551 research outputs found
Hadron yields in Au+Au/Pb+Pb at RHIC and LHC from thermalized minijets
We calculate the yields of a variety of hadrons for RHIC and LHC energies
assuming thermodynamical equilibration of the produced minijets, and using as
input results from pQCD for the energy densities at midrapidity. In the
calculation of the production of partons and of transverse energy one has to
account for nuclear shadowing. By using two parametrizations for the gluon
shadowing one derives energy densities differing strongly in magnitude. In this
publication we link those perturbatively calculated energy densities of partons
via entropy conservation in an ideal fluid to the hadron multiplicities at
chemical freeze-out.Comment: 11 pages, 2 .eps figure
Non-equilibrium initial conditions from pQCD for RHIC and LHC
We calculate the initial non-equilibrium conditions from perturbative QCD
(pQCD) within Glauber multiple scattering theory for AGeV and
ATeV. At the soon available collider energies one will
particularly test the small region of the parton distributions entering the
cross sections. Therefore shadowing effects, previously more or less
unimportant, will lead to new effects on variables such as particle
multiplicities , transverse energy production , and the
initial temperature . In this paper we will have a closer look on the
effects of shadowing by employing different parametrizations for the shadowing
effect for valence quarks, sea quarks and gluons. Since the cross sections at
midrapidity are dominated by processes involving gluons the amount of their
depletion is particularly important. We will therefore have a closer look on
the results for , , and by using two different
gluon shadowing ratios, differing strongly in size. As a matter of fact, the
calculated quantities differ significantly.Comment: typo in ref's removed, ack's added, no change in result
Charmonium suppression from purely geometrical effects
The extend to which geometrical effects contribute to the production and
suppression of the and minijet pairs in general is
investigated for high energy heavy ion collisions at SPS, RHIC and LHC
energies. For the energy range under investigation, the geometrical effects
referred to are shadowing and anti-shadowing, respectively. Due to those
effects, the parton distributions in nuclei deviate from the naive
extrapolation from the free nucleon result; . The strength
of the shadowing/anti-shadowing effect increases with the mass number. The
consequences of gluonic shadowing effects for the distribution of
's at GeV, GeV and TeV are
calculated for some relevant combinations of nuclei, as well as the
distribution of minijets at midrapidity for in the final state.Comment: corrected some typos, improved shadowing ratio
Prompt photons at RHIC
We calculate the inclusive cross section for prompt photon production in
heavy-ion collisions at RHIC energies ( GeV and
GeV) in the central rapidity region including next-to-leading order,
, radiative corrections, initial state nuclear
shadowing and parton energy loss effects. We show that there is a significant
suppression of the nuclear cross section, up to at
GeV, due to shadowing and medium induced parton energy loss effects. We find
that the next-to-leading order contributions are large and have a strong
dependence.Comment: 9 pages, 5 figures, expanded discussion of the K facto
Two-hadron interference fragmentation functions. Part I: general framework
We investigate the properties of interference fragmentation functions
measurable from the distribution of two hadrons produced in the same jet in the
current fragmentation region of a hard process. We discuss the azimuthal
angular dependences in the leading order cross section of two-hadron inclusive
lepton-nucleon scattering as an example how these interference fragmentation
functions can be addressed separately.Comment: RevTeX, 7 figures, first part of a work split in two, second part
forthcoming in few day
Hard Parton Rescatterings and Minijets in Nuclear Collisions at LHC
The average number of minijets and the corresponding transverse energy
produced in heavy ion collisions are evaluated by including explicitly
semi-hard parton rescatterings in the dynamics of the interaction. At the LHC
semi-hard rescatterings have a sizable effect on global characteristics of the
typical inelastic event. An interesting feature is that the dependence on the
cutoff which separates soft and hard parton interactions becomes less critical
after taking rescatterings into account.Comment: 14 pages, 3 figures. Enlarged discussion in sect.1 and 4; 1 figure
added. To be published in Phys.Rev.
Identifying and accommodating education/research barriers of rural nursing staff in the Mississippi River Delta
Session presented on Sunday, September 18, 2016:
The purpose of this study was to identify by survey, what education and research barriers exist for operating room and post anesthesia care nursing staff in the rural hospitals of the Mississippi River Delta
Bounds on transverse momentum dependent distribution and fragmentation functions
We give bounds on the distribution and fragmentation functions that appear at
leading order in deep inelastic 1-particle inclusive leptoproduction or in
Drell-Yan processes. These bounds simply follow from positivity of the defining
matrix elements and are an important guidance in estimating the magnitude of
the azimuthal and spin asymmetries in these processes.Comment: 5 pages, Revtex, 3 Postscript figures, version with minor changes, to
be published in Physical Review Letter
Covenants as Quasi Contracts
It is the scope of this article to discuss briefly certain forms of covenant with a view to determining whether in their nature they are contractual or quasi contractual. Quasi contract may be defined as an obligation whereby one person becomes bound to another, without regard to his consent, by a legal tie similar to that arising from contract. It may exist either by statute or by common law, and, if by the latter, it may be enforced either on principle or by reason of custom. As to the cause of the obligation, it may be imposed upon a man because he occupies a peculiar relation, public or private, or because of his acts or omissions. And since agreement or the semblance of one is not an element of the obligation, it may arise where the person bound was unconscious or undesirous of assuming any liability whatever,-or where he was desirous of assuming a different liability from that imposed
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