due to spherical symmetry in momentum space, and $\hat \kappa_2$ is just a $2\times2$ matrix involving only terms containing $E$ and $Q$. In case correlations between particle number and conserved momenta are vanishing, i.e. $\kappa_2^{N_{4\pi},p_x} = 0$, or $\kappa_2^{N_{\Omega},p_x} = 0$, then, similarly to Eq.(\[normdet\]), the determinant of $\kappa_2$ factorizes into a product of correlation terms $(\kappa_2^{p_x,p_x})^3$ and the determinant of a $3\times3$ sub-matrix involving only terms containing $E$, $Q$, and $N$. Hence in taking the ratio Eq.(\[SimpleOmega\]) one notes, that in this case momentum conservation will not affect multiplicity fluctuations in the large volume limit [@clt]. In this work, however we do not necessarily find $ \kappa_2^{N_{\Omega},p_x} = 0 $, as we only integrate over a limited segment $\Omega$ of momentum space, and taking momentum conservation into account may affect the result.

Finally it should be stressed that this procedure can be easily generalized to account for Bose or Fermi statistics. Also phenomenological phase space suppression (enhancement) factors $\gamma_q$ [@gammaQfirst] or $\gamma_s$ [@gammaSfirst] could be straightforwardly included. However, without proper implementation of the effect of additional correlations due to resonance decay and collective motion, i.e. flow, it seems of little value to do too strict calculations for experimentally measurable 