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Sep 27 – 30, 2016
DESY Hamburg
Europe/Berlin timezone

Conformal symmetry breaking and evolution equations in Quantum Chromodynamics

Sep 29, 2016, 2:00 PM
Seminar room 4a (DESY Hamburg)

Seminar room 4a

DESY Hamburg

Notkestrasse 85, 22607 Hamburg


Mr Matthias Strohmaier (University of Regensburg, Theoretical Particle Physics Department)


Quantum Chromodynamics (QCD) in non-integer d = 4 − 2e space-time dimensions possesses a nontrivial critical point where the theory enjoys exact scale and conformal invariance. As consequence there are three symmetry generators that commute with the renormalization group equation for composite operators. The resulting constraints allow to reconstruct full evolution kernels in physical (integer) dimensions from their eigenvalues (anomalous dimensions) and the calculation of the conformal anomaly at one order less in a perturbative expansion. We use this technique to derive three-loop, i.e. NNLO, evolution equations for flavor-nonsinglet quark-antiquark light-ray operators that encode the scale dependence of generalized hadron parton distributions and light-cone distribution amplitudes in the most compact form. In particular we calculate the two-loop correction to the generator of special conformal transformations at the critical point in the modified theory that corresponds to the two-loop conformal anomaly in the physical theory. Using this result we fix the off-diagonal part of the evolution kernel at NNLO.

Primary author

Mr Matthias Strohmaier (University of Regensburg, Theoretical Particle Physics Department)

Presentation materials