Matter-antimatter trigonometry with LHCb

The unitarity triangle is shown above, with each experimental input represented by a coloured region. Click for a detailed description of the graph (Image: LHCb)

Today at Les Rencontres de Physique de la Vallée d'Aoste, La Thuile, Italy, the LHCb collaboration presented an important result in the quest to understand the nature and origin of CP violation, which is a difference in behaviour between matter and antimatter. The result, derived from a careful analysis of the full Run 1 data sample, is a measurement of the angle β of the ‘unitarity triangle’. This triangle is a geometrical representation of CP violating and associated parameters in the Standard Model. One side is defined to have unit length, the other two sides and three angles can be measured independently in different decays of beauty hadrons. Experiments can measure these properties to see if they provide a consistent description of the triangle. Any discrepancy would point to signs of new physics beyond the Standard Model. LHCb has already performed the world’s most precise measurements of γ, one of the other triangle angles, see 11 September 2014 news, and the mixing frequency of Bs mesons, see 7 November 2012 news, which is an essential ingredient for the determination of the side opposite to the angle γ.

Read more: "Matter-antimatter trigonometry with LHCb" – LHCb public page