Archivio Istituzionale della RicercaThe pentaquark Theta(+) has been searched for via the pi(-) p --> K- X reaction with beam momenta of 1.92 and 2.01 GeV/c at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The upper limits on the production cross section averaged over the scattering angle from 2 degrees to 15 degrees in the laboratory frame were found to be less than 0.28 mu b/sr at the 90% confidence level for both the 1.92- and 2.01- GeV/c data. The systematic uncertainty of the upper limits was controlled within 10%. Constraints on the Theta(+) decay width were also evaluated with a theoretical calculation using an effective Lagrangian. The present result implies that the width should be less than 0.36 and 1.9 MeV for the spin-parity of 1/2(+) and 1/2(-), respectively.
High-resolution search for the Theta(+) pentaquark via a pion-induced reaction at J-PARC / Moritsu, M.; Adachi, S.; Agnello, Michelangelo; Ajimura, S.; Aoki, K.; Bhang, H. C.; Bassalleck, B.; Botta, E.; Bufalino, Stefania; Chiga, N.; Ekawa, H.; Evtoukhovitch, P.; Feliciello, A.; Fujioka, H.; Hayakawa, S.. - In: PHYSICAL REVIEW. C, NUCLEAR PHYSICS. - ISSN 0556-2813. - STAMPA. - 90:3(2014), pp. 1-11. [10.1103/PhysRevC.90.035205]
High-resolution search for the Theta(+) pentaquark via a pion-induced reaction at J-PARC
AGNELLO, MICHELANGELO;BUFALINO, STEFANIA;
2014
Abstract
The pentaquark Theta(+) has been searched for via the pi(-) p --> K- X reaction with beam momenta of 1.92 and 2.01 GeV/c at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The upper limits on the production cross section averaged over the scattering angle from 2 degrees to 15 degrees in the laboratory frame were found to be less than 0.28 mu b/sr at the 90% confidence level for both the 1.92- and 2.01- GeV/c data. The systematic uncertainty of the upper limits was controlled within 10%. Constraints on the Theta(+) decay width were also evaluated with a theoretical calculation using an effective Lagrangian. The present result implies that the width should be less than 0.36 and 1.9 MeV for the spin-parity of 1/2(+) and 1/2(-), respectively.
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https://hdl.handle.net/11583/2588242
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