High energy cosmic ray physics with underground muons in MACRO. II. Primary spectra and composition
- Dipartimento di Fisica dellUniversita di Bari and INFN, 70126 Bari (Italy)
- Dipartimento di Fisica dellUniversita di Bologna and INFN, 40126 Bologna (Italy)
- Physics Department, Boston University, Boston, Massachusetts 02215 (United States)
- California Institute of Technology, Pasadena, California 91125 (United States)
- Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104 (United States)
- Laboratori Nazionali di Frascati dellINFN, 00044 Frascati (Roma) (Italy)
- Laboratori Nazionali del Gran Sasso dellINFN, 67010 Assergi (LAquila) (Italy)
- Departments of Physics and Astronomy, Indiana University, Bloomington, Indiana 47405 (United States)
- Dipartimento di Fisica dellUniversita dellAquila and INFN, 67100 LAquila (Italy)
- Dipartimento di Fisica dellUniversita di Lecce and INFN, 73100 Lecce (Italy)
Multimuon data from the MACRO experiment at Gran Sasso have been analyzed using a new method, which allows one to estimate the primary cosmic ray fluxes. The estimated all-particle spectrum is higher and flatter than the one obtained from direct measurements but is consistent with EAS array measurements. The spectral indexes of the fitted energy spectrum are 2.56{plus_minus}0.05 for E{lt}500 TeV and 2.9{plus_minus}0.3 for E{gt}5000 TeV with a gradual change at intermediate energies. The average mass number shows little dependence on the primary energy below 1000 TeV, with a value of 10.1{plus_minus}2.5 at 100 TeV. At higher energies the best fit average mass shows a mild increase with energy, even though no definite conclusion can be reached taking into account errors. The fitted spectra cover a range from {approximately} 50 TeV up to several thousand TeV. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 628680
- Journal Information:
- Physical Review, D, Vol. 56, Issue 3; Other Information: PBD: Aug 1997
- Country of Publication:
- United States
- Language:
- English
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