Nuclear Theory·nucl-th

Friday·October 26, 2018

7 papers—2 primary·5 cross-listed

01
Tidal deformability with sharp phase transitions in (binary) neutron stars
Sophia Han🇺🇸 · Andrew W. Steiner🇺🇸
The neutron star tidal deformability is a critical parameter which determines the pre-merger gravitational-wave signal in a neutron star merger. In this article, we show how neutron star tidal deformabilities behave in the presence of one or two sharp phase transition(s). We characterize how the tidal deformability changes when the properties of these phase transitions are modified in dense matter equation of state (EoS). Sharp phase transitions lead to the smallest possible tidal deformabilities and also induce discontinuities in the relation between tidal deformability and gravitational mass. These results are qualitatively unmodified by a modest softening of the phase transition. Finally, we test two universal relations involving the tidal deformability and show that their accuracy is limited by sharp phase transitions.
nucl-thastro-ph.HEastro-ph.SRPRD(2019)·187 citations
02
Predicting the moment of inertia of pulsar J0737-3039A from Bayesian modeling of the nuclear equation of state
Yeunhwan Lim🇺🇸 · Jeremy W. Holt🇺🇸 · Robert J. Stahulak🇺🇸
We investigate neutron star moments of inertia from Bayesian posterior probability distributions of the nuclear equation of state that incorporate information from microscopic many-body theory and empirical data of finite nuclei. We focus on PSR J0737-3039A and predict that for this 1.338 M_sun neutron star the moment of inertia lies in the range $1.04 \times 1 0^{45}$ g cm $^{2} < I < 1.51 \times 1 0^{45}$ g cm $^{2}$ at the 95% credibility level, while the most probable value for the moment of inertia is $I ~ = 1.36 \times 1 0^{45}$ g cm $^{2}$ . Assuming a measurement of the PSR J0737-3039A moment of inertia to 10% precision, we study the implications for neutron star radii and tidal deformabilities. We also determine the crustal component of the moment of inertia and find that for typical neutron star masses of 1.3 M_sun < M < 1.5 M_sun the crust contributes 1% - 6% of the total moment of inertia, below what is needed to explain large pulsar glitches in the scenario of strong neutron entrainment.
nucl-thastro-ph.HEPRC(2019)·49 citations
03
Evidence for charm-bottom tetraquarks and the mass dependence of heavy-light tetraquark states from lattice QCD
Anthony Francis🇨🇭 · Renwick J. Hudspith🇨🇦 · Randy Lewis🇨🇦 · Kim Maltman🇨🇦
We continue our study of heavy-light four-quark states and find evidence from lattice QCD for the existence of a strong-interaction-stable $I (J^{P}) = 0 (1^{+})$ $u d c ˉ b ˉ$ tetraquark with mass in the range of 15 to 61 MeV below $D ˉ B^{*}$ threshold. Since this range includes the electromagnetic $D ˉ B γ$ decay threshold, current uncertainties do not allow us to determine whether such a state would decay electromagnetically, or only weakly. We also perform a study at fixed pion mass, with NRQCD for the heavy quarks, simulating $q q^{'} b ˉ^{'} b ˉ$ and $q q^{'} b ˉ^{'} b ˉ^{'}$ tetraquarks with $q, q^{'} = u d$ or $ℓ s$ and variable, unphysical $m_{b^{'}}$ in order to investigate the heavy mass-dependence of such tetraquark states. We find that the dependence of the binding energy follows a phenomenologically-expected form and that, though NRQCD breaks down before $m_{b^{'}} = m_{c}$ is reached, the results at higher $m_{b^{'}}$ clearly identify the $u d b ˉ^{'} b ˉ$ channel as the most likely to support a strong-interaction-stable tetraquark state at $m_{b^{'}} = m_{c}$ . This observation serves to motivate the direct $u d c ˉ b ˉ$ simulation. Throughout we use dynamical $n_{f} = 2 + 1$ ensembles with pion masses $m_{π} =$ 415, 299, and 164 MeV reaching down almost to the physical point, a relativistic heavy quark prescription for the charm quark, and NRQCD for the bottom quark(s).
↳ hep-lathep-phnucl-thPRD(2019)·140 citations
04
Prescaling and far-from-equilibrium hydrodynamics in the quark-gluon plasma
Aleksas Mazeliauskas🇩🇪 · Jürgen Berges🇩🇪
Prescaling is a far-from-equilibrium phenomenon which describes the rapid establishment of a universal scaling form of distributions much before the universal values of their scaling exponents are realized. We consider the example of the spatio-temporal evolution of the quark-gluon plasma explored in heavy-ion collisions at sufficiently high energies. Solving QCD kinetic theory with elastic and inelastic processes, we demonstrate that the gluon and quark distributions very quickly adapt a self-similar scaling form, which is independent of initial condition details and system parameters. The dynamics in the prescaling regime is then fully encoded in a few time-dependent scaling exponents, whose slow evolution gives rise to far-from-equilibrium hydrodynamic behavior.
↳ hep-phnucl-thPRL(2019)·82 citations
05
Consequences of broken axial symmetry in heavy nuclei -- an overview of the situation in the valley of stability
Eckart Grosse🇩🇪 · Arnd R. Junghans🇩🇪 · Jonathan N. Wilson🇫🇷
An overview on the various effects of axial symmetry breaking is presented for medium heavy and heavy nuclei covering the mass number range 70 < A <240. The discussion includes various observations for nuclei: level densities, spectroscopic features as energies and transition rates, ground state masses and finally the splitting of giant dipole resonances. Quadrupole moments and rates can be derived from models of triaxial rigid rotation or cranking for a given triaxiality parameters {\gamma}, but microscopic considerations are needed to predict these for each nucleus investigated. Respective predictions were made by recently made Hartree- Fock-Bogolyubov (HFB) calculations extended to arbitrary triaxiality by a generator coordinate method. In accord to these, various observations as reported in this overview demonstrate the importance of allowing a breaking of axial symmetry for heavy nuclei already in the valley of stability. Considering this breaking as indicated from the HFB approach surprisingly many experimental data are well described globally without the need for local fit parameters. In addition to these comparisons it will be shown that it is advantageous to consider c{\gamma}=cos(3{\gamma}) an indicator of axiality for heavy nuclei independent of their quadrupole moment.
↳ nucl-exastro-ph.SRnucl-thPhys.Scripta(2019)·2 citations
06
First Measurement of the Ar $(e, e^{'}) X$ Cross Section at Jefferson Lab
H. Dai🇺🇸 · M. Murphy🇺🇸 · V. Pandey🇺🇸 · D. Abrams🇺🇸 · D. Nguyen🇺🇸 · B. Aljawrneh🇺🇸 · S. Alsalmi🇺🇸 · A. M. Ankowski🇺🇸 · J. Bane🇺🇸 · S. Barcus🇺🇸 · O. Benhar🇮🇹 · V. Bellini🇮🇹 and 46 other authors
The success of the ambitious programs of both long- and short-baseline neutrino-oscillation experiments employing liquid-argon time-projection chambers will greatly rely on the precision with which the weak response of the argon nucleus can be estimated. In the E12-14-012 experiment at Jefferson Lab Hall A, we have studied the properties of the argon nucleus by scattering a high-quality electron beam off a high-pressure gaseous argon target. Here, we present the measured $^{40}$ Ar $(e, e^{'})$ double differential cross section at incident electron energy $E = 2.222$ ~GeV and scattering angle $θ = 15.54 1^{\circ}$ . The data cover a broad range of energy transfers, where quasielastic scattering and delta production are the dominant reaction mechanisms. The result for argon is compared to our previously reported cross sections for titanium and carbon, obtained in the same kinematical setup.
↳ nucl-exhep-exnucl-thPRC(2019)·49 citations
07
Matching the Quasi Meson Distribution Amplitude in RI/MOM scheme
Yu-Sheng Liu🇨🇳 · Wei Wang🇨🇳 · Ji Xu🇨🇳 · Qi-An Zhang🇨🇳 · Shuai Zhao🇨🇳 · Yong Zhao🇺🇸
The $x$ -dependence of light-cone distribution amplitude (LCDA) can be directly calculated from a quasi distribution amplitude (DA) in lattice QCD within the framework of large-momentum effective theory (LaMET). In this paper, we study the one-loop renormalization of the quasi-DA in the regularization-independent momentum subtraction (RI/MOM) scheme. The renormalization factor for the quasi parton distribution function can be used to renormalize the quasi-DA provided that they are implemented on lattice and in perturbation theory in the same manner. We derive the one-loop matching coefficient that matches quasi-DA in the RI/MOM scheme onto LCDA in the $MS$ scheme. Our result provides the crucial step to extract the LCDAs from lattice matrix elements of quasi-DAs.
↳ hep-phhep-latnucl-thPRD(2019)·46 citations

Affiliations

first authorsco-authorsvia INSPIRE

Tidal deformability with sharp phase transitions in (binary) neutron stars

Predicting the moment of inertia of pulsar J0737-3039A from Bayesian modeling of the nuclear equation of state

Evidence for charm-bottom tetraquarks and the mass dependence of heavy-light tetraquark states from lattice QCD

Prescaling and far-from-equilibrium hydrodynamics in the quark-gluon plasma

Consequences of broken axial symmetry in heavy nuclei -- an overview of the situation in the valley of stability

First Measurement of the Ar(e,e′)X Cross Section at Jefferson Lab

Matching the Quasi Meson Distribution Amplitude in RI/MOM scheme

Affiliations

First Measurement of the Ar $(e, e^{'}) X$ Cross Section at Jefferson Lab