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Search for CP violation in hyperon decays.

  • Author(s): Zyla, Piotr
  • Chan, A.
  • Chen, Y.C.
  • Ho, C.
  • Teng, P.K.
  • Choong, W.S.
  • Gidal, G.
  • Fu, Y.
  • Gu, P.
  • Jones, T.D.
  • Luk, K.B.
  • Turko, B.
  • James, C.
  • Volk, J.
  • Felix, J.
  • Burnstein, R.A.
  • Chakrovorty, A.
  • Kaplan, D.M.
  • Lederman, L.M.
  • Luebke, W.
  • Rajaram, D.
  • Rubin, H.A.
  • Solomey, N.
  • Torun, Y.
  • White, C.G.
  • White, S.L.
  • Leros, N.
  • Perroud, J.P.
  • Gustafson, H.R.
  • Longo, M.J.
  • Lopez, F.
  • Park, H.K.
  • Clark, K.
  • Jenkins, M.
  • Dukes, E.C.
  • Durandet, C.
  • Holmstrom, T.
  • Huang, M.
  • Lu, L.
  • Nelson, K.S.
  • et al.
Abstract

Direct CP violation in nonleptonic hyperon decays can be established by comparing the decays of hyperons and anti-hyperons. For Xi decay to Lambda pi followed by Lambda to p pi, the proton distribution in the rest frame of Lambda is governed by the product of the decay parameters alXi alLam. The asymmetry A_Xi Lambda, proportional to the difference of alXi alLam of the hyperon and anti-hyperon decays, vanishes if CP is conserved. We report on an analysis of a fraction of 1997 and 1999 data collected by the Hyper CP (E871) collaboration during the fixed-target runs at Fermilab. The preliminary measurement of the asymmetry is AXiLam = [ -7 pm 12(rm stat) pm 6.2(rm sys) ] times 10-4, an order of magnitude better than the present limit.

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