@article{84f46733db8640a09ceb8f2d4d04773f,
title = "Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station",
abstract = "A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×105 antiproton events and 2.42×109 proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500 GV, the antiproton p, proton p, and positron e+ fluxes are found to have nearly identical rigidity dependence and the electron e- flux exhibits a different rigidity dependence. Below 60 GV, the (p/p), (p/e+), and (p/e+) flux ratios each reaches a maximum. From ∼60 to ∼500 GV, the (p/p), (p/e+), and (p/e+) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.",
author = "{(AMS Collaboration)} and M. Aguilar and {Ali Cavasonza}, L. and B. Alpat and G. Ambrosi and L. Arruda and N. Attig and S. Aupetit and P. Azzarello and A. Bachlechner and F. Barao and A. Barrau and L. Barrin and A. Bartoloni and L. Basara and {Ba{\c s}ecmez-Du Pree}, S. and M. Battarbee and R. Battiston and J. Bazo and U. Becker and M. Behlmann and B. Beischer and J. Berdugo and B. Bertucci and V. Bindi and G. Boella and {De Boer}, W. and K. Bollweg and V. Bonnivard and B. Borgia and Boschini, {M. J.} and M. Bourquin and Bueno, {E. F.} and J. Burger and F. Cadoux and Cai, {X. D.} and M. Capell and S. Caroff and J. Casaus and G. Castellini and I. Cernuda and F. Cervelli and Chae, {M. J.} and Chang, {Y. H.} and Chen, {A. I.} and Chen, {G. M.} and Chen, {H. S.} and L. Cheng and Chou, {H. Y.} and E. Choumilov and V. Choutko and Liqiu Wang",
note = "Funding Information: We thank former NASA Administrator Daniel S. Goldin for his dedication to the legacy of the ISS as a scientific laboratory and his decision for NASA to fly AMS as a DOE payload. We also acknowledge the continuous support of the NASA leadership including Charles Bolden and William H. Gerstenmaier and of the JSC and MSFC flight control teams which has allowed AMS to operate optimally on the ISS for five years. We are grateful for the support of Jim Siegrist and his staff of the DOE. We also acknowledge the continuous support from MIT and its School of Science, Michael Sipser, Marc Kastner, Ernest Moniz, Richard Milner, and Boleslaw Wyslouch. Research supported by Sao Paulo Research Foundation (FAPESP) Grants No. 2014/19149-7, No. 2014/50747-8, and No. 2015-50378-5, Brazil; CAS, NSFC, MOST, NLAA, the provincial governments of Shandong, Jiangsu, Guangdong, and the China Scholarship Council, China; the Finnish Funding Agency for Innovation (Tekes) Grants No. 40361/01 and No. 40518/03 and the Academy of Finland Grant No. 258963, Finland; CNRS, IN2P3, CNES, Enigmass, and the ANR, France; Pascale Ehrenfreund, DLR, and JARA-HPC under Project No. JARA0052, Germany; INFN and ASI under ASI-INFN Agreements No. 2013-002-R.0 and No. 2014-037-R.0, Italy; CHEP Grants No. NRF-2009-0080142 and No. NRF-2012-010226 at Kyungpook National University and No. NRF-2013-004883 at Ewha Womans University, Korea; the Consejo Nacional de Ciencia y Tecnologa and UNAM, Mexico; FCT under Grant No. PTDC/FIS/122567/2010, Portugal; CIEMAT, IAC, CDTI, and SEIDI-MINECO under Grants No. AYA2012-39526-C02-(01/02), No. ESP2015-71662-C2-(1-P/2-P), No. SEV-2011-0187, No. SEV-2015-0548, and No. MDM-2015-0509, Spain; the Swiss National Science Foundation (SNSF), federal and cantonal authorities, Switzerland; Academia Sinica and the Ministry of Science and Technology (MOST) under Grants No. 103-2112-M-006-018-MY3, No. 104-2112-M-001-027, and No. CDA-105-M06, former President of Academia Sinica Yuan-Tseh Lee, and former Ministers of MOST Maw-Kuen Wu and Luo-Chuan Lee, Taiwan; the Turkish Atomic Energy Authority at METU, Turkey; and NSF Grant No. 1455202, Wyle Laboratories Grant No. 2014/T72497, and NASA NESSF Grant No. HELIO15F-0005, USA. We gratefully acknowledge the strong support from CERN including Rolf-Dieter Heuer and Fabiola Gianotti, from the CERN IT department and Bernd Panzer-Steindel, and from the European Space Agency including Johann-Dietrich Warner and Simonetta Di Pippo. We are grateful for important discussions with Fiorenza Donato, Jonathan Ellis, Jonathan Feng, Igor Moskalenko, Michael Salamon, Subir Sarkar, Joachim Tramper, Michael S. Turner, Steven Weinberg, and Arnold Wolfendale. Publisher Copyright: {\textcopyright} 2016 authors. Published by the American Physical Society.",
year = "2016",
month = aug,
day = "26",
doi = "10.1103/PhysRevLett.117.091103",
language = "English",
volume = "117",
journal = "Physical Review Letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "9",
}