5,769 research outputs found
ATLAS RPC offline monitoring and data quality assessment
In this work several aspects of ATLAS RPC offline monitoring and data quality
assessment are illustrated with cosmics data selected by RPC trigger. These
correspond to trigger selection, front-end mapping, detection efficiency and
occupancy, which are studied in terms of low level quantities such as: RPC
off-line hits and standalone tracks. The tools and techniques presented are
also extended to the forthcoming LHC p-p beam collisions.Comment: Poster section at ICHEP08, Philadelphia, USA, July 2008. 3 pages,
LaTeX, 3 eps figure
KLOE results at the Frascati -factory DANE
The KLOE experiment at the Frascati -factory DANE has collected
about 0.5 fb of data till the end of the year 2002. These data allow to
perform a wide physics program, ranging from the physics of charged and neutral
kaons to radiative -decays. Results are presented for the lifetime
and the semileptonic processes . From the light meson
spectroscopy program, results on the decays as well as are presented.Comment: 5 pages, 3 figures, Proceedings contribution to the 10th Int.
Symposium on "Meson-Nucleon Physics and the Structure of the Nucleon"
(MENU04), Beijing, China, Aug. 30 - Sept. 4, 200
Cosmology of fermionic dark matter
We explore a model for a fermionic dark matter particle family which
decouples from the rest of the partices when at least all standard model
particles are in equilibrium. We calculate the allowed ranges for mass and
chemical potential to be compatible with big bang nucleosynthesis (BBN)
calculations and WMAP-data for a flat universe with dark energy. Futhermore we
estimate the free streaming length for fermions and antifermions to allow
comparison to large scale structure data (LLS). We find that for dark matter
decoupling when all standard model particles are present even the least
restrictive combined BBN calculation and WMAP results allow us to constrain the
initial dark matter chemical potential to a highest value of 6.3 times the dark
matter temperature. In this case the resulting mass range is at most 1.8 eV < m
< 53 eV, where the upper bound scales linearly with the effective degrees of
freedom at decoupling. From LSS we find that similar to ordinary warm dark
matter models the particle mass has to be larger than approximately 500 eV
(meaning the effective degrees of freedom at decoupling have to be > 1000) to
be compatible with observations of the Ly alpha forest at high redshift, but
still the dark matter chemical potential over temperature ratio can exceed
unity.Comment: 14 pages, 13 figures; Submitted to Phys. Rev. Lett. D., minor changes
after referee report: references added, several minor extensions (mostly to
the introduction). Also conclusion extended with an additional summary plot
to clarify the result
Inverse Spin Hall Effect and Anomalous Hall Effect in a Two-Dimensional Electron Gas
We study the coupled dynamics of spin and charge currents in a
two-dimensional electron gas in the transport diffusive regime. For systems
with inversion symmetry there are established relations between the spin Hall
effect, the anomalous Hall effect and the inverse spin Hall effect. However, in
two-dimensional electron gases of semiconductors like GaAs, inversion symmetry
is broken so that the standard arguments do not apply. We demonstrate that in
the presence of a Rashba type of spin-orbit coupling (broken structural
inversion symmetry) the anomalous Hall effect, the spin Hall and inverse spin
Hall effect are substantially different effects. Furthermore we discuss the
inverse spin Hall effect for a two-dimensional electron gas with Rashba and
Dresselhaus spin-orbit coupling; our results agree with a recent experiment.Comment: 5 page
Reply to Comment on: Hawking radiation from ultrashort laser pulse filaments
A comment by R. Schutzhold et al. raises possible concerns and questions
regarding recent measurements of analogue Hawking radiation. We briefly reply
to the opinions expressed in the comment and sustain that the origin of the
radiation may be understood in terms of Hawking emission
Quantum theory as a relevant framework for the statement of probabilistic and many-valued logic
Based on ideas of quantum theory of open systems we propose the consistent
approach to the formulation of logic of plausible propositions. To this end we
associate with every plausible proposition diagonal matrix of its likelihood
and examine it as density matrix of relevant quantum system. We are showing
that all logical connectives between plausible propositions can be represented
as special positive valued transformations of these matrices. We demonstrate
also the above transformations can be realized in relevant composite quantum
systems by quantum engineering methods. The approach proposed allows one not
only to reproduce and generalize results of well-known logical systems
(Boolean, Lukasiewicz and so on) but also to classify and analyze from unified
point of view various actual problems in psychophysics and social sciences.Comment: 7 page
Depressive and anxiety symptoms screening in cardiac inpatients : a virtuous italian approach to psychocardiology
Despite the fact that American Heart Association (AHA) recommended a systematic screening for depression in cardiovascular inpatients, poor attention has been given to this issue. Furthermore, no specific guidelines exist for anxiety screening in cardiovascular inpatients. Thus, the aims of this study were to verify the feasibility of a depressive and anxiety symptoms screening protocol in an Italian hospital specializing in cardiovascular diseases and to evaluate both anxiety and depressive symptoms prevalence. A group of 2009 consecutive inpatients completed the 9-item Patient Health Questionnaire (PHQ-9) and the 7-item Generalized Anxiety Disorder (GAD-7). The rates of depressive and anxiety symptoms were almost 9% and 16% respectively. Men were less likely than women to experience both depressive and anxiety symptoms. Patients who were admitted to the heart failure unit reported higher risk of experiencing both symptoms compared to patients in other wards. Similarly, patients admitted to the cardiac surgery unit showed a higher risk of experiencing anxiety symptoms compared to other patients. The proposed screening procedure showed a good feasibility and acceptance. This study highlighted the importance of implementing a short screening procedure in hospitals dealing with cardiovascular inpatients to identify those individuals who require specific attention and interventions
Scalar models for the generalized Chaplygin gas and the structure formation constraints
The generalized Chaplygin gas model represents an attempt to unify dark
matter and dark energy. It is characterized by a fluid with an equation of
state . It can be obtained from a generalization of the
DBI action for a scalar, tachyonic field. At background level, this model gives
very good results, but it suffers from many drawbacks at perturbative level. We
show that, while for background analysis it is possible to consider any value
for , the perturbative analysis must be restricted to positive values
of . This restriction can be circumvented if the origin of the
generalized Chaplygin gas is traced back to a self-interacting scalar field,
instead of the DBI action. But, in doing so, the predictions coming from
formation of large scale structures reduce the generalized Chaplygin gas model
to a kind of quintessence model, and the unification scenario is lost, if the
scalar field is the canonical one. However, if the unification condition is
imposed from the beginning as a prior, the model may remain competitive. More
interesting results, concerning the unification program, are obtained if a
non-canonical self-interacting scalar field, inspired by Rastall's theory of
gravity, is imposed. In this case, an agreement with the background tests is
possible.Comment: Latex file, 25 pages, 33 figures in eps format. New section on scalar
models. Accepted for publication in Gravitation&Cosmolog
ATLAS RPC Quality Assurance results at INFN Lecce
The main results of the quality assurance tests performed on the Resistive
Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are
reported and discussed.
Since July 2004, about 270 RPC units has been certified at INFN Lecce site
and delivered to CERN, for being integrated in the final muon station of the
ATLAS barrel region.
We show the key RPC characteristics which qualify the performance of this
detector technology as muon trigger chamber in the harsh LHC enviroments.
These are dark current, chamber efficiency, noise rate, gas volume
tomography, and gas leakage.Comment: Comments: 6 pages, 1 table, 9 figures Proceedings of XXV Physics in
Collision-Prague, Czech Republic, 6-9 July 200
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