A first look on the matter of the Big Bang

The major LHC experiments related to CERN in Geneva - the Large Hadron Collider - warm up the muscles, and they do it by giants, winning one result after another. The latest announcement came as part of the researchers involved in the CMS experiment, one of four built to study the results of the impact between the particles that collide in the large underground ring. If confirmed, the result could take us back in time to the very first instants of the Universe, when there were no nuclei of atoms.
CMS is a colossus of 14 thousand tons, distributed in an object with a diameter of 15 meters and length of 29. To build it took 16 years and the efforts of one of the largest scientific collaborations ever created: working there 3100 scientists from 169 research institutions in 39 countries, and among them there are many Italian researchers, starting with the spokesperson Guido Tonelli, who explained: "We can only keep to the facts and it is something that we have never seen before." Like other related experiments at the LHC, CMS also has been built to answer questions of a very long process on the origins and nature of the Universe and, in particular, is dedicated to investigate the clashes between protons accelerated to high energy.
In these bumps protons generate a cascade of other particles, the number of which is very variable: in general it is a twenty, but can also be many tens. Focusing on the impact that the final result is 100 or more particles, the researchers observed that in these cases some of them tend to be distributed in groups, show that they are in some way related. A correlation of this kind had already been observed in the past in experiments carried out at the laboratories of Brookhaven, in the United States, where, however, were not to collide protons but nuclei of gold atoms and, therefore, objects with mass much greater.
"The fact that the same effect observed in collisions between gold nuclei is also found in clashes between protons in itself is interesting and lends itself to many different interpretations," says Sergio Bertolucci, director of research at CERN. For example it could be a phenomenon due to the nature of quarks, elementary particles that make up protons and all the atomic nuclei. But there are also explanations bolder, despite the physical express the greatest caution.
One of them even throw a glance at the first moments after the Big Bang.
At that time, according to some theories, have existed for a very short time what physicists call a plasma of quarks and gluons. Today quark do not exist in the free state, but only joined together to form more complex particles. To make the glue is the so-called "strong force," a fundamental force that can be described as the effect of an ongoing exchange between quarks of other particles called gluons precisely. In the mists of time is the quarks and gluons would enjoy a short-lived freedom and for a fraction of a second would behave like a drop of liquid exploding, expanding at incredible speed.
An imperceptible amount of time later, the quarks would find themselves shackled by gluons: a condition that made possible the formation of atomic nuclei and, in the course of billions of years, even in the matter that makes up our bodies. "From the experimental point of view the existence of the quark-gluon plasma just after the Big Bang has never been fully tested. The results of the experiment at Brookhaven, however, according to some interpretations would give indications in this sense and, if so, the announcement of CMS would be an additional test, "says Antonello Polosa, a theoretical physicist at the University of Rome La Sapienza.
It is still too early to tell if the result of CMS open a window really unusual about the origins of the cosmos. But it is only a matter of time to have new clues. Another of the great experiments connected with the LHC, "Alice", was in fact designed precisely to study the plasma of quarks and gluons, and before long we will know what it has to say about that. And in the meantime, CMS will continue to investigate, as well as the experiment "Atlas" which of the four LHC is connected to its nearest competitor.