1CHEKANOV 2002B search for photoproduction of ${{\mathit X}}$ decaying into dijets in ${{\mathit e}}{{\mathit p}}$ collisions. See their Fig.$~$5 for the limit on the photoproduction cross section.
References:
CHEKANOV
2002B
PL B531 9
High Mass Dijet Cross Sections in Photoproduction at HERA