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Tests of QED at LEP energies using e+ e- --> gamma gamma (gamma) and e+ e- --> lepton+ lepton- gamma gamma

The L3 collaboration Acciarri, M. ; Adam, A. ; Adriani, O. ; et al.

Phys.Lett.B 353 (1995) 136-144, 1995.

Inspire Record 394354 DOI 10.17182/hepdata.47938

Total and differential cross sections for the process e + e − → γγ ( γ ), and the total cross section for the process e + e − → γγγ , are measured at energies around 91 GeV using the data collected with the L3 detector from 1991 to 1993. We set lower limits, at 95% CL, on a contact interaction energy scale parameter Λ > 602 GeV, on the mass of an excited electron m e ∗ >146 GeV and on the QED cut-off parameters Λ + > 149 GeV and Λ _ > 143 GeV. Upper limits are also set o branching fractions of Z decaying into γγ , π ° and ηγ of 5.2 × 10 −5 , 5.2 × 10 −5 and 7.6 × 10 −5 respectively. The reactions e + e − → ℓ + ℓ − nγ (ℓ = e , μ , τ ) are studied using the data collected from 1990 to 1994. The data are consistent with the QED expectations.

3 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

A Test of quantum electrodynamics in the reaction e+ e- ---> gamma gamma (gamma)

The L3 collaboration Adriani, O. ; Aguilar-Benitez, M. ; Ahlen, S. ; et al.

Phys.Lett.B 288 (1992) 404-411, 1992.

Inspire Record 336900 DOI 10.17182/hepdata.29221

We have measured the total and differential cross sections of the reaction e + e − → γγ ( γ ) at center-of-mass energies around 91 GeV, with an integrated luminosity of 14.2 pb −1 . The results are in good agreement with QED predictions. We set lower limits, at 95% confidence level, on the QED cutoff parameters of Λ + > 139 GeV, Λ − > 108 GeV and on the mass of an excited electron of m e∗ > 127 GeV . We searched for Z 0 rare decays with photonic signitures in the final state. Upper limits, at 95% confidence level, for branching ratio of Z 0 decaying into π 0 γ / γγ , νγ and γγγ are 1.2 × 10 −4 , 1.8 × 10 −4 , 3.3 × 10 −5 respectively.

3 data tables

Table 1

Measured cross section for the 1991 data.

Table 2

Measured cross section for the 1990 data.

Table 3

Measured differential cross sections of combined 1990 and 1991 data.

MEASUREMENT OF THE DIFFERENTIAL CROSS-SECTIONS FOR THE PI+ D ---> P P REACTION AT PION ENERGIES OF 280-MEV, 300-MEV, 330-MEV, 357-MEV, 390-MEV, 420-MEV AND 450-MEV

Borkovsky, M.Ya. ; Gaditsky, V.G. ; Gavrilov, G.E. ; et al.

J.Phys.G 11 (1985) 69-83, 1985.

Inspire Record 215606 DOI 10.17182/hepdata.38587

Differential cross sections for the process pi +d to pp at seven energies in the region Tpi =280-450 MeV and in the angular range theta * approximately=4-90 degrees have been measured on the LNPI synchrocyclotron. The results include 94 new data points. The measurements have been carried out using a ten-channel hodoscope set-up. Statistical errors are between 2.5% and 7.8% depending on the scattering angle and Tpi . The data obtained indicate that there is an essential contribution from the partial wave with orbital angular momentum l=3 over the whole energy range considered. The authors also observe a noticeable contribution from the l=4 partial wave to the differential cross sections of the pi +d to pp reaction from Tpi >or=357 MeV. The total cross sections for the process pi +d to pp are also presented.

9 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.