Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is there really a $W \to \tau\nu$ puzzle?   According to the Particle Data Group, the measurements of ${\cal B}(W^+ \to
\tau^+ \nu_\tau)$ and ${\cal B}(W^+ \to \ell^+ \nu_\ell)$ ($\ell = e,\mu$)
disagree with one another at the $2.3\sigma$ level. In this paper, we search
for a new-physics (NP) explanation of this $W \to \tau\nu$ puzzle. We consider
two NP scenarios: (i) the $W$ mixes with a $W'$ boson that couples
preferentially to the third generation, (ii) $\tau_{L,R}$ and $\nu_{\tau L}$
mix with isospin-triplet leptons. Unfortunately, once other experimental
constraints are taken into account, neither scenario can explain the above
experimental result. Our conclusion is that the $W \to \tau\nu$ puzzle is
almost certainly just a statistical fluctuation.

30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
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The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs