Muonium spectroscopy

Test of CPT and Lorentz Invariance from Muonium Spectroscopy... 

Fig. 4 Present plans for an improved laser system for positronium and muonium spectroscopy.

In the following section new results on muonium spectroscopy are presented. Muonium (y e ) is a hydrogen-like atom consisting of two leptons. It provides an ideal system to determine muon properties and measure muon-electron interactions. is one of... 

Hughes, V.W. (1998). High precision spectroscopy of positronium and muonium. Adv. Quant. Chem. 30 99-123. 

Fig. 1. Muonium energy levels for states with principal quantum numbers n = 1 and n = 2. The indicated transitions could be induced to date using modern techniques of microwave or laser spectroscopy. High accuracy has been achieved for the indicated transitions which involve the ground state. The atoms can be produced very efficiently only in the Is state...

Beyond atomic spectroscopy muonium renders the possibility to search directly and sensitively for yet unknown interactions between the two charged leptons from two different generations. Among the mysteries observed for leptons are the apparently conserved lepton numbers. As a matter of fact, several distinctively different lepton number conservation schemes appear to hold, some of which are additive and some are multiplicative, parity-like. Some of them distinguish between lepton families and others don t [46,47,48,49,50]. No local gauge invariance has been revealed yet which would be associated with any of these empirically established laws. Since there is common believe [51] that any discrete conserved quantity is connected to a local gauge invariance, a breakdown of lepton number conservation is widely expected, particularly in the framework of many speculative models. 

A major advantage of facilities with significantly increased muon fiux would be the possibility to use novel experimental techniques which could not be exploited so far [74] like, e.g. the use of cw lasers for optical spectroscopy or an old muonium approach for a new generation M-M search. Further, a wider class of muonic atoms would be become accessible for precision spectroscopy [75] beyond the already started laser investigations of muonic hydrogen [76]. 

---