The global geometrical property of jet events in high-energy nuclear collisions

We present the first theoretical study of medium modifications of the global geometrical pattern, i.e., transverse sphericity ($$S_{\perp }$$ S ⊥ ) distribution of jet events with parton energy loss in relativistic heavy-ion collisions. In our investigation, POWHEG + PYTHIA is employed to make an accurate description of transverse sphericity in the p + p baseline, which combines the next-to-leading order (NLO) pQCD calculations with the matched parton shower (PS). The Linear Boltzmann Transport (LBT) model of the parton energy loss is implemented to simulate the in-medium evolution of jets. We calculate the event normalized transverse sphericity distribution in central Pb + Pb collisions at the LHC, and give its medium modifications. An enhancement of transverse sphericity distribution at small $$S_{\perp }$$ S ⊥ region but a suppression at large $$S_{\perp }$$ S ⊥ region are observed in A + A collisions as compared to their p + p references, which indicates that in overall the geometry of jet events in Pb + Pb becomes more pencil-like. We demonstrate that for events with 2 jets in the final-state of heavy-ion collisions, the jet quenching makes the geometry more sphere-like with medium-induced gluon radiation. However, for events with $$\ge 3$$ ≥ 3 jets, parton energy loss in the QCD medium leads to the events more pencil-like due to jet number reduction, where less energetic jets may lose their energies and then fall off the jet selection kinematic cut. These two effects offset each other and in the end result in more jetty events in heavy-ion collisions relative to that in p + p.

Review of Spirulina/Arthrospira Growth Medium Modifications

Nutrients and their content in growth medium significantly affect the growth rate and quality of biomass. This review summaries the latest studies on microalgae Arthrospira spp. and Spirulina spp. growth media. Most of studied growth media are modified Zarrouk’s medium. Detailly discussed are effects of change in some microelement concentration and sources and salinity or NaCl concentration, however there are still lacking studies on microelement role and long-term studies. It should be highlighted that various species and strains of Arthrospira and Spirulina reacts to growth media composition change very differently. There is no single best growth media formulae for all species and strains of Arthrospira/Spirulina. Recycling for few times is possible but content of biomass changes.

Particle Production in Heavy Ion Collisions at Intermediate Energies

We investigate the influence of the in-medium modifications of nucleon-nucleon cross sections on the particle production in heavy ion collisions at intermediate energies. In particular, it is shown that the pion and kaon yields and their rapidity distributions are strongly affected by the density dependence of the inelastic cross sections. On the other hand, the particle ratios depend less on the in-medium behavior of the inelastic cross sections.

Effects of the in-medium NN cross sections in heavy ion collisions on particle production

The density dependence of the in-medium nucleon-nucleon (NN) cross sections is investigated in terms of particle production in heavy ion collisions (HIC). It is found, in particular, that the in-medium modifications of the inelastic NN cross sections considerably affect the pion yields and improve the comparison with experimental information. Such studies are important in determining the still unknown behavior of the nuclear equation of state (EoS) at supra-normal densities in HIC.

Event Plane Dependence of Jet-Hadron Correlations in Au–Au Collisions at √sNN = 200 GeV with the STAR Detector at RHIC

The phenomenon of jet quenching indicates that partons lose energy as they traverse the hot dense medium. By restricting a trigger jet in azimuth relative to the event plane, we are given another tool, which allows us to study the path length dependence of medium modifications. Measurements of angular correlations relative to the event plane between reconstructed R = 0 . 4 full jets and charged hadrons are presented in mid-peripheral Au–Au collisions at s N N = 200 GeV with the STAR detector at RHIC. A robust and precise method, known as the Reaction Plane Fit (RPF) method is used to remove the complex, flow-dominated heavy-ion background from the correlation functions. Quantified through yield ratios, we study the event plane dependence of jet-correlated yields. The yield ratios are compared to prior measurements made by the ALICE Collaboration in Pb–Pb collisions at s N N = 2 . 76 TeV. With increased statistics and smaller uncertainties, the results from STAR show a similar conclusion to that of ALICE, that within uncertainties this measurement shows no significant path length dependence of medium modifications.