Ball, R.C.
N
Max results
Sort by Reverse order

Showing 2 of 122 results

Measurement of the cross-sections of the reactions e+ e- ---> gamma gamma and e+ e- ---> gamma gamma gamma at LEP

The OPAL collaboration Akwawy, M.Z. ; Alexander, G. ; Allison, J. ; et al.
Phys.Lett.B 257 (1991) 531-540, 1991.
Inspire Record 302587 DOI 10.17182/hepdata.29464

The cross section of the pure QED process e + e − → γγ has been measured using data accumulated during the 1989 and 1990 scans of the Z 0 resonance at LEP. Both the energy dependence and the angular distribution are in good agreement with the QED prediction. Upper limits on the branching ratios of Z 0 → γγ , Z 0 → π 0 γ and Z 0 → ηγ have been set at 1.4×10 −4 , 1.4×10 −4 and 2.0×10 −4 respectively. Lower limits on the cutoff parameters of the modified electron propagator have been found to be Λ + > 117 GeV and Λ − > 110 GeV. The reaction e + e − → γγγ has also been studied and was found to be consistent with the QED prediction. An upper limit on the branching ratio of Z 0 → γγγ has been set at 6.6 × 10 −5 . All the limits are given at 95% confidence level.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


rivet Analysis
Baryon Production in e+ e- Annihilation at PETRA

The JADE collaboration Bartel, W. ; Cords, D. ; Dittmann, P. ; et al.
Phys.Lett.B 104 (1981) 325-329, 1981.
Inspire Record 166363 DOI 10.17182/hepdata.31062

Data on p and Λ production by e + e − -annihilation at CM energies between 30 and 36 GeV are presented. Indication for an angular anticorrelation in events with baryon-antibaryon pairs is seen.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

AVERAGE NUMBER OF ANTIBARYONS PER HADRONIC EVENT. AN EXPONENTIAL SLOPE OF 2.5 GEV*-1 IN E WAS ASSUMED IN EXTRAPOLATING E*D3(SIG)/DP**3 TO ALL MOMENTA.