5 research outputs found
System size and centrality dependence of the balance function in A+A collisions at sqrt[sNN]=17.2 GeV
Electric charge correlations were studied for p+p, C+C, Si+Si, and centrality selected Pb+Pb collisions at sqrt[sNN]=17.2 GeV with the NA49 large acceptance detector at the CERN SPS. In particular, long-range pseudorapidity correlations of oppositely charged particles were measured using the balance function method. The width of the balance function decreases with increasing system size and centrality of the reactions. This decrease could be related to an increasing delay of hadronization in central Pb+Pb collisions
Overview of Results from NA61/SHINE: Uncovering Critical Structures
NA61/SHINE is a multi-purpose experiment to study hadron–proton, hadron–nucleus and nucleus–nucleus collisions at the CERN Super Proton Synchrotron. The experiment performs unique measurements for physics of strong interactions as well as important reference measurements for neutrino and cosmic-ray physics. The results from the strong interaction programme uncover rapid changes in collision-energy and system-size dependence of basic hadron production properties—the critical structures. They are attributed to the onset of deconfinement, onset of fireball and may indicate the critical point of strongly interacting matter
Shell beds from the Low Head Member (Polonez Cove Formation, early Oligocene) at King George Island, west Antarctica: new insights on facies analysis, taphonomy and environmental significance
Shell bed levels in the Low Head Member of the early Oligocene Polonez Cove Formation at King George Island, West Antarctica, are re-interpreted based on sedimentological and taphonomic data. The highly fossiliferous Polonez Cove Formation is characterized by basal coastal marine sandstones, overlain by conglomerates and breccias deposited in fan-delta systems. The shell beds are mainly composed of pectinid bivalve shells of Leoclunipecten gazdzickii and occur in the basal portion of the Low Head Member. Three main episodes of bioclastic deposition are recorded. Although these shell beds were previously interpreted as shelly tempestites, we present an alternative explanation: the low fragmentation rates and low size sorting of the bioclasts resulted from winnowing due to tidal currents (background or diurnal condition) in the original bivalve habitat. The final deposition (episodic condition) was associated with subaqueous gravity driven flows. This new interpretation fits with the scenario of a prograding fan-delta front, which transported shell accumulations for short distances near the depositional site, possibly between fair-weather and storm wave bases. This work raises the notion that not every shell bed with similar sedimentological and taphonomic features (such as geometry, basal contact, degree of packing and shell orientation in the matrix) is made in the same way.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq