학술논문

Unbinned Deep Learning Jet Substructure Measurement in High $Q^2$ ep collisions at HERA
Document Type
article
Source
Subject
hep-ex
Language
Abstract
The radiation pattern within high energy quark- and gluon-initiated jets (jetsubstructure) is used extensively as a precision probe of the strong force aswell as an environment for optimizing event generators with numerousapplications in high energy particle and nuclear physics. Looking atelectron-proton collisions is of particular interest as many of thecomplications present at hadron colliders are absent. A detailed study ofmodern jet substructure observables, jet angularities, in electron-protoncollisions is presented using data recorded using the H1 detector at HERA. Themeasurement is unbinned and multi-dimensional, using machine learning tocorrect for detector effects. All of the available reconstructed objectinformation of the respective jets is interpreted by a graph neural network,achieving superior precision on a selected set of jet angularities. Trainingthese networks was enabled by the use of a large number of GPUs in thePerlmutter supercomputer at Berkeley Lab. The particle jets are reconstructedin the laboratory frame, using the $k_{\mathrm{T}}$ jet clustering algorithm.Results are reported at high transverse momentum transfer $Q^2>150$ GeV${}^2$,and inelasticity $0.2 < y < 0.7$. The analysis is also performed in sub-regionsof $Q^2$, thus probing scale dependencies of the substructure variables. Thedata are compared with a variety of predictions and point towards possibleimprovements of such models.