Confirmation of the doubly charmed baryon Epsilon(+)(cc)(3520) via its decay to pD(+)K(-)


Ocherashvili A., Moinester M., Russ J., Engelfried J., Torres I., Akgun U., ...More

PHYSICS LETTERS B, vol.628, pp.18-24, 2005 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 628
  • Publication Date: 2005
  • Doi Number: 10.1016/j.physletb.2005.09.043
  • Title of Journal : PHYSICS LETTERS B
  • Page Numbers: pp.18-24

Abstract

We observe a signal for the doubly charmed baryon Xi(cc)(+) in the decay mode Xi(cc)(+) -> pD(+)K(-) to complement the previous cc reported decay Xi(cc)(+) -> Lambda(c)(+)K(-)pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38 +/- 0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8 sigma. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4 x 10(-4). The observed mass of this state is 3518 +/- 3 MeV/c(2), consistent with the published result. Averaging the two results gives a mass of 3518.7 +/- 1.7 MeV/c(2). The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36 +/- 0.21. (c) 2005 Elsevier B.V. All rights reserved.