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Measurement of the inclusive differential jet cross section in pp collisions at $\sqrt{s}$ = 2.76 TeV

ALICE Collaboration

TL;DR

This paper reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at $\sqrt{s}=2.76$ TeV with the ALICE detector, providing a crucial reference for heavy-ion jet studies and a test of pQCD. Jets are reconstructed with the anti-$k_T$ algorithm for radii $R=0.2$ and $R=0.4$ and corrected to the particle level, with careful treatment of trigger biases and underlying-event contributions. The results are compared to Next-to-Leading Order pQCD calculations, showing good agreement when hadronization is included, and the cross-section ratio between the two radii offers insight into jet substructure and radiation patterns. This measurement, also consistent with prior 7 TeV data, strengthens the empirical foundation for jet physics at LHC energies and informs future jet-quenching studies in heavy-ion collisions at the same energy.

Abstract

The ALICE collaboration at the CERN Large Hadron Collider reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at $\sqrt{s} = 2.76$ TeV, with integrated luminosity of 13.6 nb$^{-1}$. Jets are measured over the transverse momentum range 20 to 125 GeV/c and are corrected to the particle level. Calculations based on Next-to-Leading Order perturbative QCD are in good agreement with the measurements. The ratio of inclusive jet cross sections for jet radii $R = 0.2$ and $R = 0.4$ is reported, and is also well reproduced by a Next-to-Leading Order perturbative QCD calculation when hadronization effects are included.

Measurement of the inclusive differential jet cross section in pp collisions at $\sqrt{s}$ = 2.76 TeV

TL;DR

This paper reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at TeV with the ALICE detector, providing a crucial reference for heavy-ion jet studies and a test of pQCD. Jets are reconstructed with the anti- algorithm for radii and and corrected to the particle level, with careful treatment of trigger biases and underlying-event contributions. The results are compared to Next-to-Leading Order pQCD calculations, showing good agreement when hadronization is included, and the cross-section ratio between the two radii offers insight into jet substructure and radiation patterns. This measurement, also consistent with prior 7 TeV data, strengthens the empirical foundation for jet physics at LHC energies and informs future jet-quenching studies in heavy-ion collisions at the same energy.

Abstract

The ALICE collaboration at the CERN Large Hadron Collider reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at TeV, with integrated luminosity of 13.6 nb. Jets are measured over the transverse momentum range 20 to 125 GeV/c and are corrected to the particle level. Calculations based on Next-to-Leading Order perturbative QCD are in good agreement with the measurements. The ratio of inclusive jet cross sections for jet radii and is reported, and is also well reproduced by a Next-to-Leading Order perturbative QCD calculation when hadronization effects are included.

Paper Structure

This paper contains 7 sections, 1 equation, 4 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Detector and Data Set
  3. Jet Reconstruction and Trigger Bias
  4. Correction to Particle Level
  5. Results
  6. Summary
  7. The ALICE Collaboration

Figures (4)

  • Figure 1: Jet neutral energy fraction (NEF) distributions for MB data (open squares), EMCal-triggered data (filled circles) and simulations (histograms), in four different $p_{\mathrm{T,jet}}$ intervals.
  • Figure 2: Simulated detector response to jets. Upper panels: probability distribution of $\left(p_\mathrm{T,jet}^\mathrm{detector}-p_\mathrm{T,jet}^\mathrm{particle}\right)/p_\mathrm{T,jet}^\mathrm{particle}$, in intervals of $p_\mathrm{T,jet}^\mathrm{particle}$. Lower left: mean and median of distribution as a function of $p_\mathrm{T,jet}^\mathrm{particle}$. Lower right: standard deviation of distribution as a function of $p_\mathrm{T,jet}^\mathrm{particle}$. The statistical errors are smaller than the marker size.
  • Figure 3: Upper panels: inclusive differential jet cross sections for $R$ = 0.2 (left) and $R$ = 0.4 (right). Vertical bars show the statistical error, while boxes show the systematic uncertainty (Table \ref{['tab:Table2']}). The bands show the NLO pQCD calculations discussed in the text ArmestoSoyez:2011np. Lower panels: ratio of NLO pQCD calculations to data. Data points are placed at the center of each bin.
  • Figure 4: Ratio of inclusive differential jet cross sections for $R$ = 0.2 and $R$ = 0.4, with pQCD calculations from Soyez:2011np. Data points are placed at the center of each bin.