After the discovery
of meson (m
) i.e. "intermedier"
, heavier 207* times
than electron, but much more lighter than proton, it was decided to name
light particles as leptons or lighters.
Leptons can be found
in Greece - you can take one of them as a souvenir**.
Lepto(n)
It's a bit unlucky
but third lighter - tau (t), is twice heavier
than proton, neutron and many others heaviers or hadrons.
Do not try to lift
up t lepton, you will squeeze your fingers!
* Lepton's masses (1990)
me=0,51099906±0.000000015 MeV, lifetime > 2·10
22 years
mm=105,658387±0.000034 MeV, lifetime
(2,19703±0,00004)·10-6 s
mt=1784,1+2.7
-3.6 MeV, lifetime (0,303±0.008)·10-12 s
** Organizers appology, but Bank of Greece retracts 1 lepto coins from currency
and it was not possible to deliver a sufficient amount of
leptons.
Masses of presented here m lepton, proton and
neutron corresponds exactly to the proportions to 1 cent lepton e (2.29g).
t
"Lepton"
in the present shape is slighty heavier than it should be from comparison
to e
lepton
.
