Extraction of the Pomeron Trajectory from a Global Fit to Exclusive $\ddot{I}{}^0$ Meson Photoproduction Data

Abstract

Based on data on elastic $\ddot{I}{}^0$ photoproduction from the H1, Omega and ZEUS collaborations, a fit has been performed to extract the value $\hat{I}{\pm }_P(t)$ of the pomeron trajectory at fixed values of t from the W dependence of the differential ${\hat{I}}^{3}p$ cross section $d\ddot{I}{ƒ}_{{\hat{I}}^{3}p}(W)/dt$. The data used in the fit cover the range of $8.3\le W\le 94GeV$ in ${\hat{I}}^{3}p$ centre-of-mass energy and $0.01\le |t|\le 0.95Ge{V}^2$ in momentum transfer. A linear fit to the resulting values of $\hat{I}{\pm }_P(t)$ yields $\hat{I}{\pm }_{P,0}=1.0871\pm 0.0026(stat.)\pm 0.0030(syst.)$ for the intercept and $\hat{I}{\pm }_P^{\prime }=0.126\pm 0.013(stat.)\pm 0.012(syst.)Ge{V}^{-2}$ for the slope of the pomeron trajectory. The data are also compatible with the Donnachie-Landshoff trajectory $\hat{I}{\pm }_P(t)=1.0808+0.25Ge{V}^{-2}\cdot t$ at low values $|t|\lesssim 0.3Ge{V}^2$ and with a constant value of $\hat{I}{\pm }_P(t)$ at larger values of $|t|$.

6 pages, 2 figures, to appear in the proceedings of the XVII International Workshop on Deep Inelastic Scattering and Related Subjects DIS 2009, Madrid, Spain, April 26-30, 2009