Date

Study of Electron - Positron Collisions at the Highest {PETRA} Energy

The Aachen-DESY-Annecy(LAPP)-MIT-NIKHEF-Beijing collaboration Barber, D.P. ; Becker, U. ; Benda, H. ; et al.
Phys.Lett.B 85 (1979) 463-466, 1979.
Inspire Record 141976 DOI 10.17182/hepdata.27332

We report on the results of the study of e + e − collisions at the highest PETRA energy of √ s = 31.57 GeV, using the 4π sr, electromagnetic and calorimetric detector Mark J. Based on 88 hadron events, and an integrated luminosity of 243 nb −1 we obtain R = σ (e + e − → hadrons)/ σ (e + e − → μ + μ − ) = 4.0 ± 0.5 (statistical) ± 6 (systematic). The R value, the measured thrust distribution and average spherocity show no evidence for the production of new quark flavors.

2 data tables

CORRECTIONS FOR TWO-PHOTON PROCESSES, TAU HEAVY LEPTON PRODUCTION AND INITIAL STATE RADIATIVE CORRECTIONS HAVE BEEN APPLIED.

THRUST DISTRIBUTION (1/N)*DN/DTHRUST AT 31.57 GEV. THESE DATA ARE RATHER DETECTOR DEPENDENT.


Measurements of Elastic Rho and Phi Meson Photoproduction Cross-Sections on Protons from 30 GeV to 180 GeV

Egloff, R.M. ; Davis, P.J. ; Luste, G. ; et al.
Phys.Rev.Lett. 43 (1979) 657, 1979.
Inspire Record 141059 DOI 10.17182/hepdata.20740

The elastic photoproduction cross sections for ρ and ϕ mesons from protons have been measured from 30 to 180 GeV. The energy dependences agree well with predictions made by using vector-meson dominance and an additive quark model. The ρ cross section is approximately constant with energy while the ϕ cross section rises from 0.5 to 0.7 μb with increasing energy.

1 data table

No description provided.


Measurement of Shadowing in Photon - Nucleus Total Cross Sections From 20 to 185 GeV

Caldwell, David O. ; Cumalat, John P. ; Eisner, A.M. ; et al.
Phys.Rev.Lett. 42 (1979) 553, 1979.
Inspire Record 132972 DOI 10.17182/hepdata.20769

We have measured total hadronic photoproduction cross sections on carbon, copper, and lead. Tagged-photon energies ranged from 20 to 185 GeV for copper and from 45 to 82 GeV for carbon and lead. The energy and A dependence of shadowing were computed by comparing these results to the hydrogen cross section as measured nearly simultaneously with the same apparatus. We observed somewhat more shadowing than did most experiments at lower photon energies.

8 data tables

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Measurements of the Photon Total Cross-Section on Protons from 18 GeV to 185 GeV

Caldwell, David O. ; Cumalat, John P. ; Eisner, A.M. ; et al.
Phys.Rev.Lett. 40 (1978) 1222, 1978.
Inspire Record 129172 DOI 10.17182/hepdata.3355

The photon total cross section on protons has been measured with high precision in the Fermilab tagged-photon beam for photon energies from 18 to 185 GeV. The cross section decreases to a broad minimum near 40 GeV, and then rises by about 4 μb over the remainder of the range. A ρ+ω+ϕ vector-dominance model (normalized to low-energy data) falls below the high-energy results by 2 to 6 μb, suggesting a contribution from charm-anticharm states.

2 data tables

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