The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN’s Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons.

Aaij, R., Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., et al. (2022). Test of lepton universality in beauty-quark decays. NATURE PHYSICS, 18(3), 277-282 [10.1038/s41567-021-01478-8].

Test of lepton universality in beauty-quark decays

Borsato M.;Calvi M.;Capelli S.;Carniti P.;Fazzini D.;Gotti C.;Martinazzoli L.;Martinelli M.;Meloni S.;Minotti A.;Petruzzo M.;Salomoni M.;Shields E. B.;
2022

Abstract

The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN’s Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons.
Articolo in rivista - Articolo scientifico
Flavour Physics, Standard Model, Lepton Universality
English
15-mar-2022
2022
18
3
277
282
none
Aaij, R., Beteta, C., Ackernley, T., Adeva, B., Adinolfi, M., Afsharnia, H., et al. (2022). Test of lepton universality in beauty-quark decays. NATURE PHYSICS, 18(3), 277-282 [10.1038/s41567-021-01478-8].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

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/10281/396787
Citazioni
  • Scopus 214
  • ???jsp.display-item.citation.isi??? 118
Social impact