451 research outputs found
Chiral-odd pion generalized parton distributions beyond leading twist
We define in a systematic way, based on the light-cone collinear
factorization method, the chiral-odd generalized parton distributions (GPDs) of
a pseudoscalar hadron (such as the pi0) up to twist 5. For that, we introduce
the relevant matrix elements for 2-parton non-local operators, as well as
matrix elements for 3-parton non-local correlators. Their detailed
parametrization is fixed based on parity, charge conjugation and time reversal
invariance. This leads to the introduction of 20 real GPDs, whose symmetry
properties are explicitely given. The reduction of these GPDs to a minimal set
is performed by the use of constraints provided by QCD equations of motion and
rotation on the light-cone. We show that these 20 GPDs can be expressed through
8 GPDs which satisfy 4 integral sum rules. A surprising outcome of this
analysis is the fact that, when assuming the vanishing of 3-parton correlators,
as in the so-called Wandzura-Wilczek approximation, the whole set of GPDs
vanishes.Comment: 27 pages, 4 figures, 1 tabl
Hard Exclusive QCD Processes at the Linear Collider
The next generation of colliders will offer a possibility of clean
testing of QCD dynamics. Recent progress in the theoretical description of
exclusive processes permits for many of them a consistent use of the
perturbative QCD methods.
We find that already on the basis of Born approximation, the exclusive
diffractive production of two mesons from virtual photons at very high
energies should be measurable at the linear collider (LC).Comment: 6 pages, talk given at the International Conference on Linear
Colliders, Paris, 2004, 2 Postscript figures, uses sprocl.st
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