Nuclear Theory·nucl-th

Monday·February 10, 2025

11 papers—6 primary·5 cross-listed

07
Establishing the vector-meson-exchange dominance for the short range interactions of light quarks
Bing-Song Zou🇨🇳
I give a brief comment on a recent study revealing the vector meson exchange (VME) dominant for the short range interactions between u/d quarks in the $N N$ , $D_{03}$ , and $D_{30}$ systems. The finding echoes nicely with an earlier study of hadron spectroscopy using a quark model with hidden local symmetry which also favors the VME dominant for the short range interactions of light quarks. The VME dominance for the short range interactions of light quarks gives a natural explanation of the empiric VME dominance for the interactions between hadrons containing light quarks.
↳ hep-phnucl-thSCPMA(2025)·3 citations
08
High-precision direct decay energy measurements of the electron-capture decay of $^{97}$ Tc
Zhuang Ge🇫🇮 · Tommi Eronen🇫🇮 · Vasile Alin Sevestrean🇷🇴 · Marlom Ramalho🇫🇮 · Ovidiu Nitescu🇷🇴 · Stefan Ghinescu🇷🇴 · Sabin Stoica🇷🇴 · Jouni Suhonen🇫🇮 · Antoine de Roubin🇧🇪 · Dmitrii Nesterenko🇫🇮 · Anu Kankainen🇫🇮 · Pauline Ascher🇫🇷 and 18 other authors
A direct measurement of the ground-state-to-ground-state electron-capture decay $Q$ ( $Q_{EC}$ ) value of $^{97}$ Tc has been conducted employing the high resolving power phase-imaging ion-cyclotron-resonance technique with the double Penning trap mass spectrometer JYFLTRAP. The resulting $Q_{EC}$ value for $^{97}$ Tc is 324.82(21) keV, exhibiting a precision approximately 19 times higher than the value adopted in the newest Atomic Mass Evaluation (AME2020) and differing by 1.2 $σ$ . Furthermore, by combining this refined $Q$ value with nuclear energy-level data for the decay-daughter $^{97}$ Mo, a potential ultra-low Q-value transition, possibly of allowed type, $^{97}$ Tc (9/2 $^{+}$ , ground state) $\to$ $^{97}$ Mo $^{*}$ (320(1) keV), was evaluated for future long-term neutrino-mass determination experiments. The ground-state-to-excited-state electron-capture decay $Q$ value ( $Q_{EC}^{*}$ ) of this transition was determined to be 4.8(10) keV, confirming it to be energetically allowed with a confidence level of exceeding 4 $σ$ . The captures of electrons occupying the L and higher shells for this transition are energetically allowed, giving a value of 2.0(10) keV for the closest distance of $Q_{EC}^{*}$ to the allowed binding energy of the L1 shell. To predict partial half-lives and energy-release distributions for this transition, the atomic self-consistent many-electron Dirac--Hartree--Fock--Slater method and the nuclear shell model have been employed. Dominant correction terms such as exchange and overlap corrections, as well as shake-up and shake-off effects, were included in the final results. Moreover, the normalized distribution of released energy in the electron-capture decay of $^{97}$ Tc to excited states of $^{97}$ Mo, is compared with that of $^{163}$ Ho, which is being used for electron-neutrino-mass determination.
↳ nucl-exnucl-thPRC(2025)·2 citations
09
Chiral effective model of cold and dense two-color QCD: The linear sigma model approach
Daiki Suenaga🇯🇵
This review is devoted to summarizing recent developments of the linear sigma model (LSM) in cold and dense two-color QCD (QC $_{2}$ D), in which lattice simulations are straightforwardly applicable thanks to the disappearance of the sign problem. In QC $_{2}$ D, both theoretical and numerical studies derive the presence of the so-called baryon superfluid phase at sufficiently large chemical potential ( $μ_{q}$ ), where diquark condensates govern the ground state. The hadron mass spectrum simulated in this phase shows that the mass of an iso-singlet ( $I = 0$ ) and $0^{-}$ state is remarkably reduced, but such a mode cannot be described by the chiral perturbation theory. Motivated by this fact, I invent the LSM constructed upon the linear representation of chiral symmetry, or more precisely the Pauli-Gürsey symmetry. Then, it is shown that my LSM successfully reproduces the low-lying hadron mass spectrum in a broad range of $μ_{q}$ simulated on the lattice. As applications of the LSM, topological susceptibility and sound velocity in cold and dense QC $_{2}$ D are evaluated to compare with lattice results. Besides, generalized Gell-Mann-Oakes-Renner relation and hardon mass spectrum in the presence of a diquark source are analyzed. I also introduce an extended version of the LSM incorporating spin- $1$ hadrons.
↳ hep-phhep-latnucl-thSymmetry(2025)·10 citations
10
Lattice perspectives on doubly heavy tetraquarks
Anthony Francis🇹🇼
Doubly heavy tetraquarks have emerged as new probes to study the heavy hadron spectrum. With the experimental observation of the $J^{P} = 1^{+}$ $T_{cc}^{+}$ , they pose a unique opportunity to bring together efforts in experiment, phenomenology, and lattice QCD. In lattice calculations they are accessible as ground states, unlike hidden flavor tetraquarks, and this enables accurate determinations of the scattering parameters alongside the binding energies of these tetraquarks. Today, lattice calculations firmly predict $J^{P} = 1^{+}$ $T_{bb}^{u d}$ and $T_{bb}^{u s}$ as QCD bound states, while recent studies approaching the $J^{P} = 1^{+}$ $T_{cc}^{u d}$ find it to be a virtual bound state at slightly non-physical input quark masses. Studies of the $J^{P} = 1^{+}$ $T_{b c}^{u d}$ are ongoing and a new focus area. In light of these developments the evolution of this field until this point is reviewed. Emphasis is put on the methods in lattice spectroscopy that enable a robust evaluation of the lattice studies gathered. They are further reviewed towards their limitations and achievements. Current challenges and opportunities are discussed, including possibilities to approach the left-hand cut in the scattering analysis of the charm candidates and towards understanding the structure of those including two bottom quarks.
↳ hep-lathep-phnucl-thPPNP(2025)·26 citations
11
Speed of sound in Kaluza-Klein Fermi gas
Anna Horváth🇭🇺 · Emese Forgács-Dajka🇭🇺 · Gergely Gábor Barnaföldi🇭🇺
A five-dimensional Kaluza-Klein spacetime model is considered, with one extra compactified spatial dimension. The equation of state of an electrically neutral, zero-temperature Fermi gas with a repulsive linear potential is described. From the equation of state, the speed of sound squared is calculated and shown for different model parameters. Its properties are studied from lower energies up to the conformal limit.
↳ hep-phastro-ph.HEnucl-thActa Phys.Polon.Supp.(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE

Establishing the vector-meson-exchange dominance for the short range interactions of light quarks

High-precision direct decay energy measurements of the electron-capture decay of 97Tc

Chiral effective model of cold and dense two-color QCD: The linear sigma model approach

Lattice perspectives on doubly heavy tetraquarks

Speed of sound in Kaluza-Klein Fermi gas

Affiliations

High-precision direct decay energy measurements of the electron-capture decay of $^{97}$ Tc