Related papers: Experimental Outlook for the Pentaquark
We present results for the selfenergy of the $\Theta^+$ pentaquark in nuclei associated with two sources: the $KN$ decay of the $\Theta^+$ and the two meson baryon decay channels of the $\Theta^+$ partners in an antidecuplet of baryons. The…
The masses of pentaquarks $uudd\bar s$ are calculated within the framework of a semirelativistic effective QCD Hamiltonian, using a diquark picture. This approximation allows a correct treatment of the confinement, assumed here to be…
We estimate the mass of the pentaquark state with QCD sum rules and find that pentaquark states with isospin $I=0, 1, 2$ lie close to each other around $(1.55\pm 0.15)$ GeV. The experimentally observed baryon resonance $\Theta^+ (1540)$…
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 analyse the decay $\Theta_s(1/2^+)\to NK$ in a non-relativistic Fock space description using three and five constituent quarks for the nucleon and the pentaquark, respectively. Following Jaffe and Wilczek \cite{jw}, we assume that…
We search for the strange pentaquark $\Theta^+$ using kaon interactions in the material of the Belle detector. No signal is observed in the $p K_S$ final state, while in the $p K^-$ final state we observe $\sim 1.6 \cdot 10^4$…
The newly discovered exotic $\Theta$ baryon of mass 1540 MeV (and very small width) truly has a very low mass, if it is a pentaquark system of even parity. A schematic model in which the coherent interaction of $u\bar s$ and $d\bar s$ pairs…
In a diquark-diquark-antiquark picture of the pentaquark we study the decay $\Theta \to K^{+} n$ within the framework of QCD sum rules. After evaluation of the relevant three-point function, we extract the coupling $g_{\Theta nK}$ which is…
Recent evidence for pentaquark baryons is critically reviewed in the light of new high statistics data. The search of the WA89 experiment for the $\Xi^{--}(1860)$ is presented in detail and consequences of its non-observations are…
We study the very recently discovered Theta+ (1540) at SPring-8, at ITEP and at CLAS-Thomas Jefferson Lab. We apply the same RGM techniques that already explained with success the repulsive hard core of nucleon-nucleon, kaon-nucleon exotic…
We present an analysis of the newly observed pentaquark $P_c(4312)^+$ to shed light on its quantum numbers. To do that, the QCD sum rule approach is used. The measured mass of this particle is close to $\Sigma_c^{++}\bar{D}^-$ threshold and…
Recently several experiments have reported evidences for pentaquark $\Theta^+$. H1 experiment at HERA-B has also reported evidence for $\Theta_c$. $\Theta^+$ is interpreted as a bound state of an $\bar s$ with other four light quarks $udud$…
We calculate the width of the Theta(1540) pentaquark in a relativistic model in which the pentaquark is considered to be composed of a scalar diquark and a spin 1/2 triquark. We consider both positive and negative parity for the pentaquark.…
The properties of three new particles X(3872), Y(3940) and Z(3931), recently dicovered by the Belle collaboration, are briefly reviewed. Negative results of the search for the pentaquark $\Theta(1540)^+$ are also presented
By using a language as accessible to a broad audience as possible, in this note we present evidence suggesting scientific caution prior to final claims that neutrinos and quarks are actual physical particles existing in our spacetime. We…
We investigate three possible pentaquark candidates, one of which contains a single charm quark and the other two contain triple charm quarks in their substructure. To this end we apply QCD sum rule method and take into account both the…
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…
We consider a $[ud]^2\bar{s}$ current, in the finite-density QCD sum rule approach, to investigate the scalar and vector self-energies of the recently observed pentaquark state $\Theta^+(1540)$, propagating in nuclear mater. We find that,…
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…