Speaker
Description
Event shape observables have been widely used for precision QCD studies at various lepton and hadron colliders. We present recent calculations of the (transverse) energy-energy correlation event shape variable distributions in deep-inelastic scattering. In the framework of soft-collinear effective theory the cross section can be factorized as the convolution of the hard function, beam function, jet function and soft function in the back-to-back limit. A close connection to TMD factorization is established, as the beam function when combined with part of the soft function is identical to the conventional TMD parton distribution function, and the jet function is the second moment of the TMD fragmentation function matching coefficient. We validate our framework by comparing the obtained LO and NLO leading singular distributions to the full QCD calculations in the back-to-back limit. Results are obtained in the laboratory frame and the Breit frame (albeit with somewhat different observable definitions). In both cases we report the resummed (transverse) energy-energy correlation distributions up to N3LL accuracy matched with the NLO cross section. The Breit frame observable is shown to be insensitive to experimental pseudorapidity cuts, often imposed in the laboratory frame due to detector acceptance limitations. Non-perturbative effects are also discussed. The (T)EEC distributions provide a new way to precisely study TMD physics at the future Electron-Ion Collider.
