Searching for Majorana neutrinos at a same-sign muon collider

Majorana properties of neutrinos have long been a focus in the pursuit of possible new physics beyond the standard model, which has motivated lots of dedicated theoretical and experimental studies. A future same-sign muon collider is an ideal platform to search for Majorana neutrinos through the lepton number violation process: <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msup><a:mi>μ</a:mi><a:mo>+</a:mo></a:msup><a:msup><a:mi>μ</a:mi><a:mo>+</a:mo></a:msup><a:mo stretchy="false">→</a:mo><a:msup><a:mi mathvariant="normal">W</a:mi><a:mo>+</a:mo></a:msup><a:msup><a:mi mathvariant="normal">W</a:mi><a:mo>+</a:mo></a:msup></a:math>. Specifically, this t-channel kind of process is less kinematically suppressed and has a good advantage in probing Majorana neutrinos at high mass regions up to 10 TeV. In this paper, we perform a detailed fast Monte Carlo simulation study by examining three different final states: (1) pure leptonic state with electrons or muons, (2) semileptonic state, and (3) pure hadronic state in the resolved or merged categories. Furthermore, we perform a full simulation study on the pure leptonic final state to validate our fast simulation results. Published by the American Physical Society 2024