296 research outputs found

    Strangeness Enhancement in p+p, p+Pb and Pb+Pb Collisions at LHC Energies

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    We investigate whether the quark gluon plasma (QGP) is created in small colliding systems from analyses of various hadron yields and their ratios in proton-proton (p+p), proton-lead (p+Pb) and lead-lead (Pb+Pb) collisions at LHC energies. Recently, the ALICE Collaboration reports enhancement of yield ratio of multi-strange hadrons to charged pions as a function of multiplicity at mid-rapidity. Motivated by these results, we develop the dynamical core-corona initialization framework and find that our results describe tendencies of the ALICE data especially for multi-strange hadrons. These results indicate that the QGP is partly formed in high multiplicity events in small colliding systems.Comment: 4 pages, 5 figures; contribution to the proceedings of the 8th International Conference on Quarks and Nuclear Physics (QNP2018), Tsukuba, November 13-17, 201

    Nonlinear two-dimensional terahertz photon echo and rotational spectroscopy in the gas phase

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    Ultrafast two-dimensional spectroscopy utilizes correlated multiple light-matter interactions for retrieving dynamic features that may otherwise be hidden under the linear spectrum. Its extension to the terahertz regime of the electromagnetic spectrum, where a rich variety of material degrees of freedom reside, remains an experimental challenge. Here we report ultrafast two-dimensional terahertz spectroscopy of gas-phase molecular rotors at room temperature. Using time-delayed terahertz pulse pairs, we observe photon echoes and other nonlinear signals resulting from molecular dipole orientation induced by three terahertz field-dipole interactions. The nonlinear time-domain orientation signals are mapped into the frequency domain in two-dimensional rotational spectra which reveal J-state-resolved nonlinear rotational dynamics. The approach enables direct observation of correlated rotational transitions and may reveal rotational coupling and relaxation pathways in the ground electronic and vibrational state.Comment: 31 pages, 14 figure

    Incidence of Blood and Meat Spots in Eggs from a Commercial Poultry Farm

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    A study was conducted in two phases simultaneously in a commercial poultry farm to ascertain whether egg weight, temperature variation in pens, and proximity of birds to a noise source had an influence on the incidence of blood and meat spots in chicken eggs. Phase one involved the random sampling of 60 eggs per week for 15 weeks, making a total of 900 eggs from the pens of a 50-week-old layer strain. Phase two determined the effect of noise from a 3.3 kW electrical gasoline generator on the incidence of blood and meat spots. It lasted for 14 weeks and involved the random sampling of 10 eggs per week directly from two pens (i.e., A & D). Pen A and D were 4.7 m and 68 m away from the noise source respectively. A Chi-square test was conducted to establish the relationship between the parameters, whilst a Cramer’s V test was used to determine the extent of association where differences were deemed significant (p<0.05). Out of the 1040 eggs collected, 63% of the eggs had spots (32% blood spots and 31% meat spots). No association was observed between the occurrence of spots and egg weight, temperature variation, and proximity of birds to a generator
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