Nuclear Theory·nucl-th

Tuesday·February 26, 2019

18 papers—10 primary·8 cross-listed

11
Flow and vorticity with varying chemical potential in relativistic heavy ion collisions
Abhisek Saha🇮🇳 · Soma Sanyal🇮🇳
We study the vorticity patterns in relativistic heavy ion collisions with respect to the collision energy. The collision energy is related to the chemical potential used in the thermal - statistical models that assume approximate chemical equilibrium after the relativistic collision. We use the multiphase transport model (AMPT) to study the vorticity in the initial parton phase as well as the final hadronic phase of the relativistic heavy ion collision. We find that as the chemical potential increases,the vortices are larger in size. Using different definitions of vorticity, we find that vorticity plays a greater role at lower collision energies than at higher collision energies. We also look at other effects of the flow patterns related to the bulk viscosity and the shear viscosity at different collision energies. We find that the shear viscosity obtained is almost a constant with a small decrease at higher collision energies. We also look at the elliptic flow as it is related to viscous effects in the final stages after the collision. Our results indicate that viscosity plays a greater role at higher chemical potential and lower collision energies.
↳ hep-phnucl-thIJMPE(2020)·7 citations
12
Octet baryon electromagnetic form factor double ratios $(G_{E}^{*} / G_{M}^{*}) / (G_{E} / G_{M})$ in a nuclear medium
G. Ramalho🇧🇷 · J.P.B.C. de Melo🇧🇷 · K. Tsushima🇧🇷
The ratios of the baryon electric ( $G_{E}$ ) to magnetic ( $G_{M}$ ) form factors, $G_{E} / G_{M}$ , can provide us with important information on the structure of baryons in vacuum as demonstrated in recent studies for the proton and neutron systems. It has been argued that the corresponding in-medium ratios, $G_{E}^{*} / G_{M}^{*}$ , can also provide useful information on the electromagnetic structure of baryons in a nuclear medium. Although the ratios may not be measured directly in experiments except for the proton at present, the double ratios $(G_{E}^{*} / G_{M}^{*}) / (G_{E} / G_{M})$ can be directly related to the polarization-transfer measurements of bound baryons. In the present work we estimate, for the first time, the double ratios $(G_{E}^{*} / G_{M}^{*}) / (G_{E} / G_{M})$ for all the members of octet baryons in symmetric nuclear matter in the range $Q^{2} = 0$ --3 GeV $^{2}$ , where $Q^{2} = - q^{2}$ with $q$ being the four-momentum transfer.
↳ hep-phhep-exnucl-exnucl-thPRD(2019)·16 citations
13
Studies on photo- and electro-productions of $Λ (1405)$ via $γ^{(*)} p \to K^{*+} π^{0} Σ^{0}$
Seung-il Nam🇰🇷 · Atsushi Hosaka🇯🇵
We study the photo- and electro-productions of the vector kaon off the proton, i.e., $γ^{(*)} p \to K^{*+} π^{0} Σ^{0}$ , and investigate the line shape of the $π^{0} Σ^{0}$ invariant mass in an effective Lagrangian approach with the inclusion of a $K^{*} N Λ^{*}$ interaction. Relevant electromagnetic form factors for the neutral hyperons and charged strange mesons are constructed by considering experimental and theoretical information. We find that the $Λ^{*}$ peak is clearly observed for the photo- and electro-productions with the finite $K^{*} N Λ^{*}$ interaction, whereas the clear peak signals survive only for the electro-production, when we ignore the interaction. These different behaviors can be understood by different $Q^{2}$ dependences in the $K^{*}$ electromagnetic and $K^{*} \to γ K$ transition form factors. We suggest a photon-polarization asymmetry $Σ$ to extract information of the $K^{*} N Λ^{*}$ interaction. It turns out that $Σ$ near the $Λ^{*}$ peak region becomes negative with a finite $K^{*} N Λ^{*}$ interaction while positive without it for $Q^{2} = 0$ , due to the different naturalities of $K$ and $K^{*}$ exchanges. For $Q^{2} \neq = 0$ , we observe more obvious signals in the peak region due to the additional contribution of the longitudinal virtual photon for $Λ^{*}$ .
↳ hep-phhep-exnucl-exnucl-thPRC(2019)·0 citations
14
Anomaly-induced transport phenomena from the imaginary-time formalism
Masaru Hongo🇯🇵 · Yoshimasa Hidaka🇯🇵
A derivation of the anomaly-induced transport phenomena---the chiral magnetic/vortical effect---is revisited based on the imaginary-time formalism of quantum field theory. Considering the simplest anomalous system composed of a single Weyl fermion, we provide two derivations: perturbative (one-loop) evaluation of the anomalous transport coefficient, and the anomaly matching for the local thermodynamic functional.
↳ hep-thcond-mat.mes-hallcond-mat.stat-mechhep-ph+1Particles(2019)·13 citations
15
Fluctuations and correlations in thermal QCD
E. Megias🇪🇸 · E. Ruiz Arriola🇪🇸 · L.L. Salcedo🇪🇸
We study the equation of state, fluctuations and static correlators of electric charge, baryon number and strangeness, by considering a realization of the Hadron Resonance Gas model in the light flavor sector of QCD. We emphasize the importance of these observables to study, within this approach, the possible existence of exotic and missing states in the hadron spectrum. Some preliminary results for the baryon spectrum have been obtained within a relativistic quark-diquark model, leading to an overall good agreement with the spectrum obtained with other quark models. Finally, it is conjectured, within the Hadron Resonance Gas approach, the existence of a singularity in the correlators at zero temperature, which turns out to be analogous to the divergence of the partition function at the Hagedorn temperature.
↳ hep-phhep-latnucl-thNucl.Part.Phys.Proc.(2018)·1 citation
16
Progress in Multibaryon Spectroscopy
Evan Berkowitz🇩🇪 · David Brantley🇺🇸 · Kenneth McElvain🇺🇸 · André Walker-Loud🇺🇸 · Chia Cheng Chang🇯🇵 · M.A. Clark🇺🇸 · Thorsten Kurth🇺🇸 · Bálint Joó🇺🇸 · Henry Monge-Camacho🇺🇸 · Amy Nicholson🇺🇸 · Enrico Rinaldi🇺🇸 · Pavlos Vranas🇺🇸
Anchoring the nuclear interaction in QCD is a long-outstanding problem in nuclear physics. While the lattice community has made enormous progress in mesonic physics and single nucleon physics, continuum-limit physical-point multi-nucleon physics has remained out of reach. I will review CalLat's strategy for multi-nucleon spectroscopy and our latest results.
↳ hep-latnucl-thPoS(2018)·7 citations
17
Third-order momentum correlation interferometry maps for entangled quantal states of three singly trapped massive ultracold fermions
Constantine Yannouleas · Uzi Landman
Analytic higher-order momentum correlation functions associated with the time-of-flight spectroscopy of three ultracold fermionic atoms singly-confined in a linear three-well optical trap are presented, corresponding to the W- and Greenberger-Horne-Zeilinger-type (GHZ) states that belong to characteristic classes of tripartite entanglement and represent the strong-interaction regime captured by a three-site Heisenberg Hamiltonian. The methodology introduced here contrasts with and goes beyond that based on the standard Wick's factorization scheme; it enables determination of both third-order and second-order spin-resolved and spin-unresolved momentum correlations, aiming at matter-wave interference investigations with trapped massive particles in analogy with, and having the potential for expanding the scope of, recent three-photon quantum-optics interferometry.
↳ cond-mat.quant-gasnucl-thquant-phPRA(2019)·3 citations
18
Ultrahigh-energy cosmic rays: Anomalies, QCD, and LHC data
David d'Enterria🇨🇭
Measurements of proton and nuclear collisions at the Large Hadron Collider at nucleon-nucleon c.m. energies up to $s_{N N} =$ 13 TeV, have improved our understanding of hadronic interactions at the highest energies reached in collisions of cosmic rays with nuclei in the earth atmosphere, up to $s_{N N} \approx 450$ TeV. The Monte Carlo event generators (EPOS, QGSJET, and SIBYLL) commonly used to describe the air showers generated by ultrahigh-energy cosmic rays (UHECR, with $E_{C R} \approx 1 0^{17}$ -- $1 0^{20}$ eV) feature now, after parameter retuning based on LHC Run-I data, more consistent predictions on the nature of the cosmic rays at the tail of the measured spectrum. However, anomalies persist in the data that cannot be accommodated by the models. Among others, the total number of muons (as well as their maximum production depth) remains significantly underestimated (overestimated) by all models. Comparisons of EPOS, QGSJET, and SIBYLL predictions to the latest LHC data, and to collider MC generators such as PYTHIA, indicate that improved description of hard multiple minijet production and nuclear effects may help reduce part of the data--model discrepancies, shed light on the UHECR composition approaching the observed $E_{C R} \approx 1 0^{20}$ eV cutoff, and uncover any potential new physics responsible of the observed anomalies.
↳ astro-ph.HEhep-exhep-phnucl-ex+1EPJ Web Conf.(2019)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE

Tuesday·February 26, 2019

Flow and vorticity with varying chemical potential in relativistic heavy ion collisions

Octet baryon electromagnetic form factor double ratios $(G_{E}^{} / G_{M}^{}) / (G_{E} / G_{M})$ in a nuclear medium

Studies on photo- and electro-productions of $Λ (1405)$ via $γ^{()} p \to K^{+} π^{0} Σ^{0}$

Anomaly-induced transport phenomena from the imaginary-time formalism

Fluctuations and correlations in thermal QCD

Progress in Multibaryon Spectroscopy

Third-order momentum correlation interferometry maps for entangled quantal states of three singly trapped massive ultracold fermions

Ultrahigh-energy cosmic rays: Anomalies, QCD, and LHC data

Affiliations