Nuclear Theory·nucl-th

Wednesday·November 18, 2015

7 papers—2 primary·5 cross-listed

01
Hadron Spectroscopy in the Unquenched Quark Model
H. García-Tecocoatzi🇲🇽 · R. Bijker🇲🇽 · J. Ferretti🇮🇹 · E. Santopinto🇮🇹
We present the last applications of the unquenched quark model (UQM) to the description of flavour asymmetry and strangeness in the proton when baryon-meson components are included. In the meson sector, the UQM is used to calculate the charmonium and bottomonium spectra with self-energy corrections due to the coupling to the meson-meson continuum.
nucl-thJPS Conf.Proc.(2016)·1 citation
02
Consistent analysis of one-nucleon spectroscopic factors involving weakly- and strongly-bound nucleons
J. Okołowicz🇵🇱 · Y.H. Lam · M. Płoszajczak🇫🇷 · A.O. Macchiavelli🇺🇸 · N.A. Smirnova🇫🇷
There is a considerable interest in understanding the dependence of one-nucleon removal cross sections on the asymmetry of the neutron $S_{n}$ and proton $S_{p}$ separation energies, following a large amount of experimental data and theoretical analyses in a framework of sudden and eikonal approximations of the reaction dynamics. These theoretical calculations involve both the single-particle cross section and the shell-model description of the projectile initial state and final states of the reaction residues. The configuration mixing in shell-model description of nuclear states depends on the proximity of one-nucleon decay threshold but does it depend sensitively on $S_{n} - S_{p}$ ? To answer this question, we use the shell model embedded in the continuum to investigate the dependence of one-nucleon spectroscopic factors on the asymmetry of $S_{n}$ and $S_{p}$ for mirror nuclei $^{24}$ Si, $^{24}$ Ne and $^{28}$ S, $^{28}$ Mg and for a series of neon isotopes ( $20 \leq A \leq 28$ ).
nucl-thnucl-exPLB(2016)·6 citations
03
The Skyrme model in the BPS limit
C. Adam🇪🇸 · C. Naya🇪🇸 · J. Sanchez-Guillen🇪🇸 · R. Vazquez🇪🇸 · A. Wereszczynski🇵🇱
In this review, we summarise the main features of the BPS Skyrme model which provides a physically well-motivated idealisation of atomic nuclei and nuclear matter: 1) it leads to zero binding energies for classical solitons (while realistic binding energies emerge owing to the semiclassical corrections, the Coulomb interaction and isospin breaking); 2) it describes a perfect non-barotropic fluid already at the microscopic (field theoretical) level which allows to study thermodynamics beyond the mean-field limit. These properties allow for an approximate but analytical calculation of binding energies of the most abundant nuclei, for a determination of the equation of state of skyrmionic matter (both in the full field theory and in a mean-field approximation) as well as the description of neutron stars as Skyrme solitons with a very good agreement with available observational data. All these results suggest that the proper low energy effective model of QCD should be close to the BPS Skyrme model in a certain sense (a "near-BPS Skyrme model"), with a prominent role played by the BPS part.
↳ hep-thnucl-th19 citations
04
A Study of Quasi-parton Distribution Functions in the Diquark Spectator Model
Leonard Gamberg🇺🇸 · Zhong-Bo Kang🇺🇸 · Ivan Vitev🇺🇸 · Hongxi Xing🇺🇸
To facilitate lattice QCD calculations of nucleon structute, a set of quasi-parton distributions were recently introduced. These quasi-PDFs were shown to reduce to standard PDFs when the nucleon is boosted to high energies, $P_{z} \to \infty$ . Since taking such limit is not feasible in lattice simulations, it is essential to provide guidance for what values of $P_{z}$ the quasi-PDFs are good approximations of standard PDFs. Within the framework of the spectator diquark model, we evaluate both the up and down quarks' quasi-PDFs and standard PDFs for all leading-twist distributions (unpolarized distribution $f_{1}$ , helicity distribution $g_{1}$ , and transversity distribution $h_{1}$ ). We find that, for intermediate parton momentum fractions $x$ , quasi-PDFs are good approximations to standard PDFs (within $20 - 30%$ ) when $P_{z} ≳ 1.5 - 2$ GeV. On the other hand, for large $x \sim 1$ much larger $P_{z} > 4$ GeV is necessary to obtain a satisfactory agreement between the two sets. We further find that the Soffer positivity bound does not hold in general for quasi-PDFs.
↳ hep-phnucl-thPoS(2015)·10 citations
05
Energy loss of $B$ and $D$ mesons in PbPb collisions at $s_{N N}$ = 2.76 TeV
Kapil Saraswat🇮🇳 · Prashant Shukla🇮🇳 · Venktesh Singh🇮🇳
We present the calculations of collisional and radiative energy loss of $B$ and $D$ mesons in the medium produced in PbPb collisions at $s_{N N}$ = 2.76 TeV. The nuclear modification factor $R_{AA}$ of $B$ and $D$ mesons including shadowing and energy loss are calculated and compared with the measured data. While the $D$ meson $R_{AA}$ can be described in terms of the radiative energy loss alone, both the collisional as well as radiative energy loss are required to explain the $B$ meson measurements.
↳ hep-phnucl-thPoS(2015)·1 citation
06
Concurrent tests of Lorentz invariance in $β$ -decay experiments
K.K. Vos🇳🇱 · H.W. Wilschut🇳🇱 · R.G.E. Timmermans🇳🇱
Modern experiments on neutron and allowed nuclear $β$ decay search for new semileptonic interactions, beyond the ``left-handed'' electroweak force. We show that ongoing and planned $β$ -decay experiments, with isotopes at rest and in flight, can be exploited as sensitive tests of Lorentz invariance. The variety of correlations that involve the nuclear spin, the direction of the emitted $β$ particle, and the recoil direction of the daughter nucleus allow for relatively simple experiments that give direct bounds on Lorentz violation. The pertinent observables are decay-rate asymmetries and their dependence on sidereal time. We discuss the potential of several asymmetries that together cover a large part of the parameter space for Lorentz violation in the gauge sector. High counting statistics is required.
↳ hep-phhep-exnucl-exnucl-thPRC(2015)·15 citations
07
Quantum relativistic fluid at global thermodynamic equilibrium in curved spacetime
F. Becattini🇮🇹 · E. Grossi (University of Florence)🇮🇹
We present a new approach to the problem of the thermodynamical equilibrium of a quantum relativistic fluid in a curved spacetime in the limit of small curvature. We calculate the mean value of local operators by expanding the four-temperature Killing vector field in Riemann normal coordinates about the same spacetime point and we derive corrections with respect to the flat spacetime expressions. Thereby, we clarify the origin of the terms proportional to Riemann and Ricci tensors introduced in general hydrodynamic expansion of the stress-energy tensor.
↳ gr-qchep-thnucl-th2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Hadron Spectroscopy in the Unquenched Quark Model

Consistent analysis of one-nucleon spectroscopic factors involving weakly- and strongly-bound nucleons

The Skyrme model in the BPS limit

A Study of Quasi-parton Distribution Functions in the Diquark Spectator Model

Energy loss of B and D mesons in PbPb collisions at sNN​​ = 2.76 TeV

Concurrent tests of Lorentz invariance in β-decay experiments

Quantum relativistic fluid at global thermodynamic equilibrium in curved spacetime

Affiliations

Energy loss of $B$ and $D$ mesons in PbPb collisions at $s_{N N}$ = 2.76 TeV

Concurrent tests of Lorentz invariance in $β$ -decay experiments