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Varied Particle Halflife?

  1. Jul 7, 2012 #1

    I am interested if anyone ever studied if a particle's halflife under different conditions.
    Usually you can see how long a particle lasts by measuring how long it moves at a relativistic speed.

    Has anyone ever tried to experiment and see if having the particle move at a relativistic speed would affect its halflife?

    For example, the neutron is noted to have a halflife of 611.0 ± 1.0 s. I gather this was calculated by measuring the free neutron's distance traveled at a relativistic speed.

    I do understand that it is very difficult to slow down a free neutron from a reaction, but has anyone ever tried to measure free neutron's halflife at a non-relativistic speed?
  2. jcsd
  3. Jul 7, 2012 #2


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  4. Jul 7, 2012 #3


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    For long-living particles like the neutron, the common method is to put a bunch of neutrons in a box and to measure the (time-dependent) activity.

    Muon lifetimes can be measured with stopped muons (=> at rest in the lab frame) and compared with moving muons (from cosmic rays, or in particle collider experiments).

    In particle colliders, the energy and therefore the gamma factor of the particle varies, therefore you can measure the predicted time dilation in a wide energy range with high precision. Needless to say that measurements agree with theory ;).
  5. Jul 7, 2012 #4


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    LiteHacker, According to Wikipedia, the best current measurements of the neutron lifetime are made using ultracold neutrons (about 7.6 m/s)
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