Measurement of the Branching Fraction for B->eta' K and Search for B->eta'pi+

TL;DR

This paper measures the branching fractions of specific B meson decays involving eta' mesons, reports no signal for one decay mode, and investigates CP asymmetry, providing new experimental data on these rare processes.

Contribution

It provides the first measurements of B->eta'K branching fractions and sets upper limits for B->eta'pi+ decays, along with CP asymmetry constraints.

Findings

BF(B+ -> eta'K+) = (79^{+12}_{-11} ± 9) x 10^-6

BF(B0 -> eta'K0) = (55^{+19}_{-16} ± 8) x 10^-6

No signal for B+ -> eta' pi+; upper limit set at 7 x 10^-6

Abstract

We report measurements for two-body charmless B decays with an eta' meson in the final state. Using 11.1X10^6 BBbar pairs collected with the Belle detector, we find BF(B^+ ->eta'K^+)=(79^+12_-11 +-9)x10^-6 and BF(B^0 -> eta'K^0)=(55^+19_-16 +-8)x10^-6, where the first and second errors are statistical and systematic, respectively. No signal is observed in the mode B^+ -> eta' pi^+, and we set a 90% confidence level upper limit of BF(B^+-> eta'pi^+) < 7x10^-6. The CP asymmetry in B^+- -> eta'K^+- decays is investigated and a limit at 90% confidence level of -0.20<Acp<0.32 is obtained.