lips.particle

class lips.particle.Particle(kinematics=None, real_momentum=False, field=('mpc', 0, 300))

Describes the kinematics of a single particle.

angles_for_squares(): Flips left and right spinors.

comp_twist_x(other)

property four_mom: Four Momentum with upper index: P^μ

property four_mom_d: Four Momentum with lower index: P_μ

property l_sp_d: Left spinor with index down: λ̅_α̇ (row vector).

property l_sp_u: Left spinor with index up: λ̅^α̇ (column vector).

lsq(): Lorentz dot product with itself: 2 trace(P^{α̇α}P̅̅_{αα̇}) = P^μ * η_μν * P^ν.

property mass

property r2_sp: Four Momentum Slashed with upper indices: P^{α̇α}

property r2_sp_b: Four Momentum Slashed with lower indices: P̅̅_{αα̇}

property r_sp_d: Right spinor with index down: λ_α (column vector).

property r_sp_u: Right spinor with index up: λ^α (row vector).

randomise(real_momentum=False)

randomise_finite_field()

randomise_mpc(real_momentum=False): Randomises its momentum.

randomise_padic()

randomise_rational()

randomise_twist()

property spinors_are_in_field_extension

twist_x_to_mom(other)

lips.particles

class lips.particles.Particles(number_of_particles_or_particles=None, seed=None, real_momenta=False, field=('mpc', 0, 300), fix_mom_cons=True, internal_masses=None)

Describes the kinematics of n particles. Base one list of Particle objects.

analytical_subs_d()

angles_for_squares(): Switches all angle brackets for square brackets and viceversa.

static check_consistency(temp_string)

cluster(llIntegers): Returns clustered particle objects according to lists of lists of integers (e.g. corners of one loop diagram).

fix_mom_cons(A=0, B=0, real_momenta=False, axis=1): Fixes momentum conservation using particles A and B.

four_momenta_for_mathematica(as_spinors=False)

ijk_to_3Ks(ijk)

ijk_to_3NonOverlappingLists(ijk, mode=1)

image(permutation_or_rule): Returns the image of self under a given permutation or rule. Remember, this is a passive transformation.

insert(index, *args): Insert object before index.

property internal_masses_dict

make_analytical_d(indepVars=None, symbols=('a', 'b', 'c', 'd'))

property masses: Masses of all particles in phase space.

momentum_conservation_check(silent=True): Returns true if momentum is conserved.

property multiplicity

onshell_relation_check(silent=True): Returns true if all on-shell relations are satisfied.

phasespace_consistency_check(invariants=[], silent=True): Runs momentum and onshell checks. Looks for outliers in phase space. Returns: mom_cons, on_shell, big_outliers, small_outliers.

randomise_all(real_momenta=False): Randomises all particles. Breaks momentum conservation.

randomise_twistor()

save_phase_space_point(invariant='')

property spinors_are_in_field_extension

property total_mom: Total momentum of the given phase space as a rank two spinor.

class lips.particles_compute.Particles_Compute

compute(temp_string)

Computes spinor strings.

Available variables: ⟨a|b⟩, [a|b], ⟨a|b+c|d], ⟨a|b+c|d+e|f], …, s_ijk, Δ_ijk, Ω_ijk, Π_ijk, tr5_ijkl

ee(i, j): Contraction of two polarization tensors. Requires .helconf property to be set.

ep(i, j): Contraction of polarization tensor with four momentum. Requires .helconf property to be set.

ldot(A, B): Lorentz dot product: 2 trace(P^{α̇α}P̅̅_{αα̇}) = P_A^μ * η_μν * P_B^ν.

pe(i, j): Contraction of four momentum with polarization tensor. Requires .helconf property to be set.

lips.particles_set

class lips.hardcoded_limits.particles_set.Particles_Set

lips.particles_set_pair

class lips.hardcoded_limits.particles_set_pair.Particles_SetPair

Module contents

Defines tools for phase space manipulations. Particles objects are base one lists of Particle objects.

Particles objects allow to:

Compute spinor strings, through .compute;
Construct single collinear limits, through .set;
Construct double collinear limits, through .set_pair.

oParticles = Particles(multiplicity)
oParticles.randomise_all()
oParticles.fix_mom_cons()
oParticles.compute(spinor_string)
oParticles.set(spinor_string, small_value)
oParticles.set_pair(spinor_string_1, small_value_1, spinor_string_2, small_value_2)