Factorisation breaking in diffractive dijet photoproduction at HERA?
  Recent experimental data on dijet cross sections in diffractive photoproduction at HERA collider are analysed with an emphasis on QCD factorisation breaking effects. The possible sources of the contradiction in conclusions of H1 and ZEUS collaborations such as different hadronisation corrections and different phase space of both analyses are studied. 
Radek \v{Z}leb\v{c}\'ik, Karel \v{C}ern\'y, Alice Valk\'arov\'a
hep-ph hep-ex