Date

Measurement of e+ e- ---> e+ e- and e+ e- ---> mu+ mu- at SPEAR

Augustin, J.E. ; Boyarski, A. ; Breidenbach, Martin ; et al.
Phys.Rev.Lett. 34 (1975) 233, 1975.
Inspire Record 91755 DOI 10.17182/hepdata.21210

The reactions e+e−→e+e− and e+e−→μ+μ− have been measured at center-of-mass energies 3.0, 3.8, and 4.8 GeV and production angles of 50°<θ<130° over all azimuthal angles. Agreement with quantum electrodynamics is excellent. New limits for cutoff parameters in quantum-electrodynamic-breakdown models are given.

2 data tables

No description provided.

No description provided.


Discovery of a Narrow Resonance in $e^+ e^-$ Annihilation

The SLAC-SP-017 collaboration Augustin, J.E. ; Boyarski, A. ; Breidenbach, Martin ; et al.
Phys.Rev.Lett. 33 (1974) 1406-1408, 1974.
Inspire Record 91761 DOI 10.17182/hepdata.21247

We have observed a very sharp peak in the cross section for e+e−→hadrons, e+e−, and possibly μ+μ− at a center-of-mass energy of 3.105±0.003 GeV. The upper limit to the full width at half-maximum is 1.3 MeV.

1 data table

No description provided.


The Discovery of a Second Narrow Resonance in e+ e- Annihilation

Abrams, G.S. ; Briggs, D. ; Chinowsky, William ; et al.
Phys.Rev.Lett. 33 (1974) 1453-1455, 1976.
Inspire Record 91611 DOI 10.17182/hepdata.21287

We have observed a second sharp peak in the cross section for e+e−→hadrons at a center-of-mass energy of 3.695±0.004 GeV. The upper limit of the full width at half-maximum is 2.7 MeV.

1 data table

No description provided.


Hadron Production by electron positron annihilation at 4-GeV center-of-mass energy

Litke, A. ; Hanson, G. ; Hofmann, A. ; et al.
Phys.Rev.Lett. 30 (1973) 1189-1192, 1973.
Inspire Record 85252 DOI 10.17182/hepdata.21416

We have measured the total cross section for electron-positron annihilation into three or more hadrons, with at least two charged particles in the final state. The measurement was made at a center-of-mass energy of 4 GeV with a 2π−sr nonmagnetic detector. With 88 events detected, we obtain a model-independent lower limit on the hadron production cross section of 9.6 ± 1.4 nb; a calculation of detection efficiency based on invariant phase-space production of pions leads to a total cross section of 26 ± 6 nb. This cross section is 4.7 ± 1.1 times the theoretical total cross section for e+e−→μ+μ−. The average charged multiplicity is n¯=4.2±0.6.

1 data table

No description provided.