Experimental constraints on left-right symmetric models from muon decay

Area of Science:

• Particle Physics
• High-Energy Physics
• Standard Model

Background:

• Muon decay is a fundamental process in particle physics.
• Testing the Standard Model (SM) in purely leptonic processes provides stringent constraints.
• Extensions to the SM are explored through precision measurements.

Purpose of the Study:

• To conduct a precise measurement of the energy-angle spectrum of positrons from muon decay.
• To simultaneously measure muon decay parameters ρ, δ, and P(μ)(π)ξ.
• To test the Standard Model and constrain extensions using leptonic decay data.

Main Methods:

• Utilized the TWIST detector for high-precision measurements.
• Analyzed the energy and angular distribution of decay positrons.
• Performed simultaneous fits of muon decay parameters.

Main Results:

• Completed a new measurement of the positron energy-angle spectrum from highly polarized muon decay.
• Obtained improved limits for extensions to the Standard Model.
• Established constraints for the generalized left-right symmetric model: |(g(R)/g(L))ζ|<0.020 and (g(L)/g(R))m(2)>578 GeV/c(2) at 90% C.L.

Conclusions:

• The measurement provides a stringent test of the Standard Model in a purely leptonic process.
• The results offer improved constraints on new physics beyond the Standard Model.
• This precision measurement contributes to the ongoing search for physics beyond the Standard Model.