The dependence of inclusive jet production in proton-proton collisions with a center-of-mass energy of 13 TeV on the distance parameter $R$ of the anti-$k_\mathrm{T}$ algorithm is studied using data corresponding to integrated luminosities up to 35.9 fb$^{-1}$ collected by the CMS experiment in 2016. The ratios of the inclusive cross sections as functions of transverse momentum $p_\mathrm{T}$ and rapidity $y$, for $R$ in the range 0.1 to 1.2 to those using $R = $ 0.4 are presented in the region 84 $\lt$ $p_\mathrm{T}$ $\lt$ 1588 GeV and $|y|$ $\lt$ 2.0. The results are compared to calculations at leading and next-to-leading order in the strong coupling constant using different parton shower models. The variation of the ratio of cross sections with $R$ is well described by calculations including a parton shower model, but not by a leading-order quantum chromodynamics calculation including nonperturbative effects. The agreement between the data and the theoretical predictions for the ratios of cross sections is significantly improved when next-to-leading order calculations with nonperturbative effects are used.
Ratio of differential cross section of AK1 jets with respect to AK4 jets a function of jet PT in the rapidity range |y|<0.5. The nonperturbative correction can be used to scale fixed-order theory prediction to compare to data at particle level.
Ratio of differential cross section of AK1 jets with respect to AK4 jets a function of jet PT in the rapidity range 0.5<|y|<1.0. The nonperturbative correction can be used to scale fixed-order theory prediction to compare to data at particle level.
Ratio of differential cross section of AK1 jets with respect to AK4 jets a function of jet PT in the rapidity range 1.0<|y|<1.5. The nonperturbative correction can be used to scale fixed-order theory prediction to compare to data at particle level.
We report the differential charged jet cross section and jet fragmentation distributions measured with the ALICE detector in proton-proton collisions at a centre-of-mass energy $\sqrt{s}=$ 7 TeV. Jets with pseudo-rapidity $\left| \eta \right| < {\rm 0.5}$ are reconstructed from charged particles using the anti-$k_{\rm T}$ jet finding algorithm with a resolution parameter $R$ = 0.4. The jet cross section is measured in the transverse momentum interval 5 $\leq p_{\rm T}^{\rm ch \; jet} <$ 100 GeV/$c$. Jet fragmentation is studied measuring the scaled transverse momentum spectra of the charged constituents of jets in four intervals of jet transverse momentum between 5 GeV/$c$ and 30 GeV/$c$. The measurements are compared to calculations from the PYTHIA model as well as next-to-leading order perturbative QCD calculations with POWHEG + PYTHIA8. The charged jet cross section is described by POWHEG for the entire measured range of $p_{\rm T}^{\rm ch \; jet}$. For $p_{\rm T}^{\rm ch \; jet}$ $>$ 40 GeV/$c$, the PYTHIA calculations also agree with the measured charged jet cross section. PYTHIA6 simulations describe the fragmentation distributions to 15%. Larger discrepancies are observed for PYTHIA8.
Measured charged jet differential cross sections for INEL proton-proton collisions at $\sqrt{s}$ = 7 TeV.
Measured charged jet differential cross section ratios for INEL proton-proton collisions at $\sqrt{s}$ = 7 TeV for $5<p_{T}^{ch jet}<10$ GeV/$c$.
Measured charged jet differential cross section ratios for INEL proton-proton collisions at $\sqrt{s}$ = 7 TeV for $10<p_{T}^{ch jet}<15$ GeV/$c$.
A measurement of the double-differential inclusive jet cross section as a function of jet transverse momentum pT and absolute jet rapidity |y| is presented. The analysis is based on proton-proton collisions collected by the CMS experiment at the LHC at a centre-of-mass energy of 13 TeV. The data samples correspond to integrated luminosities of 71 and 44 inverse picobarns for |y| < 3 and 3.2 < |y| < 4.7, respectively. Jets are reconstructed with the anti-kt clustering algorithm for two jet sizes, R, of 0.7 and 0.4, in a phase space region covering jet pT up to 2 TeV and jet rapidity up to |y| = 4.7. Predictions of perturbative quantum chromodynamics at next-to-leading order precision, complemented with electroweak and nonperturbative corrections, are used to compute the absolute scale and the shape of the inclusive jet cross section. The cross section difference in R, when going to a smaller jet size of 0.4, is best described by Monte Carlo event generators with next-to-leading order predictions matched to parton showering, hadronisation, and multiparton interactions. In the phase space accessible with the new data, this measurement provides a first indication that jet physics is as well understood at sqrt(s) = 13 TeV as at smaller centre-of-mass energies.
Inclusive Jet Cross Section for |rapidity| < 0.5 as a function of the jet transverse momentum. Jets are clustered with the anti-kt algorithm ( R = 0.7). The (sys) error is the total systematic error, including the luminosity uncertainty of 2.7%.
Inclusive Jet Cross Section for |rapidity| 0.5 TO 1.0 as a function of the jet transverse momentum. Jets are clustered with the anti-kt algorithm ( R = 0.7). The (sys) error is the total systematic error, including the luminosity uncertainty of 2.7%.
Inclusive Jet Cross Section for |rapidity| 1.0 TO 1.5 as a function of the jet transverse momentum. Jets are clustered with the anti-kt algorithm ( R = 0.7). The (sys) error is the total systematic error, including the luminosity uncertainty of 2.7%.
Measurements of charged jet production as a function of centrality are presented for p-Pb collisions recorded at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE detector. Centrality classes are determined via the energy deposit in neutron calorimeters at zero degree, close to the beam direction, to minimise dynamical biases of the selection. The corresponding number of participants or binary nucleon-nucleon collisions is determined based on the particle production in the Pb-going rapidity region. Jets have been reconstructed in the central rapidity region from charged particles with the anti-$k_{\rm T}$ algorithm for resolution parameters $R = 0.2$ and $R = 0.4$ in the transverse momentum range 20 to 120 GeV/$c$. The reconstructed jet momentum and yields have been corrected for detector effects and underlying-event background. In the five centrality bins considered, the charged jet production in p-Pb collisions is consistent with the production expected from binary scaling from pp collisions. The ratio of jet yields reconstructed with the two different resolution parameters is also independent of the centrality selection, demonstrating the absence of major modifications of the radial jet structure in the reported centrality classes.
pp reference spectrum, obtained by scaling down the measured charged jets at 7 TeV to 5.02 TeV for R = 0.2 jets.
$p_{\rm T}$-differential production cross section of charged jets in p-Pb collisions at 5.02 TeV for R = 0.2 measured with the ALICE detector, centrality 0-20%.
$p_{\rm T}$-differential production cross section of charged jets in p-Pb collisions at 5.02 TeV for R = 0.2 measured with the ALICE detector, centrality 20-40%.
The double-differential inclusive jet cross section is measured as a function of jet transverse momentum pT and absolute rapidity y, using proton-proton collision data collected with the CMS experiment at the LHC, at a center-of-mass energy of sqrt(s) = 2.76 TeV and corresponding to an integrated luminosity of 5.43 inverse picoboarns. Jets are reconstructed within the pT range of 74 to 592 GeV and the rapidity range |y| < 3.0. The reconstructed jet spectrum is corrected for detector resolution. The measurements are compared to the theoretical prediction at next-to-leading-order QCD using different sets of parton distribution functions. This inclusive cross section measurement explores a new kinematic region and is consistent with QCD predictions.
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The inclusive jet cross-section is measured in proton-proton collisions at a centre-of-mass energy of 7 TeV using a data set corresponding to an integrated luminosity of 4.5 fb$^{-1}$ collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-$k_t$ algorithm with radius parameter values of 0.4 and 0.6. The double-differential cross-sections are presented as a function of the jet transverse momentum and the jet rapidity, covering jet transverse momenta from 100 GeV to 2 TeV. Next-to-leading-order QCD calculations corrected for non-perturbative effects and electroweak effects, as well as Monte Carlo simulations with next-to-leading-order matrix elements interfaced to parton showering, are compared to the measured cross-sections. A quantitative comparison of the measured cross-sections to the QCD calculations using several sets of parton distribution functions is performed.
Measured double-differential inclusive-jet cross section for the range 0.0 <= |y| < 0.5 and for anti-kT jets with radius parameter R = 0.4. It is based on the data sample of proton-proton collisions at 7 TeV of centre-of-mass energy collected in 2011 by the ATLAS experiment at the LHC. The data sample corresponds to the integrated luminosity of 4.5 fb^-1. The statistical uncertainties arising from data and MC simulation have been combined. All the components of the systematic uncertainty are shown. They are: all the components of the jet energy scale uncertainty (jesX), the uncertainty of the jet energy resolution (jer), the uncertainty of the jet angular resolution (jar), the uncertainty of data unfolding (unfold), the uncertainty of the jet quality selection (qual), the luminosity uncertainty (lumi). All the components are assumed to be independent of each other. Each component is assumed to be fully correlated in pT and eta. Concerning the shape of the different components, Gaussian distribution assumption works for most of them. The three columns correspond to three different sets of the systematic uncertainty built with nominal, stronger or weaker assumptions on correlations between the jet energy scale uncertainty components. For more information on the systematic uncertainties, see the reference paper.
Measured double-differential inclusive-jet cross section for the range 0.5 <= |y| < 1.0 and for anti-kT jets with radius parameter R = 0.4. It is based on the data sample of proton-proton collisions at 7 TeV of centre-of-mass energy collected in 2011 by the ATLAS experiment at the LHC. The data sample corresponds to the integrated luminosity of 4.5 fb^-1. The statistical uncertainties arising from data and MC simulation have been combined. All the components of the systematic uncertainty are shown. They are: all the components of the jet energy scale uncertainty (jesX), the uncertainty of the jet energy resolution (jer), the uncertainty of the jet angular resolution (jar), the uncertainty of data unfolding (unfold), the uncertainty of the jet quality selection (qual), the luminosity uncertainty (lumi). All the components are assumed to be independent of each other. Each component is assumed to be fully correlated in pT and eta. Concerning the shape of the different components, Gaussian distribution assumption works for most of them. The three columns correspond to three different sets of the systematic uncertainty built with nominal, stronger or weaker assumptions on correlations between the jet energy scale uncertainty components. For more information on the systematic uncertainties, see the reference paper.
Measured double-differential inclusive-jet cross section for the range 1.0 <= |y| < 1.5 and for anti-kT jets with radius parameter R = 0.4. It is based on the data sample of proton-proton collisions at 7 TeV of centre-of-mass energy collected in 2011 by the ATLAS experiment at the LHC. The data sample corresponds to the integrated luminosity of 4.5 fb^-1. The statistical uncertainties arising from data and MC simulation have been combined. All the components of the systematic uncertainty are shown. They are: all the components of the jet energy scale uncertainty (jesX), the uncertainty of the jet energy resolution (jer), the uncertainty of the jet angular resolution (jar), the uncertainty of data unfolding (unfold), the uncertainty of the jet quality selection (qual), the luminosity uncertainty (lumi). All the components are assumed to be independent of each other. Each component is assumed to be fully correlated in pT and eta. Concerning the shape of the different components, Gaussian distribution assumption works for most of them. The three columns correspond to three different sets of the systematic uncertainty built with nominal, stronger or weaker assumptions on correlations between the jet energy scale uncertainty components. For more information on the systematic uncertainties, see the reference paper.
Charged jet production cross sections in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV measured with the ALICE detector at the LHC are presented. Using the anti-$k_{\rm T}$ algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters $R = 0.2$ and $R = 0.4$. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, $R_{\rm pPb}$, of charged jets in p-Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at $\sqrt{s} = 7$ TeV. In the transverse momentum range $20 \le p_{\rm T,ch\ jet} \le 120$ GeV/$c$, $R_{\rm pPb}$ is found to be consistent with unity, indicating the absence of strong nuclear matter effects on jet production. Major modifications to the radial jet structure are probed via the ratio of jet production cross sections reconstructed with the two different resolution parameters. This ratio is found to be similar to the measurement in pp collisions at $\sqrt{s} = 7$ TeV and to the expectations from PYTHIA pp simulations and NLO pQCD calculations at $\sqrt{s_{\rm NN}} = 5.02$ TeV.
$p_\mathrm{T}$-differential production cross section of charged jets in p-Pb collisions at 5.02 TeV for $R = 0.2$ measured with the ALICE detector.
$p_\mathrm{T}$-differential production cross section of charged jets in p-Pb collisions at 5.02 TeV for R = 0.2 calculated with a Lorentz-boosted NLO pQCD calculation using POWHEG+PYTHIA8 with CTEQ6.6+EPS09.
$p_\mathrm{T}$-differential production cross section of charged jets in p-Pb collisions at 5.02 TeV for R = 0.2 measured with the ALICE detector. Eta-Interval 0.25 < $\eta$ < 0.65.
The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at centre-of-mass energy $\sqrt{s}=7$ TeV using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the mid-rapidity region using the sequential recombination $k_{\rm T}$ and anti-$k_{\rm T}$ as well as the SISCone jet finding algorithms with several resolution parameters in the range $R=0.2$ to $0.6$. Differential jet production cross sections measured with the three jet finders are in agreement in the transverse momentum ($p_{\rm T}$) interval $20<p_{\rm T}^{\rm jet,ch}<100$ GeV/$c$. They are also consistent with prior measurements carried out at the LHC by the ATLAS collaboration. The jet charged particle multiplicity rises monotonically with increasing jet $p_{\rm T}$, in qualitative agreement with prior observations at lower energies. The transverse profiles of leading jets are investigated using radial momentum density distributions as well as distributions of the average radius containing 80% ($\langle R_{\rm 80} \rangle$) of the reconstructed jet $p_{\rm T}$. The fragmentation of leading jets with $R=0.4$ using scaled $p_{\rm T}$ spectra of the jet constituents is studied. The measurements are compared to model calculations from event generators (PYTHIA, PHOJET, HERWIG). The measured radial density distributions and $\langle R_{\rm 80} \rangle$ distributions are well described by the PYTHIA model (tune Perugia-2011). The fragmentation distributions are better described by HERWIG.
Measured charged jet differential cross sections for INEL proton-proton collisions at $\sqrt{s}$ = 7 TeV.
Measured charged jet differential cross sections for INEL proton-proton collisions at $\sqrt{s}$ = 7 TeV.
Measured charged jet differential cross sections for INEL proton-proton collisions at $\sqrt{s}$ = 7 TeV.
Characteristics of multi-particle production in proton-proton collisions at $\sqrt{s}$=7 TeV are studied as a function of the charged-particle multiplicity, $N_{ch}$. The produced particles are separated into two classes: those belonging to jets and those belonging to the underlying event. Charged particles are measured with pseudorapidity |η|<2.4 and transverse momentum $p_T$ > 0.25 GeV/c. Jets are reconstructed from charged-particles only and required to have $p_T$ > 5 GeV/c. The distributions of jet $p_T$, average $p_T$ of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of $N_{ch}$ and compared to the predictions of the PYTHIA and HERWIG event generators. Predictions without multi-parton interactions fail completely to describe the $N_{ch}$-dependence observed in the data. For increasing $N_{ch}$, PYTHIA systematically predicts higher jet rates and harder $p_T$ spectra than seen in the data, whereas HERWIG shows the opposite trends. At the highest multiplicity, the data–model agreement is worse for most observables, indicating the need for further tuning and/or new model ingredients.
Mean $p_T$, all charged particles.
Mean $p_T$, UE charged particles.
Mean $p_T$, in-jet charged particles.
Measurements of the inclusive jet cross section with the anti-kt clustering algorithm are presented for two radius parameters, R=0.5 and 0.7. They are based on data from LHC proton-proton collisions at $\sqrt{s}$ = 7 TeV corresponding to an integrated luminosity of 5.0 inverse femtobarns collected with the CMS detector in 2011. The ratio of these two measurements is obtained as a function of the rapidity and transverse momentum of the jets. Significant discrepancies are found comparing the data to leading-order simulations and to fixed-order calculations at next-to-leading order, corrected for nonperturbative effects, whereas simulations with next-to-leading-order matrix elements matched to parton showers describe the data best.
Inclusive Jet cross section with R = 0.5 in the rapidity bin 0 < |y| < 0.5. The total uncorrelated uncertainty includes statistical one and systematic uncorrelated. The total systematic uncertainty includes all other sources, especially the luminosity uncertainty of 2.2%. The total error can be obtained as a quadratic sum of uncorrelated and correlated one. The NP correction can be used to scale theory prediction to compare to data at particle level.
Inclusive Jet cross section with R = 0.5 in the rapidity bin 0.5 < |y| < 1. The total uncorrelated uncertainty includes statistical one and systematic uncorrelated. The total systematic uncertainty includes all other sources, especially the luminosity uncertainty of 2.2%. The total error can be obtained as a quadratic sum of uncorrelated and correlated one. The NP correction can be used to scale theory prediction to compare to data at particle level.
Inclusive Jet cross section with R = 0.5 in the rapidity bin 1 < |y| < 1.5. The total uncorrelated uncertainty includes statistical one and systematic uncorrelated. The total systematic uncertainty includes all other sources, especially the luminosity uncertainty of 2.2%. The total error can be obtained as a quadratic sum of uncorrelated and correlated one. The NP correction can be used to scale theory prediction to compare to data at particle level.
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