2,161 research outputs found
Formation of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC and their Identification by the ALICE Experiment
We present a phenomenological model which describes the formation of a
Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and
at the LHC, and its decay to non-strange baryons and Strangelets. We describe
the CASTOR detector for the ALICE experiment at the LHC. CASTOR will probe, in
an event-by-event mode, the very forward, baryon-rich phase space 5.6 < \eta <
7.2 in 5.5 A TeV central Pb + Pb collisions. We present results of simulations
for the response of the CASTOR calorimeter, and in particular to the traversal
of Strangelets.Comment: 4 pages, 4 figures, to appear in the proceedings of the 26th ICR
RPC with low-resistive phosphate glass electrodes as a candidate for the CBM TOF
Usage of electrodes made of glass with low bulk resistivity seems to be a
promising way to adapt the Resistive Plate Chambers (RPC) to the high-rate
environment of the upcoming CBM experiment. A pilot four-gap RPC sample with
electrodes made of phosphate glass, which has bulk resistivity in the order of
10^10 Ohm cm, has been studied with MIP beam for TOF applications. The tests
have yielded satisfactory results: the efficiency remains above 95% and the
time resolution stays within 120 ps up to the particle rate of 18 kHz/cm2. The
increase in rate from 2.25 to 18 kHz/cm2 leads to an increase of estimated
"tails" fraction in the time spectrum from 1.5% to 4%.Comment: 8 pages, 6 figures, submitted to Elsevier Scienc
Changes in the Structural and Functional Albumin Properties in Patients with Decompensated Liver Cirrhosis
Аim: to conduct a comparative analysis of serum albumin's structural and functional properties in decompensated cirrhotic patients by means of spin prob EPR spectroscopy.Materials and methods. The main study group included 70 patients with decompensated liver cirrhosis and ascites. The control group consisted of 12 healthy volunteers, comparable in gender and age, without liver diseases. To assess the structural and functional ability, serum albumin was analyzed by EPR spectroscopy.Results. Albumin levels within reference intervals were found in 37 patients (59.8 %). The native albumin index decrease in cirrhotic patients as the disease progressed with the lowest values in the Child – Pugh C group (p < 0.001). The binding efficiency of albumin decreased in accordance with the severity of cirrhosis with minimal albumin binding capacity in the Child – Pugh C (Me = 25.43 %; n = 30; p < 0.001). The transport activity of RTQ albumin decreased in patients with decompensated cirrhosis, the lowest transport ability was observed in the Child – Pugh C group (Me = 26.09 %). In patients with decompensated disease the detoxification potential was significantly reduced: Child – Pugh B — Me = 44.03 %; Child – Pugh C — Me =17.16 %. Despite the normal values of serum albumin in 72.5% of patients with cirrhosis B and in 26.7% in the cirrhosis C group, only 12.3% in the cirrhosis B group had normal albumin function and in cirrhosis C nо patients had normal albumin function.Conclusion. There were not only serum concentration depletion in cirrhotic patients, but also albumin physiological non-oncotic properties were violated. The severity of these changes increased with the progression of cirrhosis. Our data allow us to raise the question of the need to use the EPR test to determine indications for albumin replacement therapy in patients with cirrhosis and the presence of ascites, even at normal values of its serum concentration
The Role of Correcting Structural and Functional Albumin Properties in Ascites Control in Decompensated Cirrhotic Patients
Аim: to study the structural and functional characteristics of albumin in patients with decompensated cirrhosis, their relationship with ascites; to identify the relationship between improvement in albumin characteristics and regression of ascites.Materials and methods. Fifty patients with decompensated liver cirrhosis and ascites were divided into groups. The first group received standard treatment for cirrhosis, the second — standard treatment and replacement therapy with 20 % human albumin solution at a dose of 200 mL per week for 3 months.Results. The value of the native conformation of albumin and the functional parameters of albumin were significantly lower than in the group of healthy individuals (p < 0.001). With the severity of ascites, the native conformation index (DR), which characterizes the structural usefulness of the albumin molecule, decreased. Median DR for ascites stage I (IAC) was –1.69, II grade — –2.28, III grade — –2.42 (p < 0.05). Replacement therapy with albumin allowed to achieve regression of ascites in 48.4 % of patients, compared with 7.1 % in the standard treatment group. Along with clinical improvement, restoration of albumin structural and functional properties was observed in the albumin group. The mean serum albumin level at which ascites remained in remission for 3 months was 42.11 g/L (p < 0.001).Conclusions and discussion. The structural and functional characteristics of albumin were impaired in patients with decompensated cirrhosis and ascites. The severity of changes in the structural and functional properties of albumin depended on the severity of ascites. The regression of ascites was accompanied by the restoration of the functional and structural usefulness of albumin against the backdrop of albumin replacement therapy. The criterion for stopping transfusion therapy with albumin can be the achievement of a serum albumin level of 42.11 ± 7.04 g/L, DR — 1.05, BE — 73.51 %, RTQ — 75.10 %, DTE — 72.71 %
CASTOR: A Forward Detector for the Identification of Centauro and Strangelets in Nucleus-Nucleus Collisions at the LHC
Presentation made at the XXVIIIth Symposium on Multiparticle Dynamics, 6-11 September 1998, Delphi and published in World ScientificThe physics motivation for a very forward detector to be employed in heavy ion collisions at the CERN LHC is discussed. A phenomenological model describing the formation and decay of a Centauro fireball in nucleus-nucleus collisions is presented. The CASTOR detector which is aimed to measure the hadronic and photonic content of an interaction and to identify deeply penetrating objects in the very forward, baryon-rich phase space 5.6eta7.2 in an event-by-event mode is described. Results of simulations of the expected response of the calorimeter and, in particular, to the passage of strangelets, are presented
Formation of Centauro in Pb+Pb Collisions at the LHC and their Identification in the ALICE Experiment
Presentation made at EPS-HEP'99 and submitted to IOP PublishingWe present a phenomenological model which describes the formation of a Centauro fireball in nucleus-nucleus interactions in the upper atmosphere and at the LHC, and its decay to non-strange baryons and strangeness-rich objects. We describe the CASTOR calorimeter for the ALICE experiment at the LHC. CASTOR will probe the very forward, baryon-rich phase space 5.6eta7.2 in 5.5xA TeV central Pb+Pb collisions. We present results of simulations for the response of CASTOR to the passage of strangeness-rich objects
Charge separation relative to the reaction plane in Pb-Pb collisions at TeV
Measurements of charge dependent azimuthal correlations with the ALICE
detector at the LHC are reported for Pb-Pb collisions at TeV. Two- and three-particle charge-dependent azimuthal correlations in
the pseudo-rapidity range are presented as a function of the
collision centrality, particle separation in pseudo-rapidity, and transverse
momentum. A clear signal compatible with a charge-dependent separation relative
to the reaction plane is observed, which shows little or no collision energy
dependence when compared to measurements at RHIC energies. This provides a new
insight for understanding the nature of the charge dependent azimuthal
correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published
version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at = 5.02 TeV
Two-particle angular correlations between unidentified charged trigger and
associated particles are measured by the ALICE detector in p-Pb collisions at a
nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum
range 0.7 5.0 GeV/ is examined,
to include correlations induced by jets originating from low
momen\-tum-transfer scatterings (minijets). The correlations expressed as
associated yield per trigger particle are obtained in the pseudorapidity range
. The near-side long-range pseudorapidity correlations observed in
high-multiplicity p-Pb collisions are subtracted from both near-side
short-range and away-side correlations in order to remove the non-jet-like
components. The yields in the jet-like peaks are found to be invariant with
event multiplicity with the exception of events with low multiplicity. This
invariance is consistent with the particles being produced via the incoherent
fragmentation of multiple parton--parton scatterings, while the yield related
to the previously observed ridge structures is not jet-related. The number of
uncorrelated sources of particle production is found to increase linearly with
multiplicity, suggesting no saturation of the number of multi-parton
interactions even in the highest multiplicity p-Pb collisions. Further, the
number scales in the intermediate multiplicity region with the number of binary
nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/161
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