相关论文: Stable Superstring Relics

The U$\mu\nu$SSM is a $U(1)'$ extension of the $\mu\nu$SSM supersymmetric model, where baryon-number-violating operators as well as explicit mass terms are forbidden, and the potential domain wall problem is avoided. The gauge…

Four-dimensional string theories predict in general the existence of light exotic particles with fractional electric charges. Such particles could escape present observations if they are confined by a gauge group of the "hidden" sector into…

We find constraints on the highest scale of symmetry breaking of a model with gauge symmetry $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$ with heavy neutral leptons in the fermion triplets, calculating the anomalous magnetic moment of the muon…

Phenomenologically viable string vacua may require incorporating Kac-Moody algebras at level $\geq 2$. We exploit the free fermionic formulation to construct N=(0,2) world-sheet supersymmetric string models with specific phenomenological…

We demonstrate the existence of heterotic-string vacua that are free of massless exotic fields. The need to break the non-Abelian GUT symmetries in k=1 heterotic-string models by Wilson lines, while preserving the GUT embedding of the…

We continue the investigation of the physics implications of a class of flat directions for a prototype quasi-realistic free fermionic string model (CHL5), building upon the results of the previous paper in which the complete mass spectrum…

We study dark matter (DM) which is cosmologically long-lived because of standard model (SM) symmetries. In these models an approximate stabilizing symmetry emerges accidentally, in analogy with baryon and lepton number in the renormalizable…

The H1 and ZEUS collaborations have recently reported a significant excess of events at high $Q^2$ in positron-proton collisions. While there exists insufficient data to conclusively determine the origin of this excess, one possibility is…

Many extensions of the Standard Model have to face the problem of new unsuppressed baryon-number violating interactions. In supersymmetry, the simplest way to solve this problem is to assume R-parity conservation. As a result, the lightest…

We show that there exist massive perturbative states of the ten dimensional Green-Schwarz closed superstring that are stabilized against collapse due to presence of fermionic zero modes on its worldsheet. The excited fermionic degrees of…

Since it has been pointed out that physics beyond the Standard Model may be constrained by gravitational waves from cosmic strings, it has been more important to clarify in what cases cosmic strings are formed. We study the stability of the…

In the context of the minimal supersymmetric standard model (MSSM), we discuss the introduction of exotic matter below the string scale $M_X$ in order to achieve gauge unification at $M_X$ (a constraint of a large class of string models).…

I investigate the phenomenology of supersymmetric models with extra vector-like supermultiplets that couple to the Standard Model gauge fields and transform as the fundamental representation of a new confining non-Abelian gauge interaction.…

Quasi--realistic heterotic-string models in the free fermionic formulation typically contain an anomalous U(1), which gives rise to a Fayet-Iliopolous term that breaks supersymmetry at the one--loop level in string perturbation theory.…

The recent conjecture of possible equivalence between the string scale $M_S$ and the minimal supersymmetric standard model unification scale M_U ~ 2.5 x 10^{16} GeV is considered in the context of string models. This conjecture suggests…

We consider the possibility that dark matter is stabilised by a discrete $Z_2$ symmetry which arises from a subgroup of a $U(1)'$ gauge symmetry, spontaneously broken by integer charged scalars, and under which the chiral quarks and leptons…

We systematically study and classify scotogenic models with a local U(1) gauge symmetry. These models give rise to radiative neutrino masses and a stable dark matter candidate, but avoid the theoretical problems of global and discrete…

We investigate a large class of supersymmetric SO(10) grand unified theories within the framework of gauge-mediated supersymmetry breaking. We start with the most general messenger sector and imbedd the standard model gauge group into…

In the framework of the four dimensional heterotic superstring with free fermions we present a revised version of the rank eight Grand Unified String Theories (GUST) which contain the $SU(3)_H$-gauge family symmetry. We also develop some…

We propose a mechanism that the soft supersymmetry breaking masses can be induced from the dynamical rearrangement of local U(1) symmetry in a five-dimensional model. The U(1) symmetry possesses several extraordinary features. The…