Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Add N3LO ren SV #145

Merged
merged 3 commits into from
Dec 14, 2023
Merged
Changes from 2 commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
32 changes: 24 additions & 8 deletions src/pineko/scale_variations.py
Original file line number Diff line number Diff line change
Expand Up @@ -51,16 +51,32 @@ def ren_sv_coeffs(m, max_as, logpart, which_part, nf):
float
renormalization scale variation contribution
"""
bcoeff = beta.beta_qcd((max_as - logpart - which_part + 2, 0), nf)
as_normalization = AS_NORM ** (max_as - which_part)
# nothing to do?
if max_as == 0:
return 0.0
if max_as == 2:
if which_part > 0:
m += 1
elif logpart > 1:
m = 0.5 * m * (m + 1)
return m * as_normalization * bcoeff
# eko uses as = alpha_s/(4pi), but pineappl just alpha_s
as_normalization = AS_NORM ** (max_as - which_part)
# the coefficients can be found in the NNLO MHOU paper
# (which also contains a generating MMa script)
beta0 = beta.beta_qcd_as2(nf)
beta1 = beta.beta_qcd_as3(nf)
beta2 = beta.beta_qcd_as4(nf)
ren_coeffs = {
# NLO
(1, 1, 0): m * beta0,
# NNLO
(2, 1, 1): (m + 1) * beta0,
(2, 1, 0): (m + 0) * beta1,
(2, 2, 0): m * (m + 1) / 2.0 * beta0**2,
# N3LO
(3, 1, 2): (m + 2) * beta0,
(3, 1, 1): (m + 1) * beta1,
(3, 1, 0): (m + 0) * beta2,
(3, 2, 1): (m + 1) * (m + 2) / 2.0 * beta0**2,
(3, 2, 0): m * (2 * m + 3) / 2.0 * beta0 * beta1,
(3, 3, 0): m * (m + 1) * (m + 2) / 6 * beta0**3,
}
return as_normalization * ren_coeffs[(max_as, logpart, which_part)]


def requirements(m: int, max_as: int, al: int) -> Dict[OrderTuple, List[OrderTuple]]:
Expand Down
Loading