Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Favoured $B_c$ Decay modes to search for a Majorana neutrino   Recently, the LHCb collaboration reported the observation of the decay mode
$B_{c}^{-}\rightarrow\overline{B}_{s}^{0}\pi^{-}$ with the largest exclusive
branching fraction amongst the known decay modes of all the $B$ mesons. Here we
propose a search for a few lepton-number violating decay modes of $B_c$ which
can only be induced by Majorana neutrinos. Distinguishing between Dirac and
Majorana nature of neutrinos is an outstanding problem and hence, all possible
searches for Majorana neutrinos need to be carried out. Since the lepton number
violating modes are expected to be rare, when using meson decay modes for these
searches one expects CKM favoured modes to be the preferred ones;
$B_{c}\rightarrow B_{s}$ is one such transition. With a resonance enhancement
of the Majorana neutrino mediating the
$B_{c}^{-}\rightarrow\overline{B}_{s}^{0}\ell_{1}{-}\ell_{2}^{-}\pi^{+}$ modes
one can hope to observe these rare modes, or, even their non-observation can be
used to obtain constraints on the mixing angles of the heavy Majorana singlet
with the light flavour neutrinos from upper limits of the branching fractions
which are tighter or compatible with results from earlier studies. Also, we
find that the relatively suppressed mode $B_{c}^{-}\rightarrow
J/\psi\ell_{1}^{-}\ell_{2}^{-}\pi^{+}$ can provide even tighter constraints on
$\mid V_{e N}\mid^2$, $\mid V_{\mu N}\mid^2$, $\mid V_{e N} V_{\mu N}\mid$, and
in a larger range of the heavy neutrino mass. Further, exclusion regions for
$\mid V_{e N} V_{\tau N}\mid$, $\mid V_{\mu N} V_{\tau N}\mid$ can also be
obtained for masses larger than those accessible in tau decays. Upper limits on
$\mathscr{B}\left(B_{c}^{-}\rightarrow\pi^{+}\ell_{1}^{-}\ell_{2}^{-}\right)$
can also result in stringent exclusion curves for all the mixing elements,
including that for $\mid V_{\tau N}\mid^2$ in a mass range where it is
unconstrained thus far.

30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
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The categories of this paper are: physics
32
The categories of this paper are: atom-ph