Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On $D\to X_u l^+ l^-$ within the Standard Model and Frameworks like the
  Littlest Higgs Model with T Parity   The $D\to X_u l^+ l^-$ transitions -- branching ratios, forward-backward
asymmetry $A^c_{FB}$, the CP asymmetry $A^c_{CP}$ and the CP asymmetry in the
forward-backward asymmetry $A^{CP}_{FB}$ -- have two sources: for $D^{\pm}$
they represent a pure $\Delta C=1$ & $\Delta Q=0$ current interaction whereas
neutral $D$ mesons can also communicate via their anti-hadron. Standard Model
(SM) contributions to BR$(D\to X_u l^+ l^-)$ come primarily from long distance
dynamics, which overshadow short distance contributions by several orders of
magnitude; still they fall much below the present upper experimental bounds.
Even the SM contributions to $A^c_{FB}$, $A^c_{CP}$ and $A^{CP}_{FB}$ are tiny,
quite unlike in beauty hadrons. The branching ratios are hardly dented by
contributions from the Littlest Higgs Models with T parity (LHT) even in the
short distance regime, let alone in the SM long distances dynamics. Yet the
asymmetries $A^c_{FB}$, $A^c_{CP}$ and $A^{CP}_{FB}$ in these New Physics
models can be enhanced over SM predictions, as they arise purely from short
distance dynamics; this can occur in particular for $A^c_{FB}$ and
$A^{CP}_{FB}$ which get enhanced by orders of magnitudes. Even such
enhancements hardly reach absolute sizes for observable experimental effects
for $A^c_{FB}$ and $A^c_{CP}$. However LHT contributions to $A^{CP}_{FB}$ could
be measured in experiments like the LHCb and the SuperB Collaboration. These
results lead us to draw further conclusions on FCNCs within LHT-like models
through some simple scaling arguments that encapsulate the essence of flavour
dynamics in and beyond the Standard Model.

4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol