TSU scientist: CERN found traces of a long-sought quasiparticle

9 February 2018

In December 2017, scientists at the TOTEM experiment at the Large Hadron Collider demonstrated measurements that indicate the existence of an odderon. This is a quasiparticle that physicists have been searching for since the 1970s. The only participant in this experiment from Russia is Tomsk State University.

CERN scientists are studying the processes that arise when protons collide, dispersed with the help of the Large Hadron Collider to colossal energies. In central collisions, a special state of matter - the quark-gluon plasma - can form, and in peripheral collisions bound states can form - objects called quasiparticles, which are not particles but behave similarly.

The hypothesis of the existence of an odderon expressed by theorists in the 1970s refers to the bound state of an odd number of gluons. In atomic nuclei, gluons keep protons and neutrons together and also “glue” quarks in the protons and neutrons themselves.

Until now, during the experiments with the interaction of protons, the formation of quasiparticles consisting of only an even number of gluons has been observed. The latest measurements demonstrated for the first time the evidence of an exchange of an odd number of gluons.

- For the first time in history, TOTEM measured energy at 13 TeV, the largest beam energy ever achieved , - said Yevgeny Chernyaev, a member of the TSU Laboratory of Experimental High Energy Physics. - The data obtained cannot be explained by any of the currently existing theoretical models of hadron elastic interaction, because they assume that this interaction is related to the exchange of two or more even numbers of coupled gluons. Even if the existence of the odderon is not confirmed, in any case, the results of TOTEM are an opening that completes the coin box of our knowledge about the behavior of elementary particles and gives a new idea of the Standard Model of elementary particle physics.

Preprints CERN-EP-2017-321 and CERN-EP-2017-335 with the latest results of TOTEM measurements are available on the CERN server. Publications in physics journals are now being prepared.

The TOTEM experiment is organized by an international group of scientists - about 100 physicists from 20 scientific institutes of 8 countries. Vladimir Ivanchenko and Yevgeny Chernyaev, the leading scientific employees of the Laboratory of Experimental Physics of High Energies of TSU, represent us in TOTEM.

TOTEM has the longest experimental setup at the Large Hadron Collider; its detectors are located at a distance of about half a kilometer. The specificity of the experiment is the measurement of proton scattering at very small angles. Since the scattering angles are extremely small, the detectors must be brought close to the beam, at a distance of about one millimeter.