SearcharxivSearch

arXiv subjects

Bo Nan Zhang

Publications and source records attributed to Bo Nan Zhang.

3 recordsLinked to original sources

The possible $K^{*}Σ^{*}$ molecular state

Within the framework of the one-boson-exchange model, we systematically investigate the interaction between the vector meson $K^{*}$ and the baryon $Σ^{*}$ with the aim of exploring the possibility of forming hadronic molecular states. The $K^{*}Σ^{*}$ interaction potential is constructed from $ρ$, $ω$, and $π$ meson exchanges, and the nonrelativistic Schrödinger equation is solved using the Gaussian expansion method. The binding energies are calculated for different total angular momenta $J^{P}$ and isospin channels $I=1/2$ and $I=3/2$. Our results show that $S$--$D$ wave mixed $K^{*}Σ^{*}$ molecular states with $J^{P}=1/2^{-}$ can be formed only in the $I=3/2$ channel, while no bound state appears in the $I=1/2$ channel. In addition, the $S$--$D$ wave mixed states with $J^{P}=3/2^{-}$ and $J^{P}=5/2^{-}$ are also found to support bound-state solutions. For higher partial-wave states in our study, the binding mechanism mainly arises from the interplay between partial-wave mixing and non-central interactions. In particular, the $J^{P}=1/2^{+}$ channel does not support a bound state, as the meson-exchange interaction is predominantly repulsive. Our analysis further supports the interpretation of the experimentally observed $N(2250)$ and $Δ(2200)$ states as $K^{*}Σ^{*}$ molecular candidates, corresponding to $I=1/2,\ J^{P}=9/2^{-}$ and $I=3/2,\ J^{P}=7/2^{-}$, respectively.

hep-ph

Search for the $D^{*}\bar{D}^{*}$ Molecular State $X_{2}(4013)$ in $K^{-}p$ and $pp$ Collisions

Motivated by the interpretation of $X(3872)$ as a $D\bar{D}^{*}$ molecular state, heavy-quark spin symmetry predicts a spin-2 partner, $X_{2}(4013)$, which can be regarded as a $D^{*}\bar{D}^{*}$ molecule with quantum numbers $J^{PC} = 2^{++}$. Its experimental confirmation, however, remains elusive. In this work, we investigate the production mechanisms of $X_{2}(4013)$ in the reactions $K^{-}p \to Λ_{c}^{+} D_{s}^{-} X_{2}(4013)$ and $pp \to Λ_{c}^{+}Λ_{c}^{+} X_{2}(4013)$ within an effective Lagrangian framework. The production processes are modeled via $t$-channel $D/\bar{D}^{*}$ meson exchanges, while initial-state interactions (ISI) mediated by Pomeron and Reggeon exchanges are also taken into account. Our calculations indicate that the total cross sections can reach the pb level, suggesting that $X_{2}(4013)$ may be accessible at current and future experiments such as AMBER@CERN and LHCb. Inclusion of ISI enhances the cross sections by nearly one order of magnitude. The differential distributions show distinct angular behaviors for the two reactions: the $K^{-}p$ reaction exhibits a forward-peaked distribution, whereas the $pp$ reaction shows a dip near central angles. This study provides a quantitative theoretical benchmark for future experimental searches of $X_2(4013)$ and highlights the importance of initial-state interactions (ISI) in high-energy particle investigations.

hep-ph

Critical parameters of liquid-gas phase transition in thermal symmetric and asymmetric nuclear matter

The properties of critical parameters and phase diagram structure of liquid-gas phase transition are investigated in thermal symmetric and asymmetric nuclear matter with the covariant density functional (CDF) theory. Although uncertainty remains in predicting the critical parameters such as the critical temperature and pressure from various CDF functionals, several correlations are explored numerically and verified to be approximately linear between them. These correlations become worse when nuclear matter is more isospin asymmetric, resulting mainly from the effects induced by symmetry energy. By looking over the isospin dependence of the critical temperature, the role of the symmetry energy in LG transition properties of asymmetric matter is realized. The change of critical temperature with isospin asymmetry is found to be correlated well with and as a consequence could be constrained by the density slope of symmetry energy at saturation density. Then, the structure of phase diagram of thermal nuclear matter is analyzed carefully. It is revealed that the contribution from symmetry energy dominates the size of liquid-gas phase coexistence area. Moreover, the specific pattern of the phase diagram could be determined by the critical temperature at non-zero isospin asymmetry, illustrated from the correlations of the temperature with pressures at several characteristic points, paving the possible way to further explore the structure of liquid-gas phase diagram of thermal nuclear matter.

nucl-th