Conveners
Monte Carlo and resummation
- There are no conveners in this block
Monte Carlo and resummation: Joint with PDFs, 𝛼ₛ and soft QCD
- Simon Platzer (University of Vienna (AT))
- Stefano Camarda (Johannes Gutenberg Universitaet Mainz (DE))
- Steffen Schumann (Georg-August-Universitaet Goettingen)
- Josh McFayden (CERN)
- S. Moch (UHH)
Monte Carlo and resummation
- There are no conveners in this block
Monte Carlo and resummation
- There are no conveners in this block
Monte Carlo and resummation
- There are no conveners in this block
Monte Carlo and resummation
- There are no conveners in this block
We discuss the automation of the calculation of leading- and next-to-leading order contributions to short-distance cross sections at hadron colliders. With the new public version of the code MadGraph5_aMC@NLO, not only NLO QCD and EW corrections but also all the subleading contributions in a mixed QCD and EW coupling expansion can now be calculated. We discuss the key features for obtaining...
In this status report on the multi-purpose Monte-Carlo event generator Sherpa
I review recent and ongoing Sherpa studies, as well as the latest
developments of its fixed-order and all-order technologies. Fixed-order
improvements I discuss include fully automated EW corrections and support
for additional loop-induced processes. On the all-order side I cover
Sherpa's parton showers and the...
A number of Higgs measurements and searches for new phenomena in the Higgs sector rely on identification or vetos of particle jets with fairly low transverse momentum in the range of 20-30 GeV. In these cases uncertainties from the modelling of the parton shower and the underlying event can be sizeable. This talk will give an overview of how these uncertainties enter in several analyses.
Abstract will be available shortly. The talk has been suggested by the organizer
ATLAS + CMS.
The content of this talk is related to the activities of one the CMS groups (Generator, Forward, SM, Top) and ATLAS groups (PMG, SM, TOP, Forward).
We present a direct space resummation formalism for colour singlet production in hadronic collisions. We focus on N3LL results for Higgs boson production in gluon-gluon fusion as well as results for Drell-Yan production, we show predictions with phenomenological cuts matched to NNLO fixed-order predictions.
The weak boson fusion contribution to Higgs boson production is enhanced significantly by requiring a large invariant mass and rapidity separation between the associated jets. This induces large logarithmic corrections in the prediction for the gluon-fusion background, which are incorporated to all orders within the High Energy Jets (HEJ) formalism. We present HEJ predictions for the...
We consider soft gluon evolution of a system of clusters forming the initial state of the cluster hadronziation model, in order to constrain colour reconnection models from a perturbative point of view.
We show that this ansatz produces clusters with properties attributed to
a colour pre-confined state and find strong evidence for formerly investigated colour reconnection models based on...
NLO-subtraction schemes such as CS-dipole-subtraction are indispensable for MC-Generators to calculate real and virtual corrections efficiently. However, those algorithms suffer from numerical inefficiencies and even cause distortions in physical distributions when interfaced with parton showers, if the process in question comprises potentially resonant particles.
In this talk I will elucidate...
I will discuss recent developments in the calculation of next-to-leading power corrections in Drell Yan and other electroweak annihilation processes.
We present a new algorithm to incorporate calculations with massive $b$-quarks, usually performed in the four flavour scheme, into a merged simulation obtained in the five flavour scheme. We apply this algorithm to $tt+\mathrm{jets}$ / $ttbb$ production, study the uncertainties of this newly developed method and compare our results to dedicated 4F/5F simulations.
We study the transverse momentum spectrum for Drell-Yan production including the bottom mass effect. The pt-distribution of DY or Z boson is very important observable at the LHC, particularly to the ratio of W boson and Z boson spectrum to precisely measure of the W boson mass. The presence of an extra mass scale namely the bottom mass along with the hard scale and the pt-scale makes it very...
Perturbative calculations for many collider observables suffer from large logarithmic corrections associated with soft emissions or radiation collinear to beam or jet directions. Resummation using SCET techniques is based on factorisation theorems, and requires the calculation of jet, soft and beam functions to some perturbative accuracy. This task has up to now mainly been achieved...
Starting from a factorization theorem in effective field theory, we derive a parton-shower equation for the resummation of non-global logarithms. We have implemented this shower and interfaced it with a tree-level event generator to obtain an automated framework to resum the leading logarithm of non-global observables in the large-Nc limit. Using this setup, we compute gap fractions for dijet...
The total pp cross section is a fundamental observable at the LHC. It can be derived from the measurement of the elastic cross section, using the optical theorem. Measurements of the elastic proton-proton cross section were performed at a center-of-mass energy of 8 TeV at various settings of the beam optics using the ALFA detector.
The ALFA detector is also used to tag forward protons in...
Latest results from Underlying event measurements from ATLAS and CMS are presented.
