Nuclear Theory·nucl-th
10 papers—7 primary·3 cross-listed
[Submitted on 16 Oct 2019]
In this paper we will show that one can summarize the major two particle reaction plane azimuthal correlations for Au + Au mid-central collisions at 200 GeV by defining a 2D azimuthal space which is a summary of the event by event average.
[Submitted on 16 Oct 2019]
A point-by-point answer to the comment authored by S. Ayik and D. Lacroix is presented. At this point in time this text is not aimed at being submitted to Phys. Rev. C or any other journal, unless the authors of the comment choose to follow such an avenue. I also suggest a possible formulation of a stochastic mean field approach free of the difficulties in the stochastic mean field model due to S. Ayik.
[Submitted on 17 Oct 2019]
Sudhir Pandurang Rode🇮🇳 · Partha Pratim Bhaduri🇮🇳 · Ankhi Roy🇮🇳
In this article, we examine the equation of state (EoS) dependence of the anisotropic flow parameters (, and ) of charged and identified hadrons, as a function of transverse momentum (), rapidity () and the incident beam energy () in mid-central Au + Au collisions in the energy range A GeV. Simulations are carried out by employing different variants of the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) model, namely the pure transport (cascade) mode and the hybrid mode. In the hybrid mode, transport calculations are coupled with the ideal hydrodynamical evolution. Within the hydrodynamic scenario, two different equations of state (EoS) viz. Hadron gas and Chiral + deconfinement EoS have been employed separately to possibly mimic the hadronic and partonic scenarios, respectively. It is observed that the flow parameters are sensitive to the onset of hydrodynamic expansion of the fireball in comparison to the pure transport approach. The results would be useful as predictions for the upcoming low energy experiments at Facility for Antiproton and Ion Research (FAIR) and Nuclotron-based Ion Collider fAcility (NICA).
[Submitted on 17 Oct 2019]
Tomoyuki Baba🇯🇵 · Masaaki Kimura🇯🇵
We investigate excited states of O by using the antisymmetrized molecular dynamics. It is found that five different types of cluster states exist which we call , higher-nodal , two molecular states, and linear-chain. The calculated -decay widths are compared with the observed data. The higher-nodal cluster states reasonably agree with resonances reported by the recent experiments. We predict that the -particle emission is dominant for the cluster states while the molecular states prefer the He emission.
[Submitted on 16 Oct 2019]
J. Rangel · M. R. Cortes · J. Lubian · L.F. Canto
We propose a new quantum mechanical method to evaluate complete and incomplete fusion in collisions of weakly bound nuclei. The method is applied to the system and the results are compared to experimental data. The overall agreement between theory and experiment is very good, above and below the Coulomb barrier.
[Submitted on 17 Oct 2019]
Christian Drischler🇺🇸 · Wick Haxton🇺🇸 · Kenneth McElvain🇺🇸 · Emanuele Mereghetti🇺🇸 · Amy Nicholson🇺🇸 · Pavlos Vranas🇺🇸 · André Walker-Loud🇺🇸
Exascale computing could soon enable a predictive theory of nuclear structure and reactions rooted in the Standard Model, with quantifiable and systematically improvable uncertainties. Such a predictive theory will help exploit experiments that use nucleons and nuclei as laboratories for testing the Standard Model and its limitations. Examples include direct dark matter detection, neutrinoless double beta decay, and searches for permanent electric dipole moments of the neutron and atoms. It will also help connect QCD to the properties of cold neutron stars and hot supernova cores. We discuss how a quantitative bridge between QCD and the properties of nuclei and nuclear matter will require a synthesis of lattice QCD (especially as applied to two- and three-nucleon interactions), effective field theory, and ab initio methods for solving the nuclear many-body problem. While there are significant challenges that must be addressed in developing this triad of theoretical tools, the rapid advance of computing is accelerating progress. In particular, we focus this review on the anticipated advances from lattice QCD and how these advances will impact few-body effective theories of nuclear physics by providing critical input, such as constraints on unknown low-energy constants of the effective (field) theories. We also review particular challenges that must be overcome for the successful application of lattice QCD for low-energy nuclear physics. We describe progress in developing few-body effective (field) theories of nuclear physics, with an emphasis on HOBET, a non-relativistic effective theory of nuclear physics, which is less common in the literature. We use the examples of neutrinoless double beta decay and the nuclear-matter equation of state to illustrate how the coupling of lattice QCD to effective theory might impact our understanding of symmetries and exotic astrophysical environments.
[Submitted on 17 Oct 2019]
Sara Fucini🇮🇹 · Matteo Rinaldi🇮🇹 · Sergio Scopetta🇮🇹
The status of realistic calculations of nuclear generalized parton distributions, entering the theoretical description of coherent deeply virtual Compton scattering off nuclei, is reviewed for trinucleons and for He, also in view of forthcoming measurements at the Jefferson Laboratory and at the future Electron Ion Collider.
[Submitted on 17 Oct 2019] (cross-list from quant-ph)
Dean Lee🇺🇸 · Joey Bonitati🇺🇸 · Gabriel Given🇺🇸 · Caleb Hicks🇺🇸 · Ning Li🇺🇸 · Bing-Nan Lu🇺🇸 · Abudit Rai🇺🇸 · Avik Sarkar🇺🇸 · Jacob Watkins🇺🇸
In the current era of noisy quantum devices, there is a need for quantum algorithms that are efficient and robust against noise. Towards this end, we introduce the projected cooling algorithm for quantum computation. The projected cooling algorithm is able to construct the localized ground state of any Hamiltonian with a translationally-invariant kinetic energy and interactions that vanish at large distances. The term "localized" refers to localization in position space. The method can be viewed as the quantum analog of evaporative cooling. We start with an initial state with support over a compact region of a large volume. We then drive the excited quantum states to disperse and measure the remaining portion of the wave function left behind. For the nontrivial examples we consider here, the improvement over other methods is substantial. The only additional resource required is performing the operations in a volume significantly larger than the size of the localized state. These characteristics make the projected cooling algorithm a promising tool for calculations of self-bound systems such as atomic nuclei.
[Submitted on 17 Oct 2019] (cross-list from hep-lat)
Kei Iida🇯🇵 · Etsuko Itou🇯🇵 · Tong-Gyu Lee🇯🇵
We delineate equilibrium phase structure and topological charge distribution of dense two-colour QCD at low temperature by using a lattice simulation with two-flavour Wilson fermions that has a chemical potential and a diquark source incorporated. We systematically measure the diquark condensate, the Polyakov loop, the quark number density and the chiral condensate with improved accuracy and extrapolation over earlier publications; the known qualitative features of the low temperature phase diagram, which is composed of the hadronic, Bose-Einstein condensed (BEC) and BCS phases, are reproduced. In addition, we newly find that around the boundary between the hadronic and BEC phases, nonzero quark number density occurs even in the hadronic phase in contrast to the prediction of the chiral perturbation theory (ChPT), while the diquark condensate approaches zero in a manner that is consistent with the ChPT prediction. At the highest , which is of order the inverse of the lattice spacing, all the above observables change drastically, which implies a lattice artifact. Finally, at temperature of order , where is the chiral transition temperature at zero chemical potential, the topological susceptibility is calculated from a gradient-flow method and found to be almost constant for all the values of ranging from the hadronic to BCS phase. This is a contrast to the case of in which the topological susceptibility becomes small as the hadronic phase changes into the quark-gluon plasma phase.
[Submitted on 17 Oct 2019] (cross-list from nucl-ex)
Arghya Chatterjee🇨🇳 · Yu Zhang🇨🇳 · Jingdong Zeng🇨🇳 · Nihar Ranjan Sahoo🇨🇳 · Xiaofeng Luo🇨🇳
We studied the centrality selection effect on cumulants (up to fourth order) and the cumulants ratios of net-proton multiplicity distributions in Au+Au collisions at = 7.7, 19.6 and 200 GeV from UrQMD model. The net-proton cumulants are calculated with collision centralities by using charged particle multiplicity from different pesudorapidity () region. By comparing the results from various collision centralities, we found that the autocorrelation effects are not significant in the results with collision centralities "refmult-3" and "refmult-2", which are using mid-rapidity charged particles but excluding (anti-)protons and analysis region, respectively. Furthermore, due to the contributions of spectator protons, we observed poor centrality resolution when using charged particles at forward region at low energies. This work can serve as a baseline for centrality selection of future fluctuations analysis in relativistic heavy-ion collisions.
first authorsco-authorsvia INSPIRE