Articulo
Measurement of the parity-violating asymmetry parameter αb and the helicity amplitudes for the decay Λ<sup>0</sup>b →j /ψ Λ<sup>0</sup> with the ATLAS detector
Autor
Alconada Verzini, María Josefina
Alonso, Francisco
Anduaga, Xabier Sebastián
Dova, María Teresa
Monticelli, Fernando Gabriel
Tripiana, Martín Fernando
The ATLAS Collaboration
Institución
Resumen
A measurement of the parity-violating decay asymmetry parameter, αb, and the helicity amplitudes for the decay Λ<sup>0</sup>b→J/ψ(μ+μ-)Λ<sup>0</sup>(pπ-) is reported. The analysis is based on 1400 Λ<sup>0</sup>b and Λ<sup>0</sup>¯b 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 Λb0 and Λ<sup>0</sup>¯b samples under the assumption of CP conservation, the value of αb 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. La lista completa de autores que integran el documento puede consultarse en el archivo. Instituto de Física La Plata