Related papers: An Effective Z'
A broad class of supersymmetric extensions of the standard model predict a Z' vector boson whose mass is naturally in the range 250 GeV < M_Z' < 2 TeV. To avoid unacceptably large mixing with the Z, one requires either a discrete tuning of…
The Dark Abelian Sector Model (DASM) is an extension of the Standard Model of particle physics with an additional spontaneously broken $U_\text{d}(1)$ gauge symmetry connected to a dark sector, i.e. the SM particles do not carry the…
We consider models with extra U(1)' gauge symmetry that is broken spontaneously. In the models, there are cold dark matter candidates which are charged under U(1)' symmetry. Depending on the charge assignment, we can evade the strong bound…
We study all possible $U(1)$-extensions of the standard model (SM) in the framework of noncommutative geometry (NCG) with the algebra $\hhh\op\cc\op\cc\op M_3(\cc)$. Comparison to experimental data about the mass of a hypothetical $Z'$…
The CDF collaboration has set lower limits on the masses of the Z' bosons occurring in a range of E_6 GUT based models. We revisit their analysis and extend it to certain other E_6 scenarios as well as to some general classes of models…
We study minimal benchmark models of dark matter with an extra anomaly-free U(1)' gauge boson Z'. We find model parameters that give rise to the correct cosmological dark matter density while evading the latest direct detection searches for…
In models with a U(1) gauge extension beyond the Standard Model, one can derive sum rules for the couplings of the theory that are a consequence of tree-level unitarity. In this paper, we provide a comprehensive list of coupling sum rules…
We present new anomaly free gauge models where the gauge field only has axial vector couplings to both quarks and leptons. We use the left-right symmetric universal seesaw models as the basis for this construction with an extra $U(1)_a$ as…
Many extension of the standard model contain an extra U(1)' gauge group with a heavy Z' gauge boson. Perhaps the most clear signal for such a Z' would be a resonance in the invariant mass spectrum of the lepton pairs to which it decays. In…
Whilst the prospect of new $Z'$ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by…
Models with a light, additional gauge boson are attractive extensions of the standard model. Often these models are only considered as effective low energy theory without any assumption about an UV completion. This leaves not only the…
In many extensions of the Standard Model the presence of an extra neutral boson, Z', is invoked. A precision study of weak neutral-current exchange processes involving only second generation fermions is still missing. We propose a search…
We explore a scenario where Dark Matter (DM) couples to the Standard Model mainly via a scalar mediator ${\cal S}$ that is odd under a $Z_2$ symmetry, leading to interesting collider signatures. In fact, if linear interactions with the…
We study electroweak scale Dark Matter (DM) whose interactions with baryonic matter are mediated by a heavy anomalous $Z'$. We emphasize that when the DM is a Majorana particle, its low-velocity annihilations are dominated by loop…
A model of dark matter (DM) that communicates with the Standard Model (SM) exclusively through suppressed dimension five operator is discussed. The SM is augmented with a symmetry $U(1)_X \otimes Z_2$, where $U(1)_X$ is gauged and broken…
We consider extending the Standard Model by an anomaly-free and possibly flavour non-universal $U(1)_X$ gauge symmetry, whose breaking gives a $Z^\prime$ boson that does not affect electroweak precision observables at tree-level or via…
We consider the physics of an extra $U(1)$ gauge boson $Z'$, which can mix with $Z$ through intermediate fermion loops. The loop contribution due to the heavy top quark significantly affects the low-energy observables, and for $m_{Z'}>m_Z$,…
Searching for heavy neutral gauge bosons Z', predicted in extensions of the Standard Model based on a U(1)' gauge symmetry, is one of the challenging objectives of the experiments carried out at the Large Hadron Collider. In this paper, we…
We present a formalism for new $U(1)$ interactions involving weak hypercharge, baryon, and lepton numbers, and a possible axial symmetry generator $F_A$ in the presence of a second Brout-Englert-Higgs doublet. The resulting $U$ boson, after…
We perform a systematic analysis of Standard Model extensions with an additional anomaly-free gauge $U(1)$ symmetry, to generate tree-level Dirac neutrino masses. An anomaly-free symmetry demands nontrivial conditions on the charges of the…