title: Measurement of the cosmic-ray antiproton spectrum at solar minimum with a long-duration balloon flight over antarctica.
abstract: The energy spectrum of cosmic-ray antiprotons (p's) from 0.17 to 3.5 GeV has been measured using 7886 p's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary p calculations. Cosmologically primary p's have been investigated by comparing measured and calculated p spectra. BESS-Polar II data show no evidence of primary p's from the evaporation of primordial black holes.
authors.affiliation: Kobe University, Kobe, Hyogo 657-8501, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Abe
authors.forename: H
authors.initials: H
authors.lastname: Fuke
authors.forename: S
authors.initials: S
authors.lastname: Haino
authors.forename: T
authors.initials: T
authors.lastname: Hams
authors.forename: M
authors.initials: M
authors.lastname: Hasegawa
authors.forename: A
authors.initials: A
authors.lastname: Horikoshi
authors.forename: K C
authors.initials: KC
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Kusumoto
authors.forename: M H
authors.initials: MH
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Makida
authors.forename: S
authors.initials: S
authors.lastname: Matsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Matsukawa
authors.forename: J W
authors.initials: JW
authors.lastname: Mitchell
authors.forename: J
authors.initials: J
authors.lastname: Nishimura
authors.forename: M
authors.initials: M
authors.lastname: Nozaki
authors.forename: R
authors.initials: R
authors.lastname: Orito
authors.forename: J F
authors.initials: JF
authors.lastname: Ormes
authors.forename: K
authors.initials: K
authors.lastname: Sakai
authors.forename: M
authors.initials: M
authors.lastname: Sasaki
authors.forename: E S
authors.initials: ES
authors.lastname: Seo
authors.forename: R
authors.initials: R
authors.lastname: Shinoda
authors.forename: R E
authors.initials: RE
authors.lastname: Streitmatter
authors.forename: J
authors.initials: J
authors.lastname: Suzuki
authors.forename: K
authors.initials: K
authors.lastname: Tanaka
authors.forename: N
authors.initials: N
authors.lastname: Thakur
authors.forename: T
authors.initials: T
authors.lastname: Yamagami
authors.forename: A
authors.initials: A
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
authors.forename: K
authors.initials: K
authors.lastname: Yoshimura