Author/Authors :
Crystal Barrel Collaboration، نويسنده , , A. Abele، نويسنده , , J. Adomeit، نويسنده , , C. Amsler، نويسنده , , C.A. Baker، نويسنده , , B.M. Barnett، نويسنده , , C.J. Batty، نويسنده , , M. Benayoun، نويسنده , , A. Berdoz، نويسنده , , S. Bischoff، نويسنده , , P. Blüm، نويسنده , , K. Braune، نويسنده , , D.V. Bugg، نويسنده , , Steven T. Case، نويسنده , , O. Cramer، نويسنده , , K.M. Crowe، نويسنده , , T. Degener، نويسنده , , N. Djaoshvili، نويسنده , , M. Doser، نويسنده , , W. Dünnweber، نويسنده , , et al.، نويسنده ,
Abstract :
We report the first observation of antiproton annihilation on the deuteron into two-body channels with open strangeness. These reactions are of the Pontecorvo type, designating annihilations kinematically not possible on a free nucleon. With antiprotons stopped in a liquid deuterium target, a K0S and Λenriched sample of events, corresponding to about 109 annihilations, was recorded with the Crystal Barrel experiment, using a Silicon microstrip detector for triggering on secondary decays. The final states ΛK0S and Σ0K0S, with Σ0→Λγ, Λ→pπ−, K0S→π+π−, and the equivalent final states ΛK0L and Σ0K0L, with noninteracting K0L, were identified. The pd branching fraction into ΛK0 and Σ0K0 are (2.35±0.45)×10−6 and (2.15±0.45)×10−6, respectively. This similarity disagrees strongly with two-step model predictions and supports the statistical (fireball) model.
