What HERA may provide ?
Hannes Jung, Albert De Roeck, Jochen Bartels, Olaf Behnke, Johannes Blumlein, Stanley Brodsky, Amanda Cooper-Sarkar, Michal Deak, Robin Devenish, Markus Diehl, Thomas Gehrmann, Guenter Grindhammer, Gosta Gustafson, Valery Khoze, Albert Knutsson, Max Klein, Frank Krauss, Krzysztof Kutak, Eric Laenen, Leif Lonnblad, Leszek Motyka, Paul R. Newman, Fred Olness, Daniel Pitzl, Marta Ruspa, Agustin Sabio Vera, Gavin P. Salam, Thomas Schorner-Sadenius, Mark Strikman
TL;DR
This paper maps a comprehensive program for extracting fundamental QCD insights from HERA data, emphasizing the measurement of parton distribution functions, the universality of the hadronic final state, and potential deviations from linear QCD evolution. It discusses both the experimental measurements—spanning inclusive, semi-inclusive, and diffractive processes—and the theoretical developments needed (e.g., higher-order calculations, unintegrated PDFs, saturation) to interpret results. A strong emphasis is placed on the tuning and validation of Monte Carlo event generators using interconnected data-interpretation tools (HZTOOL/RIVET) and on preserving the HERA data infrastructure for long-term use at the LHC and future colliders. The document also items a detailed wish-list of measurements and proposals (intrinsic heavy quarks, exclusive/diffractive processes, and Odderon searches) to push the frontiers of QCD understanding in a controlled ep environment.
Abstract
More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given.