Nuclear Theory·nucl-th

Friday·July 10, 2020

14 papers—5 primary·9 cross-listed

01
The Equation of State of Nuclear Matter : from Finite Nuclei to Neutron Stars
G. F. Burgio🇮🇹 · I. Vidana (INFN Sezione di Catania)🇮🇹
{\it Background.} We investigate possible correlations between neutron star observables and properties of atomic nuclei. Particularly, we explore how the tidal deformability of a 1.4 solar mass neutron star, $M_{1.4}$ , and the neutron skin thickness of $^{48}$ Ca and $^{208}$ Pb are related to the stellar radius and the stiffness of the symmetry energy. {\it Methods.} We examine a large set of nuclear equations of state based on phenomenological models (Skyrme, NLWM, DDM) and {\it ab-initio} theoretical methods (BBG, Dirac-Brueckner, Variational, Quantum Monte Carlo). {\it Results.} We find strong correlations between tidal deformability and NS radius, whereas a weaker correlation does exist with the stiffness of the symmetry energy. Regarding the neutron skin thickness, weak correlations appear both with the stiffness of the symmetry energy, and the radius of a $M_{1.4}$ . {\it Conclusion.} The tidal deformability of a $M_{1.4}$ and the neutron-skin thickness of atomic nuclei show some degree of correlation with nuclear and astrophysical observables, which however depends on the ensemble of adopted EoS.
nucl-thastro-ph.HEUniverse(2020)·54 citations
02
Fast Heating Dissociation of Upsilon(1S) in Heavy Ion Collisions at RHIC
Yunpeng Liu · Baoyi Chen
With the adiabatic assumption in the cooling process, we discussed a new mechanism on Upsilon(1S) suppression that is due to the fast heating process at the early stage of the fireball instead of its finite decay width in finite temperature medium produced in the heavy ion collisions. We calculated the transition probability after the fast heating dissociation as a function of the temperature of the medium and the nuclear modification factor in central collisions, and found that the suppression is not negligible at RHIC, even if the width of Upsilon(1S) vanishes.
nucl-thCPC(2020)·3 citations
03
Mass spectrum of Mesons via the WKB approximation method
Ekwevugbe Omugbe · Omosede E. Osafile · Michael C. Onyeaju
In this paper, we demonstrated that the multiple turning point problems within the framework of the Wentzel-Kramers-Brillouin (WKB) approximation method can be reduced to two turning point one for a non-symmetric potential function by using an appropriate Pekeris-type approximation scheme. We solved the Schrödinger equation with the Killingbeck potential plus an inversely quadratic potential (KPIQP) function. The special cases of the modeled potential are discussed. We obtained the energy eigenvalues and the mass spectra of the heavy and heavy-light mesons systems. The results in this present work are in good agreement with the results obtained by other analytical methods and available experimental data in the literature
nucl-thAdv.High Energy Phys.(2020)·20 citations
04
Nucleon clustering at kinetic freezeout of heavy-ion collisions via path-integral Monte Carlo
Dallas DeMartini🇺🇸 · Edward Shuryak🇺🇸
Clustering of the four-nucleon system at kinetic freezeout conditions is studied using path-integral Monte Carlo techniques. This method seeks to improve upon previous calculations which relied on approximate semiclassical methods or few-body quantum mechanics. Estimates are given for the decay probabilities of the 4N system into various light nuclei decay channels and the strength of spatial correlations is characterized. Additionally, a simple model is presented to describe the impact of this clustering on nucleon multiplicity distributions. The effects of a possible modification of the inter-nucleon interaction due to the close critical line (and hypothetical QCD critical point) on the clustering are also studied.
nucl-thhep-phNPA(2021)·10 citations
05
Gamow-Teller strength in $^{48}$ Ca and $^{78}$ Ni with the charge-exchange subtracted second random-phase approximation
D. Gambacurta🇮🇹 · M. Grasso🇫🇷 · J. Engel🇺🇸
We develop a fully self-consistent subtracted second random-phase approximation for charge-exchange processes with Skyrme energy-density functionals. As a first application, we study Gamow-Teller excitations in the doubly-magic nucleus $^{48}$ Ca, the lightest double- $β$ emitter that could be used in an experiment, and in $^{78}$ Ni, the single-beta-decay rate of which is known. The amount of Gamow-Teller strength below 20 or 30 MeV is considerably smaller than in other energy-density-functional calculations and agrees better with experiment in $^{48}$ Ca, as does the beta-decay rate in $^{78}$ Ni. These important results, obtained without \textit{ad hoc} quenching factors, are due to the presence of two-particle -- two-hole configurations. Their density progressively increases with excitation energy, leading to a long high-energy tail in the spectrum, a fact that may have implications for the computation of nuclear matrix elements for neutrinoless double- $β$ decay in the same framework.
nucl-thnucl-exPRL(2020)·48 citations
06
Higher Anomalies, Higher Symmetries, and Cobordisms III: QCD Matter Phases Anew
Zheyan Wan🇨🇳 · Juven Wang🇺🇸
We explore QCD $_{4}$ quark matter, the $μ$ -T (chemical potential-temperature) phase diagram, possible 't Hooft anomalies, and topological terms, via non-perturbative tools of cobordism theory and higher anomaly matching. We focus on quarks in 3-color and 3-flavor on bi-fundamentals of SU(3), then analyze the continuous and discrete global symmetries and pay careful attention to finite group sectors. We input constraints from $T = C P$ or $C T$ time-reversal symmetries, implementing QCD on unorientable spacetimes and distinct topology. Examined phases include the high T QGP (quark-gluon plasma/liquid), the low T ChSB (chiral symmetry breaking), 2SC (2-color superconductivity) and CFL (3-color-flavor locking superconductivity) at high density. We introduce a possibly useful but only approximate higher anomaly, involving discrete 0-form axial and 1-form mixed chiral-flavor-locked center symmetries, matched by the above four QCD phases. We also enlist as much as possible, but without identifying all of, 't Hooft anomalies and topological terms relevant to Symmetry Protected/Enriched Topological states (SPTs/SETs) of gauged SU(2) or SU(3) QCD $_{d}$ -like matter theories in general in any spacetime dimensions $d = 2, 3, 4, 5$ via cobordism.
↳ hep-thcond-mat.supr-conhep-phmath.AT+1NPB(2020)·39 citations
07
Precision Global Determination of the $B \to X_{s} γ$ Decay Rate
SIMBA collaboration: Florian U. Bernlochner🇩🇪 · Heiko Lacker🇩🇪 · Zoltan Ligeti🇺🇸 · Iain W. Stewart🇺🇸 · Frank J. Tackmann🇩🇪 · Kerstin Tackmann🇩🇪
We perform the first global fit to inclusive $B \to X_{s} γ$ measurements using a model-independent treatment of the nonperturbative $b$ -quark distribution function, with next-to-next-to-leading logarithmic resummation and $O (α_{s}^{2})$ fixed-order contributions. The normalization of the $B \to X_{s} γ$ decay rate, given by $∣ C_{7}^{incl} V_{t b} V_{t s}^{*} ∣^{2}$ , is sensitive to physics beyond the Standard Model (SM). We determine $∣ C_{7}^{incl} V_{t b} V_{t s}^{*} ∣ = (14.77 \pm 0.5 1_{fit} \pm 0.5 9_{theory} \pm 0.0 8_{param}) \times 1 0^{- 3}$ , in good agreement with the SM prediction, and the $b$ -quark mass $m_{b}^{1 S} = (4.750 \pm 0.02 7_{fit} \pm 0.03 3_{theory} \pm 0.00 3_{param}) GeV$ . Our results suggest that the uncertainties in the extracted $B \to X_{s} γ$ rate have been underestimated by up to a factor of two, leaving more room for beyond-SM contributions.
↳ hep-phhep-exnucl-thPRL(2021)·57 citations
08
Hydrodynamics of simply spinning black holes & hydrodynamics for spinning quantum fluids
Markus Garbiso🇺🇸 · Matthias Kaminski🇺🇸
We find hydrodynamic behavior in large simply spinning five-dimensional Anti-de Sitter black holes. These are dual to spinning quantum fluids through the AdS/CFT correspondence constructed from string theory. Due to the spatial anisotropy introduced by the angular momentum in the system, hydrodynamic transport coefficients split into one group longitudinal and another transverse to the angular momentum. Analytic expressions are provided for the two shear viscosities, the longitudinal momentum diffusion coefficient, two speeds of sound, and two sound attenuation coefficients. Known relations between these coefficients are generalized to include dependence on angular momentum. The shear viscosity to entropy density ratio varies between zero and 1/(4 $π$ ) depending on the direction of the shear. These results can be applied to heavy ion collisions, in which the most vortical fluid was reported recently. In passing, we show that large simply spinning five-dimensional Myers-Perry black holes are perturbatively stable for all angular momenta below extremality.
↳ hep-thhep-phnucl-thJHEP(2020)·85 citations
09
An Algorithm for Quantum Computation of Particle Decays
Anthony Ciavarella🇺🇸
A quantum algorithm is developed to calculate decay rates and cross sections using quantum resources that scale polynomially in the system size assuming similar scaling for state preparation and time evolution. This is done by computing finite-volume one- and two-particle Green's functions on the quantum hardware. Particle decay rates and two particle scattering cross sections are extracted from the imaginary parts of the Green's function. A $0 + 1$ dimensional implementation of this method is demonstrated on IBM's superconducting quantum hardware for the decay of a heavy scalar particle to a pair of light scalars.
↳ hep-thhep-latnucl-thquant-phPRD(2020)·45 citations
10
Myth of scattering in finite volume
Peng Guo🇺🇸
In this notes, we illustrate why the infinite volume scattering amplitude is in fact dispensable when it comes to formulating few-body quantization condition in finite volume. Only subprocess interactions or interactions associated subprocess amplitudes are essential and fundamental ingredients of quantization conditions. After these ingredients are determined, infinite volume scattering amplitude can be computed separately. The underlying reasons are rooted in facts that (1) the final physical process is generated by all subprocess or interactions among particles; (2) the ultimate goal of quantization condition in finite volume is to find stationary solutions of few-body system. That is to say, in the end, it all comes down to the solving of eigenvalue problem, $H^∣ n ⟩ = E_{n} ∣ n ⟩$ .
↳ hep-lathep-phnucl-th10 citations
11
Density dependent quark mass model revisited: Thermodynamic consistency, stability windows and stellar properties
B. C. Backes🇧🇷 · E. Hafemann🇧🇷 · I. Marzolla🇧🇷 · D. P. Menezes🇧🇷
In this work a density dependent quark model is revisited, its thermodynamic consistency checked and the stability window for absolutely stable quark matter obtained. The hypotheses of both pure quark matter with equal quark chemical potentials and stellar matter subject to chemical stability and charge neutrality are investigated. The parameters that appear in the density dependent mass and satisfy the Bodmer-Witten conjecture are then used to compute the masses and radii of strange stars. We show that the obtained values are compatible with the recently observed massive stars.
↳ hep-phastro-ph.HEnucl-thJ.Phys.G(2021)·34 citations
12
Gravitational-wave Signature of a First-order Quantum Chromodynamics Phase Transition in Core-Collapse Supernovae
Shuai Zha🇸🇪 · Evan P. O'Connor🇸🇪 · Ming-chung Chu🇨🇳 · Lap-Ming Lin🇨🇳 · Sean M. Couch🇺🇸
A first-order quantum chromodynamics (QCD) phase transition (PT) may take place in the protocompact star (PCS) produced by a core-collapse supernova (CCSN). In this work, we study the consequences of such a PT in a non-rotating CCSN with axisymmetric hydrodynamic simulations. We find that the PT leads to the collapse of the PCS and results in a loud burst of gravitational waves (GWs). The amplitude of this GW burst is $\sim 30$ times larger than the post-bounce GW signal normally found for non-rotating CCSN. It shows a broad peak at high frequencies ( $\sim 2500 - 4000$ Hz) in the spectrum, has a duration of $≲ 5 ms$ , and carries $\sim 3$ orders of magnitude more energy than the other episodes. Also, the peak frequency of the PCS oscillation increases dramatically after the PT-induced collapse. In addition to a second neutrino burst, the GW signal, if detected by the ground-based GW detectors, is decisive evidence of the first-order QCD PT inside CCSNe and provides key information about the structure and dynamics of the PCS.
↳ astro-ph.HEgr-qcnucl-thPRL(2020)·70 citations
13
Exploring the centrality dependence of elliptic and triangular flows
V.L. Korotkikh🇷🇺 · A.M. Snigirev🇷🇺
A detailed study of elliptical and triangular eccentricities in the initial state of relativistic heavy ion collisions is presented. A model of randomly distributed sources of energy density in the transverse plane based on the effective theory of Color Glass Condensate is used. This model describes well the ALICE and ATLAS data for Pb+Pb collisions at center-of-mass energy 5.02 TeV per nucleon pair in a wide range of centralities, if the second $v_{2}$ and third $v_{3}$ harmonics of the anisotropic flow are simply implied to be proportional to the eccentricities $ε_{2}$ and $ε_{3}$ as a reasonable approximation. The eccentricity $ε_{2}$ is closely related with the collision geometry and its centrality dependence is mainly determined by the edge diffuseness of the region of the uniform distribution of the saturation pulse of the oncoming nucleus. The eccentricity $ε_{3}$ is completely determined by the chaotic fluctuations of the source position in the region of overlapping nuclei and is substantially dependent on the overlap area only.
↳ hep-phnucl-exnucl-th0 citations
14
Strong CP violation in nuclear physics
Jordy de Vries🇺🇸 · Alex Gnech🇮🇹 · Sachin Shain🇺🇸
Electric dipole moments of nuclei, diamagnetic atoms, and certain molecules are induced by CP-violating nuclear forces. Naive dimensional analysis predicts these forces to be dominated by long-range one-pion-exchange processes, with short-range forces entering only at next-to-next-to-leading order in the chiral expansion. Based on renormalization arguments we argue that a consistent picture of CP-violating nuclear forces requires a leading-order short-distance operator contributing to $^{1} S_{0}$ - $^{3} P_{0}$ transitions, due to the attractive and singular nature of the strong tensor force in the $^{3} P_{0}$ channel. The short-distance operator leads to $O (1)$ corrections to static and oscillating, relevant for axion searches, electric dipole moments. We discuss strategies how the finite part of the associated low-energy constant can be determined in the case of CP violation from the QCD theta term by the connection to charge-symmetry violation in nuclear systems.
↳ hep-phnucl-thPRC(2021)·21 citations

Affiliations

first authorsco-authorsvia INSPIRE