Mrs
Simona Gargiulo
(Albert-Ludwigs-Universität Freiburg)
7/15/19, 2:00 PM
PQCD/MC
The modeling of top quark production (ttbar and single-top) and vector boson
production (W/Z) in association with heavy flavor jets constitutes one of the
largest uncertainties in the extraction of a Higgs to b-quarks signal at the LHC,
and is thus a crucial aspect to address on the way from the observation of this
decay to precise differential measurements. This talk will give an overview...
Mr
Marian Heil
(IPPP Durham)
7/15/19, 2:25 PM
PQCD/MC
Higgs boson production in association with two jets is an interesting process to measure the Higgs to weak-boson coupling (WBF).
However at the LHC the inclusive production of Hjj is dominated by the gluon
fusion component, where the Higgs boson couples to the gluon via a top loop.
The gluon fusion component is typically reduced by cuts requiring a large invariant dijet mass.
Such mass...
Dr
Andy Buckley
(University of Glasgow)
7/15/19, 3:15 PM
PQCD/MC
We propose a robust way of estimating and propagating uncertainties in the "tuning" of Monte Carlo event generator simulations to describe experimental data. This approach enhances the established eigentunes method by using a statistically sound coverage measure rather than an ad hoc tolerance scale to determine the size of parameter variations allowed by the data. The efficacy of the new...
Ms
Jeong Yeon Yook
(University of Zurich)
7/15/19, 3:40 PM
PQCD/MC
We consider the QCD cross section for vector boson pair production at the LHC, including off-shell effects, interferences and leptonic decays. The loop-induced gluon fusion production is quantitatively relevant in this process despite the fact that it enters at the second order in the QCD coupling. We present new results for the NLO corrections to the gluon fusion contribution for ZZ and WW...
Mr
Marius Höfer
(Universität Zürich)
7/15/19, 4:30 PM
PQCD/MC
Based on 1904.01044, I present recent results of a Next-to-Next-to-leading order (NNLO) calculation of inclusive isolated photon and photon-plus-jet production using the Monte-Carlo event generator NNLOJET. In order to mimic experimental photon isolation criteria we apply a staged isolation procedure. A smooth-cone isolation with small cone size is used to ensure numerical stability, followed...
Prof.
Marcello Fanti
(Universita` degli Studi di Milano)
7/15/19, 5:20 PM
PQCD/MC
The production of prompt isolated photons at hadron colliders provides stringent tests of
perturbative QCD and can be used to evaluate probability density functions of partons in the proton.
In this talk, we present the measurements of the isolated-photon plus two jets and the inclusive
isolated-photons cross sections, both measured using proton-proton collision data collected by
the ATLAS...
Miguel Arratia
(UC Berkeley)
7/15/19, 5:45 PM
PQCD/MC
I will present the results of the production of isolated photons and jets measured with the ALICE detector in proton-proton and proton-lead collisions at the LHC. These serve as reference points for perturbative QCD calculations, and for extracting nuclear modifications of fragmentation functions and PDFs. The ALICE detector complements other experiments at the LHC by covering a kinematic...
Dr
Stephen Jones
(CERN)
7/16/19, 4:30 PM
Higgs/EW/BSM
Currently, predictions for Higgs pair production at NLO in QCD including the exact top-quark mass dependence are known only numerically. The numerical calculations have proven to be adequate for making predictions up to moderate values of the Higgs pair invariant mass and Higgs boson transverse momentum. Unfortunately, the numerical calculations can be very compute-intensive to run and can...
Maddie McKay
(Southern Methodist University)
7/16/19, 4:55 PM
With the large pp collision dataset collected at 13 TeV, detailed measurements
of Higgs boson production can be performed in decays to bosons.
This talk presents measurements of differential cross sections in Higgs boson
decays to two photons or to four leptons, and a comparison to state-of-the-art
theory predictions.
Mr
Christopher Schwan
(Universita degli Studi di Milano)
7/16/19, 5:20 PM
Higgs/EW/BSM
Vector-boson scattering (VBS) denotes an interesting class of processes with small cross sections which recently have been measured or are about to be measured due to the increasing integrated luminosity at the LHC. They allow us to probe the electroweak symmetry breaking, in particular, the interplay between quartic-, triple-, and vector-vector-Higgs couplings. In this talk I will briefly...
Johannes Michel
(DESY Hamburg)
7/16/19, 5:45 PM
Higgs/EW/BSM
In this talk I present a new endpoint factorization theorem
that generalizes the classic soft threshold factorization for Drell-Yan-like processes.
It fully captures both soft and collinear dynamics,
including nondiagonal partonic channels that are neglected in the standard soft limit.
This allows us to construct a fixed-order approximant for the cross section
that covers all singular...
Mr
Paolo Gunnellini
(Hamburg University)
7/16/19, 6:10 PM
Simon Badger
(IPPP Durham)
7/18/19, 2:00 PM
I will describe some recent results for two-loop amplitudes with five external legs reconstructed
using numerical evaluations over finite fields. This technique avoid many of the bottlenecks of traditional
methods and is well suited to amplitudes with many kinematic scales.
Mr
Johannes Schlenk
(IPPP)
7/18/19, 2:25 PM
PQCD/MC
PySecDec is a program for the numerical calculation of dimensionally regulated parameter integrals, in particular multi-loop integrals.
In this talk new developments in the program such as Quasi-Monte Carlo methods and GPU support will be presented.
Applications to multi-loop amplitude calculations will be discussed.
Mr
Ulrich Schubert
(Universtiy at Buffalo)
7/18/19, 2:50 PM
The large production rate of top quarks at LHC enables precision studies of top quark observables, which potentially could uncover evidence for new physics. In order to achieve this the precision studies have to be met with equally precise theory predictions. One of the key processes is top quark pair production through the annihilation of a quark pair. While numerical representations already...
Mr
Giuseppe De Laurentis
(IPPP, Durham University)
7/18/19, 3:15 PM
PQCD/MC
I will present a new method (arXiv:1904.04067) to generate analytic expressions for the integral coefficients of loop amplitudes using numerical evaluations only. We use high precision arithmetic to explore the singularity structure of the coefficients and decompose them into parts of manageable complexity. Each part is isolated by choosing an appropriate region of phase space, and...
Andrzej Siodmok
(IFJ PAN)
7/18/19, 3:40 PM
PQCD/MC
We consider soft gluon evolution at the amplitude level to expose the
structure of colour reconnection from a perturbative point of view.
Considering the cluster hadronization model and an universal Ansatz for
the soft anomalous dimension we find strong support for geometric models
considered earlier. We also show how reconnection into baryonic systems
arises, and how larger cluster...