title: Cosmic-ray positron energy spectrum measured by PAMELA.
abstract: Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24,500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.
authors.affiliation: Department of Physics, University of Florence, I-50019 Sesto Fiorentino, Florence, Italy and INFN, Sezione di Florence, I-50019 Sesto Fiorentino, Florence, Italy.
authors.forename: O
authors.initials: O
authors.lastname: Adriani
authors.forename: G C
authors.initials: GC
authors.lastname: Barbarino
authors.forename: G A
authors.initials: GA
authors.lastname: Bazilevskaya
authors.forename: R
authors.initials: R
authors.lastname: Bellotti
authors.forename: A
authors.initials: A
authors.lastname: Bianco
authors.forename: M
authors.initials: M
authors.lastname: Boezio
authors.forename: E A
authors.initials: EA
authors.lastname: Bogomolov
authors.forename: M
authors.initials: M
authors.lastname: Bongi
authors.forename: V
authors.initials: V
authors.lastname: Bonvicini
authors.forename: S
authors.initials: S
authors.lastname: Bottai
authors.forename: A
authors.initials: A
authors.lastname: Bruno
authors.forename: F
authors.initials: F
authors.lastname: Cafagna
authors.forename: D
authors.initials: D
authors.lastname: Campana
authors.forename: R
authors.initials: R
authors.lastname: Carbone
authors.forename: P
authors.initials: P
authors.lastname: Carlson
authors.forename: M
authors.initials: M
authors.lastname: Casolino
authors.forename: G
authors.initials: G
authors.lastname: Castellini
authors.forename: C
authors.initials: C
authors.lastname: De Donato
authors.forename: C
authors.initials: C
authors.lastname: De Santis
authors.forename: N
authors.initials: N
authors.lastname: De Simone
authors.forename: V
authors.initials: V
authors.lastname: Di Felice
authors.forename: V
authors.initials: V
authors.lastname: Formato
authors.forename: A M
authors.initials: AM
authors.lastname: Galper
authors.forename: A V
authors.initials: AV
authors.lastname: Karelin
authors.forename: S V
authors.initials: SV
authors.lastname: Koldashov
authors.forename: S A
authors.initials: SA
authors.lastname: Koldobskiy
authors.forename: S Y
authors.initials: SY
authors.lastname: Krutkov
authors.forename: A N
authors.initials: AN
authors.lastname: Kvashnin
authors.forename: A
authors.initials: A
authors.lastname: Leonov
authors.forename: V
authors.initials: V
authors.lastname: Malakhov
authors.forename: L
authors.initials: L
authors.lastname: Marcelli
authors.forename: M
authors.initials: M
authors.lastname: Martucci
authors.forename: A G
authors.initials: AG
authors.lastname: Mayorov
authors.forename: W
authors.initials: W
authors.lastname: Menn
authors.forename: M
authors.initials: M
authors.lastname: Mergé
authors.forename: V V
authors.initials: VV
authors.lastname: Mikhailov
authors.forename: E
authors.initials: E
authors.lastname: Mocchiutti
authors.forename: A
authors.initials: A
authors.lastname: Monaco
authors.forename: N
authors.initials: N
authors.lastname: Mori
authors.forename: R
authors.initials: R
authors.lastname: Munini
authors.forename: G
authors.initials: G
authors.lastname: Osteria
authors.forename: F
authors.initials: F
authors.lastname: Palma
authors.forename: P
authors.initials: P
authors.lastname: Papini
authors.forename: M
authors.initials: M
authors.lastname: Pearce
authors.forename: P
authors.initials: P
authors.lastname: Picozza
authors.forename: C
authors.initials: C
authors.lastname: Pizzolotto
authors.forename: M
authors.initials: M
authors.lastname: Ricci
authors.forename: S B
authors.initials: SB
authors.lastname: Ricciarini
authors.forename: L
authors.initials: L
authors.lastname: Rossetto
authors.forename: R
authors.initials: R
authors.lastname: Sarkar
authors.forename: V
authors.initials: V
authors.lastname: Scotti
authors.forename: M
authors.initials: M
authors.lastname: Simon
authors.forename: R
authors.initials: R
authors.lastname: Sparvoli
authors.forename: P
authors.initials: P
authors.lastname: Spillantini
authors.forename: S J
authors.initials: SJ
authors.lastname: Stochaj
authors.forename: J C
authors.initials: JC
authors.lastname: Stockton
authors.forename: Y I
authors.initials: YI
authors.lastname: Stozhkov
authors.forename: A
authors.initials: A
authors.lastname: Vacchi
authors.forename: E
authors.initials: E
authors.lastname: Vannuccini
authors.forename: G I
authors.initials: GI
authors.lastname: Vasilyev
authors.forename: S A
authors.initials: SA
authors.lastname: Voronov
authors.forename: Y T
authors.initials: YT
authors.lastname: Yurkin
authors.forename: G
authors.initials: G
authors.lastname: Zampa
authors.forename: N
authors.initials: N
authors.lastname: Zampa
authors.forename: V G
authors.initials: VG
authors.lastname: Zverev