Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Azimuthal flow of decay photons in relativistic nuclear collisions   An overwhelming fraction of photons from relativistic heavy ion collisions
has its origin in the decay of $\pi^0$ and $\eta$ mesons. We calculate the
azimuthal asymmetry of the decay photons for several azimuthally asymmetric
pion distributions. We find that the $k_T$ dependence of the elliptic flow
parameter$v_2$ for the decay photons closely follows the elliptic flow
parameter $v_2^{\pi^0}$ evaluated at $p_T \approx k_T+\delta$, where
$\delta\approx$ 0.1 -- 0.2 GeV, for typical pion distributions measured in
nucleus-nucleus collisions at relativistic energies. Similar results are
obtained for photons from the 2-$\gamma$ decay of $\eta$ mesons. Assuming that
the flow of $\pi^0$ is similar to those for $\pi^+$ and $\pi^-$ for which
independent measurements would be generally available, this ansatz can help in
identifying additional sources for photons. Taken along with quark number
scaling suggested by the recombination model, it may help to estimate $v_2$ of
the parton distributions in terms of azimuthal asymmetry of the decay photons
at large $k_T$.

23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph