Nuclear Theory·nucl-th

Thursday·March 7, 2024

11 papers—4 primary·7 cross-listed

05
Constraining the equation of state in neutron-star cores via the long-ringdown signal
Christian Ecker · Tyler Gorda · Aleksi Kurkela · Luciano Rezzolla
Multimessenger signals from binary neutron star (BNS) mergers are promising tools to infer the largely unknown properties of nuclear matter at densities that are presently inaccessible to laboratory experiments. The gravitational waves (GWs) emitted by BNS merger remnants, in particular, have the potential of setting tight constraints on the neutron-star equation of state (EOS) that would complement those coming from the late inspiral, direct mass-radius measurements, or ab-initio dense-matter calculations. To explore this possibility, we perform a representative series of general-relativistic simulations of BNS systems with EOSs carefully constructed so as to cover comprehensively the high-density regime of the EOS space. From these simulations, we identify a novel and tight correlation between the ratio of the energy and angular-momentum losses in the late-time portion of the post-merger signal, i.e., the ``long ringdown'', and the properties of the EOS at the highest pressures and densities in neutron-star cores. When applying this correlation to post-merger GW signals, we find a significant reduction of the EOS uncertainty at densities several times the nuclear saturation density, where no direct constraints are currently available. Hence, the long ringdown has the potential of providing new and stringent constraints on the state of matter in neutron stars in general and, in particular, in their cores.
↳ astro-ph.HEgr-qchep-phnucl-thNature Commun.(2025)·32 citations
06
Dynamical tidal response of non-rotating relativistic stars
Abhishek Hegade K. R.🇺🇸 · Justin L. Ripley🇺🇸 · Nicolás Yunes🇺🇸
Accurately modeling the tidal response of neutron stars is crucial to connecting gravitational wave observations of binaries to ultra-dense nuclear physics. Most current models of the tidal response of relativistic stars either assume a static response model, or use phenomenological models inspired by Newtonian gravity. In this work, we present a general formalism for computing the linear dynamical tidal response function of relativistic, spherically symmetric stars. Our formalism incorporates stratification due to thermal and chemical imbalances, allowing one to study the effects of g modes on the tidal response function. We also describe how to incorporate sources of dissipation due to shear and bulk viscosity. To showcase the utility of our approach, we present several applications for polytropic stars in general relativity. We show how our formalism can capture the dynamical tidal resonance due to the f and g modes of inviscid stars and explore the sensitivity of the dynamical tidal response to the compactness of the star. We also compute the dissipative tidal deformability due to bulk and shear viscous dissipation assuming a simple viscous profile for the bulk and shear viscosity.
↳ gr-qcastro-ph.HEhep-thnucl-thPRD(2024)·60 citations
07
Quark Counting, Drell-Yan West, and the Pion Wave Function
Mary Alberg🇺🇸 · Gerald A. Miller🇺🇸
The relation between the pion's quark distribution function, $q (x)$ , its light-front wave function, and the elastic charge form factor, $F (Δ^{2})$ is explored. The square of the leading-twist pion wave function at a special probe scale, $ζ_{H}$ , is determined using models and Poincare covariance from realistic results for $q (x)$ . This wave function is then used to compute form factors with the result that the Drell-Yan-West and quark counting relationships are not satisfied. A new relationship between $q (x)$ and $F (Δ^{2})$ is proposed.
↳ hep-phnucl-exnucl-thPRC(2024)·5 citations
08
Mass and decay width of $T_{ccs}$ from symmetries
Mitsuru Tanaka🇯🇵 · Yasuhiro Yamaguchi🇯🇵 · Masayasu Harada🇯🇵
We analyze the mass and width of the doubly heavy tetraquark $T_{ccs}$ composed of a heavy diquark and a light-quark cloud with strangeness with assuming that a color antitriplet heavy diquark is a dominant component of the doubly charmed tetraquarks $T_{cc}$ and $T_{ccs}$ . We construct an effective Lagrangian for masses of heavy hadrons based on the superflavor symmetry between the doubly heavy tetraquarks and the singly heavy baryons by including the terms that simultaneously break the heavy-quark and light-flavor symmetries, and predict the mass of $T_{ccs}$ as $M (T_{ccs}) = 4047 \pm 11$ \,MeV. The comparison of this prediction with future experimental observation will give a clue to understand the color structure of the heavy diquark. We also predict the mass of $Ω_{cc}$ as $M (Ω_{cc}) = 370 6_{- 15}^{+ 14}$ MeV. We next calculate the decay width of $T_{ccs}$ , based on solely the light-flavor symmetry, as $Γ (T_{ccs}) = 42 \pm 24$ \,MeV.
↳ hep-phnucl-thPRD(2024)·8 citations
09
Neutron radius determination of 133Cs and its impact on the interpretation of CEvNS-CsI measurement
Y. Huang🇨🇳 · S. Y. Xia🇨🇳 · Y. F. Li🇨🇳 · X. L. Tu🇨🇳 · J. T. Zhang🇨🇳 · C. J. Shao🇨🇳 · K. Yue🇨🇳 · P. Ma🇨🇳 · Y. F. Niu🇨🇳 · Z. P. Li🇨🇳 · Y. Kuang🇨🇳 · X. Q. Liu🇨🇳 and 7 other authors
Proton- $^{133}$ Cs elastic scattering at low momentum transfer is performed using an in-ring reaction technique at the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou. Recoil protons from the elastic collisions between the internal H $_{2}$ -gas target and the circulating $^{133}$ Cs ions at 199.4 MeV/u are detected by a silicon-strip detector. The matter radius of $^{133}$ Cs is deduced by describing the measured differential cross sections using the Glauber model. Employing the adopted proton distribution radius, a point-neutron radius of 4.86(21) fm for $^{133}$ Cs is obtained. With the newly determined neutron radius, the weak mixing angle sin $^{2} θ_{W}$ is independently extracted to be 0.227(28) by fitting the coherent elastic neutrino-nucleus scattering data. Our work limits the sin $^{2} θ_{W}$ value in a range smaller than the ones proposed by the previous independent approaches, and would play an important role in searching new physics via the high precision CE $ν$ NS-CsI cross section data in the near future.
↳ nucl-exnucl-thPLB(2024)·9 citations
10
Do not forget the electrons: Extending moderately-sized nuclear networks for multidimensional hydrodynamic codes
Domingo García-Senz · Rubén M. Cabezón · Moritz Reichert · Axel S. Lechuga · José A. Escartín · Athanasios Psaltis · Almudena Arcones · Friedrich-Karl Thielemann
We present here an extended nuclear network, with 90 species, designed for being coupled with hydrodynamic simulations, which includes neutrons, protons, electrons, positrons, and the corresponding neutrino and anti-neutrino emission. This network is also coupled with temperature, making it extremely robust and, together with its size, unique of its kind. The inclusion of electron captures on free protons makes the network very appropriate for multidimensional studies of Type Ia supernova explosions, especially when the exploding object is a massive white dwarf. The results obtained with the proposed medium-sized network compare fairly well, to a few percent, with those computed with the extended network WinNet (> 2000 isotopes) in scenarios reproducing the gross physical conditions of current Type Ia supernova explosion models. In those cases where the carbon and oxygen fuel ignites at high density, the high-temperature plateau typical of the nuclear statistical equilibrium regime is well defined and stable, allowing large integration time steps. We show that the inclusion of electron captures on free protons substantially improves the estimation of the electron fraction of the mixture. Therefore, the pressure is better determined than in networks where electron captures are excluded, which will ultimately lead to more reliable hydrodynamic models. Explosive combustion of helium at low density, occurring near the surface layer of a white dwarf, is also better described with the proposed network, which gives nuclear energy generation rates much closer to WinNet than typical reduced alpha networks.
↳ astro-ph.SRastro-ph.HEastro-ph.IMnucl-thAstron.Astrophys.(2024)·2 citations
11
An assessment of $Υ$ -states above $B B ˉ$ -threshold using a constituent-quark-model based meson-meson coupled-channels framework
P. G. Ortega🇪🇸 · D. R. Entem🇪🇸 · F. Fernández🇪🇸 · J. Segovia🇪🇸
The $Υ (10753)$ state has been recently observed by the Belle and Belle~II collaborations with enough global significance to motivate an assessment of the high-energy spectrum usually predicted by any reasonable \emph{naïve} quark model. In the framework of a constituent quark model which satisfactorily describes a wide range of properties of conventional hadrons containing heavy quarks, the quark-antiquark and meson-meson degrees of freedom have been incorporated with the goal of elucidating the influence of open-bottom meson-meson thresholds into the $Υ$ states whose masses are within the energy range of the $Υ (10753)$ 's mass. It is well known that such effects could be relevant enough as to generate dynamically new states and thus provide a plausible explanation of the nature of the $Υ (10753)$ state. In particular, we have performed a coupled-channels calculation in which the bare states $Υ (4 S)$ , $Υ (3 D)$ , $Υ (5 S)$ and $Υ (4 D)$ are considered together with the threshold channels $B B ˉ$ , $B B ˉ^{*}$ , $B^{*} B ˉ^{*}$ , $B_{s} B ˉ_{s}$ , $B_{s} B ˉ_{s}^{*}$ and $B_{s}^{*} B ˉ_{s}^{*}$ . Among the results we have described, the following conclusions are of particular interest: (i) a richer complex spectrum is gained when thresholds are present and bare bound states are sufficiently non-relativistic; (ii) those poles obtained in the complex energy plane do not have to appear as simple peaks in the relevant cross sections; and (iii) the $Υ (10750)$ candidate is interpreted as a dressed hadronic resonance whose structure is an equally mixture of a conventional $b b ˉ$ state and $B^{*} B ˉ^{*}$ molecule.
↳ hep-phhep-exhep-latnucl-ex+1PRD(2024)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE

Constraining the equation of state in neutron-star cores via the long-ringdown signal

Dynamical tidal response of non-rotating relativistic stars

Quark Counting, Drell-Yan West, and the Pion Wave Function

Mass and decay width of Tccs​ from symmetries

Neutron radius determination of 133Cs and its impact on the interpretation of CEvNS-CsI measurement

Do not forget the electrons: Extending moderately-sized nuclear networks for multidimensional hydrodynamic codes

An assessment of Υ-states above BBˉ-threshold using a constituent-quark-model based meson-meson coupled-channels framework

Affiliations

Mass and decay width of $T_{ccs}$ from symmetries

An assessment of $Υ$ -states above $B B ˉ$ -threshold using a constituent-quark-model based meson-meson coupled-channels framework