Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of the "$K^-pp$"-like structure in the $d(\pi^+, K^+)$
  reaction at 1.69 GeV/$c$   We have observed a "$K^-pp$"-like structure in the $d(\pi^+,K^+)$ reaction at
1.69 GeV/$c$. In this reaction $\Lambda(1405)$ hyperon resonance is expected to
be produced as a doorway to form the $K^-pp$ through the $\Lambda^*p\rightarrow
K^-pp$ process. However, most of the produced $\Lambda(1405)$'s would escape
from deuteron without secondary reactions. Therefore, coincidence of
high-momentum ($>$ 250~MeV/$c$) proton(s) in large emission angles
($39^\circ<\theta_{lab.}<122^\circ$) was requested to enhance the
signal-to-background ratio. A broad enhancement in the proton coincidence
spectra are observed around the missing-mass of 2.27 GeV/$c^2$, which
corresponds to the $K^-pp$ binding energy of 95 $^{+18}_{-17}$ (stat.)
$^{+30}_{-21}$ (syst.) MeV and the width of 162 $^{+87}_{-45}$ (stat.)
$^{+66}_{-78}$ (syst.) MeV.

36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol