I read about a technique called b-tagging in which one can check if a b meson was produced in a collision by looking for a jet which has a secondary vertex within it. The reason is that b mesons are long lived, so that meson would travel a bit before decaying, hence the secondary vertex. Why are b meson long lived? And why can't we do this with other kind of quarks, like strange or charm? Thank you!

  • $\begingroup$ Is your question about b-tagging, or a very different one: why are the lifetimes of K/D/B mesons, in seconds, $10^{-8}~/ ~ 10^{-14}~/ ~ 10^{-12}$, respectively? $\endgroup$ – Cosmas Zachos Oct 22 at 20:23

The reason is that b mesons are long lived

That is not the reason b-taggin is interesting and is used. There is also c tagging,and the lifetimes are similarly short, notlong.

Heavy-flavourjet identification exploits the properties of the hadrons originated in the jet to discriminate heavy flavour(b-,c-) initiated jets from those arising from light partons

From wikipedia

b-tagging is important because:

  1. The physics of bottom quarks is quite interesting; in particular, it sheds light on CP violation.
  1. Some important high-mass particles (both recently discovered and hypothetical) decay into bottom quarks. Top quarks very nearly always do so, and the Higgs boson is expected to decay into bottom quarks more than any other particle given its mass has been observed to be about 125 GeV. Identifying bottom quarks helps to identify the decays of these particles.
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