Experimental Particle Physicist
Working on the LHCb Experiment
As a Post-Doc @ EPFL
Details will soon to be added
Traditionally, ATLAS uses the measured calorimeter energy and momentum to reconstruct the mass of the particles. Masses of long lived particles that do not leave large energy deposits inside the ATLAS calorimeters cannot be properly reconstructed this way. Charged particles leave ionization energy as they pass through the inner detector of ATLAS. The lost ionization energy is proportional to the speed of ionizing particles though the Bethe-Bloch equation. ATLAS inner detector measures both the momentum and this lost ionization energy which then can be used to extract the mass of ionizing particles that pass through the LHC. In this project me and my colleagues are using this "mass reconstruction through the ionization energy" method to identify the long lived particles that do not leave large energy deposits inside the ATLAS calorimeters. This project holds big challenges due to using non-standard ATLAS objects, and the background composition being composed of secondary SM effects that would need unreasonably large statistics to simulate through traditional MC methods.
In 2029, the Large Hadron Collider (LHC) will re-start it's operation under the name of High Lumi LHC (HL-LHC), and HL-LHC would be able to provide around $\sim 200$ inelastic proton-proton collisions per second. In order to be able to handle this many collisions, the ATLAS experiment's inner detector will be upgraded with a new detector called the Inner Tracker (ITk). Between 2019-2025, I have been working hands-on with existing single ITk pixel readout prototype, contributing to the development of the DAQ software for the ITk pixel detector, and testing the existing DAQ hardware. For the ITk DAQ software, I have been working on optimisation the existing calibration software, as well as adding non-existing features to the software like faster threshold scans, TOT-calibration, and ADC sensor (temperature, current sensor in the chip) readouts. On the DAQ hardware side, I have been testing and setting up different Felix DAQ hardware setups at both LBNL and CERN, as well as writing documentation on them. In addition, as of 2022 to 2025, I have been one of the main designers the BCM’ detectors readout software and firmware from scratch, and currently working on TDAQ hardware design as well as module QC.
Certain SUSY signal models predicts long-lived particles that survive long enough to make it into the ATLAS detector or doesn't decay inside the ATLAS detector at all. These particles can be identified in offline analysis, but for this they need to be triggered (to be saved for offline reconstruction) first. The existing ATLAS triggers are not always efficient for this purpose (the signatures may have minimal calorimeter activity or a delayed muon response). For this purpose, I am currently working on a new ATLAS trigger. This trigger aims to identify such events only using the tracks reconstructed inside the inner detector, who are isolated and have high momentum. At the current state, this trigger have a background rate around 2 HZ with a signal efficiency around ~90% over the L1 MET trigger for SUSY STau signals with lifetimes over 10ns. This means, this trigger performs more then 25 better compared to existing triggers, while increasing the background rate only by a small amount.
Quartic and triple gauge boson interaction is a fundamental piece of SM that needs further investigations. These interactions are predicted by the SM and are required in-order to keep the SM Lagrangian's Higgs interactions normalizable. Most important of all, not all of these interactions have been observed yet.
The tri-W production in ATLAS, is produced by these quartic and triple gauge boson interactions. In this research me and my colleagues how found the first evidence of the tri-W production. The analysis covers both fully and semi-leptonic channels. We have first conducted at 8 TeV and then at 13 TeV with a partial dataset. The 8 TeV results were published as the cover of EPJC as the cover in March 2017, and the 13 TeV analysis provided the first evidence for the tri-W production. Currently a new effort is on the way to extend this study to the full 13TeV dataset.
At the newly designed new small wheel (NSW) of the ATLAS detector there are new electronics that needs to be tested and tracked. For this reason we have designed variety of databases, software, and webpage solutions. Till May 2019 I was maintaining the database which I then handed over.
For my masters thesis, I conducted a search on E6 Iso-Singlet quarks proposed by Feza Gursey using the