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Prasad Hegde

Publications and source records attributed to Prasad Hegde.

23 records · Page 2Linked to original sources
arXiv2011

Looking for $U(1)_A$ Restoration in Hot QCD with Domain Wall Fermions

The effects of the axial anomaly are suppressed at high temperatures due to screening effects in the quark-gluon plasma. If the suppression is nearly complete close to the chiral transition temperature, this can have consequences for the nature of the phase transition. The use of a chiral action such as Domain Wall Fermions allows us to gain a deeper insight into the issue. Our lattice sizes were $16^3\times 8\times L_s$, with $L_s=32$ or 48, and our pion mass was approximately 200 MeV. We found that $U(1)_A$ stayed broken above the chiral transition. However the breaking was found to be due to topologically nontrivial configurations which raises the question as to whether it persists in the thermodynamic limit. We also present results for the eigenvalue density of the Dirac operator. It is seen that although the density decreases dramatically across the chiral transition temperature, $U(1)_A$ still remains broken at our current volume and quark mass due to the presence of zero modes.

hep-lat↗
arXiv2011

Fluctuations and Higher Moments of Conserved Charges from the Lattice

We present results for the lowest-order non-vanishing quark number susceptibilities. These were calculated using an improved action viz. the HISQ action, which controls taste violations that are responsible for distorting the light meson spectrum. Our calculations, with a pion mass of 160 MeV, are also much closer to the physical limit than previous studies. We find a broad crossover from the hadronic to the quark regimes, although interactions remain significant even at the highest temperatures studied. Our results are also in good agreement with Hadron Resonance Gas models below the crossover temperature.

hep-lat↗
arXiv2009

Quark number fluctuations at high temperatures

We calculate the second, fourth and sixth order quark number fluctuations in the deconfined phase of 2+1 flavor QCD using lattices with temporal extent Nt=4, 6, 8 and 12. We consider light, strange and charm quarks. We use p4 action for valence quarks and gauge configurations generated with p4 action with physical value of the strange quark mass and light quark mass mq=0.1ms generated by the RBC-Bielefeld collaboration. We observe that for all quark masses the quark number fluctuations rapidly get close to the corresponding ideal gas limits. We compare our results to predictions of a quasi-particle model and resummed high temperature perturbative calculations. We also investigate correlations among different flavor channels.

hep-lat↗
arXiv2008

Calculating Quark Number Susceptibilities with Domain-Wall Fermions

We present results from calculations of different quark number and hadronic susceptibilities on 2+1-flavor dynamical domain wall ensembles. We find that the iso-spin and electric charge susceptibilities are especially well suited to determine the transition temperature, as these quantities show only small statistical errors. Moreover, the transition values of the coupling obtained from iso-spin and electrical charge susceptibilities are in good agreement with the one obtained from the chiral condensate.

hep-lat↗