Indication of a deeply bound compact K-pp state formed in the pp -> p Lambda K+ reaction at 2.85 GeV
nucl-ex
/ Authors
T. Yamazaki, M. Maggiora, P. Kienle, K. Suzuki, A. Amoroso, M. Alexeev, F. Balestra, Y. Bedfer, R. Bertini, L. C. Bland
and 27 more authors
A. Brenschede, F. Brochard, M. P. Bussa, Seonho Choi, M. L. Colantoni, R. Dressler, M. Dzemidzic, J. -Cl. Faivre, L. Ferrero, J. Foryciarz, I. Froehlich, V. Frolov, R. Garfagnini, A. Grasso, S. Heinz, W. W. Jacobs, W. Kuhn, A. Maggiora, D. Panzieri, H. -W. Pfaff, G. Pontecorvo, A. Popov, J. Ritman, P. Salabura
/ Abstract
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.