21 research outputs found

    Publisher’s Note: Search for scalar leptoquark pairs decaying to νν ̄qq ̄ in pp ̄ collisions at s=1.96 TeV [Phys. Rev. D 71, 112001 (2005)]

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    Measurement of the J/psi meson and b-hadron production cross sections in p(p)over-bar collisions at root s=1960 GeV

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    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 roots=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|\u3c0.6 to be 4.08+/-0.02(stat)(-0.33)(+0.36)(syst) mub. 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)\u3e1.25 GeV/c. We find the total cross section for b hadrons, including both hadrons and antihadrons, decaying to J/psi with transverse momenta greater than 1.25 GeV/c in the rapidity range |y(J/psi)|\u3c0.6 is 0.330+/-0.005(stat)(-0.033)(+0.036)(syst) mub. 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 roots=1960 GeV. We find the total single b-hadron cross section integrated over all transverse momenta for b hadrons in the rapidity range |y|\u3c0.6 to be 17.6+/-0.4(stat)(-2.3)(+2.5)(syst) mub

    Search for scalar leptoquark pairs decaying to v(v)over-barq(q)over-bar in p(p)over-bar collisions at root s=1.96 TeV

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    We report on a search for the pair production of scalar leptoquarks (LQ), using 191 pb(-1) of proton-antiproton collision data recorded by the CDF experiment during Run II of the Tevatron. The leptoquarks are sought via their decay into a neutrino and quark yielding missing transverse energy and several jets of large transverse energy. No evidence for LQ production is observed, and limits are set on sigma(p (p) over bar -\u3e LQ (LQ) over barX -\u3e v (v) over barq (q) over barX). Using a next-to-leading order theoretical prediction of the cross section for LQ production, we exclude first-generation LQ in the mass interval 78 to 117 GeV/c(2) at the 95% confidence level for BR(LQ -\u3e vq)=100%

    Search for excited and exotic electrons in the e gamma decay channel in p(p)over-bar collisions at root s=1.96 TeV

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    We present a search for excited and exotic electrons (e(*)) decaying to an electron and a photon, both with high transverse momentum. We use 202 pb(-1) of data collected in p (p) over bar collisions at root s =1.96 TeV with the Collider Detector at Fermilab II detector. No signal above standard model expectation is seen for associated ee(*) production. We discuss the e(*) sensitivity in the parameter space of the excited electron mass M-e(*) and the compositeness energy scale Lambda. In the contact interaction model, we exclude 132 GeV/c(2)< M-e*< 879 GeV/c(2) for Lambda=M-e* at 95% confidence level (C.L.). In the gauge-mediated model, we exclude 126 GeV/c(2)< M-e*< 430 GeV/c(2) at 95% C.L. for the phenomenological coupling f/Lambda approximate to 10(-2) GeV-1

    First measurements of inclusive W and Z cross sections from Run II of the Fermilab Tevatron Collider

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    We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for p (p) over bar collisions at root s=1.96 TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72 pb(-1) recorded with the CDF detector at the Fermilab Tevatron. We test e-mu universality in W decays, and we measure the ratio of leptonic W and Z rates from which the leptonic branching fraction B(W -> l nu) can be extracted as well as an indirect value for the total width of the W and the Cabibbo-Kobayashi-Maskawa matrix element, vertical bar V(cs)vertical bar

    Search for ZZ and ZW production in pp(-) collisions at root s=1.96 TeV

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    We present a search for ZZ and ZW vector boson pair production in p (p) over bar collisions at root z = 1.96 TeV using the leptonic decay channels ZZ -\u3e ll nu nu, ZZ -\u3e lll(\u27)l(\u27), and ZW -\u3e lll(\u27)v. In a data sample corresponding to an integrated luminosity of 194 pb(-1) collected with the Collider Detector at Fermilab, 3 candidate events are found with an expected background of 1.0 +/- 0.2 events. We set a 95% confidence level upper limit of 15.2 pb on the cross section for ZZ plus ZW production, compared to the standard model prediction of 5.0 +/- 0.4 pb

    Measurement of the forward-backward charge asymmetry of electron-positron pairs in (p)over-barp collisions at root s=1.96 TeV

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    We present a measurement of the mass dependence of the forward-backward charge asymmetry (A(FB)) for e(+)e(-) pairs produced via an intermediate Z/gamma(*) with mass M-ee \u3e 40 GeV/c(2). We study the constraints on the Z-quark couplings imposed by our measurement. We analyze an integrated luminosity of 72 pb(-1) collected by the CDF-II detector in (p) over barp collisions at root s = 1.96 TeV at the Fermilab Tevatron. A comparison of the uncorrected AFB between data and standard model Monte Carlo gives good agreement with a chi(2)/DOF of 15.7/15. The couplings measurements are also consistent with standard model predictions

    Measurement of partial widths and search for direct CP violation in D-0 meson decays to K-K+ and pi(-)pi(+)

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    We present a measurement of relative partial widths and decay rate CP asymmetries in K-K+ and pi(-)pi(+) decays of D-0 mesons produced in p(p) over bar collisions at root s = 1.96 TeV. We use a sample of 2x10(5) D*+-> D-0 pi(+) (and charge conjugate) decays with the D-0 decaying to K-pi(+), K-K+, and pi(-)pi(+), corresponding to 123 pb(-1) of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure Gamma(D-0 -> K-K+)/Gamma(D-0 -> K-pi(+)) = 0.0992 +/- 0.0011 +/- 0.0012, Gamma(D-0 ->pi(-)pi(+))/Gamma(D-0 -> K-pi(+)) = 0.035 94 +/- 0.000 54 +/- 0.000 40, A(CP)(K-K+) = (2.0 +/- 1.2 +/- 0.6)%, and A(CP)(pi(-)pi(+)) = (1.0 +/- 1.3 +/- 0.6)%, where, in all cases, the first uncertainty is statistical and the second is systematic

    Measurement of the W+W- production cross section in p(p)over-bar collisions at root s=1.96 TeV using dilepton events

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    We present a measurement of the W+W- production cross section using 184 pb(-1) of p (p) over bar collisions at a center-of-mass energy of 1.96 TeV collected with the Collider Detector at Fermilab. Using the dilepton decay channel W+W--> l(+)nu l(-)(nu) over bar, where the charged leptons can be either electrons or muons, we find 17 candidate events compared to an expected background of 5.0(-0.8)(+2.2) events. The resulting W+W- production cross-section measurement of sigma(p (p) over bar -> W+W-)=14.6(-5.1)(+5.8)(stat)(-3.0)(+1.8)(syst)+/- 0.9(lum) pb agrees well with the standard model expectation

    Search for electroweak single-top-quark production in p(p)over-bar collisions at root s=1.96 TeV

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    We report on a search for standard model t-channel and s-channel single-top quark production in p (p) over bar collisions at a center of mass energy of 1.96 TeV. We use a data sample corresponding to 162 pb(-1) recorded by the upgraded collider detector at Fermilab. We find no significant evidence for electroweak top quark production and set upper limits at the 95% confidence level on the production cross section, consistent with the standard model: 10.1 pb for the t-channel, 13.6 pb for the s-channel and 17.8 pb for the combined cross section of t- and s-channel
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