A research has been made to look for a signature of the positive-strangeness baryon resonance Theta(+) (1530), which is expected to decay into pK(0). A peak is bbserved in the p pi+pi(-) invariant mass distribution in antiproton-He-4 annihilation reactions at rest with production of two pi+pi(-) pairs with invariant mass close to the KO mass. The annihilation reactions on 4 He can involve two to four nucleons producing an energy blob characterized by high strangeness content. The peak is centred around 1560.0 +/- 3.7 MeV and its width is very narrow. The statistical significance is 2.7; this value is considered of not sufficient significance to claim support of the Theta(+). The data were collected with the Obelix spectrometer at the LEAR machine of CERN.

Search for the Theta+(1530) pentaquark in antiproton He-4 annihilation at rest

L. LAVEZZI;BOTTA, Elena;BRESSANI, Tullio;COSTA, Sergio;MARCELLO, Simonetta;BALESTRA, Ferruccio;BUSSA, Maria Pia;BUSSO, Luigi;FERRERO, Livio;GARFAGNINI, Raffaello;GRASSO, Antonino;PANZIERI, Daniele;
2006-01-01

Abstract

A research has been made to look for a signature of the positive-strangeness baryon resonance Theta(+) (1530), which is expected to decay into pK(0). A peak is bbserved in the p pi+pi(-) invariant mass distribution in antiproton-He-4 annihilation reactions at rest with production of two pi+pi(-) pairs with invariant mass close to the KO mass. The annihilation reactions on 4 He can involve two to four nucleons producing an energy blob characterized by high strangeness content. The peak is centred around 1560.0 +/- 3.7 MeV and its width is very narrow. The statistical significance is 2.7; this value is considered of not sufficient significance to claim support of the Theta(+). The data were collected with the Obelix spectrometer at the LEAR machine of CERN.
2006
779
116
141
NEUTRINO INTERACTIONS; POSITIVE-STRANGENESS; BARYON RESONANCE; NARROW; COLLISIONS; K(S)(0)P; PHOTOPRODUCTION; DETECTOR; NUCLEI; STATE
Panzarasa, A.; Bendiscioli, G.; Fontana, A.; Lavezzi, L.; Montagna, P.; Rotondi, A.; Salvini, P.; LODI RIZZINI, E.; Corradini, M.; Venturelli, L.; Zenoni, A.; Donzella, A.; Botta, Elena; Bressani, Tullio; Costa, Sergio; Calvo, D.; Feliciello, A.; Filippi, A.; Marcello, Simonetta; Agnello, M.; Iazzi, F.; Minetti, B.; Balestra, Ferruccio; Bussa, Maria Pia; Busso, Luigi; Cerello, P.; Denisov, O.; Ferrero, Livio; Garfagnini, Raffaello; Grasso, Antonino; Maggiora, A.; Tosello, F.; Panzieri, Daniele; Gorchakov, O. E.; Prakhov, S. N.; Rozhdestvensky, A. M.; Sapozhnikov, M. G.; Tretyk, V. I.; Cicalo, C.; DE FALCO, A.; Masoni, A.; Puddu, G.; Serci, S.; Usai, G.; CURCEANU PETRASCU, C.; Gianotti, P.; Guaraldo, C.; Lanaro, A.; Lucherini, V.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/36557
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