## Searches for Λ[0 over b] and Ξ[0 over b] decays to K[0 over s]pπ[superscript -] and K[0 over s]pK[superscript -] final states with first observation of the Λ[0 over b] → K[0 over s]pπ[superscript -] decay

##### Author(s)

Ilten, Philip James; Williams, Michael
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A search for previously unobserved decays of beauty baryons to the final states K[0 over s]pπ[superscript -] and K[0 over s]pK[superscript -] is reported. The analysis is based on a data sample corresponding to an integrated luminosity of 1.0 fb[superscript −1] of pp collisions. The Λ[0 over b] → [bar over K][superscript 0]pπ[superscript -] decay is observed with a significance of 8.6 σ, with branching fraction B(Λ[0 over b] → [bar over K][superscript 0]pπ[superscript -] = (1.26 ± 0.19 ± 0.09 ± 0.34 ± 0.05) × 10 [superscript -5], where the uncertainties are statistical, systematic, from the ratio of fragmentation fractions f [superscript Λ[0 over b]]/f[superscript d] and from the branching fraction of the B[superscript 0] → K[superscript 0]π[superscript +]π[superscript −] normalisation channel, respectively. A first measurement is made of the CP asymmetry, giving A[subscript CP](Λ[0 over b] → [bar over K][superscript 0]pπ[superscript -]) = 0.22 ± 0.13 (stat.) ± 0.03 (syst.). No significant signals are seen for Λ[0 over b] → K[0 over s]pK[superscript -] decays, Ξ[0 over b] decays to both the K[0 over s]pπ[superscript -] and K[0 over s]pK[superscript -] final states, and the Λ[0 over b] → D[bar over s] (→ K[0 over s]K[superscript -])p decay, and upper limits on their branching fractions are reported.

##### Date issued

2014-04##### Department

Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science##### Journal

Journal of High Energy Physics

##### Publisher

Springer-Verlag

##### Citation

Aaij, R., B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, J. Albrecht, F. Alessio, et al. “Searches for Λ[0 over b] and Ξ[0 over b] decays to K[0 over s]pπ[superscript -] and K[0 over s]pK[superscript -] final states with first observation of the Λ[0 over b] → K[0 over s]pπ[superscript -] decay.” J. High Energ. Phys. 2014, no. 4 (April 2014). © CERN, for the benefit of the LHCb Collaboration

Version: Final published version

##### ISSN

1029-8479

1126-6708