Search arXivSearch

arXiv · 2407.19896

Meson-nucleus bound states in quark meson coupling model

Abstract

The formations of the $K(\bar{K})$, $D(\bar{D})$, and $B(\bar{B})$ meson-nucleus bound states in ${\rm{^{16}O}}$, ${\rm{^{40}Ca}}$, ${\rm{^{90}Zr}}$, ${\rm{^{197}Au}}$, and ${\rm{^{208}Pb}}$ nucleus are investigated using the quark meson coupling model. The model relies on a mean field description of non-overlapping nucleon bags bound by the self-consistent interactions of scalar ($σ$, $δ$) and vector ($ω$, $ρ$) mesons with the (anti)quarks inside the bags, which is further extended to explore the properties of nuclei. We estimate the meson-nucleus bound state energies by solving the Klein-Gordon equations with the real potentials calculated self-consistently within the model, using a coordinate space approach. The calculations are carried out for different nuclear interactions. The effects of Coulomb interaction are considered in the present study for the charged mesons. Our study indicates the formation of rather deeply bound $B$-mesic states at the very central region of the nuclei, compared to the $D$ and $K$ mesons, offering a more promising probe to explore subtle nuclear medium effects. The investigations of such bound states are of particular interest for the upcoming $\rm{\bar{P}ANDA}$ at FAIR, J-PARC-E29, and JLab experiments.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Arpita Mondal, Amruta Mishra. 2025-04-27. Meson-nucleus bound states in quark meson coupling model. https://arxiv.org/abs/2407.19896

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Chiral Symmetry and Its Restoration in QCD

Chiral symmetry is an approximate symmetry of QCD in the light-quark sector. Its spontaneous breaking in the QCD vacuum explains why the pion is anomalously light and why it plays a central role in nuclear physics, including the tensor component of the nuclear force and the saturation properties of nuclei. This article introduces chirality through the Dirac equation and shows how a fermion mass mixes left- and right-handed components, in close analogy with the Bogoliubov--Valatin theory of superconductivity. We then explain spontaneous symmetry breaking, the Nambu--Goldstone theorem, and the role of the chiral condensate as an order parameter. The axial $U(1)_A$ anomaly and its consequences, especially for the $η'$ meson, are discussed. Chiral effective models, including Nambu--Jona-Lasinio-type models, linear sigma models with anomaly terms, and parity-doublet models for baryons, are reviewed as tools for describing hadron properties and the equation of state of dense matter. Finally, we discuss how chiral symmetry may be partially restored at finite temperature and/or baryon density, and summarize experimental probes such as deeply bound pionic atoms, dilepton production in relativistic heavy-ion collisions, $η'$-mesic nuclei, and baryonic observables.

nucl-th

Time-evolution formalism in the complex scaling method: Application to the two-proton decay of $^{6}$Be

We apply our complex-scaled time-evolution operator to the two-proton decay of $^{6}$Be. The nucleus is described as an $α+p+p$ three-body system with explicit Jacobi-coordinate rearrangement and the realistic Argonne $v8'$ NN interaction for the proton-proton subsystem. Starting from a confined initial wave packet, the decay dynamics are described by expansion over the complex-scaled eigenstates of the final Hamiltonian. The decay width extracted from the late-time survival probability agrees closely with that obtained from the CSM resonance pole. The time-dependent densities in different Jacobi coordinates reveal complementary aspects of the evolving three-body geometry, while the spin-singlet component remains dominant during the decay. In particular, the correlated two-proton configuration persists even in the presence of the strong short-range repulsion of the realistic NN interaction. These results demonstrate the applicability of the complex-scaled time-evolution framework to explicit three-body decay dynamics and provide a consistent description of the decay width, spatial evolution, and spin correlations of $^{6}$Be.

nucl-th

Spin-One Secondary Pairing in Two-Flavor Color Superconductivity: Spinful Relativistic Superfluidity and Anomaly Matching

We study secondary pairing in the two-flavor color-superconducting (2SC) phase, where the residual ungapped quarks form a same-chirality $J^P=1^+$ condensate driven by an attractive instanton-induced interaction. We determine its symmetry realization, quasiparticle structure, anomaly matching, and low-energy effective theory. The pairing gap is necessarily nodal; in particular, the complex axial state has two point nodes and realizes a spinful relativistic superfluid. This state preserves the full chiral symmetry ${\rm SU}(2)_{\rm L}\times{\rm SU}(2)_{\rm R}$ while breaking the modified baryon-number symmetry ${\rm U}(1)_{\tilde{\rm B}}$ and spatial rotations, with rotations about the nodal axis locked to the condensate phase. This locking gives rise to a Berry term, the Mermin-Ho relation, and a type-B orientational Nambu-Goldstone mode in addition to the superfluid phonon. We also show how anomaly matching is reorganized by secondary pairing: the perturbative mixed ${\rm SU}(2)_{\rm L,R}^2{\rm U}(1)_{\tilde{\rm B}}$ anomaly is realized by a Wess-Zumino coupling of the superfluid phonon, whereas the ${\rm SU}(2)_{\rm L}$ and ${\rm SU}(2)_{\rm R}$ Witten anomalies are carried by the point-node Bogoliubov-de Gennes flavor doublets. The resulting theory provides a concrete dense-QCD realization of a spinful relativistic superfluid with nodal fermions required by anomaly matching.

nucl-th