High energy scattering in Quantum Chromodynamics
We study the behaviour of scattering amplitudes in the Regge asymptotics, where the c.m. energy is large compared to all masses and momentum transfers. If there is a second momentum scale, large compared to the hadronic scale but much smaller than the energy, then essential features of the scattering process can be calculated perturbatively. Semi-hard processes are an interesting field of phenomenology.
The high-energy effective action has been shown to be a uselful tool for analyzing the Regge asymptotics in gauge theories. This action describes the scattering of partons by the exchange of reggeized quaks and gluons. The parton interaction in the Bjorken asymptotics can be considered in an analogous effective action framework. The asymptotic interaction in both Regge and Bjorken limits exhibit remarkable symmetry properties and are related to integrable quantum spin chains.
Some reviews
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L.N. Lipatov, Small-x physics in pert. QCD, Phys. Reports 286 (1997) 131, ps file hep-ph/9610276
R. Kirschner, Small-x physics, Zakopane school 1995, Acta Physica Polonica B26 (1995),1961,
J.R. Forshaw and D.A. Ross, Quantum Chromodynamics and the Pomeron, Cambridge Univ. Press 1997.
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Some recent results
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The Bjorken asymptotics has been investigated in super Yang-Mills theory.
authors: R. Kirschner,
Solutions of the Yang-Baxter equation with Jordanian deformation of onformal symmetry have been found.
authors: S. Derkachov, D. Karakhanyan, R. Kirschner
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For references and papers please consult SPIRES at SLAC or at DESY.
Collaboration and related research groups
L.N. Lipatov (St. Petersburg), L. Szymanowski (Warsaw), D.Yu. Ivanov (Novosibirsk). S.E. Derkachov (St. Petersburg), D. Karakhanyan (Yerevan),
J. Bartels (Hamburg Univ., DESY), J. Blumlein (DESY-Zeuthen), V.M. Braun (Regensburg), M. Ciafaloni (Firenze), V. Fadin (Novosibirsk), G. Korchemsky (Paris-Orsay), G. Marchesini (Milano), A.H. Mueller (Columbia Univ.), A. Schäfer (Regensburg).
Financial support (beyond University budget)
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Deutsche Forschungsgemeinschaft, post-doc position 1997, 1999-2000.
German Bundesministerium f. Forschung und Technologie, BMBF, Projektträger HEP, post doc position 1997-98.
BMBF, Polish-German agreement on scientific and technological collaboration, travel support Warsaw-Leipzig, 1996-1999.
Volkswagen-Stiftung, travel support St. Petersburg - Leipzig, Warsaw - Leipzig, 1996-1998.
Saxonian Ministry of Science and Arts, travel supports for guests.
European Commission, Marie Curie Fellowship (Host Institute), 2000.
BMBF/IB, Scientific collaboration with Armenia, 2001-2003.
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