Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: D* polarization as a probe to discriminate new physics in B --> D* tau
  nubar   The confirmation of excess in $R_{D^*}$ at the LHCb is an indication of
lepton flavor non-universality. Various different new physics operators and
their coupling strengths, which provide a good fit to $R_D$, $R_{D^*}$ and
$q^2$ spectra, were identfied previously. In this work, we try to find angular
observables in $\bar{B} \to D^* \tau \bar{\nu}$ which enable us to distinguish
between these new physics operators. We find that the $D^*$ polarization
fraction $f_L(q^2)$ is a good discriminant of scalar and tensor new physics
operators. The change in $\langle f_L(q^2) \rangle$, induced by scalar and
tensor operators, is about three times larger than the expected uncertainty in
the upcoming Belle measurement.

25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
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The categories of this paper are: physics
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
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The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
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The categories of this paper are: nlin
10
The categories of this paper are: q-bio
2
The categories of this paper are: math