Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

© The Author(s) 2011. First measurements are presented of the diffrac-tive cross section σ<inf>ep→e</inf>XY at centre-of-mass energies √s of 225 and 252 GeV, together with a precise new measurement at √s of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at √s of 301 GeV, the measurements are used to extract the diffractive longitudinal structure function FD in the range of photon virtualities 4.0 < Q<sup>2</sup> < 44.0 GeV<sup>2</sup> and fractional proton longitudinal momentum loss 5 x 10-<sup>4</sup>≤xp ≤ 3×10<sup>−3</sup>. The measured F<sup>D</sup> <inf>L</inf> is compared with leading twist predictions based on diffractive parton densities extracted in NLO QCD fits to previous measurements of diffractive Deep-Inelastic Scattering and with a model which additionally includes a higher twist contribution derived from a colour dipole approach. The ratio of the diffractive cross section induced by longitudinally polarised photons to that for transversely polarised photons is extracted and compared with the analogous quantity for inclusive Deep-Inelastic Scattering.

Original publication

DOI

10.1140/epjc/s10052-011-1836-6

Type

Journal article

Journal

European Physical Journal C

Publication Date

01/01/2011

Volume

71