A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200GeV the positron fraction no longer exhibits an increase with energy.

High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5-500 GeV with the Alpha Magnetic Spectrometer on the International Space Station / L. Accardo, M. Aguilar, D. Aisa, B. Alpat, A. Alvino, G. Ambrosi, K. Andeen, L. Arruda, N. Attig, P. Azzarello, A. Bachlechner, F. Barao, A. Barrau, L. Barrin, A. Bartoloni, L. Basara, M. Battarbee, R. Battiston, J. Bazo, U. Becker, M. Behlmann, B. Beischer, J. Berdugo, B. Bertucci, G. Bigongiari, V. Bindi, S. Bizzaglia, M. Bizzarri, G. Boella, W. De Boer, K. Bollweg, V. Bonnivard, B. Borgia, S. Borsini, M.J. Boschini, M. Bourquin, J. Burger, F. Cadoux, X.D. Cai, M. Capell, S. Caroff, G. Carosi, J. Casaus, V. Cascioli, G. Castellini, I. Cernuda, D. Cerreta, F. Cervelli, M.J. Chae, Y.H. Chang, A.I. Chen, H. Chen, G.M. Cheng, H.S. Chen, L. Cheng, A. Chikanian, H.Y. Chou, E. Choumilov, V. Choutko, C.H. Chung, F. Cindolo, C. Clark, R. Clavero, G. Coignet, C. Consolandi, A. Contin, C. Corti, B. Coste, Z. Cui, M. Dai, C. Delgado, S. Della Torre, M.B. Demirkoz, L. Derome, S. Di Falco, L. Di Masso, F. Dimiccoli, C. Diaz, P. Von Doetinchem, W.J. Du, M. Duranti, D. D'Urso, A. Eline, F.J. Eppling, T. Eronen, Y.Y. Fan, L. Farnesini, J. Feng, E. Fiandrini, A. Fiasson, E. Finch, P. Fisher, Y. Galaktionov, G. Gallucci, B. Garcia, R. Garcia-Lopez, H. Gast, I. Gebauer, M. Gervasi, A. Ghelfi, W. Gillard, F. Giovacchini, P. Goglov, J. Gong, C. Goy, V. Grabski, D. Grandi, M. Graziani, C. Guandalini, I. Guerri, K.H. Guo, D. Haas, M. Habiby, S. Haino, K.C. Han, Z.H. He, M. Heil, R. Henning, J. Hoffman, T.H. Hsieh, Z.C. Huang, C. Huh, M. Incagli, M. Ionica, W.Y. Jang, H. Jinchi, K. Kanishev, G.N. Kim, K.S. Kim, T. Kirn, R. Kossakowski, O. Kounina, A. Kounine, V. Koutsenko, M.S. Krafczyk, S. Kunz, G. La Vacca, E. Laudi, G. Laurenti, I. Lazzizzera, A. Lebedev, H.T. Lee, S.C. Lee, C. Leluc, G. Levi, H.L. Li, J.Q. Li, Q. Li, Q. Li, T.X. Li, W. Li, Y. Li, Z.H. Li, Z.Y. Li, S. Lim, C.H. Lin, P. Lipari, T. Lippert, D. Liu, H. Liu, M. Lolli, T. Lomtadze, M.J. Lu, Y.S. Lu, K. Luebelsmeyer, F. Luo, J.Z. Luo, S.S. Lv, R. Majka, A. Malinin, C. Mana, J. Marin, T. Martin, G. Martinez, N. Masi, F. Massera, D. Maurin, A. Menchaca-Rocha, Q. Meng, D.C. Mo, B. Monreal, L. Morescalchi, P. Mott, M. Muller, J.Q. Ni, N. Nikonov, F. Nozzoli, P. Nunes, A. Obermeier, A. Oliva, M. Orcinha, F. Palmonari, C. Palomares, M. Paniccia, A. Papi, M. Pauluzzi, E. Pedreschi, S. Pensotti, R. Pereira, R. Pilastrini, F. Pilo, A. Piluso, C. Pizzolotto, V. Plyaskin, M. Pohl, V. Poireau, E. Postaci, A. Putze, L. Quadrani, X.M. Qi, P.G. Rancoita, D. Rapin, J.S. Ricol, I. Rodriguez, S. Rosier-Lees, L. Rossi, A. Rozhkov, D. Rozza, G. Rybka, R. Sagdeev, J. Sandweiss, P. Saouter, C. Sbarra, S. Schael, S.M. Schmidt, D. Schuckardt, A. Schulz Von Dratzig, G. Schwering, G. Scolieri, E.S. Seo, B.S. Shan, Y.H. Shan, J.Y. Shi, X.Y. Shi, Y.M. Shi, T. Siedenburg, D. Son, F. Spada, F. Spinella, W. Sun, W.H. Sun, M. Tacconi, C.P. Tang, X.W. Tang, Z.C. Tang, L. Tao, D. Tescaro, S.C.C. Ting, S.M. Ting, N. Tomassetti, J. Torsti, C. Turkotlu, T. Urban, V. Vagelli, E. Valente, C. Vannini, E. Valtonen, S. Vaurynovich, M. Vecchi, M. Velasco, J.P. Vialle, V. Vitale, G. Volpini, L.Q. Wang, Q.L. Wang, R.S. Wang, X. Wang, Z.X. Wang, Z.L. Weng, K. Whitman, J. Wienkenhover, H. Wu, K.Y. Wu, X. Xia, M. Xie, S. Xie, R.Q. Xiong, G.M. Xin, N.S. Xu, W. Xu, Q. Yan, J. Yang, M. Yang, Q.H. Ye, H. Yi, Y.J. Yu, Z.Q. Yu, S. Zeissler, J.H. Zhang, M.T. Zhang, X.B. Zhang, Z. Zhang, Z.M. Zheng, F. Zhou, H.L. Zhuang, V. Zhukov, A. Zichichi, N. Zimmermann, P. Zuccon, C. Zurbach. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 113:12(2014), pp. 121101.1-121101.17.

High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5-500 GeV with the Alpha Magnetic Spectrometer on the International Space Station

L. Rossi;G. Volpini;
2014

Abstract

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200GeV the positron fraction no longer exhibits an increase with energy.
Time-of-flight; fast trigger; dark-matter; AMS-02 TRD; detector; prototype; electrons; spectrum; models; origin
Settore FIS/01 - Fisica Sperimentale
2014
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/665315
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