Herwig 7 is hosted by Hepforge, IPPP Durham

Plots from Rivet analyses

Tranverse momentum spectra of pions, kaons and protons in pp collisions at 7 TeV (ALICE_2015_I1357424)

Spires

Obtaining the transverse momentum spectra of primary pions, kaons and protons in $pp$ collisions at $\sqrt{s} = 7$ TeV with ALICE at the LHC. K/pi and p/pi ratios are also included.

Production of $\Sigma(1385)^{\pm}$ and $\Xi(1530)^{0}$ in proton-proton collisions at $\sqrt{s} =$ 7 TeV (ALICE_2014_I1300380)

Spires

Transverse momentum spectra $\frac{1}{N_{\rm inel}} \frac{{\rm d}^2N}{{\rm d}p_{\rm T}{\rm d}y}$ of $\Sigma(1385)^{\pm}$, $\overline{\Sigma}(1385)^{\pm}$ and $(\Xi(1530)^{0}+\overline{\Xi}(1530)^{0})/2$ at mid-rapidity ($|y| < 0.5$) in inelastic proton-proton collisions at $\sqrt{s} =$ 7 TeV

Measurement of inelastic, single- and double-diffraction cross sections in proton--proton collisions at the LHC with ALICE (ALICE_2012_I1181770)

Spires | arXiv:1208.4968 [hep-ex]

Measurements of cross-sections of inelastic and diffractive processes in proton-proton collisions at $\sqrt{s} = 900$, 2760 and 7000 GeV. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudorapidity distributions. Single-diffractive events are selected with $M_{X} < 200\;\text{GeV}/c^2$ and double-diffractive events defined as NSD events with $\Delta\eta > 3$. To measure the inelastic cross-section, beam properties were determined with van der Meer scans using a simulation of diffraction adjusted to data. Note that these are experimental approximations to theoretical concepts -- it is not totally clear whether the data point values are model-independent.

Tranverse momentum spectra of pions, kaons and protons in pp collisions at 0.9 TeV (ALICE_2011_S8945144)

Spires | Eur.Phys.J.C71:1655,2011. | arXiv:1101.4110 [hep-ex]

Obtaining the transverse momentum spectra of pions, kaons and protons in $pp$ collisions at $\sqrt{s} = 0.9$ TeV with ALICE at the LHC. Mean transverse momentum as a function of the mass of the emitted particle is also included.

Strange particle production in proton-proton collisions at $\sqrt{s} = 0.9$ TeV with ALICE at the LHC. (ALICE_2011_S8909580)

Spires | Eur.Phys.J.C71:1594,2011.

Tranverse momentum spectra of strange particles ($K^0_S$, $\Lambda$, $\phi$ and $\Xi$) in $pp$ collisions at $\sqrt{s} = 0.9$\;TeV with ALICE at the LHC. The ratio of cross-sections as a function of pT for $\Lambda/K^0_S$ is also included.

Charged particle $\langle p_\perp \rangle$ vs. $N_\text{ch}$ in $pp$ collisions at 900 GeV (ALICE_2010_S8706239)

Spires | Phys.Lett.B693:53-68,2010 | arXiv:1007.0719 [hep-ex]

ALICE measurement of $\langle p_\perp \rangle$ vs. $N_\text{ch}$ and invariant particle yield (as function of $p_\perp$) in proton-proton collisions at $\sqrt{s} = 900\;\text{GeV}$.

Pseudorapidities at three energies, charged multiplicity at 7 TeV. (ALICE_2010_S8625980)

Spires | Eur.Phys.J. C68 (2010) 345-354 | arXiv:1004.3514 [hep-ex]

This is an ALICE publication with pseudorapities for 0.9, 2.36 and $7\;\text{TeV}$ and the charged multiplicity at $7\;\text{TeV}$. The analysis requires at least on charged particle in the event. Only the INEL distributions are considered here

Charged particle multiplicities at 0.9 and 2.36\;TeV in three different pseudorapidity intervals. (ALICE_2010_S8624100)

Spires | Eur.Phys.J.C68:89-108,2010 | arXiv:1004.3034 [hep-ex]

This is an ALICE analysis where charged particle multiplicities (including the zero bin) have been measured in three different pseudorapidity intervals ($|\eta|<0.5; |\eta|<1.0; |\eta|<1.3$. Only the INEL distributions have been considered here, i.e. this analysis can only be meaningfully compared to PYTHIA 6 with diffractive processes disabled. The data were taken at 900 and 2360\;GeV.

Energy-energy correlation (ATLAS_2015_I1387176)

Spires | arXiv:1508.01579 [hep-ex]

High transverse momentum jets produced in $pp$ collisions at a centre-of-mass energy of 7\,TeV are used to measure the transverse energy-energy correlation function and its associated azimuthal asymmetry. The data were recorded with the ATLAS detector at the LHC in the year 2011 and correspond to an integrated luminosity of $158\,\text{pb}^{−1}$. The selection criteria demand the average transverse momentum of the two leading jets in an event to be larger than 250\,GeV. The data are unfolded to the particle level. NB--If the routine is to be run on several samples (with different cross sections), the asymmetry has to be calculated again in a post-processing step using the merged output file.

Pseudo-top-antitop cross sections (ATLAS_2015_I1345452)

Spires | arXiv:1502.05923 [hep-ex]

Various differential cross-sections are measured in top-quark pair ($t\bar{t}$) events produced in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV at the LHC with the ATLAS detector. These differential cross-sections are presented in a data set corresponding to an integrated luminosity of 4.6 fb$^{-1}$. The differential cross-sections are presented in terms of kinematic variables of a top-quark proxy referred to as the pseudo-top-quark whose dependence on theoretical models is minimal. The pseudo-top-quark can be defined in terms of either reconstructed detector objects or stable particles in an analogous way. The measurements are performed on $t\bar{t}$ events in the lepton+jets channel, requiring exactly one charged lepton and at least four jets with at least two of them tagged as originating from a $b$-quark. The hadronic and leptonic pseudo-top-quarks are defined via the leptonic or hadronic decay mode of the W boson produced by the top-quark decay in events with a single charged lepton. The cross-section is measured as a function of the transverse momentum and rapidity of both the hadronic and leptonic pseudo-top-quark as well as the transverse momentum, rapidity and invariant mass of the pseudo-top-quark pair system. The measurements are corrected for detector effects and are presented within a kinematic range that closely matches the detector acceptance.

Measurement of the inclusive jet cross-section at 7 TeV (ATLAS_2014_I1325553)

Spires | arXiv:1410.8857 [hep-ex]

Measurement of the inclusive jet cross-section 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-kt 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.

Measurements of jet vetoes and azimuthal decorrelations in dijet events produced in pp collisions at $\sqrt{s}$ = 7 TeV using the ATLAS detector (ATLAS_2014_I1307243)

Spires | EPJ C74,3117 (2014) | doi:10.1140/epjc/s10052-014-3117-7 | arXiv:hep-ex/1407.5756

Additional jet activity in dijet events is measured using $pp$ collisions at ATLAS at a centre-of-mass energy of 7 TeV, for jets reconstructed using the anti-kt algorithm with radius parameter R=0.6. This is done using variables such as the fraction of dijet events without an additional jet in the rapidity interval bounded by the dijet subsystem and correlations between the azimuthal angles of the dijets. They are presented, both with and without a veto on additional jet activity in the rapidity interval, as a function of the mean transverse momentum of the dijets and of the rapidity interval size. The double differential dijet cross section is also measured as a function of the interval size and the azimuthal angle between the dijets. These variables probe differences in the approach to resummation of large logarithms when performing QCD calculations. The data are compared to POWHEG, interfaced to the PYTHIA 8 and HERWIG parton shower generators, as well as to HEJ with and without interfacing it to the ARIADNE parton shower generator. None of the theoretical predictions agree with the data across the full phase-space considered; however, POWHEG+PYTHIA 8 and HEJ+ARIADNE are found to provide the best agreement with the data. These measurements use the full data sample collected with the ATLAS detector in 7 TeV $pp$ collisions at the LHC and correspond to integrated luminosities of 36.1 pb$^-1$ and 4.5 fb$^-1$ for data collected during 2010 and 2011 respectively.

Measurement of jet multiplicity and transverse momentum spectra in top events using full 7 TeV ATLAS dataset (ATLAS_2014_I1304688)

Spires | CERN-PH-EP-2014-114 | arXiv:1407.0891[hep-ex]

Measurement of the differential t$\bar{\mathrm t}$ production cross-section in 7 TeV proton-proton collisions in the single-lepton channel from ATLAS. The data comprise the full 2011 data sample corresponding to an integrated luminosity of $4.6\,\mathrm{fb}^{-1}$. The differential cross-sections are measured as a function of the jet multiplicity for up to eight jets using jet transverse momentum thresholds of 25, 40, 60, and 80 GeV, and as a function of jet transverse momentum up to the fifth leading jet. The results after background subtraction are corrected for all detector effects, within a kinematic range closely matched to the experimental acceptance.

Leading jet underlying event at 7 TeV in ATLAS (ATLAS_2014_I1298811)

Spires | arXiv:1406.0392 | Eur.Phys.J. C74 (2014) 2965 | DOI:10.1140/epjc/s10052-014-2965-5

Underlying event measurements with the ATLAS detector at the LHC at a center-of-mass energy of 7 TeV, using the leading jet for event azimuthal orientation and constructing standard transverse region observables from both charged tracks and calorimeter clusters.

The differential production cross section of the $\phi(1020)$ meson in $\sqrt{s}=7$ TeV $pp$ collisions measured with the ATLAS detector (ATLAS_2014_I1282441)

Spires | arXiv:1402.6162 [hep-ex]

A measurement is presented of the $\phi \rightarrow K^+K^-$ production cross section at $\sqrt{s}$ = 7 TeV using pp collision data corresponding to an integrated luminosity of 383 $\mu$b$^{-1}$ collected with the ATLAS experiment at the LHC. Selection of $\phi(1020)$ mesons is based on the identification of charged kaons by their energy loss in the pixel detector. The differential cross section is measured as a function of the transverse momentum, $pT,\phi$, and rapidity, $y_\phi$, of the $\phi(1020)$ meson in the fiducial region 500 < $pT,\phi$ < 1200 MeV, |$y_\phi$| < 0.8, kaon $pT,K$ > 230 MeV and kaon momentum $p_K$ < 800 MeV. The integrated $\phi(1020)$ production cross section in this fiducial range is measured to be $\sigma_{\phi \rightarrow K^+K^-}$ = 570 \pm 8 (stat) \pm 66 (syst) \pm 20 (lumi) $\mu$b.

High-mass dijet cross section (ATLAS_2014_I1268975)

Spires | arXiv:1312.3524 [hep-ex] | JHEP 1405 (2014) 059

Double-differential dijet cross sections measured in pp collisions at the LHC with a 7 TeV centre-of-mass energy are presented as functions of dijet mass and rapidity separation of the two highest-pT jets. These measurements are obtained using data corresponding to an integrated luminosity of 4.5/fb, recorded by the ATLAS detector in 2011. The data are corrected for detector effects so that cross sections are presented at the particle level. Cross sections are measured up to 5 TeV dijet mass using jets reconstructed with the anti-kt algorithm for values of the jet radius parameter of 0.4 and 0.6. The cross sections are compared with next-to-leading-order perturbative QCD calculations by NLOJET++ corrected to account for non-perturbative effects. Comparisons with POWHEG predictions, using a next-to-leading-order matrix element calculation interfaced to a parton-shower Monte Carlo simulation, are also shown. Electroweak effects are accounted for in both cases. The quantitative comparison of data and theoretical predictions obtained using various parameterizations of the parton distribution functions is performed using a frequentist method. An example setting a lower limit on the compositeness scale for a model of contact interactions is presented, showing that the unfolded results can be used to constrain contributions to dijet production beyond that predicted by the Standard Model.

Measurement of jet shapes in top quark pair events at $\sqrt{s} = 7$ TeV with ATLAS (ATLAS_2013_I1243871)

Spires | arXiv:1307.5749 [hep-ex]

Measurement of jet shapes in top pair events in the ATLAS 7 TeV run. b-jets are shown to have a wider energy density distribution than light-quark induced jets.

Flavour composition of dijet events at 7 TeV (ATLAS_2012_I1188891)

Spires | arXiv:1210.0441

The measurement of the flavour composition of dijet events produced in pp collisions at $\sqrt{s}=7\;\text{TeV}$ using the ATLAS detector. Six possible combinations of light, charm and bottom jets are identified in the dijet events, where the jet flavour is defined by the presence of bottom, charm or solely light flavour hadrons in the jet. The fractions of these dijet flavour states as functions of the leading jet transverse momentum in the range 40 GeV to 500 GeV and jet rapidity $|y| < 2.1$ are measured.

Pseudorapidity dependence of the total transverse energy at 7 TeV (ATLAS_2012_I1183818)

Spires | arXiv:1208.6256

The measurement of the sum of the transverse energy of particles as a function of particle pseudorapidity, eta, in proton-proton collisions at a centre-of-mass energy, $\sqrt{s} = 7\;\text{TeV}$ using the ATLAS detector at the Large Hadron Collider. The measurements are performed in the region $|\eta| < 4.8$ for two event classes: those requiring the presence of particles with a low transverse momentum and those requiring particles with a significant transverse momentum (dijet events where both jets have $E_T > 20$ GeV). In the second dataset measurements are made in the region transverse to the hard scatter.

Studies of the underlying event at 7 TeV with track-jets (ATLAS_2012_I1125575)

Spires | arXiv:1208.0563 [hep-ex]

Distributions sensitive to the underlying event are studied in events containing one or more charged particles. Jets are reconstructed using the anti-$k_t$ algorithm with radius parameter $R$ varying between 0.2 and 1.0. Distributions of the charged-particle multiplicity, the scalar sum of the transverse momentum of charged particles, and the average charged-particle pT are measured as functions of $p_\perp^\text{jet}$ in regions transverse to and opposite the leading jet for $4 \text{GeV} < p_\perp^\text{jet} < 100 \text{GeV}$. In addition, the $R$-dependence of the mean values of these observables is studied.

Measurement of charged-particle event shape variables (ATLAS_2012_I1124167)

Spires | arXiv:1207.6915 | Phys.Rev. D88 (2013) 032004 | 10.1103/PhysRevD.88.032004

The measurement of charged-particle event shape variables is presented in inclusive inelastic $pp$ collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented.

Jet shapes and jet masses (ATLAS_2012_I1119557)

Spires | Phys.Rev. D86 (2012) 072006 | doi:10.1103/PhysRevD.86.072006 | arXiv:1206.5369 [hep-ex]

Measurements are presented of the properties of high transverse momentum jets, produced in proton-proton collisions at a center-of-mass energy of $\sqrt{s} = 7$\;TeV. Jet mass, width, eccentricity, planar flow and angularity are measured for jets reconstructed using the anti-$k_t$ algorithm with distance parameters $R = 0.6$ and 1.0, with transverse momentum $pT > 300$\;GeV and pseudorapidity $|\eta| < 2$.

$b$-hadron production cross-section using decays to $D^*\mu^-X$ at $\sqrt{s} = 7$\;TeV (ATLAS_2012_I1118269)

Spires | arXiv:1206.3122 [hep-ex]

Measurement of $b$-hadron production cross section using 3.3\;pb$^{-1}$ of integrated luminosity, collected during the 2010 LHC run. The $b$-hadrons are selected by partially reconstructing $D^{*}\mu^-X$ final states using only direct semileptonic decays of $b$ to $D^*\mu^-X$. Differential cross sections as functions of $p_\perp$ and $|\eta|$.

Measurement of ttbar production with a veto on additional central jet activity (ATLAS_2012_I1094568)

Spires | arXiv:1203.5015 [hep-ex] | Eur.Phys.J. C72 (2012) 2043

A measurement of the additional jet activity in dileptonic ttbar events. The fraction of events passing a veto requirement are shown as a function the veto scale for four central rapidity intervals. Two veto definitions are used: events are vetoed if they contain an additional jet in the rapidity interval with transverse momentum above a threshold, or alternatively, if the scalar transverse momentum sum of all additional jets in the rapidity interval is above a threshold.

Jet mass and substructure of inclusive jets at 7 TeV (ATLAS_2012_I1094564)

Spires | JHEP 1205 (2012) 128 | doi:10.1007/JHEP05(2012)128 | arXiv:1203.4606 [hep-ex]

In this analysis, the assumption that the internal substructure of jets generated by QCD radiation is well understood is tested on an inclusive sample of jets recorded with the ATLAS detector in 2010, which corresponds to 35 $pb^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 7$ TeV. Jet invariant mass, $k_{t}$ splitting scales and $N$-subjettiness variables are presented for anti-$k_{t}$ $R = 1.0$ jets and Cambridge-Aachen $R = 1.2$ jets. Jet invariant-mass spectra for Cambridge-Aachen $R = 1.2$ jets after a splitting and filtering procedure are also presented.

Forward-backward and $\phi$ correlations at 900 GeV and 7 TeV (ATLAS_2012_I1093734)

Spires | JHEP 1207 (2012) 019 | doi:10.1007/JHEP07(2012)019 | arXiv:1203.3100 [hep-ex]

Using inelastic proton-proton interactions at $\sqrt{s}$ = 900 GeV and 7 TeV, recorded by the ATLAS detector at the LHC, measurements have been made of the correlations between forward and backward charged-particle multiplicities and, for the first time, between forward and backward charged-particle summed transverse momentum. In addition, jet-like structure in the events is studied by means of azimuthal distributions of charged particles relative to the charged particle with highest transverse momentum in a selected kinematic region of the event.

Azimuthal ordering of charged hadrons (ATLAS_2012_I1091481)

Spires | CERN-PH-EP-2011-197 | arXiv:1203.0419 [hep-ex]

Measurement of the ordering of charged hadrons in the azimuthal angle relative to the beam axis at the Large Hadron Collider (LHC). A spectral analysis of correlations between longitudinal and transverse components of the momentum of the charged hadrons is performed. Data were recorded with the ATLAS detector at centre-of-mass energies of $\sqrt{s} = 900\;\text{GeV}$ and $\sqrt{s} = 7\;\text{TeV}$. The correlations measured in a phase space region dominated by low-$p_\perp$ particles are not well described by conventional models of hadron production. The measured spectra show features consistent with the fragmentation of a QCD string represented by a helix-like ordered gluon chain.

Rapidity gap cross sections measured with the ATLAS detector in $pp$ collisions at $\sqrt{s} = 7$ TeV. (ATLAS_2012_I1084540)

Spires | arXiv:1201.2808 [hep-ex]

Pseudorapidity gap distributions in proton-proton collisions at $\sqrt{s} = 7$ TeV are studied using a minimum bias data sample with an integrated luminosity of 7.1 inverse microbarns. Cross sections are measured differentially in terms of $\Delta \eta_F$, the larger of the pseudorapidity regions extending to the limits of the ATLAS sensitivity, at $\eta = \pm 4.9$, in which no final state particles are produced above a transverse momentum threshold $p_\perp$ cut. The measurements span the region $0 < \Delta \eta_F < 8$ for $200 < p_T\text{ cut} < 800\;\text{MeV}$. At small $\Delta \eta_F$, the data test the reliability of hadronisation models in describing rapidity and transverse momentum fluctuations in final state particle production. The measurements at larger gap sizes are dominated by contributions from the single diffractive dissociation process ($pp \to Xp$), enhanced by double dissociation ($pp \to XY$) where the invariant mass of the lighter of the two dissociation systems satisfies $M_Y \lesssim 7\;\text{GeV}$. The resulting cross section is $\mathrm{d} \sigma / \mathrm{d} \Delta \eta_F \sim 1$ mb for $\Delta \eta_F \gtrsim 3$. The large rapidity gap data are used to constrain the value of the pomeron intercept appropriate to triple Regge models of soft diffraction. The cross section integrated over all gap sizes is compared with other LHC inelastic cross section measurements.

Inclusive jet and dijet cross sections at 7 TeV (ATLAS_2012_I1082936)

Spires | arXiv:1112.6297v2 [hep-ex] | CERN-PH-EP-2011-192

Inclusive jet and dijet cross sections have been measured in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector at the Large Hadron Collider. The cross sections were measured using jets clustered with the anti-kT algorithm with parameters R=0.4 and R=0.6. These measurements are based on the 2010 data sample, consisting of a total integrated luminosity of 37 inverse picobarns. Inclusive jet double-differential cross sections are presented as a function of jet transverse momentum, in bins of jet rapidity. Dijet double-differential cross sections are studied as a function of the dijet invariant mass, in bins of half the rapidity separation of the two leading jets. The measurements are performed in the jet rapidity range $|y|<4.4$, covering jet transverse momenta from 20 GeV to 1.5 TeV and dijet invariant masses from 70 GeV to 5 TeV. This is the successor analysis of ATLAS_2010_S8817804

$D^{*\pm}$ production in jets (ATLAS_2012_I1082009)

Spires | arXiv:1112.4432

Measurement of $D^{*\pm}$ meson production in jets from proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=7$ TeV at the LHC. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of $0.30\,\text{pb}^{-1}$ for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range $|eta| < 2.5$.

$K_S^0$ and $\Lambda$ production at 0.9 and 7 TeV with ATLAS (ATLAS_2011_I944826)

Spires | arXiv:1111.1297v2 [hep-ex] | Phys.Rev. D85 (2012) 012001

The production of $K_S$ and $\Lambda$ hadrons is studied in inelastic $pp$ collisions at $\sqrt{s} = 0.9$ and 7 TeV collected with the ATLAS detector at the LHC using a minimum-bias trigger. The observed distributions of transverse momentum, rapidity, and multiplicity are corrected to hadron level in a model-independent way within well defined phase-space regions. The distribution of the production ratio of $\bar{\Lambda}$ to $\Lambda$ baryons is also measured. The results are compared with various Monte Carlo simulation models. Although most of these models agree with data to within 15 percent in the $K_S$ distributions, substantial disagreements with data are found in the $\Lambda$ distributions of transverse momentum.

Inclusive and dijet cross-sections of $b$-jets in $pp$ collisions at $\sqrt{s} = 7$ TeV with ATLAS (ATLAS_2011_I930220)

Spires | Eur.Phys.J. C71 (2011) 1846 | arXiv:1109.6833 [hep-ex]

The inclusive and dijet production cross-sections have been measured for jets containing $b$-hadrons ($b$-jets) in proton--proton collisions at a centre-of-mass energy of $\sqrt{s} = 7$ TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb$^-1$. The $b$-jets are identified using either a lifetime-based method, where secondary decay vertices of $b$-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of $b$-hadrons inside jets. The inclusive $b$-jet cross-section is measured as a function of transverse momentum in the range $20 < pT < 400$ GeV and rapidity in the range $|y| < 2.1$. The $b\bar{b}$-dijet cross-section is measured as a function of the dijet invariant mass in the range $110 < $m_{jj}$ < 760$\;GeV, the azimuthal angle difference between the two jets and the angular variable $\chi$ in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG+Pythia6. MC@NLO+Herwig shows good agreement with the measured $b\bar{b}$-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central $b$-jets with large transverse momenta.

Measurement of electron and muon differential cross-section from heavy-flavour decays (ATLAS_2011_I926145)

Spires | CERN-PH-EP-2011-108 | arXiv:1109.0525 [hep-ex]

Measurement of inclusive electron and muon cross sections for $7 < p_\perp <26$ GeV in $|\eta| <2.0$, excluding $1.37<|\eta|<1.52$, and muon cross section for $4 < p_\perp < 100$ GeV in $|\eta| <2.50$. The $W/Z/\gamma^*$ component must be subtracted to leave the heavy flavour contribution.

Measurement of ATLAS track jet properties at 7 TeV (ATLAS_2011_I919017)

Spires | Phys.Rev.D 84 (2011) 054001 | doi:10.1103/PhysRevD.84.054001 | arXiv:1107.3311 | ATLAS-STDM-2010-14 | CERN-PH-EP-2011-110

ATLAS measurement of track jet pT, multiplicity per jet, longitudinal fragmentation, transverse momentum, radius w.r.t jet axis distributions, with jets constructed from charged tracks with $pT > 300$ MeV, using the anti-$k_T$ jet algorithm with $R = 0.4, 0.6$.

Measurement of the inelastic proton-proton cross-section at $\sqrt{s} = $7 TeV. (ATLAS_2011_I894867)

Spires | arXiv:1104.0326 [hep-ex]

Inelastic cross-section is measured for $\xi > 5 \times 10^{-6}$, where $\xi=M_X^2/s$ is calculated from the invariant mass, $M_X$, of hadrons selected using the largest rapidity gap in the event.

Measurement of multi-jet cross sections (ATLAS_2011_S9128077)

Spires | arXiv:1107.2092

Inclusive multi-jet production is studied using an integrated luminosity of 2.4 pb-1. Results on multi-jet cross sections are presented differential in pT of the four leading jets, HT. Additionally three-to-two jet fractions are presented differential in different observables. Jets are anti-kt with $R=0.4$ and $R=0.6$, $p_\perp>80(60)$ GeV and $|\eta|<2.8$.

Measurement of dijet production with a veto on additional central jet activity (ATLAS_2011_S9126244)

Spires | arXiv:1107.1641 [hep-ex]

A measurement of the jet activity in rapidity intervals bounded by a dijet system. The fraction of events passing a veto requirement are shown as a function of both the rapidity interval size and the average transverse momentum of the dijet system. The average number of jets above the veto threshold are also shown as a function of the same variables. There are two possible selection criteria applied to data. Either the two highest transverse momentum jets or the jets most forward and backward in rapidity are taken to define the dijet system, where the veto threhsold is 20\;GeV. Additionally for the latter selection an alternative veto transverse momentum threshold which is equal to the average transverse momentum is applied. Jet selections are based on the anti-$k_t$ algorithm with $R=0.6$, $p_\perp > 20$\;GeV and $|y_\text{jet}| < 4.4$.

Measurement of J/Psi production (ATLAS_2011_S9035664)

Spires | ~ | arXiv:1104.3038 [hep-ex]

The inclusive $J/\psi$ production cross-section and fraction of $J/\psi$ mesons produced in B-hadron decays are measured in proton-proton collisions at $\sqrt{s} = 7$ TeV with the ATLAS detector at the LHC, as a function of the transverse momentum and rapidity of the J/psi, using 2.3$\textrm{pb}^{-1}$ of integrated luminosity. The cross section is measured from a minimum $p_T$ of 1 GeV to a maximum of 70 GeV and for rapidities within $|y| < 2.4$ giving the widest reach of any measurement of $J/\psi$ production to date.

Calo-based underlying event at 900 GeV and 7 TeV in ATLAS (ATLAS_2011_S8994773)

Spires | arXiv:1103.1816

Underlying event measurements with the ATLAS detector at the LHC at center-of-mass energies of 900 GeV and 7 TeV, using calorimeter clusters rather than charged tracks.

Dijet azimuthal decorrelations (ATLAS_2011_S8971293)

Spires | arXiv:1102.2696

Dijet azimuthal decorrelation measured by ATLAS at 7 TeV. Jets are anti-$k_t$ with $R = 0.6$, $p_\perp > 100$\;GeV, $|\eta| < 0.8$. The analysis is binned in leading jet $p_\perp$ bins. All data is fully corrected for detector effects.

Jet shapes at 7 TeV in ATLAS (ATLAS_2011_S8924791)

Spires | arXiv:1101.0070

Measurement of jet shapes in inclusive jet production in $pp$ collisions at 7 TeV based on 3 pb$^{-1}$ of data. Jets are reconstructed in $|\eta| < 5$ using the anti-$k_\perp$ algorithm with $30 < p_\perp < 600$ GeV and $|y| < 2.8$.

Cross-section of and fragmentation function in anti-kt track jets (ATLAS_2010_CONF_2010_049)

Spires | ATLAS-CONF-2010-049

Jets are identified and their properties studied using tracks measured by the ATLAS Inner Detector. Events are selected using a minimum-bias trigger, allowing the emergence of jets at low transverse momentum to be observed and for jets to be studied independently of the calorimeter. Jets are reconstructed using the anti-kt algorithm applied to tracks with two parameter choices, 0.4 and 0.6. An inclusive jet transverse momentum cross section measurement from 4 GeV to 80 GeV is shown, integrated over $|\eta| < 0.57$ and corrected to charged particle-level truth jets. The probability that a particular particle carries a fixed fraction of the jet momentum (fragmentation function) is also measured. All data is corrected to the particle level. ATTENTION - Data read from plots!

Track-based minimum bias at 900 GeV and 2.36 and 7 TeV in ATLAS (ATLAS_2010_S8918562)

Spires | arXiv:1012.5104

Measurements from proton-proton collisions at centre-of-mass energies of $\sqrt{s} = 0.9$, 2.36, and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase-space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections.

Track-based underlying event at 900 GeV and 7 TeV in ATLAS (ATLAS_2010_S8894728)

Spires | arXiv:1012.0791

The underlying event measurements with the ATLAS detector at the LHC at the center of mass energies of 900 GeV and 7 TeV. The observables sensitive to the underlying event, i.e the charged particle density and charged pT sum, as well as their standard deviations and the average pT, are measured as functions of the leading track. A track pT cut of 500 MeV is applied for most observables, but the main profile plots are also shown for a lower track cut of 100 MeV, which includes much more of the soft cross-section. The angular distribution of the charged tracks with respect to the leading track is also studied, as are the correlation between mean transverse momentum and charged particle multiplicity, and the `plateau' height as a function of the leading track $|\eta|$.

Inclusive jet cross section and di-jet mass and chi spectra at 7 TeV in ATLAS (ATLAS_2010_S8817804)

Spires | arXiv:1009.5908

The first jet cross section measurement made with the ATLAS detector at the LHC. Anti-kt jets with $R=0.4$ and $R=0.6$ are resconstructed within $|y|<2.8$ and above 60 GeV for the inclusive jet cross section plots. For the di-jet plots the second jet must have pT>30 GeV. Jet pT and di-jet mass spectra are plotted in bins of rapidity between $|y| = $ 0.3, 0.8, 1.2, 2.1, and 2.8. Di-jet $\chi$ spectra are plotted in bins of di-jet mass between 340 GeV, 520 GeV, 800 GeV and 1200 GeV.

Charged particles at 900 GeV in ATLAS (ATLAS_2010_S8591806)

Spires | arXiv:1003.3124

The first measurements with the ATLAS detector at the LHC. Data were collected using a minimum-bias trigger in December 2009 during proton-proton collisions at a centre of mass energy of 900 GeV. The charged- particle density, its dependence on transverse momentum and pseudorapid- ity, and the relationship between transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range $|\eta| < 2.5$ and $p_\perp > 500$ MeV. All data is corrected to the particle level.

Underlying event measurement with leading jets at $\sqrt{s} = 2.76$ \text{TeV} (CMS_2015_I1385107)

Spires

A measurement of the underlying event (UE) activity in proton-proton collisions is performed using events with charged-particle jets produced in the central pseudorapidity region ($|\eta|^\text{jet} < 2$) and with transverse momentum $1 \leq p_T^\text{jet} < 100$ \text{GeV}. The analysis uses a data sample collected at a centre-of-mass energy of 2.76 \text{TeV} with the CMS experiment at the LHC. The UE activity is measured as a function of $p_T^\text{jet}$ in terms of the average multiplicity and scalar sum of transverse momenta of charged particles, with $|\eta| < 2$ and $p_T > 0.5$ \text{GeV}, in the azimuthal region transverse to the highest-$p_T$ jet direction. By further dividing the transverse region into two regions of smaller and larger activity, various components of the UE activity are separated.

Pseudorapidity distribution of charged hadrons in proton--proton collisions at $\sqrt{s} = 13$ TeV (CMS_2015_I1384119)

Spires | arXiv:hep-ex/1507.05915

The pseudorapidity distribution of charged hadrons in $pp$ collisions at $\sqrt{s} =13$ TeV is measured using a data sample obtained with the CMS detector, operated at zero magnetic field, at the CERN LHC. The yield of primary charged long-lived hadrons produced in inelastic $pp$ collisions is determined in the central region of the CMS pixel detector ($|eta| < 2$) using both hit pairs and reconstructed tracks.

Ratios of jet pT spectra, which relate to the ratios of inclusive, differential jet cross sections (CMS_2014_I1298810)

Spires | arXiv:1406.0324 | CMS-SMP-13-002 | CERN-PH-EP-2014-068 | Accepted by Phys. Rev. D

Ratios of jet transverse momentum spectra. The jets objects are defined using the anti-$k_{\text{T}}$ algorithm with radii of R = 0.5 and R = 0.7. The ratios are given for six 0.5 wide rapidity regions ranging from 0.0 to 3.0 and relate the ratio of inclusive, differential jet cross sections.

Studies of 4-jet production in proton-proton collisions at $\sqrt{s} = 7$ TeV (CMS_2013_I1273574)

Spires | CMS-FSQ-12-013 | CERN-PH-EP-2013-229 | arXiv:1312.6440 | Submitted to Phys. Rev. D

Measurements are presented of exclusive 4-jet production cross sections as a function of the transverse momentum $p_T$, pseudorapidity $\eta$, as well as of correlations in azimuthal angle and $p_T$ balance among the jets. The data sample was collected at a centre-of-mass energy of 7 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 36 pb$^{-1}$. The jets are reconstructed with the anti-$k_T$ jet algorithm in a range of $|\eta|<4.7$.

Probing color coherence effects in $pp$ collisions at $\sqrt{s} = 7$ TeV (CMS_2013_I1265659)

Spires | CMS-SMP-12-010 | CERN-PH-EP-2013-200 | arXiv:1311.5815

A study of color coherence effects in $pp$ collisions at a center-of-mass energy of 7 TeV is presented. The data used in the analysis were collected in 2010 with the CMS detector at the LHC and correspond to an integrated luminosity of 36/pb. Events are selected that contain at least three jets and where the two jets with the largest transverse momentum exhibit a back-to-back topology. The measured angular correlation between the second- and third-leading jet is shown to be sensitive to color coherence effects, and is compared to the predictions of Monte Carlo models with various implementations of color coherence. None of the models describe the data satisfactorily.

Jet and underlying event properties as a function of particle multiplicity (CMS_2013_I1261026)

Spires | Eur.Phys.J. C73 (2013) 2674 | arXiv:1310.4554 | CMS-FSQ-12-022, | CERN-PH-EP-2013-195

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 $|\eta| < 2.4$ and transverse momentum $p_T > 0.25$ GeV. Jets are reconstructed from charged-particles only and required to have $\pt > 5$ GeV. The distributions of jet \pt, average \pt of charged particles belonging to the underlying event or to jets, jet rates, and jet shapes are presented as functions of $N_{ch}$.

CMS jet mass measurement in dijet events (CMS_2013_I1224539_DIJET)

Spires | arXiv:1303.4811

Measurements of the mass spectra of the jets in dijet and $W/Z$+jet events from proton--proton collisions at a centre-of-mass energy of 7 TeV using a data sample of integrated luminosity of 5 fb$^-1$. The jets are reconstructed using the both the anti-$k_T$ algorithm with $R=0.7$ (AK7) and the Cambridge-Aachen algorithm with $R=0.8$ (CA8) and $R=1.2$ (CA12) with several grooming techniques applied (ungroomed, filtered, pruned and trimmed). See the text of the paper for more details. For the dijet events the distributions are presented as a function of the mean mass of the two leading jets in bins of the mean p_\perp of the two jets.

Study of the underlying event at forward rapidity in proton--proton collisions at the LHC (CMS_2013_I1218372)

Spires | JHEP 1304 (2013) 072 | 10.1007/JHEP04(2013)072 | CMS-FWD-11-003 | arXiv:1302.2394

Ratio of the energy deposited in the pseudorapidity range $-6.6 < \eta < -5.2$ for events with a charged particle jet with $|\eta|<2$ with respect to the energy in inclusive events, as a function of charged particle jet transverse momentum for $\sqrt{s}=$0.9, 2.76 and 7 TeV.

Jet-pT and dijet mass at sqrt(s) = 7 TeV (CMS_2013_I1208923)

Spires

The single jet differential cross section has been measured as a function of the jet momentum and the dijet differential cross section as a function of the dijet mass. The data has been recorded by the CMS detector at the center of mass energy of 7 TeV. To reconstruct the jets, the anti-$k_T$ algorithm with a cone radius of $R = 0.7$ (AK7) has been used. The results are split into five rapditiy bins, ranging from 0.0 to 2.5 with a width of 0.5 each.

Measurement of the inelastic proton-proton cross section at $\sqrt{s} = 7$ TeV (CMS_2012_I1193338)

Spires | arXiv:1210.6718 [hep-ex]

The inelastic cross-section is measured through two independent methods based on information from (i) forward calorimetry (for pseudorapidity $3 < |\eta| < 5$), in collisions where at least one proton loses more than $\xi > 5 \cdot 10^{-6}$ of its longitudinal momentum, and (ii) the central tracker ($|\eta| < 2.4$), in collisions containing an interaction vertex with more than 1, 2, or 3 tracks with $p_\perp > 200\;\text{MeV}/c$.

Measurement of the differential cross section for inclusive dijet production as a function of $\xi$ in 7 TeV proton-proton collisions. (CMS_2012_I1184941)

Spires | arXiv:1209.1805 [hep-ex] | Submitted to Phys. Rev. D

Measurement of the differential cross section for inclusive dijet production as a function of $\xi$ which approximates the fractional momentum loss of the scattered proton in single-diffraction events. The data used has a total integrated luminosity of 2.7 nb$^{-1}$ collected during 2010 with low instantaneous luminosity. Events are selected with at least two jets in $|\eta| < 4.4$ with $p_\perp > 20$ GeV and all final states particles are used for the reconstruction of $\xi$.

Measurement of inclusive and exclusive dijet production ratio at large rapidity intervals at center-of-mass energy 7 TeV. (CMS_2012_I1102908)

Spires | CMS-FWD-10-014 | CERN-PH-EP-2012-088 | arXiv:1204.0696 [hep-ex] | Submitted to the EPJ C

This is a measurement of the ratio of inclusive to exclusive dijet production as a function of the absolute distance in rapidity, $\Delta y$, between jets. The ratio of the Mueller-Navelet to exclusive dijet production is also measured. These measurements were performed with the CMS detector in proton-proton collisions at $\sqrt{s} = 7$ TeV for jets with $p_T > 35$ GeV and $|y| < 4.7$ taken from a mixture of two data samples, one of which containing dijets with moderate rapidity separation and the other containing dijets with large rapidity separation, with integrated luminosity of 33/nb and 5/pb respectively. The measured observables are corrected for detector effects.

Dijet angular distributions in $pp$ collisions at $\sqrt{s} = 7$ TeV (CMS_2012_I1090423)

Spires | JHEP 05 (2012) 055 | doi:10.1007/JHEP05(2012)055 | arXiv:hep-ex/1202.5535

Measurement of dijet angular distributions in proton-proton collisions at a center-of-mass energy of 7 TeV. The data sample has a total integrated luminosity of 2.2 inverse femtobarns, recorded by the CMS experiment at the LHC. Normalized dijet angular distributions have been measured for dijet invariant masses from 0.4 TeV to above 3 TeV.

Measurement of forward and forward+central jets at $\sqrt{s} = 7$ TeV (CMS_2012_I1087342)

Spires | JHEP 1206 (2012) 036 | CMS-FWD-11-002 | CERN-PH-EP-2011-179 | doi 10.1007/JHEP06(2012)036 | arXiv:1202.0704 [hep-ex]

Inclusive forward jets and forward+central jets measured by CMS at $\sqrt{s} = 7$ TeV.

Strange particle production in underlying events in proton--proton collisions at $\sqrt{s} = 7$ TeV (CMS_2012_PAS_QCD_11_010)

CMS-PAS-QCD-11-010 | http://cdsweb.cern.ch/record/1463352

Measurements of the production of $K^0_S$, $\Lambda$ and $\bar{\Lambda}$ particles in the underlying activity of events with a $p_\perp$ scale ranging from 1 to 50 GeV/$c$ in $pp$ collisions at $\sqrt{s} = 7$\;TeV.

Forward energy flow in MB and dijet events at 0.9 and 7 TeV (CMS_2011_S9215166)

Spires | JHEP 1111 148 | doi:10.1007/JHEP11(2011)148 | arXiv:hep-ex/1110.0211

Forward energy flow measured by CMS at $\sqrt{s} = 0.9$ and 7 TeV in MB and dijet events.

Traditional leading jet UE measurement at $\sqrt{s} = 0.9$ and 7 TeV (CMS_2011_S9120041)

Spires | J. High Energy Phys 09 (2011) 109

A measurement of the underlying activity in scattering processes with a hard scale in the several-GeV region is performed in proton-proton collisions at Energies of 0.9 and 7\;TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |eta| < 2 and transverse momentum $p_\perp > 0.5$\;GeV/$c$ is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. Various comparisons are made between the two different energies and also beteen two sets of cuts on p_\perp for leading track jet p_\perp-leading $> 3$\;GeV and pT-leading $> 20$\;GeV. The activity is studied using 5 types of plots. Two profile plots for the multiplicity of charged particles and the scalar sum of p_\perp. and three distributions for the two previous quantities as well as p_\perp for all the particles in the transverse region.

Measurement of ratio of the 3-jet over 2-jet cross section in $pp$ collisions at $\sqrt{s} = 7$ TeV (CMS_2011_S9088458)

Spires | Phys. Lett. B 702 (2011) 336

A measurement of the ratio of the inclusive 3-jet to 2-jet cross sections as a function of the total jet transverse momentum, $H_T$, in the range $0.2 < H_T < 2.5$ TeV is presented. The data have been collected at a proton--proton centre-of-mass energy of 7\;TeV with the CMS detector at the LHC, and correspond to an integrated luminosity of 36/pb. Jets are anti-$k_t$ with $R = 0.5$, $p_\perp > 50\;\text{GeV}$ and $|\eta| < 2.5$.

Measurement of the inclusive jet cross-section in $pp$ collisions at $\sqrt{s} = 7$ TeV (CMS_2011_S9086218)

Spires | http://cdsweb.cern.ch/record/1355680

The inclusive jet cross section is measured in pp collisions with a center-of-mass energy of 7 TeV at the LHC using the CMS experiment. The data sample corresponds to an integrated luminosity of 34 inverse picobarns. The measurement is made for jet transverse momenta in the range 18-1100 GeV and for absolute values of rapidity less than 3. Jets are anti-kt with $R=0.5$, $p_\perp>18$ GeV and $|y|<3.0$.

$K_s$, $\Lambda$, and Cascade$-$ transverse momentum and rapidity spectra at 900 and 7000 GeV. (CMS_2011_S8978280)

Spires | JHEP 05 (2011) 064 | doi:10.1007/JHEP05(2011)064 | arXiv:1102.4282 [hep-ex]

The spectra of $K_S$, $\Lambda$, and Cascade- particles were measured versus transverse-momentum ($p_\perp$) and rapidity ($y$) in proton-proton collisions at center-of-mass energies 900 and 7000 GeV. The production is normalized to all non-single-diffractive (NSD) events using corrections for trigger and selection efficiency, acceptance, and branching ratios. The results cover a rapidity range of $|y| < 2$ and a $p_\perp$ range from 0 to 10 GeV ($K_S$ and $\Lambda$) and 0 to 6 GeV (Cascade-). Antiparticles are included in all measurements so only the sums of $\Lambda$ and $\bar{\Lambda}$, and Cascade$-$ and anti-Cascade$-$ are given. The rapidity distributions are shown versus $|y|$ but normalized to a unit of $y$. Ratios of $\Lambda$/$K_S$ and Cascade$-$/$\Lambda$ production versus $p_\perp$ and $|y|$ are also given, with somewhat smaller systematic uncertainties than obtained from taking the ratio of the individual distributions.' The data were corrected according to the SD/DD/ND content of the CMS trigger, as predicted by PYTHIA6. The uncertainties connected with correct or uncorrect modelling of diffraction were included in the systematic errors.

$B/\bar{B}$ angular correlations based on secondary vertex reconstruction in $pp$ collisions (CMS_2011_S8973270)

Spires | JHEP 1103 136 | doi:10.1007/JHEP03(2011)136 | arXiv:hep-ex/1102.3194

The differential $B\bar{B}$ cross-section is measured as a function of the opening angle $\Delta{R}$ and $\Delta\phi$ using data collected with the CMS detector during 2010 and corresponding to an integrated luminosity of 3.1 pb$^{-1}$. The measurement is performed for three different event energy scales, characterized by the transverse momentum of the leading jet in the event (above 56 GeV, above 84 GeV and above 120 GeV). Simulated events are normalised in the region $\Delta{R} > 2.4$ and $\Delta\phi > 3/4\pi$ respectively.

Event shapes (CMS_2011_S8957746)

Spires | Phys.Lett.B699:48-67,2011 | arXiv:1102.0068

Central transverse Thrust and Minor have been measured in proton-proton collisions at $\sqrt{s} = 7$ TeV, with a data sample collected with the CMS detector at the LHC. The sample corresponds to an integrated luminosity of 3.2 inverse picobarns. Input for the variables are anti-$k_t$ jets with $R = 0.5$.

Dijet azimuthal decorrelations in $pp$ collisions at $\sqrt{s} = 7$ TeV (CMS_2011_S8950903)

Spires | Phys. Rev. Lett. 106 (2011) 122003 | arXiv:1101.5029 [hep-ex]

Measurements of dijet azimuthal decorrelations in $pp$ collisions at $\sqrt{s} = 7$ TeV using the CMS detector at the CERN LHC are presented. The analysis is based on an inclusive dijet event sample corresponding to an integrated luminosity of 2.9/pb. Jets are anti-$k_t$ with $R = 0.5$, $p_\perp > 80 (30)$ GeV and $|\eta| < 1.1$.

Production cross-sections of muons from $b$ hadron decays in $pp$ collisions (CMS_2011_S8941262)

Spires | JHEP 1103,090 | doi:10.1007/JHEP03(2011)090 | arXiv:hep-ex/1101.3512

A measurement of the $b$-hadron production cross-section in proton-proton collisions at $\sqrt{s} = 7$ TeV. The dataset, corresponding to 85 inverse nanobarns, was recorded with the CMS experiment at the LHC using a low-threshold single-muon trigger. Events are selected by the presence of a muon with transverse momentum greater than 6 GeV with respect to the beam direction and pseudorapidity less than 2.1. The transverse momentum of the muon with respect to the closest jet discriminates events containing $b$ hadrons from background. The inclusive $b$-hadron production cross section is presented as a function of muon transverse momentum and pseudorapidity.

Measurement of the NSD charged particle multiplicity at $\sqrt{s} = 0.9$, 2.36, and 7 TeV with the CMS detector. (CMS_2011_S8884919)

Spires | J. High Energy Phys. 01 (2011) 079 | doi:10.1007/JHEP01(2011)079 | arXiv:1011.5531 [hep-ex]

Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of $\sqrt{s} = 0.9$, 2.36, and 7 TeV, in five pseudorapidity ranges from $|\eta| < 0.5$ to $|\eta| < 2.4$. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7 TeV run in 2010. The average transverse momentum as a function of the multiplicity is also presented. The measurement of higher-order moments of the multiplicity distribution confirms the violation of Koba-Nielsen-Olesen scaling that has been observed at lower energies.

Charged particle transverse momentum and pseudorapidity spectra from proton-proton collisions at 7000 GeV. (CMS_2010_S8656010)

Spires | Phys.Rev.Lett.105:022002,2010 | doi:10.1103/PhysRevLett.105.022002 | arXiv:1005.3299 [hep-ex]

Charged particle spectra are measured in proton-proton collisions at center-of-mass energies 7000 GeV. The spectra are normalized to all non-single-diffractive (NSD) events using corrections for trigger and selection efficiency, acceptance, and branching ratios. There are transverse-momentum ($p_\perp$) spectra from 0.1 to 2 GeV in bins of pseudorapidity ($\eta$) and the $p_\perp$ spectrum from 0.1 to 6 GeV for $|\eta| < 2.4$. The $\eta$ spectra come from the average of three methods and cover $|\eta| < 2.5$ and are corrected to include all $p_\perp$. The data were corrected according to the SD/DD/ND content of the CMS trigger, as predicted by PYTHIA6. The uncertainties connected with correct or incorrect modelling of diffraction were included in the systematic errors.

Charged particle transverse momentum and pseudorapidity spectra from proton-proton collisions at 900 and 2360 GeV. (CMS_2010_S8547297)

Spires | JHEP 02 (2010) 041 | doi:10.1007/JHEP02(2010)041 | arXiv:1002.0621 [hep-ex]

Charged particle spectra are measured in proton-proton collisions at center-of-mass energies 900 and 2360 GeV. The spectra are normalized to all non-single-diffractive (NSD) events using corrections for trigger and selection efficiency, acceptance, and branching ratios. There are transverse-momentum (pT) spectra from 0.1 to 2 GeV in bins of pseudorapidity (eta) and pT spectra from 0.1 to 4 GeV for |eta|<2.4. The eta spectra come from the average of three methods and cover |eta|<2.5 and are corrected to include all pT. The data were corrected according to the SD/DD/ND content of the CMS trigger, as predicted by PYTHIA6. The uncertainties connected with correct or incorrect modelling of diffraction were included in the systematic errors.

Charged particle pseudorapidity distribution at $\sqrt{s}$=8 TeV (CMSTOTEM_2014_I1294140)

Spires | CERN-PH-EP-2014-063 | arXiv:1405.0722 | Submitted to EPJ C

The pseudorapidity distribution of charged particles produced in proton-proton collisions at a centre-of-mass energy of 8 TeV are measured in the ranges $|\eta| < 2.2$ and $5.3 < |\eta| < 6.4$, with the CMS and TOTEM detectors, respectively. The measurement is performed with a one-side TOTEM trigger, which is sensitive to 99\% of non-diffractive interactions and diffractive interactions with masses above 3.6 GeV, for three different event selections. An inclusive sample with the least selection bias, a sample enhanced in non-single diffractive events, and a sample enhanced in single-diffractive events were selected.

Charged particle multiplicities and densities in $pp$ collisions at $\sqrt{s} = 7$ TeV (LHCB_2014_I1281685)

Spires | Eur.Phys.J.C74:2888,2014 | doi:10.1140/epjc/s10052-014-2888-1 | arXiv:1402.4430 [hep-ex]

Measurement of prompt charged particle production in proton-proton collsions at a centre-of-mass energy of 7 TeV at the LHC. The measurement is performed in the kinematic range $p > 2$ GeV/$c$, $p_\perp > 0.2$ GeV/$c$ and $2.0 < \eta < 4.8$. At least one prompt charged particle per event is required. A prompt particle is defined as a particle, that either originates directly from the primary vertex or from a decay chain in which the sum of mean lifetimes does not exceed 10 ps. Charged particle multiplicities are measured in the full kinematic range as well as in regions of pseudorapidity and transverse momentum. In addition, also mean particle densities are presented as functions of pseudorapidity and transverse momentum.

Charm hadron differential cross-sections in p_\perp and rapidity (LHCB_2013_I1218996)

Spires | Nucl.Phys. B871 (2013) 1-20 | doi:10.1016/j.nuclphysb.2013.02.010 | arXiv:1302.2864 [hep-ex] | LHCB-PAPER-2012-041, CERN-PH-EP-2013-009

Measurements of differential production cross-sections with respect to transverse momentum, $d \sigma(H_c + \mathrm{c.c.}) / d p_T$, for charm hadron species $H_c \in \{ D^0, D^+, D^\ast(2010)^+, D_s^+, \Lambda_c^+ \}$ in proton--proton collisions at center-of-mass energy $\sqrt{s}= 7$ TeV. The differential cross-sections are measured in bins of hadron transverse momentum ($p_T$) and rapidity ($y$) with respect to the beam axis in the region $0 < p_T < 8$ GeV/$c$ and $2.0 < y < 4.5$, where $p_T$ and $y$ are measured in the proton--proton CM frame. In this analysis code, it is assumed that the event coordinate system is in the proton--proton CM frame with the $z$-axis corresponding to the proton--proton collision axis (as usual). Contributions of charm hadrons from the decays of $b$-hadrons and other particles with comparably large mean lifetimes have been removed in the measurement. In this analysis code, this is implemented by counting only charm hadrons that do not have an ancestor that contains a $b$ quark.

LHCb measurement of energy flow from $pp$ collisions at $\sqrt{s} = 7$ TeV (LHCB_2013_I1208105)

Spires | arXiv:1212.4755 [hep-ex] | Eur. Phys. J. C 73 (2012) 2421

The energy flow created in $pp$ collisions at 7 TeV within the fiducial pseudorapidity range of the LHCb detector ($1.9 < \eta < 4.9$) is measured for inclusive minimum bias interactions, hard scattering processes and events with enhanced or suppressed diffractive contribution. Plots for these four event classes are shown separately for all and charged only final state particles, respectively. The total energy flow is measured by combining the charged energy flow and a data-constrained MC estimate of the neutral component. For the two highest eta bins the data-constrained measurements of the neutral energy were extrapolated from the more central region as the LHCb electromagnetic calorimeter has no detection coverage in that phase space domain.

Measurement of prompt hadron production ratios in $pp$ collisions at $\sqrt{s} = 0.9$ and 7 TeV (LHCB_2012_I1119400)

Spires | arXiv:1206.5160 [hep-ex]

WARNING --- particle map is incomplete for determination of promptness, assume unknown particles to have a life time of 0 --- Measurement of the production ratios of prompt charged particles (protons, pions and kaons). Promptness is defined as originating from the primary interaction, either directly, or through the subsequent decay of a resonance.

Inclusive differential $\Phi$ production cross-section as a function of $p_\text{T}$ and $y$ (LHCB_2011_I919315)

Spires | Phys.Lett.B703:267-273,2011 | arXiv:1107.3935 [hep-ex]

Measurement of the inclusive differential $\Phi$ cross-section in $pp$ collisions at $\sqrt {s}=7$TeV in the rapidity range of $ 2.44 < y < 4.06$ and the $p_\text{T}$ range of 0.6 GeV/c $< p_\text{T} <$ 5.0 GeV/c.

$V^0$ production ratios in $pp$ collisions at $\sqrt{s}= 0.9$ and 7 TeV at LHCb (LHCB_2011_I917009)

Spires | JHEP08:034,2011 | arXiv:1107.0882[hep-ex] | doi:10.1007/JHEP08(2011)034

This paper presents the production ratios for $\bar{\Lambda}/\Lambda$ and $\bar{\Lambda}/K_{s}^{0}$ measured by LHCb detector in 2010 at $\sqrt{s} = 0.9$ TeV and 7 TeV as functions of the transverse momentum $p_\perp$ and the rapidity $y$ in the ranges $0.15 < p_\perp < 2.50\;\text{GeV}/c$ and $2.0 < y < 4.5$, respectively. The results for the two energies are merged and represented as a function of rapidity loss $\Delta y = y_{\mathrm{beam}} - y$.

Measurement of $\sigma(pp \to b \bar{b} X$ at $\sqrt{s} = 7$ TeV in the forward region (LHCB_2010_I867355)

Spires | arXiv:1009.2731 [hep-ex]

The average cross-section to produce $b$-flavoured or $\bar{b}$-flavoured hadrons is measured in different pseudorapidity intervals over the entire range of p_\perp, assuming the LEP (and Tevatron) fractions for fragmentation into $b$-flavoured hadrons.

LHCb differential cross section measurement of prompt $K^0_S$ production in three rapidity windows at $\sqrt{s} = 0.9$ TeV (LHCB_2010_S8758301)

Spires | Phys.Lett.B693:69-80,2010 | arXiv:1008.3105[hep-ex]

The paper presents the cross-section and double differential cross-section measurement for prompt $K^0_S$ production in pp collisions at $\sqrt{s} = 0.9\;TeV$. The data were taken during the LHCb run in December 2009 and cover a transversal momentum range from 0 to 1.6 GeV/c. The differential production cross-section is calculated for three rapidity windows $2.5 < y < 3.0$, $3.0 < y < 3.5$ and $3.5 < y < 4.0$ as well as the whole rapidity domain $2.5 < y < 4.0$.

Forward $\mathrm{d}N/\mathrm{d}\eta$ at 7\;TeV (TOTEM_2012_I1115294)

Spires | Europhys.Lett. 98 (2012) 31002 | arXiv:1205.4105 | CERN-PH-EP-2012-106 | TOTEM 2012-01

The TOTEM experiment has measured the charged particle pseudorapidity density $\mathrm{d}N_\text{ch}/\mathrm{d}\eta$ in $pp$ collisions at $\sqrt{s} = 7$\,TeV for $5.3 < |\eta| < 6.4$ in events with at least one charged particle with transverse momentum above 40\;MeV/$c$ in this pseudorapidity range.

Pseudorapidity distributions of charged particles at $\sqrt{s} = 0.9$ and 7 TeV (CMS_QCD_10_024)

CMS-PAS-QCD-10-024 | https://cdsweb.cern.ch/record/1341853?ln=en

Pseudorapidity distributions of charged particles in $pp$ collisions at $\sqrt{s} = 0.9$ and 7\;TeV with at least one central charged particle.

MC analysis for ttbar studies (MC_TTBAR)

This is a pure Monte Carlo study for semi-leptonic $t\bar{t}$ production.


Generated at Saturday, 05. December 2015 12:15PM