scholarly journals A MINI-REVIEW OF CONSTRAINTS ON EXTRA DIMENSIONS

2002 ◽  
Vol 17 (24) ◽  
pp. 1551-1558 ◽  
Author(s):  
YOSUKE UEHARA

We present a mini-review of the present constraints of the large extra dimension scenario. We show many experiments and considerations that can constrain the fundamental scale of the large extra dimension. We observe that constraints come from collider experiments are much weaker than those of astrophysical and cosmological considerations. When the number of extra dimension n is smaller than four, the constraint is so strong that the large extra dimension scenario cannot solve hierarchy problem. But when n ≥ 4 there is still possibility that it can solve the hierarchy problem.

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Thiago R. P. Caramês ◽  
J. M. Hoff da Silva

AbstractWe investigate a braneworld model generated by a global monopole in the context of Brans–Dicke gravity. After solving the dynamical equations we found a model capable to alleviate the so-called hierarchy problem. The obtained framework is described by a hybrid compactification scheme endowed with a seven-dimensional spacetime, in which the brane has four non-compact dimensions and two curled extra dimensions. The relevant aspects of the resulting model are studied and the requirements to avoid the well known seesaw-like behavior are discussed. We show that under certain conditions it is possible to circumvent such a pathological behavior that characterizes most of the models that exhibit hybrid compactification. Lastly, we deepen our analysis by considering possible extensions of this model to a setup with multiple branes and orbifold-like extra dimension. For this, we compute the consistency conditions to be obeyed by this more general configuration as predicted by the braneworld sum rules formalism. This study indicates the possibility of exclusively positive brane tensions in the model.


2020 ◽  
Vol 35 (30) ◽  
pp. 2050182
Author(s):  
Florian Nortier

In this paper, we propose to compactify a single Large Extra Dimension (LED) on a star/rose graph with a large number of identical leaves/petals. The 5D Planck scale can be chosen to be [Formula: see text] TeV which can provide a path to solve the gauge hierarchy problem. The leaf/petal length scale is of [Formula: see text], where [Formula: see text] GeV is the weak scale, without the large geometrical hierarchy of the traditional LED models to stabilize. The 4D fields of the SM are localized on a 3-brane at the central vertex of the star/rose graph. We predict a tower of feebly coupled weak scale Kaluza–Klein (KK) gravitons below a regime of strongly coupled gravitational phenomena above the TeV scale. Moreover, we reformulate in our setup the LED mechanism to generate light Dirac neutrinos, where the right-handed neutrinos are KK-modes of gauge singlet fermions propagating in the bulk. A large number of KK-gravitons and KK-neutrinos interact only gravitationally and thus constitute a hidden sector.


2005 ◽  
Vol 20 (24) ◽  
pp. 1845-1857 ◽  
Author(s):  
E. O. ILTAN

We study [Formula: see text], i = e, μ, τ decays in the two-Higgs doublet model, with the inclusion of one and two spatial non-universal extra dimensions. We observe that the branching ratio is sensitive to two extra dimensions in contrary to a single extra dimension.


Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 831-838
Author(s):  
Massimo Fioranelli ◽  
Alireza Sepehri ◽  
Maria Grazia Roccia ◽  
Mahdieh Ghasemi

Abstract Recently, a method for calculating the quantum spectrum of black holes has been proposed. We show that this method can be applied for radiations of 4 + n - dimensional water around a DNA. In this model, DNA acts like a black hole and produces a curved space-time in a water around it. In these conditions, molecules of water in four dimensional universe are entangled with some DNA-like structures in extra dimension. Consequently, the effects of structures of water in extra dimensions can be observed in four dimensions. The entangled structures emit some quantum spectrum which can be transmitted to pure waters. These waves produce a curved space-time in pure water and make an entanglement between structure of water on four and DNA-like structures in extra dimensions. As a result, some signatures of DNAs can be observed in pure water. This model helps us to understand the reason for the emergence of life on the earth. To explain the model better, we unify Darwin’s theory with string theory in a new Darwinian’s string theory. In this theory, a zero dimensional manifold decays into two types of closed strings. One type decays into open strings and then these strings join to each other and form cosmos. Another type decays into open strings which form biological matters like DNAs and molecules of water in universe and anti-DNAs and anti-water in anti-universe. Thus, DNAs and molecules water are connected to each other and anti-DNAs and molecules of anti-water in anti-universe through some closed strings. These strings helps to molecules of water to store their informations in extra dimension and have long time memory. Because, information that are transformed into extra dimensions through closed strings, could be returned into universe. Also, these closed strings could have the main role in DNA transduction. Because, they connect two tubes one including water and DNA and another pure water in universe to two tubes including anti-DNA and water in anti-universe and transform properties of DNA into pure water. As a result, Darwinian string theory can confirm both water memory and DNA transduction. Finally, this theory response to this question that why memory of water couldnt remain for a long time. In this model, open strings which connects atoms in universe with anti-atoms in anti-universe interact with open strings which connects molecules of water and anti-water and decrease their entanglement. This causes that exchanging information between water and anti-water decreases and memory is dis-appeared.


2013 ◽  
Vol 718 (3) ◽  
pp. 1020-1023 ◽  
Author(s):  
Victor S. Basto-Gonzalez ◽  
Arman Esmaili ◽  
Orlando L.G. Peres

2010 ◽  
Vol 25 (08) ◽  
pp. 1661-1698 ◽  
Author(s):  
ANZHONG WANG ◽  
N. O. SANTOS

In this paper, we present a systematical study of braneworlds of string theory on S1/Z2. In particular, starting with the toroidal compactification of the Neveu–Schwarz/Neveu–Schwarz sector in D + d dimensions, we first obtain an effective D-dimensional action, and then compactify one of the D - 1 spatial dimensions by introducing two orbifold branes as its boundaries. We divide the whole set of the gravitational and matter field equations into two groups, one holds outside the two branes, and the other holds on them. By combining the Gauss–Codacci and Lanczos equations, we write down explicitly the general gravitational field equations on each of the two branes, while using distribution theory we express the matter field equations on the branes in terms of the discontinuities of the first derivatives of the matter fields. Afterwards, we address three important issues: (i) the hierarchy problem; (ii) the radion mass; and (iii) the localization of gravity, the four-dimensional Newtonian effective potential and the Yukawa corrections due to the gravitational high-order Kaluza–Klein (KK) modes. The mechanism of solving the hierarchy problem is essentially the combination of the large extra dimension and warped factor mechanisms together with the tension coupling scenario. With very conservative arguments, we find that the radion mass is of the order of 10-2 GeV. The gravity is localized on the visible brane, and the spectrum of the gravitational KK modes is discrete and can be of the order of TeV. The corrections to the four-dimensional Newtonian potential from the higher order of gravitational KK modes are exponentially suppressed and can be safely neglected in current experiments. In an appendix, we also present a systematical and pedagogical study of the Gauss–Codacci equations and Israel's junction conditions across a (D - 1)-dimensional hypersurface, which can be either spacelike or timelike.


2012 ◽  
Vol 27 (21) ◽  
pp. 1250127 ◽  
Author(s):  
A. NICOLAIDIS

Theories with large extra dimensions may be tested using sterile neutrinos living in the bulk. A bulk neutrino can mix with a flavor neutrino localized in the brane leading to unconventional patterns of neutrino oscillations. A resonance phenomenon, strong mixing between the flavor and the sterile neutrino, allows one to determine the radius of the large extra dimension. If our brane is curved, then the sterile neutrino can take a shortcut through the bulk, leading to an apparent superluminal neutrino speed. The amount of "superluminality" is directly connected to parameters determining the shape of the brane. On the experimental side, we suggest that a long baseline neutrino beam from CERN to NESTOR neutrino telescope will help to clarify these important issues.


2009 ◽  
Vol 60 (1) ◽  
pp. 17-23 ◽  
Author(s):  
J. Abdallah ◽  
◽  
P. Abreu ◽  
W. Adam ◽  
P. Adzic ◽  
...  

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