Non-universal soft scalar masses in supersymmetric theories

The existence of non--universal soft masses is the most general situation in supersymmetric theories. We study the consecuences that this situation has for the low--energy sparticle spectrum. In particular, we analize in detail the contribution to the scalar mass renormalization group equations of the $U(1)_Y$ D--term. We obtain analytic expressions for the evolution of masses of the three generations and these allow us to show that such a contribution can produce important modifications on the spectrum. The necessity to avoid flavour changing neutral currents does not constrain this result. Finally, we discuss a realistic example in the context of string theory where the departure from universality is large.Comment: Latex, 13 pages + 3 figs.(avalaible upon request

Applying virtual reality and augmented reality to the tourism experience: a comparative literature review

Purpose The purpose of this paper is to investigate how previous literature has analyzed the role of augmented reality and virtual reality in the field of tourism, distinguishing between studies focused on one technology or the other as both have characteristics that profoundly differentiate them. Design/methodology/approach This study carries out a critical review to assess and synthesize the literature on augmented reality and virtual reality in tourism. Literature searches are conducted using various keywords, resulting in a selection of 84 articles (19 on augmented reality and 65 on virtual reality) from 39 indexed journals. Findings The research findings demonstrate an increasing scholarly focus on exploring the application of virtual reality and augmented reality within the realm of tourism. These results highlight a noticeable progression in recent years with respect to different matters, such as methodologies, used theories or considered variables, among others. Based on these results, it is proposed a future research agenda that seeks to establish a cohesive framework and drive the development of both augmented reality and virtual reality research in tourism. Originality/value By conducting an individual and comparative review of the literature on the application of augmented reality and virtual reality in tourism, this research helps elucidate the specific lines of research for each technology while providing a better understanding of how each technology can be used to generate effective tourist experiences

CP Violation By Soft Supersymmetry Breaking Terms in Orbifold Compactifications

The possibility of spontaneous breaking of CP symmetry by the expectation values of orbifold moduli is investigated with particular reference to $CP$ violating phases in soft supersymmetry breaking terms. The effect of different mechanisms for stabilizing the dilaton and the form of the non-perturbative superpotential on the existence and size of these phases is studied. Non-perturbative superpotentials involving the absolute modular invariant $j(T)$, such as may arise from F-theory compactifications, are considered.Comment: LaTeX file 12 pages, A reference amended and a typo corrected. To appear in Phys.Lett.

Unification of couplings and soft supersymmetry breaking terms in 4D superstring models

We consider the predictions for the hierarchy of mass scales, the fine structure constant, the radii of compactification and the soft SUSY breaking terms which follow if SUSY breaking is triggered by a gaugino condensate.Comment: 16 pages (LaTeX) Oxford preprint OUTP-93-32

Morfología y Productividad Carnicera

Ministerio de Medio Ambiente y Medio Rural y Marin

Problems for Supersymmetry Breaking by the Dilaton in Strings from Charge and Color Breaking

The general constraints on the parameter space of soft-breaking terms, in order to avoid dangerous charge and color breaking minima, are applied to the four-dimensional string scenario where the dilaton is the source of supersymmetry breaking (dilaton-dominated limit). The results indicate that the whole parameter space is excluded on these grounds after imposing the present experimental data on the top mass. The inclusion of a non-vanishing cosmological constant does not improve essentially the prospects. Possible way-outs to this situation are briefly discussed.Comment: 11 pages LaTex + 3 figures including psfig.tex. (No changes to the paper, only some references added

Modular Symmetries of Threshold Corrections for Abelian Orbifolds with Discrete Wilson Lines

The modular symmetries of string loop threshold corrections for gauge coupling constants are studied in the presence of discrete Wilson lines for all examples of abelian orbifolds, where the point group is realised by the action of Coxeter elements or generalised Coxeter elements on the root lattices of the Lie groups.Comment: 36 pages, Late

Unification Scale in String Theory

We study the unification scale and gauge coupling constant in 4D string theory. We show that the fine structure constant is determined by the dimension of the hidden gauge group and only $SU(6)$ and $SO(9)$ are consistent with minimal string unification while the unification scale can be of order of $10^{16}\,GeV$.Comment: 12 pages (LaTeX