%0 Journal Article
%T Observation of (B)over-bar -> D-(*()) pi(+)pi(-)l(-)(nu)over-bar Decays in e(+)e(-) Collisions at the Upsilon(4S) Resonance
%A BABAR Collaboration (Lees, J. P. et al
%A Martinez-Vidal, F.
%A Oyanguren, A.
%J Physical Review Letters
%D 2016
%V 116
%N 4
%I Amer Physical Soc
%@ 0031-9007
%G English
%F BABARCollaborationLees_etal2016
%O WOS:000369337200004
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=2546), last updated on Thu, 25 Feb 2016 16:31:05 +0000
%X We report on measurements of the decays of (B) over bar mesons into the semileptonic final states (B) over bar -> D-(*())pi(+)pi(-)l(-)(nu) over bar, where D-(*()) represents a D or D* meson and l(-) is an electron or a muon. These measurements are based on 471 x 10(6) B (B) over bar pairs recorded with the BABAR detector at the SLAC asymmetric B factory PEP-II. We determine the branching fraction ratios R-pi+pi-(()*()) = B((B) over bar -> D-(*())pi(+)pi(-)l(-)(nu) over bar /B (B) over bar -> D-(*())l(-)(nu) over bar) using events in which the second B meson is fully reconstructed. We find R pi+pi- = 0.067 +/- 0.010 +/- 0.008 and R pi+pi-* = 0.019 +/- 0.005 +/- 0.004, where the first uncertainty is statistical and the second is systematic. Based on these results and assuming isospin invariance, we estimate that (B) over bar -> D-(*())pi pi l (nu) over bar decays, where pi denotes either a pi(+/-) and pi(0) meson, account for up to half the difference between the measured inclusive semileptonic branching fraction to charm hadrons and the corresponding sum of previously measured exclusive branching fractions.
%R 10.1103/PhysRevLett.116.041801
%U http://arxiv.org/abs/1507.08303
%U https://doi.org/10.1103/PhysRevLett.116.041801
%P 041801-7pp