Date

The compact emulsion spectrometer.

Buontempo, S. ; Camilleri, L. ; Catanesi, M.G. ; et al.
Nucl.Instrum.Meth.A 457 (2001) 464-470, 2001.
Inspire Record 531752 DOI 10.17182/hepdata.49938

An emulsion spectrometer has been built and tested with pion beams in a 0.7 T magnetic field. A momentum resolution, Δ P / P =13%±1%, has been obtained for 5 and 10 GeV /c particles.

2 data tables

No description provided.

No description provided.


Production of single W bosons at S**(1/2) = 189-GeV and measurement of W W gamma gauge couplings

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 487 (2000) 229-240, 2000.
Inspire Record 529575 DOI 10.17182/hepdata.49935

Single W boson production in electron-positron collisions is studied with the L3 detector at LEP. The data sample collected at a centre-of-mass energy of \sqrt{s} = 188.7GeV corresponds to an integrated luminosity of 176.4pb^-1. Events with a single energetic lepton or two acoplanar hadronic jets are selected. Within phase-space cuts, the total cross-section is measured to be 0.53 +/- 0.12 +/- 0.03 pb, consistent with the Standard Model expectation. Including our single W boson results obtained at lower \sqrt{s}, the WWgamma gauge couplings kappa_gamma and lambda_gamma are determined to be kappa_gamma = 0.93 +/- 0.16 +/- 0.09 and lambda_gamma = -0.31 +0.68 -0.19 +/- 0.13.

4 data tables

No description provided.

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Measurement of exclusive omega electroproduction at HERA.

The ZEUS collaboration Breitweg, J. ; Chekanov, S. ; Derrick, M. ; et al.
Phys.Lett.B 487 (2000) 273-288, 2000.
Inspire Record 528588 DOI 10.17182/hepdata.46936

The exclusive electroproduction of omega mesons, ep -> e omega p, has been studied in the kinematic range 3<Q^2<20 GeV^2, 40<W<120 GeV and |t|<0.6 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 37.7 pb^{-1}. The omega mesons were identified via the decay omega -> pi^+pi^-pi^0. The exclusive (ep -> e omega p) cross section in the above kinematic region is 0.108 +- 0.014(stat.) +- 0.026(syst.) nb. The reaction ep -> e phi p, phi -> pi^+pi^-pi^0, has also been measured. The cross sections, as well as the cross-section ratios omega/rho and omega/phi, are presented as a function of W and Q^2. Thus, for the first time, the properties of omega electroproduction can be compared to those of rho^0, phi and J/psi electroproduction at high W.

6 data tables

The cross sections for OMEGA and PHI electroproduction.

The corresponding photoproduction cross sections of OMEGA and PHI mesons. The RHO0 data is taken from a previous ZEUS publication (EPJ C6,603).

Ratio of the photoproduction cross sections.

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Measurement of the Z Z cross-section in e+ e- interactions at 183-GeV - 189-GeV.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 497 (2001) 199-213, 2001.
Inspire Record 539640 DOI 10.17182/hepdata.49912

Measurements of on-shell ZZ production are described, using data collected by DELPHI in 1997 and 1998, at centre-of-mass energies sqrt(s) = 182.6 GeV and 188.6 GeV respectively. Results obtained in each of the final states q qbar q qbar, mu+mu- q qbar, e+e- q qbar, nu nubar q qbar, l+l-l+l-, and nu nubar l+l- are presented. The measured cross-sections for on-shell ZZ production via the tree-level doubly-resonant graphs (NC02) are: sigma_{NC02}(182.6 GeV) = 0.38 +- 0.18 (stat) +- 0.04 (syst) pb, sigma_{NC02}(188.6 GeV) = 0.60 +- 0.13 (stat) +- 0.07 (syst) pb. They are consistent with the Standard Model expectations of 0.25 pb and 0.65 pb at each energy.

1 data table

No description provided.


Charged particle multiplicity near mid-rapidity in central Au + Au collisions at S**(1/2) = 56-A/GeV and 130-A/GeV

The PHOBOS collaboration Back, B.B. ; Baker, M.D. ; Barton, D.S. ; et al.
Phys.Rev.Lett. 85 (2000) 3100-3104, 2000.
Inspire Record 530501 DOI 10.17182/hepdata.41732

We present the first measurement of pseudorapidity densities of primary charged particles near mid-rapidity in Au+Au collisions at $\sqrt{s} =$ 56 and 130 AGeV. For the most central collisions, we find the charged particle pseudorapidity density to be $dN/d\eta |_{|\eta|<1} = 408 \pm 12 {(stat)} \pm 30 {(syst)}$ at 56 AGeV and $555 \pm 12 {(stat)} \pm 35 {(syst)}$ at 130 AGeV, values that are higher than any previously observed in nuclear collisions. Compared to proton-antiproton collisions, our data show an increase in the pseudorapidity density per participant by more than 40% at the higher energy.

1 data table

No description provided.


Search for single top production in e+ e- collisions at s**(1/2) = 189-GeV - 202-GeV.

The ALEPH collaboration Barate, R. ; Decamp, D. ; Ghez, Philippe ; et al.
Phys.Lett.B 494 (2000) 33-45, 2000.
Inspire Record 533360 DOI 10.17182/hepdata.49857

Single top production via flavour changing neutral currents in the reactions e + e − → t ̄ c / u is searched for in approximately 411 pb −1 of data collected by ALEPH at centre-of-mass energies in the range between 189 and 202 GeV. In total, 58 events are selected in the data to be compared with 50.3 expected from Standard Model backgrounds. No deviation from the Standard Model expectation is observed. Upper limits at 95% CL on single top production cross sections at s =189 –202 GeV are derived. A model-dependent limit on the sum of branching ratios BR(t→Zc)+BR(t→Zu)<17% is obtained.

1 data table

SIG(C=LEPT) and SIG(C=HADR) are the cross sections upper limits evaluated for leptonic and hadronic decay modes of the W-boson, while SIG(C=COMB) are the values obtained by combining the leptonic and hadronic W-boson decay channels. All cross sections values are obtained under assumption of BR(TQ --> W+ BQ) = 100 %.


Search for anomalous couplings in the Higgs sector at LEP

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 489 (2000) 102-114, 2000.
Inspire Record 531571 DOI 10.17182/hepdata.49878

We search for a Higgs particle with anomalous couplings in the e+e- -> H gamma, e+e- -> HZ and e+e- -> He+e- processes with the L3 detector at LEP. We explore the mass range 70GeV &lt; m_H &lt; 170GeV using 176pb^-1 of integrated luminosity at a center-of-mass energy of \sqrt{s} = 189GeV. The Higgs decays H -> bb, H -> gamma gamma and H -> Z gamma are considered in the analysis. No evidence for anomalous Higgs production is found. This is interpreted in terms of limits on the anomalous couplings d, d_B, Delta g_1^Z and Delta kappa_gamma. Limits on the Gamma(H -> gamma gamma) and Gamma(H -> Z gamma) partial widths in the explored Higgs mass range are also obtained.

3 data tables

The cross section times BR(HIGGS --> 2GAMMA).

The cross section times BR(HIGGS --> BQ BQBAR).

The cross section times BR(HIGGS --> Z GAMMA).


Determination of the e+ e- --> gamma gamma (gamma) cross-section at centre-of-mass energies ranging from 189-GeV to 202-GeV.

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adye, T. ; et al.
Phys.Lett.B 491 (2000) 67-80, 2000.
Inspire Record 534257 DOI 10.17182/hepdata.49880

A test of the QED process e+e- -> gamma gamma (gamma) is reported. The data analysed were collected with the DELPHI detector in 1998 and 1999 at the highest energies achieved at LEP, reaching 202 GeV in the centre-of-mass. The total integrated luminosity amounts to 375.7 pb^{-1}. The differential and total cross-sections for the process e+e- -> gamma gamma were measured, and found to be in agreement with the QED prediction. 95% Confidence Level (C.L.) lower limits on the QED cut-off parameters of Lambda+ > 330 GeV and Lambda- > 320 GeV were derived. A 95% C.L. lower bound on the mass of an excited electron of 311 GeV/c^2 (for lambda_gamma = 1) was obtained. s-channel virtual graviton exchange was searched for, resulting in 95% C.L. lower limits on the string mass scale, M_S: M_S > 713 GeV/c^2 (lambda = 1) and M_S > 691 GeV/c^2 (lambda = -1).

7 data tables

No description provided.

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W+ W- production cross section and W branching fractions in e+ e- collisions at 189-GeV.

The OPAL collaboration Abbiendi, G. ; Ackerstaff, K. ; Ainsley, C. ; et al.
Phys.Lett.B 493 (2000) 249-265, 2000.
Inspire Record 533110 DOI 10.17182/hepdata.49910

From a data sample of 183 pb^-1 recorded at a center-of-mass energy of roots = 189 GeV with the OPAL detector at LEP, 3068 W-pair candidate events are selected. Assuming Standard Model W boson decay branching fractions, the W-pair production cross section is measured to be sigmaWW = 16.30 +- 0.34(stat.) +- 0.18(syst.) pb. When combined with previous OPAL measurements, the W boson branching fraction to hadrons is determined to be 68.32 +- 0.61(stat.) +- 0.28(syst.) % assuming lepton universality. These results are consistent with Standard Model expectations.

2 data tables

Total W+ W- pair production cross section.

Cross sections for the individual decay modes of the W+ W-.


Measurement of the W pair production cross-section and W decay branching fractions in e+ e- interactions at S**(1/2) = 189-GeV

The L3 collaboration Acciarri, M. ; Achard, P. ; Adriani, O. ; et al.
Phys.Lett.B 496 (2000) 19-33, 2000.
Inspire Record 531766 DOI 10.17182/hepdata.49879

The data collected by the L3 experiment at LEP at a centre-of-mass energy of 188.6 GeV are used to measure the W-pair production cross section and the W-boson decay branching fractions. These data correspond to an integrated luminosity of 176.8pb^-1. The total cross section for W-pair production, combining all final states, is measured to be sigma_WW = 16.24 +/- 0.37(stat.) +/- 0.22(syst.) pb. Including our data collected at lower centre-of-mass energies, the hadronic branching fraction of the W-boson is determined to be B(W ->qq) = [68.20 +/- 0.68 (stat.) +/- 0.33 (syst.) ] %. The results agree with the Standard Model predictions.

2 data tables

Quoted cross sections with W-boson decays (i.e. W +- < ... >) mean the cross sections times the corresponding branching ratios.

VCS is the CKM matrix element.