305 research outputs found
Electrical and mechanical properties of Bi-2223/Ag tapes made by TIRT technique
Multi-core Bi-2223/Ag tapes with various number of filaments (21â162), different filament architecture and their changing orientation to the tape plane have been made by the tape-in-rectangular tube (TIRT) process. The transport current properties of TIRT tape samples with âparallelâ and âperpendicularâ filaments have been measured. The transversal Ic distribution obtained by spatially resolved transport measurements (âmagnetic knifeâ) measurement illustrates that filament quality of TIRT tapes is better at the tape edges as in its centre. The Ic degradation due to bending shows a different behaviour for parallel and perpendicular filaments which is attributed to the difference in filament density and crack propagation
Search for weakly interacting sub-eV particles with the OSQAR laser-based experiment: results and perspectives
Recent theoretical and experimental studies highlight the possibility of new
fundamental particle physics beyond the Standard Model that can be probed by
sub-eV energy experiments. The OSQAR photon regeneration experiment looks for
"Light Shining through a Wall" (LSW) from the quantum oscillation of optical
photons into "Weakly Interacting Sub-eV Particles" (WISPs), like axion or
axion-like particles (ALPs), in a 9 T transverse magnetic field over the
unprecedented length of m. No excess of events has been
detected over the background. The di-photon couplings of possible new light
scalar and pseudo-scalar particles can be constrained in the massless limit to
be less than GeV. These results are very close to the
most stringent laboratory constraints obtained for the coupling of ALPs to two
photons. Plans for further improving the sensitivity of the OSQAR experiment
are presented.Comment: 7 pages, 7 figure
MesonNet 2013 International Workshop. Mini-proceedings
The mini-proceedings of the MesonNet 2013 International Workshop held in
Prague from June 17th to 19th, 2013, are presented. MesonNet is a research
network within EU HadronPhysics3 project (1/2012 -- 12/2014). The web page of
the conference, which contains all talks, can be found at
http://ipnp.mff.cuni.cz/mesonnet13Comment: 106 pages, 53 contributions. Mini-proceedings of the MesonNet 2013
International Workshop. Editors: K. Kampf, A. Kupsc, and P. Masjua
Latest Results of the OSQAR Photon Regeneration Experiment for Axion-Like Particle Search
The OSQAR photon regeneration experiment searches for pseudoscalar and scalar
axion-like particles by the method of "Light Shining Through a Wall", based on
the assumption that these weakly interacting sub-eV particles couple to two
photons to give rise to quantum oscillations with optical photons in strong
magnetic field. No excess of events has been observed, which constrains the
di-photon coupling strength of both pseudoscalar and scalar particles down to
GeV in the massless limit. This result is the most
stringent constraint on the di-photon coupling strength ever achieved in
laboratory experiments.Comment: 6 pages, 5 figures. appears in Proceedings of the 10th PATRAS
Workshop on Axions, WIMPs and WISPs (2014
MesonNet 2014 International Workshop. Mini-proceedings
The MesonNet International Workshop was held in the Laboratori Nazionali di Frascati from September the 29th to October the 1st, 2014, being the concluding meeting of the MesonNet research network within EU HadronPhysics3 project. MesonNet is a research network focused on light meson physics gathering experimentalist and theoreticians from Europe and abroad. An overview of the research projects related to the scope of the network is presented in these mini-proceedings
Disaturated-phosphatidylcholine and Surfactant protein-B turnover in human acute lung injury and in control patients
<p>Abstract</p> <p>Background</p> <p>Patients with Adult Respiratory Distress Syndrome (ARDS) and Acute Lung Injury (ALI) have low concentrations of disaturated-phosphatidylcholine and surfactant protein-B in bronchoalveolar lavage fluid. No information is available on their turnover.</p> <p>Objectives</p> <p>To analyze disaturated-phosphatidylcholine and surfactant protein-B turnover in patients with ARDS/ALI and in human adults with normal lungs (controls).</p> <p>Methods</p> <p><sup>2</sup>H<sub>2</sub>O as precursor of disaturated-phosphatidylcholine-palmitate and 1<sup>13</sup>C-Leucine as precursor of surfactant protein-B were administered intravenously to 12 patients with ARDS/ALI and to 8 controls. Disaturated-phosphatidylcholine and surfactant protein-B were isolated from serial tracheal aspirates, and their fractional synthetic rate was derived from the <sup>2</sup>H and <sup>13</sup>C enrichment curves, obtained by gas chromatography mass spectrometry. Disaturated-phosphatidylcholine, surfactant protein-B, and protein concentrations in tracheal aspirates were also measured.</p> <p>Results</p> <p>1) Surfactant protein-B turned over at faster rate than disaturated-phosphatidylcholine both in ARDS/ALI patients and in controls. 2) In patients with ARDS/ALI the fractional synthesis rate of disaturated-phosphatidylcholine was 3.1 times higher than in controls (p < 0.01), while the fractional synthesis rate of surfactant protein-B was not different. 3) In ARDS/ALI patients the concentrations of disaturated-phosphatidylcholine and surfactant protein-B in tracheal aspirates were markedly and significantly reduced (17% and 40% of the control values respectively).</p> <p>Conclusions</p> <p>1) Disaturated-phosphatidylcholine and surfactant protein-B have a different turnover both in healthy and diseased lungs. 2) In ARDS/ALI the synthesis of these two surfactant components may be differently regulated.</p
MesonNet 2014 International Workshop. Mini-proceedings
The MesonNet International Workshop was held in the Laboratori Nazionali di
Frascati from September the 29th to October the 1st, 2014, being the concluding
meeting of the MesonNet research network within EU HadronPhysics3 project.
MesonNet is a research network focused on light meson physics gathering
experimentalist and theoreticians from Europe and abroad. An overview of the
research projects related to the scope of the network is presented in these
mini-proceedings.Comment: 93 pages, 12 figures, MesonNet 2014 International Workshop, 29/9 -
1/10 Frascati LNF INF
Workshop summary -- Kaons@CERN 2023
Kaon physics is at a turning point -- while the rare-kaon experiments NA62
and KOTO are in full swing, the end of their lifetime is approaching and the
future experimental landscape needs to be defined. With HIKE, KOTO-II and
LHCb-Phase-II on the table and under scrutiny, it is a very good moment in time
to take stock and contemplate about the opportunities these experiments and
theoretical developments provide for particle physics in the coming decade and
beyond. This paper provides a compact summary of talks and discussions from the
Kaons@CERN 2023 workshop.Comment: 54 pages, Summary of Kaons@CERN 23 workshop, references and
clarifications adde
Performance of the NA62 trigger system
The NA62 experiment at CERN targets the measurement of the ultra-rare
K+ ->pi+ nu nu decay, and carries out a broad physics programme that includes probes for
symmetry violations and searches for exotic particles. Data were collected in 2016â2018
using a multi-level trigger system, which is described highlighting performance studies
based on 2018 data
Search for Ïâ° decays to invisible particles
The NA62 experiment at the CERN SPS reports a study of a sample of 4 Ă 109 tagged Ï0 mesons from K+ â Ï+Ï0(Îł), searching for the decay of the Ï0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 Ă 10â9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be interpreted as a model- independent upper limit on the branching ratio for the decay K+ â Ï+X, where X is a particle escaping detection with mass in the range 0.110â0.155 GeV/c2 and rest lifetime greater than 100 ps. Model-dependent upper limits are obtained assuming X to be an axion-like particle with dominant fermion couplings or a dark scalar mixing with the Standard Model Higgs boson
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