Indication of a Deeply Bound and CompactK−ppState Formed in thepp→pΛK+Reaction at 2.85 GeV

T. Yamazaki, M. Maggiora, P. Kienle, K. Suzuki, A. Amoroso, M. Alexeev, F. Balestra, Y. Bedfer, R. Bertini, L. C. Bland, A. Brenschede, F. Brochard (+25 others)
2010 Physical Review Letters  
We have analyzed data of the DISTO experiment on the exclusive pp -> p Lambda K+ reaction at 2.85 GeV to search for a strongly bound compact K-pp (= X) state to be formed in the pp -> K+ + X reaction. The observed spectra of the K+ missing-mass and the p Lambda invariant-mass with high transverse momenta of p and K+ revealed a broad distinct peak with a mass M_X = 2265 +- 2 (stat) +- 5 (syst) MeV/c2 and a width Gamma_X = 118 +- 8 (stat) +- 10 (syst) MeV.
doi:10.1103/physrevlett.104.132502 pmid:20481879 fatcat:5lb6sb5ccjbbrekn4koxhugrzy