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Confusing question

  • Thread starter kcirick
  • Start date
  • #1
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I will put the question in exact wording that the prof gave us:

Homework Statement


A B+ - B- pair is produced in the decay of at Z0. The B then decays to D + X, where X represents some other particles, with a lifetime of 1.638 x 10^12 s. On average how far will the B0 travel before decaying? This is how the lifetime of the B was measured, by measuring the distance from the production vertex to a secondary vertex where it decayed. (M_B0 = 5.279Gev, M_Z0 = 91.188Gev).

Homework Equations


All I can think of that may help me (beside a clearer wording of the question) would be:

[tex] \tau = \frac{1}{\Gamma_{t}} [/tex]
where $\tau$ is the lifetime of the particle and $\Gamma_{t}$ is the decay width.

The Attempt at a Solution


I just don't understand where the B0 comes from in this context? It just appears in the question. Is B0 a combination of B- and B+? How would the hint (at the end of the question, the masses of the particles) be any use if I use the formula in the 2nd part?

Any thoughts?

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
Meir Achuz
Science Advisor
Homework Helper
Gold Member
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The B0 in the question must be a misprint. The PDG gives 1.53 as the B0 lifetime, not 1.638, so I don't think the B0 ever enters the problem.
 
  • #3
54
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Yeah, I asked the prof, and it is a typo... I really dont like it when there is a typo in an assignment.

It was supposed to be [itex]B^{0}[/itex] and [itex]\bar{B^{0}}[/itex] as a decay process of [itex]Z^{0}[/itex].

Thanks for the help anyway!
-Rick
 
Last edited:

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