Meeting on Extra Dimensions

November 20-22, 2013, Tuxtla Gutierrez, Mexico

Venue: Screening Room of the Central Library in Campus I (Sala de Proyección de la Biblioteca Central en el Campus I).
Deadline for the application for financial support November 1, 2013.

Modern theoretical physics is facing a series of challenges to explain several open problems, from the theoretical and experimental/observational viewpoints, in different areas like high energy physics, gravity, astrophysics, cosmology, among others.

From both the theoretical and phenomenological perspectives, some of these open problems can be solved and/or reformulated in a consistent way if one makes use of extra dimensions. Thus, the Meeting on Extra Dimensions will mainly focus on the study and development of higher dimensional approaches towards the solution of the aforementioned open problems. However alternative approaches can also be discussed at the Meeting.


Alfredo Herrera-Aguilar (
Alma D. Rojas (
Elí Santos

Goals and objectives

The aim of the Meeting is to promote the interaction between the participating researchers and professors, most of them active experts on the above mentioned fields. There will be plenary lectures in the morning with plenty of time for questions, technical details and conceptual discussions, as well as tutorial sessions in the afternoon that are aimed to deepen the understanding of the morning presentations. The latter sessions will be particularly useful for students and beginners on a given subject.

It should be stressed that this Meeting is the single event on theoretical physics to be held at the MCTP during 2013. Due to the fact that studies on theoretical physics are rarely offered in Centro American and Caribbean Universities, this Meeting constitutes a good opportunity for regional students to be introduced to actual challenges and relevant open problems of modern physics.


The on-line application form can be accessed here, and please send an updated CV to and


Dr. Rodrigo Alvarado (University of Costa Rica)
Dr. Eloy Ayón-Beato (CINVESTAV, IPN)
Dr. Max Chaves (University of Costa Rica)
Dr. Mariano Chernicoff (FC, UNAM)
Dr. Olindo Corradini (CEFYMAP, UNACH)
Dr. Lorenzo Díaz Cruz (FCFM, BUAP)
Dr. Alfonso Díaz Furlong (UAM-I)
Dr. Alfredo Herrera-Aguilar (IFM, UMSNH & MCTP, UNACH)
Dr. Óscar Loaiza Brito (DCI, UGTO)
Dr. Dagoberto Malagón Morejón (ICF, UNAM)
Dr. Eric Martínez-Pascual (FCFM, BUAP)
Dr. Ulises Nucamendi Gómez (IFM, UMSNH)
Dr. Israel Quiros (CUCEI, UdeG & UCLV, Cuba)
Dr. Saúl Ramos Sánchez (IF, UNAM)
Dr. Alma Rojas (MCTP, UNACH)
Dr. Gianmassimo Tasinato (University of Portsmouth, UK)
Dr. Ivonne Zavala (University of Groningen, The Netherlands)

Topics include

Physics. Physics of extra dimensions applied to gravity, cosmology, astrophysics and high energy physics. Alternative approaches to these fields will also be addressed.


Please click on the talk's title to see the abstract.

Day 1: Wednesday, November 20, 2013.

9:00-10:10 A Z_4 flavor model with radiative neutrino mass generation Dr. Alma D. Rojas (MCTP, UNACH)
10:10-11:20 Z_4 flavor model in Randall Sundrum I: a five-dimensional extension of the Standard Model Dr. Olindo Corradini (CEFYMAP, UNACH)
11:20-11:40 Coffee
11:40-12:50 Flavor and Higgs physics in the Randall-Sundrum geometry Dr. Alfonso Díaz Furlong (UAM-I)
12:50-14:00 The road to Stockholm: From BEH to the Higgs discovery at the LHC Dr. Lorenzo Díaz Cruz (FCFM, BUAP)
14:00-16:00 Lunch
16:00-17:10 About inner and outer relativistic solutions on 5D differentiable manifolds Dr. Rodrigo Alvarado Marín (UCR)
17:10-17:30 Coffee
17:30-18:40 Nonlinearly charged Lifshitz black holes Dr. Eloy Ayón-Beato (CINVESTAV, IPN)
18:40-19:30 Discussion and tutorial session

Day 2: Thursday, November 21, 2013.

09:00-10:10 De Sitter vacua from non-geometric flux compactifications Dr. Óscar Loaiza Brito (DCI, UGTO)
10:10-11:20 Some progress in string phenomenology Dr. Saúl Ramos Sánchez (IF, UNAM)
11:20-11:40 Coffee
11:40-12:50 The Disformal Dark D-brane Sector of the Universe Dr. Ivonne Zavala (University of Groningen)
12:50-14:00 Quarkonium dissociation by anisotropy in a strongly coupled CFT Dr. Mariano Chernicoff (FC, UNAM)
14:00-16:00 Lunch
16:00-17:10 The cosmological constant problem Dr. Ulises Nucamendi Gómez (IFM, UMSNH)
17:10-17:30 Coffee
17:30-18:40 New perspectives for dark energy model building Dr. Gianmassimo Tasinato (University of Portsmouth)
18:40-19:30 Discussion and tutorial session

Day 3: Friday, November 22, 2013.

09:00-10:10 Aspects of braneworld models: localization properties Dr. Dagoberto Malagón Morejón (ICF, UNAM)
10:10-11:20 Cosmology on the brane Dr. Israel Quiros (CUCEI, UdeG & UCLV, Cuba)
11:20-11:40 Coffee
11:40-12:50 Cosmological effects in expanding braneworlds Dr. Alfredo Herrera-Aguilar (IFM, UMSNH & MCTP, UNACH)
12:50-14:00 The reheating period and gravity: a possible new component for dark matter and dark energy Dr. Max Chaves (UCR)
14:00-15:30 Lunch
15:30-17:00 Visit to MCTP premises
17:00-17:20 Coffee
17:20-18:30 Hidden Symmetries and Gauge Structure of Compactified Yang-Mills Theories with an arbitrary number of universal extra dimensions Dr. Eric Martínez-Pascual (FCFM, BUAP)
18:30-19:00 General Discussion

Title: Z_4 flavor model with radiative neutrino mass generation

Abstract: Following a minimal approach, we construct a renormalizable flavor model with Z_4 as flavor symmetry in both the quark and lepton sector. In this approach we do not z introduce right handed neutrinos, and a minimum of two Higgs SU(2) doublets and a scalar singlets are required to obtain de Nearest Neighbor Interaction form for charged fermions and to generate neutrino masses radiatively. We verified that all fermion masses and mixing angles in the model are in agreement with experimental data. Since in our model neutrinos are Majorana we analysed also the contribution to neutrinoless double beta decay. We also implemented this flavor symmetry in the context of extra dimensions proposing a five-dimensional extension of the Standard Model (see Olindo's talk).

Title: Z_4 flavor model in Randall Sundrum I: a five-dimensional extension of the Standard Model

Abstract: Randall Sundrum models provide a possible explanation of (gauge-gravity) hierarchy, whereas discrete symmetry flavor groups yield a possible description of the texture of Standard Model fermion masses. We use both these ingredients to propose a five-dimensional extension of the Standard Model where the mass hierarchy of the four-dimensional effective field theory is obtained only using localizations parameters of order one.

Title: Flavor and Higgs physics in the Randall-Sundrum geometry

Abstract: Today, with the LHC running, we are living in a very exciting moment for the particle physics community. The recent results of the CMS and ATLAS collaboration on July 4th, 2012, start to show us the path to the future research in the field of particle physics. If this new particle detected at CERN, turns to be the Higgs particle predicted by the Standard Model,it will be the closure of this excellent odel.However, the possibility of having a different Higgs sector, remains open, as we will discuss. With all this excitement,it is the perfect time to study new alternatives beyond the SM. Here we study the Randall-Sundrum Model I.This model was originally proposed to give a solution to the hierarchy problem. But, this model provides another interesting features, for instance, if one promotes all the fields (except the Higgs) to the bulk, it provides an excellent model to explain the so called flavor puzzle, as we will mention. Within the context of the RS model, both in its minimal and custodial versions,we study different aspects of flavor and Higgs physics. Finally, we give a brief comment on Composite Higgs Models (CHMs) within the RS Model.

Title: The road to Stockholm : From BEH to the Higgs discovery at the LHC

Abstract: In this talk we review the early work on the Brout-Englert-Higgs mechanism, and its implementation within the Glashow-Weinberg-Salam model for the partial unification of the eleactroweak interactions. Then, we discuss the work on the Higgs boson phenomenology that allowed to corner its properties and signals, which eventually lead to its discovery at the LHC. With this important piece fitting in the right place, the SM seems complete. What then would be the future of particle physics? Could the LHC find evidence of Susy, composite Higgs or should we give up?

Title: Nonlinearly charged Lifshitz black holes

Abstract: Charged Lifshitz black holes at any dimension D are known only if the dynamical critical exponent is fixed to z=2 (D-2). These configurations are solutions of the Einstein-Proca-Maxwell system with a negative cosmological constant. In this talk we show that it is possible to generalize this charged configurations to any dynamical exponent z>1 by allowing that the electrodynamics behaves nonlinearly. The new black holes belong to a two-parametric family and a new two-parametric nonlinear electrodynamics is introduced in order to support them in companion with the Proca field. This electrodynamics is of the kind necessarily defined in the more general, but less known, so-called (H,P)-formalism since the corresponding constitutive relations are not invertible and their Lagrangian cannot be written as a single function of the invariant of the electromagnetic field strength. The case z=D-2 turns to be critical, giving rise to asymptotically Lifshitz black holes with logarithmic decay supported by a sort of logarithmic electrodynamics. We also show how to extend all these black holes solutions to include nontrivial horizon topologies only by generalizing the proposed electrodynamics.

Title: About inner and outer relativistic solutions on 5D differentiable manifolds

Abstract: In this lecture we discuss a set of 5D vacuum solutions with planar symmetry of Einstein's field equations. These solutions are asymptotically flat and tend to be 4D Minkwoskian when parameters meet certain conditions. General invariance ensures a degree of freedom the form of the solutions and some interesting examples are analyzed. As a typical completely symmetric space, geodesic lines solutions are also exact. Our future research aims to find self-consistent interior solitonic solutions coupled with the exterior one mentioned above, a topic briefly commented at the end of the talk.

Title: De Sitter vacua from non-geometric flux compactifications

Abstract: Type IIB non-geometric flux tori compactifications with orientifold 3-planes is a natural candidate to search for classical stable dS and AdS vacua. In this talk I will report some concrete examples we find by implementing a genetic algorithm on isotropic, semi-isotropic and anisotropic tori compactifications. I will also comment on the existence of suitable conditions for slow-roll inflation within these models.

Title: Some progress in string phenomenology

Abstract: We shall discuss some phenomenologically appealing features and challenges of heterotic orbifold compactifications, aiming at a theory of particles and cosmology. Obtaining globally consistent string constructions with properties akin to those of the (N)MSSM is made now trivial by using "The Orbifolder", an open-source computer code. The models constructed this way offer plenty of resources to possibly arrive at observable physics.

Title: The Disformal Dark D-brane Sector of the Universe

Abstract: Disformally coupled cosmologies are shown to emerge in the Dirac-Born-Infeld scenarios of Type II string theory compactifications, when matter resides on a moving D-brane. When such matter interacts only very weakly with the standard model particles, it can provide a natural candidate for the dark sector in the universe with a clear geometrical interpretation. The forms of the coupling functions among the dark sectors are given in terms of the (warped) extra-dimensional geometry, and are thus constrained by the theory. The resulting cosmologies are studied using both dynamical system analysis and numerics. In particular, a disformal scaling solution is discovered and applied to construct realistic cosmologies compatible with the parameters arising from the string theory set up.

Title: Quarkonium dissociation by anisotropy in a strongly coupled CFT

Abstract: We compute the screening length for heavy mesons moving through an anisotropic, strongly coupled N=4 super Yang-Mills plasma by means of its gravity dual. We present the results for arbitrary velocities and orientations of the mesons, as well as for arbitrary values of the anisotropy. For generic motion we find that: (i) mesons dissociate above a certain critical value of the anisotropy, even at zero temperature; (ii) there is a limiting velocity for mesons in the plasma, even at zero temperature; (iii) in the ultra-relativistic limit the screening length scales as (1-v2)^{1/2}, in contrast with the isotropic result (1-v2)^{1/4}.

Title: The cosmological constant problem

Abstract: Since Albert Einstein introduced the energy density of the cosmological constant in the General Theory of Relativity, a deep discussion has been emerged about its value in the Universe we live. Nowadays, the predicted theoretical value is approximately 2 x 10^{110} erg/cm^{3}. In this talk we shall show that, based on recent cosmological observations and Bayesian statistics, the inferred value of the cosmological constant density in our Universe is approximately 2 x 10^{-10} erg/cm^{3}. This fact gives rise to the so-called “cosmological constant problem” which amounts to having a ratio between the value inferred from cosmological observations and the theoretically predicted value of order 10^{120}. This discrepancy has been called the “the worse historical prediction in Physics” and is a currently open problem.

Title: New perspectives for dark energy model building

Abstract: I will talk on new promising approaches to build models of dark energy, based on massive gravity and on Galileons. I will emphasize the crucial role of symmetry principles for constructing new scenarios that explain the current acceleration of our universe, and I will discuss intriguing phenomenological aspects of the resulting models. Moreover, I will also critically examine the theoretical challenges that are left for the future.

Title: Aspects of braneworld models: localization properties.

Abstract: One of the main features of the Randall—Sundrum model (RS) is to address the hierarchy problem without contradictions with the low energy physics. In particular, the 4D General Relativity is recovered on the brane. An interesting aspect is if this last property is robust under a generalization of the RS scenario to 5D thick braneworld models. In this work we study the localization properties of gravity and bulk matter fields in a thick braneworld model. Our scenario is a warped 5D smooth braneworld with 4D Minkowski geometry generated by a bulk scalar field non–minimally coupled to gravity and the Gauss–Bonnet term. We switch on/off the parameters associated to the non–minimal coupling and the higher order curvature terms and analyze the behaviour of the localization properties of the gravity in each case. It is shown that at first order of the fluctuations and in all the cases, the massless tensor mode (the 4D graviton) is localized on the brane, while the vector and scalar modes are not confined to the brane. Additionally we show some partial results related with the effects of the second order fluctuations on gravity localization.

Title: Cosmology on the brane

Abstract: A brief review about the way braneworld models of the universe modify the cosmological dynamics is given. Randall-Sundrum, Dvali-Gabadadze-Porrati, as well as -- briefly -- thick brane models will be reviewed.

Title: Cosmological effects in expanding braneworlds

Abstract: We present some inflating braneworld scenarios generated by pure gravity and cosmological constants in 4D and 5D. In this scenario localization of gravity takes place without the aid of either Dirac distribution functions or scalar fields. By introducing a spatially anisotropic ansatz for the metric and a scalar field of phantom type, we find a mechanism that exponentially isotropizes the braneworld for a wide class of initial conditions: under the action of the 4D cosmological constant, the anisotropic braneworld super-exponentially isotropizes by itself, rendering a 3-brane with de Sitter symmetry embedded in a 5D de Sitter space-time, while the phantom scalar field exponentially vanishes. By adding delta distribution functions to the system, we also find a novel dynamical mechanism in which the anisotropic nature of the primordial metric gives rise to i) inflation along certain spatial dimensions, and ii) deflation and a shrinking reduction of the number of spatial dimensions along other directions. This dynamical mechanism can be relevant for dimensional reduction in string and other higher dimensional theories in the attempt of getting a 4D isotropic expanding space-time.

Title: The reheating period and gravity: a possible new component for dark matter and dark energy

Abstract: The reheating period of inflation is discussed. It is pointed out that that a background inflaton field falling down a potential can and should undergo small local quantum tunneling. It is shown how these effects produce small pockets of gravity with sizable energy. These pockets can gravitate either positively or negatively (terms with either sign occur in the Ricci tensor), so they can be components of dark matter or dark energy. We comment on the possible weakening of these pockets as the Universe expands, the point being that they do get flatter, but also they get bigger. Their gravitational field has to be calculated from an integral over the field density, so, as long as the integral is over all the growing pocket, its value is unchanging. A common cause for both dark matter and dark energy would explain why their quantities are of the same order of magnitude.

Title: Hidden Symmetries and Gauge Structure of Compactified Yang-Mills Theories with an arbitrary number of universal extra dimensions

Abstract: A comprehensive study of the gauge structure of Yang-Mills theories with an arbitrary number of universal extra dimensions (UEDs) is presented. The analysis is exemplified using the case of two UEDs. At the Lagrangian level, the novel ingredient, with respect to the case of only one UED, is the way in which some sort of Higgs mechanism operates in order to intricately produce KK modes in the extra dimensions that resemble pseudo Goldstone bosons; these in turn can be eliminated via a particular non-standard gauge transformation. At the Hamiltonian level, the gauge generator of the so-called standard and non-standard gauge transformations is obtained via the Dirac formalism for constrained systems and a suitable canonical transformation. This material paves the way for subsequent discussions concerning the quantization, using for example field/anti-field formalism, of these theories

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