Contact
Name
Matthias Komm
Position
Former member
PhD student in CP3 from April 2013 to September 2017
Current position: Postdoc at Imperial College, London (UK).
Projects
I am involved in the following research directions:

Fast Simulation of the CMS experiment

A framework for Fast Simulation of particle interactions in the CMS detector (FastSim) has been developed and implemented in the overall simulation, reconstruction and analysis framework of CMS. It produces data samples in the same format as the one used by the Geant4-based (henceforth Full) Simulation and Reconstruction chain; the output of the Fast Simulation of CMS can therefore be used in the analysis in the same way as data and Full Simulation samples. FastSim is used in several physics analyses in CMS, in particular those requiring a generation of many samples to scan an extended parameter space of the physics model (e.g. SUSY) or for the purpose of estimating systematic uncertainties. It is also used by several groups to design future sub-detectors for the Phase-II CMS upgrades.
Related activities at UCL include the integration with the Full Simulation in the simulation of the electronic read-out ("digitization") and of the pileup of events from other proton-proton collisions, both in-time and out-of-time; the performance monitoring; and the overall maintenance and upgrade of the tracking-related code. Matthias Komm is current L3 convener of Tracking in FastSim, and Andrea Giammanco has been main responsible of the FastSim project from 2011 to 2013.

Single top studies at LHC

The electroweak production cross section of single top quarks is an important measurement for LHC, being a potential window on "new physics" effects.
Past achievements of this group include the very first measurement at 7 TeV (in t channel) with 2010 data, followed by the most precise inclusive cross section measurements of t-channel cross section at 7, 8 and 13 TeV, and the first differential measurements at 13 TeV; the most precise |Vtb| extraction from single top in the world; the first measurement of W-helicity fractions in a single-top topology; the first observation of the tW production mode; the first measurement of single-top polarization in t channel; stringent limits on anomalous tWb, tgu, tgc couplings.

External collaborators: CMS collaboration.

Testing the sign of the coupling of the new H(125) boson to top quarks with the CMS data

During 2012, the CMS and ATLAS collaborations independently reported unambiguous evidence of the existence of a new particle of mass around 125 GeV.
Several analyses are ongoing to challenge the hypothesis that the new particle is the SM Higgs. We focus on the search for its production in association with a single top quark. Due to an effect of quantum interference, this process is strongly suppressed in the Standard Model while it gets enhanced if its couplings to the top quark and to the W boson have opposite sign. An observation of this production mode would therefore be a convincing proof that this new particle does not belong to the Standard Model.
We published the first search for this process using 8 TeV data, and we expect to achieve sensitivity to anomalous values of the top Yukawa phase during the LHC Run-II.

External collaborators: CMS collaboration.


Show past projects.
Publications in CP3
Showing 5 publications over 11. Show all publications.
All my publications on Inspire

2017

The Phase-2 Upgrade of the CMS Tracker
CMS collaboration
[Full text] CERN-LHCC-2017-009 ; CMS-TDR-014
Refereed paper. 13th December.
Object definitions for top quark analyses at the particle level
CMS Collaboration
[Full text] CERN-CMS-NOTE-2017-004
Public experimental note. 6th June.

2016

Cross section measurement of $t$-channel single top quark production in pp collisions at $sqrt s =$ 13 TeV
Sirunyan, Albert M and others
[Abstract] [PDF] [Journal] Most precise measurement of the single-top cross section at 13 TeV.
Refereed paper. Public experimental note. 4th October.
Measurement of the differential cross section for t-channel single-top-quark production at sqrt(s)=13 TeV
CMS Collaboration
[Full text] CMS Physics Analysis Summary CMS-TOP-16-004
Public experimental note. 27th April.

2015

Measurement of top quark polarisation in t-channel single top quark production
Khachatryan, Vardan and others
[Abstract] [PDF] [Journal] JHEP 04 (2016) 073
Refereed paper. 9th November.


[UCLouvain] - [SST] [IRMP] - [SC]
Contact : Jérôme de Favereau
Research
Job opportunities Postdoctoral Position on advanced analysis techniques applied to the CMS di-Higgs study
Post-doctoral positions in collider phenomenology and particle astrophysics
Postodoctoral position in SoLid
EOS be.h : 10 PhD positions