Related papers: Understanding Pentaquark States in QCD
By using QCD Sum Rules, we found that the charged hidden charm tetraquark $[c u][\bar{c} \bar{d}]$ states with $ J^P = 1^-$ and $ 2^+$, which are possible quantum numbers of the newly observed charmonium-like resonance $Z_c(4025)$, have…
Inspired by the LHCb's observations of hidden-charm $P_{c(s)}$ states, we study their hidden-strange analogues $P_s$ states in both $[udu][\bar ss]$ and $[uds][\bar su]$ configurations. We investigate the $P_s$ pentaquark states in…
The penta-quark(5Q) Theta^+(1540) is studied in anisotropic lattice QCD with renormalized anisotropy a_s/a_t=4 for a high-precision measurement. Both the positive and the negative parity 5Q baryons are studied using a non-NK type…
We perform a theoretical analysis of the $\Lambda_b \to J/\psi K^- p$ reaction from where a recent LHCb experiment extracts a $\Lambda(1405)$ contribution in the $K^- p$ spectrum close to threshold and two baryon states of hidden charm in…
I review some selected aspects of the phenomenology of multiquark states discovered in high energy experiments. They have four valence quarks (called tetraquarks) and two of them are found to have five valence quarks (called pentaquarks),…
The LHCb collaboration has recently announced the discovery of two hidden-charm pentaquark states with also strange quark content, $P_{cs}(4338)$ and $P_{cs}(4459)$; its analysis points towards having both hadrons isospin equal to zero and…
The spectra of some 0++ four-quark states, which are composed of \bar qq pairs, are calculated in QCD. The light four-quark states are calculated using the traditional sum rules while four-quark states containing one heavy quark are…
We investigate the mass spectrum of the pentaquark baryon ($ udud \bar s $) in quenched lattice QCD with exact chiral symmetry. Using 3 different interpolating operators for $ \Theta $, we measure the $ 3 \times 3 $ correlation matrix and…
We consider a $[ud]^2\bar{s}$ current in the QCD sum rule framework to study the mass of the recently observed pentaquark state $\Theta^+(1540)$, obtaining good agreement with the experimental value. We also study the mass of the pentaquark…
Some hadrons have the exotic quantum numbers that the traditional $\bar q q$ mesons and $qqq$ baryons can not reach, such as $J^{PC} = 0^{--}/0^{+-}/1^{-+}/2^{+-}/3^{-+}/4^{+-}$, etc. We investigate for the first time the exotic quantum…
The recently observed pentaquark baryons $\Theta^{+}$ and $\Xi^{--}$ are studied in the dual gravity theory of QCD. By developing a general formulation useful for studying the branched string web in a curved space, simple mass formulae of…
A quark model, which reproduces the ground-state mesons and baryons, i.e., the threshold energies, is applied to the $qqqc\bar c$ configurations, where $q$ is a light quark and~$c$ the charmed quark. In the calculation, several open…
Results for the equation of state in 2+1 flavor QCD at zero net baryon density using the Highly Improved Staggered Quark (HISQ) action by the HotQCD collaboration are presented. The strange quark mass was tuned to its physical value and the…
We consider the ${\bar D}^{(*)}\Sigma_c^{(*)}$ states, together with $J/\psi N$ and other coupled channels, and take an interaction consistent with heavy quark spin symmetry, with the dynamical input obtained from an extension of the local…
In this work, we adopt the diquark model, construct the diquark-diquark-antiquark type currents with the light quarks $uus$ in two octets, and study the $uusc\bar{c}$ pentaquark states in the framework of the QCD sum rules systematically.…
The classical quenched quark models with three constituent quarks provide a good description for the baryon spatial ground states, but fail to reproduce the spectrum of baryon excited states. More and more evidences suggest that unquenched…
Very recently, the LHCb Collaboration observed distinct structures with the $cc\bar{c}\bar{c}$ in the $J/\Psi$-pair mass spectrum. In this work, we construct four scalar ($J^{PC} = 0^{++}$) $[8_c]_{Q\bar{Q^\prime}}\otimes [8_c]_{Q^\prime…
In the framework of the color-magnetic interaction model, we have systematically calculated the mass splittings for the S-wave triply heavy pentaquark states with the configuration $qqQQ\bar{Q}$ $(Q=c,b;q=u,d,s)$. Their masses are estimated…
In the framework of the quark delocalization color screening model (QDCSM), we systematically investigate the double-charm and double-strange tetraquark systems $cc\bar{s}\bar{s}$ with two structures: meson-meson and diquark-antidiquark.…
The existence of an anti-decuplet of pentaquark particles has been predicted some year ago within the chiral soliton model. In the last year, several experimental groups have reported evidence for a S=+1 baryon resonance, with mass ranging…