Related papers: Some Comments on the Putative $\Theta^ +$ (1543) E…

In the year 2008 COMPASS recorded diffractive events of the signature \pi^-(191 GeV) p --> X_fast p. We present results of the analysis of the subsystems X = \eta(')\pi^-. Besides the known resonances a_2(1320), a_4(2040), we study the…

Recent strong experimental evidence of a narrow exotic S = +1 baryon resonance, $\Theta^+$, suggests the existence of other exotic baryons. We discuss the prospects of confirming earlier experimental evidence of $\Theta^+$ and the…

An event-based partial wave analysis (PWA) of the reaction gamma p -> p omega has been performed on a high-statistics dataset obtained using the CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This analysis…

For the first time, the reaction gamma d -> Lambda n K+ has been analyzed in order to search for the exotic pentaquark baryon Theta+(1540). The data were taken at Jefferson Lab, using the Hall-B tagged-photon beam of energy between 0.8 and…

We theoretically investigate a possibility of an $\eta ^{\prime} d$ bound state and its formation in the $\gamma d \to \eta d$ reaction. First, in the fixed center approximation to the Faddeev equations we obtain an $\eta ^{\prime} d$ bound…

The reaction pp->p K0 pi+ Lambda has been studied with the ANKE spectrometer at COSY-Juelich at a beam momentum of 3.65 GeV/c in order to search for a possible signal of the pentaquark Theta+(1540), decaying into the p K0 system. By…

The hint for a possible resonance in the diphoton channel with mass of 750~GeV disappeared in the data presented at ICHEP'16 by ATLAS and CMS. However, the diphoton final state remains as one of the golden channels for new physics…

We suggest to classify baryon resonances as single-quark states in a mean field, and/or as its collective excitations. Identifying the Roper resonance N(1440), the nucleon resonance N(1535), and the singlet hyperon Lambda(1405) as…

We investigate the $\eta \bar{K}K^*$ three body system in order to look for possible $I^G(J^{PC})=0^+(1^{-+})$ exotic states in the framework of the fixed center approximation to the Faddeev equation. We assume the scattering of $\eta$ on a…

Motivated by the recent discovery of the exotic S=+1 narrow baryon resonance Theta^+ at 1540 MeV, with quark content {uudd sbar}, we conjecture the existence of its anti-charmed analogue Theta_c, with quark content {uudd cbar}, and compute…

The data collected by ATIC, PPB-BETS, FERMI-LAT and HESS all indicate that there is an electron/positron excess in the cosmic ray energy spectrum above $\sim$ 100 GeV, although different instrumental teams do not agree on the detailed…

We consider the effect of an exotic S=+1 $\Theta^+$ resonance on the scattering of neutral kaons off protons. Explicit results are presented for the $K^0_L p$ total cross sections.

Anomalous transitions involving photons derived by many-body interaction of the form, $\partial_{\mu} G^{\mu}$, in the standard model are studied. This does not affect the equation of motion in the bulk, but makes wave functions modified,…

We consider the properties of the diffusion controlled reaction A+B->0 in the steady state, where fixed currents of A and B particles are maintained at opposite edges of the system. Using renormalisation group methods, we explicitly…

A high-resolution (sigma_instr. = 1.5 MeV) search for narrow states (Gamma < 10 MeV) with masses of M_x approx 1500-1850 MeV in ep -> e'K^+ X, e'K^- X and e' pi^+ X electroproduction at small angles and low Q^2 was performed. These states…

We report on four $\Sigma$'s and three $\Lambda$'s, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave $(1/2)^+$ resonances found by solving the Faddeev equations in the coupled channel approach, which can be associated to the…

Additional broader I=0 states in the KN channel near $\Theta^+$(1540) are expected in many models, making the absence of any signature in the K$^+$-deuteron scattering data even more puzzling. In an ideal "three-body" picture the $\Theta$…

Coupled-channel $\pi K$ and $\eta K$ scattering amplitudes are determined by studying the finite-volume energy spectra obtained from dynamical lattice QCD calculations. Using a large basis of interpolating operators, including both those…

CLAS photoproduction data on deuterium and hydrogen targets have been analyzed in a search for an exotic baryon state with strangeness S=+1, the \Theta^+ (originally named the Z^+). This resonance was predicted recently in theoretical work…

In terms of the heavy chiral Lagrangian and the unitarized coupled-channel scattering amplitude, interaction between the heavy meson and the light pseudoscalar meson is studied. By looking for the pole of scattering matrix on an appropriate…