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Homework Help: Calculating the lifetime of a particle

  1. Oct 16, 2012 #1
    1. The problem statement, all variables and given/known data

    A pi meson (pion) and a proton can briefly join together to form a Δ particle. A measurement of the energy of the ∏p system shows a peak at 1236 MeV, corresponding to the rest energy of the Δ particle, with an experimental spread of 120 MeV. What is the lifetime of the Δ?
    A graph is given of the reaction probability as a function of energy, peaking at energy 1236 MeV. There are arrows on both sides of the peak labeled 120 MeV.

    2. Relevant equations

    ΔE*Δt ~ h-bar

    3. The attempt at a solution
    I am mainly unsure as to what an experimental spread is. My guess is that the experimental spread is equal to ΔE, and so the solution is simply (h-bar)/(120MeV), but that seems too simple.
  2. jcsd
  3. Oct 17, 2012 #2


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    Science Advisor
    Homework Helper

    Hi Takuza! :wink:
    Yup … "experimental spread" and "uncertainty" seem to mean the same :smile:
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