0000000000112588
AUTHOR
Hua-xing Chen
Looking for a hidden-charm pentaquark state with strangeness $S=-1$ from $\Xi^-_b$ decay into $J/\psi K^- \Lambda$
Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $\Xi^-_b\rightarrow J/\psi K^- \Lambda$ to search for the strangeness counterpart of the $P_c(4450)$. There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the finite state interactions in the meson-baryon system of strangeness $S=-2$ and isospin $I=1/2$ and of the $J/\psi\Lambda$. All these have been tested extensively. As a result, we provide a genuine prediction of the differential cross section where a strangeness hidden-charm pentaquark state, the counterpart…
THE ρ MESON IN FINITE VOLUME
We evaluate energy levels of the ππ system in the ρ channel in finite volume using chiral unitary theory. We investigate ππ phase shifts and ρ meson properties using Lattice QCD data with high precision. We also investigate the dependence on the π mass.
Substructure of Multiquark Hadrons (Snowmass 2021 White Paper)
In recent years there has been a rapidly growing body of experimental evidence for existence of exotic, multiquark hadrons, i.e. mesons which contain additional quarks, beyond the usual quark-antiquark pair and baryons which consist of more than three quarks. In all cases with robust evidence they contain at least one heavy quark Q=c or b, the majority including two heavy quarks. Two key theoretical questions have been triggered by these discoveries: (a) how are quarks organized inside these multiquark states -- as compact objects with all quarks within one confinement volume, interacting via color forces, perhaps with an important role played by diquarks, or as deuteron-like hadronic molec…
The pp->p Lambda K+ and pp->p Sigma0 K+ reactions with chiral dynamics
We report on a theoretical study of the pp->p Lambda K+ and pp->p Sigma0 K+ reactions near threshold using a chiral dynamical approach. The production process is described by single-pion and single-kaon exchange. The final state interactions of nucleon-hyperon, K-hyperon and K-nucleon systems are also taken into account. We show that our model leads to a fair description of the experimental data on the total cross section of the pp->p Lambda K+ and pp->p Sigma0 K+ reactions. We find that the experimental observed strong suppression of Sigma0 production compared to Lambda production at the same excess energy can be explained. However, ignorance of phases between some amplitudes does not allo…
$S$-wave $KK^*$ interaction in a finite volume and the $f_1(1285)$
Lattice QCD simulations provide a promising way to disentangle different interpretations of hadronic resonances, which might be of particular relevance to understand the nature of the so-called $XYZ$ particles. Recent studies have shown that in addition to the well-established naive quark model picture, the axial-vector meson $f_1(1285)$ can also be understood as a dynamically generated state built upon the $KK^*$ interaction. In this work, we calculate the energy levels of the $KK^*$ system in the $f_1(1285)$ channel in finite volume using the chiral unitary approach. We propose to calculate the loop function in the dimensional regularization scheme, which is equivalent to the hybrid appro…
Looking for a hidden-charm pentaquark state with strangeness $S=-1$ from $��^-_b$ decay into $J/��K^- ��$
Assuming that the recently observed hidden-charm pentaquark state, $P_c(4450)$, is of molecular nature as predicted in the unitary approach, we propose to study the decay of $��^-_b\rightarrow J/��K^- ��$ to search for the strangeness counterpart of the $P_c(4450)$. There are three ingredients in the decay mechanism: the weak decay mechanism, the hadronization mechanism, and the finite state interactions in the meson-baryon system of strangeness $S=-2$ and isospin $I=1/2$ and of the $J/����$. All these have been tested extensively. As a result, we provide a genuine prediction of the differential cross section where a strangeness hidden-charm pentaquark state, the counterpart of the $P_c(445…
A hidden-charm pentaquark state in $\Lambda^0_b \to J/\psi p \pi^-$ decay
We study here the $\Lambda_b^0 \to J/\psi p \pi^-$ reaction in analogy to the $\Lambda^0_b \to J/\psi p K^-$ one, and we note that in both decays there is a sharp structure (dip or peak) in the $J/\psi p$ mass distribution around $4450$ MeV, which is associated in the $\Lambda^0_b \to J/\psi p K^-$ experiment to an exotic pentaquark baryonic state, although in $\Lambda_b^0 \to J/\psi p \pi^-$ it shows up with relatively low statistics. We analyze the $\Lambda^0_b \to J/\psi p \pi^-$ interaction along the same lines as the $\Lambda^0_b \to J/\psi p K^-$ one, with the main difference stemming from the reduced Cabibbo strength in the former and the consideration of the $\pi^-p$ final state int…