We use (121±1) million Υ(3S) and (98±1) million Υ(2S) mesons recorded by the BABAR detector at the PEP-II e+e- collider at SLAC to perform a study of radiative transitions involving the χbJ(1P,2P) states in exclusive decays with μ+μ-γγ final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the χb0(2P)→γΥ(2S) and χb0(1P)→γΥ(1S) transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an e+e- pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring Υ(3S)→γχb1,2(1P) decays. Additionally, we provide the most up-to-date derived branching fractions, matrix elements and mass splittings for χb transitions in the bottomonium system. Using a new technique, we also measure the two lowest-order spin-dependent coefficients in the nonrelativistic QCD Hamiltonian. © 2014 American Physical Society.

Bottomonium spectroscopy and radiative transitions involving the χ b J (1P,2P) states at B a B ar / Lees, J.P., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., Stugu, B., Brown, D.N., Kerth, L.T., Kolomensky, Y.u.G., Lee, M.J., Lynch, G., Koch, H., Schroeder, T., Hearty, C., Mattison, T.S., Mckenna, J.A., So, R.Y., Khan, A., Blinov, V.E., et al.. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 90:11(2014). [10.1103/PhysRevD.90.112010]

Bottomonium spectroscopy and radiative transitions involving the χ b J (1P,2P) states at B a B ar

DE NARDO, GUGLIELMO;SCIACCA, CRISOSTOMO;
2014

Abstract

We use (121±1) million Υ(3S) and (98±1) million Υ(2S) mesons recorded by the BABAR detector at the PEP-II e+e- collider at SLAC to perform a study of radiative transitions involving the χbJ(1P,2P) states in exclusive decays with μ+μ-γγ final states. We reconstruct twelve channels in four cascades using two complementary methods. In the first we identify both signal photon candidates in the electromagnetic calorimeter (EMC), employ a calorimeter timing-based technique to reduce backgrounds, and determine branching-ratio products and fine mass splittings. These results include the best observational significance yet for the χb0(2P)→γΥ(2S) and χb0(1P)→γΥ(1S) transitions. In the second method, we identify one photon candidate in the EMC and one which has converted into an e+e- pair due to interaction with detector material, and we measure absolute product branching fractions. This method is particularly useful for measuring Υ(3S)→γχb1,2(1P) decays. Additionally, we provide the most up-to-date derived branching fractions, matrix elements and mass splittings for χb transitions in the bottomonium system. Using a new technique, we also measure the two lowest-order spin-dependent coefficients in the nonrelativistic QCD Hamiltonian. © 2014 American Physical Society.
2014
Bottomonium spectroscopy and radiative transitions involving the χ b J (1P,2P) states at B a B ar / Lees, J.P., Poireau, V., Tisserand, V., Grauges, E., Palano, A., Eigen, G., Stugu, B., Brown, D.N., Kerth, L.T., Kolomensky, Y.u.G., Lee, M.J., Lynch, G., Koch, H., Schroeder, T., Hearty, C., Mattison, T.S., Mckenna, J.A., So, R.Y., Khan, A., Blinov, V.E., et al.. - In: PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY. - ISSN 1550-7998. - 90:11(2014). [10.1103/PhysRevD.90.112010]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/617104
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