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Towards Understanding the Origin of Cosmic-Ray Positrons
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) ; Barrin, L (CERN) et al.
/AMS
Precision measurements of cosmic ray positrons by the Alpha Magnetic Spectrometer on the International Space Station are presented up to 1 TeV based on 1.9 million positrons.The positron flux exhibits a significant excess starting from $25.2 \pm 1.8$ GeV followed by a sharp drop-off above $284^{+91}_{-64}$ GeV.In the entire energy range the positron flux is well described by the sum of a diffuse termassociated with low energy secondary positrons produced in the collision of cosmic rays, and a new source term of high energy positrons with a finite energy cutoff. The finite cutoff energy of the source term, $E_s$, is established with a significance of more than $4 \sigma$, and it's value is determined to be $E_s = 810^{+310}_{-180}$ GeV.These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter collisions or from new astrophysical sources..
2019 - 9 p.
- Published in : Phys. Rev. Lett. 122 (2019) 041102
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Observation of Fine Time Structures in the Cosmic Proton and Helium Fluxes with the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Alpat, B (INFN, Perugia) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) et al.
/AMS
We present the precision measurement from May 2011 to May 2017 (79 Bartels rotations) of the proton fluxes at rigidities from 1 to 60 GV and the helium fluxes from 1.9 to 60 GV based on a total of $1 \times 10^9$ events collected with the Alpha Magnetic Spectrometer aboard the International Space Station. This measurement is in solar cycle 24, which has the solar maximum in April 2014. [...]
2018 - 7 p.
- Published in : Phys. Rev. Lett. 121 (2018) 051101
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Precision Measurement of Cosmic-Ray Nitrogen and its Primary and Secondary Components with the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Alpat, B (INFN, Perugia ; Perugia U.) ; Ambrosi, G (INFN, Perugia ; Perugia U.) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) et al.
/AMS
A precision measurement of the nitrogen flux with rigidity (momentum per unit charge) from 2.2 GV to 3.3 TV based on $2.2 \times 10^6$ events is presented. The detailed rigidity dependence of the nitrogen flux spectral index is presented for the first time. [...]
2018 - 8 p.
- Published in : Phys. Rev. Lett. 121 (2018) 051103
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Observation of New Properties of Secondary Cosmic Rays Lithium, Beryllium, and Boron by the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) et al.
/AMS
We report on the observation of new properties of secondary cosmic rays Li, Be, and B measured in the rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total of $5.4 \times 10^6$ nuclei collected by AMS during the first five years of operation aboard the International Space Station. The Li and B fluxes have an identical rigidity dependence above 7 GV and all three fluxes have an identical rigidity dependence above 30 GV with the Li/Be flux ratio of $2.0 \pm 0.1$. [...]
2018 - 8 p.
- Published in : Phys. Rev. Lett. 120 (2018) 021101
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Observation of the Identical Rigidity Dependence of He, C, and O Cosmic Rays at High Rigidities by the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Ali Cavasonza, L (IAS, Julich ; JCHP, Julich) ; Alpat, B (INFN, Perugia) ; Ambrosi, G (INFN, Perugia) ; Arruda, L (LIP, Lisbon) ; Attig, N (IAS, Julich ; JCHP, Julich) ; Aupetit, S (LPSC, Grenoble) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) et al.
/AMS
We report the observation of new properties of primary cosmic rays He, C, and O measured in the rigidity (momentum/charge) range 2 GV to 3 TV with 90×106 helium, 8.4×106 carbon, and 7.0×106 oxygen nuclei collected by the Alpha Magnetic Spectrometer (AMS) during the first five years of operation. Above 60 GV, these three spectra have identical rigidity dependence. [...]
2017 - 8 p.
- Published in : Phys. Rev. Lett. 119 (2017) 251101
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