| 1. |
- von Doetinchem, P., et al.
(författare)
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Cosmic-ray antinuclei as messengers of new physics : status and outlook for the new decade
- 2020
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; :8
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Tidskriftsartikel (refereegranskat)abstract
- The precise measurement of cosmic-ray antinuclei serves as an important means for identifying the nature of dark matter and other new astrophysical phenomena, and could be used with other cosmic-ray species to understand cosmic-ray production and propagation in the Galaxy. For instance, low-energy antideuterons would provide a "smoking gun" signature of dark matter annihilation or decay, essentially free of astrophysical background. Studies in recent years have emphasized that models for cosmic-ray antideuterons must be considered together with the abundant cosmic antiprotons and any potential observation of antihelium. Therefore, a second dedicated Antideuteron Workshop was organized at UCLA in March 2019, bringing together a community of theorists and experimentalists to review the status of current observations of cosmic-ray antinuclei, the theoretical work towards understanding these signatures, and the potential of upcoming measurements to illuminate ongoing controversies. This review aims to synthesize this recent work and present implications for the upcoming decade of antinuclei observations and searches. This includes discussion of a possible dark matter signature in the AMS-02 antiproton spectrum, the most recent limits from BESS Polar-II on the cosmic antideuteron flux, and reports of candidate antihelium events by AMS-02; recent collider and cosmic-ray measurements relevant for antinuclei production models; the state of cosmic-ray transport models in light of AMS-02 and Voyager data; and the prospects for upcoming experiments, such as GAPS. This provides a roadmap for progress on cosmic antinuclei signatures of dark matter in the coming years.
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| 2. |
- Panico, B., et al.
(författare)
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Cosmic Rays Investigation by the PAMELA experiment
- 2020
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Ingår i: Journal of Physics. - : IOP Publishing.
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Konferensbidrag (refereegranskat)abstract
- PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) is a satellite-borne experiment. It was launched on June 15th 2006 from the Baikonur space centre on board the Russian Resurs-DK1 satellite. For about 10 years PAMELA took data, giving a fundamental contribution to the cosmic ray physics. It made high-precision measurements of the charged component of the cosmic radiation challenging the standard model of the mechanisms of production, acceleration and propagation of cosmic rays in the galaxy and in the heliosphere. PAMELA gave results on different topics on a very wide range of energy. Moreover, the long PAMELA life gives the possibility to study the variation of the proton, electron and positron spectra during the last solar minimum. The time dependence of the cosmic-ray proton and helium nuclei from the solar minimum through the following period of solar maximum activity is currently being studied. Low energy particle spectra were accurately measured also for various solar events that occurred during the PAMELA mission. In this paper a review of main PAMELA results will be reported.
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| 3. |
- Panico, B., et al.
(författare)
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Time dependence of the proton and helium flux measured by PAMELA
- 2020
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Ingår i: Journal of Physics. - : IOP Publishing.
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Konferensbidrag (refereegranskat)abstract
- The energy spectra of galactic cosmic rays carry fundamental information regarding their origin and propagation, but, near Earth, cosmic rays are significantly affected by the solar magnetic field which changes over time. The time dependence of proton and electron spectra were measured from July 2006 to December 2009 by PAMELA experiment, that is a ballooon-borne experiment collecting data since 15 June 2006. These studies allowed to obtain a more complete description of the cosmic radiation, providing fundamental information about the transport and modulation of cosmic rays inside the heliosphere. The study of the time dependence of the cosmic-ray protons and helium nuclei from the unusual 23rd solar minimum through the following period of solar maximum activity is presented.
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| 4. |
- Marcelli, N., et al.
(författare)
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Time Dependence of the Flux of Helium Nuclei in Cosmic Rays Measured by the PAMELA Experiment between 2006 July and 2009 December
- 2020
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Ingår i: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 893:2
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Tidskriftsartikel (refereegranskat)abstract
- Precise time-dependent measurements of the Z = 2 component in the cosmic radiation provide crucial information about the propagation of charged particles through the heliosphere. The PAMELA experiment, with its long flight duration (2006 June 15-2016 January 23) and the low energy threshold (80 MeV/n) is an ideal detector for cosmic-ray solar modulation studies. In this paper, the helium nuclei spectra measured by the PAMELA instrument from 2006 July to 2009 December over a Carrington rotation time basis are presented. A state-of-the-art three-dimensional model for cosmic-ray propagation inside the heliosphere was used to interpret the time-dependent measured fluxes. Proton-to-helium flux ratio time profiles at various rigidities are also presented in order to study any features that could result from the different masses and local interstellar spectra shapes.
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