Antihelium in cosmic rays: A new upper limit and its significance

J. F. Ormes, A. A. Moiseev, T. Saeki, K. Anraku, S. Orito, R. L. Golden, M. Imori, S. Inaba, B. L. Klmbell, N. Klmura, Y. Makida, H. Matsumoto, H. Matsunaga, J. W. Mltchell, M. Motoki, J. Nishimura, M. Nozaki, R. E. Streitmatter, J. Suzuki, K. TanakaI. Ueda, N. Yajima, T. Yamagami, A. Yamamoto, T. Yoshida, Koji Yoshimura

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

We have searched for antihelium in the galactic cosmic rays using data obtained on the flight of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) launched from Lynn Lake, Manitoba, in northern Canada on 1995 July 25. The balloon reached an altitude of 36.5 km with a residual overburden of 5 g cm-2. The total observation time was 12.2 hr with a live-time fraction of 0.61. No antihelium was observed after selections based on dE/dx and event quality cuts at rigidities between 1.6 and 16 GV/c; we infer that 536,420 helium nuclei survived the same cuts. This result leads to an upper limit to the He/He abundance ratio of 8.1 × 10-6 (95% confidence level), a factor of 2.7 over the lowest previous limit. Because this limit is for the first time at the level where predicted limits become astrophysically interesting (Ahlen et al.), we have reexamined the transport of cosmic rays in intergalactic space. We show that little can be learned about distant (>10 Mpc) domains of antimatter from a null result.

Original languageEnglish
JournalAstrophysical Journal
Volume482
Issue number2 PART II
Publication statusPublished - 1997
Externally publishedYes

Fingerprint

cosmic ray
cosmic rays
balloons
rigidity
overburden
helium
spectrometer
flight
Manitoba
antimatter
lake
Canada
lakes
confidence
experiment
spectrometers
nuclei

Keywords

  • Balloons
  • Cosmic rays
  • Magnetic fields

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Space and Planetary Science

Cite this

Ormes, J. F., Moiseev, A. A., Saeki, T., Anraku, K., Orito, S., Golden, R. L., ... Yoshimura, K. (1997). Antihelium in cosmic rays: A new upper limit and its significance. Astrophysical Journal, 482(2 PART II).

Antihelium in cosmic rays : A new upper limit and its significance. / Ormes, J. F.; Moiseev, A. A.; Saeki, T.; Anraku, K.; Orito, S.; Golden, R. L.; Imori, M.; Inaba, S.; Klmbell, B. L.; Klmura, N.; Makida, Y.; Matsumoto, H.; Matsunaga, H.; Mltchell, J. W.; Motoki, M.; Nishimura, J.; Nozaki, M.; Streitmatter, R. E.; Suzuki, J.; Tanaka, K.; Ueda, I.; Yajima, N.; Yamagami, T.; Yamamoto, A.; Yoshida, T.; Yoshimura, Koji.

In: Astrophysical Journal, Vol. 482, No. 2 PART II, 1997.

Research output: Contribution to journalArticle

Ormes, JF, Moiseev, AA, Saeki, T, Anraku, K, Orito, S, Golden, RL, Imori, M, Inaba, S, Klmbell, BL, Klmura, N, Makida, Y, Matsumoto, H, Matsunaga, H, Mltchell, JW, Motoki, M, Nishimura, J, Nozaki, M, Streitmatter, RE, Suzuki, J, Tanaka, K, Ueda, I, Yajima, N, Yamagami, T, Yamamoto, A, Yoshida, T & Yoshimura, K 1997, 'Antihelium in cosmic rays: A new upper limit and its significance', Astrophysical Journal, vol. 482, no. 2 PART II.
Ormes JF, Moiseev AA, Saeki T, Anraku K, Orito S, Golden RL et al. Antihelium in cosmic rays: A new upper limit and its significance. Astrophysical Journal. 1997;482(2 PART II).
Ormes, J. F. ; Moiseev, A. A. ; Saeki, T. ; Anraku, K. ; Orito, S. ; Golden, R. L. ; Imori, M. ; Inaba, S. ; Klmbell, B. L. ; Klmura, N. ; Makida, Y. ; Matsumoto, H. ; Matsunaga, H. ; Mltchell, J. W. ; Motoki, M. ; Nishimura, J. ; Nozaki, M. ; Streitmatter, R. E. ; Suzuki, J. ; Tanaka, K. ; Ueda, I. ; Yajima, N. ; Yamagami, T. ; Yamamoto, A. ; Yoshida, T. ; Yoshimura, Koji. / Antihelium in cosmic rays : A new upper limit and its significance. In: Astrophysical Journal. 1997 ; Vol. 482, No. 2 PART II.
@article{3f600e898e2e48f48ceb655d1e5b008f,
title = "Antihelium in cosmic rays: A new upper limit and its significance",
abstract = "We have searched for antihelium in the galactic cosmic rays using data obtained on the flight of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) launched from Lynn Lake, Manitoba, in northern Canada on 1995 July 25. The balloon reached an altitude of 36.5 km with a residual overburden of 5 g cm-2. The total observation time was 12.2 hr with a live-time fraction of 0.61. No antihelium was observed after selections based on dE/dx and event quality cuts at rigidities between 1.6 and 16 GV/c; we infer that 536,420 helium nuclei survived the same cuts. This result leads to an upper limit to the He/He abundance ratio of 8.1 × 10-6 (95{\%} confidence level), a factor of 2.7 over the lowest previous limit. Because this limit is for the first time at the level where predicted limits become astrophysically interesting (Ahlen et al.), we have reexamined the transport of cosmic rays in intergalactic space. We show that little can be learned about distant (>10 Mpc) domains of antimatter from a null result.",
keywords = "Balloons, Cosmic rays, Magnetic fields",
author = "Ormes, {J. F.} and Moiseev, {A. A.} and T. Saeki and K. Anraku and S. Orito and Golden, {R. L.} and M. Imori and S. Inaba and Klmbell, {B. L.} and N. Klmura and Y. Makida and H. Matsumoto and H. Matsunaga and Mltchell, {J. W.} and M. Motoki and J. Nishimura and M. Nozaki and Streitmatter, {R. E.} and J. Suzuki and K. Tanaka and I. Ueda and N. Yajima and T. Yamagami and A. Yamamoto and T. Yoshida and Koji Yoshimura",
year = "1997",
language = "English",
volume = "482",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2 PART II",

}

TY - JOUR

T1 - Antihelium in cosmic rays

T2 - A new upper limit and its significance

AU - Ormes, J. F.

AU - Moiseev, A. A.

AU - Saeki, T.

AU - Anraku, K.

AU - Orito, S.

AU - Golden, R. L.

AU - Imori, M.

AU - Inaba, S.

AU - Klmbell, B. L.

AU - Klmura, N.

AU - Makida, Y.

AU - Matsumoto, H.

AU - Matsunaga, H.

AU - Mltchell, J. W.

AU - Motoki, M.

AU - Nishimura, J.

AU - Nozaki, M.

AU - Streitmatter, R. E.

AU - Suzuki, J.

AU - Tanaka, K.

AU - Ueda, I.

AU - Yajima, N.

AU - Yamagami, T.

AU - Yamamoto, A.

AU - Yoshida, T.

AU - Yoshimura, Koji

PY - 1997

Y1 - 1997

N2 - We have searched for antihelium in the galactic cosmic rays using data obtained on the flight of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) launched from Lynn Lake, Manitoba, in northern Canada on 1995 July 25. The balloon reached an altitude of 36.5 km with a residual overburden of 5 g cm-2. The total observation time was 12.2 hr with a live-time fraction of 0.61. No antihelium was observed after selections based on dE/dx and event quality cuts at rigidities between 1.6 and 16 GV/c; we infer that 536,420 helium nuclei survived the same cuts. This result leads to an upper limit to the He/He abundance ratio of 8.1 × 10-6 (95% confidence level), a factor of 2.7 over the lowest previous limit. Because this limit is for the first time at the level where predicted limits become astrophysically interesting (Ahlen et al.), we have reexamined the transport of cosmic rays in intergalactic space. We show that little can be learned about distant (>10 Mpc) domains of antimatter from a null result.

AB - We have searched for antihelium in the galactic cosmic rays using data obtained on the flight of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) launched from Lynn Lake, Manitoba, in northern Canada on 1995 July 25. The balloon reached an altitude of 36.5 km with a residual overburden of 5 g cm-2. The total observation time was 12.2 hr with a live-time fraction of 0.61. No antihelium was observed after selections based on dE/dx and event quality cuts at rigidities between 1.6 and 16 GV/c; we infer that 536,420 helium nuclei survived the same cuts. This result leads to an upper limit to the He/He abundance ratio of 8.1 × 10-6 (95% confidence level), a factor of 2.7 over the lowest previous limit. Because this limit is for the first time at the level where predicted limits become astrophysically interesting (Ahlen et al.), we have reexamined the transport of cosmic rays in intergalactic space. We show that little can be learned about distant (>10 Mpc) domains of antimatter from a null result.

KW - Balloons

KW - Cosmic rays

KW - Magnetic fields

UR - http://www.scopus.com/inward/record.url?scp=21744459865&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=21744459865&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:21744459865

VL - 482

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2 PART II

ER -