Nuclear Theory·nucl-th

Wednesday·April 24, 2019

10 papers—4 primary·6 cross-listed

01
[Submitted on 20 Apr 2019]
Nuclear structure investigation of even-even Sn isotopes within the covariant density functional theory
Younes El Bassem · Mostafa Oulne
The current investigation aims to study the ground-state properties of one of the most interesting isotopic chains in the periodic table, 94-168Sn, from the proton drip line to the neutron drip line by using the covariant density functional theory, which is a modern theoretical tool for the description of nuclear structure phenomena. The physical observables of interest include the binding energy, separation energy, two-neutron shell gap, rms-radii for protons and neutrons, pairing energy and quadrupole deformation. The calculations are performed for a wide range of neutron numbers, starting from the proton-rich side up to the neutron-rich one, by using the density-dependent meson-exchange and the density dependent point-coupling effective interactions. The obtained results are discussed and compared with available experimental data and with the already existing results of relativistic Mean Field (RMF) model with NL3 functional. The shape phase transition for Sn isotopic chain is also investigated. A reasonable agreement is found between our calculated results and the available experimental data.
Comments:
17 pages, 9 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1904.10318 [pdf]
NPA(2019)·15 citations
02
[Submitted on 23 Apr 2019]
Primordial non-Gaussianity in heavy-ion collisions
Rajeev S. Bhalerao🇮🇳 · Giuliano Giacalone🇫🇷 · Jean-Yves Ollitrault🇫🇷
We show that experimental data on cumulants of anisotropic flow in heavy-ion collisions probe the non-Gaussian statistics of the energy density field created right after the collision. We carry out a perturbative expansion of the initial anisotropies of the system in terms of its density fluctuations. We argue that the correlation between the magnitudes of elliptic flow and triangular flow, dubbed $sc (3, 2)$ , is generically of the same sign and order of magnitude as the kurtosis of triangular flow in a hydrodynamic picture. The experimental observation that these quantities are negative implies that the distribution of energy around a given point has positive skew.
Comments:
11 pages, 4 figures; v2: minor revisions
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1904.10350 [pdf]
PRC(2019)·14 citations
03
[Submitted on 23 Apr 2019]
Applicability of Relativistic Point-Coupling Models to Neutron Star Physics
Bao Yuan Sun🇨🇳 · Zhi Wei Liu🇨🇳 · Ruo Yu Xing🇨🇳
Comparing with a wide range of covariant energy density functional models based on the finite-range meson-exchange representation, the relativistic mean-field models with the zero-range contact interaction, namely the relativistic point-coupling models, are still infrequent to be utilized in establishing nuclear equation of state (EoS) and investigating neutron star properties, although comprehensive applications and achievements of them in describing many nuclear properties both in ground and exited states are mature. In this work, the EoS of neutron star matter is established constructively in the framework of the relativistic point-coupling models to study neutron star physics. Taking two selected functionals DD-PC1 and PC-PK1 as examples, nuclear symmetry energies and several neutron star properties including proton fractions, mass-radius relations, the core-crust transition density, the fraction of crustal moment of inertia and dimensionless tidal deformabilities are discussed. A suppression of pressure of neutron star matter found in the functional PC-PK1 at high densities results in the difficulty of its prediction when approaching to the maximum mass of neutron stars. In addition, the divergences between two selected functionals in describing neutron star quantities mentioned above are still large, ascribing to the less constrained behavior of these functionals at high densities. Then it is expected that the constraints on the dense matter EoS from precise and massive modern astronomical observations, such as the tidal-deformabilities taken from gravitational-wave events, would be essential to improve the parameterizing of the relativistic point-coupling models.
Comments:
To appear in the AIP Proceedings of the Xiamen-CUSTIPEN Workshop on the EOS of Dense Neutron-Rich Matter in the Era of Gravitational Wave Astronomy, Jan. 3-7, Xiamen, China
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
arXiv:
1904.10372 [pdf]
AIP Conf.Proc.(2019)·5 citations
04
[Submitted on 23 Apr 2019]
Full distribution of clusters with universal couplings and in-medium effects
Helena Pais🇵🇹 · Francesca Gulminelli🇫🇷 · Constança Providência🇵🇹 · Gerd Röpke🇩🇪
Light and heavy clusters are calculated for asymmetric warm nuclear matter in a relativistic mean-field approach. In-medium effects, introduced via a universal cluster-meson coupling, and a binding energy shift contribution, calculated in a Thomas-Fermi approximation, were taken into account. This work considers, besides the standard lightest bound clusters $^{4}$ He, $^{3}$ He, $^{3}$ H, and $^{2}$ H, also stable and unstable clusters with higher number of nucleons, in the range $5 \leq A \leq 12$ , as it is natural that heavier clusters also form in core-collapse supernova matter, before the pasta phases set in. We show that these extra degrees of freedom contribute with non-negligible mass fractions to the composition of nuclear matter, and may prevail over deuterons and $α$ particles at high density in strongly asymmetric matter, and not too high temperatures. The presence of the light clusters reduces the contribution of heavy clusters to a much smaller density range, and to a smaller mass fraction.
Comments:
17 pages, 14 figures, accepted for publication in PRC
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
1904.10373 [pdf]
PRC(2019)·36 citations
05
[Submitted on 28 Jan 2019] (cross-list from hep-ph)
Chiral Lagrangians for mesons with a single heavy quark
Shao-Zhou Jiang🇨🇳 · Yan-Rui Liu🇨🇳 · Qin-He Yang🇨🇳
We construct the relativistic chiral Lagrangians for heavy-light mesons $(Q q ˉ)$ to the $O (p^{4})$ order. From $O (p^{2})$ to $O (p^{4})$ , there are 17, 67, and 404 independent terms in the flavor $S U (2)$ case and 20, 84, and 655 independent terms in the flavor $S U (3)$ case. The Lagrangians in the heavy quark limit are also obtained. From $O (p^{2})$ to $O (p^{4})$ , there are 7, 25, and 136 independent terms in the flavor $S U (2)$ case and 8, 33, and 212 independent terms in the flavor $S U (3)$ case. The relations between low-energy constants based on the heavy quark symmetry are also given up to the $O (p^{3})$ order.
Comments:
22 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
1901.09479 [pdf]
PRD(2019)·18 citations
06
[Submitted on 22 Apr 2019] (cross-list from hep-th)
Finite temperature CFT results for all couplings: O(N) model in 2+1 dimensions
Paul Romatschke🇺🇸
A famous example of gauge/gravity duality is the result that the entropy density of strongly coupled $N = 4$ SYM in four dimensions for large N is exactly 3/4 of the Stefan-Boltzmann limit. In this work, I revisit the massless O(N) model in 2+1 dimensions, which is analytically solvable at finite temperature $T$ for all couplings $λ$ in the large N limit. I find that the entropy density monotonically decreases from the Stefan-Boltzmann limit at $λ = 0$ to exactly 4/5 of the Stefan-Boltzmann limit at $λ = \infty$ . Calculating the retarded energy-momentum tensor correlator in the scalar channel at $λ = \infty$ , I find that it has two logarithmic branch cuts originating at $ω = \pm 4 T ln \frac{1 + 5}{2}$ , but no singularities in the whole complex frequency plane. I show that the ratio 4/5 and the location of the branch points both are universal within a large class of bosonic CFTs in 2+1 dimensions.
Comments:
5 pages, 1 figure; v2: typos fixed, new section on universality of 4/5 ratio; v3: matches published version; v4: typos/errors corrected
Subjects:
High Energy Physics — Theory (hep-th); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1904.09995 [pdf]
PRL(2019)·36 citations
07
[Submitted on 22 Apr 2019] (cross-list from hep-ph)
Proton-proton forward scattering at the LHC
M. Broilo🇧🇷 · D. A. Fagundes🇧🇷 · E. G. S. Luna🇧🇷 · M. J. Menon🇧🇷
Recently the TOTEM experiment at the LHC has released measurements at $s = 13$ TeV of the proton-proton total cross section, $σ_{t o t}$ , and the ratio of the real to imaginary parts of the forward elastic amplitude, $ρ$ . Since then an intense debate on the $C$ -parity asymptotic nature of the scattering amplitude was initiated. We examine the proton-proton and the antiproton-proton forward data above 10 GeV in the context of an eikonal QCD-based model, where nonperturbative effects are readily included via a QCD effective charge. We show that, despite an overall satisfactory description of the forward data is obtained by a model in which the scattering amplitude is dominated by only crossing-even elastic terms, there is evidence that the introduction of a crossing-odd term may improve the agreement with the measurements of $ρ$ at $s = 13$ TeV. In the Regge language the dominant even(odd)-under-crossing object is the so called Pomeron (Odderon).
Comments:
5 pages, 2 figures, 1 table. Phenomenological approach revised, results and conclusions changed, suggesting now the presence of Odderon effects in forward scattering (once confirmed the TOTEM data at 13 TeV)
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1904.10061 [pdf]
PLB(2019)·12 citations
08
[Submitted on 23 Apr 2019] (cross-list from hep-ph)
Triply-heavy baryons in a constituent quark model
Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Pablo G. Ortega🇪🇸 · Jorge Segovia🇪🇸
A constituent quark model, which has recently been successfully applied to the study of heavy quarkonium properties such as its spectrum but also a diverse array of observables related with their electromagnetic, strong and weak decays and reactions, is used herein to compute ground- and excited-state masses of $QQQ$ -baryons containing either $c$ - or $b$ -quarks. Considering the lack of experimental information about the spectra of triply-heavy baryons, we believe that our computation could help on finding new states, since it is expected that phenomenological quark models describe triply-heavy baryons to a similar degree of accuracy as heavy quarkonia. The quark model parameters previously used to describe $c c ˉ$ and $b b ˉ$ properties have not been modified for this analysis. The non-relativistic three-body bound-state problem is solved by means of the Gaußian expansion method which provides enough accuracy and simplifies the subsequent evaluation of the matrix elements. Several low-lying states with quantum numbers $J^{P} = \frac{1}{2}^{\pm}$ , $\frac{3}{2}^{\pm}$ , $\frac{5}{2}^{\pm}$ and $\frac{7}{2}^{+}$ are reported. We compare our results with those predicted by many other theoretical formalisms. There is a general trend of agreement about the mass of the ground state in each sector of triply-heavy baryons; however, the situation is more puzzling for the excited states and thus appropriate comments on the most relevant features of our comparison are given.
Comments:
12 pages, 10 tables, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1904.10166 [pdf]
CPC(2020)·77 citations
09
[Submitted on 23 Apr 2019] (cross-list from nucl-ex)
Disentangle contributions to small-system collectivity via scans of light nucleus-nucleus collisions
Shengli Huang🇺🇸 · Zhenyu Chen🇺🇸 · Jiangyong Jia🇺🇸 · Wei Li🇺🇸
The observation of multi-particle azimuthal correlations in high-energy small-system collisions has led to intense debate on its origin and the possible coexistence from two competing theoretical scenarios: one based on initial-state intrinsic momentum anisotropy (ISM), and the other based on final-state collective response to the collision geometry (FSM). To complement the previous scan of asymmetric collision systems ( $p$ +Au, $d$ +Au and He+Au), we propose a scan of small symmetric collision systems at RHIC, such as C+C, O+O, Al+Al and Ar+Ar $s_{NN} = 0.2$ TeV, to provide further insights in disentangling contributions from these two scenarios. These symmetric small systems have the advantage of providing a better controlled initial geometry dominated by the average shape of the overlap region, as opposed to fluctuation-driven geometries in asymmetric systems. A transport model is employed to investigate the expected geometry response in the FSM scenario. Different trends of elliptic flow with increasing charge particle multiplicity are observed between symmetric and asymmetric systems, while triangular flow appears to show a similar behavior. Furthermore, a comparison of O+O collisions at $s_{NN} = 0.2$ TeV and at $s_{NN} = 2.76 - 7$ TeV, as proposed at the LHC, provides a unique opportunity to disentangle the collision geometry effects at nucleon level from those arising from subnucleon fluctuations.
Comments:
6 pages, 6 figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1904.10415 [pdf]
PRC(2020)·46 citations
10
[Submitted on 23 Apr 2019] (cross-list from quant-ph)
Minimally-Entangled State Preparation of Localized Wavefunctions on Quantum Computers
Natalie Klco🇺🇸 · Martin J. Savage🇺🇸
Initializing a single site of a lattice scalar field theory into an arbitrary state with support throughout the quantum register requires $O (2^{n_{Q}})$ entangling gates on a quantum computer with $n_{Q}$ qubits per site. It is conceivable that, instead, initializing to functions that are good approximations to states may have utility in reducing the number of required entangling gates. In the case of a single site of a non-interacting scalar field theory, initializing to a symmetric exponential wavefunction requires $n_{Q} - 1$ entangling gates, compared with the $2^{n_{Q} - 1} + n_{Q} - 3 + δ_{n_{Q}, 1}$ required for a symmetric Gaussian wavefunction. In this work, we explore the initialization of 1-site ( $n_{Q} = 4$ ), 2-site ( $n_{Q} = 3$ ) and 3-site ( $n_{Q} = 3$ ) non-interacting scalar field theories with symmetric exponential wavefunctions using IBM's quantum simulators and quantum devices (Poughkeepsie and Tokyo). With the digitizations attainable with $n_{Q} = 3, 4$ , these tensor-product wavefunctions are found to have large overlap with a Gaussian wavefunction, and provide a suitable low-noise initialization for improvement and \emph{Somma Inflation}. In performing these simulations, we have employed a workflow that interleaves calibrations to mitigate systematic errors in production. The calibrations allow tolerance cuts on gate performance including the fidelity of the symmetrizing Hadamard gate, both in vacuum ( $∣ 0 ⟩^{\otimes n_{Q}}$ ) and in medium ( $n_{Q} - 1$ qubits initialized to an exponential function). The results obtained in this work are relevant to systems beyond scalar field theories, such as the deuteron radial wavefunction, 2- and 3-dimensional cartesian-space wavefunctions, and non-relativistic multi-nucleon systems built on a localized eigenbasis.
Comments:
47 pages, 17 figures
Subjects:
Quantum Physics (quant-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
1904.10440 [pdf]
PRA(2020)·92 citations

Affiliations

first authorsco-authorsvia INSPIRE