This web page summarizes the results for the measurement the B_{c}^{±}
lifetime using the decay modes B_{c}^{±} → J/ψ+l^{±}+X,
where l^{±} is an electron or muon and X are unmeasured particles. The measurement is
done with in 1 fb^{-1} of exclusive J/ψ data.

We measure:

- cτ(B
_{c}) = 142.5 +15.8-14.8(stat.) ± 5.5 (syst.) μm - τ(B
_{c}) = 0.475 +0.053-0.049(stat.) ± 0.018 (syst.) ps

Top: ct

Below are the eps and jpeg versions of figures meant for download that are in the above note.

- Figure 1: J/ψ mass (.eps)(.jpg)
- Figure 2: J/ψ+μ mass - Monte Carlo of J/ψ+μ mass from B
_{c}decays (.eps)(.jpg) - Figure 3a: Particle fractions - J/ψ+track sample for muon channel, ct
^{*}<0 μm, third track Q=+1 (.eps)(.jpg) - Figure 3b: Particle fractions - J/ψ+track sample for muon channel, ct
^{*}<0 μm, third track Q=-1 (.eps)(.jpg) - Figure 3c: Particle fractions - J/ψ+track sample for muon channel, 0<ct
^{*}<150 μm, third track Q=+1 (.eps)(.jpg) - Figure 3d: Particle fractions - J/ψ+track sample for muon channel, 0<ct
^{*}<150 μm, third track Q=-1 (.eps)(.jpg) - Figure 3e: Particle fractions - J/ψ+track sample for muon channel, ct
^{*}>150 μm, third track Q=+1 (.eps)(.jpg) - Figure 3f: Particle fractions - J/ψ+track sample for muon channel, ct
^{*}>150 μm, third track Q=-1 (.eps)(.jpg) - Figure 4a: Particle fractions - J/ψ+track sample for electron channel, ct
^{*}<0 μm, third track Q=+1 (.eps)(.jpg) - Figure 4b: Particle fractions - J/ψ+track sample for electron channel, ct
^{*}<0 μm, third track Q=-1 (.eps)(.jpg) - Figure 4c: Particle fractions - J/ψ+track sample for electron channel, 0<ct
^{*}<150 μm, third track Q=+1 (.eps)(.jpg) - Figure 4d: Particle fractions - J/ψ+track sample for electron channel, 0<ct
^{*}<150 μm, third track Q=-1 (.eps)(.jpg) - Figure 4e: Particle fractions - J/ψ+track sample for electron channel, ct
^{*}>150 μm, third track Q=+1 (.eps)(.jpg) - Figure 4f: Particle fractions - J/ψ+track sample for electron channel, ct
^{*}>150 μm, third track Q=-1 (.eps)(.jpg) - Figure 5a: D
^{0}Mass - Fitted for event where π leg passes track cuts, 3<p_{T}<4 GeV/c^{2}(.eps)(.jpg) - Figure 5b: Λ - Fitted for event where p
^{-}leg passes track cuts, 2<p_{T}<3 GeV/c^{2}(.eps)(.jpg) - Figure 5c: D
^{0}Mass - Fitted for event where π leg passes track cuts and muon ID, 3<p_{T}<4 GeV/c^{2}(.eps)(.jpg) - Figure 5d: Λ - Fitted for event where p
^{-}leg passes track cuts and electron ID, 2<p_{T}<3 GeV/c^{2}(.eps)(.jpg) - Figure 6: Hadron faking muon probabilities (.eps)(.jpg)
- Figure 7a: Hadron faking e
^{+}probabilities (.eps)(.jpg) - Figure 7b: Hadron faking e
^{-}probabilities (.eps)(.jpg) - Figure 8a: Fitted J/ψ+fake μ ct
^{*}(.eps)(.jpg) - Figure 8b: Fitted J/ψ+fake e ct
^{*}(.eps)(.jpg) - Figure 9a: Fitted fake J/ψ+μ ct
^{*}(.eps)(.jpg) - Figure 9b: Fitted fake J/ψ+e ct
^{*}(.eps)(.jpg) - Figure 10: J/ψμ Δφ - Fitted azimuthal angle distribution between J/ψ and μ for data with no vertex probability cut.(.eps)(.jpg)
- Figure 11a: Impact parameter of third μ with respect to the J/ψ vertex for data with no vertex probability cut (expect signal excess in lowest 2 bins).(.eps)(.jpg)
- Figure 11b: Impact parameter of electron with respect to the J/ψ vertex for data with no vertex probability cut (expect signal excess in lowest 2 bins).(.eps)(.jpg)
- Figure 12a: Fitted bb(bar) J/ψ+μ ct
^{*}(.eps)(.jpg) - Figure 12b: Fitted bb(bar) J/ψ+e ct
^{*}(.eps)(.jpg) - Figure 13: e
^{+}e^{-}veto efficiency - From Pythia MC (.eps)(.jpg) - Figure 14: Fitted residual e
^{+}e^{-}J/ψ+e ct^{*}(.eps)(.jpg) - Figure 15a: K Factor for B
_{c}^{±}→ J/ψ+μ^{±}+X decays (.eps)(.jpg) - Figure 15b: K Factor for B
_{c}^{±}→ J/ψ+e^{±}+X decays (.eps)(.jpg) - Figure 16a: Fitted J/ψ+μ ct
^{*}- Fit to measure B_{c}lifetime (.eps)(.jpg) - Figure 16b: Fitted J/ψ+μ ct
^{*}- Fit to measure B_{c}lifetime (backgrounds drawn as one function)(.eps)(.jpg) - Figure 17a: Fitted J/ψ+e ct
^{*}- Fit to measure B_{c}lifetime (.eps)(.jpg) - Figure 17b: Fitted J/ψ+e ct
^{*}- Fit to measure B_{c}lifetime (backgrounds drawn as one function)(.eps)(.jpg) - Figure 18a: -2Log(L) for J/ψ+μ and J/ψ+e lifetime fits(.eps)(.jpg)
- Figure 18b: -2Log(L
_{e})-2Log(L_{μ}) - Combined for lifetime in J/ψ+l decays(.eps)(.jpg)

Below are the eps and jpeg versions of figures meant for download that are not in the above note.

- Figure 1: Fitted J/ψ+fake μ σ
_{ct*}(.eps)(.jpg) - Figure 2: Fitted J/ψ+fake e σ
_{ct*}(.eps)(.jpg) - Figure 3: Fitted fake J/ψ+μ σ
_{ct*}(.eps)(.jpg) - Figure 4: Fitted fake J/ψ+e σ
_{ct*}(.eps)(.jpg) - Figure 5: Fitted bb(bar) J/ψ+μ σ
_{ct*}(.eps)(.jpg) - Figure 6: Fitted bb(bar) J/ψ+e σ
_{ct*}(.eps)(.jpg) - Figure 7: Fitted residual e
^{+}e^{-}J/ψ+e σ_{ct*}(.eps)(.jpg) - Figure 8: Fitted J/ψ+track σ
_{ct*}for ct^{*}<0 μm - prompt model for muon channel (.eps)(.jpg) - Figure 9: Fitted J/ψ+track σ
_{ct*}for ct^{*}<0 μm - prompt model for electron channel (.eps)(.jpg) - Figure 10: σ
_{ct*}projection from B_{c}lifetime fit in J/ψ+μ channel (.eps)(.jpg) - Figure 11: σ
_{ct*}projection from B_{c}lifetime fit in J/ψ+μ channel (backgrounds drawn as one function)(.eps)(.jpg) - Figure 12: σ
_{ct*}projection from B_{c}lifetime fit in J/ψ+e channel (.eps)(.jpg) - Figure 13: σ
_{ct*}projection from B_{c}lifetime fit in J/ψ+e channel (backgrounds drawn as one function)(.eps)(.jpg) - Figure 14: J/ψ mass with trigger confirmation for J/ψ muon legs (.eps)(.jpg)
- Figure 15: TOF Projection - TOF+dE/dx fit to third track in J/ψ+track (electron channel), 0<ct
^{*}<150 μm, 2.0<p<2.5, Q=-1 (.eps)(.jpg) - Figure 16: dE/dx Projection - TOF+dE/dx fit to third track in J/ψ+track (electron channel), 0<ct
^{*}<150 μm, 2.0<p<2.5, Q=-1 (.eps)(.jpg) - Figure 17: dE/dx Fit - to third track in J/ψ+track (muon channel), ct
^{*}<0 μm, 4.5<p<5.0, Q=-1 (.eps)(.jpg) - Figure 18: Signed Impact Parameter - for electrons in J/ψ+e events with no vertex probability cut (.eps)(.jpg)
- Figure 19: Cross check of conversion veto efficiency using signed impact parameter(.eps)(.jpg)
- Figure 20: Radius of origin for e
^{+}e^{-}pairs in data J/ψ+e events with no vertex probability cut (.eps)(.jpg) - Figure 21: Radius of origin for e
^{+}e^{-}pairs in Pythia J/ψ+e events with no vertex probability cut (.eps)(.jpg) - Figure 22: J/ψ+μ mass for events with ct
^{*}>120 μm - Normalization of predicted components comes from B_{c}lifetime fit (.eps)(.jpg) - Figure 23: J/ψ+e mass for events with ct
^{*}>120 μm - Normalization of predicted components comes from B_{c}lifetime fit (.eps)(.jpg) - Figure 24: Comparison of B
_{c}cτ with most precise D0 and CDF Run I measurements. Includes unofficial world average. (.eps)(.jpg) - Figure 25: Electron likelihood ratio for pure sample of electrons. (.eps)(.jpg)
- Figure 26: Optimized electron likelihood ratio cut for electron selection. (.eps)(.jpg)
- Figure 27: Efficiency for the electron likelihood ratio cut. (.eps)(.jpg)