Observation of isolated high E($t$) photons in photoproduction at HERA - INSPIRE

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Observation of isolated high E( $t$ ) photons in photoproduction at HERA

ZEUS

Collaboration

•

J. Breitweg
(
- Argonne
)

Jul, 1997

15 pages

Published in:

Phys.Lett.B 413 (1997) 201-216

e-Print:

hep-ex/9708038 [hep-ex]

DOI:

10.1016/S0370-2693(97)01164-7

Report number:

DESY-97-146

Experiments:

DESY-HERA-ZEUS

View in:

ADS Abstract Service

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Abstract:

Events containing an isolated prompt photon with high transverse energy, together with a balancing jet, have been observed for the first time in photoproduction at HERA.The data were taken with the ZEUS detector, in a

\gamma p

centre of mass energy range 120--250 GeV. The fraction of the incoming photon energy participating in the production of the prompt photon and the jet,

x_\gamma

, shows a strong peak near unity, consistent with LO QCD Monte Carlo predictions. In the transverse energy and pseudorapidity range 5\le \eTg < 10 GeV,

-0.7 \le \eta^\gamma < 0.8

, \eTj\ge 5 GeV, and

-1.5\le \eta^{jet}\le 1.8

, with \xgO > 0.8, the measured cross section is

15.3 \pm 3.8 \pm 1.8 pb

, in good agreement with a recent NLO calculation.

Note:

22 pages including 8 figures Report-no: DESY-97-146

positron p: colliding beams
photon: direct production
transverse energy: high
jet: associated production
angular distribution
transverse energy: spectrum
quantum chromodynamics: perturbation theory
ZEUS
experimental results
DESY HERA Stor

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