The first observation of the decays B_(s)^0→J/ψpp[over ¯] is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb^-1, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B(B^0→J/ψpp[over ¯])=[4.51±0.40(stat)±0.44(syst)]×10^-7, B(B_s^0→J/ψpp[over ¯])=[3.58±0.19(stat)±0.39(syst)]×10^-6. For the B_s^0 meson, the result is much higher than the expected value of O(10^-9). The small available phase space in these decays also allows for the most precise single measurement of both the B^0 mass as 5279.74±0.30(stat)±0.10(syst) MeV and the B_s^0 mass as 5366.85±0.19(stat)±0.13(syst) MeV.
Observation of B_(s)^0→J/ψpp[over ¯] Decays and Precision Measurements of the B_(s)^0 Masses
Veltri, M;
2019
Abstract
The first observation of the decays B_(s)^0→J/ψpp[over ¯] is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb^-1, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B(B^0→J/ψpp[over ¯])=[4.51±0.40(stat)±0.44(syst)]×10^-7, B(B_s^0→J/ψpp[over ¯])=[3.58±0.19(stat)±0.39(syst)]×10^-6. For the B_s^0 meson, the result is much higher than the expected value of O(10^-9). The small available phase space in these decays also allows for the most precise single measurement of both the B^0 mass as 5279.74±0.30(stat)±0.10(syst) MeV and the B_s^0 mass as 5366.85±0.19(stat)±0.13(syst) MeV.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
