Speaker
Description
We discuss measurements of event-by-event relative hadron yield fluctuations with the νdyn observable in Pb — Pb collisions at sNN = 2.76 TeV. Fluctuation measurements presented include the relative yield of charged hadrons, the relative yield of identified pions (π) vs. kaons (K), π vs. protons (p) , K vs. p, as well as the more recent measurements of fluctuations of K+ vs. K− yields and charged kaons (K±) vs. neutral kaons (K0s) yields. Measured values of νdyn as well as values of νdyn scaled by the produced particle multiplicity are reported as a function of Pb — Pb collision centrality. Measured and scaled data are compared to predictions from various models, including the HIJING and AMPT models. It is found that while most relative yield fluctuations considered exhibit an approximate scaling with inverse multiplicity, which is qualitatively reproduced by HIJING and AMPT, the relative yields of π vs. p and K± vs. K0s fluctuations show strong departure from simple scaling behavior. The former exhibits a change of sign from peripheral to central collisions whereas the latter exhibits strongly enhanced scaled values in central collisions. The K± vs. K0s anomalous behavior is discussed in light of recent theoretical considerations, including the possibility of strange Disoriented Chiral Condensates (DCC) and Disoriented Isospin Condensate (DIC).
