First observation of the decays ¯¯¯B0(s)→D+sK−π+π− and ¯¯¯B0s→Ds1(2536)+π−

Abstract

The first observation of the decays ¯¯¯ B 0 s → D + s K − π + π − and ¯¯¯ B 0 → D + s K − π + π − are reported using an integrated luminosity of 1.0 fb − 1 recorded by the LHCb experiment. The branching fractions, normalized with respect to ¯¯¯ B 0 s → D + s π − π + π − and ¯¯¯ B 0 s → D + s K − π + π − , respectively, are measured to be B ( ¯¯¯ B 0 s → D + s K − π + π − ) B ( ¯¯¯ B 0 s → D + s π − π + π − ) = ( 5.2 ± 0.5 ± 0.3 ) × 10 − 2 and B ( ¯¯¯ B 0 → D + s K − π + π − ) B ( ¯¯¯ B 0 s → D + s K − π + π − ) = 0.54 ± 0.07 ± 0.07 , where the first uncertainty is statistical and the second is systematic. The ¯¯¯ B 0 s → D + s K − π + π − decay is of particular interest as it can be used to measure the weak phase γ . First observation of the ¯¯¯ B 0 s → D s 1 ( 2536 ) + π − , D + s 1 → D + s π − π + decay is also presented, and its branching fraction relative to ¯¯¯ B 0 s → D + s π − π + π − is found to be B ( ¯¯¯ B 0 s → D s 1 ( 2536 ) + π − , D + s 1 → D + s π − π + ) B ( ¯¯¯ B 0 s → D + s π − π + π − ) = ( 4.0 ± 1.0 ± 0.4 ) × 10 − 3