the confined phase to resonances in the deconfined phase. We investigate the consequences of this qualitative change in the hadron spectrum on final state interactions of charmonium in hot and dense matter, and show that the Mott effect for D-mesons leads to a critical enhancement of the J/ψ dissociation rate. Anomalous J/ψ suppression in the NA50 experiment is discussed as well as the role of the Mott effect for the heavy flavor kinetics in future experiments at the LHC. The status of our calculations of heavy quarkonium dissociation cross sections due to quark and gluon impact is reviewed, and estimates for in-medium effects due to the lowering of the ionisation threshold are given.
Heavy-light quark pseudoscalar and vector mesons at finite temperature
Journal of High Energy Physics, 2007
The temperature dependence of the mass, leptonic decay constant, and width of heavy-light quark peseudoscalar and vector mesons is obtained in the framework of thermal Hilbert moment QCD sum rules. The leptonic decay constants of both pseudoscalar and vector mesons decrease with increasing TTT, and vanish at a critical temperature TcT_cTc, while the mesons develop a width which increases dramatically and diverges at TcT_cTc, where TcT_cTc is the temperature for chiral-symmetry restoration. These results indicate the disappearance of hadrons from the spectral function, which then becomes a smooth function of the energy. This is interpreted as a signal for deconfinement at T=TcT=T_cT=Tc. In contrast, the masses show little dependence on the temperature, except very close to TcT_cTc, where the pseudoscalar meson mass increases slightly by 10-20 %, and the vector meson mass decreases by some 20-30 %
Magnetic field-induced anisotropic interaction in heavy quark bound states
arXiv: High Energy Physics - Phenomenology, 2020
We have investigated how a strong magnetic field (B) could decipher the anisotropic interaction in heavy quark ($Q$) and antiquark ($\bar Q$) bound states through the perturbative thermal QCD in real-time formalism. So we thermalize Schwinger propagator for quarks in LLL and the Feynman propagator for gluons to calculate the gluon self-energy. For the quark-loop contribution to the self-energy, the medium does not have any temperature correction and the vacuum term gives rise an anisotropic term whereas the gluon-loop yields temperature correction. This finding in quark-loop contribution corroborates the equivalence of a massless QED in (1+1)-dimension with the massless thermal QCD in strong B, which (quark sector) is reduced to (1+1)-dimension (longitudinal). Thus the permittivity of the medium behaves like as a tensor. Thus the permittivity of medium makes the QbarQQ \bar QQbarQ potential anisotropic, which resembles with a contemporary results found in lattice studies. As a result, poten...
Dynamics of open heavy flavour in a weakly magnetized thermal QCD medium
arXiv (Cornell University), 2023
We calculate the momentum diffusion coefficients and energy loss of a heavy quark (HQ) traversing through the quark-gluon plasma in the presence of a weak magnetic field, upto leading order in the strong coupling αs. t channel Coulomb scatterings of the HQ with the thermal quarks and gluons are considered, whereas Compton scatterings and gluon radiation are neglected. The scale hierarchy considered in this work is MQ ≫ T ≫ eB/T. The calculations are carried out ina perturbative framework where the interaction rate Γ is calculated from the imaginary part of the HQ self energy. We find that the longitudinal and transverse momentum diffusion coefficients of the HQ decrease with temperature, whereas the energy loss increases with temperature. Variation with both the temperature and magnetic field is amplified for the Charm quark in comparison to bottom quark, due to the lighter mass of the former. We also find that the extent of anisotropy in the momentum diffusion coefficient depends strongly on the current mass of the HQ, with a lighter mass leading to a greater anisotropy.
REVIEW OF HEAVY QUARK PHYSICS – THEORY
International Journal of Modern Physics A, 2005
Recent progress in the theory of B-meson decays is reviewed with emphasis on the aspects related to the B-factory data.
Finite-temperature corrections in the dilated chiral quark model
Physical Review C, 1995
\simeq \frac{m_{\sigma}(T)}{m_{\sigma}}$ while we argue, using PCAC, that pion mass does not scale within the temperature range involved in our Lagrangian. It is found that the hadron masses and the pion decay constant drop faster with temperature in the dilated chiral quark model than in the conventional linear sigma model that does not take into account the QCD scale anomaly. We attribute the difference in scaling in heat bath to the effect of baryonic medium on thermal properties of the hadrons. Our finding would imply that the AGS experiments (dense {\it and} hot matter) and the RHIC experiments (hot and dilute matter) will ``see" different hadron properties in the hadronization phase.
Dissociation of heavy quarkonia in an anisotropic hot QCD medium in a quasiparticle model
Physical Review D
The present article is the follow-up work of Phys. Rev. D 94, 094006 (2016), where we have extended the study of quarkonia dissociation in (momentum) anisotropic hot QCD medium. As evident by the experimentally observed collective flow at the RHIC and LHC, the momentum anisotropy is present at almost all the stages after the collision, and therefore, it is important to include its effects in the analysis. Employing the in-medium (corrected) potential while considering the anisotropy (both oblate and prolate cases) in the medium, the thermal widths and the binding energies of the heavy quarkonia states (s-wave charmonia and s-wave bottomonia specifically, for radial quantum numbers n ¼ 1 and 2) have been determined. The hot QCD medium effects have been included by employing a quasiparticle description. The presence of anisotropy has modified the potential and then the thermal widths and binding energies of these states in a significant manner. The results show a quite visible shift in the values of dissociation temperatures as compared to the isotropic case. Further, the hot QCD medium interaction effects suppress the dissociation temperature as compared to the case where we consider the medium as a noninteracting ultrarelativistic gas of quarks (antiquarks) and gluons.