68 research outputs found
Anomalous GPDs in the photon
We consider deeply virtual Compton scattering (DVCS) on a photon target, in
the generalized Bjorken limit, at the Born order and in the leading logarithmic
approximation. This leads us to the extraction of the photon anomalous
generalized parton distributions (GPDs) \cite{url, DVCSphoton}.Comment: To appear in the proceedings of Photon 2007: International Conference
on the Structure and Interactions of the Photon and the 17th International
Workshop on Photon-Photon Collisions and International Workshop on High
Energy Photon Linear Colliders, Paris, France, 9-13 Jul 200
Probing photon structure in DVCS on a photon target
The factorization of the amplitude for the deeply virtual Compton scattering
(DVCS) process gamma*(Q) gamma -> gamma gamma at high Q2 is demonstrated in two
distinct kinematical domains, allowing to define the photon generalized parton
distributions and the diphoton generalized distribution amplitudes. Both these
quantities exhibit an anomalous scaling behaviour and obey new inhomogeneous
QCD evolution equations.Comment: 3 pages, 1 figure, to be published in the proceedings of the PANIC
2008 conference, Eilat (Israel), November 200
Deeply Virtual Compton Scattering on a Photon and Generalized Parton Distributions in the Photon
We consider deeply virtual Compton scattering on a photon target, in the generalized Bjorken limit, at the Born order and in the leading logarithmic approximation. We interpret the result as a factorized amplitude of a hard process described by handbag diagrams and anomalous generalized parton distributions in the photon. This anomalous part, with its characteristic ln Q2 dependence, is present both in the DGLAP and in the ERBL regions. As a consequence, these generalized parton distributions of the photon obey DGLAP-ERBL evolution equations with an inhomogeneous term
Hard exclusive processes with photons
Virtual photons have proven to be very efficient probes of the hadronic
structure, mostly through deep inelastic scattering and related processes. The
advent of high luminosity lepton beams has allowed to enlarge the studied
processes to hard exclusive reactions, such as deeply virtual Compton
scattering and the electroproduction of mesons. We discuss theoretical progress
which has lately been quite remarkable in this domain and first much
encouraging experimental data.Comment: 3 pages, to be published in the proceedings of the International
Conference on the Structure and Interactions of the Photon (Photon 2007)
Paris, july 200
Growth modes of Fe(110) revisited: a contribution of self-assembly to magnetic materials
We have revisited the epitaxial growth modes of Fe on W(110) and Mo(110), and
propose an overview or our contribution to the field. We show that the
Stranski-Krastanov growth mode, recognized for a long time in these systems, is
in fact characterized by a bimodal distribution of islands for growth
temperature in the range 250-700°C. We observe firstly compact islands
whose shape is determined by Wulff-Kaischev's theorem, secondly thin and flat
islands that display a preferred height, ie independant from nominal thickness
and deposition procedure (1.4nm for Mo, and 5.5nm for W on the average). We
used this effect to fabricate self-organized arrays of nanometers-thick stripes
by step decoration. Self-assembled nano-ties are also obtained for nucleation
of the flat islands on Mo at fairly high temperature, ie 800°C. Finally,
using interfacial layers and solid solutions we separate two effects on the
preferred height, first that of the interfacial energy, second that of the
continuously-varying lattice parameter of the growth surface.Comment: 49 pages. Invited topical review for J. Phys.: Condens. Matte
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