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/$c$.
Diboson production in association with jets is studied in the fully leptonic final states, pp $\to$ (Z$\gamma^*$)(Z/$\gamma^*$)+jets $\to$ 2$\ell$2$\ell'$+jets, ($\ell,\ell'$ = e or $\mu$) in proton-proton collisions at a center-of-mass energy of 13 TeV. The data sample corresponds to an integrated luminosity of 138 fb$^{-1}$ collected with the CMS detector at the LHC. Differential distributions and normalized differential cross sections are measured as a function of jet multiplicity, transverse momentum $p_\mathrm{T}$, pseudorapidity $\eta$, invariant mass and $\Delta\eta$ of the highest-$p_\mathrm{T}$ and second-highest-$p_\mathrm{T}$ jets, and as a function of invariant mass of the four-lepton system for events with various jet multiplicities. These differential cross sections are compared with theoretical predictions that mostly agree with the experimental data. However, in a few regions we observe discrepancies between the predicted and measured values. Further improvement of the predictions is required to describe the ZZ+jets production in the whole phase space.
Differential cross sections normalized to the fiducial cross section as a function of the invariant mass of the four-lepton system, in the on-shell ZZ region
Differential cross sections normalized to the fiducial cross section as a function of the number of jets with $p_T > 30$ GeV
Differential cross sections normalized to the fiducial cross section as a function of the $p_T$ of the highest-$p_T$ jet
The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at sqrt(s) = 7 TeV. The full data set collected in 2011, corresponding to an integrated luminosity of 4.9 fb-1, is used. The amount of background, from hadronic jets and isolated electrons, is estimated with data-driven techniques and subtracted. The total cross section, for two isolated photons with transverse energies above 25 GeV and 22 GeV respectively, in the acceptance of the electromagnetic calorimeter (|eta|<1.37 and 1.52<|eta|<2.37) and with an angular separation Delta R>0.4, is 44.0 (+3.2) (-4.2) pb. The differential cross sections as a function of the di-photon invariant mass, transverse momentum, azimuthal separation, and cosine of the polar angle of the largest transverse energy photon in the Collins--Soper di-photon rest frame are also measured. The results are compared to the prediction of leading-order parton-shower and next-to-leading-order and next-to-next-to-leading-order parton-level generators.
The dynamics of isolated-photon plus one-, two- and three-jet production in $pp$ collisions at a centre-of-mass energy of 8 TeV are studied with the ATLAS detector at the LHC using a data set with an integrated luminosity of 20.2 fb$^{-1}$. Measurements of isolated-photon plus jets cross sections are presented as functions of the photon and jet transverse momenta. The cross sections as functions of the azimuthal angle between the photon and the jets, the azimuthal angle between the jets, the photon-jet invariant mass and the scattering angle in the photon-jet centre-of-mass system are presented. The pattern of QCD radiation around the photon and the leading jet is investigated by measuring jet production in an annular region centred on each object; enhancements are observed around the leading jet with respect to the photon in the directions towards the beams. The experimental measurements are compared to several different theoretical calculations, and overall a good description of the data is found.
Measured cross sections for isolated-photon plus 1jet production as a function of $E_{\rm T}^{\gamma}$.
Measured cross sections for isolated-photon plus 1jet production as a function of $p_{\rm T}^{\rm jet1}$.
Measured cross sections for isolated-photon plus 1jet production as a function of $m^{\gamma-\rm jet1}$.
This paper describes a measurement of fiducial and differential cross sections of gluon-fusion Higgs boson production in the $H{\rightarrow\,}WW^{\ast}{\rightarrow\,}e\nu\mu\nu$ channel, using 20.3 fb$^{-1}$ of proton-proton collision data. The data were produced at a centre-of-mass energy of $\sqrt{s} = 8$ TeV at the CERN Large Hadron Collider and recorded by the ATLAS detector in 2012. Cross sections are measured from the observed $H{\rightarrow\,}WW^{\ast}{\rightarrow\,}e\nu\mu\nu$ signal yield in categories distinguished by the number of associated jets. The total cross section is measured in a fiducial region defined by the kinematic properties of the charged leptons and neutrinos. Differential cross sections are reported as a function of the number of jets, the Higgs boson transverse momentum, the dilepton rapidity, and the transverse momentum of the leading jet. The jet-veto efficiency, or fraction of events with no jets above a given transverse momentum threshold, is also reported. All measurements are compared to QCD predictions from Monte Carlo generators and fixed-order calculations, and are in agreement with the Standard Model predictions.
Measured fiducial cross section in fb as a function of Njet. Jet PT>25 GeV for |eta|<2.4 and PT>30 GeV for 2.4<|eta|<4.5.
Measured fiducial cross section in fb/GeV as a function of pTH.
Measured fiducial cross section in fb as a function of Yll.
The production of prompt $\Lambda^+_\mathrm{c}$ baryons is measured via the exclusive decay channel $\Lambda^+_\mathrm{c}$$\to$ pK$^-\pi^+$ at a center-of-mass energy per nucleon pair of 5.02 TeV, using proton-proton (pp) and lead-lead (PbPb) collision data collected by the CMS experiment at the CERN LHC. The pp and PbPb data were obtained in 2017 and 2018 with integrated luminosities of 252 and 0.607 nb$^{-1}$, respectively. The measurements are performed within the $\Lambda^+_\mathrm{c}$ rapidity interval $\vert y \vert$$\lt$ 1 with transverse momentum ($p_\mathrm{T}$) ranges of 3-30 and 6-40 GeV/$c$ for pp and PbPb collisions, respectively. Compared to the yields in pp collisions scaled by the expected number of nucleon-nucleon interactions, the observed yields of $\Lambda^+_\mathrm{c}$ with $p_\mathrm{T}$$\gt$ 10 GeV/$c$ are strongly suppressed in PbPb collisions. The level of suppression depends significantly on the collision centrality. The $\Lambda^+_\mathrm{c}$ / D$^0$ production ratio is similar in PbPb and pp collisions at $p_\mathrm{T}$$\gt$ 10 GeV/$c$, suggesting that the coalescence process does not play a dominant role in prompt $\Lambda^+_\mathrm{c}$ baryon production at higher $p_\mathrm{T}$.
The $p_{\mathrm{T}}$ differential cross sections for prompt $\Lambda^+_c$ production in pp collisions. The global fit uncertainty is 8.6%.
The nuclear modification factor $\mathrm{R_{AA}}$ versus $p_{\mathrm{T}}$ for prompt $\Lambda^+_c$ production in centrality regions of 0-90, 0-10, 10-30, 30-50 and 50-90% in PbPb collisions. The global uncertainty includes the uncertainties for the luminosity of pp collisions, number of MB events in PbPb collisions, and tracking efficiency. The global uncertainty for $\mathrm{R_{AA}}$ is 16.5%.
The ratio of the production cross sections of prompt $\Lambda^+_c$ to prompt $\mathrm{D_0}$ versus $p_{\mathrm{T}}$ from pp collisions. The global normalization uncertainty is 6.6%.
The measurement of the cross section for the production of a Z boson, decaying to dielectrons or dimuons, in association with at least one bottom quark jet are performed with proton-proton collision data at $\sqrt{s} =$ 13 TeV. The data sample corresponds to an integrated luminosity of 137 fb$^{-1}$, collected by the CMS experiment at the LHC during 2016-2018. The integrated cross sections for Z + $\ge$ 1 b jet and Z + $\ge$ 2 b jets are reported for the electron, muon, and combined channels. The fiducial cross sections in the combined channel are 6.52 $\pm$ 0.04 (stat) $\pm$ 0.40 (syst) $\pm$ 0.14 (theo) pb for Z + $\ge$ 1 b jet and 0.65 $\pm$ 0.03 (stat) $\pm$ 0.07 (syst) $\pm$ 0.02 (theo) pb for Z + $\ge$ 2 b jets. The differential cross section distributions are measured as functions of various kinematic observables that are useful for precision tests of perturbative quantum chromodynamics predictions. The ratios of integrated and differential cross sections for Z + $\ge$ 2 b jets and Z + $\ge$ 1 b jet processes are also determined. The value of the integrated cross section ratio measured in the combined channel is 0.100 $\pm$ 0.005 (stat) $\pm$ 0.007 (syst) $\pm$ 0.003 (theo). All measurements are compared with predictions from various event generators.
Differential cross section distribution as a function of Z transverse momentum for the Z + >= 1 b jet events
Normalized differential cross section distribution as a function of Z transverse momentum for the Z + >= 1 b jet events
Differential cross section distribution as a function of the leading b jet transverse momentum for the Z +>= 1 b jet events
We present a measurement of the differential cross section as a function of transverse momentum of the Z boson in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0 experiment at the Fermilab Tevatron Collider during 1994--1996. We find good agreement between our data and the NNLO resummation prediction and extract values of the non-perturbative parameters for the resummed prediction from a fit to the differential cross section.
Differential cross section in the electron channel. The errors contain both statistical and systematic error excluding the overall normalization error.
A measurement is presented of the production of Z bosons that decay into two electrons or muons in association with jets, in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data were recorded by the CMS Collaboration at the LHC with an integrated luminosity of 35.9 fb$^{-1}$. The differential cross sections are measured as a function of the transverse momentum ($p_\mathrm{T}$) of the Z boson and the transverse momentum and rapidities of the five jets with largest $p_\mathrm{T}$. The jet multiplicity distribution is measured for up to eight jets. The hadronic activity in the events is estimated using the scalar sum of the $p_\mathrm{T}$ of all the jets. All measurements are unfolded to the stable particle-level and compared with predictions from various Monte Carlo event generators, as well as with expectations at leading and next-to-leading orders in perturbative quantum chromodynamics.
Measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$, and breakdown of the relative uncertainty.
Bin-to-bin correlation in the measured cross section as a function of exclusive jet multiplicity, $N_{\text{jets}}$.
Measured cross section as a function of the rapidity absolute value of the first jet, $|y(\text{j}_1)|$, and breakdown of the relative uncertainty.
The differential cross sections of $\Lambda_\mathrm{c}^+$ baryon production are measured via the exclusive decay channel $\Lambda_\mathrm{c}^+ \to $pK$^-\pi^+$, as a function of transverse momentum ($p_\mathrm{T}$) in proton-proton (pp) and lead-lead (PbPb) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV with the CMS detector at the LHC. The measurement is performed within the $\Lambda_\mathrm{c}^+$ rapidity interval $|y|<$1.0 in the $p_\mathrm{T}$ range of 5-20 GeV/$c$ in pp and 10-20 GeV/$c$ in PbPb collisions. The observed yields of $\Lambda_\mathrm{c}^+$ for $p_\mathrm{T}$ of 10-20 GeV/$c$ suggest a possible suppression in central PbPb collisions compared to pp collisions. The $\Lambda_\mathrm{c}^+/$D$^0$ production ratio in pp collisions is compared to theoretical models. In PbPb collisions, this ratio is consistent with the result from pp collisions in their common $p_\mathrm{T}$ range.
The $p_{T}$-differential cross sections for inclusive $\Lambda_{c}^{+}$ production in pp collisions. The uncertainties associated with the $\Lambda_{c}^{+} \to pK^{-}\pi^{+}$ branching fraction and subresonant contributions, the luminosity and the nonprompt fraction contribute only to the overall normalization and are labeled global uncertainties ($21\%$).
The nuclear modification factor $R_{AA}$ versus $\langle N_\text{part} \rangle$ for inclusive $\Lambda_{c}^{+}$ production in the centrality range $0-100\%$, $0-30\%$ and $30-100\%$. The systematic uncertainties include the PbPb systematic uncertainties associated with the signal extraction, $p_{T}$ spectrum, selection criteria, track reconstruction, and $T_{AA}$. The pp uncertainty includes the same uncertainties for the pp data (except for $T_{AA}$) plus the uncertainties in pp yield and luminosity. The global PbPb uncertainty includes the uncertainty from the nonprompt fraction(accounting for a partial cancelation between pp and PbPb) and MB selection efficiency.
The ratio of the production cross sections of inclusive $\Lambda_{c}^{+}$ to prompt $D^{0}$ versus $p_{T}$ from pp collisions. The $20\%$ normalization uncertainty in pp collisions is not included in the statistical and systematic uncertainties for each data point.
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