18th MCnet Meeting and MCnetITN3 Mid-Term Review

22 Jan 2019, 13:00 → 25 Jan 2019, 12:30 Europe/Brussels

Salle Carnoy B059 (Institut des Sciences de la Vie (ISV))

Mike Seymour (University of Manchester)

18th MCnet Meeting and MCnetITN3 Mid-Term Review

The 18th meeting of the MCnet network is also the fourth meeting of the MCnetITN3 consortium, funded by the European Union’s Horizon 2020 research and innovation programme under the Marie- Skłodowska Curie grant agreement No. 722104

Organizers:

Chair : Michael Seymour

Admin : Ann Durie

Local : Céline Degrande, Fabio Maltoni

Local Admin : Carinne Mertens

 

logo-Marie-Curie-Actions.jpg

Tuesday, 22 January

MCnet Meeting: Management meeting

15:30 Coffee Break

MCnet Meeting: Management Meeting

19:00 Free dinner

Wednesday, 23 January

Network meeting: Overview and discussion on the MTR

Convener: Fabio Maltoni (UCL)

10:30 Coffee Break

Network meeting: Student and Post-doc session 🎓

Convener: Fabio Maltoni (UCL)

1 Hard diffraction in photoproduction

We present a new framework for modeling hard diffractive events in
photoproduction, implemented in Pythia 8.

Speaker: Christine Rasmussen

mcnet_jan2019_cor.pdf

2 String shoving in Heavy ions: Few ideas

We introduce a symmetric frame to study the interactions of a system of two strings for the string shoving mechanism within the Lund model. Considering all such pairs of string pieces in a collision, the resulting total momentum change on all such string pieces will be calculated.

Speaker: Ms Smita Chakraborty (Lund University)

TalkJan2019.pdf

3 Tuning of Merged Pythia

Monte Carlo Event Generators are important tools to understand the physics of particle colliders. Due to the complexity of particle collisions and the limited ability of perturbative QCD to describe the low energy behavior of partons, we need phenomenological models to provide a complete prediction of many observables. A systematic tuning of model parameters based on experimental data allows us to optimize the predictions of Monte Carlo Event Generators and refine our understanding the relevant models.

In this talk, I give an overview about tuning and discuss recent efforts of tuning Pythia in the context of matching and merging. Furthermore, I present AutoTunes, a framework for the simultaneous tuning of many parameters with automated weight setting.

Speaker: Leif Gellersen (Lund University)

leif_gellersen.pdf

4 Short-term internship at B12 consulting

A report of my experience at the consulting company B12 in the MCnet program for non-academic secondments.

Speaker: Mr Luca Mantani

B12%20presentation.pdf

12:30 Lunch

Network meeting: Student and Post-doc only session 🤓

15:30 Coffee Break

19:00 Aperodinner at the Louvain House

Thursday, 24 January

Mid-Term Review: Introduction

MCnetITN3_MTR_ESR talks_11 v3.pdf

5 Mid-Term Meeting, MCnetITN3

Presentation MTR MCNetITN3.ppt

Mid-Term Review: Tour de Table

Convener: Prof. Mike Seymour (University of Manchester)

MCnetITN3_MTR_ESR talks_11 v3.pdf

6 MCnetITN3 MTR Tour de Table

MCnetITN MTRvTour de table_slides v1.ppt

Mid-Term Review: Coordinator's Report

Convener: Prof. Mike Seymour (University of Manchester)

MCnetITN3_MTR_ESR talks_11 v3.pdf

7 Coordinator's Report - Scientific

MCnetITN3 MTR projects.pdf

8 Coordinator's Report - Training

MCnetITN3_MTR_training.pdf

9 Coordinator's Report: Management & Networking

MCnetITN3MidTerm.ppt

10:30 Coffee Break

Mid-Term Review: MCnetITN3 Fellows' Individual Reports

Convener: Prof. Mike Seymour (University of Manchester)

MCnetITN3_MTR_ESR talks_11 v3.pdf

13:00 Lunch

Mid-Term Review: Meeting between MCnetITN3 Fellows and EC REA Representatives

MCnetITN3_MTR_ESR talks_11 v3.pdf

Mid-Term Review: Restricted Session [EC REA representatives, MCnet academics, Partner Organisation reps., project manager only]

Convener: Prof. Mike Seymour (University of Manchester)

MCnetITN3_MTR_ESR talks_11 v3.pdf

16:00 Coffee Break

Mid-Term Review: Feedback and Open Discussion

Convener: Prof. Mike Seymour (University of Manchester)

MCnetITN3_MTR_ESR talks_11 v3.pdf

Dinner at Longeatude

Friday, 25 January

Network meeting: Student and Post-doc session 🎓

10 Four-jet DPS production in pp and pA collisions within the Pythia's framework

In spite of the recent progress in both theoretical and experimental studies many aspects of multiple parton interactions (MPI) still require a detail investigation. In particular, double parton scattering (DPS) processes can play a dominant role for some specific kinematic regions of multi-jet production, especially in proton-nucleus (pA) collisions where the total DPS cross section is approximately 3A times bigger as the corresponding total DPS cross section in proton-proton (pp) collisions.

In this talk I will present results I have got during the work on my MCNet short-term project, in particular I will consider two different ways to model double parton distribution functions, namely double DGLAP evolution equations and MPI formalism of the Pythia event generator, present a quantitative study of differences and similarities between both approaches and discuss their impact on various DPS sensitive differential distributions. Additionally I will compare predictions of a Pythia's built-in model of pA collisions (Angantyr) against theoretical computations currently available in the literature and show that it demonstrates a correct dependence of a total DPS cross section on a total number of nucleons.

Speaker: Oleh Fedkevych (Lund University )

Louvain_Fedkevych_pA_v1_0_2.pdf

11 A Parton-Level Simulation of Double Parton Scattering

Multiple parton interactions and, more specifically, double parton scattering are usually suppressed by single parton scattering. However, in some specific regions of phase-space, the differential cross sections are comparable. Also, for a given final state, it might happen that the double parton scattering is the dominant contribution if the single parton scattering is suppressed by a higher multiplicity of couplings. For these reasons, it turns out to be necessary to include double parton scattering in event generators in order to give a better description of the data at high energy scales such as at the LHC. The description of double parton scattering requires the use of double parton distributions and many efforts have been made during the last decade to produce realistic sets of those distributions, despite the lack of experimental data. In this presentation, we introduce a parton-level simulation of double parton scattering that combines a set of double parton distributions and an angular-ordered parton shower.

Speaker: Baptiste Cabouat (University of Manchester)

dPDFs.pdf

12 Recursive Matrix-Element Corrections in the Vincia Helicity Shower

The Vincia antenna shower is a plugin to Pythia which allows for multiple matrix-element corrections (MECs), as well as systematic shower uncertainty estimates. In this talk I will discuss the former, with a particular emphasis on how we used maximally-helicity-violating (MHV) amplitudes for the MECs. Finally, I will show a new ATLAS result for gluon splitting to b quarks which appears to prefer Vincia's ME-corrected shower to the standard event generators.

Speaker: Andrew Lifson (Lund University)

VinciaMCnetPresentation.pdf

13 Multiple emission kernels for parton showers

The future of parton showers is centered around increasing the accuracy and comparison to data especially as higher precision and higher orders become more important. In this talk I will present my work on the determination of emission kernels, focusing on the two emission case, and some of the necessary steps involved in the process.

Speaker: Emma Simpson Dore (KIT)

ESD_MCnetLouvain.pdf

10:30 Coffee Break

Network meeting: Student and Post-doc session 🎓

14 SingularPhasespace event generator

I present SingularPhasepace, a new hard process event generator soon to be implemented in Herwig. It will generate events that push steadily into a singular limit, whilst keeping as much fixed as possible. This will make it easier to test and validate Herwig's use of Matrix Elements and the Dipole Subtraction algorithm.

Speaker: Mr Kiran Ostrolenk

beamer.pdf

15 Top-quark effects in diphoton production through gluon fusion at NLO in QCD

We calculated the NLO QCD corrections to diphoton production through gluon fusion at the LHC, including both light quarks and the top quark. The two-loop amplitudes involving the top quark loop are evaluated through numerical methods proposed recently. We found that NLO QCD corrections are large, and the inclusion of top quark affects the results dramatically.

Speaker: Xiaoran Zhao (CP3)

diphoton.pdf

16 Bounding the Higgs width through interference effects

I review an ongoing pheno study, in which my collaborators and I explore if the experimental bounds on the Higgs decay width could potentially be improved by exploiting interference effects of the $pp \to H \to \gamma\gamma$ signal with the $pp \to \gamma\gamma$ continuum background. We use particle-level simulated data using SHERPA and a complete likelihood analysis to derive the expected bound, and thus go beyond earlier findings where approximate bounds were derived using fixed-order predictions [Dixon, Li 1305.3854 (2013)].

Speaker: Enrico Bothmann (ITP Göttingen)

Enrico_Bothmann-Higgs_Shift-MCnet_Meeting-Jan_2019.pdf

17 Studies of SM Monte Carlo and particle-level measurements in constraining new physics

As a joint task between MCnet and ATLAS, I will present the results of vector boson production in association with jets in the Herwig7 event generator, with multi-jet merging at next-to-leading order (NLO) accuracy. Next I introduce the idea of unfolding a detector level measurement and the ATLAS 4-lepton analysis. Finally, I will discuss how precision Monte Carlo predictions can be used alongside detector-corrected experimental data to set limits on new physics models in tools such as CONTUR.

Speaker: Danping Joanna Huang

MCnet-talk-jhuang.pdf