NLOX is a computer program for calculations in high-energy particle physics. It provides fully renormalized scattering matrix elements in the Standard Model of particle physics, up to one-loop accuracy for all possible coupling-power combinations in the strong and electroweak couplings, and for processes with up to six external particles. PROGRAM SUMMARYProgram Title: NLOX Licensing provisions: CC BY NC 3.0 Programming language: C++. Fortran interface available, and Fortran compiler required for dependencies. Required External Dependencies: QCDLoop 1.95, OneLOop 3.6 (available for download in utility tarball).NLOX provides fully renormalized QCD and EW one-loop corrections to SM processes at the squared-amplitude level, for all the possible QCD and EW mixed coupling-power combinations to a certain parton-level process up to one-loop accuracy, including the full mass dependence on initialand final-state particle masses. 5 Based on a Feynman-diagram approach, with optimized parsing and storing of recurrent building blocks,NLOX has been developed with the intent of providing oneloop QCD and EW corrections in the SM, while maintaining the flexibility to be further extended.The generation and evaluation of one-loop QCD and EW corrections of a large variety of 2 → 3 and 2 → 4 SM processes has been thoroughly tested and, with this paper, we are releasing a description of the code functionalities, archives of pre-generated process code, and the core code to evaluate and interface to the pre-generated process code.The conventions used in building renormalized one-loop QCD and EW amplitudes with NLOX are summarized in Sec. 2, while the NLOX workflow and code generation is briefly illustrated in Sec. 3. The TRed tensor-reduction library, an essential part of the NLOX package, is described in Sec. 4. Sec. 5 provides some practical instructions on how to download, install, and use the current public version of NLOX. Finally, in Sec. 6 we report benchmark results for selected processes. A brief summary is provided in Sec. 7. In the two appendices we collect more details about renormalization and tensor reduction in NLOX.

After a brief introduction to the state of the art of theoretical predictions for electroweak vectorboson production with both top and bottom quarks at the LHC, we review the case of Z-boson production with b jets, and discuss the impact of NLO QCD+EW corrections and finite b-mass effects on the theoretical prediction for Z + b jet production.