Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The structure of the X(3872) as explained by a Diffusion Monte Carlo
  calculation   Two decades after its unexpected discovery, the properties of the $X(3872)$
exotic resonance are still under intense scrutiny. In particular, there are
doubts about its nature as an ensemble of mesons or having any other internal
structure. We use a Diffusion Monte Carlo method to solve the many-body
Schr\"odinger equation that describes this state as a $c \bar c n \bar n$
($n=u$ or $d$ quark) system. This approach accounts for multi-particle
correlations in physical observables avoiding the usual quark-clustering
assumed in other theoretical techniques. The most general and accepted pairwise
Coulomb$\,+\,$linear-confining$\,+\,$hyperfine spin-spin interaction, with
parameters obtained by a simultaneous fit of around 100 masses of mesons and
baryons, is used. The $X(3872)$ contains light quarks whose masses are given by
the mechanism responsible of the dynamical breaking of chiral symmetry. The
same mechanisms gives rise to Goldstone-boson exchange interactions between
quarks that have been fixed in the last 10-20 years reproducing hadron,
hadron-hadron and multiquark phenomenology. It appears that a meson-meson
molecular configuration is preferred but, contrary to the usual assumption of
$D^0\bar{D}^{\ast0}$ molecule for the $X(3872)$, our formalism produces $\omega
J/\psi$ and $\rho J/\psi$ clusters as the most stable ones, which could explain
in a natural way all the observed features of the $X(3872)$.

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The categories of this paper are: supr-con
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom