PageContent

With its twenty meters in length, thirteen in width and ten in height, the LHCb detector aims at investigating some mysteries of the Universe and answering, for example, the following question. Why had matter and antimatter existed in equal quantity at the origin of the Universe a few moments after the Big Bang and has completely disappeared today? The LHCb experiment is searching for an answer studying the tiny differences between matter and antimatter through the decay of elementary particles containing the quarks beauty and charm, formed into proton collisions and very high energies at LHC.

The link between a particle and its corresponding antiparticle is named “CP” symmetry (combined action of charge reversal and spatial reflection). If the particle and the corresponding antiparticle behave in the same way concerning the laws of physics, then the CP symmetry is said to be conserved, otherwise, it’s violated. The LHCb experiment measures CP symmetries in different decays modes. An observation of a substantial effect would explain the reason for the absence of antimatter in the Universe.

Questa immagine ha l'attributo alt vuoto; il nome del file è image.pngInternal view of the LHCb experiment. The long pipe in the foreground is a section of the beam that crosses the LHCb detector. Inside, protons circulate in both directions with speeds close to those of light. The LHCb magnet is positioned around the beam pipe, capable of producing a magnetic field of maximum intensity of approximately one Tesla.

To date, several experimental measurements have measured CP violation, including those carried out by the LHCb experiment and researchers from the Bologna group.  However, the amount of asymmetry observed is not sufficient to explain the absence of antimatter in our galaxies. These results have only one implication. The Universe should be made up not only of known particles but also of a class of new particles and antiparticles, named Dark Matter, that behave differently than the laws of nature, violating the CP symmetry much more than ordinary particles. Several astronomical observations have indirectly found that Dark Matter and Dark Energy constitute 95% of the whole Universe. LHCb aims at demonstrating the existence of this new class of elementary particles not foreseen by the Standard Model.

Questa immagine ha l'attributo alt vuoto; il nome del file è lhcb_collaboration.jpgThe LHCb collaboration is made up of around 850 representatives from 80 universities and laboratories around the world.

The LHCb-Bologna group has been participating in the LHCb collaboration for over twenty years. About 15 members, including researchers, technologists, research fellows, PhD students, undergraduate and graduate students, are daily working together with the same objective, i.e. pushing forward the knowledge of particle physics. The group has a leading role in analyzing the data recorded by the LHCb experiment, with the primary objective of measuring CP violation and searching for the existence of new particles. In the last decade, the LHCb-Bologna group have contributed to obtaining results of central importance for the High Energy Physics community such as the discovery of CP violation in B0s-meson, and D0-meson decays. Both results had a significant scientific impact, and they have been chosen as the editor’s suggestion by the Physics Review Letter and as one of the ten finalists for the Physics World 2019 Breakthrough award by the magazine Physics World.
In addition to data analysis, the LHCb-Bologna group collaborates to Data Acquisition System (DAQ) and commissioning of the calorimeter of the LHCb-upgrade detector. The R&D interests of the group are focused on the designing and developing of a new concept of a calorimeter and a vertex detector with timing information for the LHCb-Upgrade-II experiment, that in case of approval, will run during the High-Luminosity phase of LHC.

Bologna-INFN group leader

Angelo Carbone           email:  angelo.carbone@bo.infn.it

LHCb web site