The decays B+c→J/ψD+s and B+c→J/ψD∗+s 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 D(∗)+s→ϕπ+(γ/π0) decays. With a two-dimensional likelihood fit involving the B+c reconstructed invariant mass and an angle between the μ+ and D+s candidate momenta in the muon pair rest frame, the yields of B+c→J/ψD+s and B+c→J/ψD∗+s, and the transverse polarisation fraction in B+c→J/ψD∗+s decay are measured. The transverse polarisation fraction is determined to be Γ±±(B+c→J/ψD∗+s)/Γ(B+c→J/ψD∗+s)=0.38±0.23±0.07, and the derived ratio of the branching fractions of the two modes is B+c→J/ψD∗+s/B+c→J/ψD+s=2.8+1.2−0.8±0.3, where the first error is statistical and the second is systematic. Finally, a sample of B+c→J/ψπ+ decays is used to derive the ratios of branching fractions B+c→J/ψD+s/B+c→J/ψπ+=3.8±1.1±0.4±0.2 and B+c→J/ψD∗+s/B+c→J/ψπ+=10.4±3.1±1.5±0.6, where the third error corresponds to the uncertainty of the branching fraction of D+s→ϕ(K+K−)π+ decay. The available theoretical predictions are generally consistent with the measurement.

Study of the $B_c^+ \rightarrow J/\psi D_s^+$ and $B_c^+ \rightarrow J/\psi D_s^*+$ decays with the ATLAS detector / Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Aben, R., Abolins, M., Abouzeid, O.S., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B.S., Adamczyk, L., Adams, D.L., Adelman, J., Adomeit, S., Adye, T., Affolder, A.A., Agatonovic Jovin, T., Aguilar Saavedra, J.A., et al.. - In: EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6052. - STAMPA. - C76:1(2016). [10.1140/epjc/s10052-015-3743-8]

Study of the $B_c^+ \rightarrow J/\psi D_s^+$ and $B_c^+ \rightarrow J/\psi D_s^*+$ decays with the ATLAS detector

Artoni, G.;BAGNAIA, Paolo;BAUCE, MATTEO;BINI, Cesare;DE CECCO, Sandro;DI DOMENICO, Antonio;GAUZZI, Paolo;GENTILE, Simonetta;GIAGU, Stefano;Kado, M.;LACAVA, Francesco;LUCI, Claudio;MESSINA, Andrea;Policicchio, A.;
2016

Abstract

The decays B+c→J/ψD+s and B+c→J/ψD∗+s 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 D(∗)+s→ϕπ+(γ/π0) decays. With a two-dimensional likelihood fit involving the B+c reconstructed invariant mass and an angle between the μ+ and D+s candidate momenta in the muon pair rest frame, the yields of B+c→J/ψD+s and B+c→J/ψD∗+s, and the transverse polarisation fraction in B+c→J/ψD∗+s decay are measured. The transverse polarisation fraction is determined to be Γ±±(B+c→J/ψD∗+s)/Γ(B+c→J/ψD∗+s)=0.38±0.23±0.07, and the derived ratio of the branching fractions of the two modes is B+c→J/ψD∗+s/B+c→J/ψD+s=2.8+1.2−0.8±0.3, where the first error is statistical and the second is systematic. Finally, a sample of B+c→J/ψπ+ decays is used to derive the ratios of branching fractions B+c→J/ψD+s/B+c→J/ψπ+=3.8±1.1±0.4±0.2 and B+c→J/ψD∗+s/B+c→J/ψπ+=10.4±3.1±1.5±0.6, where the third error corresponds to the uncertainty of the branching fraction of D+s→ϕ(K+K−)π+ decay. The available theoretical predictions are generally consistent with the measurement.
2016
01 Pubblicazione su rivista::01a Articolo in rivista
Study of the $B_c^+ \rightarrow J/\psi D_s^+$ and $B_c^+ \rightarrow J/\psi D_s^*+$ decays with the ATLAS detector / Aad, G., Abbott, B., Abdallah, J., Abdinov, O., Aben, R., Abolins, M., Abouzeid, O.S., Abramowicz, H., Abreu, H., Abreu, R., Abulaiti, Y., Acharya, B.S., Adamczyk, L., Adams, D.L., Adelman, J., Adomeit, S., Adye, T., Affolder, A.A., Agatonovic Jovin, T., Aguilar Saavedra, J.A., et al.. - In: EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6052. - STAMPA. - C76:1(2016). [10.1140/epjc/s10052-015-3743-8]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/948008
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