Projects
Research Projects
Current investigations and future directions.
Antimatter Physics
Positronium PhysicsGravitational Behavior of Positronium
Probing the fundamental interaction between matter and antimatter.
Project Aim
To measure the effect of Earth's gravitational force on the positronium atom (Ps) by extending its lifetime via Rydberg excitation and observing its fall.
Motivation
Addressing the century-old mystery: Does antimatter fall like matter? This project pioneers Ps as an alternative to antihydrogen for testing the Weak Equivalence Principle.
Methodology
A dual approach using laser manipulation for long-lived Ps atoms and a J-PET based detection system to reconstruct annihilation vertices with high precision.
Experimental Approach
Phase I: Interferometry
In the first phase, Ps atoms will be created in the PsICO positron beam at AML. We employ laser cooling and excitation to a metastable Rydberg state, extending the lifetime significantly.
A deflectometer/interferometer system consisting of three equally spaced gratings will measure the inertial forces. The first two gratings create a fringe pattern on the third. This pattern is scanned with sub-nanometer accuracy using a piezo nanopositioning system. By comparing annihilation probabilities on the stopper versus the grating, we determine the strength of the gravitational force.
Phase II: Detection
The second phase involves a sophisticated detection system to reconstruct the vertices of Ps atoms annihilating at the grating or stopper.
We will construct four modular detection units leveraging the expertise of the J-PET collaboration. Each unit consists of multiple plastic scintillators read out by Silicon Photomultipliers (SiPMs). Signal acquisition is entirely FPGA-based, capable of handling high count rates, allowing us to separately register annihilation photons from the grating and the stopper.
Expected Impact
This project aims to provide the first direct measurement of the gravitational effect on positronium. By combining laser physics, particle detection, and digital signal processing, this facility will pave the way for new tests of fundamental physics in the pure leptonic sector, offering insights into the nature of gravity and the matter–antimatter balance.
Project Team
Piyush Pandey
PhD Student (2024) Focus: Simulation & detector construction.
Co-supervised by Dr. S. Sharma.
The Virtual Laboratory
Simulate the experiment. Control the Laser Excitation and the unknown Antimatter Gravity ($\bar{g}$) to see how Positronium behaves in the beamline.
Content in Preparation
Details regarding Antiproton and Antihydrogen experiments will be updated soon.
J-PET
Content in Preparation
Details regarding J-PET related projects will be updated soon.