| Abstract | A first measurement of the longitudinal diffractive structure function
$F_L^D$ using the H1 detector at HERA is presented. The structure
function is extracted from first measurements of the diffractive
cross section at centre of mass energies $\sqrt{s}$ of 225 and 252 GeV,
together with a new measurement at $\sqrt{s}$ of 319 GeV, using data
taken in 2007 at high values of inelasticity $y$. The measured $F_L^D$
is compared to predictions from NLO QCD fits to previous measurements of
the inclusive diffractive DIS cross section. |
