1,302 research outputs found
System-size dependence of the pion freeze-out volume as a potential signature for the phase transition to a Quark Gluon Plasma
Hanburry-Brown-Twiss (HBT) correlation functions and radii of negatively
charged pions from C+C, Si+Si, Cu+Cu, and In+In at lower RHIC/SPS energies are
calculated with the UrQMD transport model and the CRAB analyzing program. We
find a minimum in the excitation function of the pion freeze-out volume at low
transverse momenta and around GeV which can be related to
the transition from hadronic to string matter (which might be interpreted as a
pre-cursor of the QGP). The existence of the minimum is explained by the
competition of two mechanisms of the particle production, resonance decays and
string formation/fragmentation.Comment: 12 pages, 4 fig
Early (and Later) LHC Search Strategies for Broad Dimuon Resonances
Resonance searches generally focus on narrow states that would produce a
sharp peak rising over background. Early LHC running will, however, be
sensitive primarily to broad resonances. In this paper we demonstrate that
statistical methods should suffice to find broad resonances and distinguish
them from both background and contact interactions over a large range of
previously unexplored parameter space. We furthermore introduce an angular
measure we call ellipticity, which measures how forward (or backward) the muon
is in eta, and allows for discrimination between models with different parity
violation early in the LHC running. We contrast this with existing angular
observables and demonstrate that ellipticity is superior for discrimination
based on parity violation, while others are better at spin determination.Comment: 31 pages, 19 figures. References added, minor modifications made to
section
A statistical interpretation of the correlation between intermediate mass fragment multiplicity and transverse energy
Multifragment emission following Xe+Au collisions at 30, 40, 50 and 60 AMeV
has been studied with multidetector systems covering nearly 4-pi in solid
angle. The correlations of both the intermediate mass fragment and light
charged particle multiplicities with the transverse energy are explored. A
comparison is made with results from a similar system, Xe+Bi at 28 AMeV. The
experimental trends are compared to statistical model predictions.Comment: 7 pages, submitted to Phys. Rev.
The energy dependence of flow in Ni induced collisions from 400 to 1970A MeV
We study the energy dependence of collective (hydrodynamic-like) nuclear
matter flow in 400-1970 A MeV Ni+Au and 1000-1970 A MeV Ni+Cu reactions. The
flow increases with energy, reaches a maximum, and then gradually decreases at
higher energies. A way of comparing the energy dependence of flow values for
different projectile-target mass combinations is introduced, which demonstrates
a common scaling behaviour among flow values from different systems.Comment: 12 pages, 3 figures. Submitted to Physical Review Letter
Statistical signatures of critical behavior in small systems
The cluster distributions of different systems are examined to search for
signatures of a continuous phase transition. In a system known to possess such
a phase transition, both sensitive and insensitive signatures are present;
while in systems known not to possess such a phase transition, only insensitive
signatures are present. It is shown that nuclear multifragmentation results in
cluster distributions belonging to the former category, suggesting that the
fragments are the result of a continuous phase transition.Comment: 31 pages, two columns with 30 figure
Liquid-gas phase transition in nuclear multifragmentation
The equation of state of nuclear matter suggests that at suitable beam
energies the disassembling hot system formed in heavy ion collisions will pass
through a liquid-gas coexistence region. Searching for the signatures of the
phase transition has been a very important focal point of experimental
endeavours in heavy ion collisions, in the last fifteen years. Simultaneously
theoretical models have been developed to provide information about the
equation of state and reaction mechanisms consistent with the experimental
observables. This article is a review of this endeavour.Comment: 63 pages, 27 figures, submitted to Adv. Nucl. Phys. Some typos
corrected, minor text change
Radial Flow in Au+Au Collisions at E=0.25-1.15 A GeV
A systematic study of energy spectra for light particles emitted at
midrapidity from Au+Au collisions at E=0.25-1.15 A GeV reveals a significant
non-thermal component consistent with a collective radial flow. This component
is evaluated as a function of bombarding energy and event centrality.
Comparisons to Quantum Molecular Dynamics (QMD) and Boltzmann-Uehling-Uhlenbeck
(BUU) models are made for different equations of state.Comment: 10 pages of text and 4 figures (all ps files in a uuencoded package)
Circumstantial Evidence for a Critical Behavior in Peripheral Au + Au Collisions at 35 MeV/nucleon
The fragmentation resulting from peripheral Au + Au collisions at an incident
energy of E = 35 MeV/nucleon is investigated. A power-law charge distribution,
with , and an intermittency signal are observed
for events selected in the region of the Campi scatter plot where "critical"
behavior is expected.Comment: 11 pages, RevTex file, 4 postscript figures available upon request
from [email protected]
Functional properties of measles virus proteins derived from a subacute sclerosing panencephalitis patient who received repeated remdesivir treatments
Subacute sclerosing panencephalitis (SSPE) is a rare but fatal late neurological complication of measles, caused by persistent measles virus (MeV) infection of the central nervous system. There are no drugs approved for the treatment of SSPE. Here, we followed the clinical progression of a 5-year-old SSPE patient after treatment with the nucleoside analog remdesivir, conducted a post-mortem evaluation of the patientâs brain, and characterized the MeV detected in the brain. The quality of life of the patient transiently improved after the first two courses of remdesivir, but a third course had no further clinical effect, and the patient eventually succumbed to his condition. Post-mortem evaluation of the brain displayed histopathological changes including loss of neurons and demyelination paired with abundant presence of MeV RNA-positive cells throughout the brain. Next-generation sequencing of RNA isolated from the brain revealed a complete MeV genome with mutations that are typically detected in SSPE, characterized by a hypermutated M gene. Additional mutations were detected in the polymerase (L) gene, which were not associated with resistance to remdesivir. Functional characterization showed that mutations in the F gene led to a hyperfusogenic phenotype predominantly mediated by N465I. Additionally, recombinant wild-type-based MeV with the SSPE-F gene or the F gene with the N465I mutation was no longer lymphotropic but instead efficiently disseminated in neural cultures. Altogether, this case encourages further investigation of remdesivir as a potential treatment of SSPE and highlights the necessity to functionally understand SSPE-causing MeV.</p
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