B-physics related plots from the CSC book

This page contains approved plots and results in the order as they appear in the CSC note. Only the CSC note contains all the relevant information and should thus be consulted if any of the plots is used.

Reconstruction of Λb - J/ψ( μ+μ−) Λ signal

Λb polarization, and helicity parameters with 5 fb-1

Λb polarization and asymmetry parameter α with 30 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(mm) < 7.3 GeV , vertex fit c 2 < 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.

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 10: LVL2 and EF output rates for minimum bias events, LVL2 trigger efficiencies and numbers of expected BsDsA1(mu4) events without or with selection cuts. Rates set in italics are estimates based on the interpolated and extrapolated rates given in Table 7. LVL2 output rates marked by ^α are downscaled by a factor two, the estimated rate reduction for a D_s vertex requirement at LVL2. For EF output rates marked by ^β, an estimated rate reduction factor of 60 accounting for EF B_s reconstruction is applied. (See section 3.5 for details.) The results in the columns "LVL2 eff." and N_{LVL2 output}^BsDsAs (without and with selection cuts applied) are based on the BsDsAs(mu4) Monte Carlo data sample. Numbers marked by ^# are corrected for the estimated efficiency loss by a D_s vertex requirement at LVL2. The integrated luminosities and expected event numbers correspond to one year running at the given instantaneous luminosity (10⁷ seconds).

(a) (b)
(c) (d)

Figure 6: Wrong tag fraction as functions of tagging muons transverse momentum p_T(μ) in (a) and (b) and wrong tag fractions as functions of signal Monte Carlos B_s transverse momentum p_T(B_s) in (c) and (d). The wrong tag fraction is shown with mixing of the tagging side b hadron and without mixing. Without mixing, the different sources of wrong tags are shown. The main contribution is coming from b→c→μ followed by additional c pairs. Additional sources shown are muons coming from J/ψ, φ, ρ, η and τ.

(a) (b)

Figure 10: m_KKππ (a) and m_KKππππ (b) reconstructed mass for signal and background channels. In (b) the upper limit for the branching fraction of the channel B_d→D_sa₁ is used.

(a) (b)

Figure 17: The B_s oscillation amplitude (a) and the measurement significance (b) as a function of Δ m_s for an integrated luminosity of 10 fb^-1 for a specific Monte Carlo experiment with Δ m_sgen = 100 ps^-1.

(a) (b)

Figure 18: The dependence of Δ m_s measurement limits (a) on the integrated luminosity and (b) on Δ Γ_s/ Γ_s for an integrated luminosity of 10 fb^-1. The dashed horizontal line in (a) denotes the CDF measurement.

(a) (b)

Figure 19: (a) The negative natural logarithm of the likelihood for a specific Monte Carlo data sample for an integrated luminosity of 10 fb^-1 and a true value of Δ m_s^gen = 17.77 ps^-1. The inset shows a zoom around the minimum. (b) The statistical error σ _stat ( Δ m_s ) as a function of the integrated luminosity for values of Δ m_s^gen of 15, 17.77 and 20 ps^-1. For comparison: the CDF statistical error on their Δ m_s measurement is 0.10 ps^-1