Physicists at the University of Zurich have discovered using the Large Hadron Collider (LHC), a previously unknown particle composed of three quarks. They found a new baryon, known as Xi_b ^ *. This discovery confirms the fundamental physical assumptions about the interaction of baryons.
In particle physics, the baryons - a particle composed of three quarks. In total there are six types of quarks, which differ from each other in mass and charge. Two of the light quarks, the so-called "top" and "bottom" quarks, form the two components of the atom: protons and neutrons. At the moment, aware of all the baryons composed of three lightest quarks ("lower", "upper" and "strange" quarks). But so far been found only a few baryons composed of heavy quarks. They can be created artificially in particle accelerators as they are heavy and very unstable.
By colliding protons in the LHC (CERN), physicists Claude Emsler, Vincenzo Chiochia and Ernest Agvilo from the Institute of Physics in Zurich found a baryon with one light and two heavy quarks. Particle Xi_b ^ *, is composed of one of the "upper" one "strange" and a "delightful" quark (WWW). It is electrically neutral and has a spin of 3/2 (1.5). By weight it is comparable to the lithium atom. Thus was opened the second of three baryons composition GSP that predicted by the theory.
This new particle can not be detected directly, because it is too unstable for the sensors. But as a set of products is known for its collapse, it is the presence of these products has issued a new particle. Ernest Agvilo identified traces of the products of decay and was able to reconstruct the decay cascade, starting with the collapse of Xi_b ^ *.
These calculations are based on data from proton-proton collisions with a total energy of 7 TeV (TeV) collected by the CMS detector between April and November 2011. In total, there were 21 recorded baryon decay Xi_b ^ * - that’s enough to reject the possibility of statistical error.
This discovery of a new particle confirms the theory of the interaction of quarks and a deeper understanding the strong interaction, one of the four basic forces of physics that determine the structure of matter.