HERA Symposium: recent highlights from experiment and theory

Aharon Levy (Tel Aviv University)
Robert Thorne (UCL)
Alice Valkarova (Charles Univ., Prague)
Charlotte Van Hulse (Univ. of the Basque Country)
Auditorium, 16.30 - 18.30 h

Highlights from the HERA experiments and their impact in theory are presented. Recently, all measurements of inclusive deep inelastic scattering from H1 and ZEUS have been combined and QCD fits to the parton densities in the proton performed. The 15 years of data taking culminated in 3000 points which have been combined and their impact will be lasting for years to come at the LHC and other facilities. The final measurements of the longitudinal proton structure function have also recently been completed. Considering specific quarks in the proton, H1 and ZEUS have new measurements on the charm and beauty contribution to the proton and HERMES have a new determination of the strange quark density. In addition, semi-inclusive deep-inelastic scattering data collected at HERMES on a transversely polarized hydrogen target have recently allowed a multi-dimensional extraction of asymmetries that provide access to various transverse-momentum-dependent parton distribution functions, sensitive to correlations between quark spin, proton spin, the transverse momentum of quarks and/or of final-state hadrons. Turning to a three-dimensional image of the nucleon in longitudinal-momentum and transverse-position space, a recent extraction of SDMEs in exclusive omega production provides data helpful in constraining model calculations. Recent jet measurements at HERA have enabled the strong coupling constant to be measured with an experimental precision of <1%. This has been achieved through the simultaneous measurement of inclusive-jet, dijet and trijet cross sections. The use of HERA data in determination of the parton densities in the proton have the highest impact in theory and phenomenology and a theoretical perspective is her given. The importance of HERA data from the hadronic final state on theory is also outlined as well as future improved calculations. The Symposium acts as an introduction to a 2-day HERA Workshop, that will highlight crucial analyses and areas of physics which have still yet to be investigated and consider their impact on theory and other facilities and experiments.

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