Deep Inelastic Positron-Proton Scattering in the High-Momentum-Transfer Regime of HERA

Deep Inelastic Positron-Proton Scattering in the High-Momentum-Transfer Regime of HERA

Author: Ulrich F. Katz

Publisher: Springer

Published: 2003-07-01

Total Pages: 243

ISBN-13: 354045019X

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About three decades after the first experiments on deep inelastic lepton hadron scattering began to investigate the structure of hadrons, the history of this fruitful field of particle physics continues in the broad spectrum of research performed at the electron and positron proton collider HERA at DESY, where the multipurpose detectors ZEUS and H1 access ep scattering at a center of mass energy of 300 GeV and explore as yet uncharted kinematic realms of deep inelastic scattering. After the first years of data taking at HERA, each of the experiments has collected a total of roughly 40 pb 1 of e+p data, yielding sensitivity to deep inelastic e+p interactions at high four momentum transfers, Q2, where typi cal cross sections drop into the subpicobarn regime. This kinematic domain is characterized by electroweak unification, manifesting itself most markedly in the neutral and charged current cross sections, which approach an equal order of magnitude as Q2 rises above the square of the W and Z masses. Consequently, HERA allows, for the first time, studies of both types of pro cesses simultaneously with the same initial state conditions and in the same detector, and thus we can investigate the interplay of electroweak and strong forces governing the respective cross sections.


Experimental Study of Initial State Radiative Events at HERA and a Measurement of the Proton Longitudinal Structure Function

Experimental Study of Initial State Radiative Events at HERA and a Measurement of the Proton Longitudinal Structure Function

Author: Jason Schwartz

Publisher:

Published: 2011

Total Pages:

ISBN-13:

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A first measurement of the radiative contribution to deep inelastic electron-proton scattering has been performed with the ZEUS detector at HERA. Results show consistency with predictions made by the HERACLES Monte Carlo program. New calibration and simulation of the far luminosity measurement system, including a photon calorimeter and two aerogel Cherenkov detectors, have been implemented. Both calibration and simulation were applied to tag photons produced in the initial state radiative process. These tagged events were used to perform measurements of the deep inelastic ep scattering reduced cross section down to momentum transfer squared, Q2 = 3.0 GeV2, a region normally inaccessible to ZEUS. A determination of the radiative contribution to deep inelastic scattering has aided in the measurement of the structure functions F2 and FL, which were simultaneously extracted in the kinematic region 8.0 GeV2


Positron-proton Scattering

Positron-proton Scattering

Author: Andrew Arnold Browman

Publisher:

Published: 1964

Total Pages: 318

ISBN-13:

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The importance of two-photon exchange in elastic electron-proton scattering was investigated by measuring the ratio of positron-proton to electron-proton scattering. Four momentum transfers as large as 0.756 (BeV/c) to the 2nd power (19.5 F to the -2nd power) were used. The data indicate that two-photon effects are 4.0 = 1.5% larger than those predicted by the radiative corrections at the highest momentum transfers attained in these experiments. The two-photon corrections predicted, using a static charge distribution, fit the data well at lower momentum transfers and forward angles but appear to be small at higher momentum transfers and backward angles. (Author).