Nuclear Theory·nucl-th

Tuesday·March 12, 2019

13 papers—6 primary·7 cross-listed

07
[Submitted on 9 Mar 2019] (cross-list from physics.atom-ph)
Dimensional effects in Efimov physics
M.T. Yamashita
Efimov physics is drastically affected by the change of spatial dimensions. Efimov states occur in a tridimensional (3D) environment, but disappear in two (2D) and one (1D) dimensions. In this paper, dedicated to the memory of Prof. Faddeev, we will review some recent theoretical advances related to the effect of dimensionality in the Efimov phenomenon considering three-boson systems interacting by a zero-range potential. We will start with a very ideal case with no physical scales, passing to a system with finite energies in the Born-Oppenheimer (BO) approximation and finishing with a general system. The physical reason for the appearance of the Efimov effect is given essentially by two reasons which can be revealed by the BO approximation - the form of the effective potential is proportional to $1/ R^{2}$ ( $R$ is the relative distance between the heavy particles) and its strength is smaller than the critical value given by $- (D - 2)^{2} /4$ , where $D$ is the effective dimension.
Subjects:
Atomic Physics (physics.atom-ph); Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
1903.03716 [pdf]
Few Body Syst.(2019)·2 citations
08
[Submitted on 9 Mar 2019] (cross-list from hep-ph)
Spectroscopic Assignments of the Excited $B$ -Mesons
Stephen Godfrey🇨🇦 · Kenneth Moats🇨🇦
Excited $B$ -mesons have been observed by the D0, CDF, LHCb and CMS experiments. We use the predictions of the relativized quark model to make quark model spectroscopic assignments for these states. We identify the $B_{2}^{*} (5747)$ and $B_{1} (5721)$ as the $B_{2}^{*} [1^{3} P_{2}]$ and $B_{1} [1 P_{1}]$ states and the $B_{s 2}^{*} (5840)$ and $B_{s 1} (5830)$ as the $B_{s 2}^{*} [1^{3} P_{2}]$ and $B_{s 1} [1 P_{1}]$ states. More information is needed to identify the $B_{J} (5970)$ and $B_{J} (5840)$ states and we suggest a number of measurements to make this identification: the determination of their $J^{P}$ quantum numbers and either confirming or ruling out their decays to the $B π$ final state. With the current information available we believe it most likely that the $B_{J} (5970)$ is the $B^{*} [2^{3} S_{1}]$ state, with the $B_{J} (5840)$ needing confirmation.
Comments:
7 pages, 5 tables, expt error for B_2^* decay ratio corrected, some minor word edits
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1903.03886 [pdf]
EPJA(2019)·9 citations
09
[Submitted on 10 Mar 2019] (cross-list from hep-ph)
Electrical conductivity and Hall conductivity of hot and dense hadron gas in a magnetic field: a relaxation time approach
Arpan Das🇮🇳 · Hiranmaya Mishra🇮🇳 · Ranjita K. Mohapatra🇮🇳
We estimate the electrical conductivity and the Hall conductivity of hot and dense hadron gas using the relaxation time approximation of the Boltzmann transport equation in the presence of electromagnetic field. We have investigated the temperature and the baryon chemical potential dependence of these transport coefficients in presence of magnetic field. The explicit calculation is performed within the ambit of the hadron resonance gas model. We find that the electrical conductivity decreases in the presence of magnetic field. The Hall conductivity on the other hand shows a non monotonic behavior with respect to the dependence on magnetic field. We argue that for a pair plasma (particle-anti particle plasma) where $μ_{B} = 0$ , Hall conductivity vanishes. Only for non vanishing baryon chemical potential Hall conductivity has non zero value. We also estimate the electrical conductivity and the Hall conductivity as a function of the center of mass energy along the freeze out curve as may be relevant for relativistic heavy ion collision experiments.
Comments:
15 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1903.03938 [pdf]
PRD(2019)·51 citations
10
[Submitted on 10 Mar 2019] (cross-list from hep-ph)
Multiparticle production and initial quasi-temperature from proton induced carbon collisions at $p_{L ab} = 31$ GeV/ $c$
Pei-Pin Yang🇨🇳 · Mai-Ying Duan🇨🇳 · Fu-Hu Liu🇨🇳 · Raghunath Sahoo🇮🇳
The momentum spectra of charged pions ( $π^{+}$ and $π^{-}$ ) and kaons ( $K^{+}$ and $K^{-}$ ), as well as protons ( $p$ ), produced in the beam protons induced collisions in a 90-cm-long graphite target [proton-carbon ( $p$ -C) collisions] at the beam momentum $p_{L ab} = 31$ GeV/ $c$ are studied in the framework of a multisource thermal model by using Boltzmann distribution and Monte Carlo method. The theoretical model results are approximately in agreement with the experimental data measured by the NA61/SHINE Collaboration. The related free parameters (effective temperature, rapidity shifts, and fraction of non-leading protons) and derived quantities (average transverse momentum and initial quasi-temperature) under given experimental conditions are obtained. It is shown that the considered free parameters and derived quantities to be strongly dependent on emission angle over a range from 0 to 380 mrad and weakly dependent on longitudinal position (graphite target thickness) over a range from 0 to 90 cm.
Comments:
22 pages, 16 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1903.04008 [pdf]
Adv.High Energy Phys.(2020)·2 citations
11
[Submitted on 11 Mar 2019] (cross-list from hep-th)
Localized rainbows in the QCD phase diagram
Jan Maelger🇫🇷 · Urko Reinosa🇫🇷 · Julien Serreau🇫🇷
We study the phase diagram of strongly interacting matter with light quarks using a recently proposed, small parameter approach to infrared QCD in the Landau gauge. This is based on an expansion with respect to both the inverse number of colors and the pure Yang-Mills coupling in the presence of a Curci-Ferrari mass term. At leading order, this leads to the well-known rainbow equation for the quark propagator with a massive gluon propagator. We solve the latter at nonzero temperature and chemical potential using a simple semi-analytic approximation known to capture the essence of chiral symmetry breaking in the vacuum. In the chiral limit, we find a tricritical point which becomes a critical endpoint in the presence of a nonzero bare quark mass, in agreement with the results of nonperturbative functional methods and model calculations. This supports the view that the present approach allows for a systematic study of the QCD phase diagram in a controlled expansion scheme.
Comments:
14 pages, 8 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1903.04184 [pdf]
PRD(2020)·21 citations
12
[Submitted on 11 Mar 2019] (cross-list from hep-ph)
Doubly Heavy Baryons Expanded in $1/ m_{Q}$
Takayuki Matsuki🇯🇵
Starting from the semirelativistic Hamiltonian for a doubly heavy baryon system ( $QQq$ ) with Coulomb and linear confining scalar potentials, and operating the naive Foldy-Wouthuysen-Tani transformation on two heavy quarks, I construct a formulation how to calculate mass spectra and wave functions of doubly heavy baryons. Based on our formulation, their masses and wave functions are expanded in $1/ m_{Q}$ with a heavy quark mass $m_{Q}$ and the $λ$ mode lowest-order equation is examined carefully to obtain a complete set of eigenfunctions. I claim that the $ρ$ mode wave function should be given by other nonrelativistic methods, e.g., the Godfrey-Isgur model to give a complete wave function for a doubly heavy baryon.
Comments:
4 pages, 1 figure, a talk at the 8th International Conference on Quarks and Nuclear Physics
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1903.04374 [pdf]
JPS Conf.Proc.(2019)·1 citation
13
[Submitted on 11 Mar 2019] (cross-list from hep-ph)
Quark fragmentation as a probe of dynamical mass generation
Alberto Accardi (Hampton U. and Jefferson Lab)🇺🇸 · Andrea Signori (Argonne National Laboratory)🇺🇸
We address the propagation and hadronization of a struck quark by studying the gauge invariance of the color-averaged cut quark propagator, and by relating this to the single inclusive quark fragmentation correlator by means of new sum rules. Using suitable Wilson lines, we provide a gauge-invariant definition for the mass of the color-averaged dressed quark and decompose this into the sum of a current and an interaction-dependent component. The latter, which we argue is an order parameter for dynamical chiral symmetry breaking, also appears in the sum rule for the twist-3 $E ~$ fragmentation function, providing a specific experimental way to probe the dynamical generation of mass in Quantum Chromo Dynamics.
Comments:
published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1903.04458 [pdf]
PLB(2019)·23 citations

Affiliations

first authorsco-authorsvia INSPIRE

Dimensional effects in Efimov physics

Spectroscopic Assignments of the Excited B-Mesons

Electrical conductivity and Hall conductivity of hot and dense hadron gas in a magnetic field: a relaxation time approach

Multiparticle production and initial quasi-temperature from proton induced carbon collisions at pLab​=31 GeV/c

Localized rainbows in the QCD phase diagram

Doubly Heavy Baryons Expanded in 1/mQ​

Quark fragmentation as a probe of dynamical mass generation

Affiliations

Spectroscopic Assignments of the Excited $B$ -Mesons

Multiparticle production and initial quasi-temperature from proton induced carbon collisions at $p_{L ab} = 31$ GeV/ $c$

Doubly Heavy Baryons Expanded in $1/ m_{Q}$