Speaker
Description
We report the first measurement of the Ξ(1820) baryon at LHC energies by reconstructing its decay to Λ-Κ in pp collisions at 13 TeV. Recent lattice calculations on parity doubling indicate that the masses of negative-parity particles, such as Ξ(1820), may decrease at the critical temperature, while the masses of positive-parity partners, i.e. the Ξ(1530), do not. Furthermore, the lifetime of the Ξ(1820) is short enough that it may be suppressed in high-multiplicity collisions, as has been observed for K*(892) and ρ(770). Studying Ξ(1820) also allows us to gain a better understanding of the spectrum of excited hyperon states, with implications for our understanding of the hadron resonance gas. We have successfully reconstructed the Ξ(1820) using ALICE data from 2015-2018 and measured its mass, width, and yield as a function of the transverse momentum and collision multiplicity. These studies performed in small collision systems will serve as a baseline for future measurements of the Ξ(1820) in p-Pb and Pb-Pb collisions.
