H1 Diffractive Structure Functions Measurement from new data

Abstract

New measurements of the reduced cross section $\sigma_r^{D(3)}$ for the diffractive process $ep \to eXY$ in the kinematic domain $12 \leq Q^2 \leq 90$ GeV$^2$, $0.01 \leq \beta \leq 0.65$ and $\xpom<0.1$ are presented. Data events recorded by the H1 detector during the years 1999--2000 and 2004 have been used, corresponding to a total integrated luminosity of 68 pb$^{-1}$. The measurements are derived in the same range as previous H1 data, namely $M_Y < 1.6$ GeV and $|t| < 1.0$ GeV$^2$. Two different analysis methods, rapidity gap and $M_X$, are used and similar results are obtained in the kinematic domain of overlap. Finally, together with previous data, the diffractive structure function measurements are analysed with a model based on the dipole formulation of diffractive scattering. It is found to give a very good description of the data over the whole kinematic range.