Related papers: Z' Reservation at LEP2
We revisit our previous model proposed in Ref. \cite{Okada:2013iba}, in which lepton masses except the tauon mass are generated at the one-loop level in a TeV scale physics. Although in the previous work, rather large Yukawa couplings…
We construct a model where the Yukawa couplings of the Standard Model (SM) fermions arise from the breaking of a $Z_2$ symmetry and through mixing with a fourth family of vector-like fermions. By adding a scalar leptoquark, which is an…
We investigate supersymmetric models where neither R-parity nor lepton number nor baryon number is imposed. The full high energy theory has an exact horizontal U(1) symmetry that is spontaneously broken. Quarks and Higgs fields carry…
In the context of a simplified leptophilic Dark Matter (DM) scenario where the mediator is a new charged fermion carrying leptonic quantum number and the DM candidate is either scalar or vector, the complementarity of different bounds is…
Neutrinos allow for a test of the hypothesis that the fermions of the Standard Model have Fermi-point splitting, analogous to the fermionic quasi-particles of certain condensed-matter systems. If present, the corresponding Lorentz-violating…
The general anomaly-free $U(1)'$ models allow non-universal lepton charges. We explore the sensitivities of FASER/FASER2, COHERENT and DUNE/T2HK precision experiments to the new gauge boson $Z'$ and the new CP-even scalar $\phi$. With…
We investigate a gauge extension of the Standard Model in light of the observed hints of lepton universality violation in $b \to c \ell \nu$ and $b \to s \ell^+ \ell^-$ decays at BaBar, Belle and LHCb. The model consists of an extended…
We investigate a model on an extra dimension $S^1$ where plenty of effective boundary points described by point interactions (zero-thickness branes) are arranged. After suitably selecting the conditions on these points for each type of…
The production of a charged lepton (e/mu) pair with a large missing energy at a linear collider is discussed as a means of distinguishing the minimal supersymmetry (MSSM) scenario from that with large extra dimensions (ADD) for parameter…
We explore the possibility that lepton family numbers and baryon number are such good symmetries of Nature because they are the global remnant of a spontaneously broken gauge symmetry. An almost arbitrary linear combination of these…
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…
This final analysis of hadronic and leptonic cross-sections and of leptonic forward-backward asymmetries in e+e- collisions with the OPAL detector makes use of the full LEP1 data sample comprising 161 pb^-1 of integrated luminosity and 4.5…
We present model independent constraints on the masses and couplings to fermions of $B$ and $L$ conserving leptoquarks. Such vector or scalar particles could have masses below 100 GeV and be produced at HERA; we list the generation…
Starting from a microscopic t-J like model and a SU(2) spin-charge separation ansatz, a relativistic continuum gauge lagrangian is obtained in the vicinity of a nodal point of the Fermi surface. The excitations in the pseudogap phase are…
We derive in a simple way the $(Z_2)^3$ symmetry which characterizes uniquely the phenomenologically successful tripartite form leading to the tribimaximal mixing in the neutrino mass matrix. We impose this symmetry in a setup including the…
Model-independent search for the Abelian Z' gauge boson in the Drell-Yan process at the LHC at s^{1/2}= 7 TeV and 8 TeV is fulfilled. Estimations of the Z' axial-vector coupling a_f^2 to the standard model fermions, the couplings of the…
We discuss the production, at high--energy e$^+$e$^-$ linear colliders, of new heavy fermions predicted by extensions of the Standard Model. We analyze in great details the various signals and the corresponding backgrounds for both pair…
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…
We study embedding of non-commuting $Z_2$ and $Z_m$, $m\geq 3$ symmetries in discrete subgroups (DSG) of $U(3)$ and analytically work out the mixing patterns implied by the assumption that $Z_2$ and $Z_m$ describe the residual symmetries of…
We consider lepton pair production at a hadron collider in a class of effective theories with the relevant operators being four-fermion contact interaction. Despite the nonrenormalizable nature of the interaction, we explicitly demonstrate…