Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Tests of Lepton Flavour Universality with Semileptonic Decays at LHCb   The observable $\mathcal{R} \left( D^{(*)} \right) = \mathcal{B}\left(
B^{0}\to D^{(*)-} \tau^{+} \nu_{\tau} \right) / \mathcal{B}\left( B^{0}\to
D^{(*)-} \mu^{+} \nu_{\mu} \right)$ is a probe for Lepton Universality
violation, so it is sensitive to New Physics processes. The current combination
of the measurements of $\mathcal{R} \left( D^{(*)} \right)$ differs from
Standard Model predictions with a $4\sigma$ significance. A measurement of
$\mathcal{R} ( D^* )$ using three-prong $\tau$ decays has been performed at
LHCb, resulting in $\mathcal{R}(D^*) = 0.285 \pm 0.019 (\text{stat}) \pm
0.025(\text{syst}) \pm 0.014 (\text{ext})$. This value, combined with the LHCb
result obtained with $\tau \to \mu \nu_\tau \bar{\nu}_\mu$ decays, gives
${\mathcal{R}}(D^*) = 0.306 \pm 0.016 (\text{stat}) \pm 0.022 (\text{syst})$,
consistent with the world average and 2.1 standard deviations above the SM
prediction.

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The categories of this paper are: chem-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: cs
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The categories of this paper are: patt-sol
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The categories of this paper are: chao-dyn
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The categories of this paper are: astro-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin