OBSERVATIONS OF HIGH-ENERGY COSMIC-RAY ELECTRONS FROM 30 GeV TO 3 TeV WITH EMULSION CHAMBERS

Abstract

We have performed a series of cosmic-ray electron observations using the balloon-borne emulsion chambers since 1968. While we previously reported the results from subsets of the exposures, the final results of the total exposures up to 2001 are presented here. Our successive experiments have yielded the total exposure of 8.19 m 2 sr day at the altitudes of 4.0 − 9.4 g cm −2 . The performance of the emulsion chambers was examined by accelerator beam tests and Monte-Carlo simulations, and the on-board calibrations were carried out by using the flight data. In this work we present the cosmic-ray electron spectrum in the energy range from 30 GeV to 3 TeV at the top of the atmosphere, which is well represented by a power-law function with an index of −3.28±0.10. The observed data can be also interpreted in terms of diffusive propagation models. The evidence of cosmic-ray electrons up to 3 TeV suggests the existence of cosmicray electron sources at distances within ∼ 1 kpc and times within ∼1×10 5 yr ago.Subject headings: cosmic rays: electrons, origin -balloons -supernova remnants 1 In this paper, the term "electrons" is used for the sum of particles regardless of charge. When we must identify the charge, we will use the terms "negative electrons" or "positrons".

Detecting and studying high-energy collider neutrinos with FASER at the LHC

“…The energy resolution of such an algorithm is estimated to be σ E = 50%/ √ E for E in GeV [104], implying an energy resolution of 25% for E = 4 GeV, and much better for higher energies. Another study with a similar detector technology reported energy resolutions below 15% for 50 and 200 GeV electron data [105]. However, in the case of FASER, a large number of low-energy background electron tracks produced by high-energy muons would limit the energy resolution.…”

A database of charged cosmic rays

“…- Fanselow et al (1969); Fanselow (1968) -Balloon (1965,1966,1968 - ( ) -Balloon (1965( ,1966( ,1968( ,1969 - Nishimura et al (1980Nishimura et al ( , 1985; Kobayashi (1999);Nishimura et al (2001); Kobayashi et al (2012) -Balloon (1968-1975,1979,1982,1984 -Balloon (1968/06+1968/07): Fulks (1975);Hovestadt et al (1971);Schmidt (1972) -Balloon (1969/06+1969/07): Fulks (1975Hovestadt et al (1971);Schmidt (1972) -Balloon (1970/06+1970/07): Fulks (1975Hovestadt et al (1971);Schmidt (1972) -Balloon (1971/06+1971/07): Fulks (1975Hovestadt et al (1971) -Balloon (1972/07): Fulks (1975Hovestadt et al (1971) -Balloon (1973 : Caldwell et al (1975) -Balloon (1974 : Caldwell et al (1977) -Balloon (1975 : Caldwell et al (1977) -Balloon (1977/07): Evenson et al (1979) -Balloon (1979/0...…”

The electron plus positron spectrum from annihilation of Kaluza–Klein dark matter in the Galaxy

“…5. One can see the observed data can be fit well by adding the LKP flux with an appropriate boost factor, and the Ackermann2010 [32] Adriani2011 [33] Kobayashi2012 [34] Aguilar2014 [15] Secondary [29] be consistent with the positron fraction may be larger than the upper limit on B f to be consistent with the electron plus positron spectrum. Although we can fit to the positron fraction and the electron plus positron spectrum separately by adding LKP contribution, the required boost factors differ significantly and it is difficult to explain both the electron plus positron spectrum and the positron fraction at the same time, if we only take account of observational data obtained by AMS-02.…”

“…Thick solid lines are the spectral fits to the AMS-02 data with upper-limit boost factor, B f = 80, 240, 465 for m B (1) = 500, 1000, 1500 GeV, respectively. Also shown are the recent observational data,15,[32][33][34] and an adjusted (factor C = 1.2 is multiplied) prediction spectrum by the cosmic-ray secondary calculation (thin dotted line). The value of boost factor assuming Isothermal (NFW) halo model and each propagation model with the best fit (B), lower (L) and upper (U) limit to AMS02 obeservational data (Positron Fraction).…”