Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Probing the $L_\mu$-$L_\tau$ Gauge Boson at the MUonE Experiment   We discuss the prospects of probing the $L_\mu - L_\tau$ gauge boson at the
MUonE experiment. The $L_\mu - L_\tau$ gauge boson $Z^\prime$ with a mass of
$\lesssim 200$ MeV, which can explain the discrepancy between the measured
value of the muon $g-2$ and the value calculated in the Standard Model, can be
produced at the MUonE experiment through the process $\mu e \to \mu e
Z^\prime$. The $Z^\prime$ in the final state decays into a pair of neutrinos,
and therefore we cannot observe the decay of $Z^\prime$ directly. It is,
however, still possible to probe this signature by searching for events with a
large scattering angle of muon and a less energetic final-state electron. The
background events coming from the elastic scattering $\mu e \to \mu e$ as well
as radiative process $\mu e \to \mu e \gamma$ can be removed by the kinematical
cuts on the muon scattering angle and the electron energy, in addition to a
photon veto. The background events from the electroweak process $\mu e \to \mu
e \nu \bar{\nu}$ are negligible. With our selection criteria, the number of
signal events $\mu e \to \mu e Z^\prime$ is found to be as large as $\sim 10^3$
in the parameter region motivated by the muon $g-2$ discrepancy. It is,
therefore, quite feasible to probe the $L_\mu - L_\tau$ gauge boson at the
MUonE experiment -- without introducing additional devices -- and we strongly
recommend recording the events relevant to this $Z^\prime$ production process.

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The categories of this paper are: supr-con
2
The categories of this paper are: math
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The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: cond-mat
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: math-ph
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The categories of this paper are: funct-an