New physics contributions to the muon anomalous magnetic moment: A numerical code

We consider the contributions of individual new particles to the anomalous magnetic moment of the muon, utilizing the generic framework of simplified models. We also present analytic results for all possible one-loop contributions, allowing easy application of these results for more complete models which predict more than one particle capable of correcting the muon magnetic moment. Additionally, we provide a mathematica code to allow the reader to straightforwardly compute any one-loop contribution. Furthermore, we derive bounds on each new particle considered, assuming either the absence of other significant contributions to a_ or that the anomaly has been resolved by some other mechanism. The simplified models we consider are constructed without the requirement of SU (2) ₋ invariance, but appropriate chiral coupling choices are also considered. In summary, we found the following particles capable of explaining the current discrepancy, assuming unit couplings: 2 TeV (0. 3 TeV) neutral scalar with pure scalar (chiral) couplings, 4 TeV doubly charged scalar with pure pseudoscalar coupling, 0. 3--1 TeV neutral vector boson depending on what couplings are used (vector, axial, or mixed), 0. 5--1 TeV singly charged vector boson depending on which couplings are chosen, and 3 TeV doubly charged vector-coupled bosons. We also derive the following 1 lower bounds on new particle masses assuming unit couplings and that the experimental anomaly has been otherwise resolved: a doubly charged pseudoscalar must be heavier than 7 TeV, a neutral scalar than 3 TeV, a vector-coupled new neutral boson 600 GeV, an axial-coupled neutral boson 1. 5 TeV, a singly charged vector-coupled W^' 1 TeV, a doubly charged vector-coupled boson 5 TeV, scalar leptoquarks 10 TeV, and vector leptoquarks 10 TeV. We emphasize that the quoted numbers apply within simplified models, but the reader can easily use our mathematica code to calculate the contribution of their own model of new physics.