← All parts of this equation

Equation 58 · Part 4 · The Atlas That Refuses to Close

Symbol β

∣Δx∣=ρM β≈1.16×10−13 m,|\Delta \mathbf x| = \rho_M\,\beta \approx 1.16\times10^{-13}\ \mathrm{m},
β\beta

What this part means

β is one of the signed contributions combined to compute the quantity on the left.

Its job in the formula

β is one of the signed contributions combined to compute the quantity on the left.

The passage around this formula

…wavepacket of electron mass, S = ℏ\hbar/2 , so that ρM\rho_M = ℏ\hbar/(2mem_ec) ≈\approx 1.931×\times10^{-13}\ m\mathrm{m} , essentially half the electron’s reduced Compton wavelength. Boost it transverse to its own spin at β\beta = v/c = 0.6 . The exact centroid shift between the rest-frame observer and the boosted observer is ∣Δx∣=ρM β≈1.16×10−13 m|\Delta \mathbf x| = \rho_M\,\beta \approx 1.16\times10^{-13}\ \mathrm{m}. about a hundred and sixteen femtometres — smaller than a proton’s charge radius, far below anything a position-resolving instrument built from ordinary matter could hope to…

Read this part in the article →

Learn the underlying idea

A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.

Open the illustrated variables: a letter stands for a value guide →

See this notation across published equations →

Sources cited in the article section

These citations provide research context; check each source for the exact claim it supports.