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Measurement of the forward-central bbˉ production asymmetry

The conference note is available here

More detailed information: ANA note 2013-007

Abstract

A measurement of the forward-central bbˉ production asymmetry is reported based on data collected by {\mbox{LHCb}\xspace} in 2011 at √s=7TeV corresponding to an integrated luminosity of 1.0~fb−1. Events are selected that have two identified b jets, one of which is flavor tagged by the presence of a displaced muon with high momentum. The following results are obtained:

AbbˉFC=(0.50.5(stat)0.5(syst))%,

AbbˉFC(Mbbˉ>100 GeV)=(4.31.7(stat)2.4(syst) )%.

The asymmetry in the high-mass region is not corrected for the bbˉ mass resolution. Studies of simulated data estimate the dilution due to the di-jet mass resolution to be a few percent.

Figures

(Note, eps versions are available under attachments).

Caption Figure Sorted descending
Observed y distributions for events with measured Mbb > 100 GeV. The dashed distribution (mirror data) corresponds to delta y -> - delta y Fig5b.png
Observed y distributions for all events. The dashed distribution (mirror data) corresponds to delta y -> - delta y Fig5a.png
Observed time dependence of the tagging purity (black points). The (solid blue) curve is the predicted distribution obtained from simulation and has no free parameters Fig4.png
Observed (black solid) pseudo-lifetime distribution of flavor-tagged b jets. The signal shape (red dashed) is taken from simulation, while the background shape (blue dotted) is assumed to be uniform. The background is estimated to be O(0.2%) Fig3.png
Distributed B candidate masses for B+->D0pi+ decays used in the flavor-tagging study. Asymmetric Gaussian distributions are used for the signal PDFs; the combinatorial backgrounds are taken to be exponential, while the PDF of the partially-reconstructed background in B+->D0pi+ is obtained from simulation Fig2b.png
Distributed B candidate masses for B->J/psi K+ decays used in the flavor-tagging study. Asymmetric Gaussian distributions are used for the signal PDFs; the combinatorial backgrounds are taken to be exponential Fig2a.png
Di-jet b bbar mass distributions for (solid black) all events, (dashed red) flavor-tagged events and (dotted blue) doubly- flavor-tagged events. Fig1.png
Topic attachments
I Attachment History Action Size Date Who Comment
Unknown file formateps Fig1.eps r1 manage 9.4 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig1.png r1 manage 85.1 K 2013-04-05 - 20:06 TaraShears  
Unknown file formateps Fig2a.eps r1 manage 16.5 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig2a.png r1 manage 95.1 K 2013-04-05 - 20:06 TaraShears  
Unknown file formateps Fig2b.eps r1 manage 21.9 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig2b.png r1 manage 127.1 K 2013-04-05 - 20:06 TaraShears  
Unknown file formateps Fig3.eps r1 manage 9.4 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig3.png r1 manage 86.2 K 2013-04-05 - 20:06 TaraShears  
Unknown file formateps Fig4.eps r1 manage 7.3 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig4.png r1 manage 70.7 K 2013-04-05 - 20:06 TaraShears  
Unknown file formateps Fig5a.eps r1 manage 7.1 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig5a.png r1 manage 75.7 K 2013-04-05 - 20:06 TaraShears  
Unknown file formateps Fig5b.eps r1 manage 7.3 K 2013-04-05 - 20:06 TaraShears  
PNGpng Fig5b.png r1 manage 81.2 K 2013-04-05 - 20:06 TaraShears  
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Topic revision: r3 - 2014-01-17 - KatharinaMueller
 
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