More about neutron Majorana mass from exotic instantons: An alternative mechanism in low-scale string theory

Abstract

We discuss an alternative for baryon-violating six quarks transition in the context of low scale string theory. In particular, with M[Formula: see text] = 10–103 TeV, such a transition can be mediated by two color-triplets through a quartic coupling with down-quarks, generated by exotic instantons, in a calculable and controllable way. We show how flavor-changing neutral currents (FCNCs) limits on color-triplet mass are well compatible with [Formula: see text] oscillation ones. If an [Formula: see text] transition was found, this would be an indirect hint for our model. This would strongly motivate searches for direct channels in proton–proton colliders. In fact, our model can be directly tested in an experimentally challenging 100–1000 TeV proton–proton collider, searching for our desired color-triplet states and an evidence for exotic instantons resonances, in addition to stringy Regge resonances, anomalous Z[Formula: see text]-bosons and gauged megaxion. In particular, our scenario can be related to the 750 GeV diphoton hint identifying it with the gauged megaxion dual to the B-field. On the other hand, this scenario is compatible with TeV-ish color triplets visible at large hadron collider (LHC) and with 1–10 TeV string scale, i.e. stringy resonances at LHC.