301 research outputs found
p_T-fluctuations in high-energy p-p and A-A collisions
The event-by-event p_T-fluctuations in proton-proton and central Pb-Pb
collisions, which have been experimentally studied by means of the so-called
Phi-measure, are analyzed. The contribution due to the correlation which
couples the average p_T to the event multiplicity is computed. The correlation
appears to be far too weak to explain the preliminary experimental value of Phi
(p_T) in p-p interactions. The significance of the result is discussed.Comment: 5 pages, 2 figures, minor improvement
Comparison of openEHR and HL7 FHIR standards
Health informatics is characterized by the need tosecurely store, process and transmit large amounts of sensitivemedical data while ensuring interoperability with other systems.Among many standards used in such systems there are two whichhave gained interest in recent years and cover most of thoseneeds: openEHR and HL7 FHIR. In this paper, both standardsare discussed and compared with each other. The architecture ofboth systems, the similarities and differences, methods of datamodeling and ensuring interoperability were presented
Strangeness and Quark Gluon Plasma
A brief summary of strangeness mile stones is followed by a chemical
non-equilibrium statistical hadronization analysis of strangeness results at
SPS and RHIC. Strange particle production in AA interactions at
\sqrt{s_{NN}}\ge 8.6 GeV can be understood consistently as originating from the
deconfined quark--gluon plasma in a sudden hadronization process. Onset of QGP
formation as function of energy is placed in the beam energy interval 10--30A
GeV/c. Strangeness anomalies at LHC are described.Comment: 30 pages including numerouse figures, tables. Opening Lecture:
Strangeness and Quark Gluon Plasma -- what has been learned so far and where
do we go at SQM2003, North Carolina, March 2003, submitted to J. Phys.
Baryon Stopping and Charged Particle Distributions in Central Pb+Pb Collisions at 158 GeV per Nucleon
Net proton and negative hadron spectra for central \PbPb collisions at 158
GeV per nucleon at the CERN SPS were measured and compared to spectra from
lighter systems. Net baryon distributions were derived from those of net
protons, utilizing model calculations of isospin contributions as well as data
and model calculations of strange baryon distributions. Stopping (rapidity
shift with respect to the beam) and mean transverse momentum \meanpt of net
baryons increase with system size. The rapidity density of negative hadrons
scales with the number of participant nucleons for nuclear collisions, whereas
their \meanpt is independent of system size. The \meanpt dependence upon
particle mass and system size is consistent with larger transverse flow
velocity at midrapidity for \PbPb compared to \SS central collisions.Comment: This version accepted for publication in PRL. 4 pages, 3 figures.
Typos corrected, some paragraphs expanded in response to referee comments, to
better explain details of analysi
Measurement of the diffractive structure function in deep inelastic scattering at HERA
This paper presents an analysis of the inclusive properties of diffractive
deep inelastic scattering events produced in interactions at HERA. The
events are characterised by a rapidity gap between the outgoing proton system
and the remaining hadronic system. Inclusive distributions are presented and
compared with Monte Carlo models for diffractive processes. The data are
consistent with models where the pomeron structure function has a hard and a
soft contribution. The diffractive structure function is measured as a function
of \xpom, the momentum fraction lost by the proton, of , the momentum
fraction of the struck quark with respect to \xpom, and of . The \xpom
dependence is consistent with the form \xpoma where
in all bins of and
. In the measured range, the diffractive structure function
approximately scales with at fixed . In an Ingelman-Schlein type
model, where commonly used pomeron flux factor normalisations are assumed, it
is found that the quarks within the pomeron do not saturate the momentum sum
rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil
D* Production in Deep Inelastic Scattering at HERA
This paper presents measurements of D^{*\pm} production in deep inelastic
scattering from collisions between 27.5 GeV positrons and 820 GeV protons. The
data have been taken with the ZEUS detector at HERA. The decay channel
(+ c.c.) has been used in the study. The
cross section for inclusive D^{*\pm} production with
and is 5.3 \pms 1.0 \pms 0.8 nb in the kinematic region
{ GeV and }. Differential cross
sections as functions of p_T(D^{*\pm}), and are
compared with next-to-leading order QCD calculations based on the photon-gluon
fusion production mechanism. After an extrapolation of the cross section to the
full kinematic region in p_T(D^{*\pm}) and (D^{*\pm}), the charm
contribution to the proton structure function is
determined for Bjorken between 2 10 and 5 10.Comment: 17 pages including 4 figure
Observation of hard scattering in photoproduction events with a large rapidity gap at HERA
Events with a large rapidity gap and total transverse energy greater than 5
GeV have been observed in quasi-real photoproduction at HERA with the ZEUS
detector. The distribution of these events as a function of the
centre of mass energy is consistent with diffractive scattering. For total
transverse energies above 12 GeV, the hadronic final states show predominantly
a two-jet structure with each jet having a transverse energy greater than 4
GeV. For the two-jet events, little energy flow is found outside the jets. This
observation is consistent with the hard scattering of a quasi-real photon with
a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil
Observation of Scaling Violations in Scaled Momentum Distributions at HERA
Charged particle production has been measured in deep inelastic scattering
(DIS) events over a large range of and using the ZEUS detector. The
evolution of the scaled momentum, , with in the range 10 to 1280
, has been investigated in the current fragmentation region of the Breit
frame. The results show clear evidence, in a single experiment, for scaling
violations in scaled momenta as a function of .Comment: 21 pages including 4 figures, to be published in Physics Letters B.
Two references adde
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