Measurement of the proton structure function F L (x, Q 2) at low x
Physics Letters Section B Nuclear Elementary Particle and High Energy Physics 665:4 (2008) 139-146
Authors:
FD Aaron, C Alexa, V Andreev, B Antunovic, S Aplin, A Asmone, A Astvatsatourov, A Bacchetta, S Backovic, A Baghdasaryan, P Baranov, E Barrelet, W Bartel, M Beckingham, K Begzsuren, O Behnke, A Belousov, N Berger, JC Bizot, MO Boenig, V Boudry, I Bozovic-Jelisavcic, J Bracinik, G Brandt, M Brinkmann, V Brisson, D Bruncko, A Bunyatyan, G Buschhorn, L Bystritskaya, AJ Campbell, KB Cantun Avila, F Cassol-Brunner, K Cerny, V Cerny, V Chekelian, A Cholewa, JG Contreras, JA Coughlan, G Cozzika, J Cvach, JB Dainton, K Daum, M Deák, Y de Boer, B Delcourt, M Del Degan, J Delvax, A De Roeck, EA De Wolf, C Diaconu, V Dodonov, A Dossanov, A Dubak, G Eckerlin, V Efremenko, S Egli, A Eliseev, E Elsen, S Essenov, A Falkiewicz, PJW Faulkner, L Favart, A Fedotov, R Felst, J Feltesse, J Ferencei, L Finke, M Fleischer, A Fomenko, E Gabathuler, J Gayler, S Ghazaryan, A Glazov, I Glushkov, L Goerlich, M Goettlich, N Gogitidze, M Gouzevitch, C Grab, T Greenshaw, BR Grell, G Grindhammer, S Habib, D Haidt, M Hansson, C Helebrant, RCW Henderson, H Henschel, G Herrera, M Hildebrandt, KH Hiller, D Hoffmann, R Horisberger, A Hovhannisyan, T Hreus, M Jacquet, ME Janssen, X Janssen, V Jemanov
Abstract:
A first measurement is reported of the longitudinal proton structure function F L (x, Q 2) at the ep collider HERA. It is based on inclusive deep inelastic e + p scattering cross section measurements with a positron beam energy of 27.5  GeV and proton beam energies of 920, 575 and 460  GeV. Employing the energy dependence of the cross section, F L is measured in a range of squared four-momentum transfers 12 ≤ Q 2 ≤ 90  GeV 2 and low Bjorken x 0.00024 ≤ x ≤ 0.0036. The F L values agree with higher order QCD calculations based on parton densities obtained using cross section data previously measured at HERA. © 2008 Elsevier B.V. All rights reserved.
