HEPData Search

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Compton scattering of quasi-real virtual photons at LEP.

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.

Phys.Lett.B 616 (2005) 145-158, 2005.

Inspire Record 679959 DOI 10.17182/hepdata.48828

Compton scattering of quasi-real virtual photons, gamma e+- -> gamma e+-, is studied with 0.6fb-1 of data collected by the L3 detector at the LEP e+e- collider at centre-of-mass energies root(s')=189-209GeV. About 4500 events produced by the interaction of virtual photons emitted by e+- of one beam with e-+ of the opposite beam are collected for effective centre-of-mass energies of the photon-electron and photon-positron systems in the range from root(s')= 35GeV up to root(s')=175GeV, the highest energy at which Compton scattering was ever probed. The cross sections of the gamma e+- -> gamma e+- process as a function of root(s') and of the rest-frame scattering angle are measured, combined with previous L3 measurements down to root(s')~20GeV, and found to agree with the QED expectations.

3 data tables

Table 1

Measured Compton scattering cross section as a function of the effective centre of mass of the photon-electron system. THETA(RF=CM) is the electron rest frame scattering angle.

Table 2

The measured angular distribution over the photon-electron centre of mass energy range 35 to 175 GeV.

Table 3

The measured Compton scattering cross section using the full data sample including the lower energy data from Acciarri et al. PL B439(1998)183. Errors are combined statistics and systematics.

Measurement of the cross section of W-boson pair production at LEP.

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.

Phys.Lett.B 600 (2004) 22-40, 2004.

Inspire Record 658254 DOI 10.17182/hepdata.48792

The cross section of W-boson pair-production is measured with the L3 detector at LEP. In a data sample corresponding to a total luminosity of 629.4/pb, collected at centre-of-mass energies ranging from 189 to 209 GeV, 9834 four-fermion events with W bosons decaying into hadrons or leptons are selected. The total cross section is measured with a precision of 1.4 % and agrees with the Standard Model expectation. Assuming charged-lepton universality, the branching fraction for hadronic W-boson decays is measured to be: Br(W-->hadrons) = 67.50 +- 0.42 (stat.) +- 0.30(syst.) %, in agreement with the Standard Model. Differential cross sections as a function of the W- production angle are also measured for the semi-leptonic channels qqev and qqmv.

11 data tables

Table 1

Measured cross section for the process E+ E- --> LEPTON NU LEPTON NU.

Table 2

Measured cross section for the process E+ E- --> QUARK QUARKBAR ELECTRON NEUTRINO.

Table 3

Measured cross section for the process E+ E- --> QUARK QUARKBAR MUON NEUTRINO.

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Proton anti-proton pair production in two photon collisions at LEP

The L3 collaboration Achard, P. ; Adriani, O. ; Aguilar-Benitez, M. ; et al.

Phys.Lett.B 571 (2003) 11-20, 2003.

Inspire Record 620433 DOI 10.17182/hepdata.48883

The reaction e^+e^- -> e^+e^- proton antiproton is studied with the L3 detector at LEP. The analysis is based on data collected at e^+e^- center-of-mass energies from 183 GeV to 209 GeV, corresponding to an integrated luminosity of 667 pb^-1. The gamma gamma -> proton antiproton differential cross section is measured in the range of the two-photon center-of-mass energy from 2.1 GeV to 4.5 GeV. The results are compared to the predictions of the three-quark and quark-diquark models.

4 data tables

Table 1

Total cross section for P PBAR production at a mean centre-of-mass energy of 197 GeV.

Table 2

The cross section as a function of W for ABS(COS(THETA)) < 0.6.

Table 3

The differential cross section as a function of COS(THETA*) for three W ranges.

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