scholarly journals Physics of warped dimensions and continuous spectra

2022 ◽  
Vol 258 ◽  
pp. 06008
Author(s):  
Eugenio Megías ◽  
Manuel Pérez-Victoria ◽  
Mariano Quirós

We study some features of a warped five-dimensional model that solves the hierarchy problem and exhibits a continuum of Kaluza-Klein (KK) modes with a mass gap at the TeV scale. We compute the propagators and spectral functions for massless bulk gauge bosons, and study how the continuum can be reached as the limit of a set of models with discrete spectrum. Finally, we study the low energy effective theory and provide explicit results for the Wilson coefficients.

2009 ◽  
Vol 24 (18) ◽  
pp. 1425-1435 ◽  
Author(s):  
VLADIMIR SHEVCHENKO

The physics of symmetry breaking in theories with strongly interacting quanta obeying infinite (quantum Boltzmann) statistics known as quons is discussed. The picture of Bose/Fermi particles as low energy excitations over nontrivial quon condensate is advocated. Using induced gravity arguments, it is demonstrated that the Planck mass in such low energy effective theory can be factorially (in number of degrees of freedom) larger than its true ultraviolet cutoff. Thus, the assumption that statistics of relevant high energy excitations is neither Bose nor Fermi but infinite can remove the hierarchy problem without necessity to introduce any artificially large numbers. Quantum mechanical model illustrating this scenario is presented.


1999 ◽  
Vol 14 (29) ◽  
pp. 2025-2031 ◽  
Author(s):  
MERAB GOGBERASHVILI

Five-dimensional model with extended dimensions investigated. It is shown that four dimensionality of our world is the result of the stability requirement. Extra component of five-dimensional Einstein's equations that is responsible for trapping of matter fields coincides with the condition of stability.


2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Avirup Shaw

AbstractWe measure the impact of nonvanishing boundary localised terms on $$\Delta B=2$$ Δ B = 2 transitions in five-dimensional Universal Extra Dimensional scenario where masses and coupling strengths of several interactions of Kaluza–Klein modes are significantly modified with respect to the minimal counterpart. In such scenario we estimate the Kaluza–Klein contributions of quarks, gauge bosons and charged Higgs by evaluating the one-loop box diagrams that are responsible for the $$\Delta B=2$$ Δ B = 2 transitions. Using the loop function (obtained from one-loop box diagrams) we determine several important elements that are involved in Wolfenstein parametrisation. Moreover, with these elements we also study the geometrical shape of unitarity triangle. Besides, we compute the quantity $$\Delta M_s$$ Δ M s scaled by the corresponding Standard Model value. Outcomes of our theoretical predictions have been compared to the allowed ranges of the corresponding observables simultaneously. Our current analysis shows that, depending on the parameters in this scenario the lower limit on the inverse of the radius of compactification can reach to an appreciable large value ($$\approx 1.48$$ ≈ 1.48 TeV or even higher).


2013 ◽  
Vol 87 (4) ◽  
Author(s):  
Evelyn Tang ◽  
Matthew P. A. Fisher ◽  
Patrick A. Lee

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
A. de Giorgi ◽  
S. Vogl

Abstract The Kaluza-Klein (KK) decomposition of higher-dimensional gravity gives rise to a tower of KK-gravitons in the effective four-dimensional (4D) theory. Such massive spin-2 fields are known to be connected with unitarity issues and easily lead to a breakdown of the effective theory well below the naive scale of the interaction. However, the breakdown of the effective 4D theory is expected to be controlled by the parameters of the 5D theory. Working in a simplified Randall-Sundrum model we study the matrix elements for matter annihilations into massive gravitons. We find that truncating the KK-tower leads to an early breakdown of perturbative unitarity. However, by considering the full tower we obtain a set of sum rules for the couplings between the different KK-fields that restore unitarity up to the scale of the 5D theory. We prove analytically that these are fulfilled in the model under consideration and present numerical tests of their convergence. This work complements earlier studies that focused on graviton self-interactions and yields additional sum rules that are required if matter fields are incorporated into warped extra-dimensions.


2021 ◽  
Vol 13 (10) ◽  
pp. 5598
Author(s):  
Stasys Mizaras ◽  
Diana Lukmine

Effective formation and implementation of forest policy can only be achieved with orientation to the most important goal—increasing society’s welfare. The global problem is, at present, that the impact of forests on society welfare indexes have not been identified. The aim of the study is to design an assessment model and assess the impact of Lithuanian forests on the society welfare index. The impact of forests was determined by multiplying the country’s welfare of society index by the forest contribution coefficient. In this study, to assess the index of the welfare of Lithuanian society, a five-dimensional model with 16 indicators was applied. The study is based on the Eurostat database and on Lithuanian forestry statistics. The Lithuanian welfare of society index calculated according to the model was 51.4% and the contribution of forests in this index was 3.9%. It represented 7.6% of the index of the welfare of society. Forests have the greatest impact in the environmental dimension, according to the assessment results.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Martin Bauer ◽  
Matthias Neubert ◽  
Sophie Renner ◽  
Marvin Schnubel ◽  
Andrea Thamm

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.


Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.


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