February 14, 1994 Journal article Open Access

Observation of an excited state of the Lambda c+ baryon.

T. F. Lin; P. Lebrun; James E Wiss; G. N. Kim; P. H. Kasper; John Perry Cumalat; F. Davenport; Cristina Riccardi; M. S. Nehring; V. Arena; D. Torretta; Sandra Malvezzi; C. Dallapiccola; Paolo Vitulo; S. Sala; M. Vittone; S. Sarwar; P. M. Yager; M. Di Corato; A. E. Kreymer; L. Cinquini; G. Alimonti; D. J. Harding; B. O'Reilly; G. P. Grim; Robert Gardner; J. A. Swiatek; P. L. Frabetti; Fabrizio Fabbri; Gabriele Gianini; D. Buchholz; E. Meroni; S. Cihangir; V. S. Paolone; James R. Wilson; W. D. Shephard; Stefano Bianco; J. F. Ginkel; J. S. Kang; T. Handler; S. Shukla; R. Greene; Luigi Moroni; Stephen A. Gourlay; Senta Greene; A. Zallo; L. Perasso; G. Bellini; D. Claes; J. M. Bishop; L. Garren; J. N. Butler; Z. Y. Wu; H. W.K. Cheung; Daniele Pedrini; B. Caccianiga; Willard Johns; J. F. Filasetta; C. Castoldi; F. Leveraro; A. Sala; Randy Ruchti; P. H. Garbincius; G. R. Blackett; M. Pisharody; Alan D. Lopez; Marco Giammarchi; P. Inzani; N. M. Cason; S. P. Ratti; Paul Sheldon; R. Culbertson; B. G. Cheon; K. Y. Kim; C. J. Kennedy; G. Boca; I. Gaines; D. L. Puseljic; Dario Menasce; B. Gobbi

An observation of an excited ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$ baryon decaying to ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$, with ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$\ensuremath{\rightarrow}${\mathit{pK}}^{\mathrm{\ensuremath{-}}}$${\mathrm{\ensuremath{\pi}}}^{+}$, is presented. We reconstruct 39.7\ifmmode\pm\else\textpm\fi{}8.7${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$ baryons with a mass of 340.4\ifmmode\pm\else\textpm\fi{}0.6\ifmmode\pm\else\textpm\fi{}0.3 MeV/${\mathit{c}}^{2}$ above the ${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$ mass. The upper limit on the resonant branching ratio is B(${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Sigma}}}_{\mathit{c}}$${\mathrm{\ensuremath{\pi}}}^{\ifmmode\pm\else\textpm\fi{}}$)/B(${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+\mathrm{*}}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\Lambda}}}_{\mathit{c}}^{+}$ ${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{\mathrm{\ensuremath{-}}}$)36% at the 90% confidence level.