Moritsu Search for the Pentaquark T+ via the p-p ? K-X Reaction at J-PARC

1. Auflage 2016
ISBN: 978-981-10-0012-6
Verlag: Springer Singapore
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 123 Seiten, eBook

Reihe: Springer Theses

This theses reports on an experimental search for an exotic hadron, T + (1540) pentaquark, which is a genuine exotic hadron with a five-quark system of uudds bar . The results of this book support that the existence of T +  was strongly constrained.  The T +  pentaquark was searched for via the p -  p ? K -  X reaction using a beam momentum of 2.01 GeV/c at the J-PARC hadron experimental facility, taking advantage of high-statistics and high-resolution compared with previous experiments, some of which claimed the evidence of T + . In order to realize a good missing-mass resolution of 2 MeV, the beam spectrometer and superconducting kaon spectrometer were constructed. No clear peak was observed in the missing mass spectrum of the p -  p ? K -  X reaction, and the upper limit of the production cross section was found to be less than 0.28 µb/sr at the 90% confidence level in a mass region of 1500–1560 MeV/c 2 . This upper limit is an order of magnitude smaller than that of the previous KEK experiment. Compared with a theoretical calculation using the effective Lagrangian approach, the decay width of T +  was evaluated. The upper limits on the decay width were estimated to be 0.36 and 1.9 MeV for the T +  spin-parity of 1/2 +  and 1/2 - , respectively. These are quite small for a width of ordinary hadron resonances, and the existence of T +  was strongly constrained and is doubtful.

Zielgruppe

Research

Autoren/Hrsg.

Moritsu, Manabu

Inhaltsverzeichnis

Introduction to Pentaquark Search.- Experimental Apparatus.- Data Analysis.- Results.- Discussion.- Conclusion.- Appendix.