Detection of Scalar Particles with Predominant Coupling to Muons in the NA62 Experiment

Evidence for new physics has led to many recent experiments in low energy physics, particularly the neutrino and dark matter sectors [1]. The production of exotics such as dark photons and axions could explain discrepancies in the theoretical predictions and empirical measurements of parameters such as the anomalous muon magnetic moment and muonic hydrogen lamb shift [1]. This project explores the production of scalar particles that are predominantly coupled to muons through bremmstrahlung interactions of sufficiently energetic muons in the NA62 experiment at CERN. Using the Improved Weizsacker-Williams (IWW) approximation, I calculated the sensitivity of NA62 to the scalar’s mass (mS) and the muon coupling (gµ) for two different models: model A, in which the lepton coupling to the scalar is proportional to the mass of the lepton, and model B, in which the scalar only couples to muons. Although my approximations for the sensitivity region of NA62 for model A indicate that NA62 should be sensitive to new regions of the {ms, gµ} parameter space, my most recent sensitivity plot that incorporates the acceptance of the scalars’ daughter particles exhibits lower sensitivity than expected. Nonetheless, the sensitivity plots that this work produces have calculations of unprecedented detail for model A, and will be the first-of-its-kind for model B.