We report a measurement of the differential cross section, d{\sigma}/d(cos {\theta}t), for top-quark-pair production as a function of the top-quark production angle in proton-antiproton collisions at sqrt{s} = 1.96 TeV. This measurement is performed using data collected with the CDF II detector at the Tevatron, corresponding to an integrated luminosity of 9.4/fb. We employ the Legendre polynomials to characterize the shape of the differential cross section at the parton level. The observed Legendre coefficients are in good agreement with the prediction of the next-to-leading-order standard-model calculation, with the exception of an excess linear-term coefficient, a1 = 0.40 +- 0.12, compared to the standard-model prediction of a1 = 0.15^{+0.07}_{-0.03}.
The parton-level Legendre moments for the measured angular distribution of the momentum direction of the t-quark from the momentum direction of the incoming proton.
We report on a measurement of the cross section for direct-photon production in association with a heavy quark using the full data set of $\sqrt{s}=1.96$ TeV proton-antiproton collisions corresponding to 9.1 fb$^{-1}$ of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron. The measurements are performed as a function of the photon transverse momentum, covering photon transverse momentum between 30 and 300 GeV, photon rapidities $|y^{\gamma}|<1.0$, heavy-quark-jet transverse momentum $p_{T}^{jet}>20$ GeV, and jet rapidities $|y^{jet}|<1.5$. The results are compared with several theoretical predictions.
The cross section for GAMMA BQUARK X production as a function of the transverse energy of the GAMMA.
The cross section for GAMMA CQUARK X production as a function of the transverse energy of the GAMMA.
The transverse momentum cross section of $e^+e^-$ pairs in the $Z$-boson mass region of 66-116 GeV/$c^2$ is precisely measured using Run II data corresponding to 2.1 fb$^{-1}$ of integrated luminosity recorded by the Collider Detector at Fermilab. The cross section is compared with quantum chromodynamic calculations. One is a fixed-order perturbative calculation at ${\cal O}(\alpha_s^2)$, and the other combines perturbative predictions at high transverse momentum with the gluon resummation formalism at low transverse momentum. Comparisons of the measurement with calculations show reasonable agreement. The measurement is of sufficient precision to allow refinements in the understanding of the transverse momentum distribution.
Total integrated cross section.
The differential PT cross section as a function of PT.
This article reports a measurement of the production cross section of prompt isolated photon pairs in proton-antiproton collisions at \sqrt{s} = 1.96 TeV using the CDF II detector at the Fermilab Tevatron collider. The data correspond to an integrated luminosity of 5.36/fb. The cross section is presented as a function of kinematic variables sensitive to the reaction mechanisms. The results are compared with three perturbative QCD calculations: (1) a leading order parton shower Monte Carlo, (2) a fixed next-to-leading order calculation and (3) a next-to-leading order/next-to-next-to-leading-log resummed calculation. The comparisons show that, within their known limitations, all calculations predict the main features of the data, but no calculation adequately describes all aspects of the data.
Diphoton production cross section as a function of the diphoton invariant mass.
Diphoton production cross section as a function of the diphoton transverse momentum.
Diphoton production cross section as a function of the azimuthal angle difference in the two photons.
We report on a CDF measurement of the total cross section and rapidity distribution, $d\sigma/dy$, for $q\bar{q}\to \gamma^{*}/Z\to e^{+}e^{-}$ events in the $Z$ boson mass region ($66<M_{ee}<116$GeV/c$^2$) produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$TeV with 2.1fb$^{-1}$ of integrated luminosity. The measured cross section of $257\pm16$pb and $d\sigma/dy$ distribution are compared with Next-to-Leading-Order(NLO) and Next-to-Next-to-Leading-Order(NNLO) QCD theory predictions with CTEQ and MRST/MSTW parton distribution functions (PDFs). There is good agreement between the experimental total cross section and $d\sigma/dy$ measurements with theoretical calculations with the most recent NNLO PDFs.
Total cross section integrated up to ABS(YRAP)=2.9.
Rapiditiy distribution of E+ E- pairs in the mass range from 66 to 116 GeV.
The cross section for photon production in association with at least one jet containing a $b$-quark hadron has been measured in proton antiproton collisions at $\sqrt{s}=1.96$ TeV. The analysis uses a data sample corresponding to an integrated luminosity of 340 pb$^{-1}$ collected with the CDF II detector. Both the differential cross section as a function of photon transverse energy $E_T^{\gamma}$, $d \sigma$($p \overline{p} \to \gamma + \geq 1 b$-jet)/$d E_T^{\gamma}$ and the total cross section $\sigma$($p \overline{p} \to \gamma + \geq 1 b$-jet/ $E_T^{\gamma}> 20$ GeV) are measured. Comparisons to a next-to-leading order prediction of the process are presented.
b + photon cross section as a function of photon ET.
b + photon total cross section for photon ET > 20 GeV.
A measurement of the cross section for the inclusive production of isolated photons by the CDF experiment at the Fermilab Tevatron collider is presented. The measurement covers the pseudorapidity region |eta^gamma|<1.0 and the transverse energy range E_T^gamma>30 GeV and is based on 2.5/fb of integrated luminosity. The sample is almost a factor of seven larger than those used for recent published results and extends the E_T^gamma coverage by 100 GeV. The result agrees with next-to-leading order perturbative QCD calculations within uncertainties over the range 50<E_Tgamma<400 GeV, though the energy spectrum in the data shows a steeper slope at lower E_T^gamma.
Measured inclusive isolated photon cross section.
We have measured the differential cross section for the inclusive production of psi(2S) mesons decaying to mu^{+} mu^{-1} that were produced in prompt or B-decay processes from ppbar collisions at 1.96 TeV. These measurements have been made using a data set from an integrated luminosity of 1.1 fb^{-1} collected by the CDF II detector at Fermilab. For events with transverse momentum p_{T} (psi(2S)) > 2 GeV/c and rapidity |y(psi(2S))| < 0.6 we measure the integrated inclusive cross section sigma(ppbar -> psi(2S)X) Br(psi(2S) -> mu^{+} mu^{-}) to be 3.29 +- 0.04(stat.) +- 0.32(syst.) nb.
The differential cross section times the dimuon branching fraction as a function of pT.
The integrated inclusive differential cross section for PSI(3685).
We present a measurement of the $\ttbar$ differential cross section with respect to the $\ttbar$ invariant mass, dSigma/dMttbar, in $\ppbar$ collisions at $\sqrt{s}=1.96$ TeV using an integrated luminosity of $2.7\invfb$ collected by the CDF II experiment. The $\ttbar$ invariant mass spectrum is sensitive to a variety of exotic particles decaying into $\ttbar$ pairs. The result is consistent with the standard model expectation, as modeled by \texttt{PYTHIA} with \texttt{CTEQ5L} parton distribution functions.
The measured differential cross section. The first error is the statistical plus jet energy scale uncertainty and the DSYS is the systematic error excluding the uncertainty in the luminosity.
The integrated cross section with statistical plus jet energy scale errors.
We have observed the reactions p+pbar --> p+X+pbar, with X being a centrally produced J/psi, psi(2S) or chi_c0, and gamma+gamma --> mu+mu-, in proton- antiproton collisions at sqrt{s} = 1.96 TeV using the Run II Collider Detector at Fermilab. The event signature requires two oppositely charged muons, each with pseudorapidity |eta| < 0.6, with M(mumu) in [3.0,4.0] GeV/c2, and either no other particles, or one additional photon, detected. The J/psi and the psi(2S) are prominent, on a continuum consistent with the QED process gamma+gamma --> mu+mu-. Events with a J/psi and an associated photon candidate are consistent with exclusive chi_c0 production through double pomeron exchange. The exclusive vector meson production is as expected for elastic photo- production, gamma+p --> J/psi(psi(2S)) + p, which is observed here for the first time in hadron-hadron collisions. The cross sections ds/dy(y=0) for p + pbar --> p + X + pbar with X = J/psi, psi(2S) orchi_c0 are 3.92+/-0.62 nb, 0.53+/-0.14 nb, and 75+/-14 nb respectively. The cross section for the continuum, with |eta(mu+/-)| < 0.6, M(mumu) in [3.0,4.0] GeV/c2, is [Integral ds/(dM.deta1.deta2)] = 2.7+/-0.5 pb, consistent with QED predictions. We put an upper limit on the cross section for odderon exchange in J/psi production: ds/dy(y=0) (J/psi_O/IP) < 2.3 nb at 95% C.L.
Prompt J/psi cross section from exclusive photoproduction at mid rapidity.
Prompt Psi(2S) cross section from exclusive photoproduction at mid rapidity.
Prompt photoproduction cross-section ratio Psi(2S)/(J/psi) at mid rapidity.
A measurement of the $\bjet$ production cross section is presented for events containing a $Z$ boson produced in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV, using data corresponding to an integrated luminosity of 2 fb$^{-1}$ collected by the CDF II detector at the Tevatron. $Z$ bosons are selected in the electron and muon decay modes. Jets are considered with transverse energy $E_T>20$ GeV and pseudorapidity $|\eta|<1.5$ and are identified as $\bjets$ using a secondary vertex algorithm. The ratio of the integrated $Z+\bjet$ cross section to the inclusive $Z$ production cross section is measured to be $3.32 \pm 0.53 {\rm (stat.)} \pm 0.42 {\rm (syst.)}\times 10^{-3}$. This ratio is also measured differentially in jet $E_T$, jet $\eta$, $Z$-boson transverse momentum, number of jets, and number of $\bjets$. The predictions from leading order Monte Carlo generators and next-to-leading-order QCD calculations are found to be consistent with the measurements within experimental and theoretical uncertainties.
Ratio of integrated Z0 + bjet cross section to inclusive Z0 production.
Ratio of the Z0 + bjet to Z0 cross section as a function of the bjet ET.
Ratio of the Z0 + bjet to Z0 cross section as a function of the bjet pseudorapidity.
We present a search for new particles whose decays produce two jets (dijets) using proton-antiproton collision data corresponding to an integrated luminosity of 1.13 fb-1 collected with the CDF II detector. The measured dijet mass spectrum is found to be consistent with next-to-leading-order perturbative QCD predictions, and no significant evidence of new particles is found. We set upper limits at the 95% confidence level on cross sections times the branching fraction for the production of new particles decaying into dijets with both jets having a rapidity magnitude |y| < 1. These limits are used to determine the mass exclusions for the excited quark, axigluon, flavor-universal coloron, E6 diquark, color-octet technirho, W', and Z'.
The measured dijet mass spectrum for both jets having rapidity from -1 to 1.
We present a measurement of the cross section for W-boson production in association with jets in pbarp collisions at sqrt(s)=1.96$ TeV. The analysis uses a data sample corresponding to an integrated luminosity of 320 pb^-1 collected with the CDF II detector. W bosons are identified in their electron decay channel and jets are reconstructed using a cone algorithm. For each W+>= n-jet sample ($n= 1 - 4$) we measure sigma(ppbar =>W+>=n$-jet)x BR(W => e nu) with respect to the transverse energy E_T of the n^th-highest E_T jet above 20 GeV, for a restricted W => e nu decay phase space. The cross sections, corrected for all detector effects, can be directly compared to particle level W+ jet(s) predictions. We present here comparisons to leading order and next-to-leading order predictions.
Measured ET differential cross section of the 1st jet in >= 1 JET plus W < E NU > events.
Measured ET differential cross section of the 2nd jet in >= 2 JET plus W < E NU > events.
Measured ET differential cross section of the 3rd jet in >= 3 JET plus W < E NU > events.
Inclusive jet cross sections in Z/gamma^* events, with Z/gamma^* decaying into an electron-positron pair, are measured as a function of jet transverse momentum and jet multiplicity in ppbar collisions at sqrt{s} = 1.96 TeV with the upgraded Collider Detector at Fermilab in Run II, based on an integrated luminosity of 1.7 fb^-1. The measurements cover the rapidity region | yjet | < 2.1 and the transverse momentum range ptjet > 30 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.
Total cross section for .GE.1JET.
Total cross section for .GE.2JET.
Total cross section for .GE.3JET.
We present a new measurement of the $B^+$ meson differential cross section $d\sigma/d p_T$ at $\sqrt{s}=1960$ GeV. The data correspond to an integrated luminosity of 739pb$^{-1}$ collected with the upgraded CDF detector (CDF II) at the Fermilab Tevatron collider. $B^+$ candidates are reconstructed through the decay $B^+ \to J/\psi K^+$, with $J/\psi \to \mu^+ \mu^-$. The integrated cross section for producing $B^+$ mesons with $p_T \geq 6$ GeV/c and $|y| \leq 1$ is measured to be $2.78 \pm 0.24 \mu$b
The differential cross section (nb/GeV/c) for B+ mesons as a function of pT.
The The B+ production cross section.
We present a new measurement of the inclusive and differential production cross sections of $J/\psi$ mesons and $b$-hadrons in proton-antiproton collisions at $\sqrt{s}=1960$ GeV. The data correspond to an integrated luminosity of 39.7 pb$^{-1}$ collected by the CDF Run II detector. We find the integrated cross section for inclusive $J/\psi$ production for all transverse momenta from 0 to 20 GeV/$c$ in the rapidity range $|y|<0.6$ to be $4.08 \pm 0.02 (stat)^{+0.36}_{-0.33} (syst) \mu {\rm b}$. We separate the fraction of $J/\psi$ events from the decay of the long-lived $b$-hadrons using the lifetime distribution in all events with $p_T(J/\psi) > 1.25$ GeV/$c$. We find the total cross section for $b$-hadrons, including both hadrons and anti-hadrons, decaying to $J/\psi$ with transverse momenta greater than 1.25 GeV/$c$ in the rapidity range $|y(J/\psi)|<0.6$, is $ 0.330 \pm 0.005 (stat) ^{+0.036}_{-0.033} (syst) ~\mu{\rm b}$. Using a Monte Carlo simulation of the decay kinematics of $b$-hadrons to all final states containing a $J/\psi$, we extract the first measurement of the total single $b$-hadron cross section down to zero transverse momentum at $\sqrt{s}=1960$ GeV. We find the total single $b$-hadron cross section integrated over all transverse momenta for $b$-hadrons in the rapidity range $|y|<0.6$ to be $ 17.6 \pm 0.4 (stat)^{+2.5}_{-2.3} (syst) \mu{\rm b}$.
Integrated J/PSI cross section shown both uncorrected and corrected for branching ratio (5.88+-0.10PCT) of J/PSI into mu+mu-. Systematic error includes pT-dependent and fully correlated errors added in quadrature.
Differential cross section times branching ratio (5.88+-0.10PCT) into mu+mu- as a function of transverse momentum for the rapidity range -0.6 to 0.6 at a centre-of-mass energy of 1960 GeV.
Integrated bottom-hadron prouction cross section shown both uncorrected andcorrected for branching ratio (5.88+-0.10PCT) of J/PSI into mu+mu-. Systematic error includes pT-dependent and fully correlated errors added in quadrature.
We report a measurement of the rate of prompt diphoton production in $p\bar{p}$ collisions at $\sqrt{s}=1.96 ~\hbox{TeV}$ using a data sample of 207 pb$^{-1}$ collected with the upgraded Collider Detector at Fermilab (CDF II). The background from non-prompt sources is determined using a statistical method based on differences in the electromagnetic showers. The cross section is measured as a function of the diphoton mass, the transverse momentum of the diphoton system, and the azimuthal angle between the two photons and is found to be consistent with perturbative QCD predictions.
Cross section as a function of the diphoton mass.
Cross section as a function of the diphoton transverse momentum.
Cross section as a function of the diphoton azimuthal angle difference.
We report on measurements of differential cross sections d sigma/d p_t for prompt charm meson production in p anti-p collisions at s**(1/2) = 1.96 TeV using 5.8 +/- 0.3 pb-1 of data from the CDF II detector at the Fermilab Tevatron. The data are collected with a new trigger that is sensitive to the long lifetime of hadrons containing heavy flavor. The charm meson cross sections are measured in the central rapidity region |y| \leq 1 in four fully reconstructed decay modes: D0 --> K- pi+, D*+ -> D0 pi+, D+ --> K- pi+ pi+, D+_s--> phi pi+, and their charge conjugates. The measured cross sections are compared to theoretical calculations.
Measured prompt charm production cross sections for ABS(YRAP) < 1. The branching ratios used are (D0:3.81 +- 0.09 PCT), (D+:2.57 +- 0.06 PCT),(D+:9.1 +- 0.6 PCT) and (D/S+:1.8 +- 0.5 PCT).
The inclusive cross section for J/ψ production times the branching ratio B(J/ψ→μ+μ−) has been measured in the forward pseudorapidity region: B×dσ[p¯+p→J/ψ(pT>10GeV/c,2.1<|η|<2.6)+X]/dη=192±9(stat)±29(syst)pb. The results are based on 74.1±5.2pb−1 of data collected by the CDF Collaboration at the Fermilab Tevatron Collider. The measurements extend earlier measurements of the D0 Collaboration to higher pTJ/ψ. In the kinematic range where the experiments partially overlap, these data are in good agreement with previous measurements.
The integrated cross section for J/PSI --> MU+ MU- decay.
Cross section as a function of PT. Statistical errors only.
We present measurements of the B+ meson total cross section and differential cross section $d\sigma/ dp_T$. The measurements use a $98\pm 4$ pb^{-1} sample of $p \bar p$ collisions at $\sqrt{s}=1.8$ TeV collected by the CDF detector. Charged $B$ meson candidates are reconstructed through the decay $B^{\pm} \to J/\psi K^{\pm}$ with $J/\psi\to \mu^+ \mu^-$. The total cross section, measured in the central rapidity region $|y|<1.0$ for $p_T(B)>6.0$ GeV/$c$, is $3.6 \pm 0.6 ({\rm stat} \oplus {\rm syst)} \mu$b. The measured differential cross section is substantially larger than typical QCD predictions calculated to next-to-leading order.
Measured differential cross section for B+ production. The first (DSYS) error is the PT dependent systematic error and the second is the full correlated systematic error.
The total integrated B+ meson cross section. The first error is the combined statistical and PT dependent systematic error. The DSYS error is the fully correlated systematic error.
We present a measurement of the cross section and the first measurement of the heavy flavor content of associated direct photon + muon events produced in hadronic collisions. These measurements come from a sample of 1.8 TeV ppbar collisions recorded with the Collider Detector at Fermilab. Quantum chromodynamics (QCD) predicts that these events are primarily due to Compton scattering process charm+gluon -> charm+photon, with the final state charm quark producing a muon. The cross section for events with a photon transverse momentum between 12 and 40 GeV/c is measured to be 46.8+-6.3+-7.5 pb, which is two standard deviations below the most recent theoretical prediction. A significant fraction of the events in the sample contain a final-state bottom quark. The ratio of charm to bottom production is measured to be 2.4+-1.2, in good agreement with QCD models.
The measured photon-muon cross section.
Measured cross section in the PT interval 12-40 GeV.
We report on a measurement of the mass dependence of the forward-backward charge asymmetry, A_FB, and production cross section dsigma/dM for e+e- pairs with mass M_ee>40 GeV/c2. The data sample consists of 108 pb-1 of p-pbar collisions at sqrt(s)=1.8 TeV taken by the Collider Detector at Fermilab during 1992-1995. The measured asymmetry and dsigma/dM are compared with the predictions of the Standard Model and a model with an extra Z' gauge boson.
The E+ E- production cross section and the forward-backward asymmetry. The errors contain the statistical and systematic uncertainties combined in quadrature, but not the additional uncertainty of the luminosity.
The forward, backward and total production cross sections for dielectron production for the mass regions above 105 GeV. The errors contain the statistical and systematic uncertainties combined in quadrature, but not the additional uncertainty of the luminosity.
The production cross section for di-muons for the mass region above 105 GeV. The errors contain the statistical and systematic uncertainties combined in quadrature, but not the additional uncertainty of the luminosity.
We present results of searches for diphoton resonances produced both inclusively and also in association with a vector boson (W or Z) using 100 $pb^{-1}$ of $p\bar{p}$ collisions using the CDF detector. We set upper limits on the product of cross section times branching ratio for both $p\bar{p} \to \gamma \gamma + X$ and $p \bar{p} \to \gamma \gamma + W/Z$. Comparing the inclusive production to the expectations from heavy sgoldstinos we derive limits on the supersymmetry-breaking scale $\sqrt{F}$ in the TeV range, depending on the sgoldstino mass and the choice of other parameters. Also, using a NLO prediction for the associated production of a Higgs boson with a W or Z boson, we set an upper limit on the branching ratio for $H \to \gamma \gamma$. Finally, we set a lower limit on the mass of a 'bosophilic' Higgs boson (e.g. one which couples only to $\gamma, W,$ and $Z$ bosons with standard model couplings) of 82 GeV/$c^2$ at 95% confidence level.
No description provided.
No description provided.
We present results from the measurement of the inclusive jet cross section for jet transverse energies from 40 to 465 GeV in the pseudo-rapidity range $0.1<|\eta|<0.7$. The results are based on 87 $pb^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron Collider. The data are consistent with previously published results. The data are also consistent with QCD predictions given the flexibility allowed from current knowledge of the proton parton distributions. We develop a new procedure for ranking the agreement of the parton distributions with data and find that the data are best described by QCD predictions using the parton distribution functions which have a large gluon contribution at high $E_T$ (CTEQ4HJ).
The inclusive jet cross section. Statistical errors shown. The systematic errors are given in the html link above.
A measurement is presented of the two-jet differential cross section, d^3\sigma/dE_T d\eta_1 d\eta_2, at center of mass energy sqrt{s} = 1800 GeV in proton-antiproton collisions. The results are based on an integrated luminosity of 86 pb^-1 collected during 1994-1995 by the CDF collaboration at the Fermilab Tevatron collider. The differential cross section is measured as a function of the transverse energy, E_T, of a jet in the pseudorapidity region 0.1 < |eta_1| < 0.7 for four different pseudorapidity bins of a second jet restricted to 0.1 < |\eta_2| < 3.0. The results are compared with next-to-leading order QCD calculations determined using the CTEQ4 and MRST sets of parton distribution functions. None of the sets examined in this analysis provides a good description of the data.
The measured dijet differential cross section with the second jet in the ABS(ETARAP) range 0.1 to 0.7.
The measured dijet differential cross section with the second jet in the ABS(ETARAP) range 0.7 to 1.4.
The measured dijet differential cross section with the second jet in the ABS(ETARAP) range 1.4 to 2.1.
We report on the first measurement of the rapidity distribution dsigma/dy over nearly the entire kinematic region of rapidity for e^+e^- pairs in the Z-boson region of 66<M_{ee}<116 GeV/c^2 and at higher mass M_{ee}>116 GeV/c^2. The data sample consists of 108 pb^{-1} of ppbar collisions at \sqrt{s}=1.8 TeV taken by the Collider Detector at Fermilab during 1992--1995. The total cross section in the $Z$-boson region is measured to be 252 +- 11 pb. The measured total cross section and d\sigma/dy are compared with quantum chromodynamics calculations in leading and higher orders.
No description provided.
We present a measurement of the cross section for production of two or more jets as a function of dijet mass, based on an integrated luminosity of 86 pb^-1 collected with the Collider Detector at Fermilab. Our dijet mass spectrum is described within errors by next-to-leading order QCD predictions using CTEQ4HJ parton distributions, and is in good agreement with a similar measurement from the D0 experiment.
The differential cross section for two or more jets as a function of the dijet mass.
The transverse momentum and total cross section of e^+e^- pairs in the Z-boson region of 66<M_{ee}<116 GeV$/c^2$ from $p\bar{p}$ collisions at $\sqrt{s}=1.8$ TeV are measured using 110 pb^{-1} of collisions taken by the Collider Detector at Fermilab during 1992-1995. The total cross section is measured to be $248 \pm 11$ pb. The differential transverse momentum cross section is compared with calculations that match quantum chromodynamics perturbation theory at high transverse momentum with the gluon resummation formalism at low transverse momentum.
The measured transverse momentum distribution of e+e- pairs in the Z0 bosonregion. PT is the centre of the bins.
The total cross section for e+e- pair production in the Z0 region. The mainerror is the statistical and efficiency error, the first DSYS error is the syst ematic error from the background subtractions and the second DSYS error is from the collision luminosity.
We present a measurement of the differential cross section dσ/dΣETjet for the production of multijet events in pp¯ collisions where the sum is over all jets with transverse energy ETjet>ETmin. The measured cross section for events with ΣETjet>320GeV is compared to O(αs3) perturbative QCD predictions and QCD parton shower Monte Carlo predictions. The agreement between the O(αs3) predicted and observed event rates is reasonable for ETmin=100GeV, but poorer for ETmin=20GeV.
The ET shown here (unless specified otherwise) is the sum of all the jets' individual ETs. All jets are required to have the absolute values of their pseudorapidity < 4.2 and data are given for two different minimum ET cut-offs.. The errors given are statistical only.
Integrated cross sections. Again ET is the sum of the individual ETs of thejets.
We present a study of J/ψ and ψ(2S) production in pp¯ collisions, at s=1.8TeV with the CDF detector at Fermilab. The J/ψ and ψ(2S) mesons are reconstructed using their μ+μ− decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, |η|<0.6. We also measure the fraction of these events originating from b hadrons. We thus extract individual cross sections for J/ψ and ψ(2S) mesons from b-quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct ψ(2S) production compared with predictions from the color singlet model.
Integrated cross sections.
Differential cross section times branching ratio for J/PSI's originating from b hadron decays.
Differential cross section times branching ratio for PSI(2S) originating from b hadron decays.
We have measured the fraction of J/ψ mesons originating from χc meson decays in pp¯ collisions at s=1.8TeV. The fraction, for PTJ/ψ>4.0GeV/c and |ηJ/ψ|<0.6, not including contributions from b flavored hadrons, is 29.7%±1.7%(stat)±5.7%(syst). We have determined the cross sections for J/ψ mesons originating from χc decays and for directly produced J/ψ mesons. We have found that direct J/ψ production is in excess of the prediction of the color singlet model by the same factor found for direct ψ(2S) production.
Fraction of J/PSI mesons from CHI/C decays, excluding the the contributions from b-hadron decay.
Differential cross section for J/PSI's directly produced (ie excluding CHI/C and PSI/(25) decay contribution to the prompt production cross section). RE = PBAR P --> J/PSI X.
Differential cross section for J/PSI's produced in CHI/C decays.
The inclusive jet differential cross section has been measured for jet transverse energies, $E_T$, from 15 to 440 GeV, in the pseudorapidity region 0.1$\leq | \eta| \leq $0.7. The results are based on 19.5 pb$~{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with $E_T>200$\ GeV is significantly higher than current predictions based on O($\alpha_s~3$) perturbative QCD calculations. Various possible explanations for the high-$E_T$\ excess are discussed.
No description provided.
We report on measurements of the ϒ(1S), ϒ(2S), and ϒ(3S) differential, (d2σdPtdy)y=0, and integrated cross sections in pp¯ collisions at s=1.8 TeV using a sample of 16.6 ± 0.6 pb−1 collected by the Collider Detector at Fermilab. The three resonances were reconstructed through the decay ϒ→μ+μ−. Comparison is made to a leading order QCD prediction.
SIG*Br(UPSI --> MU+ MU-).
SIG*Br(UPSI --> MU+ MU-).
SIG*Br(UPSI --> MU+ MU-).
This paper presents the first direct measurement of the $B$ meson differential cross section, $d\sigma/dp_T$, in $p\overline{p}$ collisions at $\sqrt{s}=1.8$ TeV using a sample of $19.3 \pm 0.7$ pb$~{-1}$ accumulated by the Collider Detector at Fermilab (CDF). The cross section is measured in the central rapidity region $|y| < 1$ for $p_T(B) > 6.0$ GeV/$c$ by fully reconstructing the $B$ meson decays $B~{+}\rightarrow J/\psi K~{+}$ and $B~{0}\rightarrow J/\psi K~{*0}(892)$, where $J/\psi \rightarrow \mu~+\mu~-$ and $K~{*0} \rightarrow K~+ \pi~-$. A comparison is made to the theoretical QCD prediction calculated at next-to-leading order.
Charged B meson cross section.
Average B meson cross section (including charged and neutral).
Total integrated B meson cross section above 6 GeV.
The charge asymmetry has been measured using $19,039W$ decays recorded by the CDF detector during the 1992-93 run of the Tevatron Collider. The asymmetry is sensitive to the ratio of $d$ and $u$ quark distributions to $x<0.01$ at $Q~2 \approx M_W~2$, where nonperturbative effects are minimal. It is found that of the two current sets of parton distributions, those of Martin, Roberts and Stirling (MRS) are favored over the sets most recently produced by the CTEQ collaboration. The $W$ asymmetry data provide a stronger constraints on $d/u$ ratio than the recent measurements of $F_2~{\mu n}/F_2~{\mu p}$ which are limited by uncertainties originating from deutron corrections.
Charge asymmetry defined as (DSIG(Q=L+)/DYRAP - DSIG(Q=L-)/DYRAP)/ (DSIG(Q=L+)/DYRAP + DSIG(Q=L-)/DYRAP). Here LEPTON are E and MU.
Antiproton-proton elastic scattering was measured at c.m.s. energies √s =546 and 1800 GeV in the range of four-momentum transfer squared 0.025<-t<0.29 GeV2. The data are well described by the exponential form ebt with a slope b=15.28±0.58 (16.98±0.25) GeV−2 at √s =546 (1800) GeV. The elastic scattering cross sections are, respectively, σel=12.87±0.30 and 19.70±0.85 mb.
Final results (systematic errors included).
Final results (systematic errors included).
Statistical errors only. Data supplied by S. Belforte.
The dijet invariant mass distribution has been measured in the region between 140 and 1000 GeV/c2, in 1.8 TeV p p¯ collisions. Data collected with the Collider Detector at Fermilab show agreement with QCD calculations. A limit on quark compositeness of Λc>1.3 TeV is obtained. Axigluons with masses between 240 and 640 GeV/c2 are excluded at 95% C.L. if we assume ten open decay channels. Model-independent limits on the production of heavy particles decaying into two jets are also presented.
No description provided.
The dijet invariant mass distribution has been measured in the region between 120 and 1000 GeV/c2, in 1.8-TeV pp¯ collisions. The data sample was collected with the Collider Detector at Fermilab (CDF). Data are compared to leading order (LO) and next-to-leading order (NLO) QCD calculations using two different clustering cone radii R in the jet definition. A quantitative test shows good agreement of data with the LO and NLO QCD predictions for a cone of R=1. The test using a cone of R=0.7 shows less agreement. The NLO calculation shows an improvement compared to LO in reproducing the shape of the spectrum for both radii, and approximately predicts the cone size dependence of the cross section.
Observed cross section using R = 1.0. The second systematic error is the theoretical uncertainty and includes only the effect of the out-of-cone losses, the underlying event energy, and the contribution of multi-jet events.
Observed cross section using R = 0.7. The second systematic error is the theoretical uncertainty and includes only the effect of the out-of-cone losses, the underlying event energy, and the contribution of multi-jet events.
We present measurements from events with two isolated prompt photons in p¯p collisions at √s =1.8 TeV. The differential cross section, measured as a function of transverse momentum (PT) of each photon, is about 3 times what next-to-leading-order QCD calculations predict. The cross section for photons with PT in the range 10–19 GeV is 86±27(stat)−23+32(syst) pb. We also study the correlation between the two photons in both azimuthal angle and PT. The magnitude of the vector sum of the transverse momenta of both photons, KT=‖PT1+PT2‖, has a mean value of 〈KT〉=5.1±1.1 GeV.
No description provided.
No description provided.
Vector sum of the photons transvserse momenta.. Errors contain both statistics and systematics.. Data read from plots.
Inclusive jet cross sections have been measured in p¯p collisions at √s =546 and 1800 GeV, using the Collider Detector at Fermilab. The ratio of jet cross sections is compared to predictions from simple scaling and O(as3) QCD. Our data exclude scaling and lie (1.5–2.4)σ below a range of QCD predictions.
Additional systematic uncertainty +23,-26 pct.
Additional systematic uncertainty +-16 pct.
Additional systematic uncertainty +-0.22.
Inclusive J/ψ and ψ(2S) production has been studied in p¯p collisions at √s =1.8 TeV using 2.6±0.2 pb−1 of data taken with the Collider Detector at Fermilab. The products of production cross section times branching fraction were measured as functions of PT for J/ψ→μ+μ− and ψ(2S)→μ+μ−. In the kinematic range PT>6 GeV/c and ‖η‖≤0.5 we get σ(p¯p→J/ψ X)B(J/ψ→μ+μ−) =6.88±0.23(stat)−1.08+0.93(syst) nb, and σ(p¯p→ψ(2S)X)B(ψ(2S)→μ+μ−) =0.232±0.051(stat)−0.032+0.029(syst)nb. From these values we calculate the inclusive b-quark production cross section.
Cross section times the branching ratio into mu+ mu- pairs.
Cross section times the branching ratio into mu+ mu- pairs.
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The charge asymmetry of leptons from W-boson decay has been measured using p¯p data from the Collider Detector at Fermilab at √s =1.8 TeV. The observed asymmetry is well described by most of the available parton distributions.
Electrons in the central region.
Muons in the central region.
Plug electrons.
We present a measurement of the inclusive jet cross section in p¯p collisions at √s =1.8 TeV at the Fermilab Tevatron using the Collider Detector at Fermilab. Good agreement is seen with the predictions of recent next-to-leading-order [O(αs3)] QCD predictions. The dependence of the cross section on clustering cone size is reported for the first time. An improved limit on Λc, a term characterizing possible quark substructure, is set at 1.4 TeV (95% C.L.).
Data are averaged over the pseudorapidity interval 0.1 to 0.7.
We have measured the Z-boson production differential cross section as a function of transverse momentum using Z→ee and Z→μμ decays in p¯p collision at √s =1.8 TeV with the Collider Detector at Fermilab. Comparison with standard-model predictions shows good agreement over the range 0<pT<160 GeV/c available from this data sample.
Errors are systematic and statistical combined, and are correlated bin to bin due to the correction for resolution smearing.
Using the Collider Detector at Fermilab, the W-boson differential cross section dσ/dPT is measured using W→eν events in proton-antiproton collisions at √s =1.8 TeV. A next-to-leading-order theoretical calculation agrees well with the data. The cross section (σ) for PT>50 GeV/c is measured to be 423±58(stat)±108(syst) pb.
No description provided.
No description provided.
We present the dijet invariant-mass distribution in the region between 60 and 500 GeV, measured in 1.8-TeV p¯p collisions in the Collider Detector at Fermilab. Jets are restricted to the pseudorapidity interval |η|<0.7. Data are compared with QCD calculations; axigluons are excluded with 95% confidence in the region 120<MA<210 GeV for axigluon width ΓA=NαsMA6, with N=5.
Corrected mass distributions for jets restricted to the pseudorapidity region ABS(ETARAP) <0.7.
We have measured dijet angular distributions at √s =1.8 TeV with the Collider Detector at Fermilab and the Tevatron p¯p Collider and find agreement with leading-order QCD. By comparing the distribution for the highest dijet invariant masses with the prediction of a model of quark compositeness, we set a lower limit on the associated scale parameter Λc at 330 GeV (95% C.L.).
Numerical values read from figure in preprint.
Inclusive jet production at s=1.8 TeV has been measured in the CDF detector at the Fermilab Tevatron p¯p Collider. Jets with transverse energies (Et) up to 250 GeV have been observed. The Et dependence of the inclusive jet cross section is consistent with leading-order quantum-chromodynamic calculations, and comparison with lower-energy data shows deviations from scaling consistent with QCD. A lower limit of 700 GeV (95% confidence level) is placed on the quark compositeness scale parameter Λc associated with an effective contact interaction.
No description provided.