"""QCD anomalous dimensions.
Note:
Functions in this module have as first argument Mellin moment
n=j+1, where j is conformal moment used everywhere else.
Thus, they should always be called as f(j+1, ...).
"""
# from cmath import exp
# from scipy.special import loggamma as clngamma
import numpy as np
from .constants import CA, CF, CG, TF
from .special import (S1, S2, S3, MellinF2, S2_prime, S2_tilde, S3_prime, poch,
psi, zeta)
[docs]def non_singlet_LO(n: complex, nf: int, prty: int = 1) -> complex:
"""Non-singlet LO anomalous dimension.
Args:
n (complex): which moment (= Mellin moment for integer n)
nf (int): number of active quark flavors
prty (int): 1 for NS^{+}, -1 for NS^{-}, irrelevant at LO
Returns:
Non-singlet LO anomalous dimension.
"""
return CF*(-3.0-2.0/(n*(1.0+n))+4.0*S1(n))
[docs]def singlet_LO(n: complex, nf: int, prty: int = 1) -> np.ndarray:
"""Singlet LO anomalous dimensions.
Args:
n (complex): which moment (= Mellin moment for integer n)
nf (int): number of active quark flavors
prty (int): C parity, irrelevant at LO
Returns:
2x2 complex matrix ((QQ, QG),
(GQ, GG))
"""
qq0 = CF*(-3.0-2.0/(n*(1.0+n))+4.0*S1(n))
qg0 = (-4.0*nf*TF*(2.0+n+n*n))/(n*(1.0+n)*(2.0+n))
gq0 = (-2.0*CF*(2.0+n+n*n))/((-1.0+n)*n*(1.0+n))
gg0 = (-22*CA/3.-8.0*CA*(1/((-1.0+n)*n)+1/((1.0+n)*(2.0+n))-S1(n))+8*nf*TF/3.)/2.
return np.array([[qq0, qg0],
[gq0, gg0]])
[docs]def non_singlet_NLO(n: complex, nf: int, prty: int) -> complex:
"""Non-singlet anomalous dimension.
Args:
n (complex): which moment (= Mellin moment for integer n)
nf (int): number of active quark flavors
prty (int): 1 for NS^{+}, -1 for NS^{-}
Returns:
Non-singlet NLO anomalous dimension.
"""
# From Curci et al.
nlo = (CF * CG * (
16*S1(n)*(2*n+1)/poch(n, 2)**2 +
16*(2*S1(n) - 1/poch(n, 2)) * (S2(n)-S2_prime(n/2, prty)) +
64 * S2_tilde(n, prty) + 24*S2(n) - 3 - 8*S3_prime(n/2, prty) -
8*(3*n**3 + n**2 - 1)/poch(n, 2)**3 -
16*prty*(2*n**2 + 2*n + 1)/poch(n, 2)**3) +
CF * CA * (S1(n)*(536/9 + 8*(2*n+1)/poch(n, 2)**2) - 16*S1(n)*S2(n) +
S2(n)*(-52/3 + 8/poch(n, 2)) - 43/6 -
4*(151*n**4 + 263*n**3 + 97*n**2 + 3*n + 9)/9/poch(n, 2)**3) +
CF * nf * TF * (-(160/9)*S1(n) + (32/3)*S2(n) + 4/3 +
16*(11*n**2 + 5*n - 3)/9/poch(n, 2)**2)) / 4
return nlo
[docs]def singlet_NLO(n: complex, nf: int, prty: int = 1) -> np.ndarray:
"""Singlet NLO anomalous dimensions matrix.
Args:
n (complex): which moment (= Mellin moment for integer n)
nf (int): number of active quark flavors
prty (int): C parity
Returns:
Matrix (LO, NLO) where each is in turn
2x2 complex matrix
((QQ, QG),
(GQ, GG))
"""
qq1 = non_singlet_NLO(n, nf, 1) - 4*CF*TF*nf*(
5*n**5+32*n**4+49*n**3+38*n**2 +
28*n+8)/((n-1)*n**3*(n+1)**3*(n+2)**2)
qg1 = (-8*CF*nf*TF*(
(-4*S1(n))/n**2+(4+8*n + 26*n**3 + 11*n**4 +
15*(n*n))/(n**3*(1+n)**3*(2+n)) +
((2+n+n*n)*(5-2*S2(n) + 2*(S1(n)*S1(n))))/(n*(1+n)*(2+n))) -
8*CA*nf*TF*((8*(3+2*n)*S1(n))/((1+n)**2*(2+n)**2) +
(2*(16+64*n+128*n**3+85*n**4+36*n**5+25*n**6 +
15*n**7+6*n**8+n**9+104*(n*n)))/(
(-1+n)*n**3*(1+n)**3*(2+n)**3)+(
(2+n+n*n)*(2*S2(n)-2*(S1(n)*S1(n))-2*S2(n/2)))/(n*(1+n)*(2+n))))/4
gq1 = (-(32/3)*CF*nf*TF*((1+n)**(-2) +
((-(8/3)+S1(n))*(2+n+n*n))/((-1+n)*n*(1+n))) -
4*(CF*CF)*((-4*S1(n))/(1+n)**2-(
-4-12*n+28*n**3+43*n**4 +
30*n**5+12*n**6-n*n)/((-1+n)*n**3*(1+n)**3) +
((2+n+n*n)*(10*S1(n)-2*S2(n)-2*(S1(n)*S1(n))))/((-1+n)*n*(1+n))) -
8*CF*CA*(((1/9)*(144+432*n-1304*n**3-1031*n**4 +
695*n**5+1678*n**6+1400*n**7+621*n**8+109*n**9 -
152*(n*n)))/((-1+n)**2*n**3*(1+n)**3*(2+n)**2) -
((1/3)*S1(n)*(-12-22*n+17*n**4 +
41*(n*n)))/((-1+n)**2*n**2*(1+n))+(
(2+n+n*n)*(S2(n) + S1(n)*S1(n)-S2(n/2)))/((-1+n)*n*(1+n))))/4
gg1 = (
CF*nf*TF*(8+(16*(-4-4*n-10*n**3+n**4+4*n**5+2*n**6 -
5*(n*n)))/((-1+n)*n**3*(1+n)**3*(2+n))) +
CA*nf*TF*(32/3 - (160/9)*S1(n)+(
(16/9)*(12+56*n+76*n**3+38*n**4+94*(n*n)))/((-1+n)*n**2*(1+n)**2*(2+n))) +
CA*CA*(-64/3+(536/9)*S1(n)+(64*S1(n)*(
-2-2*n+8*n**3+5*n**4+2*n**5+7*(n*n)))/((-1+n)**2*n**2*(1+n)**2*(2+n)**2) -
((4/9)*(576+1488*n-1632*n**3-2344*n**4+1567*n**5 +
6098*n**6+6040*n**7+2742*n**8+457*n**9+560*(n*n)))/(
(-1+n)**2*n**3*(1+n)**3*(2+n)**3) -
16*S1(n)*S2(n/2)+(32*(1+n+n*n)*S2(n/2))/(
(-1+n)*n*(1+n)*(2+n))-4*S3(n/2) +
32*(S1(n)/n**2-(5/8)*zeta(3)+MellinF2(n) -
zeta(2)*(-psi(n/2)+psi((1+n)/2))/2)))/4
return np.array([[qq1, qg1],
[gq1, gg1]])
[docs]def block(n: complex, nf: int) -> np.ndarray:
"""LO+NLO block anomalous dimensions matrix.
Args:
n (complex): which moment (= Mellin moment for integer n)
nf (int): number of active quark flavors
Returns:
block[k, p, i, j]
- k is index if n is array, otherwise 0
- p is pQCD order (0=LO, 1=NLO)
- i, j in [Q, G, NS+, NS-], forming
4x4 complex matrix
((QQ, QG, 0, 0),
(GQ, GG, 0, 0),
( 0, 0, NS+, 0),
( 0, 0, 0, NS-))
"""
lo_SI = np.atleast_3d(singlet_LO(n, nf)).transpose((2, 0, 1))
lo_NS = np.atleast_3d(non_singlet_LO(n, nf)).transpose((1, 2, 0))
nlo_SI = np.atleast_3d(singlet_NLO(n, nf)).transpose((2, 0, 1))
nlo_plus_NS = np.atleast_3d(non_singlet_NLO(n, nf, prty=1)).transpose((1, 2, 0))
nlo_minus_NS = np.atleast_3d(non_singlet_NLO(n, nf, prty=-1)).transpose((1, 2, 0))
zero_SI = np.zeros_like(lo_SI)
zero_NS = np.zeros_like(lo_NS)
lo_NS_block = np.block([[lo_NS, zero_NS],
[zero_NS, lo_NS]])
lo_block = np.block([[lo_SI, zero_SI],
[zero_SI, lo_NS_block]])
nlo_NS_block = np.block([[nlo_plus_NS, zero_NS],
[zero_NS, nlo_minus_NS]])
nlo_block = np.block([[nlo_SI, zero_SI],
[zero_SI, nlo_NS_block]])
return np.stack([lo_block, nlo_block], axis=1)