Precision Measurement of the the Fine Structure Constant as a test of the Standard Model*

We will report on our progress to measure the fine-structure constant 𝛼 with improved accuracy to resolve the currently unexplained discrepancy between recent 𝛼 measurements [1,2]. The fine-structure constant 𝛼 characterizes the strength of electromagnetic interactions. Precision measurement of 𝛼 with atom interferometry combined with precision measurement of 𝛼 with electron g - 2 enables one of the most powerful tests of the Standard Model and a broad search for new physics [3,4]. We have built a new five meter atomic fountain that suppresses the most challenging systematics related to the size and quality of the interferometry laser beam. Additionally, we are conducting measurements to experimentally validate our simulations of beam-related systematics by inducing controlled distortions to the interferometer beam. We will report on the status and sensitivity goals of our current measurement campaign.

[1] Parker et al., Science 360, 191-195 (2018)

[2] Morel, et al., Nature 588, 61–65 (2020)

[3] Hanneke et al., Phys. Rev. Lett. 100, 120801 (2008) 

[4] Fan et al., Phys. Rev. Lett. 130, 071801 (2023)