| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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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.
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| 2. |
- Thomas, HS, et al.
(författare)
-
- 2019
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swepub:Mat__t
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| 3. |
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| 4. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 5. |
- Tinetti, Giovanna, et al.
(författare)
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The EChO science case
- 2015
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Ingår i: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 40:2-3, s. 329-391
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Tidskriftsartikel (refereegranskat)abstract
- The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune-all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10(-4) relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 mu m with a goal of covering from 0.4 to 16 mu m. Only modest spectral resolving power is needed, with R similar to 300 for wavelengths less than 5 mu m and R similar to 30 for wavelengths greater than this. The transit spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m(2) is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m(2) telescope, diffraction limited at 3 mu m has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate than current observations. This would enable the detection of molecular abundances three orders of magnitude lower than currently possible and a fourfold increase from the handful of molecules detected to date. Combining these data with estimates of planetary bulk compositions from accurate measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals. The mission can target super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300-3000 K) of F to M-type host stars. The EChO core science would be delivered by a three-tier survey. The EChO Chemical Census: This is a broad survey of a few-hundred exoplanets, which allows us to explore the spectroscopic and chemical diversity of the exoplanet population as a whole. The EChO Origin: This is a deep survey of a subsample of tens of exoplanets for which significantly higher signal to noise and spectral resolution spectra can be obtained to explain the origin of the exoplanet diversity (such as formation mechanisms, chemical processes, atmospheric escape). The EChO Rosetta Stones: This is an ultra-high accuracy survey targeting a subsample of select exoplanets. These will be the bright "benchmark" cases for which a large number of measurements would be taken to explore temporal variations, and to obtain two and three dimensional spatial information on the atmospheric conditions through eclipse-mapping techniques. If EChO were launched today, the exoplanets currently observed are sufficient to provide a large and diverse sample. The Chemical Census survey would consist of > 160 exoplanets with a range of planetary sizes, temperatures, orbital parameters and stellar host properties. Additionally, over the next 10 years, several new ground- and space-based transit photometric surveys and missions will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO's launch and enable the atmospheric characterisation of hundreds of planets.
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| 6. |
- Casolino, M., et al.
(författare)
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Cosmic-ray observations of the heliosphere with the PAMELA experiment
- 2006
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Ingår i: Astrophysics. - : Elsevier BV. ; , s. 1848-1852
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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.
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| 7. |
- Stozhkov, Y. I., et al.
(författare)
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About Separation of Hadron and Electromagnetic Cascades in the Pamela Calorimeter
- 2005
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Ingår i: International Journal of Modern Physics A. - 0217-751X .- 1793-656X. ; 20:29, s. 6745-6748
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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.
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| 8. |
- Bongi, M, et al.
(författare)
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PAMELA : A satellite experiment for antiparticles measurement in cosmic rays
- 2004
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 51:3, s. 854-859
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Tidskriftsartikel (refereegranskat)abstract
- PAMELA is a satellite-borne experiment that will study the antiproton and positron fluxes in cosmic rays in a wide range of energy (from 80 MeV up to 190 GeV for antiprotons and from 50 MeV up to 270 GeV for positrons) and with high statistics, and that will measure the antihelium/helium ratio with a sensitivity of the order of 10(-8). The detector will fly on-board a polar orbiting Resurs DK1 satellite, which will be launched into space by a Soyuz rocket in 2004 from Baikonur cosmodrome in Kazakhstan, for a 3-year-long mission. Particle identification and energy measurements are performed in the PAMELA apparatus using the following subdetectors: a magnetic spectrometer made up of a permanent magnet equipped with double-sided microstrip silicon detectors, an electromagnetic imaging calorimeter composed of layers of tungsten absorber and silicon detectors planes, a transition radiation detector made of straw tubes interleaved with carbon fiber radiators, a plastic scintillator time-of-flight and trigger system, a set of anticounter plastic scintillator detectors, and a neutron detector. The features of the detectors and the main results obtained in beam test sessions are presented.
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| 9. |
- Casolino, M., et al.
(författare)
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Launch of the space experiment PAMELA
- 2008
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Ingår i: Advances in Space Research. - : Elsevier. - 0273-1177 .- 1879-1948. ; 42:3, s. 455-466
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Tidskriftsartikel (refereegranskat)abstract
- PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature in a wide energy range (protons 80 MeV-700 GeV, electrons 50 MeV-400 GeV). Main objective is the study of the antimatter component: antiprotons (80 MeV-190 GeV), positrons (50 MeV-270 GeV) and search for antimatter with a precision of the order of 10-8. The experiment, housed on board the Russian Resurs-DK I satellite, was launched on June 15th, 2006 in a 350 x 600 km orbit with all inclination of 70'. The detector is composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, time-of-flight, and rigidity information. Lepton/hadron identification is performed by a silicon-tungsten calorimeter and a neutron detector placed at the bottom of the device. An anticounter system is used offline to reject false triggers coming from the satellite. In self-trigger mode the calorimeter, the neutron detector, and a shower tail catcher are capable of an independent measure of the lepton component up to 2 TeV. In this work we describe the experiment, its scientific objectives, and the performance in the first months after launch.
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| 10. |
- Martucci, M., et al.
(författare)
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Analysis on H spectral shape during the early 2012 SEPs with the PAMELA experiment
- 2014
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 742, s. 158-161
-
Tidskriftsartikel (refereegranskat)abstract
- The satellite-borne PAMELA experiment has been continuously collecting data since 2006. This apparatus is designed to study charged particles in the cosmic radiation. The combination of a permanent magnet, a silicon strip tracker and a silicon-tungsten imaging calorimeter, and the redundancy of instrumentation allow very precise studies on the physics of cosmic rays in a wide energy range and with high statistics. This makes PAMELA a very suitable instrument for Solar Energetic Particle (SEP) observations. Not only does it span the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but PAMELA also carries out the first direct measurements of the composition for the highest energy SEP events, including those causing Ground Level Enhancements (GLEs). In particular, PAMELA has registered many SEP events during solar cycle 24, offering unique opportunities to address the question of high-energy SEP origin. A preliminary analysis on proton spectra behaviour during this event is presented in this work.
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| 11. |
- Boezio, M., et al.
(författare)
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The PAMELA space experiment : First year of operation
- 2008
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Ingår i: Journal of Physics, Conference Series. - : Institute of Physics Publishing (IOPP). - 1742-6588 .- 1742-6596. ; 110:6
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Tidskriftsartikel (refereegranskat)abstract
- On the 15th of June 2006 the PAMELA experiment, mounted on the Resurs DK1 satellite, was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. PAMELA is a satellite-borne apparatus designed to study charged particles in the cosmic radiation, to investigate the nature of dark matter, measuring the cosmic-ray antiproton and positron spectra over the largest energy range ever achieved, and to search for antinuclei with unprecedented sensitivity. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. The combination of these devices allows charged particle identification over a wide energy range. © 2008 IOP Publishing Ltd.
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| 12. |
- Casolino, M., et al.
(författare)
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Magnetospheric and solar physics observations with the PAMELA experiment
- 2008
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 588:1-2, s. 243-246
-
Tidskriftsartikel (refereegranskat)abstract
- PAMELA is a satellite-borne experiment designed to make long duration measurements of the cosmic radiation in Low Earth Orbit. It is devoted to the detection of the cosmic-ray spectra in the 100 MeV-300 GeV range with primary scientific goal the measurement of antiproton and positron spectra over the largest energy range ever achieved. Other tasks include the search for antinuclei with unprecedented sensitivity and the measurement of the light nuclear component of cosmic rays. In addition, PAMELA can investigate phenomena connected with solar and Earth physics. The apparatus consists of: a Time of Flight system, a magnetic spectrometer, an electromagnetic imaging calorimeter, a shower tail catcher scintillator, a neutron detector and an anticoincidence system. In this work we present some measurements of galactic, secondary and trapped particles performed in the first months of operation.
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| 13. |
- Ricciarini, S. B., et al.
(författare)
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PAMELA mission : Heralding a new era in cosmic ray physics
- 2014
-
Ingår i: EPJ Web of Conferences. - : EDP Sciences. - 2100-014X.
-
Konferensbidrag (refereegranskat)abstract
- After seven years of data taking in space, the experiment PAMELA is showing very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt.
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| 14. |
- Adriani, O., et al.
(författare)
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The PAMELA space mission
- 2008
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Ingår i: Astroparticle, Part. Space Phys., Detect. Med. Phys. Appl. - Proc. Conf.. - : WORLD SCIENTIFIC. - 9812819088 - 9789812819086 ; , s. 858-864
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Konferensbidrag (refereegranskat)abstract
- The PAMELA (a Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics) experiment, is a satellite-borne particle spectrometer. It was launched on 15th June 2006 from the Baikonur cosmodrome in Kazakhstan, is installed into the Russian Resurs-DK1 satellite. PAMELA is composed of a time-of-flight system, a magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. Among the PAMELA major objectives are the study of charged particles in the cosmic radiation, the investigation of the nature of dark matter, by mean of the measure of the cosmic-ray antiproton and positron spectra over the largest energy range ever achieved. PAMELA has been in a nearly continuous data taking mode since llth July 2006. The status of the apparatus and performances will be presented.
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| 15. |
- Boezio, M., et al.
(författare)
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The first year in orbit of the pamela experiment
- 2007
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Ingår i: Proceedings of the 30th International Cosmic Ray Conference, ICRC 2007. - : Universidad Nacional Autonoma de Mexico. ; , s. 99-102
-
Konferensbidrag (refereegranskat)abstract
- On the 15th of June 2006, the PAMELA experiment mounted on the Resurs DK1 satellite, was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. PAMELA is a satellite-borne apparatus designed to study charged particles in the cosmic radiation, to investigate the nature of dark matter, measuring the cosmic-ray antiproton and positron spectra over the largest energy range ever achieved, and to search for antinuclei with unprecedented sensitivity. The PAMELA apparatus comprises a time-of-flight system, a magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. We will present the status of the apparatus after one year in orbit. Furthermore, we will discuss the PAMELA in-flight performances.
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| 16. |
- Boezio, M., et al.
(författare)
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The PAMELA experiment and antimatter in the universe
- 2014
-
Ingår i: Hyperfine Interactions. - : Springer Science and Business Media LLC. - 0304-3843 .- 1572-9540. ; 228:1-3, s. 101-109
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Tidskriftsartikel (refereegranskat)abstract
- On the 15th of June 2006, the PAMELA satellite-borne experiment was launched from the Baikonur cosmodrome and it has been collecting data since July 2006. The primary scientific goal is the measurement of the antiproton and positron energy spectra. Antiparticles are a natural component of the cosmic radiation being produced in the interaction between cosmic rays and the interstellar matter. They have been shown to be extremely interesting for understanding the propagation mechanisms of cosmic rays. Furthermore, novel sources of primary cosmic-ray antiparticles of either astrophysical or exotic origin (e.g. annihilation of dark matter particles) can also be probed. In this paper we review the PAMELA antiparticle results and their significance for the field of astroparticle physics.
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| 17. |
- Di Felice, V., et al.
(författare)
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Solar modulation of galactic hydrogen and helium over the 23rd solar minimum with the PAMELA experiment
- 2013
-
Ingår i: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
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Konferensbidrag (refereegranskat)abstract
- PAMELA has been orbiting the Earth for more than six years, gathering data on solar, galactic and trapped cosmic rays during the time of the last solar minimum. The apparatus comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer, a silicon-tungsten electromagnetic calorimeter, an anticoincidence system, a shower tail catcher scintillator and a neutron detector. The combination of these devices allows charged particle and antiparticle identification over a wide energy range and with an unprecedented precision. The quasi-polar orbit of the instrument, with an inclination of 70 degrees, makes it possible to measure low energy particles starting from about 100 MeV/n. In this work we present the time and rigidity dependence of the galactic proton and helium fluxes over the first 4 years of operation during the A < 0 solar minimum of solar cycle 23.
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| 18. |
- Formato, V., et al.
(författare)
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Measurement of hydrogen and helium isotopes flux in galactic cosmic rays with the PAMELA experiment
- 2014
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 742, s. 273-275
-
Tidskriftsartikel (refereegranskat)abstract
- PAMELA is a satellite borne experiment designed to study with great accuracy cosmic rays of galactic, solar, and trapped nature, with particular focus on the antimatter component. The detector consists of a permanent magnet spectrometer core to provide rigidity and charge sign information, a Time-of-Flight system for velocity and charge information, a Silicon-Tungsten calorimeter and a Neutron detector for lepton/hadron identification. The velocity and rigidity information allow the identification of different isotopes for Z = 1 and Z = 2 particles in the energy range 100 MeV/n to 1 GeV/n. In this work we will present the PAMELA results on the H and He isotope fluxes based on the data collected during the 23rd solar minimum from 2006 to 2007. Such fluxes carry relevant information helpful in constraining parameters in galactic cosmic rays propagation models complementary to those obtained from other secondary to primary measurements such as the boron-to-carbon ratio.
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| 19. |
- Karelin, A. V., et al.
(författare)
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The high energy cosmic ray particle spectra measurements with the PAMELA calorimeter
- 2016
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Ingår i: Nuclear and Particle Physics Proceedings. - : Elsevier. - 2405-6014. ; 273-275, s. 275-281
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Tidskriftsartikel (refereegranskat)abstract
- Up until now there has been limited, contradictive data on the high energy range of the cosmic ray electron-positron, proton and helium spectra. Due to the limitations of the use of a magnetic spectrometer, over 8 years experimental data was processed using information from a sampling electro-magnetic calorimeter, a neutron detector and scintillator detectors. The use of these devices allowed us to successfully obtain the high energy cosmic ray particle spectra measurements. The results of this study clarify previous findings and greaten our understanding of the origin of cosmic rays.
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| 20. |
- Koldobskiy, S. A., et al.
(författare)
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Galactic deuteron spectrum measured in PAMELA experiment
- 2013
-
Ingår i: 23Rd European Cosmic Ray Symposium (And 32Nd Russian Cosmic Ray Conference). - : IOP Publishing.
-
Konferensbidrag (refereegranskat)abstract
- Results of galactic deuteron spectrum measurement by means of PAMELA apparatus are described. PAMELA is an international experiment developed for antimatter search and measurement of p, He, electron and positron spectra in wide energy range. In addition, PAMELA allows to identify and measure deuteron spectrum at low energies. In this paper deuteron-to-proton ratio and deuteron spectrum are presented.
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| 21. |
- Ricci, M., et al.
(författare)
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Study on 2012 march 7 solar particle event and forbush decrease with the PAMELA experiment
- 2013
-
Ingår i: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Konferensbidrag (refereegranskat)abstract
- The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astro-physics) space-borne experiment was launched on 15 June 2006 and has been continuously collecting data since then. The apparatus measures electrons, positrons, protons, anti-protons and heavier nuclei from about 100 MeV to several hundreds of GeV. The on-board instrumentation is built around a permanent magnet with a silicon microstrip tracker, providing charge and track detection information. During solar maximum conditions of solar cycle 24, PAMELA has been providing key information about solar energetic particles (SEPs) and their influence at Earth. We discuss here the recent 2012 March 7 SEP event with a brief comment on the subsequent Forbush decrease, registered by PAMELA. This event was also observed by Fermi/LAT exhibiting unprecedented time-extended γ-ray emission (> 100 MeV) lasting nearly 20 hours. We compare the derived accelerated ion population at the Sun with the ion population measured in space by PAMELA and discuss the implications for particle acceleration.
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| 22. |
- Adriani, O., et al.
(författare)
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Antiprotons in primary cosmic radiation with PAMELA experiment
- 2013
-
Ingår i: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
-
Konferensbidrag (refereegranskat)abstract
- The latest measurements of antiprotons spectrum and antiproton-to-proton ratio in primary cosmic rays with PAMELA experiment are presented. They are in good agreement with model of secondary production of antiprotons in Galaxy, but they do not completely rule other sources at the high-energies.
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| 23. |
- Adriani, O., et al.
(författare)
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The PAMELA Mission : Heralding a new era in precision cosmic ray physics
- 2014
-
Ingår i: Physics reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 544:4, s. 323-370
-
Forskningsöversikt (refereegranskat)abstract
- On the 15th of June 2006, the PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite-borne experiment was launched onboard the Russian Resurs-DK1 satellite by a Soyuz rocket from the Baikonur space centre. The satellite was placed in a quasi-polar 70 degrees inclination orbit at an altitude varying between 350 km and 600 km. New results on the antiparticle component of the cosmic radiation were obtained. The positron energy spectrum and positron fraction were measured from 400 MeV up to 200 GeV revealing a positron excess over the predictions of commonly used propagation models. This can be interpreted either as evidence that the propagation models should be revised or in terms of dark matter annihilation or a pulsar contribution. The antiproton spectrum was measured over the energy range from 60 MeV to 350 GeV. The antiproton spectrum is consistent with secondary production and significantly constrains dark matter models. The energy spectra of protons and helium nuclei were measured up to 1.2 TV. The spectral shapes of these two species are different and cannot be described well by a single power law. For the First time the electron spectrum was measured up to 600 GeV complementing the information obtained from the positron data. Nuclear and isotopic composition was obtained with unprecedented precision. The variation of the low energy proton, electron and positron energy spectra was measured from July 2006 until December 2009 accurately sampling the unusual conditions of the most recent solar minimum activity period (2006-2009). Low energy particle spectra were accurately measured also for various solar events that occurred during the PAMELA mission. The Earth's magnetosphere was studied measuring the particle radiation in different regions of the magnetosphere. Energy spectra and composition of sub-cutoff and trapped particles were obtained. For the first time a belt of trapped antiprotons was detected in the South Atlantic Anomaly region. The flux was found to exceed that for galactic cosmic-ray antiprotons by three order of magnitude.
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| 24. |
- Bazilevskaya, G. A., et al.
(författare)
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Solar proton events at the end of the 23rd and start of the 24th solar cycle recorded in the PAMELA experiment
- 2013
-
Ingår i: Bulletin of the Russian Academy of Sciences: Physics. - 1062-8738. ; 77:5, s. 493-496
-
Tidskriftsartikel (refereegranskat)abstract
- The PAMELA magnetic spectrometer was launched into a near-Earth orbit on board the Resurs-DK1 satellite in June 2006; in December 2006, it recorded the last strong solar high-energy particle event of the 23rd solar cycle. A deficit was thereafter observed in solar energetic particle events because of the lengthy solar activity minimum and the weak evolution of the next (24th) solar cycle. As a result, only a few solar events involving protons with energies of more than 100 MeV were recorded between 2010 and 1012. This work presents the preliminary results from measurements of charged particle fluxes in these events, recorded by the Pamela spectrometer.
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| 25. |
- Carbone, R., et al.
(författare)
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Pamela observation of the 2012 may 17 gle event
- 2013
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Ingår i: Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013. - : Sociedade Brasileira de Fisica. - 9788589064293
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Konferensbidrag (refereegranskat)abstract
- The PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) satellite-borne experiment has been collecting data in orbit since July 2006, providing accurate measurements of the energy spectra and composition of the cosmic radiation from a few hundred MeV/n up to hundred GeV/n. This wide interval of measured energies makes PAMELA a unique instrument for Solar Energetic Particle (SEP) observations. Not only does it span the energy range between the ground-based neutron monitor data and the observations of SEPs from space, but also PAMELA carries out the first direct measurements of the composition for the highest energy SEP events, including those causing Ground Level Enhancements (GLEs). PAMELA has registered many SEP events in solar cycle 24 including the 2012 May 17 GLE event (GLE 71), offering unique opportunities to address the question of high-energy SEP origin. Experimental performances and preliminary results on the 2012 May 17 events will be presented. We will discuss the derived particle injection time and compare with other time scales at the Sun including the flare and CME onset times.
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