Theories beyond the standard model often predict the existence of an additional neutral boson, the Z′. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z′ in the process e+e-→μ+μ-Z′ and of a lepton-flavor-violating Z′ in e+e-→e±μZ′. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an Lμ-Lτ theory, into upper limits on the Z′ coupling constant at the level of 5×10-2-1 for MZ′≤6 GeV/c2.
Search for an Invisibly Decaying Z′ Boson at Belle II in e+e- →μ+μ- (e±μ) Plus Missing Energy Final States / Belle II, Collaboration; Aloisio, A.; Campajola, M.; De Nardo, G.; Di Capua, F.; Giordano, R.; Merola, M.; Russo, G.; Et, Al.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 124:14(2020). [10.1103/PhysRevLett.124.141801]
Search for an Invisibly Decaying Z′ Boson at Belle II in e+e- →μ+μ- (e±μ) Plus Missing Energy Final States
Aloisio, A.;Campajola, M.;De Nardo, G.;Di Capua, F.;Giordano, R.;Merola, M.;Russo, G.;
2020
Abstract
Theories beyond the standard model often predict the existence of an additional neutral boson, the Z′. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z′ in the process e+e-→μ+μ-Z′ and of a lepton-flavor-violating Z′ in e+e-→e±μZ′. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an Lμ-Lτ theory, into upper limits on the Z′ coupling constant at the level of 5×10-2-1 for MZ′≤6 GeV/c2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
