264 research outputs found
DESY 04--083 ISSN 0918--9833 Measurement of the Proton Structure Function F 2
No full textThe proton structure function F 2 (x, Q ) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA.QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q , down to 0.5 GeV and Bjorken x up to #0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton-nucleon scattering experiments. Submitted to Physics Letters B A. Aktas , V. Andreev , T. Anthonis , A. Asmone , A. Babaev , S. Backovic , J. Bahr P. Baranov , E. Barrelet , W. Bartel , S. Baumgartner , J. Becker , M. Beckingham O. Behnke , O. Behrendt , A. Belousov , Ch. Berger , N. Berger , T. Berndt , J.C. Bizot J. Bohme , M.-O. Boenig , V. Boudry , J. Bracinik , V. Brisson , H.-B. Broker D.P. Brown , D. Bruncko , F.W. Busser , A. Bunyatyan 12,36 , G. Buschhorn L. Bystritskaya , A.J. Campbell , S. Caron , F. Cassol-Brunner , K. Cerny , V. Chekelian C. Collard , J.G. Contreras , Y.R. Coppens , J.A. Coughlan , B.E. Cox , G. Cozzika J. Cvach , J.B. Dainton , W.D. Dau , K. Daum 35,41 , B. Delcourt , R. Demirchyan A. De Roeck 10,44 , K. Desch , E.A. De Wolf , C. Diaconu , J. Dingfelder , V. Dodonov A. Dubak , C. Duprel , G. Eckerlin , V. Efremenko , S. Egli , R. Eichler , F. Eisele M. Ellerbrock , E. Elsen , M. Erdmann 10,42 , W. Erdmann , P.J.W. Faulkner , L. Favart A. Fedotov , R. Felst , J. Ferencei , M. Fleischer , P. Fleischmann , Y.H. Fleming G. Flucke , G. Flugge , A. Fomenko , I. Foresti , J. Formanek , G. Franke , G. Frising E. Gabathuler , K. Gabath..
QED radiative corrections to Virtual Compton Scattering
No full textThe QED radiative corrections to virtual Compton scattering (reaction ep-->ep gamma) are calculated to first order in alpha(em)=e(2)/4 pi. A detailed study is presented for the one-loop virtual corrections and for the first order soft-photon emission contributions. Furthermore, a full numerical calculation is given for the radiative tail, corresponding to photon emission processes, where the photon energy is not very small compared with the lepton momenta. We compare our results with existing works on elastic electron-proton scattering, and show for the ep-->ep gamma reaction how the observables are modified due to these first order QED radiative corrections. We show results for both unpolarized and polarized observables of virtual Compton scattering in the low energy region (where one is sensitive to the generalized polarizabilities of the nucleon), as well as for the deeply virtual Compton scattering
QED radiative corrections to Virtual Compton Scattering
No full textThe QED radiative corrections to virtual Compton scattering (reaction ep-->ep gamma) are calculated to first order in alpha(em)=e(2)/4 pi. A detailed study is presented for the one-loop virtual corrections and for the first order soft-photon emission contributions. Furthermore, a full numerical calculation is given for the radiative tail, corresponding to photon emission processes, where the photon energy is not very small compared with the lepton momenta. We compare our results with existing works on elastic electron-proton scattering, and show for the ep-->ep gamma reaction how the observables are modified due to these first order QED radiative corrections. We show results for both unpolarized and polarized observables of virtual Compton scattering in the low energy region (where one is sensitive to the generalized polarizabilities of the nucleon), as well as for the deeply virtual Compton scattering
Measurement of the proton structure function F2 at low Q2 in QED compton scattering at HERA.
No full textThe proton structure function F2(x,Q2) is measured in inelastic QED Compton scattering using data collected with the H1 detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon, Q2, down to 0.5 GeV2, and Bjorken x up to 0.06, a region which has not been covered previously by inclusive measurements at HERA. The results are in agreement with the measurements from fixed target lepton–nucleon scattering experiments
High-rate electron detectors to study Compton scattering in non-perturbative QED
No full textResearch in non-perturbative QED in strong-field backgrounds has gained
interest in recent years, due to advances in high-intensity laser technologies
that make extreme fields accessible in the laboratory. One key signature of
strong-field QED is non-linear Compton scattering in collisions between a
relativistic electron beam and a high-intensity laser pulse. In the vicinity of
strong fields, the electron gains a larger effective mass, which leads to a
laser-intensity-dependent shift of the kinematic Compton edge and the
appearance of higher-order harmonics in the energy spectrum. One of the
challenges of measuring the Compton energy spectrum in laser-electron-beam
collisions is the enormous flux of outgoing Compton-scattered electrons and
photons, ranging from to particles per collision. We present a
combined detector system for high-rate Compton electron detection in the
context of the planned LUXE experiment, consisting of a spatially segmented
gas-filled Cherenkov detector and a scintillator screen imaged by an optical
camera system. The detectors are placed in a forward dipole spectrometer to
resolve the electron energy spectrum. Finally, we discuss techniques to
reconstruct the non-linear Compton electron energy spectrum from the high-rate
electron detection system and to extract the features of non-perturbative QED
from the spectrum
High-rate electron detectors to study Compton scattering in non-perturbative QED
No full textResearch in non-perturbative QED in strong-field backgrounds has gained interest in recent years, due to advances in high-intensity laser technologies that make extreme fields accessible in the laboratory. One key signature of strong-field QED is non-linear Compton scattering in collisions between a relativistic electron beam and a high-intensity laser pulse. In the vicinity of strong fields, the electron gains a larger effective mass, which leads to a laser-intensity-dependent shift of the kinematic Compton edge and the appearance of higher-order harmonics in the energy spectrum. One of the challenges of measuring the Compton energy spectrum in laser-electron-beam collisions is the enormous flux of outgoing Compton-scattered electrons and photons, ranging from to particles per collision. We present a combined detector system for high-rate Compton electron detection in the context of the planned LUXE experiment, consisting of a spatially segmented gas-filled Cherenkov detector and a scintillator screen imaged by an optical camera system. The detectors are placed in a forward dipole spectrometer to resolve the electron energy spectrum. Finally, we discuss techniques to reconstruct the non-linear Compton electron energy spectrum from the high-rate electron detection system and to extract the features of non-perturbative QED from the spectrum
High-rate electron detectors to study Compton scattering in non-perturbative QED
No full textResearch in non-perturbative QED in strong-field backgrounds has gained interest in recent years, due to advances in high-intensity laser technologies that make extreme fields accessible in the laboratory. One key signature of strong-field QED is non-linear Compton scattering in collisions between a relativistic electron beam and a high-intensity laser pulse. In the vicinity of strong fields, the electron gains a larger effective mass, which leads to a laser-intensity-dependent shift of the kinematic Compton edge and the appearance of higher-order harmonics in the energy spectrum. One of the challenges of measuring the Compton energyspectrum in laser-electron-beam collisions is the enormous flux of outgoing Compton-scattered electrons and photons, ranging from to particles per collision. We present a combined detector system for high-rate Compton electron detection in the context of the planned LUXE experiment, consisting of a spatially segmented gas-filled Cherenkov detector and a Scintillator screen imaged by an optical camera system. The detectors are placed in a forward dipole spectrometer to resolve the electron energy spectrum. Finally, we discuss techniques to reconstruct the non-linear Compton electron energy spectrum from the high-rate electron detection system and to extract the features of non-perturbative QED from the spectrum
A study of quasi-real QED Compton events at HERA
No full textAn experimental study of the QED Compton process using the data recorded by the HI detector at the electron-proton collider HERA in 1994 and 1995 is presented. Using the samples of these events the backward electromagnetic calorimeters, i.e. lead scintillator sampling calorimeter BEMC in 1994 and the one of the spaghetti lead-fibre type SPACAL in 1995 were studied in terms of the absolute energy scale, response linearity, relative position to the beam line, and the corresponding backward tracking detector, i.e. backward proportional chamber (BPC) in 1994 and backward drift chamber (BDC) in 1995. The efficiencies of the BPC and BDC are determined, the probability of the #gamma#-conversion in front of the BPC-BEMC and BDC-SPACAL systems are evaluated and the amount of the dead material in that region is estimated. The selected samples of the QED Compton events are employed to make an independent luminosity measurement. The role of the results of the QED Compton events analysis in the physics analysis such as the proton structure function F_2 measurement is discussed. (orig.)Available from TIB Hannover: RR 8919(1999-006) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Determination of the integrated luminosity at HERA using elastic QED Compton events
No full textA measurement of the integrated luminosity at the ep collider HERA is presented, exploiting the elastic QED Compton process ep→eγp. The electron and the photon are detected in the backward calorimeter of the H1 experiment. The integrated luminosity of the data recorded in 2003 to 2007 is determined with a precision of 2. 3 %. The measurement is found to be compatible with the corresponding result obtained using the Bethe-Heitler process. © 2012 The Author(s).0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Measurement of the Proton Structure Function F_2 at Low Q^2 in QED Compton Scattering at HERA
No full textThe proton structure function F2(x,Q2) is measured in inelastic QED Compton scattering using data collected with the H1detector at HERA. QED Compton events are used to access the kinematic range of very low virtualities of the exchanged photon,Q2, down to 0.5 GeV2, and Bjorken x up to ¡« 0.06, a region which has not been covered previously by inclusive measurementsat HERA. The results are in agreement with the measurements from fixed target lepton–nucleon scattering experiments
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