The dark Z′ portal: direct, indirect and collider searches

124

We study direct detection in simplified models of Dark Matter (DM) in which interactions with Standard Model (SM) fermions are mediated by a heavy vector boson. We consider fully general, gauge-invariant couplings between the SM, the mediator and both scalar and fermion DM. We account for the evolution of the couplings between the energy scale of the mediator mass and the nuclear energy scale. This running arises from virtual effects of SM particles and its inclusion is not optional. We compare bounds on the mediator mass from direct detection experiments with and without accounting for the running. In some cases the inclusion of these effects changes the bounds by several orders of magnitude, as a consequence of operator mixing which generates new interactions at low energy. We also highlight the importance of these effects when translating LHC limits on the mediator mass into bounds on the direct detection cross section. For an axial-vector mediator, the running can alter the derived bounds on the spin-dependent DM-nucleon cross section by a factor of two or more. Finally, we provide tools to facilitate the inclusion of these effects in future studies: general approximate expressions for the low energy couplings and a public code runDM to evolve the couplings between arbitrary energy scales.

Section: Simplified Models For Vector Mediatorsmentioning

confidence: 99%

You can hide but you have to run: direct detection with vector mediators

DʼEramo

Kavanagh

Panci

2016

124

“…It is important to first notice that the Z gauge boson arising from the L µ − L τ local symmetry dictates a dark matter phenomenology rather different from other realizations of a "dark Z portal" (see e.g. [67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84]). For example, the dark matter pair annihilation exclusively yields muon, tau, and neutrino pairs, as well as Z boson pairs, if kinematically allowed (i.e.…”

Section: Dark Matter Phenomenologymentioning

confidence: 99%

Explaining dark matter and B decay anomalies with an L μ − L τ model

Altmannshofer

Gori

Profumo

et al. 2016

Self Cite

185

118

We present a dark sector model based on gauging the L µ − L τ symmetry that addresses anomalies in b → sµ + µ − decays and that features a particle dark matter candidate. The dark matter particle candidate is a vector-like Dirac fermion coupled to the Z gauge boson of the L µ − L τ symmetry. We compute the dark matter thermal relic density, its pair-annihilation cross section, and the loop-suppressed dark matter-nucleon scattering cross section, and compare our predictions with current and future experimental results. We demonstrate that after taking into account bounds from B s meson oscillations, dark matter direct detection, and the CMB, the model is highly predictive: B physics anomalies and a viable particle dark matter candidate, with a mass of ∼ (5 − 23) GeV, can be accommodated only in a tightly-constrained region of parameter space, with sharp predictions for future experimental tests. The viable region of parameter space expands if the dark matter is allowed to have L µ − L τ charges that are smaller than those of the SM leptons.

“…[28][29][30][31][32][33][34][35][36][37][38][39][40], with collider signals for the Z ′ searched for at the Tevatron [28][29][30][31] and the LHC [29][30][31]. LHC collider signatures of a leptophobic Z ′ boson that couples to a dark matter candidate had been studied in refs.…”

Section: Jhep05(2014)106mentioning

confidence: 99%

“…LHC collider signatures of a leptophobic Z ′ boson that couples to a dark matter candidate had been studied in refs. [32,33]. In refs.…”

Section: Jhep05(2014)106mentioning

confidence: 99%

Phenomenology of E 6-inspired leptophobic Z ′ boson at the LHC

Chiang

Nomura²,

Yagyu³

2014

Abstract:We study collider phenomenology of a leptophobic Z ′ boson existing in eight scenarios of the E 6 grand unified theory, differing in particle embeddings. We first review the current bound on the Z ′ mass m Z ′ based upon the LHC data of pp → tt process at 8 TeV collisions with an integrated luminosity of 19.6 fb −1 . Most scenarios have a lower bound of about 1 TeV. However, this constraint does not apply to the case where m Z ′ < 2m t , and other methods need to be employed for this lower mass regime. Using existing UA2 constraints and dijet data at the LHC, we find that only one of the eight scenarios is excluded at 95% confidence level. No bound can be obtained from W jj and Zjj measurements. We propose to use the photon associated production of the Z ′ boson that subsequently decays into a pair of bottom quarks, pp → Z ′ γ → bbγ, at the LHC to explore the constraints in the lower mass regime. We compute the expected signal significance as a function of m Z ′ using detailed simulations of signal and irreducible background events. We find constraints for two more scenarios using the 8-TeV data and taking appropriate kinematical cuts. We also show the discovery reach for each scenario at the 14-TeV LHC machine.