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Tests of -decay theory
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Tests of (p e ) Kurie plot for “allowed” Kurie plot for “forbidden” -- Find endpoint energy/momentum Plot --
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Tests of (p e ) If a (allowed) Kurie plot is linear then -- –The transition (decay) is “allowed” which implies is a constant; does not depend on k and/or k. –The extrapolated x-axis crossing (y=0) is at E e = E f known as the endpoint energy. –The slope of the line is -- Weak interaction coupling constant Nuclear matrix element Two unknowns --- c.f., Fig. 9.4
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Tests of (p e ) If a (allowed) Kurie plot is not linear then -- –The transition (decay) is not “allowed” which implies is a not constant; does depend on k and/or k. The decay must be “first forbidden” or “second forbidden” … (see next slide) –A functional correction can be applied to straighten the line and thereby represent the momentum dependence, called the “shape correction” -- (see slide 2) c.f. Fig. 9.5
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Tests of (p e ) Lepton wavefunctions -- “Allowed term” “First forbidden term” “Second forbidden term” etc….
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Tests of “Fermi integral” Can be calculated! c.f., Fig. 9.8 Total decay rate
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Tests of Comparative half-life -- or -- ft-value - or (log 10 ft) value Differences in ft 1/2 must be due to differences in
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Tests of For what nuclear decays might be ~the same? How would you know they were the same? Log ft would be ~same If can be estimated then g can be determined!! 0 + 0 + decays c.f., Table 9.2
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Neutrino mass (Why?) will decrease! Limits on m are ~few eV Need to know everything to a precision/accuracy ~few eV pDpD pepe Need to know nuclear wavefunctions!!
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