Related papers: Constraints on the $U(1)_{B-L}$ model from global …
In this work we perform a non-linear extension of the $U(1)_{\rm Y}$ sector of the Standard Model leading to novel quartic effective interactions between the neutral gauge bosons. We study the induced effects through high-energy processes…
We investigate the effects of extra neutral gauge bosons on the high $Q^2$ region of the $e^+p \to e^+ X$ cross section at $\sqrt{s}=300$ GeV. We found that the only models with electroweak strength coupling, typical of extended gauge…
We consider right-handed neutrino dark matter $N_1$ in local $U(1)_{L_\mu-L_\tau}$-extended Ma model. With the light $U(1)_{\mu-\tau}$ gauge boson ($m_{Z'} \sim {\cal O}(100)$ MeV) and small $U(1)_{\mu-\tau}$ gauge coupling ($g_{Z'}\sim…
We study in an effective operator approach how the effects of new physics from various scenarios that contain an extra $Z'$ neutral gauge boson or doubly charged scalars, can affect and thus be tested by the precision polarized M\o{}ller…
We construct d=4,N=1 orientifolds of Gepner models with just the chiral spectrum of the standard model. We consider all simple current modular invariants of c=9 tensor products of N=2 minimal models. For some very specific tensor…
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 consider experimental constraints in the MeV region in order to determine the parameter space for the $U(1)_X$ extension of the Standard Model, presented in the first part of our work. In particular, we focus on the model UV-completed by…
We extend the Standard Model gauge group by $U(1)_{L_e-L_\mu}$ and introduce two scalars, a doublet and a singlet, that are charged under this new group and have lepton flavour violating couplings. Since in this model $\mu \to e$ processes…
We calculate the effects of a light, very weakly-coupled boson $X$ arising from a spontaneously broken $U(1)_{B-L}$ symmetry on $\Delta N_{\rm eff}$ as measured by the CMB and $Y_p$ from BBN. Our focus is the mass range $1 \; {\rm eV}…
We analyze various models with an extra U(1) gauge symmetry in addition to the Standard Model (SM) gauge group at low energies, and impose limits on the mass of the neutral Z' boson, M_Z', predicted in all such models, and on the Z-Z'…
A general electroweak scale $Z'$ is applied in a supersymmetric SU(6)$\timesSU(2)_h$ grand unification model, to have a $\Z_6$ for the hexality. We briefly show that there cannot exist any baryonic U(1)$'_B$ in any subgroup of E$_6$. Any…
The $W$ boson mass recently reported by the CDF collaboration shows a deviation from the standard model prediction with an excess at $7\sigma$ level. We investigate two simple extensions of the standard model with an extra $U(1)$ dark…
Several constructions, of stringy origins or not, generate abelian gauge extensions of the Standard Model (SM). Even if the particles of the SM are not charged under this extra $U'(1)$, one cannot avoid the presence of a kinetic mixing…
The $Z_{2}$-symmetric version of the Georgi-Machacek model does not possess a decoupling limit in which all the new particles can be made arbitrarily heavy, opening the possibility that the model can be entirely excluded if experiments…
A U(1)' or Z' is generic in many scenarios of physics beyond the Standard Model, such as string theory compactifications, GUTs, extra-dimensions, compositeness, dynamical electroweak symmetry breaking, dark-sector models, etc. We study the…
The conventional method using low energy theorems [3] does not seem to lead to an explicit unitarity limit in the scattering processes of longitudinally polarized gauge bosons for the high energy case in the extra U(1) superstring inspired…
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…
A search for a new $Z'$ gauge boson associated with (un)broken B-L symmetry in the keV-GeV mass range is carried out for the first time using the missing-energy technique in the NA64 experiment at the CERN SPS. From the analysis of the data…
We present the results of a calculation of deep inelastic electron-photon scattering at a linear collider for very high virtuality of the intermediate gauge boson up to NLO in perturbative QCD. The real photon is produced unpolarized via…
The existence of a new force beyond the Standard Model is compelling because it could explain several striking astrophysical observations which fail standard interpretations. We searched for the light vector mediator of this dark force, the…