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Hafner, A.

Publications and source records attributed to Hafner, A..

At least 91 records · Page 5
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DOE OSTI2016

Measurement of the I = 1 / 2 K π S -wave amplitude from Dalitz plot analyses of η c → K K ¯ π in two-photon interactions

Here we study the processes γγ→K$0\atop{S}$K ± π ∓ and γγ→K + K - π 0 using a data sample of 519 fb -1 recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e + e - collider at center-of-mass energies at and near the Υ(nS) (n=2, 3, 4) resonances. We observe ηc decays to both final states and perform Dalitz plot analyses using a model-independent partial wave analysis technique. This allows a model-independent measurement of the mass-dependence of the I=1/2 Kπ S-wave amplitude and phase. A comparison between the present measurement and those from previous experiments indicates similar behavior for the phase up to a mass of 1.5 GeV/c 2 . In contrast, the amplitudes show very marked differences. Lastly, the data require the presence of a new a 0 (1950) resonance with parameters m=1931±14±22 MeV/c 2 and Γ=271±22±29 MeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Study of dynamics of D 0 → K – e + ν e and D 0 → π – e + ν e decays

Here, in an analysis of a 2.92 fb –1 data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions to be B(D 0 → K – e + ν e ) = (3.505 ± 0.014 ± 0.033)% and B(D 0 → π – e + ν e ) = (0.295 ± 0.004 ± 0.003)%. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element $f$ $^{K}_{+}$(0)|V cs | = 0.7172 ± 0.0025 ± 0.0035 and $f$ $^{π}_{+}$(0)|V cd | = 0.1435 ± 0.0018 ± 0.0009.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗