Recoil Measurements with Levitated Spheres*

The development of optomechanical systems has revolutionized the detection of tiny forces over the past few decades. As such technologies reach (and ultimately surpass) quantum measurement limits, they can enable fundamentally new sensors for a variety of applications in nuclear and particle physics. As a proof-of-principle demonstration, I will describe the detection of individual nuclear α decays through the mechanical recoil of the entire micron-sized object in which the decaying nuclei are embedded. By monitoring the motion of an optically trapped microparticle in high vacuum, the tiny recoil of the microparticle (which is >10¹² times more massive than the emitted α itself) can be detected. These techniques provide a new method for detecting nuclear decays that is sensitive to any particles emitted in the decay, including neutral particles that may otherwise evade detection. I will describe how extensions to these techniques can enable extremely sensitive searches for sterile neutrinos or other dark sector particles that may be emitted in nuclear decays.