Andrea Giammanco
Centre for Cosmology, Particle Physics and Phenomenology - CP3
Université catholique de Louvain
2, Chemin du Cyclotron - Box L7.01.05
B-1348 Louvain-la-Neuve
+32 10 47 3221
My personal homepage
UCL member card
People responsibilities
Hamed Bakhshiansohi (MOVE-IN), member since January 2016
My main interest is to search for the signatures of new physics in the CMS data. My current research is based on a search for the Dark Matter candidate which is produced in associated with top quark pair in proton-proton collisions at LHC. This search could benefit the Matrix Element method to separate the ttbar background from signal.

Pieter David, member since February 2016
Experimental particle physicist, member of the CMS collaboration. Currently working on measurements of processes involving top quarks in order to constrain higher-order EFT operators.

Abideh Jafari (FNRS), member since April 2014
I am analyzing CMS data to precisely measure the single top quark properties and to search for new physics in this sector. I am also interested in possible Higgs boson decays to new particles in the framework of Two Higgs Doublet models.

PhD students
Matthias Komm (FRIA), member since April 2013
Top Quark Physics: precision measurements and searches for beyond SM physics with CMS. Also involved in Fast Simulation development of the CMS detector.

Georgios Konstantinos Krintiras (FSR), member since February 2015
Experimentalist in the realm of the CMS experiment at LHC, Geneva. I am studying processes involving single top quarks which provide direct probes of electroweak interactions. The second (2015-2018) operational period of LHC, with an expected luminosity of at least four times greater than its first round, will boost the sensitivity of the associated production of single top quarks with Higgs bosons. Such a process offers a stringent test for the SM predictions and serves as an excellent opportunity for identifying departures from this standard picture. Also, I am performing studies within fast detector simulations, i.e. in the context of CMS FastSim.

I am involved in the following research directions:

Advanced Multi-Variate Analysis for New Physics Searches at the LHC

With the 2012 discovery of the Higgs boson at the Large Hadron Collider, LHC, the Standard Model of particle physics has been completed, emerging as a most successful description of matter at the smallest distance scales. But as is always the case, the observation of this particle has also heralded the dawn of a new era in the field: particle physics is now turning to the mysteries posed by the presence of dark matter in the universe, as well as the very existence of the Higgs. The upcoming run of the LHC at 13 TeV will probe possible answers to both issues, providing detailed measurements of the properties of the Higgs and extending significantly the sensitivity to new phenomena.

Since the LHC is the only accelerator currently exploring the energy frontier, it is imperative that the analyses of the collected data use the most powerful possible techniques. In recent years several analyses have utilized multi-variate analysis techniques, obtaining higher sensitivity; yet there is ample room for further improvement. With our program we will import and specialize the most powerful advanced statistical learning techniques to data analyses at the LHC, with the objective of maximizing the chance of new physics discoveries.

We are part of a network of European institutions whose goal is to foster the development and exploitation of Advanced Multi-Variate Analysis (AMVA) for New Physics searches. The network offers extensive training in both physics and advanced analysis techniques to graduate students, focusing on providing them with the know-how and the experience to boost their career prospects in and outside academia. The network develops ties with non-academic partners for the creation of interdisciplinary software tools, allowing a successful knowledge transfer in both directions. The network studies innovative techniques and identifies their suitability to problems encountered in searches for new physics at the LHC and detailed studies of the Higgs boson sector.

External collaborators: University of Oxford, INFN, University of Padova, Université Blaise Pascal, LIP, IASA, CERN, UCI, EPFL, B12 Consulting, SDG Consulting, Yandex, MathWorks.

Angular asymmetries in ttW production

We take advantage of the large statistics being recorded by the CMS experiment in Run 2 to launch a systematic study of angular asymmetries in the ttW process, which have a potentially large sensitivity to non-SM effects.
In synergy with the CP3 phenomenology group, we aim at reporting our results in a form that can be easily translated in EFT constraints.

Development of a framework for fast simulation of a generic collider experiment: Delphes

Observability of new phenomenological models in High Energy experiments is delicate to evaluate, due to the complexity of the related detectors, DAQ chain and software. Delphes is a new framework for fast simulation of a general purpose experiment. The simulation includes a tracking system, a magnetic field, calorimetry and a muon system, and possible very forward detectors arranged along the beamline. The framework is interfaced to standard file format from event generators and outputs observable analysis data objects. The simulation takes into account the detector resolutions, usual reconstruction algorithms for complex objects (FastJet) and a simplified trigger emulation. Detection of very forward scattered particles relies on the transport in beamlines with the Hector software.

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.

Luminosity calibration of the CMS detector

We contribute to the offline absolute calibration of the luminometry system of the CMS detector, by analysing the dedicated "Van der Meer scan" data at different center-of-mass energies and collision types (p-p, p-Pb, Pb-Pb).

As a related task, we also contribute to the data-driven inference of the true amount of "pile-up" collisions.

External collaborators: CMS Luminosity Physics Object Group.

Search for exotic decays of the Higgs boson to a pair of new light bosons with two muons and two b jets in final states

We search for exotic decays of a Higgs boson to a pair of new light bosons, H->a1a1, where one of the light bosons decays to a pair of muons and the other one decays to a pair of b quarks. Such signatures are predicted in a number of well motivated extensions of the standard model, including the next-to-minimal supersymmetry and generic two Higgs doublet models with an additional scalar singlet.

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.

Tomography of large structures using cosmic-ray muons

The general goal of this project is to develop muon-based tomography (“muography”), an innovative multidisciplinary approach to study geological structures, establishing a strong synergy between geophysics and particle physics.
Muography is an imaging technique that relies on the measurement of the absorption of muons produced by the interactions of cosmic rays with the atmosphere.
Applications span from geophysics (the study of the interior of mountains and the remote quasi-online monitoring of active volcanoes) to archaeology and mining.

We are part of the G-ENDEAVOR network, that brings together particle physicists and geophysicists for the development and exploitation of high-resolution portable detectors.

We plan to make use of the local facilities at CP3 (e.g., the gRPC cosmic test bench) for further hardware developments.
We also participate to the MURAVES collaboration through algorithmic and data-analysis aspects like the implementation of time-of-flight capabilities, the analysis of control data for the optimization of the reconstruction algorithms, and the understanding of physics and instrumental backgrounds by data-driven and simulation techniques.

External collaborators: G-ENDEAVOR network (Japan, Italy, France, UK, Spain, Hungary), MURAVES Collaboration (Italy), INFN (Italy), INGV(Italy).

Top quarks in Heavy Ion collisions and other non-standard LHC datasets

The top quark, being the heaviest known elementary particle, is a powerful tool to test QCD.
The study of top quark pair production in Heavy Ion collisions at the LHC, making use of the dedicated Pb-Pb and p-Pb runs, will open a new road in the investigation of the Quark-Gluon Plasma.
This research project started with the first measurement of top-pair cross section in pp collisions at 5.02 GeV, taking advantage of a "reference run" in Nov.2015 (CMS-TOP-16-015). This measurement, in addition to be useful as a reference for our future measurements in Pb-Pb and p-Pb collisions at the same center-of-mass energy per nucleon, also provides a significant broadening of the lever arm for global PDF fits making use of top-quark data.

External collaborators: Pedro Silva and Marta Verweij (CERN).

Show past projects.
Publications in CP3
Showing 5 publications over 75. Show all publications.
All my publications on Inspire


Search for light bosons in decays of the 125 GeV Higgs boson in proton-proton collisions at sqrt(s) = 8 TeV
Khachatryan, Vardan and others
[Abstract] [PDF]
Refereed paper. 10th January.


Cross section measurement of t-channel single top quark production in pp collisions at sqrt(s) = 13 TeV
CMS Collaboration
[Abstract] [PDF] Most precise measurement of the single-top cross section at 13 TeV. Submitted to PLB
Refereed paper. Public experimental note. 4th October.
First measurement of the top quark pair production cross section in proton-proton collisions at sqrt(s)=5.02 TeV
CMS collaboration
[Full text] CMS Physics Analysis Note TOP-16-015, presented at LHCP2016
Public experimental note. 16th June.
Combination of cross-section measurements of associated production of a single top quark and a W boson at sqrt(s)=8 TeV with the ATLAS and CMS experiments
ATLAS and CMS collaborations
[Full text] ATLAS-CONF-2016-023 and CMS-PAS-TOP-15-019 (double reference, as it is a joint note)
Public experimental note. 24th May.
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.

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