31 f(-p1) + f(-p2) → Z(→ e-(p3) + e+(p4))

31.1 Z-boson production, processes 31–33

These processes represent the production of a Z boson which subsequently decays either into electrons (nproc=31), neutrinos (nproc=32) or bottom quarks (nproc=33). Where appropriate, the effect of a virtual photon is also included. As noted above, for nproc=31 and nproc=33 the constraint m34min > 0 is obligatory. The calculation may be performed at LO, NLO and NNLO [1, 2] although the NLO and NNLO calculation of process 33 does not include radiation from the bottom quarks (i.e. radiation occurs in the initial state only).

This process can be calculated at LO, NLO, and NNLO. NLO calculations can be performed by subtraction, zero-jettiness slicing and qT-slicing. NNLO calculations can be performed by zero-jettiness slicing and qT-slicing.

To calculate the total cross section to on-shell Z bosons, we take process (nproc=32), (no γ* contribution) and set (zerowidth=.true.) and (removebr =.true.). When removebr is true in process 31, the Z boson does not decay.

31.2 Input files for jet-vetoed cross-sections, ref. [3]

31.3 Input file for transverse momentum resummed cross-sections, ref. [4]

31.4 Physics of process 31

31.5 Plotter

nplotter_Z_only.f is the default plotting routine.

31.6 Example input and output file(s)

input31.ini process31.out

References

[1]    R. Boughezal, J.M. Campbell, R.K. Ellis, C. Focke, W. Giele, X. Liu et al., Color singlet production at NNLO in MCFM, Eur. Phys. J. C 77 (2017) 7 [1605.08011].

[2]    J.M. Campbell, R.K. Ellis and S. Seth, Non-local slicing approaches for NNLO QCD in MCFM, 2202.07738.

[3]    J.M. Campbell, R.K. Ellis, T. Neumann and S. Seth, Jet-veto resummation at N3LLp+NNLO in boson production processes, 2301.11768.

[4]    T. Becher and T. Neumann, Fiducial qT resummation of color-singlet processes at N3LL+NNLO, JHEP 03 (2021) 199 [2009.11437].