We present a measurement of the $W$-boson-pair production cross section in $p\bar{p}$ collisions at 1.96 TeV center-of-mass energy and the first measurement of the differential cross section as a function of jet multiplicity and leading-jet energy. The $W^{+}W^{-}$ cross section is measured in the final state comprising two charged leptons and neutrinos, where either charged lepton can be an electron or a muon. Using data collected by the CDF experiment corresponding to $9.7~\rm{fb}^{-1}$ of integrated luminosity, a total of $3027$ collision events consistent with $W^{+}W^{-}$ production are observed with an estimated background contribution of $1790\pm190$ events. The measured total cross section is $\sigma(p\bar{p} \rightarrow W^{+}W^{-}) = 14.0 \pm 0.6~(\rm{stat})^{+1.2}_{-1.0}~(\rm{syst})\pm0.8~(\rm{lumi})$ pb, consistent with the standard model prediction.
Measurements and predictions of $\sigma(p\bar{p} \rightarrow W^{+}W^{-} + \mathrm{jets})$. Values are given inclusively and differentially as functions of jet multiplicity and jet-transverse energy.
We study charged particle production in proton-antiproton collisions at 300 GeV, 900 GeV, and 1.96 TeV. We use the direction of the charged particle with the largest transverse momentum in each event to define three regions of eta-phi space; toward, away, and transverse. The average number and the average scalar pT sum of charged particles in the transverse region are sensitive to the modeling of the underlying event. The transverse region is divided into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The center-of-mass energy dependence of the various components of the event are studied in detail. The data presented here can be used to constrain and improve QCD Monte Carlo models, resulting in more precise predictions at the LHC energies of 13 and 14 TeV.
Average charged particle pT sum for charged particles with pT > 0.5 GeV and |eta| < 0.8 in the TransMIN region as defined by the leading charged particle, as a function of the transverse momentum of the leading charged-particle pTmax, at 300 GeV.
The first search for single top quark production from the exchange of an $s$-channel virtual $W$ boson using events with an imbalance in the total transverse momentum, $b$-tagged jets, and no identified leptons is presented. The full data set collected by the Collider Detector at Fermilab, corresponding to an integrated luminosity of 9.45 fb$^{-1}$ from Fermilab Tevatron proton-antiproton collisions at a center of mass energy of 1.96 TeV, is used. Assuming the electroweak production of top quarks of mass 172.5 GeV/$c^2$ in the $s$-channel, a cross section of $1.12_{-0.57}^{+0.61}$ (stat+syst) pb, with a significance of 1.9 standard deviations, is measured. This measurement is combined with a previous result obtained from events with an imbalance in total transverse momentum, $b$-tagged jets, and exactly one identified lepton, yielding a cross section of $1.36_{-0.32}^{+0.37}$ (stat+syst) pb, with a significance of 4.2 standard deviations.
The s-channel single top quark cross section measured assuming top quarks of mass 172.5 GeV. The measurement uses a sample of events with large missing transverse energy, two or three jets of which one or more are b-tagged and no detected electron or muon candidates.
The combined s-channel single top quark cross section measurement assuming top quarks of mass 172.5 GeV. The measurement uses two samples of events. The first sample includes events with large missing transverse energy, two or three jets of which one or more are b-tagged and no detected electron or muon candidates. The second sample includes events with large missing transverse energy, one isolated muon or electron and two jets, at least one of which is b-tagged.
We present a comprehensive analysis of inclusive W(\to e\nu)+n-jet (n\geq 1,2,3,4) production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Tevatron collider using a 3.7 fb^{-1} dataset collected by the D0 detector. Differential cross sections are presented as a function of the jet rapidities (y), lepton transverse momentum (p_T) and pseudorapidity (\eta), the scalar sum of the transverse energies of the W boson and all jets (H_T), leading dijet p_T and invariant mass, dijet rapidity separations for a variety of jet pairings for p_T-ordered and angular-ordered jets, dijet opening angle, dijet azimuthal angular separations for p_T-ordered and angular-ordered jets, and W boson transverse momentum. The mean number of jets in an event containing a W boson is measured as a function of H_T, and as a function of the rapidity separations between the two highest-p_T jets and between the most widely separated jets in rapidity. Finally, the probability for third-jet emission in events containing a W boson and at least two jets is studied by measuring the fraction of events in the inclusive W+2-jet sample that contain a third jet over a p_T threshold. The analysis employs a regularized singular value decomposition technique to accurately correct for detector effects and for the presence of backgrounds. The corrected data are compared to particle level next-to-leading order perturbative QCD predictions, predictions from all-order resummation approaches, and a variety of leading-order and matrix-element plus parton-shower event generators. Regions of the phase space where there is agreement or disagreement with the data are discussed for the different models tested.
Differential production cross-section, normalized to the measured inclusive W boson cross-section, as a function of W boson pT for events with one or more jets produced in association with a W boson. First uncertainty is statistical, second uncertainty is systematic.
We present measurements of the differential cross section $d\sigma/dp_{T}^{\gamma}$ for the associated production of a $c$-quark jet and an isolated photon with rapidity $|y^{\gamma}|< 1.0$ and transverse momentum $30 < p_{T}^{\gamma} < 300$ GeV. The $c$-quark jets are required to have $|y^{jet}| < 1.5$ and $p_{T}^{jet} >15$ GeV. The ratio of differential cross sections for photon+ c and photon+ b production as a function of $p_{T}^{\gamma}$ is also presented. The results are based on data corresponding to an integrated luminosity of 8.7 fb$^{-1}$ recorded with the D0 detector at the Fermilab Tevatron $p\bar{p}$ Collider at $\sqrt{s}=$1.96 TeV. The obtained results are compared to next-to-leading order perturbative QCD calculations using various parton distribution functions, to predictions based on the $k_{T}$-factorization approach, and to predictions from the Sherpa and Pythia Monte Carlo event generators.
The differential cross section as a function of PT for the production of GAMMA+ Charmed JET in PBAR P collisions at a centre of mass energy of 1.96 TeV.
Measurements of charged particle distributions, sensitive to the underlying event, have been performed with the ATLAS detector at the LHC. The measurements are based on data collected using a minimum-bias trigger to select proton-proton collisions at center-of-mass energies of 900 GeV and 7 TeV. The 'underlying event' is defined as those aspects of a hadronic interaction attributed not to the hard scattering process, but rather to the accompanying interactions of the rest of the proton. Three regions are defined in azimuthal angle with respect to the highest-pt charged particle in the event, such that the region transverse to the dominant momentum-flow is most sensitive to the underlying event. In each of these regions, distributions of the charged particle multiplicity, pt density, and average pt are measured. The data show a higher underlying event activity than that predicted by Monte Carlo models tuned to pre-LHC data.
Particle Number Density versus Lead Particle PT at centre-of-mass energy 900 GeV.
Particle Number Density versus Lead Particle PT at centre-of-mass energy 7000 GeV.
Particle PT Density versus Lead Particle PT at centre-of-mass energy 900 GeV.
Inclusive and semi-inclusive cross sections and distributions of γ's and π0's inK+p interactions at 70 GeV/c are presented. The results are compared to other experiments and to the Lund model for low-pT hadron collisions.
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With a segmented total absorption calorimeter of large acceptance, we have measured the total transverse energy spectrum for pp̄ collisions at s 1 2 = 540 GeV up to ΣE T = 130 GeV in the pseudo-rapidity range | η |< 1.5. Using two different algorithms, we have looked for localized depositions of transverse energy (jets). For ΣE T > 40 GeV , the fraction of events with two jets increases with Σ E T ; this event structure is dominant for ΣE T > 100 GeV. We measure the inclusive jet cross section up to E T (jet) = 60 GeV and the two-jets mass distribution to 120 GeV/ c 2 . The measured cross sections are compatible with the predictions of hard scattering models based on QCD.
DATA TAKEN IN 1981 WITH GLOBAL TRANSVERSE ENERGY TRIGGER.
DATA TAKEN IN 1982 WITH LOCAL TRANSVERSE ENERGY TRIGGER.
Energy, charge and strangeness flow inK+p interactions at 32 and 70 GeV/c, and π+p interactions at 32 GeV/c are studied in terms of the angular variable λ=|x|/pT. The data ondQ/dλ anddE/dλ show only a weak indication of scale breaking between 32 and 70 GeV/c. For inclusive “non-diffractive”, inclusive “diffractive” and exclusive “non-diffractive” jets, the fraction of charge in any angular region ΔΩ away from the central region is found to be proportional to the energy fraction in the same interval. The data ondQ/dE versus λ are compatible with some versions of dual-sheet models and agree also with the LUND Monte-Carlo model. The data are also compared with\(v(\bar v)p\) interactions in BEBC. In exclusive channels the average ratiodQ/dS=0.78±0.04 is consistent, in the framework of fragmentation models, with a larger probability for the fragmentation of the\(\bar s\)-valence quark than theu-valence quark in theK+-meson.
CHARGE AND ENERGY FLOWS IN NONDIFFRACTIVE PROTON-LIKE JET.
CHARGE AND ENERGY FLOWS IN NONDIFFRACTIVE PROTON-LIKE JET.
CHARGE AND ENERGY FLOWS IN NONDIFFRACTIVE KAON-LIKE JET.
The general characteristics of inelastic proton-antiproton collisions at the CERN SPS Collider are studied with the UA1 detector using magnetic and calorimetric analysis. Results are presented on charged particle multiplicities and transverse and longitudinal momenta, and on total transverse energy distributions at centre of mass energies ranging from 0.2 to 0.9 TeV.
Inclusive cross section for single charged hadrons as a function of PT for the pseudorapdity region 0.8 to 4 for centre of mass energy 900 GeV.. Data read from plot.
Inclusive cross section for single charged hadrons as a function of PT for the pseudorapdity region 4 to 8 for centre of mass energy 900 GeV.. Data read from plot.
Inclusive cross section for single charged hadrons as a function of PT for the pseudorapdity region > 8 for centre of mass energy 900 GeV.. Data read from plot.
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