In-medium mass shifts of $B_c^{(*)}, B_s^{(*)}$ and $D_s^{(*)}$ mesons

TL;DR

The paper addresses in-medium Lorentz-scalar mass shifts of two-flavored heavy mesons ($B_c^{(*)}, B_s^{(*)}, D_s^{(*)}$) in symmetric nuclear matter by computing lowest-order one-loop self-energies using a flavor-SU(5) Lagrangian, with in-medium intermediate-state masses supplied by the QMC framework. It finds negative mass shifts for all studied mesons at nuclear matter density $ ho_0$, with magnitudes dependent on the loop content and the regulator cutoff $oldsymbol{\Lambda}$, illustrating substantial in-medium modifications driven by gluon-mediated interactions. The results provide quantitative estimates across several cutoffs (2000–6000 MeV) and densities (up to a few times $ ho_0$), highlighting strong potential implications for meson-nucleus bound states and motivating future work on in-medium widths and bound-state phenomenology. Overall, the work advances understanding of how heavy mesons interact with the nuclear medium and lays groundwork for exploring bound-state formation and experimental signatures in nuclear environments.

Abstract

We present our predictions for the Lorentz scalar mass shifts of two-flavored heavy mesons, $B_c^{(*)}, B_s^{(*)}$ and $D_s^{(*)}$ in symmetric nuclear matter. The in-medium mass shifts are estimated by evaluating the lowest order one-loop self-energies of the mesons based on a flavor-SU(5) effective Lagrangian approach. In-medium properties necessary for the estimates are calculated by the quark-meson coupling (QMC) model. The enhanced self-energies of the mesons in symmetric nuclear matter relative to those in free space, yield the negative mass shifts of these mesons.

Figures (5)

• Figure 1: Meson self-energy diagrams for mesons $B_c$ [(a) and (a')], $B_s$ [(b) and (b')], $D_s$ [(c) and (c')], $B_{c}^{*}$ [(d)], $B_{s}^{*}$ [(e)], and $D_{s}^{*}$ [(f)], included in the present study.
• Figure 2: $B$ and $B^*$ (top), $D$ and $D^*$ (middle) and $K$ and $K^*$ (middle) meson Lorentz-scalar effective masses in symmetric nuclear matter versus baryon density ($\rho_B/\rho_0$), calculated by the QMC model.
• Figure 3: The total ($B^*D$ + $BD^*$) loop contribution for the in-medium $B_c$ mass shift (upper panel) and that of the $BD$ loop for $B_c^*$ (lower panel), versus baryon density ($\rho_B/\rho_0$) for five different cutoff mass values $\Lambda$.
• Figure 4: The total ($B^*K$+$BK^*$) loop contribution for the in-medium $B_s^0$ mass shit (upper panel) and that of the $BK$ loop for the $B_s^* \equiv B_s^{0 *}$ (lower panel), versus baryon density ($\rho_B/\rho_0$) for five different cutoff mass values $\Lambda$.
• Figure 5: The total ($D^*K$ + $DK^*$) loop contribution for the in-medium $D_s$ mass shift (upper panel) and that of the $DK$ loop for the $D_s^*$ (lower panel), versus baryon density for five different cutoff mass values $\Lambda$.