Nuclear Theory·nucl-th

Tuesday·July 16, 2019

12 papers—4 primary·8 cross-listed

01
[Submitted on 13 Jul 2019]
Finite volume effects on quarkonium dissociation temperature in an impenetrable QGP sphere
Peng Cheng🇨🇳 · Xiaofeng Luo🇨🇳 · Jialun Ping🇨🇳 · Hongshi Zong🇨🇳
The system of a quarkonium confined by an impenetrable spherical cavity filled with a hot quantum chromodynamics (QCD) medium is studied by solving the Schrödinger equation. This is the first time this issue has been raised for discussion. The Schrödinger equation with an appropriate boundary condition of a quarkonium in an impenetrable cavity filled with a hot medium is derived. The numerical results are obtained with the help of Gaussian Expansion Method. Binding energies and radii of the ground and low-excited states are obtained as a function of the medium temperature and the cavity radius. We find the behaviour of quarkonium in this cavity is different from that in infinite space. Our results show that the quarkonium dissociation temperature decreases as the cavity radius decreases and the finite volume effects on the ground state are more obvious than on the excited states. We also find that the less mass of the constituents and the bigger radius of the quarkonium lead the finite volume effects to become more obvious.
Comments:
9 pages, 16 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1907.05978 [pdf]
PRD(2019)·3 citations
02
[Submitted on 15 Jul 2019]
Double charge-exchange phonon states
X. Roca-Maza · H. Sagawa · G. Colo'
We study double charge-exchange phonon states in neutron-rich nuclei, in particular the double isobaric analog states and the double Gamow-Teller excitations, induced by the double isospin operator $\sum_{i, j = 1}^{A} t_{-} (i) t_{-} (j)$ and spin-isospin operator $\sum_{i, j = 1}^{A} σ (i) t_{-} (i) σ (j) t_{-} (j)$ , respectively. We employ quartic commutator relations to evaluate the average energies $E_{DIAS} - 2 E_{IAS}$ and $E_{DGTR} - E_{DIAS} - 2 (E_{GTR} - E_{IAS})$ , and conventional double commutator relations to evaluate the average energies of $E_{GTR} - E_{IAS}$ and $E_{IAS}$ . We have found that the corrections due to quartic commutators follow the approximate laws: $E_{DIAS} - 2 E_{IAS} \approx \frac{3}{2} A^{- 1/3}$ MeV and $E_{DGTR} - E_{DIAS} - 2 (E_{GTR} - E_{IAS}) \approx 16 A^{- 1}$ MeV. While the former is dominated by direct Coulomb effects, since Coulomb exchange cancels out to some extent with isospin symmetry breaking contributions originated form the nuclear strong force, the latter is sensitive to the difference in strength between the spin and spin-isospin chanels of the strong interaction.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1907.06368 [pdf]
PRC(2020)·11 citations
03
[Submitted on 10 Jul 2019]
Phases of Hadron-Quark Matter in (Proto) Neutron Stars
F. Weber (1 and 2) · D. Farrell (1) · W. M. Spinella (3) · G. Malfatti (4 and 5) · M. G. Orsaria (4 and 5) · G. A. Contrera (4 and 6) · I. Maloney (1) ((1) San Diego State University, (2) University of California at San Diego, (3) Wentworth Institute of Technology, (4) National University of La Plata, (5) CONICET (National Scientific and Technical Research Council, Argentina))
In the first part of this paper, we investigate the possible existence of a structured hadron-quark mixed phase in the cores of neutron stars. This phase, referred to as the hadron-quark pasta phase, consists of spherical blob, rod, and slab rare phase geometries. Particular emphasis is given to modeling the size othis phase in rotating neutron stars. We use the relativistic mean-field theory to model hadronic matter and the non-local three-flavor Nambu-Jona-Lasinio model to describe quark matter. Based on these models, the hadron-quark pasta phase exists only in very massive neutron stars, whose rotational frequencies are less than around 300 Hz. All other stars are not dense enough to trigger quark deconfinement in their cores. Part two of the paper deals with the quark-hadron composition of hot (proto) neutron star matter. To this end we use a local three-flavor Polyakov-Nambu-Jona-Lasinio model which includes the 't Hooft (quark flavor mixing) term. It is found that this term leads to non-negligible changes in the particle composition of (proto) neutron stars made of hadron-quark matter.
Comments:
Paper presented at the conference "Compact Stars in the QCD Phase Diagram VII", 11 - 15 June 2018, CUNY Advanced Science Research Center, New York, USA. To appear in the special issue "Compact Stars in the QCD Phase Diagram and in the Multi-Messenger Era of Astronomy" of the journal Universe
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
1907.06591 [pdf]
Universe(2019)·18 citations
04
[Submitted on 5 Jul 2019]
Hot quark matter and (proto-) neutron stars
G. Malfatti🇦🇷 · M. Orsaria🇦🇷 · G. A. Contrera🇦🇷 · F. Weber🇺🇸 · I. F. Ranea-Sandoval🇦🇷
In part one of this paper, we use a non-local extension of the 3-flavor Polyakov-Nambu-Jona-Lasinio model, which takes into account flavor-mixing, momentum dependent quark masses, and vector interactions among quarks, to investigate the possible existence of a spinodal region (determined by the vanishing of the speed of sound) in the QCD phase diagram and determine the temperature and chemical potential of the critical end point. In part two of the paper, we investigate the quark-hadron composition of baryonic matter at zero as well as non-zero temperature. This is of great topical interest for the analysis and interpretation of neutron star merger events such as GW170817. With this in mind, we determine the composition of proto-neutron star matter for entropies and lepton fractions that are typical of such matter. These compositions are used to delineate the evolution of proto-neutron stars to neutron stars in the baryon-mass versus gravitational-mass diagram. The hot stellar models turn out to contain significant fractions of hyperons and $Δ$ -isobars but no deconfined quarks. The latter, are found to exist only in cold neutron stars.
Comments:
27 pages, 17 figures. Accepted for publication in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); physics.space-ph (physics.space-ph)
arXiv:
1907.06597 [pdf]
PRC(2019)·60 citations

Affiliations

first authorsco-authorsvia INSPIRE

Finite volume effects on quarkonium dissociation temperature in an impenetrable QGP sphere

Double charge-exchange phonon states

Phases of Hadron-Quark Matter in (Proto) Neutron Stars

Hot quark matter and (proto-) neutron stars

Affiliations