1971-1977: Tau - The book of science

Tau
Time dilation / length contraction
Bremsstrahlung
Symbols
Commentary

Yung-su Tsai, Martin Lewis Perl particle physics

Tau

Electron, muon, and tau
carry exactly the same charge,
and the same spin,
but have progressively larger masses
and shorter lifetimes.
Too bad making tau
is not very practical, unless
you have your own positron-electron accelerator.

Time dilation / length contraction

People wondered how muons and tau
could penetrate solids as deep as they do,
considering their ultra-short lifetimes;
however, FitzGerald and Einstein
had already explained length-contraction
and time dilation.
From its own point of view,
a particle traveling near the speed of light
sees great distances in a small span,
and from our point of view,
a particle traveling near the speed of light
appears to age extremely slow.

Bremsstrahlung

Its energy has to go somewhere,
so when a fast charged particle
is decelerated or deflected,
it emits “braking radiation”—
like the noise of a crash landing.

Symbols

For electron, e.
For muon, the Greek μ (mu).
For tau, the Greek τ
short for τρίτον meaning “third”—
(tau, rho, iota, tau, omicron, nu).

Like the tau particle, I am the third Frederick in my paternal line—my grandfather, Frederick Lee, whom I shall designate with the symbol “Λ” (Lambda), my father, Frederick James, otherwise Frederick “Ζ,” and me, Frederick “Τ.”

See also in The book of science:

1889—Length contraction—George Francis FitzGerald
1897—Electron—Joseph John Thomson
1905—Special relativity—Albert Einstein
1932—Antimatter—Paul Dirac, Carl David Anderson
1932—Phonon—Igor Tamm
1932-1951—Positronium—Carl David Anderson, Stjepan Mohorovičić, Martin Deutsch
1934,1947—Meson—Hideki Yukawa, Cecil Powell, César Lattes, Giuseppe Occhialini
1935—Majorana fermion—Ettore Majorana
1936—Muon—Carl David Anderson, Seth Neddermeyer
1956—Neutrino—Wolfgang Pauli, Frederick Reines, Clyde Cowan
1960—Muonium—Vernon W. Hughes

Readings on wikipedia: