reaction¶

import expertsystem.reaction

Definition and solving of particle reaction problems.

This is the core component of the expertsystem: it defines the StateTransitionGraph data structure that represents a specific particle reaction. The solving submodule is responsible for finding solutions for particle reaction problems.

class ExecutionInfo(not_executed_node_rules: Dict[int, Set[str]] = NOTHING, violated_node_rules: Dict[int, Set[str]] = NOTHING, not_executed_edge_rules: Dict[int, Set[str]] = NOTHING, violated_edge_rules: Dict[int, Set[str]] = NOTHING)[source]¶

Bases: object

__eq__(other)¶: Method generated by attrs for class ExecutionInfo.

clear() → None [source]¶

extend(other_result: expertsystem.reaction.ExecutionInfo, intersect_violations: bool = False) → None [source]¶

not_executed_edge_rules: Dict[int, Set[str]]¶

not_executed_node_rules: Dict[int, Set[str]]¶

violated_edge_rules: Dict[int, Set[str]]¶

violated_node_rules: Dict[int, Set[str]]¶

class ProblemSet(topology: expertsystem.reaction.topology.Topology, initial_facts: expertsystem.reaction.combinatorics.InitialFacts, solving_settings: expertsystem.reaction.solving.GraphSettings)[source]¶

Bases: object

Particle reaction problem set, defined as a graph like data structure.

Parameters

topology – Topology that contains the structure of the reaction.
initial_facts – InitialFacts that contain the info of initial and final state in connection with the topology.
solving_settings – Solving related settings such as the conservation rules and the quantum number domains.

__eq__(other)¶: Method generated by attrs for class ProblemSet.

initial_facts: expertsystem.reaction.combinatorics.InitialFacts¶

solving_settings: expertsystem.reaction.solving.GraphSettings¶

topology: expertsystem.reaction.topology.Topology¶

class Result(transitions: List[expertsystem.reaction.topology.StateTransitionGraph[Tuple[expertsystem.particle.Particle, float]]] = NOTHING, formalism_type: Optional[str] = None)[source]¶

Bases: object

__eq__(other)¶: Method generated by attrs for class Result.

collapse_graphs() → List[expertsystem.reaction.topology.StateTransitionGraph[expertsystem.particle.ParticleCollection]][source]¶

formalism_type: Optional[str]¶

get_final_state() → List[expertsystem.particle.Particle][source]¶

get_initial_state() → List[expertsystem.particle.Particle][source]¶

get_intermediate_particles() → expertsystem.particle.ParticleCollection [source]¶: Extract the names of the intermediate state particles.

get_particle_graphs() → List[expertsystem.reaction.topology.StateTransitionGraph[expertsystem.particle.Particle]][source]¶

Strip list of StateTransitionGraph s of the spin projections.

Extract a list of StateTransitionGraph instances with only particles on the edges.

See also

Create amplitude models and generate

add_final_state_grouping(fs_group: List[Union[str, List[str]]]) → None [source]¶

create_problem_sets() → Dict[float, List[expertsystem.reaction.ProblemSet]][source]¶

find_solutions(problem_sets: Dict[float, List[expertsystem.reaction.ProblemSet]]) → expertsystem.reaction.Result [source]¶: Check for solutions for a specific set of interaction settings.

property formalism_type¶

set_allowed_interaction_types(allowed_interaction_types: List[expertsystem.reaction.default_settings.InteractionTypes]) → None [source]¶

set_allowed_intermediate_particles(particle_names: List[str]) → None [source]¶

check_reaction_violations(initial_state: Union[str, Tuple[str, Sequence[float]], Sequence[Union[str, Tuple[str, Sequence[float]]]]], final_state: Sequence[Union[str, Tuple[str, Sequence[float]]]], mass_conservation_factor: Optional[float] = 3.0) → Set[FrozenSet[str]][source]¶

Determine violated interaction rules for a given particle reaction.

Warning

This function does only guarantees to find P, C and G parity violations, if it’s a two body decay. If all initial and final states have the C/G parity defined, then these violations are also determined correctly.

Parameters

initial_state – Shortform description of the initial state w/o spin projections.
final_state – Shortform description of the final state w/o spin projections.
mass_conservation_factor – Factor with which the width is multiplied when checking for MassConservation. Set to None in order to deactivate mass conservation.

Returns

Set of least violating rules. The set can have multiple entries, as several quantum numbers can be violated. Each entry in the frozenset represents a group of rules that together violate all possible quantum number configurations.

generate(initial_state: Union[str, Tuple[str, Sequence[float]], Sequence[Union[str, Tuple[str, Sequence[float]]]]], final_state: Sequence[Union[str, Tuple[str, Sequence[float]]]], allowed_intermediate_particles: Optional[List[str]] = None, allowed_interaction_types: Optional[Union[str, List[str]]] = None, formalism_type: str = 'helicity', particles: Optional[expertsystem.particle.ParticleCollection] = None, mass_conservation_factor: Optional[float] = 3.0, topology_building: str = 'isobar', number_of_threads: Optional[int] = None) → expertsystem.reaction.Result [source]¶

Generate allowed transitions between an initial and final state.

Serves as a facade to the StateTransitionManager (see Create amplitude models).

Parameters

initial_state (list) – A list of particle names in the initial state. You can specify spin projections for these particles with a tuple, e.g. ("J/psi(1S)", [-1, 0, +1]). If spin projections are not specified, all projections are taken, so the example here would be equivalent to "J/psi(1S)".
final_state (list) – Same as initial_state, but for final state particles.
allowed_intermediate_particles (list, optional) – A list of particle states that you want to allow as intermediate states. This helps (1) filter out resonances in the eventual AmplitudeModel and (2) speed up computation time.
allowed_interaction_types (str, optional) – Interaction types you want to consider. For instance, both "strong and EM" and ["s", "em"] results in EM and STRONG.
formalism_type (str, optional) – Formalism that you intend to use in the eventual AmplitudeModel.
particles (ParticleCollection, optional) – The particles that you want to be involved in the reaction. Uses load_default_particles by default. It’s better to use a subset for larger reactions, because of the computation times. This argument is especially useful when you want to use your own particle definitions (see Particle database).
mass_conservation_factor – Width factor that is taken into account for for the MassConservation rule.
topology_building (str) –
Technique with which to build the Topology instances. Allowed values are:
- "isobar": Isobar model (each state decays into two states)
- "nbody": Use one central node and connect initial and final states to it
number_of_threads (int) – Number of cores with which to compute the allowed transitions. Defaults to all cores on the system.

An example (where, for illustrative purposes only, we specify all arguments) would be:

>>> import expertsystem as es
>>> result = es.reaction.generate(
...     initial_state="D0",
...     final_state=["K~0", "K+", "K-"],
...     allowed_intermediate_particles=["a(0)(980)", "a(2)(1320)-"],
...     allowed_interaction_types="ew",
...     formalism_type="helicity",
...     particles=es.io.load_pdg(),
...     topology_building="isobar",
... )
>>> len(result.transitions)
4

load_default_particles() → expertsystem.particle.ParticleCollection [source]¶

Load the default particle list that comes with the expertsystem.

Runs load_pdg and supplements its output definitions from the file additional_particle_definitions.yml.

Submodules and Subpackages

PWA Expert System

reaction¶