Nuclear Theory·nucl-th

Wednesday·August 24, 2016

8 papers—2 primary·6 cross-listed

03
[Submitted on 22 Aug 2016] (cross-list from hep-ph)
Z(3) metastable states in Polyakov Quark Meson model
Ranjita K. Mohapatra🇮🇳 · Hiranmaya Mishra🇮🇳
We study the existence of Z(3) metastable states in the presence of the dynamical quarks within the ambit of Polyakov quark meson (PQM) model. Within the parameters of the model, it is seen that for temperatures $T_{m}$ greater than the chiral transition temperature $T_{c}$ , Z(3) metastable states exist ( $T_{m} \sim 310$ MeV at zero chemical potential). At finite chemical potential $T_{m}$ is larger than the same at vanishing chemical potential. We also observe a shift of ( $\sim 5^{\circ}$ ) in the phase of the metastable vacua at zero chemical potential. The energy density difference between true and Z(3) metastable vacua is very large in this model. This indicates a strong explicit symmetry breaking effect due to quarks in PQM model. We compare this explicit symmetry breaking in PQM model with small explicit symmetry breaking as a linear term in Polyakov loop added to the Polyakov loop potential. We also study about the possibility of domain growth in a quenched transition to QGP in relativistic heavy ion collisions.
Comments:
16 pages, 11 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1608.06139 [pdf]
PRD(2017)·7 citations
04
[Submitted on 23 Aug 2016] (cross-list from astro-ph.HE)
Equation of state for neutron star matter with NJL model and Dirac-Brueckner-Hartree-Fock approximation
Takahide Kambe🇯🇵 · Tetsuya Katayama🇯🇵 · Koichi Saito🇯🇵
As the interior density of a neutron star can become very high, it has been expected and discussed that quark matter may exist inside it. To describe the transition from hadron to quark phases (and vice versa), there are mainly two methods; one is the first-order phase transition, and the other is the crossover phenomenon. In the present study, using the flavor-SU (3) NJL model with the vector coupling interaction, we have calculated the equation of state for the quark phase at high density. Furthermore, for the hadron phase at low density, we have used two kinds of the equations of state; one is a relatively soft one by the QHD model, and the other is a stiff one calculated with relativistic Brueckner-Hartree-Fock approximation. Using those equations of state for the two phases, we have investigated the influence of various choices of parameters concerning the crossover region on the mass and radius of a neutron star.
Comments:
3 pages, 2 figures, conference proceedings: NIC Symposium, 19-24 June 2016, Niigata, Japan
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1608.06449 [pdf]
JPS Conf.Proc.(2017)·4 citations
05
[Submitted on 23 Aug 2016] (cross-list from hep-ph)
Hadronic Lorentz Violation in Chiral Perturbation Theory
Rasha Kamand🇺🇸 · Brett Altschul🇺🇸 · Matthias R. Schindler🇺🇸
Any possible Lorentz violation in the hadron sector must be tied to Lorentz violation at the underlying quark level. The relationships between the theories at these two levels are studied using chiral perturbation theory. Starting from a two-flavor quark theory that includes dimension-four Lorentz-violation operators, the effective Lagrangians are derived for both pions and nucleons, with novel terms appearing in both sectors. Since the Lorentz violation coefficients for nucleons and pions are all related to a single set of underlying quark coefficients, it is possible to place approximate bounds on pion Lorentz violation using only proton and neutron observations. The resulting bounds on four pion parameters are at the $1 0^{- 23}$ level, representing improvements of ten orders of magnitude.
Comments:
15 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1608.06503 [pdf]
PRD(2017)·27 citations
06
[Submitted on 23 Aug 2016] (cross-list from hep-ph)
Heavy Exotic Molecules with Charm and Bottom
Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸
We revisit the formation of pion-mediated heavy-light exotic molecules with both charm and bottom and their chiral partners under the general strictures of both heavy-quark and chiral symmetry. The chiral exotic partners with good parity formed using the $(0^{+}, 1^{+})$ multiplet are about twice more bound than their primary exotic partners formed using the $(0^{-}, 1^{-})$ multiplet. The chiral couplings across the multiplets $(0^{\pm}, 1^{\pm})$ cause the chiral exotic partners to unbind, and the primary exotic molecules to be about twice more bound, for $J \leq 1$ . Our multi-channel coupling results show that only the charm isosinglet exotic molecules with $J^{P C} = 1^{++}$ binds, which we identify as the reported neutral $X (3872)$ . Also, the bottom isotriplet exotic with $J^{P C} = 1^{+-}$ binds, which we identify as a mixture of the reported charged exotics $Z_{b}^{+} (10610)$ and $Z_{b}^{+} (10650)$ . The bound isosinglet with $J^{P C} = 1^{++}$ is suggested as a possible neutral $X_{b} (10532)$ not yet reported.
Comments:
10 pages, 9 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1608.06535 [pdf]
PLB(2016)·25 citations
07
[Submitted on 23 Aug 2016] (cross-list from hep-ph)
Dynamical generation of hadronic resonances in effective models with derivative interactions
Thomas Wolkanowski🇩🇪
Light scalar mesons can be understood as dynamically generated resonances. They arise as 'companion poles' in the propagators of quark-antiquark seed states when accounting for hadronic loop contributions to the self-energies of the latter. Such a mechanism may explain the overpopulation in the scalar sector - there exist more resonances with total spin $J = 0$ than can be described within a quark model. Along this line, we study an effective Lagrangian approach where the isovector state $a_{0} (1450)$ couples via both non-derivative and derivative interactions to pseudoscalar mesons. It is demonstrated that the propagator has two poles: a companion pole corresponding to $a_{0} (980)$ and a pole of the seed state $a_{0} (1450)$ . The positions of these poles are in quantitative agreement with experimental data. Besides that, we investigate similar models for the isodoublet state $K_{0}^{*} (1430)$ by performing a fit to $π K$ phase shift data in the $I = 1/2,$ $J = 0$ channel. We show that, in order to fit the data accurately, a companion pole for the $K_{0}^{*} (800)$ , that is, the light $κ$ , is required. A large- $N_{c}$ study confirms that both resonances below $1$ GeV are predominantly four-quark states, while the heavy states are quarkonia.
Comments:
151 pages, 25 figures, 8 tables, PhD thesis
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1608.06569 [pdf]
2 citations
08
[Submitted on 23 Aug 2016] (cross-list from physics.comp-ph)
Massively parallel simulations of relativistic fluid dynamics on graphics processing units with CUDA
Dennis Bazow🇺🇸 · Ulrich W. Heinz🇺🇸 · Michael Strickland🇺🇸
Relativistic fluid dynamics is a major component in dynamical simulations of the quark-gluon plasma created in relativistic heavy-ion collisions. Simulations of the full three-dimensional dissipative dynamics of the quark-gluon plasma with fluctuating initial conditions are computationally expensive and typically require some degree of parallelization. In this paper, we present a GPU implementation of the Kurganov-Tadmor algorithm which solves the 3+1d relativistic viscous hydrodynamics equations including the effects of both bulk and shear viscosities. We demonstrate that the resulting CUDA-based GPU code is approximately two orders of magnitude faster than the corresponding serial implementation of the Kurganov-Tadmor algorithm. We validate the code using (semi-)analytic tests such as the relativistic shock-tube and Gubser flow.
Comments:
57 pages, 18 figures
Subjects:
Computational Physics (physics.comp-ph); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1608.06577 [pdf]
Comput.Phys.Commun.(2018)·38 citations

Affiliations

first authorsco-authorsvia INSPIRE

Z(3) metastable states in Polyakov Quark Meson model

Equation of state for neutron star matter with NJL model and Dirac-Brueckner-Hartree-Fock approximation

Hadronic Lorentz Violation in Chiral Perturbation Theory

Heavy Exotic Molecules with Charm and Bottom

Dynamical generation of hadronic resonances in effective models with derivative interactions

Massively parallel simulations of relativistic fluid dynamics on graphics processing units with CUDA

Affiliations