Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Constraints on the electron-to-proton mass ratio variation at the epoch
  of reionization   Far infrared fine-structure transitions of CI and CII and rotational
transitions of CO are used to probe hypothetical variations of the
electron-to-proton mass ratio mu = m_e/m_p at the epoch of reionization (z >
6). A constraint on Delta mu/mu = (mu_obs - mu_lab)/mu_lab = (0.7 +/-
1.2)x10^-5 (1sigma) obtained at <z> = 6.31 is the most stringent up-to-date
limit on the variation of mu at such high redshift. For all available estimates
of Delta mu/mu ranging between z = 0 and z = 1100, - the epoch of
recombination, - a regression curve Delta mu/mu = k_mu (1+z)^p, with k_mu =
(1.6 +/- 0.3) x10^-8 and p = 2.00 +/- 0.03, is deduced. If confirmed, this
would imply a dynamical nature of dark matter/dark energy.

11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol