Evidence for B^+ -> omega l^+ nu

TL;DR

This paper reports the first evidence for the B^+ -> omega l^+ nu decay, measuring its branching fraction using data from the Belle detector, with a significance of approximately 3 sigma.

Contribution

It provides the first experimental evidence for the B^+ -> omega l^+ nu decay, including a measured branching fraction and analysis methodology.

Findings

Evidence for B^+ -> omega l^+ nu decay with 155 +/- 47 events

Measured branching fraction of (1.3 +/- 0.4 +/- 0.2 +/- 0.3) x 10^-4

Preliminary result indicating a potential new decay channel

Abstract

We have searched for the decay B^+ -> omega l^+ nu in 78 fb^-1 of Y(4S) data (85.0 million BBbar events) accumulated with the Belle detector. The final state is fully reconstructed using the omega decay into pi^+ pi^- pi^0 and detector hermeticity to estimate the neutrino momentum. 155 +/- 47 signal events are found in the data, corresponding to a branching fraction of (1.3 +/- 0.4 +/- 0.2 +/- 0.3) x 10^-4, where the first two errors are statistical and systematic. The third error is due to the estimated form-factor uncertainty. (This result is preliminary.)