{"id":75650,"date":"2023-11-15T10:12:07","date_gmt":"2023-11-15T01:12:07","guid":{"rendered":"https:\/\/www.waseda.jp\/inst\/research\/?p=75650"},"modified":"2023-11-15T10:12:07","modified_gmt":"2023-11-15T01:12:07","slug":"direct-measurement-of-the-spectral-structure-of-cosmic-ray-electronspositrons-in-the-tev-region-with-calet-on-the-international-space-station%ef%bc%88published-in-physical-review-letters-november-20","status":"publish","type":"post","link":"https:\/\/www.waseda.jp\/inst\/research\/news\/75650","title":{"rendered":"Direct Measurement of the Spectral Structure of Cosmic-Ray Electrons+Positrons in the TeV Region with CALET on the International Space Station\uff08Published in Physical Review Letters, November 2023\uff09"},"content":{"rendered":"\n\n\n\n\n\n\n\n\n
Journal Title
\n\/\u63b2\u8f09\u30b8\u30e3\u30fc\u30ca\u30eb\u540d<\/td>\n		Physical Review Letters<\/td>\n<\/tr>\n
Publication Year and Month
\n\/\u63b2\u8f09\u5e74\u6708<\/td>\n		November, 2023<\/td>\n<\/tr>\n
Paper Title
\n\/\u8ad6\u6587\u30bf\u30a4\u30c8\u30eb<\/td>\n		Direct Measurement of the Spectral Structure of Cosmic-Ray Electrons+Positrons in the TeV Region with CALET on the International Space Station<\/td>\n<\/tr>\n
DOI
\n\/\u8ad6\u6587DOI<\/td>\n		10.1103\/PhysRevLett.131.191001<\/a><\/td>\n<\/tr>\n
\u00a0Author of Waseda University
\n\/\u672c\u5b66\u306e\u8457\u8005<\/td>\n		AKAIKE, Yosui(Researcher(Associate Professor), Faculty of Science and Engineering, Waseda Research Institute for Science and Engineering):Correspoinding Author<\/td>\n<\/tr>\n
Related Websites
\n\/\u95a2\u9023Web<\/td>\n		–<\/td>\n<\/tr>\n
Abstract
\n\/\u6284\u9332<\/td>\n		Detailed measurements of the spectral structure of cosmic-ray electrons and positrons from 10.6\u00a0GeV to 7.5\u00a0TeV are presented from over 7\u00a0years of observations with the CALorimetric Electron Telescope (CALET) on the International Space Station. The instrument, consisting of a charge detector, an imaging calorimeter, and a total absorption calorimeter with a total depth of 30\u00a0radiation lengths at normal incidence and a fine shower imaging capability, is optimized to measure the all-electron spectrum well into the TeV region. Because of the excellent energy resolution (a few percent above 10\u00a0GeV) and the outstanding\u00a0e<\/span><\/span>\/<\/span><\/span>p<\/span><\/span><\/span><\/span><\/span><\/span>\u00a0separation (10<\/span><\/span><\/span>5<\/span><\/span><\/span><\/span><\/span><\/span><\/span>), CALET provides optimal performance for a detailed search of structures in the energy spectrum. The analysis uses data up to the end of 2022, and the statistics of observed electron candidates has increased more than 3 times since the last publication in 2018. By adopting an updated boosted decision tree analysis, a sufficient proton rejection power up to 7.5\u00a0TeV is achieved, with a residual proton contamination less than 10%. The observed energy spectrum becomes gradually harder in the lower energy region from around 30\u00a0GeV, consistently with AMS-02, but from 300 to 600\u00a0GeV it is considerably softer than the spectra measured by DAMPE and Fermi-LAT. At high energies, the spectrum presents a sharp break around 1\u00a0TeV, with a spectral index change from\u00a0\u2212<\/span><\/span>3.15<\/span><\/span><\/span><\/span><\/span><\/span>\u00a0to\u00a0\u2212<\/span><\/span>3.91<\/span><\/span><\/span><\/span><\/span><\/span>, and a broken power law fitting the data in the energy range from 30\u00a0GeV to 4.8\u00a0TeV better than a single power law with 6.9 sigma significance, which is compatible with the DAMPE results. The break is consistent with the expected effects of radiation loss during the propagation from distant sources (except the highest energy bin). We have fitted the spectrum with a model consistent with the positron flux measured by AMS-02 below 1\u00a0TeV and interpreted the\u00a0electron<\/span><\/span>+<\/span><\/span>positron<\/span><\/span><\/span><\/span><\/span><\/span><\/span>\u00a0spectrum with possible contributions from pulsars and nearby sources. Above 4.8\u00a0TeV, a possible contribution from known nearby supernova remnants, including Vela, is addressed by an event-by-event analysis providing a higher proton-rejection power than a purely statistical analysis.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"excerpt":{"rendered":"

Journal Title \/\u63b2\u8f09\u30b8\u30e3\u30fc\u30ca\u30eb\u540d Physical Review Letters Publication Year and Month \/\u63b2\u8f09\u5e74\u6708 November, 2023 Paper Title \/\u8ad6 […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[],"tags":[218,217],"class_list":["post-75650","post","type-post","status-publish","format-standard","hentry","tag-impact-en","tag-impact"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts\/75650","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/comments?post=75650"}],"version-history":[{"count":1,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts\/75650\/revisions"}],"predecessor-version":[{"id":75651,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/posts\/75650\/revisions\/75651"}],"wp:attachment":[{"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/media?parent=75650"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/categories?post=75650"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/research\/wp-json\/wp\/v2\/tags?post=75650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}