Inclusive jets and dijets in LHCb

The paper is available here (LHCb-CONF-2011-015).

LHCB-CONF-2011-015

Abstract

The region η > 3 is a kinematic range of interest for Higgs searches, QCD physics and beyond the Standard Model studies in pp interactions at TeV energies. We explore the feasibility of measuring jets in the LHCb experiment, mainly devoted to precision measurements in the b-physics domain, but covering the very forward region 2 < η < 4.5. The jets reconstruction capabilities of LHCb are presented, together with some preliminary results on inclusive jets and dijets that show the potential interest of LHCb results for low-x/high-Q2 perturbative QCD tests. The data have been taken at LHC during the 2010 runs at √s = 7 TeV.

Figures

(eps versions are available under attachments).

Caption Sorted ascending Figure
Figure 1: Region in the (x, Q2 ) plane accessible to LHCb (adapted from Ref. [7]). fig1.png
Figure 2: Some illustrative events reconstructed in LHCb where the leading jet has pTjet >10 GeV/c from very early runs at 7 TeV. One of the runs on which we have tested the selection criteria. Jets reconstruction has been done with the kT algorithm in the E-recombination scheme with R = 1 and pTcut = 1 GeV/c. As “Underlying Event” (yellow) we classify any particle non clustered in the two jets with higher momentum, while “noise” is any track with χ2 /dof ≥ 10. fig2a.pngfig2b.pngfig2c.pngfig2d.png
Figure 3: Normalized differential raw transverse energy distribution compared with that obtained applying the kT algorithm to particles simulated with the LHCb Monte Carlo program (see text). fig3.png
Figure 4: Distribution of the azimuthal angle difference ∆φ = φjet1 − φjet2 for the two leading jets in all events that have at least two jets with pT > 20 GeV/c. The peak at ∆φ ≈ π is evident. The full line is the result of the fit of the data with the sum of a polynomial background (dashed line) and a Gaussian function. fig4.png
Figure 5: Differential distribution of the asymmetry parameter A, defined by Eq. (2), for the events in which the two jets have |∆φ − π |< 40◦. fig5.png
Figure 6: Invariant mass distribution for jet pairs with pT 1 and pT 2 ≥ 20 GeV/c, |∆φ − π |≤ 40◦ and A ≤ 0.2. The dashed histogram shows the LHCb-MC (see text) simulated distribution. fig6.png
Figure 7: Range in (x ̃, Q ̃2 ), defined in the text, that could be experimentally accessible to LHCb through the measurement of dijets at √s = 7 TeV. fig7.png
Figure 8: Dijet x ̃ distribution for various Q ̃2 ranges. fig8.png
-- KatharinaMueller - 16 Jan 2014
Topic attachments
I Attachment History Action Size Date Who Comment
Unknown file formateps fig1.eps r1 manage 4347.5 K 2014-01-16 - 12:10 KatharinaMueller  
PNGpng fig1.png r1 manage 73.5 K 2014-01-16 - 12:10 KatharinaMueller  
Unknown file formateps fig2a.eps r1 manage 656.0 K 2014-01-16 - 12:10 KatharinaMueller  
PNGpng fig2a.png r1 manage 21.6 K 2014-01-16 - 12:10 KatharinaMueller  
Unknown file formateps fig2b.eps r1 manage 656.0 K 2014-01-16 - 12:10 KatharinaMueller  
PNGpng fig2b.png r1 manage 19.9 K 2014-01-16 - 12:10 KatharinaMueller  
Unknown file formateps fig2c.eps r1 manage 656.0 K 2014-01-16 - 12:10 KatharinaMueller  
PNGpng fig2c.png r1 manage 22.1 K 2014-01-16 - 12:10 KatharinaMueller  
Unknown file formateps fig2d.eps r1 manage 656.0 K 2014-01-16 - 12:10 KatharinaMueller  
PNGpng fig2d.png r1 manage 21.6 K 2014-01-16 - 12:10 KatharinaMueller  
Unknown file formateps fig3.eps r1 manage 20.3 K 2014-01-16 - 12:11 KatharinaMueller  
PNGpng fig3.png r1 manage 36.2 K 2014-01-16 - 12:11 KatharinaMueller  
Unknown file formateps fig4.eps r1 manage 12.7 K 2014-01-16 - 12:11 KatharinaMueller  
PNGpng fig4.png r1 manage 21.1 K 2014-01-16 - 12:11 KatharinaMueller  
Unknown file formateps fig5.eps r1 manage 11.0 K 2014-01-16 - 12:11 KatharinaMueller  
PNGpng fig5.png r1 manage 14.7 K 2014-01-16 - 12:11 KatharinaMueller  
Unknown file formateps fig6.eps r1 manage 15.4 K 2014-01-16 - 12:11 KatharinaMueller  
PNGpng fig6.png r1 manage 26.1 K 2014-01-16 - 12:11 KatharinaMueller  
Unknown file formateps fig7.eps r1 manage 66.2 K 2014-01-16 - 12:11 KatharinaMueller  
PNGpng fig7.png r1 manage 23.8 K 2014-01-16 - 12:11 KatharinaMueller  
Unknown file formateps fig8.eps r1 manage 26.2 K 2014-01-16 - 12:11 KatharinaMueller  
PNGpng fig8.png r1 manage 24.5 K 2014-01-16 - 12:11 KatharinaMueller  
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