Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer

M. Aguilar , L. Ali Cavasonza , G. Ambrosi , L. Arruda , N. Attig , A. Bachlechner , F. Barao , A. Barrau (1) , L. Barrin , A. Bartoloni , S. Başeğmez-Du Pree , R. Battiston , U. Becker , M. Behlmann , B. Beischer , J. Berdugo , B. Bertucci , V. Bindi , W. de Boer , K. Bollweg , B. Borgia , M.J. Boschini , M. Bourquin , E.F. Bueno , J. Burger , W.J. Burger , X.D. Cai , M. Capell , S. Caroff (2) , J. Casaus , G. Castellini , F. Cervelli , Y.H. Chang , G.M. Chen , H.S. Chen , Y. Chen , L. Cheng , H.Y. Chou , V. Choutko , C.H. Chung , C. Clark , G. Coignet (2) , C. Consolandi , A. Contin , C. Corti , Z. Cui , K. Dadzie , Y.M. Dai , A. Datta , C. Delgado , S. Della Torre , M.B. Demirköz , L. Derome (1) , S. Di Falco , V. Di Felice , C. Díaz , F. Dimiccoli , P. von Doetinchem , F. Dong , F. Donnini , M. Duranti , A. Egorov , A. Eline , J. Feng , E. Fiandrini , P. Fisher , V. Formato , Y. Galaktionov , C. Gámez , R.J. García-López , C. Gargiulo , H. Gast , I. Gebauer , M. Gervasi , F. Giovacchini , D.M. Gómez-Coral , J. Gong , C. Goy (2) , V. Grabski , D. Grandi , M. Graziani , K.H. Guo , S. Haino , K.C. Han , Z.H. He , T.H. Hsieh , H. Huang , Z.C. Huang , M. Incagli , W.Y. Jang , Yi Jia , H. Jinchi , K. Kanishev , B. Khiali , G.N. Kim , Th. Kirn , M. Konyushikhin , O. Kounina , A. Kounine , V. Koutsenko , A. Kulemzin , G. La Vacca , E. Laudi , G. Laurenti , I. Lazzizzera , A. Lebedev , H.T. Lee , S.C. Lee , J.Q. Li , Q. Li , T.X. Li , Z.H. Li , C. Light , C.H. Lin , T. Lippert , Z. Liu , S.Q. Lu , Y.S. Lu , K. Luebelsmeyer , F. Luo , J.Z. Luo , Xi Luo , S.S. Lyu , F. Machate , C. Mañá , J. Marín , T. Martin , G. Martínez , N. Masi , D. Maurin (1) , A. Menchaca-Rocha , Q. Meng , D.C. Mo , M. Molero , P. Mott , L. Mussolin , T. Nelson , J.Q. Ni , N. Nikonov , F. Nozzoli , A. Oliva , M. Orcinha , M. Palermo , F. Palmonari , M. Paniccia , A. Pashnin , M. Pauluzzi , S. Pensotti , H.D. Phan , V. Plyaskin , V. Poireau (2) , S. Poluianov , A. Popkow , X.M. Qi , X. Qin , Z.Y. Qu , L. Quadrani , P.G. Rancoita , D. Rapin , A. Reina Conde , S. Rosier-Lees (2) , A. Rozhkov , D. Rozza , R. Sagdeev , S. Schael , S.M. Schmidt , A. Schulz von Dratzig , G. Schwering , E.S. Seo , B.S. Shan , J.Y. Shi , T. Siedenburg , C. Solano , J.W. Song , Z.T. Sun , M. Tacconi , X.W. Tang , Z.C. Tang , J. Tian , Samuel C.C. Ting , S.M. Ting , N. Tomassetti , J. Torsti , C. Tüysüz , T. Urban , I. Usoskin , V. Vagelli , R. Vainio , E. Valente , E. Valtonen , M. Vázquez Acosta , M. Vecchi , M. Velasco , J.P. Vialle (2) , L.Q. Wang , N.H. Wang , Q.L. Wang , X.Q. Wang , Z.X. Wang , J. Wei , Z.L. Weng , H. Wu , R.Q. Xiong , W. Xu , Q. Yan , Y. Yang , H. Yi , Y.J. Yu , Z.Q. Yu , M. Zannoni , S. Zeissler , C. Zhang , F. Zhang , J.H. Zhang , Z. Zhang , F. Zhao , Z.M. Zheng , H.L. Zhuang , V. Zhukov , A. Zichichi , N. Zimmermann , P. Zuccon

1 LPSC - Laboratoire de Physique Subatomique et de Cosmologie
2 LAPP - Laboratoire d'Annecy de Physique des Particules

Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of $^{3}He$ and $^{4}He$ fluxes are presented. The measurements are based on 100 million $^{4}He$ nuclei in the rigidity range from 2.1 to 21 GV and 18 million He3 from 1.9 to 15 GV collected from May 2011 to November 2017. We observed that the $^{3}He$ and $^{4}He$ fluxes exhibit nearly identical variations with time. The relative magnitude of the variations decreases with increasing rigidity. The rigidity dependence of the $^{3}He/^{4}He$ flux ratio is measured for the first time. Below 4 GV, the $^{3}He/^{4}He$ flux ratio was found to have a significant long-term time dependence. Above 4 GV, the $^{3}He/^{4}He$ flux ratio was found to be time independent, and its rigidity dependence is well described by a single power law $\alpha R^{\Delta}$ with $\Delta=-0.294±0.004$. Unexpectedly, this value is in agreement with the B/O and B/C spectral indices at high energies.

Mots clés: Gravitation and Astrophysics; flux: ratio; flux: ratio: measured; energy: high; magnetic spectrometer; time dependence; satellite; spectral; nucleus; helium; AMS

Domaines: Astrophysique [astro-ph]; Physique des Hautes Energies - Expérience [hep-ex]

M. Aguilar, L. Ali Cavasonza, G. Ambrosi, L. Arruda, N. Attig, et al.. Properties of Cosmic Helium Isotopes Measured by the Alpha Magnetic Spectrometer. Physical Review Letters, 2019, 123 (18), pp.181102. ⟨10.1103/PhysRevLett.123.181102⟩. ⟨hal-02382018⟩