Constraints on muonium-antimuonium conversion

Abstract

We discuss a simple model in which muonium-antimuonium conversion can occur at a level around the recent experimental bound but the process ju-> ey is strictly forbidden. Measurements of the anomalous muon magnetic moment and high-energy Bhabha scattering e*e~->e*e~ together provide an indirect and interesting constraint on the conversion. The model predicts anomalous events ep-+e~niiX at high-energy ep colliders.

Bileptons: present limits and future prospects

“…Constraints on bileptons from Bhabha scattering (e + e − → e + e − ) have been calculated in Refs [25,27,32,66]. However, bounds on four fermion operators of the form (ēΓe)(f Γf ) (f here is an e, µ or τ ) have been calculated by the JADE and TASSO collaborations from PETRA data [67,68], and it is these stronger constraints that we quote.…”

“…5. This has been considered by many people [10,14,17,18,23,25,28,29,30,31,35]; [29] also studied muonium hyperfine splitting and [30] have studied this in a magnetic field. As yet no such events have been observed and the most stringent 90% C.L.…”

“…The contribution to g − 2 of the muon from bileptons, or generic bosons from beyond the standard model, has been computed in [14,17,20,25,28,29,34,36,57].…”

Vector- and scalar-bilepton pair production in hadron colliders

“…They were not observed, but the data extracted from the LEP II experiments can be used to established limits on the vector-bilepton masses around 100 GeV [11]. More exactly, from muonium-antimuonium conversion experiments [12,13,14], the upper bound for the ratio of double-charged vector-bilepton-lepton coupling to its mass is of order 0.27 TeV −1 with 95% C.L. In the case of the double-charged scalar-bilepton, CDF and DØ establish the lower bound for the bilepton mass in the range 110 − 150 GeV [15,16,17,18] with 95% C.L., from the exclusive bilepton decay into left-handed eτ , µ τ and µ µ pairs by considering the left-right model, the SM with a Higgs triplet and the little Higgs model.…”

Muonium hyperfine structure and the decayμ+→e++ν¯Fujii1, Mimura2, Sasaki3 et al. 1994Phys. Rev. D440480View full textAdd to dashboardCite

“…This form is obtained from Eq. (1) [18] . In consequence, we obtain a different value for the transition amplitude < M |H eff |M >= δ/2 in the triplet 1S hyperfine state from the one in the singlet state.…”