Cosmic ray positrons at high energies: A new measurement.
نویسندگان
چکیده
We present a new measurement of the cosmic-ray positron fraction e + =(e + + e) obtained from the rst balloon ight of the High Energy Antimatter Telescope (HEAT). Using a magnet spectrometer combined with a transition radiation detector, an electromagnetic calorimeter, and time-of-ight counters we have achieved a high degree of background rejection. Our results do not indicate a major contribution to the positron ux from primary sources. In particular, we see no evidence for the signiicant rise in the positron
منابع مشابه
Og 7 . 1 . 3 Cosmic - Ray Positrons : Are There Primary Sources ?
The HEAT instrument has detected cosmic-ray electrons and positrons in two balloon ights, at energies between 1 and 50 GeV. The combined data set indicates that the positron fraction does not increase with energy above 10 GeV. However, our results suggest a slight overabundance of positrons at all energies compared with published predictions from secondary production sources, and possibly the h...
متن کاملPossible Interpretations of the High Energy Cosmic Ray Electron Spectrum measured with the Fermi Space Telescope
The Fermi Large Area Telescope has provided the measurement of the high energy (20 GeV to 1 TeV) cosmic ray electrons and positrons spectrum with unprecedented accuracy. This measurement represents a unique probe for studying the origin and diffusive propagation of cosmic rays as well as for looking for possible evidences of Dark Matter. In this contribution we focus mainly on astrophysical sou...
متن کاملPositron Annihilations at the Galactic Center: Generating More Questions Than Answers
The bulge of our Galaxy is illuminated by the 0.511 MeV gamma-ray line flux from annihilations of nonrelativistic positrons. The emission is strongly concentrated at the Galactic Center (GC), in contrast to gamma-ray maps tracing nucleosynthesis (e.g., the 1.809 MeV line from decaying Al) or cosmic ray processes (e.g., the 1–30 MeV continuum), which reveal a bright disk with a much less promine...
متن کاملLorentz Violation and Ultrahigh-Energy Photons
The propagation of photons, electrons and positrons at ultra-high energies above ∼ 10 eV can be changed considerably if the dispersion relations of these particles are modified by terms suppressed by powers of the Planck scale. We recently pointed out that the current non-observation of photons in the ultra-high energy cosmic ray flux at such energies can put strong constraints on such modified...
متن کاملObservation of an anomalous positron abundance in the cosmic radiation
Positrons are known to be produced in interactions between cosmic-ray nuclei and interstellar matter (“secondary production”). Positrons may, however, also be created by dark matter particle annihilations in the galactic halo or in the magnetospheres of near-by pulsars. The nature of dark matter is one of the most prominent open questions in science today. An observation of positrons from pulsa...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Physical review letters
دوره 75 3 شماره
صفحات -
تاریخ انتشار 1995