Measurement of σ(bbˉ) with inclusive final states

The conference note is available here (LHCb-CONF-2013-002)

More detailed information: ANA note 2012-022

Abstract

A measurement of the cross section for the production of bbˉ pairs based on b inclusive final states is presented using LHCb data collected from pp collisions at s√= 7 TeV in 2010, corresponding to an integrated luminosity of ∼18 pb−1. The inclusive bbˉ sample is selected on the basis of decay vertices displaced from the primary interaction. The measurement has been performed in a region of pseudorapidity 2.5 <η< 4.0 and transverse momentum pT >5 GeV of the b hadron candidate. The selected sample is a mixture of bbˉ and ccˉ events with a negligible contamination of light quarks, a measurement of the cross section for the production of ccˉ can therefore be performed simultaneously. The results are σbbˉ=7.70.12 (stat)0.84 (syst) μb and σccˉ=104.62.7 (stat)11.4 (syst) μb, inside the kinematic range defined above.

Figures

(Note, eps versions are available under attachments).

Caption Figure
∆ φ between the b̄b quark pairs: distributions are shown at the very first Pythia production step (continuous red line) and at the last step before hadronization (dotted black line). The distribution for the b hadron pairs is shown in the yellow filled histogram Fig1.png
Difference in azimuthal angles of the two b hadrons for Pythia at the LO approximation (black line) and Powheg at the NLO approximation (blue filled histogram) in the b̄b-inclusive events Fig2.png
Resolution in φ for the seed measured as described in the text for events with one b hadron and one reconstructed seed. Fig3a.png
Resolution in θ for the seed measured as described in the text for events with one b hadron and one reconstructed seed. Fig3b.png
Distribution of ∆φ of a seed pair before (black line) and after (red histogram) the merging procedure. Fig4.png
Correlations in η between the B0→D−π+ decay, and the seed reconstructed with the particles originating from the signal B0 Fig5a.png
Correlations in η between the B0→D−π+ decay and the seed reconstructed without the particles originating from the signal B0 Fig5b.png
Comparison of the transverse momentum of the seed before and after calibration (red histogram and black points respectively), and with true b hadrons (yellow filled histogram), in the fiducial region of the measurement. Distributions are normalized to unity Fig6.png
Distributions of ∆φ of the seeds. Data (black dots), b̄b(yellow light histogram), c̄c (blue dark histogram). Expected contributions of b̄b and c̄c are subsequently added Fig7a.png
Distributions of pT of the seeds. Data (black dots), b̄b(yellow light histogram), c̄c (blue dark histogram). Expected contributions of b̄b and c̄c are subsequently added Fig7b.png
Response of the BDTG (defined in the text) for data (black dots) fitted with shapes evaluated from simulated b̄b (red dotted line) and c̄c (green dashed line) events. The fit result is indicated by the solid blue line. Fig8.png
Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng Fig1.png r1 manage 20.8 K 2013-04-05 - 20:29 TaraShears  
Unknown file formateps Fig2.eps r1 manage 7.4 K 2013-04-05 - 20:29 TaraShears  
PNGpng Fig2.png r1 manage 13.5 K 2013-04-05 - 20:29 TaraShears  
Unknown file formateps Fig3a.eps r1 manage 9.5 K 2013-04-05 - 20:29 TaraShears  
PNGpng Fig3a.png r1 manage 20.5 K 2013-04-05 - 20:29 TaraShears  
Unknown file formateps Fig3b.eps r1 manage 9.1 K 2013-04-05 - 20:29 TaraShears  
PNGpng Fig3b.png r1 manage 18.9 K 2013-04-05 - 20:29 TaraShears  
Unknown file formateps Fig4.eps r1 manage 14.0 K 2013-04-05 - 20:29 TaraShears  
PNGpng Fig4.png r1 manage 19.3 K 2013-04-05 - 20:29 TaraShears  
Unknown file formateps Fig5a.eps r1 manage 49.5 K 2013-04-05 - 20:30 TaraShears  
PNGpng Fig5a.png r1 manage 31.8 K 2013-04-05 - 20:30 TaraShears  
Unknown file formateps Fig5b.eps r1 manage 53.4 K 2013-04-05 - 20:30 TaraShears  
PNGpng Fig5b.png r1 manage 33.5 K 2013-04-05 - 20:30 TaraShears  
Unknown file formateps Fig6.eps r1 manage 57.0 K 2013-04-05 - 20:30 TaraShears  
PNGpng Fig6.png r1 manage 52.9 K 2013-04-05 - 20:30 TaraShears  
Unknown file formateps Fig7a.eps r1 manage 13.4 K 2013-04-05 - 20:30 TaraShears  
PNGpng Fig7a.png r1 manage 21.4 K 2013-04-05 - 20:30 TaraShears  
Unknown file formateps Fig7b.eps r1 manage 13.4 K 2013-04-05 - 20:30 TaraShears  
PNGpng Fig7b.png r1 manage 20.7 K 2013-04-05 - 20:30 TaraShears  
Unknown file formateps Fig8.eps r1 manage 138.1 K 2013-04-05 - 20:31 TaraShears  
PNGpng Fig8.png r1 manage 55.4 K 2013-04-05 - 20:31 TaraShears  
Edit | Attach | Watch | Print version | History: r4 < r3 < r2 < r1 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r4 - 2014-03-10 - KatharinaMueller
 
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    LHCb All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2019 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback