NLO evolution for large scale distances,positivity constraints and the low-energy model of the nucleon |
| |
| Institution: | 1. II. Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany;2. PRISMA Cluster of Excellence, Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany;3. Centre for Theoretical and Mathematical Physics and Department of Physics, University of Cape Town, Rondebosch 7700, South Africa;1. Institute of Nuclear and Particle Physics, National Center for Scientific Research Demokritos, Ag. Paraskevi, GR-15310 Athens, Greece;2. Department of Nuclear and Particle Physics, Faculty of Physics, University of Athens, Athens 15784, Greece;3. Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, Bern University, Sidlerstrasse 5, CH3012 Bern, Switzerland;1. Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040, Linz, Austria;2. Deutsches Elektronen–Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen, Germany;3. Institut für Theoretische Teilchenphysik, Campus Süd, Karlsruher Institut für Technologie (KIT), D-76128, Germany;1. Rudolf Peierls Centre for Theoretical Physics, 1 Keble Road, University of Oxford, OX1 3NP, Oxford, UK;2. Theoretical Physics Department, CERN, Geneva, Switzerland;1. Deutsches Elektronen–Synchrotron, DESY, Platanenallee 6, D–15738 Zeuthen, Germany;2. Johannes Kepler Universität Linz, Altenberger Straße 69, A-4040 Linz, Austria |
| |
| Abstract: | We present a computationally reliable and accurate method for solving the Gribov-Lipatov-Altarelli-Parisi equations at next to leading order, both in the non-singlet and in the singlet case. It requires solving numerically the renormalization group equations for the anomalous dimensions of composite operators in the complex plane, and finally performing an inverse Mellin transformation. In this way the group property of renormalization is exactly preserved, i.e. performing two successive scale transformations coincides exactly with a direct one making parton distributions independent of the integration path used to connect two different scales. This is relevant when large scale differences are involved and makes upward or downward evolution fully equivalent. Thus, it becomes possible to evolve the known parton distributions and leading twist contributions to the structure functions from Q2 = mb2 to the lowest possible scale imposed by positivity and unitarity. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
