Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological Constraint on Vector Mediator of Neutrino-Electron
  Interaction in light of XENON1T Excess   Recently, the XENON1T collaboration reported an excess in the electron recoil
energy spectrum. One of the simplest new physics interpretation is a new
neutrino-electron interaction mediated by a light vector particle. However, for
the parameter region favored by this excess, the constraints from the stellar
cooling are severe. Still, there are astrophysical uncertainties on those
constraints. In this paper, we discuss the constraint on the light mediator
from the effective number of neutrino Neff in the CMB era, which provides an
independent constraint. We show that Neff is significantly enhanced and exceeds
the current constraint in the parameter region favored for the XENON1T excess.
As a result, the interpretation by a light mediator heavier than about 1 eV is
excluded by the Neff constraint.

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The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th