Search for exotic baryons in double radiative capture on pionic hydrogen

Abstract: We report a search for low-lying exotic baryons via double radiative capture on pionic hydrogen. The data were collected at the TRIUMF cyclotron using the RMC spectrometer by detecting gamma-ray pairs from pion stops in liquid hydrogen. We found no evidence to support an earlier claim for exotic baryons of masses 1004 and , and set upper limits on exotic baryon mediated capture of and , respectively. We also obtained bounds on the couplings between exotic baryons and ordinary nucleons. [Copyright &y& Elsevier]