Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for Antimatter in Space with the Alpha Magnetic Spectrometer   The Alpha Magnetic Spectrometer (AMS) is a state of the art particle physics
experiment for the extraterrestrial study of antimatter, matter and missing
matter. AMS successfully completed the precursor STS91 Discovery flight (June
2nd-12th, 1998), completing 152 orbits at 52 degrees of latitude and about 400
km of height, collecting more than 100 million CR events. In this paper we
report on the first flight experience and we present preliminary results on the
search for nuclear antimatter. No antimatter nuclei with Z>=2 were detected. We
obtain a model dependent upper limit on the anti-He /He flux <1.14 10^^-6 In
the rigidity region between 1.6 to 20 GV we obtain a model independent,
conservative upper limit on anti-He /He flux <1.7 10^^-6 and <2.8 10^^-5 for
Z>2, improving the results of previous published searches performed with
stratospheric balloons.

1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc