We evaluate a hadronic molecule formed by a heavy meson and a nucleon respecting heavy quark symmetry. The tensor force of pion exchange potential plays a dominate role to produce an strong attraction in this system. Solving coupled channel Schrödinger equations for PN and P* N, we find many bound and resonant states with isospin I=0 while there are few resonances in I=1 state. The rich structures with I=0 indicate that the spectrum of heavy baryons near the threshold is influenced by the contributions from such hadron composite structures.
We cautiously review the treatment of pentaquark exotic baryons in chiral soliton models. We consider two examples and argue that any consistent and self-contained description must go beyond the mean field approximation that only considers the classical soliton and the canonical quantization of its (would-be) zero modes via collective coordinates.
A meson-baryon interaction in the charm $+1$, strangeness $-2$ and isospin $0$ sector is built from a t-channel vector meson exchange model employing effective Lagrangians. The implementation of coupled-channel unitarization in the s-wave scattering amplitudes gives rise to two structures that have similar masses and widths to those of the $Ω_c(3050)^0$ and $Ω_c(3090)^0$ states recently observed by the LHCb collaboration. A meson-baryon molecular interpretation of these resonances would assign their spin-parity to be $J^P=1/2^-$.
In this talk, we report on two recent studies of relativistic nucleon-nucleon and hyperon-nucleon interactions in covariant chiral perturbation theory, where they are constructed up to leading order. The relevant unknown low energy constants are fixed by fitting to the nucleon-nucleon and hyperon-nucleon scattering data. It is shown that these interactions can describe the scattering data with a quality similar to their next-to-leading order non-relativistic counterparts. These studies show that it is technically feasible to construct relativist baryon-baryon interactions, and in addition, aft…
Employing the covariant baryon chiral perturbation theory, we calculate the leading and next-to-leading order two-pion exchange (TPE) contributions to $NN$ interaction up to order $O(p^3)$. We compare the so-obtained $NN$ phase shifts with $2\leq L\leq 6$ and mixing angles with $2\leq J\leq6$ with those obtained in the nonrelativistic baryon chiral perturbation theory, which allows us to check the relativistic corrections to the medium-range part of $NN$ interactions. We show that the contributions of relativistic TPE are more moderate than those of the nonrelativistic TPE. The relativistic co…
By using the Nikiforov-Uvarov method, the hyper-radial Schrodinger equation is analytically solved, in which the real modified potential is employed at finite temperature and baryon chemical potential. The eigenvalue of energy and corresponding wave function are obtained in the isotropic and anisotropic media in hot and dense media. The present results show that the binding energy of nucleon and some heavy baryon decrease strongly in hot medium and decreases slightly with increasing baryon chemical potential. In addition, binding energy for each baryon is more bound in an anisotropic medium in…
Production of the pentaquark exotic baryon Xi_5 in bar{K} N scattering : bar{K} N -> K Xi_5 and bar{K} N -> K* Xi_5
本文在树水平上研究了bar{K} N -> KXi_5和bar{K} N -> K* Xi_5反应中新发现的五夸克奇异重子Xi_5的产生。我们考虑Xi_5的正宇称和负宇称。反应主要是由s-和u-通道过程，和产生的截面非常依赖于Xi_5的奇偶校验和形状因子的类型。我们已经看到，正宇称Xi_5的截面一般比负宇称Xi_5的大100倍左右。这种截面上的巨大差异将有助于对五夸克态重子的进一步研究。
The production of backward nucleons, $N(180^\circ)$, at $180^\circ$ in the nuclear target rest frame in proton-nucleus ($\mathrm{p}+A$) collisions is studied. The backward nucleons appearing outside of the kinematically allowed range of proton-nucleon ($\mathrm{p}+N$) reactions are shown to be due to secondary reactions of heavy baryonic resonances produced inside the nucleus. Baryonic resonances $R$ created in primary $\mathrm{p}+N$ reactions can change their masses and momenta due to successive collisions $R+N\rightarrow R +N $ with other nuclear nucleons. Two distinct mechanisms and kinemat…
We calculate the complete $T$-matrices of pion-nucleon ($πN$) scattering to the third order in heavy baryon SU(3) chiral perturbation theory. The baryon mass in the chiral limit $M_0$ and the low-energy constants are determined by fitting to phase shifts of $πN$ and the experimental octet-baryon masses simultaneously. By using these constants, we obtain the pion-nucleon sigma terms, $σ_{πN}=(34.57\pm 11.85)$ MeV. We also find that a very small strangeness content of the proton, $y \simeq 0$. The scattering lengths and the scattering volumes are predicted, which turn out to be in good agreement…
