We report on measurements of inclusive cross sections times branching fractions into electrons for W and Z bosons produced in ppbar collisions at sqrts=1.8 TeV.From an integrated luminosity of 84.5 inverse pb recorded in 1994--1995 using the D0 detector at the Fermilab Tevatron, we determine sigma(ppbar->W+X)B(W->e nu) = 2310 +- 10(stat) +- 50(syst) +- 100(lum) pb and sigma(ppbar->Z+X)B(Z->e e) = 221 +- 3(stat) +- 4(syst) +- 10(lum) pb. From these, we derive their Ratio R = 10.43 +- 0.15(stat) +- 0.20(syst) +- 0.10(NLO), B(W->e nu) = 0.1066 +- 0.0015(stat) +- 0.0021(syst) +- 0.0011(theory)+- 0.0011(NLO), and Gamma_W = 2.130 +- 0.030(stat) +- 0.041(syst) +- 0.022(theory) +- 0.021(NLO) GeV. We use the latter to set a 95% confidence level upper limit on the partial decay width of the W boson into non-standard model final states, Gamma_W^{inv}, of 0.168 GeV. Combining these results with those from the 1992--1993 data gives R = 10.54 +- 0.24, Gamma_W = 2.107 +- 0.054 GeV, and a 95% C.L. upper limit on Gamma_W^{inv} of 0.132 GeV. Using a sample with a luminosity of 505 inverse nb taken at sqrts=630 GeV, we measure sigma(ppbar->W+X)B(W->e nu) = 658 +- 67 pb.
Cross sections times branching ratios for W+- and Z0 production. The second DSYS error is due to the uncertainty in the luminosity.
Ratio of W to Z0 cross sections. The second systematic error is due to the uncertainty in the NLO electroweak radiative corrections.
Using data recorded by the CLEO II detector at CESR, we report evidence for two new charmed baryons, one decaying into $\Xi_c^+\pi^+\pi^-$ via an intermediate $\Xi_c^{*0}$, and its isospin partner decaying into $\Xi_c^0\pi^+\pi^-$ via an intermediate $\Xi_c^{*+}$. We measure the mass differences of the two states to be $M(\Xi_c^+\pi^+\pi^-)-M(\Xi_c^+)=$ $348.6\pm0.6\pm1.0$ MeV, and $M(\Xi_c^0\pi^+\pi^-)-M(\Xi_c^0)=$ $347.2\pm0.7\pm2.0$ MeV. We interpret these new states as the $J^P = {3 \over{2}}^- $ $\Xi_{c1}$ particles, the charmed-strange analogues of the $\Lambda_{c1}^+(2625)$.
CONST(NAME=EPS) is the parameter of the Peterson fragmentation function (C.Peterson et al., PR D27, 105 (1983)) D(N)/D(Z) = FD(Z) = const * (1/Z)*1/(1 - ( 1/Z)-CONST(NAME=EPS)/(1-Z))**2. The data for all baryons are combined together.
We present measurements of the b-bbar production cross section and angular correlations using the D0 detector at the Fermilab Tevatron p-pbar Collider operating at sqrt(s) = 1.8 TeV. The b quark production cross section for |y(b)|<1.0 and p_T(b)>6 GeV/c is extracted from single muon and dimuon data samples. The results agree in shape with the next-to-leading order QCD calculation of heavy flavor production but are greater than the central values of these predictions. The angular correlations between b and bbar quarks, measured from the azimuthal opening angle between their decay muons, also agree in shape with the next-to-leading order QCD prediction.
No description provided.
The errors are combinations of statistical and systematic uncertainties.
The distribution of MU+ MU- azimuthal angle difference.
Evidence of anomalous WW and WZ production was sought in pbar{p} collisions at a center-of-mass energy of sqrt(s) = 1.8 TeV. The final states $WW (WZ) to mu-nu-jet-jet + X, WZ to mu-nu-e-e + X and WZ to e-nu-e-e + X were studied using a data sample corresponding to an integrated luminosity of approximately 90 pb-1. No evidence of anomalous diboson production was found. Limits were set on anomalous WWgamma and WWZ couplings and were combined with our previous results. The combined 95% confidence level anomalous coupling limits for Lambda=2 TeV are -0.25 LE Delta-kappa LE 0.39 (lambda=0) and -0.18 LE lambda LE 0.19 (Delta \kappa = 0), assuming the WWgamma couplings are equal to the WWZ couplings.
CONST(NAME=SCALE) is the model parameter, used in the modification of the couplings as follows: g = g0/(1 + M(gamma Z)**2/CONST(NAME=SCALE)**2)**n. KAPPA_GZ means KAPPA_GAMMA = KAPPA_Z. LAMBDA_GZ means LAMBDA_GAMMA = LAMBDA_Z.
CONST(NAME=SCALE) is the model parameter, used in the modification of the couplings as follows: g = g0/(1 + M(gamma Z)**2/CONST(NAME=SCALE)**2)**n.
Using a sample of 3.3 million Upsilon(4S) -> BBbar events collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we measure the branching fraction for B -> rho l nu, |V_ub|, and the partial rate (Delta Gamma) in three bins of q^2 = (p_B-p_rho)^2. We find B(B^0 -> rho^- l^+ nu)=(2.69 +- 0.41^+0.35_-0.40 +- 0.50) 10^-4, |V_ub|=(3.23 +- 0.24^+0.23_-0.26 +- 0.58) 10^-3, Delta Gamma (0 < q^2 < 7 GeV^2/c^4) =(7.6 +- 3.0 ^+0.9_-1.2 +- 3.0) 10^-2 ns^-1, Delta Gamma (7 < q^2 < 14 GeV^2/c^4) =(4.8 +- 2.9 ^+0.7_-0.8 +- 0.7) 10^-2 ns^-1, and Delta Gamma (14 < q^2 < 21 GeV^2/c^4) = (7.1 +- 2.1^+0.9_-1.1 +- 0.6)10^-2 ns^-1. The quoted errors are statistical, systematic, and theoretical. The method is sensitive primarily to B -> rho l nu decays with leptons in the energy range above 2.3 GeV. Averaging with the previously published CLEO results, we obtain B(B^0 -> rho^- l^+ nu) = (2.57 +- 0.29^+0.33_-0.46 +- 0.41) 10^-4 and |V_{ub}| = (3.25 +- 0.14 ^+0.21_-0.29 +- 0.55) 10^-3.
VCB is the V-CKM (Cabibbo-Kobayashi-Maskawa) mixing matrix element. LEPTON+- stands for E+- or MU+-.
The isoscalar structure functions $xF_3$ and $F_2$ are measured as functions of $x$ averaged over all $Q^2$ permissible for the range of 6 to 28 GeV of incident neutrino (anti-neutrino) energy at the IHEP-JINR Neutrino Detector. The QCD analysis of $xF_3$ structure function provides $\Lambda_{\bar{MS}}^{(4)} = (411 \pm 200)$ MeV under the assumption of QCD validity in the region of low $Q^2$. The corresponding value of the strong interaction constant $\alpha_S (M_Z) = 0.123^{+0.010}_{-0.013}$ agrees with the recent result of the CCFR collaboration and with the combined LEP/SLC result.
No description provided.
No description provided.
We report on a search for bottom squarks produced in pbarp collisions at sqrt(s) = 1.8 TeV using the D0 detector at Fermilab. Bottom squarks are assumed to be produced in pairs and to decay to the lightest supersymmetric particle (LSP) and a b quark with branching fraction of 100%. The LSP is assumed to be the lightest neutralino and stable. We set limits on the production cross section as a function of bottom squark mass and LSP mass.
It is assumed that the S-BQ decays intp BQ and LSP with a branching fraction of 100%.
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No description provided.
No description provided.
No description provided.
Measurements at 18 beam kinetic energies between 1975 and 2795 MeV and at 795 MeV are reported for the pp elastic-scattering single spin parameter Aooon=Aoono=AN=P. The c.m. angular range is typically 60–100°. These results are compared to previous data from Saturne II and other accelerators. A search for energy-dependent structure at fixed c.m. angles is performed, but no rapid changes are observed.
Measured values of the P P analysing power at kinetic energy 0.795 GeV. Therelative and additive systematic errors are +- 0.018 and 0.0007.
Measured values of the P P analysing power at kinetic energy 1.975 GeV. Therelative and additive systematic errors are +- 0.045 and 0.002.
Measured values of the P P analysing power at kinetic energy 2.035 GeV fromrun I. The relative and additive systematic errors are +- 0.044 and 0.002.
Experimental results are presented for the pp elastic-scattering single spin observable Aoono=Aooon=AN=P, or the analyzing power, at 19 beam kinetic energies between 1795 and 2235 MeV. The typical c.m. angular range is 60–100°. The measurements were performed at Saturne II with a vertically polarized beam and target (transverse to the beam direction and scattering plane), a magnetic spectrometer and a recoil detector, both instrumented with multiwire proportional chambers, and beam polarimeters.
Measurement values of the P P analysing power at kinetic energy 1.795 GeV. The relative and additive systematic errors are +- 0.106 and 0.003.
Measurement values of the P P analysing power at kinetic energy 1.845 GeV. The relative and additive systematic errors are +- 0.068 and 0.001.
Measurement values of the P P analysing power at kinetic energy 1.935 GeV. The relative and additive systematic errors are +- 0.091 and 0.003.
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