Nuclear Theory·nucl-th

Tuesday·November 28, 2017

20 papers—11 primary·9 cross-listed

12
[Submitted on 22 Nov 2017] (cross-list from nucl-ex)
Hard exclusive pion electroproduction at backward angles with CLAS
K. Park · M. Guidal · R.W. Gothe · B. Pire · K. Semenov-Tian-Shansky · J.-M. Laget
We report on the first measurement of cross sections for exclusive deeply virtual pion electroproduction off the proton, $e p \to e^{'} n π^{+}$ , above the resonance region at backward pion center-of-mass angles. The $φ_{π}^{*}$ -dependent cross sections were measured, from which we extracted three combinations of structure functions of the proton. Our results are compatible with calculations based on nucleon-to-pion transition distribution amplitudes (TDAs) and shed new light on nucleon structure.
Comments:
7 pages, 6figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.08486 [pdf]
PLB(2018)·30 citations
13
[Submitted on 26 Nov 2017] (cross-list from hep-lat)
Comment on "Relation between scattering amplitude and Bethe-Salpeter wave function in quantum field theory"
Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Noriyoshi Ishii🇯🇵
We invalidate the arguments given in [T.Yamazaki and Y.Kuramashi, Phys. Rev. D96, 114511 (2017)] over the HAL QCD method for hadron-hadron interactions on the lattice. We also pose questions on the practical usefulness of the method proposed in this reference.
Comments:
3 pages. Version accepted for publication in Physical Review D
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.09344 [pdf]
PRD(2018)·12 citations
14
[Submitted on 26 Nov 2017] (cross-list from cond-mat.stat-mech)
Nonextensive statistics based on Landsberg-Vedral entropy
A.S. Parvan
The general formalism for the nonextensive statistics based on the Landsberg-Vedral entropy was derived. The formula for the first law of thermodynamics and the exact relations of the thermodynamic quantities to their ensemble averages were obtained. It was found that under the transformation $q \to 2 - q$ the probabilities of microstates of the nonextensive statistics based on the Landsberg-Vedral entropy formally resemble the corresponding probabilities of the Tsallis statistics with escort probabilities. However, the nonextensive statistics with the Landsberg-Vedral entropy does not require introduction of the escort probabilities and generalized expectation values which are used in this version of the Tsallis statistics.
Subjects:
Statistical Mechanics (cond-mat.stat-mech); Nuclear Theory (nucl-th)
arXiv:
1711.09354 [pdf]
EPJ Web Conf.(2019)·1 citation
15
[Submitted on 26 Nov 2017] (cross-list from astro-ph.HE)
Hyperons in hot dense matter: what do the constraints tell us for equation of state?
M. Fortin🇵🇱 · M. Oertel🇫🇷 · C. Providência🇵🇹
For core-collapse and neutron star merger simulations it is important to have at hand adequate equations of state, describing the underlying dense and hot matter as realistically as possible. Here, we present two newly constructed equation of state (EoS) including the entire baryon octet. Both EoS are compatible with the main constraints from nuclear physics, both experimental and theoretical. One of the EoS is equally describing maximum mass for cold $β$ -equilibrated neutron stars of $2 M_{⊙}$ in agreement with recent observations. The predictions obtained with the new EoS are compared with the results obtained with DD2Y, the only presently existing EoS containing the baryon octet, that satisfies the same constraints within uncertainties. The main difference between our new EoS models and DD2Y is the harder symmetry energy of the latter. We show that the density dependence of the symmetry energy has a direct influence on the amount of strangeness inside hot and dense matter and consequently on thermodynamic quantities, e.g. the temperature for given entropy per baryon. We expect these differences to affect the evolution of a protoneutron star or binary neutron star mergers. We also propose several parametrizations calibrated to $Λ$ hypernuclei based on the DD2 and SFHo models that satisfy the two solar mass constraint.
Comments:
17 pages, 13 figures, 4 tables, contribution to PASA special issue on NewCompStar
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
1711.09427 [pdf]
Publ.Astron.Soc.Austral.(2018)·62 citations
16
[Submitted on 26 Nov 2017] (cross-list from hep-ph)
Femtoscopy of stopped protons
Andrzej Bialas🇵🇱 · Adam Bzdak🇵🇱 · Volker Koch🇺🇸
The longitudinal proton-proton femtoscopy (HBT) correlation function, based on the idea that in a heavy ion collision at $s ≲ 20$ GeV stopped protons are likely to be separated in configuration space, is evaluated. It shows a characteristic oscillation which appears sufficiently pronounced to be accessible in experiment. The proposed measurement is essential for estimating the baryon density in the central rapidity region, and can be also viewed as an (almost) direct verification of the Lorentz contraction of the fast-moving nucleus.
Comments:
8 pages, 3 figures; discussion on strong and Coulomb interactions included
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1711.09440 [pdf]
PRC(2019)·1 citation
17
[Submitted on 27 Nov 2017] (cross-list from hep-lat)
Chiral Symmetry and hadron properties at finite temperature -A numerical experiment
Teiji Kunihiro🇯🇵 · Shin Muroya🇯🇵 · Atsushi Nakamura🇷🇺 · Chiho Nonaka🇯🇵 · Motoo Sekiguchi🇯🇵 · Hiroaki Wada🇯🇵 · Masayuki Wakayama🇷🇺
We study the hadron properties at finite temperature from measurement of the screening masses, using two-flavor full QCD of the hybrid Monte Carlo (HMC) algorithm with the renormalization group improved Iwasaki gauge action and the clover improved Wilson quark action on a $1 6^{3} \times 4$ lattice. We explore rather heavy quark mass regions. Disconnected quark diagram is dropped. We observe the tendency that the screening masses in all the channels degenerate, which is in accord with the effective restoration of U $_{A}$ (1) symmetry, and then eventually approach 2 $π T$ , i.e. the free quark value. In the low temperature region below pseudocritical temperature $T_{c}$ , the screening masses in all the channels decrease. We discuss the different features between these calculations and the previous ones.
Comments:
8 pages, 6 figures
Subjects:
High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1711.09693 [pdf]
0 citations
18
[Submitted on 27 Nov 2017] (cross-list from hep-ph)
Predictions for multiplicities and flow harmonics in 5.44 TeV Xe+Xe collisions at the CERN Large Hadron Collider
K. J. Eskola🇫🇮 · H. Niemi🇩🇪 · R. Paatelainen🇫🇮 · K. Tuominen🇫🇮
We present the next-to-leading-order event-by-event EKRT model predictions for the centrality dependence of the charged hadron multiplicity in the pseudorapidity interval $∣ η ∣ \leq 0.5$ , and for the centrality dependence of the charged hadron flow harmonics $v_{n} {2}$ obtained from 2-particle cumulants, in $s_{N N} = 5.44$ TeV Xe+Xe collisions at the CERN Large Hadron Collider. Our prediction for the 0-5 \% central charged multiplicity is $d N_{ch} / d η = 1218 \pm 46$ . We also predict $v_{n} {2}$ in Xe+Xe collisions to increase more slowly from central towards peripheral collisions than those in a Pb+Pb system. We find that at $10 \dots 50$ \% centralities $v_{2} {2}$ is smaller and $v_{3} {2}$ is larger than in the Pb+Pb system while $v_{4} {2}$ is of the same magnitude in both systems. We also find that the ratio of flow harmonics in Xe+Xe collisions and in Pb+Pb collisions shows a slight sensitivity to the temperature dependence of the shear-viscosity-to-entropy ratio. As we discuss here, the new nuclear mass-number systematics especially in the flow harmonics serves as a welcome further constraint for describing the space-time evolution of a heavy-ion system and for determining the shear viscosity and other transport properties of strongly interacting matter.
Comments:
7 pages, 7 figures, revised version. The predicted flow coefficients vn with deformed Xe, and their ratios to 5.023 TeV Pb+Pb vn's are included as ancillary files
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1711.09803 [pdf]
PRC(2018)·52 citations
19
[Submitted on 27 Nov 2017] (cross-list from hep-th)
(Anti-)Symmetrizing Wave Functions
Chethan Krishnan🇮🇳 · K.V. Pavan Kumar🇮🇳 · P. N. Bala Subramanian🇮🇳
The construction of fully (anti-)symmetric states with many particles, when the single particle state carries multiple quantum numbers, is a problem that seems to have not been systematically addressed in the literature. A quintessential example is the construction of ground state baryon wave functions where the color singlet condition reduces the problem to just two (flavor and spin) quantum numbers. In this paper, we address the general problem by noting that it can be re-interpreted as an eigenvalue equation, and provide a formalism that applies to generic number of particles and generic number of quantum numbers. As an immediate result, we find a complete solution to the two quantum number case, from which the baryon wave function problem with arbitrary number of flavors follows. As a more elaborate illustration that reveals complications not visible in the two quantum number case, we present the complete class of states possible for a system of five fermionic particles with three quantum numbers each. Our formalism makes systematic use of properties of the symmetric group and Young tableaux. Even though our motivations to consider this question have their roots in SYK-like tensor models and holography, the problem and its solution should have broader applications.
Comments:
v3: journal version, contains slightly expanded discussions and examples
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Mathematical Physics (math-ph); math.MP (math.MP); Nuclear Theory (nucl-th)
arXiv:
1711.09811 [pdf]
J.Math.Phys.(2019)·4 citations
20
[Submitted on 27 Nov 2017] (cross-list from hep-ph)
Thermodynamic characterizations of exotic and missing states
Eugenio Megias🇪🇸 · Enrique Ruiz Arriola🇪🇸 · Lorenzo Luis Salcedo🇪🇸
Thermal shifts and fluctuations at finite temperature below the deconfinement crossover of QCD from hadronic matter to the Quark-Gluon Plasma provide a viable way to look for exotic and missing states with given quantum numbers in the hadronic spectrum. We study a realization of the Hadron Resonance Gas model in the light quark ( $u d s$ ) flavor sector of QCD to study: i) the entropy shifts, and ii) the fluctuations of electric charge, baryon number and strangeness; and extract from them the possible existence of missing and exotic states from a comparison with lattice data. The analysis of the entropy shift based on the free energy of the Polyakov loop suggests the existence of exotic hybrids $g q q ˉ$ and $g q q q$ .
Comments:
3 pages, 2 figures. Presented by E.Megias at the XVII International Conference on Hadron Spectroscopy and Structure (Hadron 2017), 25-29 September 2017, Salamanca, Spain
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1711.09837 [pdf]
PoS(2018)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE