A measurement of the parity-violating decay asymmetry parameter, α_b, and the helicity amplitudes for the decay Λ_0b → J/ψ(μμ)Λ_0(pπ) is reported. The analysis is based on 1400 Λ_0b and Λ¯_0b baryons selected in 4.6 fb−1 of proton–proton collision data with a center-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. By combining the Λ_0b and Λ¯_0b and samples under the assumption of CP conservation, the value of α_b is measured to be 0.30+- 0.16(stat)+- 0.06(syst). This measurement provides a test of theoretical models based on perturbative QCD or heavy-quark effective theory.
Measurement of the parity-violating asymmetry parameter α_b and the helicity amplitudes for the decay Λ_0b→J/ψΛ_0 with the ATLAS detector
CONTA, CLAUDIO;FRANCHINO, SILVIA;FRATERNALI, MARCO;LIVAN, MICHELE;NEGRI, ANDREA;REBUZZI, DANIELA MARCELLA;RIMOLDI, ADELE;
2014-01-01
Abstract
A measurement of the parity-violating decay asymmetry parameter, α_b, and the helicity amplitudes for the decay Λ_0b → J/ψ(μμ)Λ_0(pπ) is reported. The analysis is based on 1400 Λ_0b and Λ¯_0b baryons selected in 4.6 fb−1 of proton–proton collision data with a center-of-mass energy of 7 TeV recorded by the ATLAS experiment at the LHC. By combining the Λ_0b and Λ¯_0b and samples under the assumption of CP conservation, the value of α_b is measured to be 0.30+- 0.16(stat)+- 0.06(syst). This measurement provides a test of theoretical models based on perturbative QCD or heavy-quark effective theory.File in questo prodotto:
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