Nuclear Theory·nucl-th

Monday·December 13, 2021

11 papers—5 primary·6 cross-listed

01
[Submitted on 10 Dec 2021]
Hot neutron stars and their equation of state
Jin-Biao Wei · G. F. Burgio · Ad. R. Raduta · H.-J. Schulze
A set of microscopic, covariant density-functional, and non-relativistic Skyrme-type equations of state is employed to study the structure of purely nucleonic neutron stars at finite temperature. After examining the agreement with presently available astrophysical observational constraints, we find that the magnitude of thermal effects depends on the nucleon effective mass as well as on the stiffness of the cold equation of state. We evidence a fairly small but model-dependent effect of finite temperature on stellar stability that is correlated with the relative thermal pressure inside the star.
Comments:
10 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2112.05323 [pdf]
PRC(2021)·24 citations
02
[Submitted on 10 Dec 2021]
Cooper quartet correlations in infinite symmetric nuclear matter
Yixin Guo🇯🇵 · Hiroyuki Tajima🇯🇵 · Haozhao Liang🇯🇵
We investigate the quartet correlations in four-component fermionic systems at the thermodynamic limit within a variational many-body theory. The Bardeen-Cooper-Schrieffer (BCS)-type variational wave function is extended to the systems with the coexistence of pair and quartet correlations at zero temperature. Special attention is paid to the application of the present framework to an alpha-particle condensation in symmetric nuclear matter, where the coexistence of deuteron and alpha condensations is anticipated. We also discuss how physical properties, such as quasiparticle dispersion, can be modified by the pair and quartet correlations and show a hierarchical structure of in-medium cluster formations in infinite nuclear matter. The present results may also contribute to the interdisciplinary understanding of fermionic condensations beyond the BCS paradigm in many-body systems.
Comments:
11 pages, 2 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)
arXiv:
2112.05349 [pdf]
PRC(2022)·15 citations
03
[Submitted on 10 Dec 2021]
Hybrid stars from a constrained equation of state
Márcio Ferreira🇵🇹 · Renan Câmara Pereira🇵🇹 · Constança Providência🇵🇹
We determine, within a meta-model, the properties of the nuclear matter equation of state (EoS) that allow for a phase transition to deconfinement matter. It is shown that the properties that define the isoscalar channel are the ones that are affected, in particular, a phase transition implies much larger values of the skewness and kurtosis. The effect of multi-quark interaction channels in the description of the quark phase in hybrid stars is also studied. NS properties, such as the mass and radius of the quark core, show an interplay dependence between the 8-quark vector and the 4-quark isovector-vector interactions. We show that low mass NS, $M \sim 1.4 M_{⊙}$ , may already contain a quark core, and satisfy all existing NS observational constraints. We discuss the strangeness content of the quark core and its influence on the speed of sound.
Comments:
8 pages, 5 figures, Contribution to the Virtual Tribute to Quark Confinement and the Hadron Spectrum 2021 conference proceedings (vConf21)
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2112.05546 [pdf]
EPJ Web Conf.(2022)·2 citations
04
[Submitted on 10 Dec 2021]
Determination of the symmetry energy from the neutron star equation of state
Pedro Barata de Tovar🇵🇹 · Márcio Ferreira🇵🇹 · Constança Providência🇵🇹
We analyze the uncertainties introduced in the determination of the neutron star matter proton fraction, in a range of densities close to the saturation density, if the cold $β$ -equilibrium neutron star matter equation of state (EoS) is known. In particular, we discuss the effect of neglecting the muon contribution and of considering that the energy density of nuclear matter is well described by taking only terms until second order in the proton-neutron asymmetry. It is shown that two types of uncertainties may be associated with the extraction of the symmetry energy from the $β$ -equilibrium equation of state: an overestimation if terms above the parabolic approximation on the asymmetry parameter are neglected, or an underestimation if the muon contribution is not considered. The effect of the uncertainty on the symmetric nuclear matter EoS on the determination of the proton fraction is discussed. It could be shown that the neutron star mass-radius curve is sensitive to the parabolic approximation on the asymmetry parameter.
Comments:
13 pages, 8 figures, published version
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2112.05551 [pdf]
PRD(2021)·23 citations
05
[Submitted on 10 Dec 2021]
$β^{-} p$ and $β^{-} α$ decay of the $^{11}$ Be neutron halo ground state
J. Okołowicz🇵🇱 · M. Płoszajczak🇫🇷 · W. Nazarewicz🇺🇸
Beta-delayed proton emission from the neutron halo ground state of $^{11}$ Be raised much attention due to the unusually high decay rate. It was argued that this may be due to the existence of a resonance just above the proton decay threshold. In this Letter, we use the lenses of real-energy continuum shell model to describe several observables including the Gamow-Teller rates for the $β^{-}$ -delayed $α$ and proton decays, and argue that, within our model, the large $β^{-} p$ branching ratio cannot be reconciled with other data.
Comments:
5 pages, 3 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2112.05622 [pdf]
J.Phys.G(2022)·16 citations
06
[Submitted on 8 Dec 2021] (cross-list from cond-mat.quant-gas)
Vortices in spin-0 superfluids carry magnetic flux
Aleksey Cherman🇺🇸 · Theodore Jacobson🇺🇸 · Srimoyee Sen🇺🇸 · Laurence G. Yaffe🇺🇸
Vortices in spin- $0$ superfluids generically carry magnetic fields inside their cores, so that even neutral superfluid vortices may be thought of as magnetic flux tubes. We give a systematic analysis of this `vortex magnetic effect' using effective field theory, clarifying earlier literature on the subject. Our analysis shows that in superfluid Helium- $4$ the vortex magnetic effect may be large enough to be experimentally detectable.
Comments:
v2: corrected an error which does not change the conclusion, improved exposition
Subjects:
Quantum Gases (cond-mat.quant-gas); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2112.04595 [pdf]
PRB(2023)·1 citation
07
[Submitted on 9 Dec 2021] (cross-list from hep-ph)
The LPM effect in sequential bremsstrahlung: analytic results for sub-leading (single) logarithms
Peter Arnold🇺🇸 · Tyler Gorda🇩🇪 · Shahin Iqbal🇨🇳
Consider the in-medium splitting $g \to g g$ of a very high-energy gluon traversing a QCD medium, accounting for the Landau-Pomeranchuk-Migdal (LPM) effect. It has been known for some time that soft radiative corrections to that splitting generate a double-log correction to the splitting rate, whose effects can be absorbed into running of the medium parameter $q^$ describing the rate of transverse momentum kicks to high-energy particles due to small-angle scattering from the medium. Less has been known about sub-leading, single logarithms in this context. In this paper, we find analytic formulas for those single logs (with various caveats and clarifications).
Comments:
54 pages, 20 figures. Chages from v1 are superficial -- mostly a slight expansion of the introduction and conclusion
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.05161 [pdf]
JHEP(2022)·30 citations
08
[Submitted on 9 Dec 2021] (cross-list from hep-lat)
Three-particle scattering amplitudes from lattice QCD
Fernando Romero-López🇺🇸
Lattice QCD already offers the possibility of extracting three-hadron scattering quantities from first principles. In the last few years, significant progress has been achieved in developing and applying the finite-volume three-body formalism. The formalism is now able to treat physically relevant systems of three mesons, including those with resonances, as well as three-body decays. In this talk, I will review the state of the art, and comment on recent applications to lattice QCD data for systems of three pions and kaons.
Comments:
Invited plenary talk at the Hadron 2021 conference. 9 pages, 8 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.05170 [pdf]
Rev.Mex.Fis.Suppl.(2022)·13 citations
09
[Submitted on 10 Dec 2021] (cross-list from hep-lat)
Non-perturbative thermal QCD at all temperatures: the case of mesonic screening masses
Mattia Dalla Brida🇨🇭 · Leonardo Giusti🇮🇹 · Tim Harris🇬🇧 · Davide Laudicina🇮🇹 · Michele Pepe🇮🇹
We present a strategy based on the step-scaling technique to study non-perturbatively thermal QCD up to very high temperatures. As a first concrete application, we compute the flavour non-singlet meson screening masses at 12 temperatures covering the range from $T \sim 1$ GeV up to $\sim 160$ GeV in the theory with three massless quarks. The calculation is carried out by Monte Carlo simulations on the lattice by considering large spatial extensions in order to have negligible finite volume effects. For each temperature we have simulated 3 or 4 values of the lattice spacing, so as to perform the continuum limit extrapolation with confidence at a few permille accuracy. Chiral symmetry restoration manifests itself in our results through the degeneracy of the vector and the axial vector channels and of the scalar and the pseudoscalar ones. In the entire range of temperatures explored, the meson screening masses deviate from the free theory result, $2 π T$ , by at most a few percent. These deviations, however, cannot be explained by the known leading term in the QCD coupling constant $g$ up to the highest temperature, where other contributions are still very relevant. In particular the vector-pseudoscalar mass splitting turns out to be of $O (g^{4})$ in the entire range explored, and it remains clearly visible up to the highest temperature, where the two screening masses are still significantly different within our numerical precision. The pattern of different contributions that we have found explains why it has been difficult in the past to match non-perturbative lattice results at $T \sim 1$ GeV with the analytic behaviour at asymptotically high temperatures.
Comments:
32 pages, 5 figures. V2 typos corrected, minor modifications in the text, version to appear on JHEP
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.05427 [pdf]
JHEP(2022)·50 citations
10
[Submitted on 10 Dec 2021] (cross-list from hep-ph)
Gluon and valence quark distributions for the pion and kaon in nuclear matter
Parada T.P. Hutauruk🇰🇷 · Seung-il Nam🇰🇷
In this paper we study the gluon and valence quark distributions in the pion and kaon in nuclear medium for various nuclear densities as well as in vacuum within the Nambu--Jona-Lasinio (NJL) model with the help of the proper-time regularization scheme which simulates a confinement of QCD. The nuclear medium effect is also determined in the same model for the symmetric nuclear matter. We then analyze the gluon and valence quark distributions for the bound pion and kaon in symmetric nuclear matter as well as those in vacuum. We find that the valence quark and gluon distributions in vacuum have relatively good agreements with the experimental data, the lattice QCD simulations, and the JAM Monte-Carlo (MC) global fit QCD analysis. Evolving to the higher factorization scale $Q =$ 4 GeV, the in-medium gluon and valence-quark distributions of the pion for various nuclear densities are turned out to be almost unchanged in comparison to the vacuum cases. On the contrary, for the kaon, they increase significantly with respect to the densities. Finally, we find that the vacuum gluon distribution for the kaon is smaller than that for the pion, which is consistent with other theoretical predictions. This feature holds for the in-medium gluon distribution in the nuclear density up to the saturation density.
Comments:
10 pages, 15 figures, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.05435 [pdf]
PRD(2022)·18 citations
11
[Submitted on 10 Dec 2021] (cross-list from hep-lat)
First Lattice QCD Study of Proton Twist-3 GPDs
Shohini Bhattacharya🇸🇪 · Krzysztof Cichy🇺🇸 · Martha Constantinou🇵🇱 · Jack Dodson🇫🇷 · Andreas Metz🇸🇪 · Aurora Scapellato🇺🇸 · Fernanda Steffens🇩🇪
We present first results on selected twist-3 quark GPDs using the quasi-distribution method. This approach relates lattice QCD data and light-cone distribution functions using Large Momentum Effective Theory (LaMET). We calculate quark-antiquark correlators of boosted nucleons coupled to non-local operators with vector and axial Dirac structure, which is transverse to the momentum boost. We use three values of the momentum boost, namely 0.83, 1.25, 1.67 GeV. The GPDs are defined in the symmetric (Breit) frame, which we implement here with 4-vector momentum transfer squared of 0, 0.69 and 1.39 GeV 2 , all at zero skewness. The calculation is performed using one ensemble of two degenerate light, a strange and a charm quark ( $N_{f}$ = 2 + 1 + 1) of maximally twisted mass fermions with a clover term, corresponding to a pion mass of 260 MeV.
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2112.05538 [pdf]
PoS(2022)·25 citations

Affiliations

first authorsco-authorsvia INSPIRE