| 1. |
- Schael, S, et al.
(författare)
-
Precision electroweak measurements on the Z resonance
- 2006
-
Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
-
Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
|
|
| 2. |
- Aamodt, K., et al.
(författare)
-
The ALICE experiment at the CERN LHC
- 2008
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
-
Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
|
|
| 3. |
|
|
| 4. |
- Abate, E., et al.
(författare)
-
Combined performance tests before installation of the ATLAS Semiconductor and Transition Radiation Tracking Detectors
- 2008
-
Ingår i: Journal of Instrumentation. - 1748-0221. ; 3
-
Tidskriftsartikel (refereegranskat)abstract
- The ATLAS (A Toroidal LHC ApparatuS) Inner Detector provides charged particle tracking in the centre of the ATLAS experiment at the Large Hadron Collider (LHC). The Inner Detector consists of three subdetectors: the Pixel Detector, the Semiconductor Tracker (SCT), and the Transition Radiation Tracker (TRT). This paper summarizes the tests that were carried out at the final stage of SCT+TRT integration prior to their installation in ATLAS. The combined operation and performance of the SCT and TRT barrel and endcap detectors was investigated through a series of noise tests, and by recording the tracks of cosmic rays. This was a crucial test of hardware and software of the combined tracker detector systems. The results of noise and cross-talk tests on the SCT and TRT in their final assembled configuration, using final readout and supply hardware and software, are reported. The reconstruction and analysis of the recorded cosmic tracks allowed testing of the offline analysis chain and verification of basic tracker performance parameters, such as efficiency and spatial resolution, in combined operation before installation.
|
|
| 5. |
|
|
| 6. |
- Achterberg, A., et al.
(författare)
-
The search for muon neutrinos from northern hemisphere gamma-ray bursts with AMANDA
- 2008
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 674:1, s. 357-370
-
Tidskriftsartikel (refereegranskat)abstract
- We present the results of the analysis of neutrino observations by the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated with photon observations of more than 400 gamma-ray bursts (GRBs) in the northern hemisphere from 1997 to 2003. During this time period, AMANDA's effective collection area for muon neutrinos was larger than that of any other existing detector. After the application of various selection criteria to our data, we expect similar to 1 neutrino event and <2 background events. Based on our observations of zero events during and immediately prior to the GRBs in the data set, we set the most stringent upper limit on muon neutrino emission correlated with GRBs. Assuming a Waxman-Bahcall spectrum and incorporating all systematic uncertainties, our flux upper limit has a normalization at 1 PeV of E-2 Phi(nu) <= 6.3 x 10(-9) GeV cm(-2) s(-1) sr(-1), with 90% of the events expected within the energy range of similar to 10 TeV to similar to 3 PeV. The impact of this limit on several theoretical models of GRBs is discussed, as well as the future potential for detection of GRBs by next-generation neutrino telescopes. Finally, we briefly describe several modifications to this analysis in order to apply it to other types of transient point sources.
|
|
| 7. |
- Casolino, M., et al.
(författare)
-
Cosmic-ray observations of the heliosphere with the PAMELA experiment
- 2006
-
Ingår i: Astrophysics. - : Elsevier BV. ; , s. 1848-1852
-
Konferensbidrag (refereegranskat)abstract
- The PAMELA experiment is a multi-purpose apparatus built around a permanent magnet spectrometer, with the main goal of studying in detail the antiparticle component of cosmic rays. The apparatus will be carried in space by means of a Russian satellite, due to launch in 2005, for a three year-long mission. The characteristics of the detectors composing the instrument, alongside the long lifetime of the mission and the orbital characteristics of the satellite, will allow to address several items of cosmic-ray physics. In this paper, we will focus on the solar and heliospheric observation capabilities of PAMELA.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
- Stozhkov, Y. I., et al.
(författare)
-
About Separation of Hadron and Electromagnetic Cascades in the Pamela Calorimeter
- 2005
-
Ingår i: International Journal of Modern Physics A. - 0217-751X .- 1793-656X. ; 20:29, s. 6745-6748
-
Tidskriftsartikel (refereegranskat)abstract
- Results of calibration of the PAMELA instrument at the CERN facilities are discussed. In September, 2003, the calibration of the Neutron Detector together with the Calorimeter was performed with the CERN beams of electrons and protons with energies of 20-180 GeV. The implementation of the Neutron Detector increases a rejection factor of hadrons from electrons about ten times. The results of calibration are in agreement with calculations.
|
|
| 11. |
|
|
| 12. |
- Abbadessa, G, et al.
(författare)
-
Unsung hero Robert C. Gallo
- 2009
-
Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 323:5911, s. 206-207
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Pittori, C., et al.
(författare)
-
First AGILE catalog of high-confidence gamma-ray sources
- 2009
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 506:3, s. 1563-1574
-
Tidskriftsartikel (refereegranskat)abstract
- We present the first catalog of high-confidence gamma-ray sources detected by the AGILE satellite during observations performed from July 9, 2007 to June 30, 2008. Cataloged sources were detected by merging all the available data over the entire time period. AGILE, launched in April 2007, is an ASI mission devoted to gamma-ray observations in the 30 MeV-50 GeV energy range, with simultaneous X-ray imaging capability in the 18-60 keV band. This catalog is based on Gamma-Ray Imaging Detector (GRID) data for energies greater than 100 MeV. For the first AGILE catalog, we adopted a conservative analysis, with a high-quality event filter optimized to select gamma-ray events within the central zone of the instrument field of view (radius of 40 degrees). This is a significance-limited (4 sigma) catalog, and it is not a complete flux-limited sample due to the non-uniform first-year AGILE sky coverage. The catalog includes 47 sources, 21 of which are associated with confirmed or candidate pulsars, 13 with blazars (7 FSRQ, 4 BL Lacs, 2 unknown type), 2 with HMXRBs, 2 with SNRs, 1 with a colliding-wind binary system, and 8 with unidentified sources.
|
|
| 16. |
- Brand, P L P, et al.
(författare)
-
Definition, assessment and treatment of wheezing disorders in preschool children: an evidence-based approach.
- 2008
-
Ingår i: The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology. - : European Respiratory Society (ERS). - 1399-3003. ; 32:4, s. 1096-110
-
Forskningsöversikt (refereegranskat)abstract
- There is poor agreement on definitions of different phenotypes of preschool wheezing disorders. The present Task Force proposes to use the terms episodic (viral) wheeze to describe children who wheeze intermittently and are well between episodes, and multiple-trigger wheeze for children who wheeze both during and outside discrete episodes. Investigations are only needed when in doubt about the diagnosis. Based on the limited evidence available, inhaled short-acting beta(2)-agonists by metered-dose inhaler/spacer combination are recommended for symptomatic relief. Educating parents regarding causative factors and treatment is useful. Exposure to tobacco smoke should be avoided; allergen avoidance may be considered when sensitisation has been established. Maintenance treatment with inhaled corticosteroids is recommended for multiple-trigger wheeze; benefits are often small. Montelukast is recommended for the treatment of episodic (viral) wheeze and can be started when symptoms of a viral cold develop. Given the large overlap in phenotypes, and the fact that patients can move from one phenotype to another, inhaled corticosteroids and montelukast may be considered on a trial basis in almost any preschool child with recurrent wheeze, but should be discontinued if there is no clear clinical benefit. Large well-designed randomised controlled trials with clear descriptions of patients are needed to improve the present recommendations on the treatment of these common syndromes.
|
|
| 17. |
- Cassou, K., et al.
(författare)
-
Optimization toward a high-average-brightness soft-x-ray laser pumped at grazing incidence
- 2007
-
Ingår i: Optics Letters. - 0146-9592. ; 32:2, s. 139-141
-
Tidskriftsartikel (refereegranskat)abstract
- We report the near-field imaging characterization of a 10 Hz Ni-like 18.9 nm molybdenum soft-x-ray laser pumped in a grazing incidence pumping (GRIP) geometry with a table-top laser driver. We investigate the effect of varying the GRIP angle on the spatial behavior of the soft-x-ray laser source. After multiparameter optimization, we were able to find conditions to generate routinely a high-repetition-rate soft-x-ray laser with an energy level of up to 3 mu J/pulse and to 6 x 10(17) photons/s/mm(2)/mrad(2)/(0.1% bandwidth) average brightness and 1 x 10(28) photons/s/mm(2)/mrad(2)/(0.1% bandwidth) peak brightness. (c) 2006 Optical Society of America.
|
|
| 18. |
- Kazamias, S, et al.
(författare)
-
Characterization of a transient collisional Ni-like molybdenum soft x-ray laser pumped in grazing incidence
- 2008
-
Ingår i: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 77:3
-
Tidskriftsartikel (refereegranskat)abstract
- We present experimental results from an extensive investigation of a Ni-like Mo X-ray laser pumped in the transient regime and GRIP configuration (GRazing Incidence Pumping). The pump laser is a 10 Hz, 1 J, Ti:Sa laser system. The main diagnostic is a monochromatic near-field imaging system with a 1.7 micron spatial resolution that shows the soft x-ray laser source size and position relative to the target surface. Changes of those characteristics are observed for different GRIP angles, varied between 15◦ and 21◦, while keeping all other parameters constant. Intense lasing is observed routinely at 18.9 nm with up to 3 microjoule output energy and stable operation is demonstrated at 10 Hz. We have investigated the role of several pumping parameters, in particular the relative energy and delay between the long and short pulse. We show that this multi-parameter scan leads to a well-defined optimal regime of operation and better understanding of the GRIP configuration. Finally, as the GRIP scheme requires careful tailoring of the plasma conditions to the specific soft x-ray laser under investigation, we add a prepulse before the plasma producing long pulse to generate large-scale preplasmas. This increases the brightness of the soft x-ray beam and leads to an almost gaussian near-field spatial profile.
|
|
| 19. |
|
|
| 20. |
- Lindau, Filip, et al.
(författare)
-
Quantitative study of 10 Hz operation of a soft x-ray laser-energy stability and target considerations
- 2007
-
Ingår i: Optics Express. - 1094-4087. ; 15:15, s. 9486-9493
-
Tidskriftsartikel (refereegranskat)abstract
- A soft x- ray laser from Ni- like Mo, pumped in grazing incidence ( GRIP), is analyzed with regard to high repetition rate operation. Reliable lasing is obtained, but with significant energy fluctuations attributed mainly to beam pointing jitter from the pump laser. Two modes of operation are compared: continuously moving target and stationary target. With a moving target the soft X- ray output is constant on average, whereas the repeated use of the same target position leads to a pulse energy which increases for several tens of shots. This effect might be caused by improved guiding of the pump laser in the formed groove and the removal, through laser ablation, of the oxide layer on the target surface. (c) 2007 Optical Society of America.
|
|
| 21. |
|
|
| 22. |
- de Rossi, S., et al.
(författare)
-
Longitudinal mode selection in constricted photonic crystal guides and electrically injected lasers
- 2005
-
Ingår i: Journal of Lightwave Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 0733-8724 .- 1558-2213. ; 23:3, s. 1363-1368
-
Tidskriftsartikel (refereegranskat)abstract
- Locally reducing the width of a wide photonic crystal (PhC) waveguide generates a constriction which acts as an internal reflector. We have simulated and measured the spectral behavior of a wide PhC waveguide locally constricted to a narrower PhC waveguide and ended by two cleaved facets, thus generating two coupled cavities. Passive structures as well as electrically injected active structures have been investigated. The multimode behavior of wide PhC waveguides is evidenced to play a deciding role. Modal reflection and transmission at the constriction are simulated and measured on passive PhC waveguides, when varying the constrictions' hole size and length. The spectral behavior of full-PhC electrically pumped lasers including such a constriction is measured and analyzed according to the constriction geometry. Design rules are finally proposed to take advantage of this coupled-cavities behavior for high rejection and high external efficiency monomode laser operation.
|
|
| 23. |
- Forte, A, et al.
(författare)
-
c-Myc antisense oligonucleotides preserve smooth muscle differentiation and reduce negative remodelling following rat carotid arteriotomy
- 2005
-
Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 42:3, s. 214-225
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: The vascular biology of restenosis is complex and not fully understood, thus explaining the lack of effective therapy for its prevention in clinical settings. The role of c-Myc in arteriotomy-induced stenosis, smooth muscle cell (SMC) differentiation and apoptosis was investigated in rat carotids applying full phosphorothioate antisense ( AS) oligonucleotides (ODNs). Methods: Carotid arteries from WKY rats were submitted to arteriotomy and to local application of ODNs through pluronic gel. Apoptosis ( deoxynucleotidyl transferase-mediated dUTP nick end-labelling), SMC differentiation (SM22 immunofluorescence) and vessel morphology and morphometry ( image analysis) were determined 2, 5 and 30 days after injury, respectively. Results: AS ODNs induced a 60% decrease of target c-Myc mRNA 4 h after surgery in comparison to control sense ( S) and scrambled ODN-treated carotids (p < 0.05). A significant 37 and 50% decrease in SM22 protein in the media of S ODN-treated and untreated carotids was detected when compared to uninjured contralateral arteries (p < 0.05). This reduction in SM22 expression was prevented in AS ODN-treated carotids. Stenosis was mainly due to adventitial constrictive remodelling. Lumen area in AS ODN-treated carotids was 35% greater than in control arteries 30 days after surgery (p < 0.05). TUNEL assay revealed increased apoptosis in AS ODN-treated carotids (p < 0.05). Conclusions: c-Myc AS ODNs reduce arteriotomy-induced negative remodelling. This is accompanied by maintained SMC differentiation and greater apoptosis. The combination of reduced c-Myc-induced proliferation and increased apoptosis may thus underlie the less severe remodelling upon treatment with c-Myc mRNA AS ODN.
|
|
