Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Scalar-tensor theories, trace anomalies and the QCD-frame   We consider the quantum effects of matter fields in scalar-tensor theories
and clarify the role of trace anomaly when switching between conformally
related `frames'. We exploit the property that the couplings between the scalar
and the gauge fields are not frame-invariant in order to define a `QCD-frame',
where the scalar is not coupled to the gluons. We show that this frame is a
natural generalization of the `Jordan frame' in the case of non-metric theories
and that it is particularly convenient for gravitational phenomenology: test
bodies have trajectories that are as close as possible to geodesics with
respect to such a metric and equivalence principle violations are directly
proportional to the scalar coupling parameters written in this frame. We show
how RG flow and decoupling work in metric and non-metric theories. RG-running
commutes with the operation of switching between frames at different scales.
When only matter loops are considered, our analysis confirms that metricity is
stable under radiative corrections and shows that approximate metricity is
natural in a technical sense.

34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex