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arXiv · hep-ex/9504003

Observation of the beam-size effect at HERA

Krzysztof Piotrzkowski
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Abstract

A precise measurement of the spectrum of the photons from $ep$ bremsstrahlung with the ZEUS luminosity monitor at HERA is reported. The measurement shows a reduced rate compared to the Bethe-Heitler spectrum for photon energies below 5~GeV. This suppression, called the beam-size effect, is explained by the finite transverse size of the beam overlap relative to the typical impact parameter in the process of $ep$ bremsstrahlung at HERA energies.

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Krzysztof Piotrzkowski. 1995-04-11. Observation of the beam-size effect at HERA. https://doi.org/10.1007/bf01553983

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