def test_K6_objects(self):
"""Test K6 product simplifications"""
#K6(m,i,j)K6Bar(m,k,l) = 1/2(T(l,i)T(k,j)
# + T(k,i)T(l,j)
my_K6 = color.K6(1,101,102)
my_K6Bar = color.K6Bar(1,103,104)
col_str1 = color.ColorString([color.T(104,101),
color.T(103,102)])
col_str2 = color.ColorString([color.T(103,101),
color.T(104,102)])
col_str1.coeff = fractions.Fraction(1, 2)
col_str2.coeff = fractions.Fraction(1, 2)
self.assertEqual(my_K6.pair_simplify(my_K6Bar),
color.ColorFactor([col_str1, col_str2]))
#K6(m,i,j)K6Bar(n,j,i) = delta6(m,n)
my_K6 = color.K6(1,101,102)
my_K6Bar = color.K6Bar(2,102,101)
self.assertEqual(my_K6.pair_simplify(my_K6Bar),
color.ColorFactor([\
color.ColorString([color.T6(1,2)])]))
#K6(m,i,j)K6Bar(n,i,j) = delta6(m,n).
my_K6 = color.K6(1,101,102)
my_K6Bar = color.K6Bar(2,101,102)
self.assertEqual(my_K6.pair_simplify(my_K6Bar),
color.ColorFactor([\
color.ColorString([color.T6(1,2)])]))
def test_colorize_uu_gg(self):
"""Test the colorize function for uu~ > gg"""
myleglist = base_objects.LegList()
myleglist.append(base_objects.Leg({'id': -2, 'state': False}))
myleglist.append(base_objects.Leg({'id': 2, 'state': False}))
myleglist.extend([base_objects.Leg({'id': 21, 'state': True})] * 2)
myprocess = base_objects.Process({
'legs': myleglist,
'model': self.mymodel
})
myamplitude = diagram_generation.Amplitude()
myamplitude.set('process', myprocess)
myamplitude.generate_diagrams()
my_col_basis = color_amp.ColorBasis()
# S channel
col_dict = my_col_basis.colorize(myamplitude['diagrams'][0],
self.mymodel)
goal_dict = {
(0, 0):
color.ColorString([color.T(-1000, 1, 2),
color.f(3, 4, -1000)])
}
self.assertEqual(col_dict, goal_dict)
# T channel
col_dict = my_col_basis.colorize(myamplitude['diagrams'][1],
self.mymodel)
goal_dict = {
(0, 0):
color.ColorString([color.T(3, 1, -1000),
color.T(4, -1000, 2)])
}
self.assertEqual(col_dict, goal_dict)
# U channel
col_dict = my_col_basis.colorize(myamplitude['diagrams'][2],
self.mymodel)
goal_dict = {
(0, 0):
color.ColorString([color.T(4, 1, -1000),
color.T(3, -1000, 2)])
}
self.assertEqual(col_dict, goal_dict)
def test_delta3_pair_simplify(self):
"""Test delta3 simplify"""
self.assertEqual(color.K6(1,101,103).pair_simplify(color.T(101,102)),
color.ColorFactor([color.ColorString([color.K6(1,103,102)])]))
self.assertEqual(color.K6(1,103,102).pair_simplify(color.T(102,101)),
color.ColorFactor([color.ColorString([color.K6(1,103,101)])]))
self.assertEqual(color.K6Bar(1,101,103).pair_simplify(color.T(102,101)),
color.ColorFactor([color.ColorString([color.K6Bar(1,103,102)])]))
self.assertEqual(color.K6Bar(1,103,101).pair_simplify(color.T(102,101)),
color.ColorFactor([color.ColorString([color.K6Bar(1,103,102)])]))
def test_epsilon_object(self):
"""Test the epsilon object"""
# Espilon should have exactly 3 indices!
self.assertRaises(AssertionError, color.Epsilon, 1, 2)
my_epsilon1 = color.Epsilon(2, 3, 1)
my_epsilon2 = color.Epsilon(5, 1, 4)
my_epsilon2 = my_epsilon2.complex_conjugate()
my_goal_str1 = color.ColorString([color.T(2, 4), color.T(3, 5)])
my_goal_str2 = color.ColorString([color.T(2, 5), color.T(3, 4)])
my_goal_str2.coeff = fractions.Fraction(-1)
self.assertEqual(my_epsilon1.pair_simplify(my_epsilon2),
color.ColorFactor([my_goal_str1, my_goal_str2]))
def closeColorLoop(self, colorize_dict, lcut_charge, lcut_numbers):
""" Add a color delta in the right representation (depending on the
color charge carried by the L-cut particle whose number are given in
the loop_numbers argument) to close the loop color trace """
# But for T3 and T6 for example, we must make sure to add a delta with
# the first index in the fundamental representation.
if lcut_charge < 0:
lcut_numbers.reverse()
if abs(lcut_charge) == 1:
# No color carried by the lcut particle, there is nothing to do.
return
elif abs(lcut_charge) == 3:
closingCS=color_algebra.ColorString(\
[color_algebra.T(lcut_numbers[1],lcut_numbers[0])])
elif abs(lcut_charge) == 6:
closingCS=color_algebra.ColorString(\
[color_algebra.T6(lcut_numbers[1],lcut_numbers[0])])
elif abs(lcut_charge) == 8:
closingCS=color_algebra.ColorString(\
[color_algebra.Tr(lcut_numbers[1],lcut_numbers[0])],
fractions.Fraction(2, 1))
else:
raise color_amp.ColorBasis.ColorBasisError, \
"L-cut particle has an unsupported color representation %s" % lcut_charge
# Append it to all color strings for this diagram.
for CS in colorize_dict.values():
CS.product(closingCS)
def get_color_flow_string(my_color_string, octet_indices):
"""Return the color_flow_string (i.e., composed only of T's with 2
indices) associated to my_color_string. Take a list of the external leg
color octet state indices as an input. Returns only the leading N
contribution!"""
# Create a new color factor to allow for simplification
my_cf = color_algebra.ColorFactor([my_color_string])
# Add one T per external octet
for indices in octet_indices:
if indices[0] == -6:
# Add a K6 which contracts the antisextet index to a
# pair of antitriplets
my_cf[0].append(
color_algebra.K6(indices[1], indices[2], indices[3]))
if indices[0] == 6:
# Add a K6Bar which contracts the sextet index to a
# pair of triplets
my_cf[0].append(
color_algebra.K6Bar(indices[1], indices[2], indices[3]))
if abs(indices[0]) == 8:
# Add a T which contracts the octet to a
# triplet-antitriplet pair
my_cf[0].append(
color_algebra.T(indices[1], indices[2], indices[3]))
# Simplify the whole thing
my_cf = my_cf.full_simplify()
# If the result is empty, just return
if not my_cf:
return my_cf
# Return the string with the highest N coefficient
# (leading N decomposition), and the value of this coeff
max_coeff = max([cs.Nc_power for cs in my_cf])
res_cs = [cs for cs in my_cf if cs.Nc_power == max_coeff]
# If more than one string at leading N...
if len(res_cs) > 1 and any([not cs.near_equivalent(res_cs[0]) \
for cs in res_cs]):
raise ColorBasis.ColorBasisError, \
"More than one color string with leading N coeff: %s" % str(res_cs)
res_cs = res_cs[0]
# If the result string does not contain only T's with two indices
# and Epsilon/EpsilonBar objects
for col_obj in res_cs:
if not isinstance(col_obj, color_algebra.T) and \
not col_obj.__class__.__name__.startswith('Epsilon'):
raise ColorBasis.ColorBasisError, \
"Color flow decomposition %s contains non T/Epsilon elements" % \
str(res_cs)
if isinstance(col_obj, color_algebra.T) and len(col_obj) != 2:
raise ColorBasis.ColorBasisError, \
"Color flow decomposition %s contains T's w/o 2 indices" % \
str(res_cs)
return res_cs
def closeColorLoop(self, colorize_dict, lcut_charge, lcut_numbers):
""" Add a color delta in the right representation (depending on the
color charge carried by the L-cut particle whose number are given in
the loop_numbers argument) to close the loop color trace."""
# But for T3 and T6 for example, we must make sure to add a delta with
# the first index in the fundamental representation.
if lcut_charge < 0:
lcut_numbers.reverse()
if abs(lcut_charge) == 1:
# No color carried by the lcut particle, there is nothing to do.
return
elif abs(lcut_charge) == 3:
closingCS=color_algebra.ColorString(\
[color_algebra.T(lcut_numbers[1],lcut_numbers[0])])
elif abs(lcut_charge) == 6:
closingCS=color_algebra.ColorString(\
[color_algebra.T6(lcut_numbers[1],lcut_numbers[0])])
elif abs(lcut_charge) == 8:
closingCS=color_algebra.ColorString(\
[color_algebra.Tr(lcut_numbers[1],lcut_numbers[0])],
fractions.Fraction(2, 1))
else:
raise color_amp.ColorBasis.ColorBasisError, \
"L-cut particle has an unsupported color representation %s" % lcut_charge
# Append it to all color strings for this diagram.
for CS in colorize_dict.values():
# The double full_simplify() below brings significantly slowdown
# so that it should be used only when loop_Nc_power is actuall used.
if self.compute_loop_nc:
# We first compute the NcPower of this ColorString before
# *before* the loop color flow is sewed together.
max_CS_lcut_diag_Nc_power = max(cs.Nc_power \
for cs in color_algebra.ColorFactor([CS]).full_simplify())
# We add here the closing color structure.
CS.product(closingCS)
if self.compute_loop_nc:
# Now compute the Nc power *after* the loop color flow is sewed
# together and again compute the overall maximum power of Nc
# appearing in this simplified sewed structure.
simplified_cs = color_algebra.ColorFactor([CS]).full_simplify()
if not simplified_cs:
# It can be that the color structure simplifies to zero.
CS.loop_Nc_power = 0
continue
max_CS_loop_diag_Nc_power = max(cs.Nc_power \
for cs in simplified_cs)
# We can now set the power of Nc brought by the potential loop
# color trace to the corresponding attribute of this ColorStructure
CS.loop_Nc_power = max_CS_loop_diag_Nc_power - \
max_CS_lcut_diag_Nc_power
else:
# When not computing loop_nc (whcih is typically used for now
# only when doing LoopInduced + Madevent, we set the
# CS.loop_Nc_power to None so that it will cause problems if used.
CS.loop_Nc_power = None
def test_complex_conjugate(self):
"""Test the complex conjugation of a color string"""
my_color_string = color.ColorString([color.T(3, 4, 102, 103),
color.Tr(1, 2, 3)])
my_color_string.is_imaginary = True
self.assertEqual(str(my_color_string.complex_conjugate()),
'-1 I T(4,3,103,102) Tr(3,2,1)')
def test_T_simplify(self):
"""Test T simplify"""
# T(a,b,c,...,i,i) = Tr(a,b,c,...)
self.assertEqual(color.T(1, 2, 3, 100, 100).simplify(),
color.ColorFactor([\
color.ColorString([color.Tr(1, 2, 3)])]))
# T(a,x,b,x,c,i,j) = 1/2(T(a,c,i,j)Tr(b)-1/Nc T(a,b,c,i,j))
my_T = color.T(1, 2, 100, 3, 100, 4, 101, 102)
col_str1 = color.ColorString([color.T(1, 2, 4, 101, 102), color.Tr(3)])
col_str2 = color.ColorString([color.T(1, 2, 3, 4, 101, 102)])
col_str1.coeff = fractions.Fraction(1, 2)
col_str2.coeff = fractions.Fraction(-1, 2)
col_str2.Nc_power = -1
self.assertEqual(my_T.simplify(),
color.ColorFactor([col_str1, col_str2]))
self.assertEqual(my_T.simplify(),
color.ColorFactor([col_str1, col_str2]))
def test_T_f_product(self):
"""Test a non trivial T f f product"""
my_color_factor = color.ColorFactor([\
color.ColorString([color.T(-1000, 1, 2),
color.f(-1, -1000, 5),
color.f(-1, 4, 3)])])
self.assertEqual(str(my_color_factor.full_simplify()),
"(-1 T(5,4,3,1,2))+(1 T(5,3,4,1,2))+(1 T(4,3,5,1,2))+(-1 T(3,4,5,1,2))")
def test_replace_indices(self):
"""Test indices replacement"""
repl_dict = {1: 2, 2: 3, 3: 1}
my_color_string = color.ColorString(
[color.T(1, 2, 3, 4), color.Tr(3, 2, 1)])
my_color_string.replace_indices(repl_dict)
self.assertEqual(str(my_color_string), '1 T(2,3,1,4) Tr(1,3,2)')
inv_repl_dict = dict([v, k] for k, v in repl_dict.items())
my_color_string.replace_indices(inv_repl_dict)
self.assertEqual(str(my_color_string), '1 T(1,2,3,4) Tr(3,2,1)')
def test_Tr_pair_simplify(self):
"""Test Tr object product simplification"""
my_Tr1 = color.Tr(1, 2, 3)
my_Tr2 = color.Tr(4, 2, 5)
my_T = color.T(4, 2, 5, 101, 102)
col_str1 = color.ColorString([color.Tr(1, 5, 4, 3)])
col_str2 = color.ColorString([color.Tr(1, 3), color.Tr(4, 5)])
col_str1.coeff = fractions.Fraction(1, 2)
col_str2.coeff = fractions.Fraction(-1, 2)
col_str2.Nc_power = -1
self.assertEqual(my_Tr1.pair_simplify(my_Tr2),
color.ColorFactor([col_str1, col_str2]))
col_str1 = color.ColorString([color.T(4, 3, 1, 5, 101, 102)])
col_str2 = color.ColorString([color.Tr(1, 3), color.T(4, 5, 101, 102)])
col_str1.coeff = fractions.Fraction(1, 2)
col_str2.coeff = fractions.Fraction(-1, 2)
col_str2.Nc_power = -1
self.assertEqual(my_Tr1.pair_simplify(my_T),
color.ColorFactor([col_str1, col_str2]))
def test_T6_simplify(self):
"""Test T6 simplify"""
# T6(a,i,j) = 2(K6(i,ii,jj)T(a,jj,kk)K6Bar(j,kk,ii))
my_T6 = color.T6(1,101,102)
color.T6.new_index = 10000
k6 = color.K6(101, 10000, 10001)
t = color.T(1, 10001, 10002)
k6b = color.K6Bar(102, 10002, 10000)
col_string = color.ColorString([k6, t, k6b])
col_string.coeff = fractions.Fraction(2, 1)
self.assertEqual(my_T6.simplify(), color.ColorFactor([col_string]))
my_T6 = color.T6(1,101,102)
k6 = color.K6(101, 10003, 10004)
t = color.T(1, 10004, 10005)
k6b = color.K6Bar(102, 10005, 10003)
col_string = color.ColorString([k6, t, k6b])
col_string.coeff = fractions.Fraction(2, 1)
self.assertEqual(my_T6.simplify(), color.ColorFactor([col_string]))
def test_color_flow_string_epsilon(self):
"""Test the color flow decomposition of strings including Epsilon
and color sextets"""
# g q > trip q
my_cs = color.ColorString(
[color.Epsilon(-1000, 2, 3),
color.T(1, 4, -1000)])
goal_cs = color.ColorString(
[color.T(4, 2001), color.Epsilon(1001, 2, 3)])
goal_cs.coeff = fractions.Fraction(1, 2)
self.assertEqual(
color_amp.ColorBasis.get_color_flow_string(my_cs,
[(8, 1, 1001, 2001)]),
goal_cs)
# g q > six q~
my_cs = color.ColorString(
[color.K6(3, -1000, 4),
color.T(1, -1000, 2)])
goal_cs = color.ColorString(
[color.T(1001, 2),
color.T(1003, 4),
color.T(3003, 2001)])
goal_cs.coeff = fractions.Fraction(1, 4)
self.assertEqual(
color_amp.ColorBasis.get_color_flow_string(my_cs,
[(8, 1, 1001, 2001),
(6, 3, 1003, 3003)]),
goal_cs)
# g q~ > trip > q~ q q~
my_cs = color.ColorString([
color.Epsilon(-1000, 2, 4),
color.EpsilonBar(-1001, 3, 5),
color.T(1, -1001, -1000)
])
goal_cs = color.ColorString(
[color.Epsilon(1001, 2, 4),
color.EpsilonBar(2001, 3, 5)])
goal_cs.coeff = fractions.Fraction(1, 2)
self.assertEqual(
color_amp.ColorBasis.get_color_flow_string(my_cs,
[(8, 1, 1001, 2001)]),
goal_cs)
def test_T_pair_simplify(self):
"""Test T object products simplifications"""
my_T1 = color.T(1, 2, 3, 101, 102)
my_T2 = color.T(4, 5, 102, 103)
self.assertEqual(my_T1.pair_simplify(my_T2),
color.ColorFactor([color.ColorString([\
color.T(1, 2, 3, 4, 5, 101, 103)])]))
my_T3 = color.T(4, 2, 5, 103, 104)
col_str1 = color.ColorString([color.T(1, 5, 101, 104),
color.T(4, 3, 103, 102)])
col_str2 = color.ColorString([color.T(1, 3, 101, 102),
color.T(4, 5, 103, 104)])
col_str1.coeff = fractions.Fraction(1, 2)
col_str2.coeff = fractions.Fraction(-1, 2)
col_str2.Nc_power = -1
self.assertEqual(my_T1.pair_simplify(my_T3),
color.ColorFactor([col_str1, col_str2]))
def test_ungrouping_lepton(self):
"""check that the routines which ungroup the process for the muon/electron processes
works as expected"""
# Setup A simple model
mypartlist = base_objects.ParticleList()
myinterlist = base_objects.InteractionList()
# A quark U and its antiparticle
mypartlist.append(
base_objects.Particle({
'name': 'u',
'antiname': 'u~',
'spin': 2,
'color': 3,
'mass': 'zero',
'width': 'zero',
'texname': 'u',
'antitexname': '\bar u',
'line': 'straight',
'charge': 2. / 3.,
'pdg_code': 2,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
u = mypartlist[-1]
antiu = copy.copy(u)
antiu.set('is_part', False)
# A quark D and its antiparticle
mypartlist.append(
base_objects.Particle({
'name': 'd',
'antiname': 'd~',
'spin': 2,
'color': 3,
'mass': 'zero',
'width': 'zero',
'texname': 'd',
'antitexname': '\bar d',
'line': 'straight',
'charge': -1. / 3.,
'pdg_code': 1,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
d = mypartlist[-1]
antid = copy.copy(d)
antid.set('is_part', False)
# A quark C and its antiparticle
mypartlist.append(
base_objects.Particle({
'name': 'c',
'antiname': 'c~',
'spin': 2,
'color': 3,
'mass': 'zero',
'width': 'zero',
'texname': 'u',
'antitexname': '\bar u',
'line': 'straight',
'charge': 2. / 3.,
'pdg_code': 4,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
c = mypartlist[-1]
antic = copy.copy(c)
antic.set('is_part', False)
# electron/positront
mypartlist.append(
base_objects.Particle({
'name': 'e-',
'antiname': 'e+',
'spin': 2,
'color': 1,
'mass': 'zero',
'width': 'zero',
'texname': 'u',
'antitexname': '\bar u',
'line': 'straight',
'charge': 1,
'pdg_code': 11,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
e = mypartlist[-1]
antie = copy.copy(e)
mu = copy.copy(e)
antie.set('is_part', False)
mu.set('name', 'mu-')
mu.set('antiname', 'mu+')
mu.set('pdg_code', 13)
mypartlist.append(mu)
antimu = copy.copy(mu)
antimu.set('is_part', False)
# A Z
mypartlist.append(
base_objects.Particle({
'name': 'z',
'antiname': 'z',
'spin': 3,
'color': 1,
'mass': 'MZ',
'width': 'WZ',
'texname': 'Z',
'antitexname': 'Z',
'line': 'wavy',
'charge': 0.,
'pdg_code': 23,
'propagating': True,
'is_part': True,
'self_antipart': True
}))
z = mypartlist[-1]
# Coupling of Z to quarks
myinterlist.append(base_objects.Interaction({
'id': 1,
'particles': base_objects.ParticleList(\
[antiu, \
u, \
z]),
'color': [color.ColorString([color.T(1,0)])],
'lorentz':['FFV1', 'FFV2'],
'couplings':{(0, 0):'GUZ1', (0, 1):'GUZ2'},
'orders':{'QED':1}}))
myinterlist.append(base_objects.Interaction({
'id': 2,
'particles': base_objects.ParticleList(\
[antid, \
d, \
z]),
'color': [color.ColorString([color.T(1,0)])],
'lorentz':['FFV1', 'FFV2'],
'couplings':{(0, 0):'GDZ1', (0, 1):'GDZ2'},
'orders':{'QED':1}}))
myinterlist.append(base_objects.Interaction({
'id': 3,
'particles': base_objects.ParticleList(\
[antic, \
c, \
z]),
'color': [color.ColorString([color.T(1,0)])],
'lorentz':['FFV1', 'FFV2'],
'couplings':{(0, 0):'GUZ1', (0, 1):'GUZ2'},
'orders':{'QED':1}}))
# Coupling of Z to leptons
myinterlist.append(base_objects.Interaction({
'id': 4,
'particles': base_objects.ParticleList(\
[antie, \
e, \
z]),
'color': [color.ColorString()],
'lorentz':['FFV1', 'FFV2'],
'couplings':{(0, 0):'GLZ1', (0, 1):'GLZ2'},
'orders':{'QED':1}}))
# Coupling of Z to leptons
myinterlist.append(base_objects.Interaction({
'id': 5,
'particles': base_objects.ParticleList(\
[antimu, \
mu, \
z]),
'color': [color.ColorString()],
'lorentz':['FFV1', 'FFV2'],
'couplings':{(0, 0):'GLZ1', (0, 1):'GLZ2'},
'orders':{'QED':1}}))
mymodel = base_objects.Model()
mymodel.set('particles', mypartlist)
mymodel.set('interactions', myinterlist)
mymodel.set('name', 'sm')
procs = [[1, -1, 23], [2, -2, 23], [4, -4, 23]]
decays = [[23, 11, -11], [23, 13, -13]]
coreamplitudes = diagram_generation.AmplitudeList()
decayamplitudes = diagram_generation.AmplitudeList()
decayprocs = base_objects.ProcessList()
#Building the basic objects
for proc in procs:
# Define the multiprocess
my_leglist = base_objects.LegList([\
base_objects.Leg({'id': id, 'state': True}) for id in proc])
my_leglist[0].set('state', False)
my_leglist[1].set('state', False)
my_process = base_objects.Process({
'legs': my_leglist,
'model': mymodel
})
my_amplitude = diagram_generation.Amplitude(my_process)
my_amplitude.set('has_mirror_process', True)
coreamplitudes.append(my_amplitude)
for proc in decays:
# Define the multiprocess
my_leglist = base_objects.LegList([\
base_objects.Leg({'id': id, 'state': True}) for id in proc])
my_leglist[0].set('state', False)
my_process = base_objects.Process({
'legs': my_leglist,
'model': mymodel,
'is_decay_chain': True
})
my_amplitude = diagram_generation.Amplitude(my_process)
decayamplitudes.append(my_amplitude)
decayprocs.append(my_process)
decays = diagram_generation.DecayChainAmplitudeList([\
diagram_generation.DecayChainAmplitude({\
'amplitudes': decayamplitudes})])
decay_chains = diagram_generation.DecayChainAmplitude({\
'amplitudes': coreamplitudes,
'decay_chains': decays})
dc_subproc_group = group_subprocs.DecayChainSubProcessGroup.\
group_amplitudes(\
diagram_generation.DecayChainAmplitudeList([decay_chains]))
subproc_groups = \
dc_subproc_group.generate_helas_decay_chain_subproc_groups()
######################
## Make the test!! ##
######################
self.assertEqual(len(subproc_groups), 1)
subproc_groups = subproc_groups.split_lepton_grouping()
self.assertEqual(len(subproc_groups), 2)
# check that indeed
for group in subproc_groups:
self.assertEqual(len(group['matrix_elements']), 2)
has_muon = any(
abs(l['id']) == 13 for l in group['matrix_elements'][0]
['processes'][0]['decay_chains'][0]['legs'])
for me in group['matrix_elements']:
if abs(me['processes'][0]['legs'][0]['id']) == 1:
self.assertEqual(len(me['processes']), 1)
else:
self.assertEqual(len(me['processes']), 2)
for proc in me['processes']:
for dec in proc['decay_chains']:
if has_muon:
self.assertFalse(
any(abs(l['id']) == 11 for l in dec['legs']))
else:
self.assertFalse(
any(abs(l['id']) == 13 for l in dec['legs']))
self.assertNotEqual(group['name'], 'qq_z_z_ll')
if has_muon:
self.assertEqual(group['name'], 'qq_z_z_mummup')
else:
self.assertEqual(group['name'], 'qq_z_z_emep')
group['name']
def legs_to_color_link_string(leg1, leg2): #test written, all cases
"""given two FKSlegs, returns a dictionary containing:
--string: the color link between the two particles, to be appended to
the old color string
extra minus or 1/2 factor are included as it was done in MadDipole
--replacements: a pair of lists containing the replacements of the color
indices in the old string to match the link
"""
#the second-to-last index of the t is the triplet,
# the last is the anti-triplet
legs = FKSLegList([leg1, leg2])
dict = {}
min_index = -3000
iglu = min_index * 2
string = color_algebra.ColorString()
replacements = []
if leg1 != leg2:
for leg in legs:
min_index -= 1
num = leg.get('number')
replacements.append([num, min_index])
icol = 1
if not leg.get('state'):
icol = -1
if leg.get('color') * icol == 3:
string.product(
color_algebra.ColorString(
[color_algebra.T(iglu, num, min_index)]))
string.coeff = string.coeff * (-1)
elif leg.get('color') * icol == -3:
string.product(
color_algebra.ColorString(
[color_algebra.T(iglu, min_index, num)]))
elif leg.get('color') == 8:
string.product(
color_algebra.ColorString(
init_list=[color_algebra.f(min_index, iglu, num)],
is_imaginary=True))
else:
icol = 1
if not leg1.get('state'):
icol = -1
num = leg1.get('number')
replacements.append([num, min_index - 1])
if leg1.get('color') * icol == 3:
string = color_algebra.ColorString(
[color_algebra.T(iglu, iglu, num, min_index - 1)])
elif leg1.get('color') * icol == -3:
string = color_algebra.ColorString(
[color_algebra.T(iglu, iglu, min_index - 1, num)])
elif leg1.get('color') == 8:
string = color_algebra.ColorString(
init_list=[color_algebra.f(min_index - 1, iglu, min_index)],
is_imaginary=True)
string.product(
color_algebra.ColorString(
init_list=[color_algebra.f(min_index, iglu, num)],
is_imaginary=True))
string.coeff = string.coeff * fractions.Fraction(1, 2)
dict['replacements'] = replacements
dict['string'] = string
return dict
color.ColorString([color.f(-1, 0, 2), color.f(-1, 1, 3)]),
color.ColorString([color.f(-1, 0, 3), color.f(-1, 1, 2)]),
color.ColorString([color.f(-1, 0, 1), color.f(-1, 2, 3)])
],
'lorentz': ['L(p1,p2,p3)', 'L(p2,p3,p1)', 'L3'],
'couplings': {(0, 0): 'G^2', (1, 1): 'G^2', (2, 2): 'G^2'},
'orders': {'QCD': 2}
}))
# u u~ g
interactions.append(base_objects.Interaction({
'id': 3,
'particles': base_objects.ParticleList([
up, antiup, gluon
]),
'color': [color.ColorString([color.T(2, 0, 1)])],
'lorentz': ['L1'],
'couplings': {(0, 0): 'GQQ'},
'orders': {'QCD': 1}
}))
# d d~ g
interactions.append(base_objects.Interaction({
'id': 4,
'particles': base_objects.ParticleList([
down, antidown, gluon
]),
'color': [color.ColorString([color.T(2, 0, 1)])],
'lorentz': ['L1'],
'couplings': {(0, 0): 'GQQ'},
'orders': {'QCD': 1}
def test_read_interactions(self):
"""Test the output of import interactions.dat file"""
particles_dat_str = """ve ve~ F S ZERO ZERO S ve 12
vm vm~ F S ZERO ZERO S vm 14
vt vt~ F S ZERO ZERO S vt 16
e- e+ F S ZERO ZERO S e 11
m- m+ F S ZERO ZERO S m 13
tt- tt+ F S MTA ZERO S tt 15
u u~ F S ZERO ZERO T u 2
c c~ F S MC ZERO T c 4
t t~ F S MT WT T t 6
d d~ F S ZERO ZERO T d 1
s s~ F S ZERO ZERO T s 3
b b~ F S MB ZERO T b 5
a a V W ZERO ZERO S a 22
z z V W MZ WZ S Z 23
w+ w- V W MW WW S W 24
g g V C ZERO ZERO O G 21
h h S D MH WH S H 25
T1 T1 T D ZERO ZERO O T1 8000002"""
interactions_dat_str = """# Interactions associated with Standard_Model
w+ w- a MGVX3 QED
g g T1 MGVX2 QCD a
w+ w- w+ w- MGVX6 DUM0 QED QED n
e- ve w- MGVX24 QED
e+ ve~ w+ MGVX25 QED
u u g MGVX1 QCD
u u a MGVX4 QED
# And now some bad format entries
# which should be ignored with a warning
k+ k- a test QED
g g test QCD"""
fsock_part = StringIO.StringIO(particles_dat_str)
fsock_inter = StringIO.StringIO(interactions_dat_str)
myparts = import_v4.read_particles_v4(fsock_part)
wplus = copy.copy(myparts[14])
wmin = copy.copy(myparts[14])
wmin.set('is_part', False)
eminus = copy.copy(myparts[3])
eplus = copy.copy(myparts[3])
eplus.set('is_part', False)
enu = copy.copy(myparts[0])
enubar = copy.copy(myparts[0])
enubar.set('is_part', False)
photon = copy.copy(myparts[12])
gluon = copy.copy(myparts[15])
t1 = copy.copy(myparts[17])
u = myparts[6]
ubar = copy.copy(myparts[6])
ubar.set('is_part', False)
my_i_f = color.ColorString([color.f(0, 1, 2)])
my_i_f.is_imaginary = True
goal_inter_list = base_objects.InteractionList([ \
base_objects.Interaction(
{'id':1,
'particles':base_objects.ParticleList([
wplus,
wmin,
photon]),
'color':[],
'lorentz':[''],
'couplings':{(0, 0):'MGVX3'},
'orders':{'QED':1}}),
base_objects.Interaction(
{'id':2,
'particles':base_objects.ParticleList([
gluon,
gluon,
t1]),
'color':[my_i_f],
'lorentz':['A'],
'couplings':{(0, 0):'MGVX2'},
'orders':{'QCD':1}}),
base_objects.Interaction(
{'id':3,
'particles':base_objects.ParticleList([
wplus,
wmin,
wplus,
wmin]),
'color':[],
'lorentz':['WWVVN'],
'couplings':{(0, 0):'MGVX6'},
'orders':{'QED':2}}),
base_objects.Interaction(
{'id':4,
'particles':base_objects.ParticleList([
eplus,
enu,
wmin]),
'color':[],
'lorentz':[''],
'couplings':{(0, 0):'MGVX24'},
'orders':{'QED':1}}),
base_objects.Interaction(
{'id':5,
'particles':base_objects.ParticleList([
eminus,
enubar,
wplus]),
'color':[],
'lorentz':[''],
'couplings':{(0, 0):'MGVX25'},
'orders':{'QED':1}}),
base_objects.Interaction(
{'id':6,
'particles':base_objects.ParticleList([
ubar,
u,
gluon]),
'color':[color.ColorString(\
[color.T(2, 1, 0)])],
'lorentz':[''],
'couplings':{(0, 0):'MGVX1'},
'orders':{'QCD':1}}),
base_objects.Interaction(
{'id':7,
'particles':base_objects.ParticleList([
ubar,
u,
photon]),
'color':[color.ColorString(\
[color.T(1, 0)])],
'lorentz':[''],
'couplings':{(0, 0):'MGVX4'},
'orders':{'QED':1}})])
result = import_v4.read_interactions_v4(fsock_inter, myparts)
self.assertEqual(len(result), len(goal_inter_list))
for i in range(len(result)):
self.assertEqual(result[i], goal_inter_list[i])
def test_sextet_products(self):
"""Test non trivial product of sextet operators"""
# T6[2, 101, 102] T6[2, 102, 103] = (-1 + Nc) (2 + Nc) delta6[101, 103])/Nc
my_color_factor = color.ColorFactor([\
color.ColorString([color.T6(2, 101, 102),
color.T6(2, 102, 103)])])
col_str1 = color.ColorString([color.T6(101,103)])
col_str1.Nc_power = 1
col_str2 = copy.copy(col_str1)
col_str2.Nc_power = 0
col_str3 = copy.copy(col_str1)
col_str3.Nc_power = -1
col_str3.coeff = fractions.Fraction(-2, 1)
self.assertEqual(my_color_factor.full_simplify(),
color.ColorFactor([col_str1, col_str2, col_str3]))
# T6[2, 101, 102] T6[3, 102, 101] = 1/2 (2 + Nc) delta8[2, 3]
my_color_factor = color.ColorFactor([\
color.ColorString([color.T6(2, 101, 102),
color.T6(3, 102, 101)])])
col_str1 = color.ColorString([color.Tr(2,3)])
col_str1.Nc_power = 1
col_str1.coeff = fractions.Fraction(1)
col_str2 = copy.copy(col_str1)
col_str2.Nc_power = 0
col_str2.coeff = fractions.Fraction(2)
self.assertEqual(my_color_factor.full_simplify(),
color.ColorFactor([col_str1, col_str2]))
# K6[1, 101, 102] T[2, 102, 103] T[2, 103, 104] K6Bar[1, 104, 101]
# = 1/4 (-1 + Nc) (1 + Nc)^2
# = 1/4 (-1 - Nc + Nc^2 + Nc^3)
my_color_factor = color.ColorFactor([\
color.ColorString([color.K6(1, 101, 102),
color.T(2, 102, 103),
color.T(2, 103, 104),
color.K6Bar(1, 104, 101)])])
col_str1 = color.ColorString()
col_str1.Nc_power = 3
col_str1.coeff = fractions.Fraction(1, 4)
col_str2 = color.ColorString()
col_str2.Nc_power = 2
col_str2.coeff = fractions.Fraction(1, 4)
col_str3 = color.ColorString()
col_str3.Nc_power = 1
col_str3.coeff = fractions.Fraction(-1, 4)
col_str4 = color.ColorString()
col_str4.Nc_power = 0
col_str4.coeff = fractions.Fraction(-1, 4)
self.assertEqual(my_color_factor.full_simplify(),
color.ColorFactor([col_str1, col_str3,
col_str2, col_str4]))
# T6[2, 101, 102] T6[2, 102, 103] K6[103, 99, 98] K6Bar[101, 98, 99]
# = 1/2 (-1 + Nc) (1 + Nc) (2 + Nc)
# = 1/2 (Nc^3 + 2 Nc^2 - Nc - 2)
my_color_factor = color.ColorFactor([\
color.ColorString([color.T6(2, 101, 102),
color.T6(2, 102, 103),
color.K6(103,99, 98),
color.K6Bar(101, 98, 99)])])
col_str1 = color.ColorString()
col_str1.Nc_power = 3
col_str1.coeff = fractions.Fraction(1, 2)
col_str2 = color.ColorString()
col_str2.Nc_power = 2
col_str2.coeff = fractions.Fraction(1, 1)
col_str3 = color.ColorString()
col_str3.Nc_power = 1
col_str3.coeff = fractions.Fraction(-1, 2)
col_str4 = color.ColorString()
col_str4.Nc_power = 0
col_str4.coeff = fractions.Fraction(-1, 1)
self.assertEqual(my_color_factor.full_simplify(),
color.ColorFactor([col_str2, col_str1,
col_str3, col_str4]))
# K6[103, 99, 98] T[80, 98, 100] K6Bar[103, 100, 97] T[80, 99, 97]
# = -(1/4) + Nc^2/4
my_color_factor = color.ColorFactor([\
color.ColorString([color.K6(103, 99, 98),
color.T(80, 98, 100),
color.K6Bar(103, 100, 97),
color.T(80, 99, 97)])])
col_str1 = color.ColorString()
col_str1.Nc_power = 2
col_str1.coeff = fractions.Fraction(1, 4)
col_str2 = color.ColorString()
col_str2.Nc_power = 0
col_str2.coeff = fractions.Fraction(-1, 4)
self.assertEqual(my_color_factor.full_simplify(),
color.ColorFactor([col_str1, col_str2]))
def test_colorize_uux_ggg(self):
"""Test the colorize function for uu~ > ggg"""
myleglist = base_objects.LegList()
myleglist.append(base_objects.Leg({'id': 2, 'state': False}))
myleglist.append(base_objects.Leg({'id': -2, 'state': False}))
myleglist.extend([base_objects.Leg({'id': 21, 'state': True})] * 3)
myprocess = base_objects.Process({
'legs': myleglist,
'model': self.mymodel
})
myamplitude = diagram_generation.Amplitude()
myamplitude.set('process', myprocess)
myamplitude.generate_diagrams()
my_col_basis = color_amp.ColorBasis()
# First diagram with two 3-gluon vertices
col_dict = my_col_basis.colorize(myamplitude['diagrams'][0],
self.mymodel)
goal_dict = {
(0, 0, 0):
color.ColorString([
color.T(-1000, 2, 1),
color.f(-1001, 3, 4),
color.f(-1000, -1001, 5)
])
}
self.assertEqual(col_dict, goal_dict)
# Diagram with one 4-gluon vertex
col_dict = my_col_basis.colorize(myamplitude['diagrams'][3],
self.mymodel)
goal_dict = {
(0, 0):
color.ColorString([
color.T(-1000, 2, 1),
color.f(-1001, 3, 5),
color.f(-1001, 4, -1000)
]),
(0, 1):
color.ColorString([
color.T(-1000, 2, 1),
color.f(-1002, 3, -1000),
color.f(-1002, 4, 5)
]),
(0, 2):
color.ColorString([
color.T(-1000, 2, 1),
color.f(-1003, 3, 4),
color.f(-1003, 5, -1000)
])
}
self.assertEqual(col_dict, goal_dict)
def setUp(self):
# Set up model
mypartlist = base_objects.ParticleList()
myinterlist = base_objects.InteractionList()
# u and c quarkd and their antiparticles
mypartlist.append(
base_objects.Particle({
'name': 'u',
'antiname': 'u~',
'spin': 2,
'color': 3,
'mass': 'ZERO',
'width': 'ZERO',
'texname': 'u',
'antitexname': '\bar u',
'line': 'straight',
'charge': 2. / 3.,
'pdg_code': 2,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
u = mypartlist[len(mypartlist) - 1]
antiu = copy.copy(u)
antiu.set('is_part', False)
mypartlist.append(
base_objects.Particle({
'name': 'c',
'antiname': 'c~',
'spin': 2,
'color': 3,
'mass': 'MC',
'width': 'ZERO',
'texname': 'c',
'antitexname': '\bar c',
'line': 'straight',
'charge': 2. / 3.,
'pdg_code': 4,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
c = mypartlist[len(mypartlist) - 1]
antic = copy.copy(c)
antic.set('is_part', False)
# A gluon
mypartlist.append(
base_objects.Particle({
'name': 'g',
'antiname': 'g',
'spin': 3,
'color': 8,
'mass': 'ZERO',
'width': 'ZERO',
'texname': 'g',
'antitexname': 'g',
'line': 'curly',
'charge': 0.,
'pdg_code': 21,
'propagating': True,
'is_part': True,
'self_antipart': True
}))
g = mypartlist[len(mypartlist) - 1]
# A photon
mypartlist.append(
base_objects.Particle({
'name': 'Z',
'antiname': 'Z',
'spin': 3,
'color': 1,
'mass': 'MZ',
'width': 'WZ',
'texname': 'Z',
'antitexname': 'Z',
'line': 'wavy',
'charge': 0.,
'pdg_code': 23,
'propagating': True,
'is_part': True,
'self_antipart': True
}))
z = mypartlist[len(mypartlist) - 1]
# Gluon couplings to quarks
myinterlist.append(base_objects.Interaction({
'id': 1,
'particles': base_objects.ParticleList(\
[antiu, \
u, \
g]),
'color': [color.ColorString([color.T(2, 1, 0)])],
'lorentz':['FFV1'],
'couplings':{(0, 0):'GC_10'},
'orders':{'QCD':1}}))
# Gamma couplings to quarks
myinterlist.append(base_objects.Interaction({
'id': 2,
'particles': base_objects.ParticleList(\
[antiu, \
u, \
z]),
'color': [color.ColorString([color.T(1, 0)])],
'lorentz':['FFV2', 'FFV5'],
'couplings':{(0,0): 'GC_35', (0,1): 'GC_47'},
'orders':{'QED':1}}))
self.mymodel.set('particles', mypartlist)
self.mymodel.set('interactions', myinterlist)
self.mymodel.set('name', 'sm')
self.mypythonmodel = helas_call_writers.PythonUFOHelasCallWriter(
self.mymodel)
myleglist = base_objects.LegList()
myleglist.append(base_objects.Leg({'id': 2, 'state': False}))
myleglist.append(base_objects.Leg({'id': -2, 'state': False}))
myleglist.append(base_objects.Leg({'id': 2, 'state': True}))
myleglist.append(base_objects.Leg({'id': -2, 'state': True}))
myproc = base_objects.Process({
'legs': myleglist,
'model': self.mymodel
})
myamplitude = diagram_generation.Amplitude({'process': myproc})
self.mymatrixelement = helas_objects.HelasMultiProcess(myamplitude)
myleglist = base_objects.LegList()
myleglist.append(
base_objects.Leg({
'id': 4,
'state': False,
'number': 1
}))
myleglist.append(
base_objects.Leg({
'id': -4,
'state': False,
'number': 2
}))
myleglist.append(
base_objects.Leg({
'id': 4,
'state': True,
'number': 3
}))
myleglist.append(
base_objects.Leg({
'id': -4,
'state': True,
'number': 4
}))
myproc = base_objects.Process({
'legs': myleglist,
'model': self.mymodel
})
self.mymatrixelement.get('matrix_elements')[0].\
get('processes').append(myproc)
self.exporter = export_python.ProcessExporterPython(\
self.mymatrixelement, self.mypythonmodel)
def test_color_flow_string(self):
"""Test the color flow decomposition of various color strings"""
# qq~>qq~
my_cs = color.ColorString([color.T(-1000, 1, 2), color.T(-1000, 3, 4)])
goal_cs = color.ColorString([color.T(1, 4), color.T(3, 2)])
goal_cs.coeff = fractions.Fraction(1, 2)
self.assertEqual(color_amp.ColorBasis.get_color_flow_string(my_cs, []),
goal_cs)
# qq~>qq~g
my_cs = color.ColorString(
[color.T(-1000, 1, 2),
color.T(-1000, 3, 4),
color.T(5, 4, 6)])
goal_cs = color.ColorString(
[color.T(1, 2005),
color.T(3, 2), color.T(1005, 6)])
goal_cs.coeff = fractions.Fraction(1, 4)
self.assertEqual(
color_amp.ColorBasis.get_color_flow_string(my_cs,
[(8, 5, 1005, 2005)]),
goal_cs)
# gg>gg
my_cs = color.ColorString(
[color.Tr(-1000, 1, 2),
color.Tr(-1000, 3, 4)])
goal_cs = color.ColorString([
color.T(1001, 2002),
color.T(1002, 2003),
color.T(1003, 2004),
color.T(1004, 2001)
])
goal_cs.coeff = fractions.Fraction(1, 32)
self.assertEqual(
color_amp.ColorBasis.get_color_flow_string(my_cs,
[(8, 1, 1001, 2001),
(8, 2, 1002, 2002),
(8, 3, 1003, 2003),
(8, 4, 1004, 2004)]),
goal_cs)
def read_interactions_v4(fsock, ref_part_list):
"""Read a list of interactions from stream fsock, using the old v4 format.
Requires a ParticleList object as an input to recognize particle names."""
logger.info('load interactions')
myinterlist = InteractionList()
if not isinstance(ref_part_list, ParticleList):
raise ValueError, \
"Object %s is not a valid ParticleList" % repr(ref_part_list)
for line in fsock:
myinter = Interaction()
line = line.split("#", 2)[0] # remove any comment
line = line.strip() # makes the string clean
if line != "": # skip blank
values = line.split()
part_list = ParticleList()
try:
for str_name in values:
curr_part = ref_part_list.get_copy(str_name.lower())
if isinstance(curr_part, Particle):
# Look at the total number of strings, stop if
# anyway not enough, required if a variable name
# corresponds to a particle! (eg G)
if len(values) >= 2 * len(part_list) + 1:
part_list.append(curr_part)
else:
break
# also stops if string does not correspond to
# a particle name
else:
break
if len(part_list) < 3:
raise Interaction.PhysicsObjectError, \
"Vertex with less than 3 known particles found."
# Flip part/antipart of first part for FFV, FFS, FFT vertices
# according to v4 convention
spin_array = [part['spin'] for part in part_list]
if spin_array[:2] == [2, 2] and \
not part_list[0].get('self_antipart'):
part_list[0]['is_part'] = not part_list[0]['is_part']
myinter.set('particles', part_list)
# Give color structure
# Order particles according to color
# Don't consider singlets
color_parts = sorted(enumerate(part_list), lambda p1, p2:\
p1[1].get_color() - p2[1].get_color())
color_ind = [(i, part.get_color()) for i, part in \
color_parts if part.get_color() !=1]
colors = [c for i, c in color_ind]
ind = [i for i, c in color_ind]
# Set color empty by default
myinter.set('color', [])
if not colors:
# All color singlets - set empty
pass
elif colors == [-3, 3]:
# triplet-triplet-singlet coupling
myinter.set('color', [color.ColorString(\
[color.T(ind[1], ind[0])])])
elif colors == [8, 8]:
# octet-octet-singlet coupling
my_cs = color.ColorString(\
[color.Tr(ind[0], ind[1])])
my_cs.coeff = fractions.Fraction(2)
myinter.set('color', [my_cs])
elif colors == [-3, 3, 8]:
# triplet-triplet-octet coupling
myinter.set('color', [color.ColorString(\
[color.T(ind[2], ind[1], ind[0])])])
elif colors == [8, 8, 8]:
# Triple glue coupling
my_color_string = color.ColorString(\
[color.f(ind[0], ind[1], ind[2])])
my_color_string.is_imaginary = True
myinter.set('color', [my_color_string])
elif colors == [-3, 3, 8, 8]:
my_cs1 = color.ColorString(\
[color.T(ind[2], ind[3], ind[1], ind[0])])
my_cs2 = color.ColorString(\
[color.T(ind[3], ind[2], ind[1], ind[0])])
myinter.set('color', [my_cs1, my_cs2])
elif colors == [8, 8, 8, 8]:
# 4-glue coupling
cs1 = color.ColorString(
[color.f(0, 1, -1),
color.f(2, 3, -1)])
#cs1.coeff = fractions.Fraction(-1)
cs2 = color.ColorString(
[color.f(2, 0, -1),
color.f(1, 3, -1)])
#cs2.coeff = fractions.Fraction(-1)
cs3 = color.ColorString(
[color.f(1, 2, -1),
color.f(0, 3, -1)])
#cs3.coeff = fractions.Fraction(-1)
myinter.set('color', [cs1, cs2, cs3])
# The following line are expected to be correct but not physical validations
# have been performed. So we keep it commented for the moment.
# elif colors == [3, 3, 3]:
# my_color_string = color.ColorString(\
# [color.Epsilon(ind[0], ind[1], ind[2])])
# myinter.set('color', [my_color_string])
# elif colors == [-3, -3, -3]:
# my_color_string = color.ColorString(\
# [color.EpsilonBar(ind[0], ind[1], ind[2])])
# myinter.set('color', [my_color_string])
else:
logger.warning(\
"Color combination %s not yet implemented." % \
repr(colors))
# Set the Lorentz structure. Default for 3-particle
# vertices is empty string, for 4-particle pair of
# empty strings
myinter.set('lorentz', [''])
pdg_codes = sorted([part.get_pdg_code() for part in part_list])
# WWWW and WWVV
if pdg_codes == [-24, -24, 24, 24]:
myinter.set('lorentz', ['WWWW'])
elif spin_array == [3, 3, 3, 3] and \
24 in pdg_codes and - 24 in pdg_codes:
myinter.set('lorentz', ['WWVV'])
# gggg
if pdg_codes == [21, 21, 21, 21]:
myinter.set('lorentz', ['gggg1', 'gggg2', 'gggg3'])
# go-go-g
# Using the special fvigox routine provides the minus
# sign necessary for octet Majorana-vector interactions
if spin_array == [2, 2, 3] and colors == [8, 8, 8] and \
part_list[0].get('self_antipart') and \
part_list[1].get('self_antipart'):
myinter.set('lorentz', ['go'])
# If extra flag, add this to Lorentz
if len(values) > 3 * len(part_list) - 4:
myinter.get('lorentz')[0] = \
myinter.get('lorentz')[0]\
+ values[3 * len(part_list) - 4].upper()
# Use the other strings to fill variable names and tags
# Couplings: special treatment for 4-vertices, where MG4 used
# two couplings, while MG5 only uses one (with the exception
# of the 4g vertex, which needs special treatment)
# DUM0 and DUM1 are used as placeholders by FR, corresponds to 1
if len(part_list) == 3 or \
values[len(part_list) + 1] in ['DUM', 'DUM0', 'DUM1']:
# We can just use the first coupling, since the second
# is a dummy
myinter.set('couplings', {(0, 0): values[len(part_list)]})
if myinter.get('lorentz')[0] == 'WWWWN':
# Should only use one Helas amplitude for electroweak
# 4-vector vertices with FR. I choose W3W3NX.
myinter.set('lorentz', ['WWVVN'])
elif values[len(part_list)] in ['DUM', 'DUM0', 'DUM1']:
# We can just use the second coupling, since the first
# is a dummy
myinter.set('couplings',
{(0, 0): values[len(part_list) + 1]})
elif pdg_codes == [21, 21, 21, 21]:
# gggg
myinter.set(
'couplings', {
(0, 0): values[len(part_list)],
(1, 1): values[len(part_list)],
(2, 2): values[len(part_list)]
})
elif myinter.get('lorentz')[0] == 'WWWW':
# Need special treatment of v4 SM WWWW couplings since
# MG5 can only have one coupling per Lorentz structure
myinter.set('couplings', {(0, 0):\
'sqrt(' +
values[len(part_list)] + \
'**2+' + \
values[len(part_list) + 1] + \
'**2)'})
else: #if myinter.get('lorentz')[0] == 'WWVV':
# Need special treatment of v4 SM WWVV couplings since
# MG5 can only have one coupling per Lorentz structure
myinter.set('couplings', {(0, 0):values[len(part_list)] + \
'*' + \
values[len(part_list) + 1]})
#raise Interaction.PhysicsObjectError, \
# "Only FR-style 4-vertices implemented."
# SPECIAL TREATMENT OF COLOR
# g g sq sq (two different color structures, same Lorentz)
if spin_array == [3, 3, 1, 1] and colors == [-3, 3, 8, 8]:
myinter.set(
'couplings', {
(0, 0): values[len(part_list)],
(1, 0): values[len(part_list)]
})
# Coupling orders - needs to be fixed
order_list = values[2 * len(part_list) - 2: \
3 * len(part_list) - 4]
def count_duplicates_in_list(dupedlist):
"""return a dictionary with key the element of dupeList and
with value the number of times that they are in this list"""
unique_set = set(item for item in dupedlist)
ret_dict = {}
for item in unique_set:
ret_dict[item] = dupedlist.count(item)
return ret_dict
myinter.set('orders', count_duplicates_in_list(order_list))
myinter.set('id', len(myinterlist) + 1)
myinterlist.append(myinter)
except Interaction.PhysicsObjectError, why:
logger.error("Interaction ignored: %s" % why)
def setUp(self):
# A gluon
self.mypartlist.append(
base_objects.Particle({
'name': 'g',
'antiname': 'g',
'spin': 3,
'color': 8,
'mass': 'zero',
'width': 'zero',
'texname': 'g',
'antitexname': 'g',
'line': 'curly',
'charge': 0.,
'pdg_code': 21,
'propagating': True,
'is_part': True,
'self_antipart': True
}))
# A quark U and its antiparticle
self.mypartlist.append(
base_objects.Particle({
'name': 'u',
'antiname': 'u~',
'spin': 2,
'color': 3,
'mass': 'zero',
'width': 'zero',
'texname': 'u',
'antitexname': '\bar u',
'line': 'straight',
'charge': 2. / 3.,
'pdg_code': 2,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
antiu = copy.copy(self.mypartlist[1])
antiu.set('is_part', False)
# A quark D and its antiparticle
self.mypartlist.append(
base_objects.Particle({
'name': 'd',
'antiname': 'd~',
'spin': 2,
'color': 3,
'mass': 'zero',
'width': 'zero',
'texname': 'u',
'antitexname': '\bar u',
'line': 'straight',
'charge': -1. / 3.,
'pdg_code': 1,
'propagating': True,
'is_part': True,
'self_antipart': False
}))
antid = copy.copy(self.mypartlist[2])
antid.set('is_part', False)
# 3 gluon vertiex
self.myinterlist.append(base_objects.Interaction({
'id': 1,
'particles': base_objects.ParticleList(\
[self.mypartlist[0]] * 3),
'color': [color.ColorString([color.f(0, 1, 2)])],
'lorentz':['L1'],
'couplings':{(0, 0):'G'},
'orders':{'QCD':1}}))
# 4 gluon vertex
self.myinterlist.append(base_objects.Interaction({
'id': 2,
'particles': base_objects.ParticleList(\
[self.mypartlist[0]] * 4),
'color': [color.ColorString([color.f(-1, 0, 2),
color.f(-1, 1, 3)]),
color.ColorString([color.f(-1, 0, 3),
color.f(-1, 1, 2)]),
color.ColorString([color.f(-1, 0, 1),
color.f(-1, 2, 3)])],
'lorentz':['L(p1,p2,p3)', 'L(p2,p3,p1)', 'L3'],
'couplings':{(0, 0):'G^2',
(1, 1):'G^2',
(2, 2):'G^2'},
'orders':{'QCD':2}}))
# Gluon couplings to up and down quarks
self.myinterlist.append(base_objects.Interaction({
'id': 3,
'particles': base_objects.ParticleList(\
[self.mypartlist[1], \
antiu, \
self.mypartlist[0]]),
'color': [color.ColorString([color.T(2, 0, 1)])],
'lorentz':['L1'],
'couplings':{(0, 0):'GQQ'},
'orders':{'QCD':1}}))
self.myinterlist.append(base_objects.Interaction({
'id': 4,
'particles': base_objects.ParticleList(\
[self.mypartlist[2], \
antid, \
self.mypartlist[0]]),
'color': [color.ColorString([color.T(2, 0, 1)])],
'lorentz':['L1'],
'couplings':{(0, 0):'GQQ'},
'orders':{'QCD':1}}))
self.mymodel.set('particles', self.mypartlist)
self.mymodel.set('interactions', self.myinterlist)