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Search for exotic baryons in double radiative capture on pionic hydrogen

P. A. Zolnierczuk·D. S. Armstrong·E. Christy·J. H. D. Clark·T. P. Gorringe·M. D. Hasinoff·M. A. Kovash·S. Tripathi·D. H. Wright
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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. No evidence was found to support an earlier claim for exotic baryons of masses 1004 and 1044 MeV/$c^2$. We obtain upper limits on the branching ratios for double radiative capture via these exotic states of $< 3 \times 10^{-6}$ and $< 4 \times 10^{-6}$ respectively.

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P. A. Zolnierczuk, D. S. Armstrong, E. Christy, J. H. D. Clark, T. P. Gorringe, M. D. Hasinoff, M. A. Kovash, S. Tripathi, D. H. Wright. 2004-03-23. Search for exotic baryons in double radiative capture on pionic hydrogen. https://doi.org/10.1016/j.physletb.2004.07.008

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