We searched for the Φ−−(1860) pentaquark in the photoproduction process off the deuteron in the Ξ−π−-decay channel using CLAS. The invariant-mass spectrum of the Ξ−π− system does not indicate any statistically significant enhancement near the reported mass M=1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90%-confidence-level upper limit of 0.7 nb for the photoproduction cross section of Φ−−(1860) with a consecutive decay into Ξ−π− in the photon-energy range 4.5GeV
Physical Review C
Egiyan, H.; Biselli, Angela; and CLAS Collaboration, "Upper limits for the photoproduction cross section for the Φ−− (1860) pentaquark state off the deuteron" (2012). Physics Faculty Publications. 21.
H. Egiyan et al. [CLAS Collaboration], "Upper limits for the photoproduction cross section for the Φ−− (1860) pentaquark state off the deuteron," Physical Review C, Volume 85, Issue 1 015205 (2012). DOI: 10.1103/PhysRevC.85.015205