Related papers: TeV-Scale Z' Bosons from D-branes
We present a supersymmetric model of fermion masses with SU(4)*SU(2)^2*U(1)_X gauge group with matter in fundamental and antisymmetric tensor representations only. The up, down, charged lepton and neutrino Yukawa matrices are distinguished…
Radiative symmetry breaking is studied in a superstring-inspired supersymmetric model which is extended with a low energy extra $U(1)$ symmetry. In this model the $\mu$-problem is radiatively solved in an automatic way. The right-handed…
In four dimensional superstring models, the gauge group normally contains extra U(1)s that are broken at a high energy scale. We show that the presence of the extra U(1)s is crucial for the phenomenological viability of string scenarios,…
Our contribution sets out to investigate the phenomenology of a gauge model based on an $SU_{L}(2) \times U_{R}(1)_{Q} \times U(1)_{Q'}$-symmetry group. The model can accommodate, through its symmetry-breaking pattern, a candidate to a…
We discuss the phenomenology of a light U(1) gauge boson, $\gamma_B$, that couples only to baryon number. Gauging baryon number at high energies can prevent dangerous baryon-number violating operators that may be generated by Planck scale…
We consider a recent proposal by Dimopoulos and Kaplan to embed the electroweak SU(2)_L X U(1)_Y into a larger group SU(3)_W X SU(2) X U(1) at a scale above a TeV. This idea is motivated by the prediction for the weak mixing angle sin^2…
Contrary to the common lore based on naive dimensional analysis, the seesaw scale for neutrino masses can be naturally in the TeV range, with small parameters coming from radiative corrections. We present one such class of type-I seesaw…
We present a model based on the $SU(3)_C\otimes SU(3)_L\otimes U(1)_X$ gauge symmetry that relates the mass hierarchy of the fermions with the solution to the strong CP problem through the $U(1)_{PQ}$ Peccei-Quinn symmetry. This last…
Many models beyond the Standard Electroweak Theory, top-down or bottom-up, contain extensions of the gauge symmetry group by extra U(1)' factors which can be understood or treated as subgroups of E(6). A brief overview of such models is…
Type II string compactifications to 4d generically contain massless Ramond-Ramond U(1) gauge symmetries. However there is no massless matter charged under these U(1)'s, which makes a priori difficult to measure any physical consequences of…
We use level truncated superstring field theory to obtain the effective potential for the Wilson line marginal deformation parameter which corresponds to the constant vacuum expectation value of the U(1) gauge field on the D-brane in a…
We discuss the phenomenology of a light U(1) gauge boson, $\gamma_B$, that couples only to baryon number. We assume that the new U(1) gauge symmetry is spontaneously broken and that the $\gamma_B$ mass is smaller than $m_Z$. Nevertheless,…
Recently, a number of authors have challenged the conventional assumption that the string scale, Planck mass, and unification scale are roughly comparable. It has been suggested that the string scale could be as low as a TeV. In this note,…
An extension of the Standard Model to the local gauge group $SU(3)_c\otimes SU(3)_L\otimes U(1)_X$ which is a subgroup of the electroweak-strong unification group $E_6$ is analyzed. The mass scales, the gauge boson masses, and the masses…
We investigate a supersymmetric theory with an extra U(1) gauge symmetry surviving down to low energies. The extra U(1) is assumed to originate from an E$_6$ grand unified theory (GUT). We show that if one assumes universal soft…
Numerical evidence for a new dynamical mechanism of elementary particle mass generation has been found by lattice simulation in a simple, yet highly non-trivial SU(3) gauge model where a SU(2) doublet of strongly interacting fermions is…
This paper discusses the minimal quiver gauge theory embedding of the standard model that could arise from brane world type string theory constructions. It is based on the low energy effective field theory of D-branes in the perturbative…
We explore the phenomenology of an extra U(1) gauge boson which primarily couples to standard model gauge bosons. We classify all possible parity-odd couplings up to dimension 6 operators. We then study the prospects for the detection of…
We consider a Standard Model extension by a heavy charged scalar gauged only under the $U_{Y}(1)$ weak hypercharge gauge group. Such an extension, being gauge invariant with respect to the SM gauge group, is a simple special case of the…
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…