Measurements of chi(3510), chi(3555), and neutral strange particles in interactions of 200 and 250 GeV/c protons and 190 GeV/c negative pions with a beryllium target

James Knute Simmons, Purdue University

Abstract

Production of the charmonium states $\chi$(3510) and $\chi$(3555) ($\chi\sb1$ and $\chi\sb2$) was observed in interactions of a beryllium target with 200 GeV/c and 250 GeV/c proton beams and a 190 GeV/c negative pion beam. The $\chi$s were seen through their decay into J/$\Psi$ + $\gamma$, and the J/$\Psi$s through their decay into muons, which were detected in a magnetic spectrometer. In $\pi\sp-$ interactions, we found that $\sigma(\chi\sb1$)/$\sigma(\chi\sb2$) was 1.28 $\pm$ 0.61, and in proton interactions was 0.19 $\pm$ 0.26. Because no clear $\chi\sb1$ signal was seen in proton interactions, we also calculated a 90% confidence level upper limit of 0.50 on this ratio. K$\sbsp{\rm s}{0}$s, $\Lambda$s, and $\bar\Lambda$s were detected in $\pi\sp-$ data through their decays into $\pi\sp+$ + $\pi\sp-$, p + $\pi\sp-$, and p + $\pi\sp+$, respectively. The small size of the area in which we were able to search for these decays limited our ability to detect neutral strange particles beyond the central region.

Degree

Ph.D.

Advisors

Barnes, Purdue University.

Subject Area

Particle physics

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