Study of the Bc+ → J/ψDs+ and Bc+ → J/ψDs∗+ decays with the ATLAS detector

Allbrooke, B M M, Asquith, L, Cerri, A, Chavez Barajas, C A, De Santo, A, Salvatore, F, Santoyo Castillo, I, Suruliz, K, Sutton, M R, Vivarelli, I and The ATLAS Collaboration, (2016) Study of the Bc+ → J/ψDs+ and Bc+ → J/ψDs∗+ decays with the ATLAS detector. European Physical Journal C: Particles and Fields, 76 (1). a4. ISSN 1434-6044

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Abstract

The decays Bc+→J/ψDs+ and Bc+→J/ψDs∗+ are studied with the ATLAS detector at the LHC using a dataset corresponding to integrated luminosities of 4.9 and 20.6 fb −¹ of pp collisions collected at centre-of-mass energies √s=7 TeV and 8 TeV, respectively. Signal candidates are identified through J/ψ→μ+μ− and Ds(∗)+→ϕπ+(γ/π0)decays. With a two-dimensional likelihood fit involving the Bc+ econstructed invariant mass and an angle between the + and Ds+ candidate momenta in the muon pair rest frame, the yields of Bc+→J/ψDs+ and Bc+→J/ψDs∗+, and the transverse polarisation fraction in Bc+→J/ψDs∗+ decay are measured. The transverse polarisation fraction is determined to be Γ±±(Bc+→J/ψDs∗+)/Γ(Bc+→J/ψDs∗+)=0.38±0.23±0.07, and the derived ratio of the branching fractions of the two modes is BBc+→J/ψDs∗+/BBc+→J/ψDs+=2.8−0.8+1.2±0.3, where the first error is statistical and the second is systematic. Finally, a sample of Bc+→J ψπ+ decays is used to derive the ratios of branching fractions BBc+→J/ψDs+/BBc+→J/ψπ+=3.8±1.1±0.4±0.2 and BBc+→J/ψDs∗+/BBc+→J ψπ+=10.4±3.1±1.5±0.6, where the third error corresponds to the uncertainty of the branching fraction of Ds+→ϕ(K+K−)π+ decay. The available theoretical predictions are generally consistent with the measurement.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Experimental Particle Physics Research Group
Subjects: Q Science > QC Physics
Depositing User: Billy Wichaidit
Date Deposited: 11 Apr 2017 10:37
Last Modified: 11 Apr 2017 10:41
URI: http://sro.sussex.ac.uk/id/eprint/67362

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Project NameSussex Project NumberFunderFunder Ref
ATLASG0275STFC-SCIENCE AND TECHNOLOGY FACILITIES COUNCILST/I006048/1