Topology

class madspace.Topology(self: madspace._madspace_py.Topology, diagram: madspace._madspace_py.Diagram)

Bases: pybind11_object

One integration channel derived from a Diagram.

Splits the diagram into its t-channel momentum transfers (an ordered list of propagators) and its s-channel Topology::Decay tree, and records the order in which their invariants are sampled. Topology::topologies() enumerates the sub-channels of a diagram, one per set of propagators that can be simultaneously on shell (Sec. 2.2.7 of [1]). The constructor builds the single canonical channel. All particle indices are 0-based, with the two beams at 0 and 1, or the single decaying particle at 0.

References

Build the single canonical channel of a diagram.

Parameters:

diagram – The diagram to decompose.

property decay_integration_order

Sampling order of the s-channel invariants.

property decays

The s-channel decay-tree nodes.

property incoming_masses

Masses of the incoming particles.

property outgoing_indices

Diagram indices of the outgoing particles, in decay-tree order.

property outgoing_masses

Masses of the outgoing particles.

propagator_momentum_terms(self: madspace._madspace_py.Topology, only_decays: bool = False) → list[tuple[list[int], float, float]]

For each propagator, the outgoing momenta summed to form it and the energy window (indices, e_min, e_max).

Parameters:

only_decays – Restrict the result to the s-channel decay nodes.

property t_integration_order

Sampling order of the t-channel propagators.

property t_propagator_count

Number of space-like momentum transfers.

property t_propagator_masses

Masses of the t-channel propagators.

property t_propagator_widths

Widths of the t-channel propagators.

static topologies(diagram: madspace._madspace_py.Diagram) → list[madspace._madspace_py.Topology]

Enumerate the sub-channels of a diagram, one per on-shell configuration.

Parameters:

diagram – The diagram to decompose.