| PDF family | Maximal number of flavors | order of alpha_s evo. | alpha_s is set to.. |
|---|---|---|---|
| CT18(AXZ) NF3 NNLO | 3 | 3 | 0.1056 at Q=m_Z |
| CT18(AXZ) NF4 NNLO | 4 | 3 | 0.1130 at Q=m_Z |
| CT18(AXZ) NF6 NNLO | 6 | 3 | 0.1180 at Q=m_Z |
| CT18(AXZ) NF3 NLO | 3 | 2 | 0.1060 at Q=m_Z |
| CT18(AXZ) NF4 NLO | 4 | 2 | 0.1128 at Q=m_Z |
| CT18(AXZ) NF6 NLO | 6 | 2 | 0.1180 at Q=m_Z |