,full t-channel mb=0

This calculation is based on ref. [1]. This process constitutes the real correction needed for the complete NNLO order calculation. In other words it is the plus-one-jet process evaluated at NLO.

The processes 164 and 169 represent off-shell single-top-quark and anti-top-quark production, respectively. The calculations are performed in the complex-mass scheme. Both the SM and contributions from the SMEFT can be calculated. For more details on this calculation, please refer to ref. [2].

Dynamical double deep inelastic scattering scales can be consistently used at
NLO by setting dynamicscale to ‘DDIS’ and scale=facscale to 1d0. In this way
the momentum transfer along the W-boson Q^{2} is used as the scale for the
light-quark-line corrections μ^{2} = Q^{2}, and μ^{2} = Q^{2} + m_{t}^{2} for the heavy-quark-line
corrections. These scales are also consistently used for the non-resonant
contributions, with QCD corrections on the ud-quark line, and separate QCD
corrections on the bottom-quark line.

The new block ‘Single top SMEFT, nproc=164,169’ in the input file governs the
inclusion of SMEFT operators and corresponding orders. The scale of new physics Λ
can be separately set, and has a default value of 1000 GeV. The flag enable
1/lambda4 enables the 1∕Λ^{4} contributions, where operators 33φud,33dW,33dG and
4R can contribute for the first time. For the non-Hermitian operators we allow
complex Wilson coefficients. We also have a flag to disable the pure SM contribution,
leaving only contributions from SMEFT operators either interfered with the SM
amplitudes or as squared contributions at 1∕Λ^{4}. This can be used to directly and
quickly extract kinematical distributions and the magnitudes of pure SMEFT
contributions.

To allow for easier comparisons with previous anomalous couplings results, and possibly estimate further higher order effects, we allow for an anomalous couplings mode at LO by enabling the corresponding flag. The relations between our operators and the anomalous couplings are

δV _{L} | = (3,33)
φq , where V _{L} = 1 + δV _{L} , | ||

V _{R} | = 33
φud^{*} , | ||

g_{L} | = -4 ⋅33 dW , | ||

g_{R} | = -4 ⋅33
uW^{*}, |

where m_{W} is the W-boson mass, and m_{W} = g_{W}v has been used to derive this
equivalence. Note that the minus sign for g_{L} and g_{R} is different from the literature.
See also the publication [2] for more information.

For comparisons with on-shell results one needs to add up the contributions from processes 161 at NLO and from the virt and real contributions from 162, see above.

The analysis/plotting routine is contained in the file ‘src/User/nplotter_ktopanom.f’, where all observables presented in this study are implemented, and the W-boson/neutrino reconstruction is implemented and can be switched on or off.

nplotter_ktopanom.f is the default plotting routine.

[1] J. Campbell, T. Neumann and Z. Sullivan, Single-top-quark production in the t-channel at NNLO, JHEP 02 (2021) 040 [2012.01574].

[2] T. Neumann and Z.E. Sullivan, Off-Shell Single-Top-Quark Production in the Standard Model Effective Field Theory, JHEP 06 (2019) 022 [1903.11023].