TY  - JOUR
AU  - Flores-Tlalpa, A.
AU  - Lopez Castro, G.
AU  - Roig, P.
PY  - 2016
DA  - 2016//
TI  - Five-body leptonic decays of muon and tau lepton
T2  - J. High Energy Phys.
JO  - Journal of High Energy Physics
SP  - 185
EP  - 21pp
VL  - 04
IS  - 4
PB  - Springer
KW  - CP violation
KW  - Discrete Symmetries
KW  - Effective field theories
KW  - Precision QED
AB  - We study the five-body decays u(-) -> e(-)e(+)e(-)nu u (nu) over bar (e) and tau(-) -> l(-)l'+l'-nu(tau)(nu) over bar (l) for l, l' = e, u within the Standard Model (SM) and in a general effective field theory description of the weak interactions at low energies. We compute the branching ratios and compare our results with two previous – mutually discrepan – SM calculations. By assuming a general structure for the weak currents we derive the expressions for the energy and angular distributions of the three charged leptons when the decaying lepton is polarized, which will be useful in precise tests of the weak charged current at Belle II. In these decays, leptonic T-odd correlations in triple products of spin and momenta – which may signal time reversal violation in the leptonic sector – are suppressed by the tiny neutrino masses. Therefore, a measurement of such T-violating observables would be associated to neutrinoless lepton flavor violating (LFV) decays, where this effect is not extremely suppressed. We also study the backgrounds that the SM five-lepton lepton decays constitute to searches of LFV L- -> ? l(-)l'+l'(-) decays. Searches at high values of the invariant mass of the l'(+)l'(-) pair look the most convenient way to overcome the background.
SN  - 1029-8479
UR  - http://arxiv.org/abs/1508.01822
UR  - https://doi.org/10.1007/JHEP04(2016)185
DO  - 10.1007/JHEP04(2016)185
LA  - English
N1  - WOS:000411265800003
ID  - Flores-Tlalpa_etal2016
ER  -