Abstract
Using of data recorded by the BABAR detector at the PEP-II electron-positron collider, signal events for the decay channel are analyzed. This decay mode is dominated by the contribution. We determine the parameters: , , and the Blatt-Weisskopf parameter , where the first uncertainty comes from statistics and the second from systematic uncertainties. We also measure the parameters defining the corresponding hadronic form factors at (, ) and the value of the axial-vector pole mass parametrizing the variation of and : . The -wave fraction is equal to . Other signal components correspond to fractions below 1%. Using the channel as a normalization, we measure the semileptonic branching fraction: , where the third uncertainty comes from external inputs. We then obtain the value of the hadronic form factor at : . Fixing the -wave parameters, we measure the phase of the wave for several values of the mass. These results confirm those obtained with production at small momentum transfer in fixed target experiments.
15 More- Received 13 December 2010
DOI:https://doi.org/10.1103/PhysRevD.83.072001
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