Physics · the experiment
Unmask the neutron's weak magnetism
One asymmetry measurement, two unknowns: it's up to you to separate them. Pin down λ with the lifetime, then tune the precision of the measurements up to the threshold of an observation.
1 · One measurement, two unknowns
Beginner
Why couldn't the beta asymmetry alone reveal weak magnetism?
See it: the blue band gathers the (λ, g_M) pairs that explain the measured asymmetry. Move λ until you reach a world without weak magnetism, g_M = 0.
2 · Pin down λ with the lifetime
Intermediate
With r_n = 1.18796, τ_n = 878.36 s and Ft = 3,070.01 s, what does r_n τ_n (1 + 3λ²) = 2 Ft give?
Solve it yourself: move λ until both sides of the relation are equal.
3 · Cross the threshold of an observation
Intermediate
With g_M = 4.47 ± 0.87, how many standard deviations from zero is the result?
The lifetime is known to ±0.43 s, Ft to ±1.90 s. Tune the uncertainty on the measured asymmetry, Ã ≈ −0.11958, until you recover the article's significance.
4 · Pick the next lever
Expert
Shares of the uncertainty on g_M, added in quadrature: Ft ±0.50, lifetime ±0.39, asymmetry ±0.59. To reach 6 σ by improving only one input, which one cannot do it, even if perfect?
Improve Ft only: reduce its uncertainty until the significance reaches 6.0 σ.
Weak magnetism unmasked
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