CalcuLAtionS of Self Interaction Cross Sections
This code provides approximate analytial expressions for the self-scattering cross sections of dark matter particles interacting via a Yukawa potential both in the semi-classical regime (k / mphi > 1, where k is the dark matter momentum and mphi is the mediator mass) and in the quantum regime (1 > k / mphi). One can calculate the momentum transfer cross section and the viscosity cross section for distinguishable particles, and the spin-averaged viscosity cross section for identical particles. To obtain the velocity-averaged cross sections for a Maxwell-Boltzmann distribution, the code interpolates tabulated numerical results.
For details, see B. Colquhoun, S. Heeba, F. Kahlhoefer, L. Sagunski and S. Tulin, The Semi-Classical Regime for Dark Matter Self-Interactions, arXiv:2011.04679.
For the Hulthen approximation, used to calculate the S-wave scattering cross sections in the quantum regime, see S. Tulin, H. Yu and K. Zurek, Beyond Collisionless Dark Matter: Particle Physics Dynamics for Dark Matter Halo Structure, arXiv:1302.3898.
For example usage, see cross_sections.py.
The tabulated values are provided in the following format (following the notation from arXiv:2011.04679):
- Column 1: beta_0
- Column 2: kappa_0
- Column 3: m_phi^2/pi * sigma_X^Y, where
- X = T or V for distinguishable particles and X = even, odd, scalar, fermion or vector for identical particles
- Y = attractive, repulsive