Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A new $B$-flavour anomaly in $B_{d,s}\to K^{*0}\bar{K}^{*0}$: anatomy
  and interpretation   In the context of the recently measured non-leptonic decays $B_{d}\to
K^{*0}\bar{K}^{*0}$ and $B_{s}\to K^{*0}\bar{K}^{*0}$ we analyse the anatomy of
the $L_{VV}$ observable that compares the longitudinal components of $B_s \to
VV$ and $B_d \to VV$ decays. This observable is cleaner than the longitudinal
polarisation fraction as it is afflicted only at subleading order in a $1/m_b$
expansion by the theoretical uncertainties arising in the transverse components
entering the polarisation fraction. Focusing on the particular case of
$B_{d}\to K^{*0}\bar{K}^{*0}$ and $B_{s}\to K^{*0}\bar{K}^{*0}$, we discuss the
main sources of hadronic uncertainty in the SM. We find for the SM prediction
$L_{K^*\bar{K}^*}=19.5^{+9.3}_{-6.8}$, which implies a $2.6\sigma$ tension with
respect to the most recent data, pointing to a deficit in the $b \to s$
transition of the non-leptonic decay versus the corresponding $b \to d$
transition. We discuss possible New Physics explanations for this deviation,
first at the level of the Weak Effective Theory and we identify that the two
Wilson coefficients ${\cal C}_{4}$ and ${\cal C}_{8g}$ can play a central role
in explaining this anomaly. Finally, we briefly explore two different
simplified New Physics models which can explain the anomaly through a
contribution either in ${\cal C}_4$ (Kaluza-Klein gluon) or in ${\cal C}_{8g}$,
with a significant amount of fine tuning, but possible connections to the $b
\to s \ell \ell$ anomalies.

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The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
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The categories of this paper are: q-fin
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The categories of this paper are: math
33
The categories of this paper are: plasm-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: patt-sol
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: physics
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat