Measurement of the Formation Rate of Muonic Hydrogen Molecules

Understand

Background: The rate \lambda_pp\mu\ characterizes the formation of pp\mu\ molecules in collisions of muonic p\mu\ atoms with hydrogen.

• In measurements of the basic weak muon capture reaction on the proton to determine the pseudoscalar coupling g_P, capture occurs from both atomic and molecular states.
• Thus knowledge of \lambda_pp\mu\ is required for a correct interpretation of these experiments.
• Purpose: Recently the MuCap experiment has measured the capture rate \Lambda_S from the singlet p\mu\ atom, employing a low density active target to suppress pp\mu\ formation (PRL 110, 12504 (2013)).