Measurement of the diffractive longitudinal structure function F-L(D) at HERA
H1 Collaboration (ukupan broj autora: 205)
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First measurements are presented of the diffractive cross section sigma(ep) - GT eXY at centre-of-mass energies root s of 225 and 252 GeV, together with a precise new measurement at root s of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at root s of 301 GeV, the measurements are used to extract the diffractive longitudinal structure function F-L(D) in the range of photon virtualities 4.0 LT = Q(2) LT = 44.0 GeV2 and fractional proton longitudinal momentum loss 5 x 10(-4) LT = x(P) LT = 3 x 10(-3). The measured F-L(D) 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 i...s extracted and compared with the analogous quantity for inclusive Deep-Inelastic Scattering.
Source:European Physical Journal C. Particles and Fields, 2011, 71, 12
- Helmholtz Association (HGF) [VH-NG-401], Bundesministerium fur Bildung und Forschung, FRG [05H09GUF, 05H09VHC, 05H09VHF, 05H16PEA], UK Science and Technology Facilities Council, UK Particle Physics and Astronomy Research Council, FNRS-FWO-Vlaanderen, IISN-IIKW, IWT, Interuniversity Attraction Poles Programme, Belgian Science Policy, Polish Ministry of Science and Higher Education [DPN/N168/DESY/2009], Deutsche Forschungsgemeinschaft, VEGA SR [2/7062/27], Swedish Natural Science Research Council, Ministry of Education of the Czech Republic [LC527, INGO-LA09042, MSM0021620859], Swiss National Science Foundation, CONACYT, Mexico [48778-F], Russian Foundation for Basic Research (RFBR) [1329.2008.2], European Social Fund, National Resources (EPEAEK II)-PYTHAGORAS II, Romanian National Authority for Scientific Research [PN 09370101], Ministry of Science of Montenegro [051/3-3352]