Study of the rare decay B_s⁰ to mu+mu- in ATLAS Plots and Tables

Figure 4: Transverse decay length of reconstructed B0s candidates. The signal is shown as closed circles, background as opened circles. Distributions are normalised to 1. The vertical line indicates the lowest transverse decay length allowed for selected events.

Figure 5: Distribution of isolation variable Imm for the reconstructed B0s candidates. The signal is shown as closed circles, background as opened circles. Distributions are normalised to 1. The vertical line indicates the lowest values of variable Imm allowed for selected events.

Figure 6: Distribution of pointing angle a for the reconstructed B0s candidates. The signal is shown as closed circles, background as opened circles. Distributions is normalised to 1. The vertical line indicates the highest values of a allowed for selected events.

Figure 7: The Monte Carlo di-muon mass distributions for signal B0s →μ+μ− (histogram), combinatorial background (closed circles) and non-combinatorial background (open circles and triangles) for (a) preselected events, (b) after cuts on transverse decay length, (c) pointing angle and (d) isolation. The number of events has been scaled to 10 fb⁻¹ of integrated luminosity.

Figure 8: Dimuon mass distribution for surviving events after applying all three cuts. The signal is shown as histogram, combinatorial background by closed circles and non-combinatorial backgrounds by opened circles and triangles. The combinatorial background is estimated assuming a factorisation of applied cuts. Statistics are given for an integrated luminosity 10 fb⁻¹.

Table 5: Selection efficiencies and number of signal and background events for integrated luminosity
of 10 fb⁻¹. Preselection criteria used: 4 GeV < M(μμ) < 7.3 GeV , vertex fit c χ² < 10 , transverse
decay length Lxy < 20 mm. Numbers of expected events are computed according to the Standard Model
expectation. In the left column for the b¯b mmX background the efficiencies are given separately for
each cut, in the right column the combined efficiency is given for the cuts on the pointing angle and on
the transverse decay length.