Nuclear Theory·nucl-th

Friday·October 27, 2023

7 papers—3 primary·4 cross-listed

04
Maximal Mass Neutron Star as a Key to Superdense Matter Physics
D. D. Ofengeim · P. S. Shternin · T. Piran
We propose a universal approximation of the equation of state of superdense matter in neutron star (NS) interiors. It contains only two parameters, the pressure and the density at the center of the maximally massive neutron star. We demonstrate the validity of this approximation for a wide range of different types of equations of state, including both baryonic and hybrid models. Combined with recently discovered correlations of internal (density, pressure, and speed of sound at the center) and external (mass, radius) properties of a maximally massive neutron star, this approximation turns out to be an effective tool for determining the equation of state of superdense matter using astrophysical observations.
↳ astro-ph.HEastro-ph.SRnucl-thAstron.Lett.(2023)·9 citations
05
Further evidence for shape coexistence in $^{79}$ Zn $^{m}$ near doubly-magic $^{78}$ Ni
L. Nies (1 and 2)🇨🇭 · L. Canete (3 and 4)🇫🇮 · D. D. Dao (5)🇫🇷 · S. Giraud (6)🇫🇷 · A. Kankainen (3)🇫🇮 · D. Lunney (7)🇫🇷 · F. Nowacki (5)🇫🇷 · B. Bastin (6)🇫🇷 · M. Stryjczyk (3)🇫🇮 · P. Ascher (8)🇫🇷 · K. Blaum (9)🇩🇪 · R. B. Cakirli (10)🇹🇷 and 22 other authors
Isomers close to doubly-magic $_{28}^{78}$ Ni $_{50}$ provide essential information on the shell evolution and shape coexistence near the $Z = 28$ and $N = 50$ double shell closure. We report the excitation energy measurement of the $1/ 2^{+}$ isomer in $_{30}^{79}$ Zn $_{49}$ through independent high-precision mass measurements with the JYFLTRAP double Penning trap and with the ISOLTRAP Multi-Reflection Time-of-Flight Mass Spectrometer. We unambiguously place the $1/ 2^{+}$ isomer at 942(10) keV, slightly below the $5/ 2^{+}$ state at 983(3) keV. With the use of state-of-the-art shell-model diagonalizations, complemented with Discrete Non Orthogonal shell-model calculations which are used here the first time to interpret shape coexistence, we find low-lying deformed intruder states, similar to other $N = 49$ isotones. The $1/ 2^{+}$ isomer is interpreted as the band-head of a low-lying deformed structure akin to a predicted low-lying deformed band in $^{80}$ Zn, and points to shape coexistence in $^{79, 80}$ Zn similar to the one observed in $^{78}$ Ni. The results make a strong case for confirming the claim of shape coexistence in this key region of the nuclear chart.
↳ nucl-exnucl-thPRL(2023)·14 citations
06
The Four-Boson First-Excited State Near Two-Body Unitarity
Feng Wu🇺🇸 · T. Frederico🇧🇷 · R. Higa🇧🇷 · U. van Kolck🇫🇷
Near two-body unitarity, the three-boson system is characterized by an approximate discrete scale invariance manifest in a geometric tower of bound states (the Efimov effect). In the absence of a strong four-body force, the four-boson system has two states associated with each Efimov state, one very nearly unstable, the other several times deeper. We study correlations between the excited- and ground-state properties, such as binding energies and radii, up to next-to-leading order in an effective field theory for short-range forces. We obtain the parameters in these correlations from similar correlations arising from existing precise calculations based on short-range potentials. We also derive correlations among excited-state properties that emerge from the proximity of the state to the break-up threshold into a boson and a three-boson bound state, using an effective field theory for "halo" states.
↳ physics.atom-phnucl-thPRA(2024)·5 citations
07
Domain-wall Skyrmion phase in a rapidly rotating QCD matter
Minoru Eto🇯🇵 · Kentaro Nishimura🇯🇵 · Muneto Nitta🇯🇵
Based on the chiral perturbation theory at the leading order, we show the presence of a new phase in rapidly rotating QCD matter with two flavors, that is a domain-wall Skyrmion phase. Based on the chiral Lagrangian with a Wess-Zumino-Witten (WZW) term responsible for the chiral anomaly and chiral vortical effect, it was shown that the ground state is a chiral soliton lattice(CSL) consisting of a stack of $η$ -solitons in a high density region under rapid rotation. In a large parameter region, a single $η$ -soliton decays into a pair of non-Abelian solitons, each of which carries $SU (2)_{V} / U (1) ≃ C P^{1} ≃ S^{2}$ moduli as a consequence of the spontaneously broken vector symmetry $SU (2)_{V}$ . In such a non-Abelian CSL, we construct the effective world-volume theory of a single non-Abelian soliton to obtain a $d = 2 + 1$ dimensional $C P^{1}$ model with a topological term originated from the WZW term. We show that when the chemical potential is larger than a critical value, a topological lump supported by the second homotopy group $π_{2} (S^{2}) ≃ Z$ has negative energy and is spontaneously created, implying the domain-wall Skyrmion phase. This lump corresponds in the bulk to a Skyrmion supported by the third homotopy group $π_{3} [SU (2)] ≃ Z$ carrying a baryon number. This composite state is called a domain-wall Skyrmion, and is stable even in the absence of the Skyrme term. An analytic formula for the effective nucleon mass in this medium is obtained as $42 π f_{π} f_{η} / m_{π} \sim 1.21$ GeV with the decay constants $f_{π}$ and $f_{η}$ of the pions and $η$ meson, respectively, and the pion mass $m_{π}$ , which is surprisingly close to the nucleon mass in the QCD vacuum.
↳ hep-phhep-thnucl-thJHEP(2024)·32 citations

Affiliations

first authorsco-authorsvia INSPIRE

Maximal Mass Neutron Star as a Key to Superdense Matter Physics

Further evidence for shape coexistence in 79Znm near doubly-magic 78Ni

The Four-Boson First-Excited State Near Two-Body Unitarity

Domain-wall Skyrmion phase in a rapidly rotating QCD matter

Affiliations

Further evidence for shape coexistence in $^{79}$ Zn $^{m}$ near doubly-magic $^{78}$ Ni