Supersymmetric standard model spectra from RCFT orientifolds

Abstract

We present supersymmetric, tadpole-free d = 4, N = 1 orientifold vacua with a three family chiral fermion spectrum that is identical to that of the Standard Model. Starting with all simple current orientifolds of all Gepner models we perform a systematic search for such spectra. We consider several variations of the standard four-stack intersecting brane realization of the standard model, with all quarks and leptons realized as bifundamentals and perturbatively exact baryon and lepton number symmetries, and with a U (1) Y vector boson that does not acquire a mass from Green-Schwarz terms. The number of supersymmetric Higgs pairs H 1 + H 2 is left free. In order to cancel all tadpoles, we allow a "hidden" gauge group, which must be chirally decoupled from the standard model. We also allow for non-chiral mirror-pairs of quarks and leptons, non-chiral exotics and (possibly chiral) hidden, standard model singlet matter, as well as a massless B-L vector boson. All of these less desirable features are absent in some cases, although not simultaneously. In particular, we found cases with massless Chan-Paton gauge bosons generating nothing more than SU (3) × SU (2) × U (1). We obtain almost 180000 rationally distinct solutions (not counting hidden sector degrees of freedom), and present distributions of various quantities. We analyse the tree level gauge couplings, and find a large range of values, remarkably centered around the unification point.

AdS-phobia, the WGC, the Standard Model and Supersymmetry

“…This symmetry is automatically present as a global symmetry in the R-parity conserving MSSM, and indeed the B − L symmetry is gauged in a multitude of string semi-realistic models (see e.g. [71][72][73][74]). A discrete subgroup of U(1) B−L may also be gauged without the full U(1) B−L gauge symmetry surviving at low energies.…”

One in a billion: MSSM-like D-brane statistics

“…In figure 8(a) we give the complete distribution, in 8(b) we allow for maximally three branes in the hidden sector in order to make the result better comparable to [8], where a similar cutoff was imposed for computational reasons. The main difference comes from the fact that we have much fewer models in our ensemble and, more importantly, our models are not constrained to three generations.…”

“…In fact there exist many more models with low values for α s /α w and sin 2 θ, which happen to be the ones fulfilling the relation. These results can also be compared with the analysis of [8], where as in the case of the hidden gauge group one has to take into account that we are dealing with a smaller ensemble and with models that are not constrained to exactly three generations of fermions. The fraction of MSSM-like Gepner models satisfying (28) is found there to be only ca.…”

Chiral D-brane Models with Frozen Open String Moduli

“…Since the scalar components of such chiral multiplets acquire a mass by effect of the N = 0 flux, then the degeneracy of the D-term potential gets lifted, and the FI-terms of the theory are dynamically fixed to vanish. Now, since the FI-terms depend on the Kähler moduli of the compactification, and in particular on the deviation of conditions such as (54), the absence of FI-terms would translate into new constraints for the Kähler moduli, which are hence also lifted. One must bear in mind, however, that this kind of reasoning relies on partial effective field theory results, in which F and D-term potentials arise from apparent different sources.…”