Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Atmospheric Neutrino Oscillations, theta(13) and Neutrino Mass Hierarchy   We derive predictions for the Nadir angle (theta(n)) dependence of the ratio
N(mu)/N(e) of the rates of the mu-like and e-like multi-GeV events measured in
water-Cerenkov detectors in the case of 3-neutrino oscillations of the
atmospheric nu(e) (antinu(e)) and nu(mu) (antinu(mu)), driven by one neutrino
mass squared difference, |Delta m2(31)| ~ (2.5 - 3.0) x 10^(-3) eV^2 >> Delta
m2(21). This ratio is particularly sensitive to the Earth matter effects in the
atmospheric neutrino oscillations, and thus to the values of sin^2(theta(13))
and sin^2(theta(23)), theta(13) and theta(23) being the neutrino mixing angle
limited by the CHOOZ and Palo Verde experiments and that responsible for the
dominant atmospheric nu(mu) -> nu(tau) (antinu(mu) -> antinu(tau))
oscillations. It is also sensitive to the type of neutrino mass spectrum which
can be with normal (Delta m2(31) > 0) or with inverted (Delta m2(31) < 0)
hierarchy. We show that for sin^2(theta(13)) > 0.01, sin^2(theta(23)) > 0.5 and
at cos(theta(n)) > 0.4, the Earth matter effects modify substantially the
theta(n)-dependence of the ratio N(mu)/N(e) and in a way which cannot be
reproduced with sin^2(theta(13)) = 0 and a different value of sin^2(theta(23)).
For normal hierarchy the effects can be as large as ~ 25% for cos(theta(n)) ~
(0.5 - 0.8), can reach ~ 35% in the Earth core bin cos(theta(n)) ~ (0.84 -
1.0), and might be observable. They are typically by ~ 10% smaller in the
inverted hierarchy case. An observation of the Earth matter effects in the
Nadir angle distribution of the ratio N(mu)/N(e) would clearly indicate that
sin^2(theta(13)) > 0.01 and sin^2(theta(23)) > 0.50.

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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: cs
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph