title: First Mass-resolved Measurement of High-Energy Cosmic-Ray Antiprotons.
abstract: We report new results for the cosmic-ray antiproton-to-proton ratio from 3 to 50 GeV at the top of the atmosphere. These results represent the first measurements, on an event-by-event basis, of mass-resolved antiprotons above 18 GeV. The results were obtained with the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas-RICH (Ring-Imaging Cerenkov) counter and a silicon-tungsten imaging calorimeter. The RICH detector was the first ever flown that is capable of identifying charge-one particles at energies above 5 GeV. The spectrometer was flown on 1998 May 28-29 from Fort Sumner, New Mexico. The measured p&d1;/p ratio is in agreement with a pure secondary interstellar production.
authors.initials: D
authors.lastname: Bergström
authors.initials: M
authors.lastname: Boezio
authors.initials: P
authors.lastname: Carlson
authors.initials: T
authors.lastname: Francke
authors.initials: S
authors.lastname: Grinstein
authors.initials: F
authors.lastname: Khalchukov
authors.initials: M
authors.lastname: Suffert
authors.initials: M
authors.lastname: Hof
authors.initials: J
authors.lastname: Kremer
authors.initials: W
authors.lastname: Menn
authors.initials: M
authors.lastname: Simon
authors.initials: SA
authors.lastname: Stephens
authors.initials: ML
authors.lastname: Ambriola
authors.initials: R
authors.lastname: Bellotti
authors.initials: F
authors.lastname: Cafagna
authors.initials: F
authors.lastname: Ciacio
authors.initials: M
authors.lastname: Circella
authors.lastname: De Marzo C
authors.initials: N
authors.lastname: Finetti
authors.initials: P
authors.lastname: Papini
authors.initials: S
authors.lastname: Piccardi
authors.initials: P
authors.lastname: Spillantini
authors.initials: S
authors.lastname: Bartalucci
authors.initials: M
authors.lastname: Ricci
authors.initials: M
authors.lastname: Casolino
authors.lastname: De Pascale MP
authors.initials: A
authors.lastname: Morselli
authors.initials: P
authors.lastname: Picozza
authors.initials: R
authors.lastname: Sparvoli
authors.initials: V
authors.lastname: Bonvicini
authors.initials: P
authors.lastname: Schiavon
authors.initials: A
authors.lastname: Vacchi
authors.initials: N
authors.lastname: Zampa
authors.initials: JW
authors.lastname: Mitchell
authors.initials: JF
authors.lastname: Ormes
authors.initials: RE
authors.lastname: Streitmatter
authors.initials: U
authors.lastname: Bravar
authors.initials: SJ
authors.lastname: Stochaj