NADJA STROBBE
Particle physicist working on the CMS experiment
Assistant Professor at the University of Minnesota
BIO
I've always been curious about the world around me, and was already very interested in how the universe works as a child. I was particularly fascinated by stars and the night sky. Throughout my teenage years, I devoured all the astronomy books in the local library, and then moved on to books on other physics topics. One of those books introduced me to particle physics. Instantly, I was intrigued and wanted to learn more about it. I went on to study Physics & Astronomy at Ghent University. After having a great time as a summer student at DESY, performing an analysis using data from the HERMES detector, I decided to fully focus on particle physics for my Master's, and later my PhD. To this day, I remain extremely passionate about physics, and I'm grateful for the opportunity to make exploration my day job.
RESEARCH TOPICS
Since I first joined CMS in 2010, I have focused my efforts on searches for new physics, in particular searches for top squarks and gluinos in a multitude of final states. The existence of these new particles is motivated by supersymmetry. The searches themselves, however, are topology based, and are therefore sensitive to a wider range of new physics models.
SEARCH FOR TOP SQUARKS WITH RPV OR STEALTH DECAYS
CMS SUSY Group (2017 - present)
Conceptualized and started new analysis effort, leading a team of 3 scientists and 3 students
Develop and employ state-of-the-art analysis techniques such as top quark tagging using deep learning
Design and validate background estimation method for this challenging final state of many jets and no missing
transverse momentum
SEARCH FOR TOP SQUARKS IN THE ALL-HADRONIC FINAL STATE WITH TOP QUARK TAGGING
CMS SUSY Group (2015 - 2017)
Led team of 15 people, with focus on defining overall analysis strategy
Resulted in three public results (two as main editor) using 13 TeV data (2015, Summer 2016, 2016)
Developed estimation method for the Z → νν̄ background
Developed improved top quark tagging algorithm that can tag any number of top quarks, with good efficiency
across the top quark pT spectrum
SEARCH FOR NEW PHYSICS WITH BOOSTED W BOSONS
CMS SUSY Group (2013 - 2015)
Investigate and apply jet substructure techniques to identify highly boosted W bosons
Define and study signal and control regions in terms of object requirements and binning in the razor variables
Use novel approach to automatically account for correlations between systematic uncertainties across search bins by sampling all systematic uncertainties simultaneously
DETECTOR EXPERIENCE
Without state-of-the-art detectors it would be impossible to produce qualitative physics results. This includes discoveries of new particles, such as the Higgs boson discovery in 2012, as well as precise measurements of known processes. If we are to discover any new particles that might be out there, it is of paramount importance that we invest time and effort into making our detectors the best they can be.
Since starting my postdoc at Fermilab, I have taken on various leading roles in the context of the Phase 1 upgrade of the CMS Hadron Calorimeter, in particular regarding the readout electronics for the Barrel and Endcap sectors. Below I list some of the highlights.
Going forward, I am excited to join the next batch of detector upgrades ("Phase 2") in preparation for the High Luminosity LHC running period. These upgrades will be crucial to keep up with the increased data delivery rate and associated levels of radiation.
QUALITY CONTROL OF THE HB READOUT BOARDS
I led a team of 15 people - postdocs, and (under)graduate students - to perform quality control and calibration of the production readout electronics for the HCAL Barrel (Summer 2018)
I led a small team of graduate students in testing the prototype readout electronics for the HCAL Barrel (2017–2018)
CHARACTERIZATION AND QUALITY CONTROL OF THE QIE ASIC
The Charge Integration and Encoding (QIE) ASIC integrates charge from the photosensors, digitizes that charge, and encodes it.
I characterized all 45k QIE10 & QIE11 chips used in the upgrade of the HCAL Barrel, Endcap, and Forward calorimeter
I worked closely with engineers and technicians to set up the test stand, and supervised three graduate students
LEAD BEAM TEST FOR HCAL ENDCAP AND BARREL
I coordinated the beam test for the HCAL Endcap and Barrel at the H2 beamline at CERN (Summer 2017), leading a team of >40 people
This beam test was crucial for our understanding of the performance of the Silicon Photomultipliers (SiPM) in preparation
for the full installation of the HE Phase 1 upgrade
RADIATION TEST AT CHARM
I was the coordinator of 2 radiation tests for the readout electronics at the CHARM mixed field facility at CERN (2015, 2016)
LEADERSHIP
CMS SUSY ANALYSIS COMBINATION COORDINATOR
Sep 2018 - present
Form comprehensive strategy for final “legacy” Run 2 SUSY publications
Coordinate grand joint analyses across various final states and working groups
Obtain optimal sensitivity for important SUSY models
5–8 joint analyses, each comprised of 3–5 individual analyses
Lay foundation for Run 3 program by identifying uncovered regions of parameter and phase space
CONVENER OF CMS SUSY MC GROUP
Jan 2015 - Dec 2015
Coordinate the production of Monte Carlo simulation samples for signal and backgrounds for the SUSY group
Provide tools related to MC production to the SUSY analysis teams
Liaison between SUSY group and other CMS Physics groups, mainly in regard to signal interpretation
EDUCATION
Ghent University, Belgium
PHD IN PHYSICS
Oct 2011 - May 2015
Supervisors: Prof. Dirk Ryckbosch & Dr. Michael Tytgat
Thesis: The Razor Boost analysis – Another step in the hunt for new physics at CMS
MSC PHYSICS & ASTRONOMY
Oct 2009 - Jun 2011
Supervisor: Dr. Michael Tytgat
Thesis: Event selection optimization for bjets plus lepton supersymmetry searches with the CMS detector
BA PHYSICS & ASTRONOMY
Oct 2006 - Jun 2009
LET’S CONNECT
Nadja Strobbe
Physics & Nanotechnology Building
115 Union Street SE
Minneapolis, MN
