The L & mu; - L & tau; extension of the standard model predicts the existence of a lepton-flavor-universality -violating Z0 boson that couples only to the heavier lepton families. We search for such a Z0 through its invisible decay in the process e thorn e- & RARR; & mu; thorn & mu;-Z0. We use a sample of electron-positron collisions at a center -of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7 fb-1. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3 x 10-3 at low Z0 masses to 1 at Z0 masses of 8 GeV/c2.

Search for an Invisible Z′ in a Final State with Two Muons and Missing Energy at Belle II

Ganiev, E.;Lanceri, L.;Manfredi, R.;Raiz, S.;Vitale, L.;
2023-01-01

Abstract

The L & mu; - L & tau; extension of the standard model predicts the existence of a lepton-flavor-universality -violating Z0 boson that couples only to the heavier lepton families. We search for such a Z0 through its invisible decay in the process e thorn e- & RARR; & mu; thorn & mu;-Z0. We use a sample of electron-positron collisions at a center -of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7 fb-1. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3 x 10-3 at low Z0 masses to 1 at Z0 masses of 8 GeV/c2.
File in questo prodotto:
File Dimensione Formato  
PhysRevLett.130.231801.pdf

accesso aperto

Tipologia: Documento in Versione Editoriale
Licenza: Creative commons
Dimensione 7.21 MB
Formato Adobe PDF
7.21 MB Adobe PDF Visualizza/Apri
ZprimeInvisible_supplementaryMaterial.pdf

accesso aperto

Descrizione: Supplementary material
Tipologia: Altro materiale allegato
Licenza: Creative commons
Dimensione 3.75 MB
Formato Adobe PDF
3.75 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/3068360
Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 0
social impact