Does
the World spin right (or left)?
What have in common Venetian gondola, celtic stone,
time arrow and anti-matter? They are all slightly asymmetric.
The
Matter (negative electrons) and anti-matter
(positive electrons, i.e. positrons) seem to
be perfectly symmetric.
The first surprise came in 1957 from somewhat ephemeral (i.e. difficult
to detect) particles called neutrinos. It turned
out, that they turn-around
only in one direction.
If the charge of neutrino is opposite, it rotates in opposite direction.
It seems that the electrical charge (C)
is related to the rotation directions (we call it parity)
in a way that the combination C-P
is maintained.
Next surprise came in 1964, from exotic, but heavy and rather long lived
particles coming to Earth due to cosmic radiation - kaons. It was observed that kaons do not obey to C-P conservation.
C-P is "more left that right".
But the most recent experiments [1,2] show that if we consider together
charge, parity and time, the combination C-P-T is conserved. In other words, it must
be the time which is asymmetric,
compensating the C-P asymmetry.
That's clear: we get older every day!
The C-P asymmetry is small, something
like one part every ten million. But this is sufficient to make time going in one direction and matter being
million times more abundant in Universe than
anti-matter.
In the same way the "celtic stone" or Venetian gondola are slightly asymmetric but they turn (the stone)
or get rowed (the gondola) always in one direction.
[1] A. Angelpoulos et al. "A
determination of thr CPT violation paramater Re(d) from semileptonic decay
if strangeness-tagged neutral kaons", Phys. Lett. B444 52 (1998)
[2] F. Abe et al. "MEasuerements of the CP-Violation Parameter sin (2b)
in Bd-J/K Decays", Phys.Rev. Lett. 81 5513 (1998)
