Mainz 2014 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 93: QCD 1
T 93.8: Vortrag
Mittwoch, 26. März 2014, 18:30–18:45, GFH 01-721
αs running from QCD fits to collider data — •Oleg Kuprash1,2 and Achim Geiser1,2 — 1Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany — 2Hamburg University, Institute of Experimental Physics, Hamburg, Germany
There are plenty of measurements of the strong coupling constant αs(µ) performed at different energy scales µ by different collider experiments (LHC, Tevatron, HERA, LEP, ...). However, in most of these, the standard QCD running of αs is implicitly assumed during extraction of the αs(µ) values from the data. In this work we are aiming to check the running of αs by varying one of its parameters, the number of active massive flavours participating in virtual loops that contribute to the αs evolution, in a simultaneous QCD fit of the proton parton density functions (PDF) and αs. The fit is performed to the world pp, pp and ep collider data, using predictions of perturbative QCD at one-loop order. While the number of virtual flavours in the αs running is artificially varied during the fit, the number of real flavours is fixed to standard QCD values in order to leave the initial and final state configurations unchanged. The study can be considered as a test of perturbative QCD, but is also expected to be sensitive to virtual effects of possible new particles at very high energies.