Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $CP$ asymmetry in the angular distribution of $\tau\to K_S\pi\nu_\tau$
  decays   In this work, we study the $CP$ asymmetry in the angular distribution of
$\tau\to K_S\pi\nu_\tau$ decays, taking into account the known $CP$ violation
in $K^0-\bar{K}^0$ mixing. It is pointed out for the first time that, once the
well-measured $CP$ violation in the neutral kaon system is invoked, a non-zero
$CP$ asymmetry would appear in the angular observable of the decays considered,
even within the Standard Model. By employing the reciprocal basis, which is
most convenient when a $K_{S(L)}$ is involved in the final state, the
$CP$-violating angular observable is derived to be two times the product of the
time-dependent $CP$ asymmetry in $K\to \pi^+\pi^-$ and the mean value of the
angular distribution in $\tau^\pm\to
K^0(\bar{K}^0)\pi^\pm\bar{\nu}_\tau(\nu_\tau)$ decays. Compared with the Belle
results measured in four different bins of the $K\pi$ invariant mass, our
predictions lie within the margins of these measurements, except for a
$1.7~\sigma$ deviation for the lowest mass bin. While being below the current
Belle detection sensitivity that is of $\mathcal{O}(10^{-3})$, our predictions
are expected to be detectable at the Belle II experiment, where $\sqrt{70}$
times more sensitive results will be obtained with a $50~\text{ab}^{-1}$ data
sample.

7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph