POSITRONIUM
– SCI & TECH
News:
In a first, CERN
scientists carry out laser cooling of Positronium
What's
in the news?
●
For the first time, an international team
of physicists from the Anti-hydrogen Experiment - Gravity, Interferometry,
Spectroscopy (AEgIS) collaboration has achieved a breakthrough by demonstrating
the laser cooling of Positronium.
Positronium:
●
Positronium, comprising a bound electron (e-) and positron (e+),
is a fundamental atomic system.
○
The matter, which forms the world around
us, consists of atoms, the simplest of which is hydrogen.
○
This is made up of a positively-charged
proton and a negatively-charged electron.
●
Positronium, on the other hand, consists
of an electron and its antimatter equivalent, a positron.
●
It was first detected by scientists in the
US in 1951.
Properties
of Positronium:
1.
Varieties:
●
There are two forms of positronium based
on their spins such as
○
Ortho-positronium (o-Ps)
○
Para-positronium (p-Ps)
2.
Spin States:
●
Ortho-positronium:
Spins of the electron and positron are parallel (triplet state).
●
Para-positronium:
Spins are anti-parallel (singlet state).
3.
Lifetime:
●
Positronium has a very short lifetime,
typically on the order of 142 nano
seconds, before annihilating into gamma rays.
4.
Annihilation:
●
When positronium annihilates, it produces
two or three gamma-ray photons with energies of 511 keV each, as the total rest
energy of the electron-positron pair is converted into photons.
5.
Mass:
●
Its mass is twice the electron mass, and it is considered a pure leptonic atom.
Go
back to basics:
AEgIS
Initiativec:
Timeline:
●
The AEgIS experiment was formally accepted
by CERN in 2008, with construction
and commissioning continuing through 2012-2016.
Team:
●
Physicists representing 19 European and one Indian research group
from the AEgIS collaboration announced this scientific breakthrough.
Experiment
Location:
●
The experiment was conducted at the
European Organization for Nuclear Research (CERN) in Geneva, Switzerland.
Significance:
●
This experiment serves as a crucial
precursor to the formation of anti-hydrogen and the measurement of Earth’s
gravitational acceleration on antihydrogen in the AEgIS experiment.