Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: First Indication of Terrestrial Matter Effects on Solar Neutrino
  Oscillation   We report an indication that the elastic scattering rate of solar $^8$B
neutrinos with electrons in the Super-Kamiokande detector is larger when the
neutrinos pass through the Earth during nighttime. We determine the day/night
asymmetry, defined as the difference of the average day rate and average night
rate divided by the average of those two rates, to be
$(-3.2\pm1.1(\text{stat})\pm0.5(\text{syst}))\%$, which deviates from zero by
2.7 $\sigma$. Since the elastic scattering process is mostly sensitive to
electron-flavored solar neutrinos, a non-zero day/night asymmetry implies that
the flavor oscillations of solar neutrinos are affected by the presence of
matter within the neutrinos' flight path. Super-Kamiokande's day/night
asymmetry is consistent with neutrino oscillations for
$4\times10^{-5}$eV$^2\leq\Delta m^2_{21}\leq7\times10^{-5}$eV$^2$ and large
mixing values of $\theta_{12}$, at the $68\%$ C.L.

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The categories of this paper are: astro-ph
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The categories of this paper are: econ
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: patt-sol
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The categories of this paper are: math
0
The categories of this paper are: hep-ph