Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Introduction to Charged Lepton Flavour Violation   Neutrino masses are evidence of lepton flavour violation, but no violation in
the interactions among the charged leptons has been observed yet. Many models
of Physics Beyond the Standard Model (BSM) predict Charged Lepton Flavour
Violation (CLFV) in a wide spectrum of processes with rates in reach of
upcoming experiments. The experimental searches that provide the current best
limits on the CLFV searches are reviewed, with a particular emphasis on the
muon-based experiments that give the most stringent constraints on BSM
parameter space. The next generation of muon-based experiments (MEG-II, Mu2e,
COMET, Mu3e) aim to reach improvements by many orders of magnitude w.r.t. the
current best limits, thanks to several technological advancements. We review
popular heavy BSM theories, and we present state-of-the-art calculations of the
predicted CLFV branching ratios, focusing on the more sensitive $\mu\to e$
sector.

25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg