TWiki> Main Web>TWikiGroups>LHCbImperialGroup>LHCbImperialKMuMuSameSign>KMuMuSemileptonicBackgrounds (2011-04-13, unknown) EditAttachPDF
-- ThomasBlake - 01-Apr-2011

$B^{+} \rightarrow K^{-} \mu^{+} \mu^{+}$ semi-leptonic backgrounds

Decay mode BR fx / fu Fraction of events inside wide mass window Figure
$B_{c} \rightarrow J/\psi ( \rightarrow \mu^{+} \mu^{-}[K^{-}] ) \mu^{+} \nu_{\mu}$ $\mathcal{B}(B_{c}) = 5.2^{+2.4}_{-2.1} \times 10^{-5} $,$\mathcal{B}(J/\psi)=5.93\pm 0.06 \times 10^{-2}$ $f_{c}/f_{u}$ $0.273 \pm 0.002$  
$B^{+}_{u} \rightarrow \bar{D} (\rightarrow K^{+}[\mu^{+}] \pi^{-}[K^{-}]) \mu^{+} \nu_{\mu}$ $\mathcal{B}(B^{+}_{u}) = 2.23\pm0.11\times 10^{-2}$, $\mathcal{B}(D) = 3.89\pm0.05 \times 10^{-2}$ 1.0 $0.023 \pm 0.001$  
$B^{+}_{u} \rightarrow \bar{D} (\rightarrow \pi^{+}[\mu^{+}] K^{-}) \mu^{+} \nu_{\mu}$ $\mathcal{B}(B^{+}_{u}) = 2.23\pm0.11\times 10^{-2}$, $\mathcal{B}(D) = 1.48\pm0.07 \times 10^{-4}$ 1.0 $0.0033 \pm 0.0003$  
$B^{+}_{u} \rightarrow \bar{D} (\rightarrow \pi^{+} \pi^{-} [K^{-}]) \mu^{+} \nu_{\mu}$ $\mathcal{B}(B^{+}_{u}) = 2.23\pm0.11\times 10^{-2}$, $\mathcal{B}(D) = 1.397\pm0.026 \times 10^{-3}$ 1.0 $0.028 \pm 0.001$  
$B_{s} \rightarrow D^{-}_{s} (\rightarrow K^{+} \pi^{-}[\mu^{-}] \mu^{-} \bar{\nu}_{\mu}) \pi^{+} [K^{+}]$ $\mathcal{B}(B_{s}) = 3.2\pm0.5 \times 10^{-3}$, $\mathcal{B}(D^{-}_{s}) = \frac{2}{3} \times 1.8\pm0.7 \times 10^{-3} $ $f_{s}/f_{u}$    
$B_{s} \rightarrow D^{-}_{s} (\rightarrow K^{+} \pi^{-}[\mu^{-}] \mu^{-} \bar{\nu}_{\mu}) K^{+}$ $\mathcal{B}(B_{s}) = 3.0 \pm 0.7 \times 10^{-4}$, $\mathcal{B}(D^{-}_{s}) = \frac{2}{3} \times 1.8\pm0.7 \times 10^{-3} $ $f_{s}/f_{u}$    
$B^{+}_{u} \rightarrow \rho^{0} (\rightarrow \pi^{+}[\mu^{+}] \pi^{-}[K^{-}]) \mu^{+} \nu$ $\mathcal{B}(B^{+}_{u}) = 1.28\pm0.18\times 10^{-4}$,$\mathcal{B}(\rho^{0}) \sim \frac{2}{3}$ 1.0    

Note, the fraction of events in the signal mass window is calculated at generator level, i.e. does not include detector resolution. Detector resolution may result in 'bin migration' of candidates into the wide B mass window, but this effect should be negligible as $\sigma_{m_{B}}$ is tiny compared to the window size.

Decay mode coeff
$B_{c} \rightarrow J/\psi ( \rightarrow \mu^{+} \mu^{-}[K^{-}] ) \mu^{+} \nu_{\mu}$ $-0.000514 \pm 0.000053$
$B^{+}_{u} \rightarrow \bar{D} (\rightarrow K^{+}[\mu^{+}] \pi^{-}[K^{-}]) \mu^{+} \nu_{\mu}$ $-0.0027 \pm 0.00017$
$B^{+}_{u} \rightarrow \bar{D} (\rightarrow \pi^{+}[\mu^{+}] K^{-}) \mu^{+} \nu_{\mu}$ $-0.0087 \pm 0.0007$
$B^{+}_{u} \rightarrow \bar{D} (\rightarrow \pi^{+} \pi^{-} [K^{-}]) \mu^{+} \nu_{\mu}$ $ -0.00344676 \pm 0.000105914$
$B_{s} \rightarrow D^{-}_{s} (\rightarrow K^{+} \pi^{-}[\mu^{-}] \mu^{-} \bar{\nu}_{\mu}) \pi^{+} [K^{+}]$  
$B_{s} \rightarrow D^{-}_{s} (\rightarrow K^{+} \pi^{-}[\mu^{-}] \mu^{-} \bar{\nu}_{\mu}) K^{+}$  
$B^{+}_{u} \rightarrow \rho^{0} (\rightarrow \pi^{+}[\mu^{+}] \pi^{-}[K^{-}]) \mu^{+} \nu$  

$B^{+}_{u} \rightarrow \bar{D} (\rightarrow \pi^{+} \pi^{-} [K^{-}]) \mu^{+} \nu_{\mu}$

  • B_Dmunu_Dpipi.png:
    B_Dmunu_Dpipi.png

$B_{c} \rightarrow J/\psi ( \rightarrow \mu^{+} \mu^{-}[K^{-}] ) \mu^{+} \nu_{\mu}$

  • Bc_Jpsimunu.png:
    Bc_Jpsimunu.png

$B^{+}_{u} \rightarrow \bar{D} (\rightarrow \pi^{+}[\mu^{+}] K^{-}) \mu^{+} \nu_{\mu}$ -- DCS D decay

  • Bu_Dmu_DDCS.png:
    Bu_Dmu_DDCS.png

$B^{+}_{u} \rightarrow \bar{D} (\rightarrow K^{+}[\mu^{+}] \pi^{-}[K^{-}]) \mu^{+} \nu_{\mu}$

  • Bu_Dmunu_Kpi_usingK.png:
    Bu_Dmunu_Kpi_usingK.png

$B_{c}$ production

Leading $gg \rightarrow B_{c}^{+}b\bar{c}$ processes simulated in LHCb using BVECPY. Expect $f_{u}/f_{c} \sim 1000$. LHCb measures $R_{c} = [\sigma(B_{c}^{+}) \mathcal{B}(B^{+}_{c} \rightarrow J/\psi \pi^{+})]/[\sigma(B_{u}^{+}) \mathcal{B}(B^{+}_{u} \rightarrow J/\psi K^{+})] \sim 2\% $.

CDF (in CDF Note 7649) measure: $R_{c} = [\sigma(B_{c}^{+}) \mathcal{B}(B^{+}_{c} \rightarrow J/\psi \mu^{+} \nu_{\mu})]/[\sigma(B_{u}^{+}) \mathcal{B}(B^{+}_{u} \rightarrow J/\psi K^{+})] = 0.245 \pm 0.045(\mathrm{stat.}) \pm 0.066(\mathrm{syst.}) + 0.080-0.032(\mathrm{lifetime}) $

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PNGpng B_Dmunu_Dpipi.png r1 manage 11.5 K 2011-04-13 - 16:13 UnknownUser  
PNGpng Bc_Jpsimunu.png r1 manage 11.7 K 2011-04-13 - 16:13 UnknownUser  
PNGpng Bu_Dmu_DDCS.png r1 manage 9.2 K 2011-04-13 - 16:14 UnknownUser  
PNGpng Bu_Dmunu_Kpi_usingK.png r1 manage 10.6 K 2011-04-13 - 16:14 UnknownUser  
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Topic revision: r2 - 2011-04-13 - unknown
 
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