Weak-triplet, color-octet scalars, and the CDF dijet excess

Abstract

We extend the standard model to include a weak-triplet and color-octet scalar. This ''octo-triplet'' field consists of three particles, two charged and one neutral, whose masses and renormalizable interactions depend only on two new parameters. The charged octo-triplet decay into a W boson and a gluon is suppressed by a loop factor and an accidental cancellation. Thus, the main decays of the charged octotriplet may occur through higher-dimensional operators, mediated by a heavy vectorlike fermion, into quark pairs. For an octo-triplet mass below the t " b threshold, the decay into Wb " b or Wb" s through an off shell top quark has a width comparable to that into c" s or c "b. Pair production with one octo-triplet decaying into two jets and the other decaying into a W and two soft b jets may explain the dijet-plus-W excess reported by the CDF Collaboration. Using a few kinematic distributions, we compare two mechanisms of octo-triplet pair production: through an s-channel coloron and through the coupling to gluons. The higherdimensional operators that allow dijet decays also lead to CP violation in B s À " B s mixing.

Top quark asymmetry and dijet resonances

“…Such models would naively be unconstrained by resonance searches (see refs. [19][20][21][22][23] for other approaches). In previous work [7,8], we pointed out the possibility that a gauge boson with flavor-changing u − t − V coupling could explain the A t F B asymmetry via the t-channel exchange of V .…”

NeutralB-meson mixing from three-flavor lattice quantum chromodynamics: Determination of theSU(3)-breaking ratioξ<

“…In addition, the theoretical calculation of BSM contributions to mixing and the experimental measurement of B 0 mixing parameters can help in constraining BSM parameters and understanding new physics [6]. Several recent studies have addressed that task [3][4][5][6][7][17][18][19][20][21][22][23][24], finding that one of the main limitations to further constraining the parameter space in BSM theories is the error associated with the theoretical calculation of the nonperturbative inputs.…”

Physics motivation for a pilot dark matter search at Jefferson Laboratory

“…In this appendix we generalize the results from [73] and compute the de-excitation decays in the inelastic scenario where a DM particle up scatters into a heavier darksector state and promptly de-excites to a three-body final state inside the detector. For scalar decays, the three-body amplitude for…”