PT Journal
AU NA64 Collaboration (Andreev, YMea
   Molina Bueno, L
   Tuzi, M
TI First constraints on the Lμ – Lτ explanation of the muon g-2 anomaly from NA64-e at CERN
SO Journal of High Energy Physics
JI J. High Energy Phys.
PY 2024
BP 212 - 15pp
VL 07
IS 7
DI 10.1007/JHEP07(2024)212
LA English
DE Beyond Standard Model; Fixed Target Experiments; Dark Matter
AB The inclusion of an additional U(1) gauge L-mu – L-tau symmetry would release the tension between the measured and the predicted value of the anomalous muon magnetic moment: this paradigm assumes the existence of a new, light Z ' vector boson, with dominant coupling to μand tau leptons and interacting with electrons via a loop mechanism. The L-mu – L-tau model can also explain the Dark Matter relic abundance, by assuming that the Z ' boson acts as a "portal" to a new Dark Sector of particles in Nature, not charged under known interactions. In this work we present the results of the Z ' search performed by the NA64-e experiment at CERN SPS, that collected similar to 9 x 10(11) 100 GeV electrons impinging on an active thick target. Despite the suppressed Z ' production yield with an electron beam, NA64-e provides the first accelerator-based results excluding the g – 2 preferred band of the Z ' parameter space in the 1 keV < m(Z ') less than or similar to 2 MeV range, in complementarity with the limits recently obtained by the NA64-mu experiment with a muon beam.
ER