A major feature of the energy spectrum of the cosmic radiation above 1019 eV is the increasing fraction of heavy nuclei with respect to light nuclei. This fact, along with other simple assumptions, is adopted to calcu...A major feature of the energy spectrum of the cosmic radiation above 1019 eV is the increasing fraction of heavy nuclei with respect to light nuclei. This fact, along with other simple assumptions, is adopted to calculate the energy spectrum of the cosmic radiation up to 2.4 × 1021 eV. The predicted spectrum maintains the index of 2.67 observed at lower energies which is the basic, known, empirical well-assessed feature of the physical mechanism accelerating cosmic rays in the Galaxy. Indeed above 1019 eV the injection of nuclei is inhibited by some filter and this inhibition causes a staircase profile of the energy spectrum. It is argued that particle injection failure versus energy commences with protons, followed by Helium and then by other heavier nuclei up to Uranium. Around 7.5 × 1020 the cosmic radiation consists solely of nuclei heavier than Copper and the estimated intensity is 1.8 × 10-30 particles/GeV s sr m2.展开更多
The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3 ± 2.8) × 10^ 6 using J/ψ→inclusive events, where the uncertainty is the syst...The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3 ± 2.8) × 10^ 6 using J/ψ→inclusive events, where the uncertainty is the systematic error and the statistical one is negligible.展开更多
文摘A major feature of the energy spectrum of the cosmic radiation above 1019 eV is the increasing fraction of heavy nuclei with respect to light nuclei. This fact, along with other simple assumptions, is adopted to calculate the energy spectrum of the cosmic radiation up to 2.4 × 1021 eV. The predicted spectrum maintains the index of 2.67 observed at lower energies which is the basic, known, empirical well-assessed feature of the physical mechanism accelerating cosmic rays in the Galaxy. Indeed above 1019 eV the injection of nuclei is inhibited by some filter and this inhibition causes a staircase profile of the energy spectrum. It is argued that particle injection failure versus energy commences with protons, followed by Helium and then by other heavier nuclei up to Uranium. Around 7.5 × 1020 the cosmic radiation consists solely of nuclei heavier than Copper and the estimated intensity is 1.8 × 10-30 particles/GeV s sr m2.
基金Supported by Ministry of Science and Technology of China (2009CB825200)National Natural Science Foundation of China (NSFC) (10625524, 10821063, 10825524, 10835001, 10935007, 11125525)+3 种基金Joint Funds of National Natural Science Foundation of China (11079008, 11179007)Chinese Academy of Sciences (CAS) Large-Scale Scientific Facility Program (KJCX2-YW-N29, KJCX2-YW-N45)100 Talents Program of CAS, Istituto Nazionale di Fisica Nucleare, Italy, U. S. Department of Energy (DE-FG02-04ER41291, DE-FG02-91ER40682, DE-FG02-94ER40823)U.S. National Science Foundation, University of Groningen (RuG) and the Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), Darmstadt, WCU Program of National Research Foundation of Korea (R32-2008-000-10155-0)
文摘The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3 ± 2.8) × 10^ 6 using J/ψ→inclusive events, where the uncertainty is the systematic error and the statistical one is negligible.