**29**: 497-513

https://doi.org/10.1140/epjc/s2003-01262-9

experimental physics

## Measurement of inclusive jet cross sections in photoproduction at HERA

Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of $e^+ p \rightarrow e^+ + jet + X$ events in the kinematic range of photon virtualities $Q^2 \leq 1 \mathrm{GeV}^2$ and photon-proton centre-of-mass energies $95 \leq W_{\gamma p} \leq 285 \mathrm{GeV}$ represents an integrated luminosity of $24.1 \mathrm{pb}^{-1}$. Jets are defined using the inclusive $k_{\bot}$ algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy *E*
_{
T
}
^{
jet
} and pseudorapidity $\eta^{ jet}$ in the domain $5 \leq E_T^{ jet} \leq 75 \mathrm{GeV}$ and $-1 \leq \eta^{ jet} \leq 2.5$. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in *E*
_{
T
}
^{
jet
}, which varies by six orders of magnitude over the measured range, is compared with similar distributions from $p \overline{p}$ colliders at equal and higher energies.

*© Springer-Verlag, 2003*