Abstract: | A search for charmless three-body decays of B0 and B0s mesons with a KS0
meson in the final state is performed using the pp collision data,
corresponding to an integrated luminosity of 1.0 /fb, collected at a
centre-of-mass energy of 7 TeV recorded by the LHCb experiment. Branching
fractions of the B0(s) -> KS0 h+ h’- decay modes (h(’) = pi, K), relative to
the well measured B0 -> KS0 pi+ pi- decay, are obtained. First observation of
the decay modes B0s -> KS0 K+/- pi-/+ and B0s -> KS0 pi+ pi- and
confirmation of the decay B0 -> KS0 K+/- pi-/+ are reported. The following
relative branching fraction measurements or limits are obtained
BF(B0 -> KS0 K+/- pi-/+) / BF(B0 -> KS0 pi+ pi-) = 0.128 +/- 0.017 (stat.)
+/- 0.009 (syst.),
BF(B0 -> KS0 K+ K-) / BF(B0 -> KS0 pi+ pi-) = 0.385 +/- 0.031 (stat.) +/-
0.023 (syst.),
BF(B0s -> KS0 pi+ pi-) / BF(B0 -> KS0 pi+ pi-) = 0.29 pm 0.06 (stat.)
+/- 0.03 (syst.) +/- 0.02 (f_s/f_d),
BF(B0s -> KS0 K+/- pi-/+) / BF(B0 -> KS0 pi+ pi-) = 1.48 +/- 0.12 (stat.)
+/- 0.08 (syst.) +/- 0.12 (f_s/f_d),
BF(B0s -> KS0 K+ K-) / BF(B0 -> KS0 pi+ pi-) E [0.004;0.068] at 90% CL. |