Experimental Neutrino Physics and Dark Matter Search

My past research work has mainly focused on experimental studies on neutrino properties, this includes measuring the neutrino oscillation parameters and searching for the fourth type neutrino, the sterile neutrino. Although the Standard Model of particle physics has proved to be a remarkably resilient theory, we know that it does not give a complete description of the observable universe. For my dissertation work, I have been testing models which describe the physics beyond the standard model. In the next step of my research career, I would like to gain experience in designing precision experiments to test our knowledge of the universe, to extend the present knowledge and make new discoveries.

Standard three-flavor neutrino oscillations have been well explained by a wide range of neutrino experiments. But there are anomalous results, such as electron-antineutrino excesses seen by LSND and MiniBooNE which do not fit the three-flavor paradigm. This can possibly be explained by an additional fourth sterile neutrino at a larger mass scale than the existing three flavor neutrinos. The NOvA experiment at Fermilab consists of two finely segmented, liquid scintillator detectors, a near and a far detector, operating 14.6 mrad off-axis from the Neutrinos at Main Injector (NuMI) muon-neutrino beam. The Near Detector is located on the Fermilab campus, 1 km from the NuMI target, while the Far Detector is located at Ash River, MN, 810 km from the NuMI target. The NOvA experiment is primarily designed to measure electron-neutrino appearance at the Far Detector using the Near Detector to control systematic uncertainties; however, the Near Detector with L/E in the range 0.1 -1 is well suited for searching for anomalous short-baseline oscillations.

My PhD research is on the NOvA experiment where I performed a search for anomalous τ neutrino appearance due to sterile neutrino oscillations in the NOvA Near Detector. This was the first time this search has been performed at NOvA. I performed the full analysis which includes, developing particle identifiers for the hadronic decay mode of ν_τ Charged Current interactions, optimizing the signal event selection for maximum background rejection and detailed systematic studies for this first analysis of its type. As mentioned before, NOvA is located 14.6 mrad off-axis to NuMI beam axis, where the beam energy peaks at 2 GeV, with neutrinos mainly coming from pions. The NOvA beam has also a second energy peak in which neutrinos are mainly coming from kaons, whose energy is greater than the τ production threshold. I used these high energy neutrinos for this analysis. The main challenge of this analysis comes from the identification of high energy ν_τ Charged Current (CC) signal from a huge ν_μ, ν_e CC and Neutral Current background in the detector. It is not practically possible to identify the τ particle directly since the spatial and time resolution of the detector is much larger than the τ decay length. However, it is possible to identify the τ decay products in the detector. The other challenge is to optimize the sensitivity when including the huge systematic uncertainty arising from various detector and simulation effects. To identify the signal in this analysis, the hadronic τ decay, I developed 3 discriminants using the ROOT toolkit for multivariate data analysis(TMVA).

This work has been presented in major international conferences like Neutrino ‘16 (London, 2016 - poster), International Neutrino Summer School (Fermilab, 2017 - received 2-nd place poster award), Neutrino ‘18 (Germany, 2018 - poster), April Meeting of American Physical Society (Washington DC, January 2016 - talk) and Meeting of Division of Particles and Fields of American Physical Society (Fermilab, April 2017 - poster).

I was an expert in monte-carlo production in NOvA. I have made a significant contributions to the production of data files corresponding to 8×10²⁰ POT needed for the various analyses in NOvA including 2016 and 2017 ν_e appearance, ν_μ disappearance and 2017 Neutral Current disappearance analyses.

In addition to this research work I have also had the opportunity to participate in hardware projects. I have a significant contribution in the quality analysis of the avalanche photodiodes (APDs) used for the replacement of malfunctioning APDs. I am a trained expert in the replacement of malfunctioning electronics on the detector. Additionally I participated in the operation of the experiment by taking control room shifts.

My During my postdoctoral tenure at the Vrije Universiteit Brussel (VUB), my research was primarily focused on testing the sterile neutrino hypothesis using neutrinos produced at the BR2 nuclear reactor in Mol, Belgium. Anti–electron neutrinos from nuclear reactors provide a powerful tool to investigate potential sterile neutrino oscillations. I worked as a postdoctoral fellow in the SoLid neutrino experiment, situated at the BR2 reactor, where the main objectives were to search for sterile neutrino oscillations and to measure the anti-electron neutrino flux and energy spectrum. My contributions included leading the background studies using the complete reactor-off Phase-1 dataset for simulation tuning. I was also actively involved in oscillation fit and sensitivity studies for the sterile neutrino analysis. Additionally, I played a key role in the heavy neutral lepton (HNL) analysis, where I introduced a Machine Learning (ML)-based signal discriminant for the first time in the experiment. I also contributed to the calibration of the detector’s electromagnetic scintillation signal.

In addition to my research contributions, I served as the Data Manager for the SoLid experiment, overseeing the organization, access, and integrity of the experiment’s data. I also led the Data Quality and Operations working group for over three years, coordinating daily detector monitoring, data validation, and run planning activities. These roles required strong collaboration, technical oversight, and leadership to ensure the reliability and efficiency of data collection and processing across the collaboration.

I am currently a Research Scientist at Virginia Tech, actively contributing to the DarkSIDE-20k experiment — a cutting-edge initiative designed to detect dark matter using liquid argon as the target medium. My work is primarily focused on the hardware development aspect of the project, where I lead efforts in designing, optimizing, and precisely calibrating complex components essential for the experiment’s operation. This role also involves ensuring the seamless integration of these systems within the larger experimental framework. My recent promotion and ongoing contributions reflect a continued commitment to advancing experimental particle physics and detector technology.

Future Research Interests

The next few years are pivotal with a range of experiments being conceived to improve the understanding and make new discoveries. Working on the future neutrino experiment would be an ideal opportunity to make my contribution. I am more excited than ever to put my skills to any present or future experiment and help the field strive to reach a better understanding of the laws of nature.

During my time at Fermilab, as a member in one of the world leading long-baseline neutrino experiments, I became aware of the exciting neutrino physics programs at the Lab and I would love the opportunity to expand my horizon in this area. The neutrino sector is one of the aspects of the Standard Model (SM) and Beyond Standard Model (BSM) where there are still many unanswered questions and puzzles.