1,104 research outputs found
Constituent Quark Scaling of Strangeness Enhancement in Heavy-Ion Collisions
In the frame work of a nuclear overlap model, we estimate the number of
nucleon and quark participants in proton-proton, proton-nucleus and
nucleus-nucleus collisions. We observe the number of nucleon
()-normalized enhancement of multi-strange particles which show a
monotonic increase with centrality, turns out to be a centrality independent
scaling behavior when normalized to number of constituent quarks participating
in the collision (). In addition, we observe that the
-normalized enhancement, when further normalized to the strangeness
content, shows a strangeness independent scaling behavior. This holds good at
top RHIC energy. However, the corresponding SPS data show a weak
-scaling with strangeness scaling being violated at top SPS energy.
This scaling at RHIC indicates that the partonic degrees of freedom playing an
important role in the production of multi-strange particles. Top SPS energy, in
view of the above observations, shows a co-existence of hadronic and partonic
phases. We give a comparison of data with HIJING, AMPT and UrQMD models to
understand the particle production dynamics at different energies.Comment: 9 pages, 17 figure
Charged Particle and Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions
We review the charged particle and photon multiplicity, and transverse energy
production in heavy-ion collisions starting from few GeV to TeV energies. The
experimental results of pseudorapidity distribution of charged particles and
photons at different collision energies and centralities are discussed. We also
discuss the hypothesis of limiting fragmentation and expansion dynamics using
the Landau hydrodynamics and the underlying physics. Meanwhile, we present the
estimation of initial energy density multiplied with formation time as a
function of different collision energies and centralities. In the end, the
transverse energy per charged particle in connection with the chemical
freeze-out criteria is discussed. We invoke various models and phenomenological
arguments to interpret and characterize the fireball created in heavy-ion
collisions. This review overall provides a scope to understand the heavy-ion
collision data and a possible formation of a deconfined phase of partons via
the global observables like charged particles, photons and the transverse
energy measurement.Comment: 27 pages, 43 figures, Invited Review for Advances in High Energy
physics for Special Issue on "Global properties in High Energy Collisions
Effective-energy budget in multiparticle production in nuclear collisions
The dependencies of charged particle pseudorapidity density and transverse
energy pseudorapidity density at midrapidity on the collision energy and on the
number of nucleon participants, or centrality, measured in nucleus-nucleus
collisions are studied in the energy range spanning a few GeV to a few TeV per
nucleon. The model in which the multiparticle production is driven by the
dissipating effective energy of participants is introduced. The model is based
on the earlier proposed approach, combining the constituent quark picture
together with Landau relativistic hydrodynamics shown to interrelate the
measurements from different types of collisions. Within this model, the
dependence on the number of participants in heavy-ion collisions are found to
be well described in terms of the effective energy defined as a
centrality-dependent fraction of the collision energy. For both variables under
study, the effective energy approach reveals a similarity in the energy
dependence obtained for the most central collisions and centrality data in the
entire available energy range. Predictions are made for the investigated
dependencies for the forthcoming higher energy measurements in heavy-ion
collisions at the LHC.Comment: Regular article, Replaced with published versio
Biochemical Changes during Gonadal Maturation Portunus pelagicus (Linnaeus, 1758)
The changes in moisture, protein, lipid, carbohydrate and carotenoids in the ovary, hepatopancreas, muscle and haemolymph during the process of gonadal maturation of the
crab PorhmllS pelagiclls (Linnaeus, 1758) were nvestigated. There was significant difference (p<O.Ol) in moisture, protein and carotenoid levels at various maturity stages. The lipid content showed significant difference (p<O.Ol) in all the tissues except in muscle tissue and the
carbohydrate values showed significant difference (p<O.01) only for ovary and hepatopancreas. The moisture content decreased with gonadal maturation in all the tissues. The protein titre increased with maturity in ovary, muscle and haemolymph whereas in hepatopancreas it registered a decrease. The lipid values of all the tissues and the haemolymph showed an v increasing trend with maturation. The carbohydrate level also increased with gonadal maturity
in the tissues and haemolymph. The carotenoid content followed an increasing trend till mature stage in the ovary whereas in the hepatopancreas and haemolymph it increased till the late maturing stage
Energy and Centrality dependence of and in Heavy-Ion Collisions from =7.7 GeV to 5.02 TeV
The centrality dependence of pseudorapidity density of charged particles and
transverse energy is studied for a wide range of collision energies for
heavy-ion collisions at midrapidity from 7.7 GeV to 5.02 TeV. A two-component
model approach has been adopted to quantify the soft and hard components of
particle production, coming from nucleon participants and binary
nucleon-nucleon collisions, respectively. Within experimental uncertainties,
the hard component contributing to the particle production has been found not
to show any clear collision energy dependence from RHIC to LHC. The effect of
centrality and collision energy in particle production seem to factor out with
some degree of dependency on the collision species. The collision of
Uranium-like deformed nuclei opens up new challenges in understanding the
energy-centrality factorization, which is evident from the centrality
dependence of transverse energy density, when compared to collision of
symmetric nuclei.Comment: Published version in Eur. Phys. J.
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