Net-lambda fluctuations in Pb-Pb collisions at √S_NN = 5.02 TeV in ALICE at the LHC

The analysis describes the measurement of the first and second cumulants of net-Λ distribution in Pb-Pb collisions at √S_NN = 5.02 TeV using the ALICE detector. A fundamental goal of heavy-ion collision experiment is to map out the temperature (T_f) and baryon chemical potential (µ_B^f) parameters of the Quantum chromodynamics (QCD) phase diagram at which chemical freeze-out occurs – a point on the phase diagram when particle species produced are fixed. The cumulants of conserved quantities (net-charge, net-baryon, net-strangeness) are directly related to the quark number susceptibilities calculated with lattice QCD. In a fluctuation analysis, net-pion, net-proton, and net-kaon are typically used as proxies for net-charge, net-baryon, and net-strangeness respectively. The lambda particle consists of a strange quark and it is as well a baryon. Hence, measuring the cumulants of net-Λ provides insight into the fluctuations of net-strangeness and net-baryon number. In addition, the ratios of the net-Λ cumulants used to extract T_f and μ_B^f can be compared to those of net-proton to identify the signature of a flavor hierarchy, that is, if heavier quarks freeze-out at a different T_f and μ_B^f from lighter quarks.