Prof. Iain Bertram (Lancaster University)
7/15/19, 2:00 PM
Theoretical calculations for jet substructure observables with accuracy beyond leading-logarithm have recently become available. Such observables are significant not only for probing a new regime of QCD at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many searches for physics beyond the Standard Model. In this talk, we discuss a...
Darren Scott (University of Amsterdam/Nikhef)
7/15/19, 2:25 PM
For many high-energy processes at the LHC involving hadronic final states, one often encounters jet functions in the factorisation theorems which can be used to resum various logarithmically enhanced contributons. The resummation of jet radius logarithms has been studied before for inclusive jet production and exclusive jet production. We investigate what happens in the transition between...
7/15/19, 2:50 PM
We will present new calculations of the jet gap jet cross sections at the LHC using the BFKL NLL formalism and comparisons between Tevatron D0 and CDF data. Predictions for jet gap jet cross sections at the LHC will also be given. For the first time, predictions will include NLO impact factors, which is absolutely needed in order to compare with data. New numerical methods were used in order...
Davide Napoletano (IPht, CEA Saclay)
7/15/19, 3:15 PM
In this talk I will show how the resummation for the jet mass, in the presence of a cut on some jet-shape, can be extended to the region where this cut takes some finite value, which often represents a more realistic situation. In particular, and to highlight the main points, I will focus on $N$-Subjettinss with $\beta=2$, although the method is, in principle, completely general.
Vincent Theeuwes (University of Goettingen)
7/15/19, 3:40 PM
Over the years many different types of fits for the strong coupling constant have been performed. However one type of high precision result that currently significantly differs from the world average are results from event shapes at electron positron colliders. One possible source for the difference in these results could be the degeneracy between the fit of the strong coupling constant...
Dr Stefano Carrazza (University of Milan)
7/16/19, 2:00 PM
We introduce a novel implementation of a reinforcement learning algorithm which is adapted to the problem of jet grooming, a crucial component of jet physics at hadron colliders. We show that the grooming policies trained using a Deep Q-Network model outperform state-of-the-art tools used at the LHC such as Recursive Soft Drop, allowing for improved resolution of the mass of boosted...
Dr Lin Dai (Duke University)
7/16/19, 2:25 PM
We study quarkonium production within jets based on the fragmenting jet function (FJF) formalism which describes the distribution of a quarknium in a jet with certain jet shape. FJF incorporates quarkonium fragmentation functions which can be obtained using NRQCD factorization formalism. Thus, the study of quarkonium production in jets also provides a test of NRQCD. In this talk, I will...
Dr Andy Buckley (University of Glasgow)
7/16/19, 2:50 PM
Gluon splitting to b-quark pairs is a unique probe of the properties of gluon fragmentation, as the identified b-tagged jets provide a proxy for the quark daughters of the initial gluon. We present a measurement of key differential distributions related to g→b bbar using data collected with the ATLAS detector at √s=13 TeV. Track jets are used to probe angular scales below the standard R=0.4...
7/16/19, 3:15 PM
I will discuss the current status of the ResBos 2 project. The focus will be on accuracy of the resummation calculation, and the comparison to LHC data for $p_T$, $\phi^*_\eta$, and the angular coefficients for Drell-Yan. In addition, details pertaining to the ongoing studies of the detailed theoretical uncertainties that arise from the resummation calculation in the measurement of the $W$...
Ms Ashley Parker (SUNY Buffalo)
7/16/19, 3:40 PM
Dr Simone Marzani (Università di Genova & INFN Genova)
7/18/19, 2:00 PM
We discuss the jet shape variable pull and in particular, we present a first-principle prediction for the pull angle, which can help to probe the colour flow between jets. While the pull angle is not infra-red and collinear safe, it is Sudakov safe and therefore it can be calculated using all-order techniques, which share similarities to standard transverse-momentum resummation. We compare...
Daniel Reichelt (Göttingen University)
7/18/19, 2:25 PM
We present predictions for Durham jet resolution scales $y_n$ in multijet production in $e^+e^−$ collisions at NLL accuracy matched to LO. We use the well known CAESAR formalism as a basis and extract the required color information for matrix elements with a large number of jets using tools from the matrix element generator Comix within the Sherpa framework. We discuss the effect of subleading...
Mr Marcel Balsiger (Institute for Theoretical Physics, University of Bern, Switzerland)
7/18/19, 2:50 PM
Over the last few years, there has been a lot of progress concerning non-global jet observables. Recently, we managed to resum the interjet energy flow and the jet mass at the NLL'-level, meaning that our results include the full next-to-leading-order corrections to the hard, jet and soft functions which are implemented in a parton-shower framework that generates the renormalization-group...
Duff Neill (LANL)
7/18/19, 3:15 PM
Scattering processes often inevitably include the production of infra-red states, which are highly correlated with the hard scattering event, and decohere the hard states. The hard reduced density matrix (tracing out infra-red states) has a non-zero entropy. We describe this entropy for an asymptotically-free gauge theory by separating the Hilbert space into hard and infra-red states, and...