helicitydecay

class HelicityAmplitudeGenerator(top_node_no_dynamics=True, name_generator=<expertsystem.amplitude.helicitydecay.HelicityAmplitudeNameGenerator object>)

Bases: expertsystem.amplitude.abstractgenerator.AbstractAmplitudeGenerator

fix_parameters_unambiguously()

Fix parameters, so that the total amplitude is unambiguous, with regard to the fit parameters. In other words: all fit parameters per graph, except one, will all be fixed. It’s fine if they are all already fixed.

generate(graphs)

generate_amplitude_info(graph_groups)

generate_partial_decay(graph, node_id)

generate_sequential_decay(graph)

get_fit_parameters()

write_to_file(filename)

Return type

None

class HelicityAmplitudeNameGenerator(use_parity_conservation=False)

Bases: expertsystem.amplitude.abstractgenerator.AbstractAmplitudeNameGenerator

generate_amplitude_coefficient_infos(graph)

Generates coefficient info for a sequential amplitude graph.

Generally, each partial amplitude of a sequential amplitude graph should check itself if it or a parity partner is already defined. If so a coupled coefficient is introduced.

generate_unique_amplitude_name(graph, node_id=None)

Generates a unique name for the amplitude corresponding to the given StateTransitionGraph. If node_id is given, it generates a unique name for the partial amplitude corresponding to the interaction node of the given StateTransitionGraph.

determine_attached_final_state(graph, edge_id)

Determines all final state particles of a graph, which are attached downward (forward in time) for a given edge (resembling the root)

Parameters

• graph (StateTransitionGraph) –

• edge_id (int) – id of the edge, which is taken as the root

Returns

list of final state edge ids ([int])

determine_attached_final_state_string(graph, edge_id)

generate_kinematics(graphs)

generate_particle_list(graphs)

generate_particles_string(name_hel_list, use_helicity=True, make_parity_partner=False)

get_graph_group_unique_label(graph_group)

get_helicity_from_edge_props(edge_props)

get_parent_recoil_edge(graph, edge_id)

Determines the id of the recoil edge of the parent edge for the specified edge of a graph.

Parameters

• graph (StateTransitionGraph) –

• edge_id (int) – id of the edge, for which the parents recoil partner is determined

Returns

parent recoil edge id (int)

get_prefactor(graph)

calculates the product of all prefactors defined in this graph as a double

get_recoil_edge(graph, edge_id)

Determines the id of the recoil edge for the specified edge of a graph.

Parameters

• graph (StateTransitionGraph) –

• edge_id (int) – id of the edge, for which the recoil partner is determined

Returns

recoil edge id (int)

group_graphs_same_initial_and_final(graphs)

Each graph corresponds to a specific state transition amplitude. This function groups together graphs, which have the same initial and final state (including spin). This is needed to determine the coherency of the individual amplitude parts.

Parameters

graphs ([StateTransitionGraph]) –

Returns

graph groups ([[StateTransitionGraph]])

remove_spin_projection(edge_props)