Search for the Pentaquark Θ+ via the π−p → K−X Reaction at J-PARC (eBook)

Manabu Moritsu (Autor)

eBook Download: PDF

2016 | 1st ed. 2016
XIII, 123 Seiten
Springer Singapore (Verlag)
978-981-10-0012-6 (ISBN)

Infos

This theses reports on an experimental search for an exotic hadron, Θ⁺(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 Θ⁺ was strongly constrained. 

The Θ⁺ pentaquark was searched for via the π^- 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 Θ⁺. 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 π^- 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/c². 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 Θ⁺ was evaluated. The upper limits on the decay width were estimated to be 0.36 and 1.9 MeV for the Θ⁺ spin-parity of 1/2⁺ and 1/2^-, respectively. These are quite small for a width of ordinary hadron resonances, and the existence of Θ⁺ was strongly constrained and is doubtful.

---

This theses reports on an experimental search for an exotic hadron, I +(1540) pentaquark, which is a genuine exotic hadron with a five-quark system of uuddsbar. The results of this book support that the existence of I + was strongly constrained. The I + pentaquark was searched for via the I - p nbsp;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 I +. 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 I - p nbsp;K- X reaction, and the upper limit of the production cross section was found to be less than 0.28 I b/sr at the 90% confidence level in a mass region of 1500-1560 MeV/c2. 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 I + was evaluated. The upper limits on the decay width were estimated to be 0.36 and 1.9 MeV for the I + spin-parity of 1/2+ and 1/2-, respectively. These are quite small for a width of ordinary hadron resonances, and the existence of I + was strongly constrained and is doubtful.

Inhalt

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

Produkt-Details

• Erscheint lt. Verlag: 17.2.2016
• Reihe/Serie: Springer Theses
• Reihe/Serie: Springer Theses
• Zusatzinfo: XIII, 123 p. 86 illus., 38 illus. in color.
• Verlagsort: Singapore
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Atom- / Kern- / Molekularphysik
• Themenwelt: Technik
• Schlagworte: DIANA and Belle Collaborations • Exotic hadron search • J-PARC hadron experimental facility • J-PARC K1.8 beam line • Pentaquark search • Pion-induced reaction for strangeness production • Superconducting kaon spectrometer
• ISBN-10: 981-10-0012-3 / 9811000123
• ISBN-13: 978-981-10-0012-6 / 9789811000126