Z Bosons to Lepton Pairs: Why Equal for All?

  • Level: Graduate 
  • Thread starter DuckAmuck
  • Start date
  • Tags Tags
    Lepton
1 reply · 3K views · last reply
DuckAmuck
Messages
238
Reaction score
40
Hi guys,
Quick question:
Why is the branching ratio of Z bosons into a lepton-antilepton pair equal for all leptons?
Is it not dependent on mass?
Thanks
DA
 

Discussion

The Z coupling to leptons is universal. The Z is much heavier than even the heaviest leptons, so phase space effects are tiny.