Conveners
QCD & EW II
- Bin Yan (Michigan State University)
We point out the deficiency of the phenomenological definition of the valence partons as the difference between the partons and antipartons in the NNLO evolution equations and show that the classification of the partons of the valence and connected sea from the path-intergral formulations QCD in terms of the hadronic tensor and the quasi-PDF with LaMET resolves this issue.
The parton distribution functions (PDFs) are process-indenpendent information of the quark and gluon inside the hadron. Even though gluon PDF could be obtained from the global fit of the experimental data and dominates at the small x region, gluon PDF studies from theoretical side are much fewer then quark PDF. We present the results to access the x-dependence of the gluon unpolarized PDF...
Strange PDF is important for us to understand the nucleon structure and the test of electroweak interactions, but is not significantly constrained by experimental data. We present the first preliminary results of the unpolarized strange PDF from lattice calculation in the large momentum effective theory (LaMET) approach. The calculation is done on a lattice with lattice spacing $a\approx0.12$...
The collinear factorization of the photon parton distribution function (PDF), such as the Weizsaicker-Williams approximation, i.e., ``equivalent photon approximation (EPA)'', works very well at the low and intermediate energies. However, with energy increasing above the electroweak (EW) scale $(v)$, the photon mixes with $Z$-boson, which makes the photon PDF not well defined, anymore....
The Weizsaicker-Williams approximation, i.e., ''equivalent photon approximation'', is a powerful tool, both in understanding the electromagnetic radiation and in studying the photon interaction processes. Just like the quark and gluon partons in quantum chromodynamics, photon could be treated as a parton constituent in the initial state beam particles and described using a photon parton...
The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous weak boson self interactions. In this talk, we present recent results on weak-boson fusion and weak-boson scattering from the ATLAS experiment using proton-proton collisions at √s=13 TeV. We present the first observation of ZZ production via weak-boson scattering as well as...
