\bottomheading{Pseudo scalar mediator, processes 803 and 823}
803~$ PS\to({\chi}(p_3)+\bar{\chi}(p_4)) +f(p_5)$ [Pseudo Scalar Mediator]  NLO  \\
823~$ PS\to({\chi}(p_3)+\bar{\chi}(p_4)) +\gamma(p_5) $[Pseudo Scalar Mediator]  NLO + F 

Processes 803 and 823 produce the 
mono-jet or mono-photon signature through the following pseudo-scalar operator, 
\begin{eqnarray}
\mathcal{O}_{PS}=\frac{m_q(\overline{\chi}\gamma_5\chi)(\overline{q}\gamma_5q)}{\Lambda^3}\label{eq:OPS}~.
\end{eqnarray}
These processes are available at NLO and include the usual treatment
of photons. See for instance the $V\gamma$ processes ($\sim$ 300) in
this manual for more details on photon setup in MCFM. As discussed
above the code will calculate left and right-handed helicity
amplitudes and build the pseudo scalar operators from $(L-R)$. By
default the code will enforce the right handed couplings to equal to
the negative of the left handed couplings, if this is not
already the case in {\tt dm\_parameters.DAT}. Therefore the user does
not have to change this file when switching between scalar and pseudo
scalar operators.  Processes 841 and 846 represent the production of
DM plus two jets or DM plus one jet and one photon and are available
at LO.  For these processes $\Delta$ is fixed from the value of {\tt
  [Yukawa Scalar Couplings] } if this is {\tt .true.} then
$\Delta=m_q/\Lambda$ else $\Delta=1$.