IISER MOHALI

Abstract: The proton radius puzzle arises from the discrepancy between the values of the proton charge radius extracted from electronic and muonic hydrogen spectroscopy. A similar tension has also emerged in helium systems. In this presentation, I will first provide an overview of this puzzle and discuss how measuring the isotope shift by precision spectroscopy of the 2³S - 2³P transition in ultracold helium can contribute to resolving it, as well as its relevance for probing physics beyond the Standard Model. I will then describe how such high-precision measurements are performed using an optical frequency comb and present our work on developing the comb system and minimizing key sources of uncertainty. These efforts aim to enable the most precise measurement of this transition to date.