In the middle of the 20th century, scientists began to understand that elementary particles - proton and neutron are not so simple. They not only consist of more miniature "bricks", but constant complex interactions of fundamental particles still occur within them. Thus, according to the results of studies of the proton structure in the 1960s, it turned out that it consists of three components, which later called quarks.
The initial model meant that in the proton - three quarts: two upper and one lower. Relative height epithets are used by metaphorically physicists, they only help to make the terms easier and slightly clearer. This simplified model (it is so now called - "naive") with three quarks in Proton helped to explain many effects observed during experiments. But not all.
Later it was possible to establish that the presence of only three quarks did not describe the proton structure. If briefly, a series of experiments in deeply inelastic collisions of these particles showed that everything is more complicated. In the proton there are three "main" quark (two top and one lower), as well as many couples quark antiquarian, which constantly occur and annihile. That is, in fact, a positive nucleon is "soup" from underracticly interacting fundamental particles.
But in this case, the problem arose: why in every single moment of time three quarks inside the proton there is no pair in the form of antiquark? This contradicts many theoretical calculations and looks extremely unnatural in terms of physics. Actually, the above question is the essence of the fundamental asymmetry of the proton.
And even without his permission, it was still necessary to clarify the structure of a positive nucleon, which was engaged in the late 1990s of the Nosea collaboration (E866) on the basis of the National Acceleration Laboratory of Enrico Fermi (Fermilab) in the United States. Physics faced overclocked protons overclocked to high energies and recorded traces of such events. Then it was possible to confirm the asymmetry of the distribution of quarks in protons for a relatively narrow range by quarks of the pulses of the "maternal" particle. And on the basis of this data, a distant one was made and let the rather believable, but still not confirmed by practically a forecast: in other ranges, the proton pulse, asymmetry, who worn by quarks, will disappear.
A bold statement pretty shook the scientific community, but looked quite reasonably. So a number of previously worked models had to throw and make the creation of new ones. Fortunately, the essence of the scientific method of knowledge is in constant verification of the results. Therefore, quite recently, a new experiment on the capacities is all the same Fermilab. And he seriously corrected the colleagues received more than 20 years ago.
The results of this experience are the publication in the peer-reviewed journal Nature, which a large international team of physicists has prepared. It was attended by specialists from the leading American, Taiwanese, Israeli and Japanese technological research institutes, as well as the largest physical laboratories of the United States and Japan. The main data array was collected at the FermilaB accelerator within the E-906 / Seaquest experiment.
When two protons collide with sufficiently high energies, quarks in them interact with each other. Or rather, the quark of one proton annihilates with an anti-coast of another or vice versa. Simply put, "soups" are mixed. The product of such annihilation will be virtual (that is, it cannot be detected directly) photon or Z-boson, which will almost immediately break into a couple of oppositely charged muons. It is by catching these particles with detectors, scientists judge the characteristics of interacting quarks.
For the experiment, a bunch of protons with an energy of 120 gigaelectronvolt (not a record, but a lot), aimed at the target of liquid hydrogen and deuterium (they consist mainly from protons). To fix only muons and filter any other particle colliding products, between the target and detectors placed a five-meter iron wall. The results were impressive: the asymmetry described somewhat above was preserved for quarks, carrying out 10% more pulse of the entire subatomic particle.
Of course, this is not a loud revolution in physics, but serious experimental confirmation of a number of theories and an application for the adjustment of others. One way or another, scientists even further expanded the understanding of the proton structure. And this will further bring its fruits in various fields of science and technology: from cosmology with astronomy and physics to chemistry, medicine and materials science.
Source: Naked Science