It is generally known that the particles which compose the atomic nucleus, protons and neutrons (as well as scores of other particles, such as mesons) are made of smaller constituents called "quarks". These quarks are attracted to each other by a force called "color" (it's just a name, no relation to color as we know it).
While quarks and color present some similarities to charged particles
and electricity, they are also different in many important respects.
For instance, instead of the 2 possible charges (positive and
negative) of electricity, color
exhibits 6 possible charges (red, blue, green, antired, antiblue and
anti-green).
Color-neutral objects can be made both by combining a color with it's
anticolor (this is what happens in mesons) or all the 3 colors together
(protons and neutrons are made this way).
However, color presents an additional characteristic which makes
systems interacting via it fiendishly difficoult to study:
Electric fields, while carrying force between charges, are NOT
themselves electrically charged. Color fields, on the other hand,
possess a color charge of their own.
As a result, each part of a color field attracts every other part, and
the field ,if it's sufficiently large (the charges are sufficiently far apart)
, contracts on itself to form a sort of infinitely thin infinitely strong
string.
Therefore, unlike the smooth electric and gravitational fields which just
slowly decrease with distance, color fields behave very much like "perfect"
elastic bands: It's quite easy to move a quark bound by a color
field by a "small" distance, but it seems IMPOSSIBLE to take it out
of the field. If one tries, sooner or later enough energy will be spent
to create new quarks, and, instead of a free quark, one will end up with
2 different quark systems.
Because of this characteristic, studying strongly interacting systems
is very difficoult. While we know the fundamentals of the nuclear force,
we are still very far accounting how it gives rise to the particles and
combinations of particles that we see in nature.
One of the main difficoulties of such experiments, however, is that
it is still not clear what is the best way to observe and study quark
gluon plasma is. We cannot really look into it directly, and can only
study what comes out of the collision.
It's as if we lived in a world
which was too cold to allow liquid water to be formed for more than an
instant.
To study the properties of liquid water, we'd have to intensely squeeze
two snowballs so that,
for a few instants, the center would be compressed enough to liquify water
for a few seconds. Afterwards, the water would freeze again, and we'd
have to use the ice so formed to study what the water was like for that
instant before it froze.
And here ,finally, is the area of my work. I am looking for ways in which we can study matter which underwent a transition to quark gluon plasma but then reverted to it's normal state again. Specifically, I am studying what the characteristics of the re-formed normal matter can tell us about the reactions which took place there before the observation.
In contrast, in an ensemble of "normal" particles interacting, collisions which produce Omegas (or, even worse, anti-omegas, which by baryon conservation will have to be produced in pairs with omegas) are very infrequent since these particles are Very heavy and require a lot of energy to be produced.
Hence, one expects an enhancement of strange particles and antiparticles had deconfinement occurred. This enhancement should, by the arguments above, increase with the strangeness content and heaviness of the particle.
My work consists in studying and developing quantitavie predictions based
on this model.
I use statistical mechanics and kinetic theory applied to particles moving
at relativistic velocities to calculate how likely is the production
of each particle type in a rapidly hadronizing medium whith an isotropic
distribution of "free" quarks.
This paper was recently selected for IOP Select, a collection of articles appearing Institute of physics Journals chosen for
The Yale group, other than include some really cool people, mantains an excellent webpage on heavy ion physics.
Where the experimental action is happening:
Finally, there has been speculation, both in the scientific community and
in the media, that these experiments could lead to... the end of the world!
Several "Catastrophic scenarios" (the formation of mini black holes
"voracious strange matter", the formation of a vacuum more stable than
our own) have been proposed in which heavy ion collisions initiate
a chain reaction which will end up "eating" the matter around it, ie
the whole earth.
You would be surprised to know that physicists in fact ARE sane enough NOT to desire something like that to happen. And that the only reason we are continuing activity in this field is that we are damn sure these catastrophic scenarios are IMPOSSIBLE. If you want to find out more...
Academic papers on the subject, written by leading specialists, are available here and here
More or less hysterical articles in the media:
