The explanation of the observed baryon asymmetry, i.e., the almost complete absence of antimatter in the visible part of the universe, is one of the most important problems in cosmology. The real asymmetry value can be determined by direct measurements of the fluxes of antinuclei with charges |Z| a (c) 3/4 2 in primary cosmic rays near the Earth. The results of the search for antihelium using data from the PAMELA experiment obtained from June 2006 to December 2009 are presented. No events with a charge of -2 have been detected in the rigidity range of 0.6-600 GV. An upper limit on the antihelium/helium flux ratio has been presented as a function of the energy. An integral upper level of 4.7 x 10(-7) is the lowest limit at rigidities above 14 GV.
Upper limit on the antihelium flux in primary cosmic rays / A. G. Mayorov;A. M. Galper;O. Adriani;G. A. Bazilevskaya;G. Barbarino;R. Bellotti;M. Boezio;E. A. Bogomolov;V. Bonvicini;M. Bongi;L. Bonechi;S. V. Borisov;S. Bottai;A. Bruno;S. Vacci;E. Vannuccini;G. I. Vasiliev;S. A. Voronov;Y. Wu;I. A. Danilchenko;W. Gillard;G. Jerse;G. Zampa;N. Zampa;V. G. Zverev;M. Casolino;D. Campana;R. Carbone;A. V. Karelin;P. Carlson;G. Castellini;F. Cafagna;A. N. Kvashnin;S. V. Koldashov;S. A. Koldobsky;S. Y. Krutkov;A. A. Leonov;V. V. Malakhov;V. Malvezzi;L. Marcelli;W. Menn;V. V. Mikhailov;E. Mocchiutti;N. Mori;N. V. Nikonov;G. Osteria;S. Pizzolotto;P. Papini;M. P. De;P. Picozza;M. Pearce;M. Riccil;S. Ricciarini;M. F. Runtso;M. Simon;N. D. Simone;R. Sparvoli;P. Spillantini;Y. I. Stozhkov;V. D. Felice;Y. T. Yurkin. - In: JETP LETTERS. - ISSN 0021-3640. - STAMPA. - 93:(2011), pp. 628-631. [10.1134/S0021364011110087]
Upper limit on the antihelium flux in primary cosmic rays
ADRIANI, OSCAR;BONGI, MASSIMO;BONECHI, LORENZO;MORI, NICOLA;SPILLANTINI, PIERO;
2011
Abstract
The explanation of the observed baryon asymmetry, i.e., the almost complete absence of antimatter in the visible part of the universe, is one of the most important problems in cosmology. The real asymmetry value can be determined by direct measurements of the fluxes of antinuclei with charges |Z| a (c) 3/4 2 in primary cosmic rays near the Earth. The results of the search for antihelium using data from the PAMELA experiment obtained from June 2006 to December 2009 are presented. No events with a charge of -2 have been detected in the rigidity range of 0.6-600 GV. An upper limit on the antihelium/helium flux ratio has been presented as a function of the energy. An integral upper level of 4.7 x 10(-7) is the lowest limit at rigidities above 14 GV.I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.