München 1997 – wissenschaftliches Programm

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T: Teilchenphysik

T 301: Strukturfunktionen III

T 301.4: Vortrag

Mittwoch, 19. März 1997, 16:45–17:00, 225

Determination of the Longitudinal Proton Structure Function F_L at Low x — •Alexander Glazov — DESY-IfH Zeuthen ,15735 Zeuthen, A Glazov

A measurement of the inclusive cross section for the deep-inelastic scattering of positrons off protons at HERA is presented at momentum transfers 8.5 ≤ Q² ≤ 35 GeV² and large inelasticity y = 0.7, i.e. for the Bjorken-x range 0.00013 ≤ x ≤ 0.00055. Using a next-to-leading order QCD fit to the structure function F₂ at lower y values, the contribution of F₂ to the measured cross section at high y is calculated and, by subtraction, the longitudinal structure function F_L is determined for the first time with an average value of F_L=0.52 ± 0.03 (stat) _−0.22 ^+0.25 (syst) at Q²=15.4 GeV² and x=0.000243.