Measurement of the structure functions F2 and FL at low χ

Abstract

A preliminary measurement of the proton structure function F 2 is presented for momentum transfers squared 2 ≤ Q 2 ≤ 120 GeV 2 and for Bjorken-χ values 3·10 −5 < χ < 0.1. The longitudinal proton structure function F L is determined for low χ values in the range of 3 ≤ Q 2 ≤ 35 GeV 2, using two independent methods. The analysis is based on data collected by the HERA experiment H1 in 1997, with a luminosity of 15 pb −1 for Q 2 > 10 GeV 2 and of 2 pb −1 taken in a dedicated run for Q 2 < 10 GeV 2. This measurement uses in the low Q 2 region the new backward silicon tracker. The accuracy is by nearly a factor of two better than previous results.