Related papers: A Naturally Narrow Positive Parity Theta^+
Recently the so-called $\Theta^+$ resonance has been reported first from SPring8\cite{nakano} and many following experiments showed apparent confirmation of the state. Since $\Theta^+$ exclusively decays into either $K^+ n$ or $K^0 p$, it…
Assuming the two diquark structure for the pentaquark state as advocated in the Jaffe-Wilczek model, we study the strong decays of light and heavy parity-even pentaquark states using the light-front quark model in conjunction with the…
We report on a study of the pentaquark Theta^+(1540), using a variety of different interpolating fields. We use Chirally Improved fermions in combination with Jacobi smeared quark sources to improve the signal and get reliable results even…
We investigate the effect of chiral phase transition on the pentaquark $\Theta^+$ mass and width at one-loop level of $N\Theta^+K$ coupling at finite temperature and density. The behavior of the mass, especially the width in hadronic medium…
Recently several proposals were put forward to determine the parity of narrow baryonic resonances, in particular the $\Theta^+$. In these proceedings we will briefly comment on the general problems in this task and then discuss in detail…
A systematic lowering in mass of strangeness ambiguous $pK^0_S$ peaks relative to the $nK^+$ is noted. We discuss how measurement of $\gamma p\to \Theta^+ K^0_S\to p K^0_S K^0_S \to p\pi^+\pi^-\pi^+\pi^-$ in association with $\gamma p\to…
The existence of the $\Theta^+$ pentaquark requires a peculiar mechanism to explain its stability. Looking at quark clusters, notably diquark and triquark configurations, such a mechanism may be found in the color-magnetic interaction…
There is a multiplicity of charge ordered, pairing-based or pair density wave theories of the cuprate pseudogap, albeit arising from different microscopic mechanisms. For mean field schemes (of which there are many) we demonstrate here that…
The hidden-charmed pentaquark $P_c(4450)$ and the charmonium-like state $Y(4274)$ are investigated as a $\bar{D}^*\Sigma_c$ and a $D_s\bar{D}_{s0}(2317)$ molecular state, respectively. The spin parities of these two states cannot be well…
The mass and decay width of the $\Theta^+(1540)$ with isospin 0 are investigated in a constituent quark model comprising $uudd\bar{s}$ quarks. The resonance state for the $\Theta^+$ is identified as a stable solution in correlated basis…
P-wave pentaquarks with strangeness +1, I=0 and J^P=1/2^+ are studied in the non-relativistic quark model with instanton induced interaction (III). We present their mass splittings and orbital-spin-isospin-color structures. It is found that…
Dynamical calculations are performed for all members of the flavor antidecuplet to which the pentaquark $\Theta^+$ belongs. The framework is a constituent quark model where the short-range interaction has a flavor-spin structure. From…
As our recent quark model calculation~\cite{Noh:2023fdy} suggests a strong possibility of a compact $T_{cc}$ that closely reproduces experimental mass, we have a strong incentive to extend our work to investigate the possible compact…
The QCD sum rule method is formulated for the strangeness +1 pentaquark baryon with isospin I=0 and spin-parity J^P = 3/2^\pm. The spin-3/2 states are considered to be narrower than the spin-1/2 ones, and thus may provide a natural…
The experimental evidence for pentaquarks, both old an new, is discussed. Constraints due to $K^+N$ scattering data from previous decades is first reviewed, followed by experiments with positive evidence and those with null results.…
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 study compact hidden charm pentaquarks in the Born-Oppenheimer approximation, previously introduced for tetraquarks, assuming the heavy pair to be in a color octet. We show that Fermi statistics applied to the complex of the three light…
We study $IJ^P=0{3/2}^\pm$ and $1{3/2}^\pm$ pentaquark states with $S=+1$ in the QCD sum rule approach. The QCD sum rule for positive parity states and that for negative parity are independently derived. The sum rule suggests that there…
Several recent experiments have reported evidence for a narrow baryon resonance with positive strangeness ($\Theta^+$) at a mass of 1.54 GeV/$c^2$. Baryons with $S=+1$ cannot be conventional $qqq$ states and the reports have thus generated…
Motivated by the possible observation of the $\Theta^+(1530)$, we study the quark structure of pentaquark states in quenched lattice QCD. The complete set of 19 local sources that have the proper symmetry for positive or negative parity…