Measurements of the Bc Production Cross Section and Lifetime Using Bc→J/ψeν Channel

Measurements of the Bc Production Cross Section and Lifetime Using Bc→J/ψeν Channel

This web page summarizes the result of Bc production cross section and lifetime analysis using Bc → J/ψ eν channel.

A complete summary of this results can be found here: ps.

Below are the eps files of figures and tables for download.

Production cross section analysis
σ(Bc)BR(Bc→J/ψeν)/σ(B⁺)BR(B⁺→J/ψK⁺) (pT(B)>4.0 GeV/c,|y|<1.0)
= 0.282 ± 0.038(stat.) ± 0.035(yield) ± 0.065(acceptance)

dE/dx

Figure, dE/dx cut efficiency plot
Table, dE/dx cut efficiency table
(cut value : Ze/σ > -1.3 , where Ze=ln( dE/dx / expected for electron ))

electron ID
Figure, Likelihood ratio distribution
(L = Π PDF(e) / (Π PDF(e) + Π PDF(π)) )
Figure, Normalized cumulative likelihood function(Pe) distribution
(Pe = ∫_L'¹dL Le(L) / ∫₀¹dL Le(L)
, where L' is obtained likelihood ratio,
Le(L) is likelihood ratio distribution for electron sample.
Pe < 0.7 cut is chosen in our analysis.)
Figure, Averaged fake rate plot
Table, Averaged fake rate table
Figure, Electron ID efficiency plot
Table, Electron ID efficiency table
Figure, D⁰→Kπ mass before/after eID cut on pion track
Figure, D⁰→Kπ mass before/after eID cut on kaon track
Figure, Λ⁰→Pπ mass before/after eID cut on proton track

Conversion
Figure, Conversion finding efficiency plot
Table, Conversion finding efficiency table

Mass distributions
Figure, J/ψ+fake e
Figure, J/ψ+residual conversion
Figure, b-bbar
Figure, J/ψ+e
Table, Summary of signal candidates
For normalizaiton
Figure, Mass(B⁺ → J/ψ K⁺)
Systematic uncertainties
Table, Systematic errors on yield
Table, Systematic errors on acceptance ratio

Lifetime analysis
τ(Bc) = 0.474 +0.073/-0.066(stat.) ± 0.033(syst.) ps

Figure, Invariant J/ψ+e mass distribution for data and partially estimated backgrounds
Table, J/ψ+e candidates and partially estimated backgrounds
Figure, K factor distribution (M(J/ψ+e)=4∼6GeV/c^2 region)
Figure, K factor distribution (M(J/ψ+e)=4∼4.5, 4.5∼5, 5∼5.5, 5.5∼6 GeV/c^2 region)
Background lifetime distribution
- Figure, fake electron
- Figure, conversion electron
- Figure, fake J/ψ
- Figure, b-bbar
J/psi+e data fit
- Figure, J/ψ+e with each BKG
- Figure, J/ψ+e with signal and total BKG
- Figure, J/ψ+e with signal and total BKG (linear scale)
- Table, J/ψ+e data fit result
Table, Systematic error on the Bc lifetime
Figure, J/ψ+e mass distribution(1)
Figure, J/ψ+e mass distribution(2)