Good evening, The movie we're about to see...
will lead us to the discovery of a world
wonderful and charming.
We are in fact to make a journey within
the most famous physics laboratory in the world...
the CERN, the European Center for Nuclear Research.
A journey that will lead us to the borders
of current scientific knowledge.
To the discovery of what are believed to be
the fundamental constituents of the Universe...
Quarks.
And even more, in an attempt to observe closely...
matter as it appeared in the
first moments of the universe.
More than that, we'll see what lies
"Behind the scenes" of this laboratory.
Also, we will look closely at the lifestyle
habits of one of the most bizarre creatures...
the experimental high-energy physicist.
Let's see.
CERN,
Even today it is the largest particle
physics laboratory in the world.
Each year, more than 6,500 scientists from
more than 60 countries...
come to CERN for their research.
Located on the border between France and Switzerland...
it is in fact divided into two distinct sectors.
The North area, entirely in France...
and the west area or site of Meyrin,
located near the city of Geneva.
Founded in 1954, it is surprisingly...
one of the best examples of
international collaboration.
The number of Member States is still growing.
From the original 12 at the birth,
today there are as many as 20.
CERN allows the international scientific community
to explore the fundamental constituents of matter...
and their properties.
Many of the experiments carried out at CERN...
are part of the history of physics.
The original devices are exposed to the public.
But what are actually the elementary particles?
And how do scientists to observe and to study
with these huge devices?
Suppose we observe a fragment of matter.
If we expanded it enough, we would discover
that it is formed by smaller particles, the atoms.
The atoms are complex objects, consisting of a central,
heavy core, and light particles that revolve around...
the electrons.
In turn, the core is constituted by smaller 
particles: the positively charged protons...
and the neutrons without electric charge.
They are constituted by
even smaller particles: quarks.
In addition to these fundamental particles,
many more have been discovered.
They are now divided into leptons,
which include electrons and neutrinos...
and quarks, which exist in six different forms.
Up and down, making up protons and neutrons...
The Charm, the Strange, the Top, the Bottom.
In addition to these, we must consider the particles
who act as mediators for the fundamental forces.
In other words, particles that are exchanged by
leptons and quarks when they interact with each other.
Most of these particles have
a very short average life.
Indeed, the current universe is constituted by
the lighter particles, i.e. electrons...
neutrinos, and the up and down quarks.
To produce heavy particles is necessary
to provide a large amount of energy.
If we could go back in time, to
the origins of our universe...
we would find that the energy was enough to allow
the stable existence of all the known particles.
At CERN laboratories, this energy is supplied
by interacting beams of particles...
which are accelerated at very high speed.
The energy released in the collision is
likely to produce new, incredible particles.
But how it performs in real life an high
energy physics experiment?
We are entering an experimental area for CERN
to find out what really happens in these huge sheds...
true sanctuaries of modern science.
Prof. Domenico Elia from INFN agreed
to guide us in this amazing journey.
CERN has made possible some of the most important
scientific discoveries of the last decades.
But how does work the CERN? And what are these
incredibly sophisticated machines...
making it a unique in the scientific world?
Particle accelerators, in fact.
Let's see together then, some of the corridors...
for experts, in this mysterious laboratory.
Come with me.
We are in the immediate vicinity
of the true experimental area.
Beyond these concrete blocks that
you see behind me...
it takes place the experiment.
Targets of different materials are invested
by the particles produced by the accelerator.
In the interaction, i.e. the clash
between bullet and target...
take places the production of numerous particles
called "secondary".
The presence of these particles in
the experimental area is clearly a danger...
for the health of those working in these areas.
For this reason, at the sides of this corridor...
there are blocks of concrete that
constitute a screen...
from this radiation.
Another danger we face in the
experimental areas...
is the presence of intense magnetic fields,
necessary for the realization of many measures...
properly marked by the presence
of luminous signs...
like the one you see behind me.
We will now go beyond this door...
to find out...
the experiment area, passing
through a further door...
this time with controlled access.
This is one of the access controlled doors
for zones with the presence of beam particles.
It is the door 134 of the North Area at CERN.
Beyond this door we will closely see...
the measuring apparatus of one of the
most evocative CERN's experiments...
the experiment NA57.
An experiment where...
the particles of the incident beam, are...
lead nuclei.
NA57 is the name of the experiment where
Prof. Elia is working.
It take place in the North of CERN,
within this huge shed.
The particles are conveyed through a
vacuum tube on a thin sheet of lead...
within this huge magnet.
The magnet is necessary to study
the properties of the particles produced...
which are detected by special equipments.
To avoid the electronic equipment overheating...
you must use special refrigerants.
The tubes you see provide cold air
in close proximity to them.
The realization of an experiment at CERN...
requires months of preparation...
and many hours of hard work.
But the work in direct contact
with particle detectors...
constitutes only a small part of the total.
The result of the collision of
the fast lead ion incident...
on the lead target...
at CERN energies is the production of a large
number of particles called "secondary".
This is the information that the
particle detectors will store...
for each individual interaction event...
allowing the subsequent analysis.
The enormous amount of data to be recorded
in a very short time...
and the complexity of the
particle detectors itself...
impose a continuous supervision.
This control is what we call
"Monitoring on-line".
And that's what we accomplish in the
experiment "Counting Room".
Let's have a close look.
Come with me.
We go from the work on the experimental area...
to a terminal for the detector calibration.
We continue to prepare detectors for data taking...
determining thresholds, noisy channels, etc...
for their finalization.
The NA57 Counting Room...
is pervaded by a flurry of activity.
Dozens of monitors allow you to control even
the smallest details of the experiment.
For instance, this monitor shows instant by instant
the state of the particle beam incident on the target.
A series of dedicated computers
allows to intervene on many elements...
as voltages, the calibration of the
detectors and even the magnetic fields.
Some of these controls, however, must be made
directly on the modules of the electronic devices...
located in a separate room.
Dr. Rocco Caliandro from University of Bari...
is examining the signals coming
directly from the detectors.
As you can see, the trigger of the experiment...
is the set of electronics required to
the revelation of the produced particles.
You can see the number of cables,
the complexity of the equipment.
We need very fast signals to
reveal high energy particles.
Dr. Caliandro explains how the signals allow
to count the number of the produced particles.
These numbers appear directly on a TV screen.
The informations are then sent to computers
for later analysis.
The analysis of data occupies
the last part of the work.
It requires the cooperation of numerous experts,
developing programs extremely complex...
which also require months of execution time.
Experiments as NA57 may require
several years of preparation...
and many more years of data
acquisition and analysis.
But what is the purpose of all this?
What are in fact these experiments?
To learn more about NA57, we meet here at CERN...
one of the leaders of the experiment...
Prof. Haavard Helstrup,
University of Bergen, Norway.
What are you looking for in NA57 experiment?
We want to study the very early phases of the Universe.
We know that today the world is made
of protons and neutrons...
Which are made of quarks.
However we think that at the beginning of the universe,
the quarks were "melted" in the "Quark-Gluon Plasma"...
In NA57 we are trying to reproduce
this phase of the matter.
Usually, in particle physics the
projectiles are made of light particles.
Why are you in your experiment using
lead ions as projectiles?
In order to create this big system with many
quarks and gluons...
we need the highest energy density available.
We can have this result from a
lead-lead collision at CERN energies.
May be this will not be enough, so we are
thinking at even powerfull accelerators.
How do you Know that such condition
have been realized in the collisions?
Of course we do not really know...
But we know that if such plasma is created...
then we expect an high production of
a new type of quark (the strange).
So, the produced particles will be made of
a large number of strange quarks.
The preliminary results indicate that the amount of
strange quarks produced in this collisions are
about 10 times larger than in normal collisions.
This could indicate that this conditions could have been
realized in this collisions.
On 10 February 2000, at a press
conference at CERN...
it was officially announced the discovery of a new
state of matter produced in lead-lead collisions.
The temperature at which the new state is formed, is
100000 times greater than that in the center of sun.
In order to achieve this fantastic value ions of lead
must be accelerated closely to the speed of light.
This is the purpose of the CERN accelerators,
the largest so far built by man.
Accelerators are sophisticated machines...
the purpose of which is to bring
elementary particles...
electrically charged...
at very high speeds, approaching that of light.
CERN has the largest, and by far
one of the machines...
most complex ever built by man.
The electron-positron collider called LEP.
(Now LHC)
The acceleration of particles is in fact
a complex and delicate procedure...
which can be realized only through
subsequent stages...
by using accelerating machines
with gradually increasing power.
This is what happens here at CERN...
where the particles are accelerated
in advance by linear accelerators...
and then injected into a first
circular accelerator...
the Proton Synchrotron...
that you see here.
Then they are injected into a larger
accelerator, about 9 km in circumference...
the Super Proton Synchrotron.
Finally they have enough energy to be inserted...
in the cycle of large accelerator LEP.
It is a ring of almost 30 km in circumference...
positioned approximately 100 m
below the earth's surface.
And it is here that ends the long journey
of the particles through the accelerator.
The work of the high energy physicist
is often held in very poor conditions.
It requires considerable sacrifice
and a complete dedication.
But how CERN researchers spend their time
outside of their work?
The high energy physicist is basically a "big kid".
The entertainment options are scarce...
and each gets by as he can.
The problem of the meals is solved by a
canteen service working all the week.
Physicists, and in particular Italians
however, are always looking for alternatives.
After a day of work, I think
physicists deserve a decent dinner.
A dinner gropu at one of the many
apartments for rent near CERN...
constitutes an irresistible attraction.
