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-- BenoitRoland - 26-Mar-2012

Abstract

The underlying event activity in proton-proton collisions at forward pseudorapidity () is studied with the CMS detector at the LHC, using a novel observable: the ratio of the forward energy density, dE/dη, for events with a charged-particle jet produced at central pseudorapidity () to the forward energy density for inclusive events. This forward energy density ratio is measured as a function of the central jet transverse momentum, , at three different pp centre-of-mass energies ( √s = 0.9, 2.76, and 7 TeV). In addition, the √s evolution of the forward energy density is studied in inclusive events and in events with a central jet. The results are compared to those of Monte Carlo event generators for pp collisions and are discussed in terms of the underlying event. Whereas the dependence of the forward energy density ratio on jet at each √s separately can be well reproduced by some models, all models fail to simultaneously describe the increase of the forward energy ￼￼density with √s in both inclusive events and in events with a central jet.

Comparisons to PYTHIA and HERWIG predictions (Paper) (click on plot to get .pdf)

Figure
Ratio of the energy deposited in the pseudorapidity range for events with a charged particle jet with with respect to the energy in inclusive events, as a function of charged particle jet transverse momentum for 0.9 (left), 2.76 (middle), and 7 TeV (right). Corrected results are compared to the PYTHIA and HERWIG++ MC models. Error bars indicate the statistical error on the data points, while the grey band around data points represents the statistical and systematic uncertainties added in quadrature.

 Energy density in the pseudorapidity range in inclusive events (left) and in events with a charged-particle jet in the range (right) as a function of , normalized to the energy density at 2.76 TeV. The threshold used for jets is 10 GeV/c at all centre-of-mass energies. Corrected results are compared to the PYTHIA and HERWIG++ MC models. Statistical errors are smaller than the markers size, while the grey band around data points represents the statistical and systematic uncertainties added in quadrature.

Comparisons to Cosmic Ray, CASCADE and DIPSY model predictions (Paper) (click on plot to get .pdf)

Figure
Ratio of the energy deposited in the pseudorapidity range for events with a charged particle jet with with respect to the energy in inclusive events, as a function of charged particle jet transverse momentum for 0.9 (left), 2.76 (middle), and 7 TeV (right). Corrected results are compared to MC models used in cosmic ray physics and to CASCADE and DIPSY. Error bars indicate the statistical error on the data points, while the grey band around data points represents the statistical and systematic uncertainties added in quadrature.

 Energy density in the pseudorapidity range in inclusive events (left) and in events with a charged-particle jet in the range (right) as a function of , normalized to the energy density at 2.76 TeV. The threshold used for jets is 10 GeV/c at all centre-of-mass energies. Corrected results are compared to MC models used in cosmic ray physics and to CASCADE and DIPSY. Statistical errors are smaller than the markers size, while the grey band around data points represents the statistical and systematic uncertainties added in quadrature.

Detector level cuts versus particle level selection (extra public material) (click on plot to get .pdf)

Figure Caption
vs. for all generated events (orange) and for generated events selected at the detector level (blue) for 7 TeV. Single diffractive dissociation events have a or value equal to ( at 7 TeV), while double diffractive dissociation and non-diffractive events have and values ranging from 0 to 1. The green lines indicate the particle level cuts. At the particle level, all events to the top and to the right of the green lines are selected.
Topic attachments
I Attachment History Action Size Date Who Comment
pdf CmPlots.pdf r1 manage 16.6 K 2013-02-13 - 17:15 HansVanHaevermaet
png CmPlots.png r1 manage 92.4 K 2013-02-13 - 17:13 HansVanHaevermaet
pdf CmPlots_cosmicray.pdf r1 manage 16.7 K 2013-02-13 - 17:14 HansVanHaevermaet
png CmPlots_cosmicray.png r1 manage 91.2 K 2013-02-13 - 17:13 HansVanHaevermaet
pdf PtPlots.pdf r1 manage 23.8 K 2013-02-13 - 17:15 HansVanHaevermaet
png PtPlots.png r1 manage 122.1 K 2013-02-13 - 17:14 HansVanHaevermaet
pdf PtPlots_cosmicray.pdf r1 manage 23.9 K 2013-02-13 - 17:15 HansVanHaevermaet
png PtPlots_cosmicray.png r1 manage 119.7 K 2013-02-13 - 17:14 HansVanHaevermaet
pdf Ratio_vs_pt_corrected_2760GeV_cosmicray_public.pdf r1 manage 16.5 K 2012-03-26 - 19:48 BenoitRoland
png Ratio_vs_pt_corrected_2760GeV_cosmicray_public.png r1 manage 16.5 K 2012-03-26 - 19:49 BenoitRoland
pdf Ratio_vs_pt_corrected_2760GeV_extra_public.pdf r1 manage 16.6 K 2012-03-26 - 20:11 BenoitRoland
png Ratio_vs_pt_corrected_2760GeV_extra_public.png r1 manage 17.1 K 2012-03-26 - 20:12 BenoitRoland
pdf Ratio_vs_pt_corrected_2760GeV_public.pdf r1 manage 16.5 K 2012-03-26 - 18:29 BenoitRoland
png Ratio_vs_pt_corrected_2760GeV_public.png r1 manage 16.9 K 2012-03-26 - 18:30 BenoitRoland
pdf Ratio_vs_pt_corrected_7TeV_cosmicray_public.pdf r1 manage 16.5 K 2012-03-26 - 19:48 BenoitRoland
png Ratio_vs_pt_corrected_7TeV_cosmicray_public.png r1 manage 17.4 K 2012-03-26 - 19:49 BenoitRoland
pdf Ratio_vs_pt_corrected_7TeV_extra_public.pdf r1 manage 16.6 K 2012-03-26 - 20:11 BenoitRoland
png Ratio_vs_pt_corrected_7TeV_extra_public.png r1 manage 17.7 K 2012-03-26 - 20:13 BenoitRoland
pdf Ratio_vs_pt_corrected_7TeV_public.pdf r1 manage 16.4 K 2012-03-26 - 18:30 BenoitRoland
png Ratio_vs_pt_corrected_7TeV_public.png r1 manage 17.8 K 2012-03-26 - 18:31 BenoitRoland
pdf Ratio_vs_pt_corrected_900GeV_cosmicray_public.pdf r1 manage 16.5 K 2012-03-26 - 19:48 BenoitRoland
png Ratio_vs_pt_corrected_900GeV_cosmicray_public.png r1 manage 16.7 K 2012-03-26 - 19:49 BenoitRoland
pdf Ratio_vs_pt_corrected_900GeV_extra_public.pdf r1 manage 16.7 K 2012-03-26 - 20:11 BenoitRoland
png Ratio_vs_pt_corrected_900GeV_extra_public.png r1 manage 17.5 K 2012-03-26 - 20:12 BenoitRoland
pdf Ratio_vs_pt_corrected_900GeV_public.pdf r1 manage 16.5 K 2012-03-26 - 18:29 BenoitRoland
png Ratio_vs_pt_corrected_900GeV_public.png r1 manage 17.2 K 2012-03-26 - 18:30 BenoitRoland
pdf RelativeEflow_vs_cmenergy_cosmicray_public.pdf r1 manage 14.0 K 2012-03-26 - 19:48 BenoitRoland
png RelativeEflow_vs_cmenergy_cosmicray_public.png r1 manage 13.5 K 2012-03-26 - 19:49 BenoitRoland
pdf RelativeEflow_vs_cmenergy_extra_public.pdf r1 manage 14.1 K 2012-03-26 - 20:12 BenoitRoland
png RelativeEflow_vs_cmenergy_extra_public.png r1 manage 14.4 K 2012-03-26 - 20:13 BenoitRoland
pdf RelativeEflow_vs_cmenergy_public.pdf r1 manage 14.0 K 2012-03-26 - 18:30 BenoitRoland
png RelativeEflow_vs_cmenergy_public.png r1 manage 14.1 K 2012-03-26 - 18:31 BenoitRoland
pdf RelativeLeadingjetEflow_vs_cmenergy_cosmicray_public.pdf r1 manage 14.1 K 2012-03-26 - 19:49 BenoitRoland
png RelativeLeadingjetEflow_vs_cmenergy_cosmicray_public.png r1 manage 14.8 K 2012-03-26 - 19:50 BenoitRoland
pdf RelativeLeadingjetEflow_vs_cmenergy_extra_public.pdf r1 manage 14.2 K 2012-03-26 - 20:12 BenoitRoland
png RelativeLeadingjetEflow_vs_cmenergy_extra_public.png r1 manage 15.7 K 2012-03-26 - 20:13 BenoitRoland
pdf RelativeLeadingjetEflow_vs_cmenergy_public.pdf r1 manage 14.1 K 2012-03-26 - 18:30 BenoitRoland
png RelativeLeadingjetEflow_vs_cmenergy_public.png r1 manage 15.6 K 2012-03-26 - 18:31 BenoitRoland
pdf cutlines_7TeV.pdf r1 manage 698.0 K 2012-03-26 - 20:46 BenoitRoland
png cutlines_7TeV.png r1 manage 54.3 K 2012-03-26 - 20:49 BenoitRoland
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Topic revision: r2 - 2013-02-13 - HansVanHaevermaet

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