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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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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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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 Complex Time Structures in the Cosmic-Ray Electron and Positron Fluxes with the Alpha Magnetic Spectrometer on the International Space Station
/ Aguilar, M (Madrid, CIEMAT) ; Cavasonza, L Ali (IAS, Julich ; JCHP, Julich) ; 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) ; Barrau, A (LPSC, Grenoble) et al.
/AMS
We present high-statistics, precision measurements of the detailed time and energy dependence of the primary cosmic-ray electron flux and positron flux over 79 Bartels rotations from May 2011 to May 2017 in the energy range from 1 to 50 GeV. For the first time, the charge-sign dependent modulation during solar maximum has been investigated in detail by leptons alone. [...]
2018 - 8 p.
- Published in : Phys. Rev. Lett. 121 (2018) 051102
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Towards Understanding the Origin of Cosmic-Ray Electrons
/ 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) ; Azzarello, P (Geneva U.) ; Bachlechner, A (IAS, Julich ; JCHP, Julich) ; Barao, F (LIP, Lisbon) ; Barrau, A (LPSC, Grenoble) et al.
/AMS
Precision results on cosmic-ray electrons are presented in the energy range from 0.5 GeV to 1.4 TeV based on 28.1×106 electrons collected by the Alpha Magnetic Spectrometer on the International Space Station. In the entire energy range the electron and positron spectra have distinctly different magnitudes and energy dependences. [...]
2019 - 9 p.
- Published in : Phys. Rev. Lett. 122 (2019) 101101
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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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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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Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer
/ AMS Collaboration
We report the observation of new properties of primary iron (Fe) cosmic rays in the rigidity range 2.65 GV to 3.0 TV with 0.62×10$^6$ iron nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. Above 80.5 GV the rigidity dependence of the cosmic ray Fe flux is identical to the rigidity dependence of the primary cosmic ray He, C, and O fluxes, with the Fe/O flux ratio being constant at 0.155±0.006. [...]
2021 - 8 p.
- Published in : Phys. Rev. Lett. 126 (2021) 041104
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