Several collaborations have recently performed lattice calculations aimed specifically at dark matter, including work with SU(2), SU(3), SU(4) and SO(4) gauge theories to represent the dark sector. Highlights of these studies are presented here, afte
r a reminder of how lattice calculations in QCD itself are helping with the hunt for dark matter.
Proposals for physics beyond the standard model often include new colored particles at or beyond the scale of electroweak symmetry breaking. Any new particle with a sufficient lifetime will bind with standard model gluons and quarks to form a spectru
m of new hadrons. Here we focus on colored particles in the octet, decuplet, 27-plet, 28-plet and 35-plet representations of SU(3) color because these can form hadrons without valence quarks. In every case, lattice creation operators are constructed for all angular momentum, parity and charge conjugation quantum numbers. Computations with fully-dynamical lattice QCD configurations produce numerical results for mass splittings within this new hadron spectrum. A previous quenched lattice study explored the octet case for certain quantum number choices, and our findings provide a reassessment of those early results.
The spectrum of energy levels is computed for all available angular momentum and parity quantum numbers in the SU(2)-Higgs model, with parameters chosen to match experimental data from the Higgs-W boson sector of the standard model. Several multi-bos
on states are observed, with and without linear momentum, and all are consistent with weakly-interacting Higgs and W bosons. The creation operators used in this study are gauge-invariant so, for example, the Higgs operator is quadratic rather than linear in the Lagrangians scalar field.
Radiative decays of bottomonium are revisited, focusing on contributions from higher-order relativistic effects. The leading relativistic correction to the magnetic spin-flip operator at the photon vertex is found to be particularly important. The co
mbination of O(v^6) effects in the nonrelativistic QCD action and in the transition operator moves previous lattice results for excited Upsilon decays into agreement with experiment.
