Matis, H.S.
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Production of Single W Bosons at LEP

The L3 collaboration Acciarri, M. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 403 (1997) 168-176, 1997.
Inspire Record 441927 DOI 10.17182/hepdata.47358

We report on the observation of single W boson production in a data sample collected by the L3 detector at LEP2. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The cross-section is measured to be 0.61 −0.33 +0.43 ± 0.05 pb at the centre of mass energy s = 172 GeV , consistent with the Standard Model expectation. From this measurement the following limits on the anomalo γWW gauge couplingsare derived at 95% CL: −3.6 < Δκ γ < 1.5 and −3.6 < λ γ < 3.6.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Measurement of diffractive dijet production at the Tevatron

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 79 (1997) 2636-2641, 1997.
Inspire Record 441461 DOI 10.17182/hepdata.42208

We report the observation and measurement of the rate of diffractive dijet production at the Fermilab Tevatron p¯p collider at s=1.8TeV. In events with two jets of ET>20GeV, 1.8<|η|<3.5, and η1η2>0, we find that the diffractive to nondiffractive production ratio is RJJ=[0.75±0.05(stat)±0.09(syst)]%. By comparing this result, in combination with our measured rate for diffractive W boson production reported previously, with predictions based on a hard partonic pomeron structure, we determine the pomeron gluon fraction to be fg=0.7±0.2.

1 data table
Table 1

No description provided.


First observation of the all hadronic decay of t anti-t pairs

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 79 (1997) 1992-1997, 1997.
Inspire Record 441462 DOI 10.17182/hepdata.42211

We present the first observation of the all hadronic decay of tt¯ pairs. The analysis is performed using 109pb−1 of pp¯ collisions at s=1.8TeV collected with the Collider Detector at Fermilab. We observe an excess of events with five or more jets, including one or two b jets, relative to background expectations. Based on this excess we evaluate the production cross section to be in agreement with previous results. We measure the top mass to be 186±10±12GeV/c2.

2 data tables
Table 1

The cross section is given in the paper at a TQ mass of 175 GeV. The values at TQ mass = (175 +- 10) GeV is evaluated as +20% and -12% as given in the paper. The statistical error has also been scaled.

Table 2

The measured value of the top mass.


Pair production of W bosons in e+ e- interactions at s**(1/2) = 161-GeV

The L3 collaboration Acciarri, M. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.
Phys.Lett.B 398 (1997) 223-238, 1997.
Inspire Record 440408 DOI 10.17182/hepdata.47356

We report on the measurement of W-boson pair-production with the L3 detector at LEP at a centre-of-mass energy of 161.34 GeV. In a data sample corresponding to a total luminosity of 11 pb −1 , we select four-fermion events with high invariant masses of pairs of hadronic jets or leptons. Combining all final states, the measured total cross section for W-pair production is: sigma WW = 2.89 −0.70 +0.81 (stat.) ± 0.14 (syst.) pb. Within the Standard Model, this corresponds to a mass of the W boson of: M W = 80.80 −0.42 +0.48 (exp.) ± 0.03 (LEP) GeV. Limits on anomalous triple-vector-boson couplings are derived.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Study of the Z Z gamma and Z gamma gamma couplings in Z (neutrino neutrino) gamma production

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.Lett. 78 (1997) 3640-3645, 1997.
Inspire Record 440634 DOI 10.17182/hepdata.42214

We have measured the ZZ-gamma and Z-gamma-gamma couplings by studying p-bar p -> (missing ET) gamma + X events at sqrt(s)=1.8 TeV with the D0 detector at the Fermilab Tevatron Collider. This first study of hadronic Z-gamma production in the neutrino decay channel gives the most stringent limits on anomalous couplings available. A fit to the transverse energy spectrum of the photon in the candidate event sample, based on a data set corresponding to an integrated luminosity of 13.1 pb~(-1), yields 95% CL limits on the anomalous CP-conserving ZZ-gamma couplings of |h~Z_(30)|<0.9, |h~Z_(40)|<0.21, for a form-factor scale Lambda = 500 GeV. Combining these results with our previous measurement using Z -> ee and mu-mu yields the limits:|h~Z_(30)|<0.8, |h~Z_(40)|<0.19 (Lambda = 500 GeV) and |h~Z_(30)|<0.4, |h~Z_(40)|<0.06 (Lambda = 750 GeV).

1 data table
Table 1

CONST(NAME=SCALE) is the model parameter, used in the modification of the couplings as follows: h = hi0/(1 + M(gamma Z)**2/CONT(NAME=SCALE)**2)**n. See article for details.. The data with Z --> lepton+ lepton- is taken from S.Abachi, PRL 75, 1028.


rivet Analysis
J / psi and psi (2S) production in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 79 (1997) 572-577, 1997.
Inspire Record 440101 DOI 10.17182/hepdata.42223

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.

5 data tables
Table 1

Integrated cross sections.

Table 2

Differential cross section times branching ratio for J/PSI's originating from b hadron decays.

Table 3

Differential cross section times branching ratio for PSI(2S) originating from b hadron decays.

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rivet Analysis
Production of J / psi mesons from chi(c) meson decays in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 79 (1997) 578-583, 1997.
Inspire Record 440446 DOI 10.17182/hepdata.42231

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.

4 data tables
Table 1

Fraction of J/PSI mesons from CHI/C decays, excluding the the contributions from b-hadron decay.

Table 2

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.

Table 3

Differential cross section for J/PSI's produced in CHI/C decays.

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Differential cross sections of D*-+ photoproduction in e p collisions at HERA.

The ZEUS collaboration Breitweg, J. ; Derrick, M. ; Krakauer, D. ; et al.
Phys.Lett.B 401 (1997) 192-206, 1997.
Inspire Record 441088 DOI 10.17182/hepdata.44632

Inclusive photoproduction of $\dspm$ in ep collisions at HERA has been measured with the ZEUS detector for photon-proton centre of mass energies in the range \linebreak \wrang and photon virtuality Q~2 < 4 \g2. The cross section $\sigma_{ep \to \ds X} $ integrated over the kinematic region \ptrangand \etarang is {\xsecs}. Differential cross sections as functions of $p_{\perp}~{\ds}$, $\eta~{\ds}$ and W are given. The data are compared with two next-to-leading order perturbative QCD predictions. For a calculation using a massive charm scheme the predicted cross sections are smaller than the measured ones. A recent calculation using a massless charm scheme is in agreement with the data.

6 data tables
Table 1

Data from the (Kpi)pi channel.

Table 2

Data from the (Kpipipi)pi channel.

Table 3

Data from the (Kpi)pi channel.

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Observation of diffractive W boson production at the Tevatron

The CDF collaboration Abe, F. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 78 (1997) 2698-2703, 1997.
Inspire Record 440095 DOI 10.17182/hepdata.42230

We report the first observation of diffractively produced W bosons. In a sample of W -> e nu events produced in p-barp collisions at sqrt{s}=1.8 TeV, we find an excess of events with a forward rapidity gap, which is attributed to diffraction. The probability that this excess is consistent with non-diffractive production is 1.1 10^{-4} (3.8 sigma). The relatively low fraction of W+Jet events observed within this excess implies that mainly quarks from the pomeron, which mediates diffraction, participate in W production. The diffractive to non-diffractive W production ratio is found to be R_W=(1.15 +/- 0.55)%.

1 data table
Table 1

No description provided.


Search for top squark pair production in the dielectron channel

The D0 collaboration Abachi, S. ; Abbott, B. ; Abolins, M. ; et al.
Phys.Rev.D 57 (1998) 589-593, 1998.
Inspire Record 427311 DOI 10.17182/hepdata.41662

This report describes the first search for top squark pair production in the channel stop_1 stopbar_1 -> b bbar chargino_1 chargino_1 -> ee+jets+MEt using 74.9 +- 8.9 pb~-1 of data collected using the D0 detector. A 95% confidence level upper limit on sigma*B is presented. The limit is above the theoretical expectation for sigma*B for this process, but does show the sensitivity of the current D0 data set to a particular topology for new physics.

1 data table
Table 1

Data are extracted from the figure. Sigma*Br.