Measurement of the Diffractive Longitudinal Structure Function F_L^D at HERA

Abstract

First measurements are presented of the diffractive cross section ${\sigma }_{ep\to eXY}$ at centre-of-mass energies $\sqrt{s}$ of 225 and 252 GeV, together with a precise new measurement at $\sqrt{s}$ of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at $\sqrt{s}$ 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 <= Q^2 <= 44.0 GeV^2 and fractional proton longitudinal momentum loss 5 10^{-4} <= x_{IP} <= 3 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 is extracted and compared with the analogous quantity for inclusive Deep-Inelastic Scattering.

35 pages, 10 figures and 6 tables

References in corpus (5)

• Measurement of the Inclusive e{\pm}p Scattering Cross Section at High Inelasticity y and of the Structure Function FL
• Measurement of the Diffractive Deep-Inelastic Scattering Cross Section with a Leading Proton at HERA
• A Vertex Trigger based on Cylindrical Multiwire Proportional Chambers
• Target mass and finite $t$ corrections to diffractive deeply inelastic scattering
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Cited by in corpus (12)

• The Large Hadron-Electron Collider at the HL-LHC
• Deep inelastic cross-section measurements at large y with the ZEUS detector at HERA
• Inclusive Measurement of Diffractive Deep-Inelastic Scattering at HERA
• First global next-to-leading order determination of diffractive parton distribution functions and their uncertainties within the {\tt xFitter} framework
• Phenomenology of diffractive DIS in the framework of fracture functions and determination of diffractive parton distribution functions
• Role of higher twist effects in diffractive DIS and determination of diffractive parton distribution functions
• Determination of diffractive PDFs from global QCD analysis of inclusive diffractive DIS and dijet cross-section measurements at HERA
• Twist-3 Contributions in Semi-Inclusive DIS in the Target Fragmentation Region
• Diffractive longitudinal structure function at the Electron Ion Collider
• QCD fits in diffractive DIS revisited
• Diffractive Structure Functions with H1
• A global QCD analysis of diffractive parton distribution function considering higher twist corrections within the xFitter framework