Nuclear Theory·nucl-th

Wednesday·April 20, 2016

8 papers—7 primary·1 cross-listed

01
Correction methods for finite-acceptance effects in two-particle correlation analyses
Saehanseul Oh🇺🇸 · Tim Schuster🇨🇭 · Andreas Morsch🇺🇸 · Constantin Loizides🇺🇸
Two-particle angular correlations have been widely used as a tool to explore particle production mechanisms in heavy-ion collisions. The mixed-event technique is generally used as a standard method to correct for finite-acceptance effects. We demonstrate that event mixing only provides an approximate acceptance correction, and propose new methods for finite-acceptance corrections. Starting from discussions about 2-dimensional correction procedures, new methods are derived for specific assumptions on the properties of the signal, such as uniform signal distribution or $δ$ -function-like trigger particle distribution, and suitable for two-particle correlation analyses from particles at mid-rapidity and jet-hadron or high $p_{T}$ -triggered hadron-hadron correlations. Per-trigger associated particle yields from the mixed-event method and the new methods are compared through Monte Carlo simulations containing well-defined correlation signals. Significant differences are observed at large pseudorapidity differences in general and especially for asymmetric particle distribution like that produced in proton--nucleus collisions. The applicability and validity of the new methods are discussed in detail.
nucl-thnucl-exEur.Phys.J.Plus(2016)·5 citations
02
Electric dipole polarizability from first principles calculations
M. Miorelli · S. Bacca · N. Barnea · G. Hagen · G. R. Jansen · G. Orlandini · T. Papenbrock
The electric dipole polarizability quantifies the low-energy behaviour of the dipole strength and is related to critical observables such as the radii of the proton and neutron distributions. Its computation is challenging because most of the dipole strength lies in the scattering continuum. In this paper we combine integral transforms with the coupled-cluster method and compute the dipole polarizability using bound-state techniques. Employing different interactions from chiral effective field theory, we confirm the strong correlation between the dipole polarizability and the charge radius, and study its dependence on three-nucleon forces. We find good agreement with data for the 4He, 40Ca, and 16O nuclei, and predict the dipole polarizability for the rare nucleus 22O.
nucl-thPRC(2016)·67 citations
03
Determination of hadron-quark phase transition line from lattice QCD and two-solar-mass neutron star observations
Junpei Sugano🇯🇵 · Hiroaki Kouno🇯🇵 · Masanobu Yahiro🇯🇵
We aim at drawing the hadron-quark phase transition line in the QCD phase diagram by using the two phase model (TPM) in which the entanglement Polyakov-loop extended Nambu--Jona-Lasinio (EPNJL) model with vector-type four-quark interaction is used for the quark phase and the relativistic mean field (RMF) model is for the hadron phase. Reasonable TPM is constructed by using lattice QCD data and neutron star observations as reliable constraints. For the EPNJL model, we determine the strength of vector-type four-quark interaction at zero quark chemical potential from lattice QCD data on quark number density normalized by its Stefan-Boltzmann limit. For the hadron phase, we consider three RMF models, NL3, TM1 and model proposed by Maruyama, Tatsumi, Endo and Chiba (MTEC). We find that MTEC is most consistent with the neutron star observations and TM1 is the second best. Assuming that the hadron-quark phase transition occurs in the core of neutron star, we explore the density-dependence of vector-type four-quark interaction. Particularly for the critical baryon chemical potential at zero temperature, we determine a range for the quark phase to occur in the core of neutron star.
nucl-thPRD(2016)·4 citations
04
Deuteron potential using the noncritical holographic model
Litao Song🇨🇳 · Yongxin Liu🇨🇳 · Jie He🇨🇳
Deuteron has been studied using a noncritical holographic quantumchromodynamics model constructed in the six-dimensional Anti-de-Sitter supergravity background. The nucleus potential energy is calculated. The binding energy has been estimated as the minimum of the potential energy. The roles of various mesons in producing the deuteron potential energy are discussed in details.
nucl-th0 citations
05
Propagation of heavy baryons in heavy-ion collisions
Santosh K. Das🇮🇹 · Juan M. Torres-Rincon🇫🇷 · Laura Tolos🇪🇸 · Vincenzo Minissale🇮🇹 · Francesco Scardina🇮🇹 · Vincenzo Greco🇮🇹
The drag and diffusion coefficients of heavy baryons ( $Λ_{c}$ and $Λ_{b}$ ) in the hadronic phase created in the latter stage of the heavy-ion collisions at RHIC and LHC energies have been evaluated recently. In this work we compute some experimental observables, such as the nuclear suppression factor $R_{AA}$ and the elliptic flow $v_{2}$ of heavy baryons at RHIC and LHC energies, highlighting the role of the hadronic phase contribution to these observables, which are going to be measured at Run 3 of LHC. For the time evolution of the heavy quarks in the QGP and heavy baryons in the hadronic phase we use the Langevin dynamics. For the hadronization of the heavy quarks to heavy baryons we employ Peterson fragmentation functions. We observe a strong suppression of both the $Λ_{c}$ and $Λ_{b}$ . We find that the hadronic medium has a sizable impact on the heavy-baryon elliptic flow whereas the impact of hadronic medium rescattering is almost unnoticeable on the nuclear suppression factor. We evaluate the $Λ_{c} / D$ ratio at RHIC and LHC. We find that $Λ_{c} / D$ ratio remain unaffected due to the hadronic phase rescattering which enable it as a nobel probe of QGP phase dynamics along with its hadronization.
nucl-thhep-phnucl-exPRD(2016)·63 citations
06
Structure models: from shell model to ab initio methods
Sonia Bacca🇨🇦
A brief review of models to describe nuclear structure and reactions properties is presented, starting from the historical shell model picture and encompassing modern ab initio approaches. A selection of recent theoretical results on observables for exotic light and medium-mass nuclei is shown. Emphasis is given to the comparison with experiment and to what can be learned about three-body forces and continuum properties.
nucl-thEur.Phys.J.Plus(2016)·10 citations
07
The Impact of New Polarization Data from Bonn, Mainz and Jefferson Laboratory on $γ p \to π N$ Multipoles
A.V. Anisovich R. Beck · M. Döring · M. Gottschall · J. Hartmann · V. Kashevarov · E. Klempt · Ulf-G. Meißner · V. Nikonov · M. Ostrick · D. Rönchen · A. Sarantsev · I. Strakovsky and 5 other authors
New data on pion-photoproduction off the proton have been included in the partial wave analyses Bonn-Gatchina and SAID and in the dynamical coupled-channel approach Jülich-Bonn. All reproduce the recent new data well: the double polarization data for E, G, H, P and T in $γ p \to π^{0} p$ from ELSA, the beam asymmetry $Σ$ for $γ p \to π^{0} p$ and $π^{+} n$ from Jefferson Laboratory, and the precise new differential cross section and beam asymmetry data $Σ$ for $γ p \to π^{0} p$ from MAMI. The new fit results for the multipoles are compared with predictions not taking into account the new data. The mutual agreement is improved considerably but still far from being perfect.
nucl-thnucl-exEPJA(2016)·85 citations
08
Ratio between two $Λ$ and $Λ ˉ$ production mechanisms in $p$ scattering
B. Hoeneisen🇪🇨
We consider $Λ$ and $Λ ˉ$ production in a wide range of proton scattering experiments. The produced $Λ$ and $Λ ˉ$ may or may not contain a diquark remnant of the beam proton. The ratio of these two production mechanisms is found to be a simple universal function $r = [κ / (y_{p} - y)]^{i}$ of the rapidity difference $y_{p} - y$ of the beam proton and the produced $Λ$ or $Λ ˉ$ , valid over four orders of magnitude, from $r \approx 0.01$ to $r \approx 100$ , with $κ = 2.86 \pm 0.03 \pm 0.07$ , and $i = 4.39 \pm 0.06 \pm 0.15$ .
↳ hep-phnucl-thPLB(2016)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE