相关论文: Stabilization of the Electroweak String by the Bos…
Using a physical renormalisation scheme we derive mass-dependent renormalisation group equations for the running of the Higgs quartic coupling within the Standard Model. Subsequently, we accurately take into account weak scale thresholds,…
It has been shown that the Dimopoulos-Wilczek (or missing-VEV) mechanism for doublet-triplet splitting can be implemented in $SU(5) \times SU(5)$ models, which requires no adjoint Higgs fields. This is an advantage from the point of view of…
We consider the minimal U(1)$_{B-L}$ extension of the Standard Model (SM) with the classically conformal invariance, where an anomaly free U(1)$_{B-L}$ gauge symmetry is introduced along with three generations of right-handed neutrinos and…
The zero-width approximation (ZWA) restricts the intermediate unstable particle state to the mass shell and, when combined with the decorrelation approximation, fully factorizes the production and decay of unstable particles. The ZWA…
We construct type I string models with supersymmetry broken by compactification that are non-tachyonic and have exponentially small effective potential at one-loop. All open string moduli can be stabilized, while the closed string moduli…
We carry out lattice simulations of a cosmological electroweak phase transition for a Higgs mass m_h ~ 126 GeV. The analysis is based on a dimensionally reduced effective theory for an MSSM-like scenario including a relatively light…
Motivated by the neutrino data, an extension of the Standard Model with three Higgs-boson doublets has been proposed. Imposing an O(2) x Z2 family symmetry, a neutrino mixing matrix with theta23 = pi/4 and theta13 = 0 appears in a natural…
The $Z_2\times Z_2$ heterotic string orbifold gives rise to a large space of phenomenological three generation models that serves as a testing ground to explore how the Standard Model of particle physics may be incorporated in a theory of…
We present a new global fit to precision electroweak data, including new low- and high-energy data and analyzing the radiative corrections arising from the minimal symmetry breaking sectors of the Standard Model (SM) and its supersymmetric…
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…
Considering SO(32) heterotic string theory compactified on a torus of dimension 4 and less, stability of non-supersymmetric states is studied. A non-supersymmetric state with robust stability is constructed, and its exact stability is…
In a recent paper, we introduced a new Little Higgs model, which contains the gauge structure $SU(2)^3\times U(1)$, embedded in an approximate global $SO(5)\times SO(5)$ symmetry. After breaking to the standard model, $SU(2)_L \times…
In this paper, we establish a fully string-theoretic framework for calculating one-loop Higgs masses directly from first principles in perturbative closed string theories. Our framework makes no assumptions other than worldsheet modular…
In this paper, we try to construct an electroweak model which avoids using Higgs mechanism. We simultaneously introduce two sets of gauge bosons so as to keep the masses of gauge bosons $W^{\pm}$ and $Z$ non-zero without using Higgs…
We show that stable local cosmic strings are a generic prediction of supersymmetric models where supersymmetry is broken at scales within a few orders of magnitude of the weak scale and is fed down to the observable sector by gauge…
It is widely believed that the top loop corrections to the Higgs effective potential destabilise the electroweak (EW) vacuum and that, imposing stability, lower bounds on the Higgs mass can be derived. With the help of a scalar-Yukawa…
We consider a class of heterotic N=2 -> 0 super no-scale Z_2-orbifold models. An appropriate stringy Scherk-Schwarz supersymmetry breaking induces tree level masses to all massless bosons of the twisted hypermultiplets and therefore…
It is shown that the heterotic string emerges as a soliton in the type I superstring theory in ten dimensions. The collective coordinates of the soliton are described by a smooth, chiral worldsheet theory. There are eight bosonic and eight…
In this paper we extend the analysis of the stability of an homogeneous black string in the presence of a negative cosmological constant with minimally coupled scalar fields. We recall the linear stability of this solutions under generic…
String theory has no parameter except the string scale $M_S$, so the Planck scale $M_\text{Pl}$, the supersymmetry-breaking scale, the EW scale $m_\text{EW}$ as well as the vacuum energy density (cosmological constant) $\Lambda$ are to be…