A Note on Modulus-dominated SUSY-breaking (2009)
Maxin, James A., Mayes, Van E., Nanopoulos, D. V.
In models where supersymmetry-breaking is dominated by the Kahler moduli and/or the universal dilaton, the B-parameter at the unification scale should be consistent with the value of tan(beta) at the...
The Search for a Realistic String Model at LHC (2009)
Maxin, James A., Mayes, Van E., Nanopoulos, D. V.
We survey the low-energy supersymmetry phenomenology of a three-family Pati-Salam model constructed from intersecting D6-branes in Type IIA string theory on the T^6/(Z_2 x Z_2) orientifold which...
The MAGIC of SSC and how it affects LHC (2009)
Mavromatos, Nick E., Nanopoulos, D. V.
We discuss the phenomenology of Supercritical String Cosmology (SSC) in the context of Dark Matter constraints on supersymmetric particle physics models at LHC. We also link our results with recent...
Probing a Possible Vacuum Refractive Index with Gamma-Ray Telescopes (2009)
Ellis, John, Mavromatos, N E, Nanopoulos, D V
We have used a stringy model of quantum space-time foam to suggest that the vacuum may exhibit a non-trivial refractive index depending linearly on gamma-ray energy: eta -1 ~ E_gamma/M_QG1, where...
Probing a Possible Vacuum Refractive Index with Gamma-Ray Telescopes (2009)
Ellis, John, Mavromatos, N. E., Nanopoulos, D. V.
We have used a stringy model of quantum space-time foam to suggest that the vacuum may exhibit a non-trivial refractive index depending linearly on gamma-ray energy: eta -1 ~ E_gamma/M_QG1, where...
Supersymmetry Signals of Supercritical String Cosmology at the Large Hadron Collider (2008)
Dutta, Bhaskar, Gurrola, Alfredo, Kamon, Teruki, Krislock, Abram, Lahanas, A. B., Mavromatos, N. E., ...
We investigate the minimal supergravity (mSUGRA) signals at the LHC in the context of supercritical string cosmology (SSC). In this theory, the presence of a time dependent dilaton provides us with a...
Yukawa Corrections from Four-Point Functions in Intersecting D6-Brane Models (2008)
Chen, Ching-Ming, Li, Tianjun, Mayes, V. E., Nanopoulos, D. V.
We discuss corrections to the Yukawa matrices of the Standard Model (SM) fermions in intersecting D-brane models due to four-point interactions. Recently, an intersecting D-brane model has been found...
Derivation of a Vacuum Refractive Index in a Stringy Space-Time Foam Model (2008)
Ellis, Jonathan Richard, Mavromatos, N E, Nanopoulos, D V
It has been suggested that energetic photons propagating in vacuo should experience a non-trivial refractive index due to the foamy structure of space-time induced by quantum-gravitational...
Derivation of a Vacuum Refractive Index in a Stringy Space-Time Foam Model (2008)
Ellis, John, Mavromatos, N. E., Nanopoulos, D. V.
It has been suggested that energetic photons propagating in vacuo should experience a non-trivial refractive index due to the foamy structure of space-time induced by quantum-gravitational...
Erratum (astro-ph/0510172): Robust Limits on Lorentz Violation from Gamma-Ray Bursts (2007)
Ellis, Jonathan Richard, Mavromatos, N E, Nanopoulos, D V, Sakharov, Alexander S, Sarkisyan-Grinbaum, E
We correct the fitting formula used in refs. [1,2] to obtain a robust limit on a violation of Lorentz invariance that depends linearly on the photon energy. The correction leads to a slight increase...
Theory from World-Sheet Defects in Liouville String (2007)
John Ellis, N.E. Mavromatos, D.V. Nanopoulos
We have argued previously that black holes may be represented in a D-brane approach by monopole and vortex defects in a sine-Gordon field theory model of Liouville dynamics on the world sheet....
Realistic Yukawa Textures and SUSY Spectra from Intersecting Branes (2007)
Chen, Ching-Ming, Li, Tianjun, Mayes, V. E., Nanopoulos, D. V.
We study the possible phenomenology of a three-family Pati-Salam model constructed from intersecting D6-branes in Type IIA string theory on the T^6/(Z2 x Z2) orientifold with some desirable...
Albert, J, Aliu, E, Anderhub, H, Antonelli, L A, Antoranz, P, Backes, M, ...
We use the timing of photons observed by the MAGIC gamma-ray telescope during a flare of the active galaxy Markarian 501 to probe a vacuum refractive index ~ 1-(E/M_QGn)^n, n = 1,2, that might be...
Al., J. Albert Et, Ellis, John, Mavromatos, N. E., Nanopoulos, D. V., Sakharov, A. S., Sarkisyan, E. K. G.
We analyze the timing of photons observed by the MAGIC telescope during a flare of the active galactic nucleus Mkn 501 for a possible correlation with energy, as suggested by some models of quantum...
Lahanas, A. B., Mavromatos, N. E., Nanopoulos, D. V.
We show that Supercritical-String-Cosmology (SSC) off-equilibrium and time-dependent-dilaton effects lead to a smoothly evolving dark energy for the last 10 billion years in concordance with all...
MSSM via Pati-Salam from Intersecting Branes on $T^6/(\mathbf{\Z_2} \times \mathbf{\Z_2'})$ (2006)
Chen, Ching-Ming, Mayes, V. E., Nanopoulos, D. V.
We construct an MSSM-like model via Pati-Salam from intersecting D-branes in Type IIA theory on the $\Z_2 \times \Z_2'$ orientifold where the D-branes wrap rigid 3-cycles. Because the 3-cycles are...
Lahanas, A. B., Mavromatos, N. E., Nanopoulos, D. V.
In this work we derive the modifications to the Boltzmann equation governing the cosmic evolution of relic abundances induced by dilaton dissipative-source and non-critical-string terms in...
Ellis, J. R., Mavromatos, N. E., Mitsou, V. A., Nanopoulos, D. V.
We discuss fits of cosmological dark energy models to the available data on high-redshift supernovae. We consider a conventional model with Cold Dark Matter and a cosmological constant (LambdaCDM), a...
UHECR Particle Spectra from Crypton Decays (2005)
Ellis, John, Mayes, V. E., Nanopoulos, D. V.
We calculate the spectra of ultra-high-energy cosmic rays (UHECRs) in an explicit top-down model based on the decays of metastable neutral `crypton' states in a flipped SU(5) string model. For each...
On Geometrical Interpretation of Non-Abelian Flat Direction Constraints (2005)
Cleaver, G. B., Nanopoulos, D. V., Perkins, J. T., Walker, J. W.
In order to produce a low energy effective field theory from a string model, it is necessary to specify a vacuum state. In order that this vacuum be supersymmetric, it is well known that all field...
A. Mershin, A. A. Kolomenski, H. A. Schuessler, D. V. Nanopoulos
We used computer simulation to calculate the electric dipole moments of the α and β tubulin monomers and dimer and found those to be |pα|=552D, |pβ|=1193D and |pαβ|=1740D respectively....
WMAPing out Supersymmetric Dark Matter and Phenomenology (2003)
Lahanas, A. B., Nanopoulos, D. V.
The recent WMAP data provide a rather restricted range of the Cold Dark Matter (CDM) density $ \Omega_{CDM} h^2 $ of unprecedented accuracy. We combine these new data along with data from BNL E821...
Quantum-Gravity Analysis of Gamma-Ray Bursts using Wavelets (2002)
Ellis, J., Mavromatos, N. E., Nanopoulos, D. V., Sakharov, A. S.
In some models of quantum gravity, space-time is thought to have a foamy structure with non-trivial optical properties. We probe the possibility that photons propagating in vacuum may exhibit a...
Lower Limits on Soft Supersymmetry-Breaking Scalar Masses (2001)
Ellis, John, Nanopoulos, D. V., Olive, Keith A.
Working in the context of the CMSSM, we argue that phenomenological constraints now require the universal soft supersymmetry-breaking scalar mass m_0 be non-zero at the input GUT scale. This...
Dark Matter Direct Searches and the Anomalous Magnetic Moment of Muon (2001)
Lahanas, A. B., Nanopoulos, D. V., Spanos, V. C.
In the framework of the Constrained Minimal Supersymmetric Standard Model (CMSSM) we discuss the impact of the recent experimental information, especially from E821 Brookhaven experiment on...
Neutralino Dark Matter Elastic Scattering in a Flat and Accelerating Universe (2000)
Lahanas, A. B., Nanopoulos, D. V., Spanos, V. C.
In SUGRA inspired supersymmetric models with universal boundary conditions for the soft masses, the scalar cross section $\sigma_{scalar}$ for the elastic neutralino--nucleon scattering is in general...
Neutralino relic density in a Universe with a non-vanishing cosmological constant (1999)
Lahanas, A. B., Nanopoulos, D. V., Spanos, V. C.
We discuss the relic density of the lightest of the supersymmetric particles in view of new cosmological data, which favour the concept of an accelerating Universe with a non-vanishing cosmological...
Astrophysical Probes of the Constancy of the Velocity of Light (1999)
Ellis, J., Farakos, K., Mavromatos, N. E., Mitsou, V., Nanopoulos, D. V.
We discuss possible tests of the constancy of the velocity of light using distant astrophysical sources such as gamma-ray bursters (GRBs), Active Galactic Nuclei (AGNs) and pulsars. This speculative...
Elevating the Free-Fermion $Z_2\times Z_2$ Orbifold Model to a Compactification of F-Theory (1998)
Berglund, Per, Ellis, John, Faraggi, Alon E., Nanopoulos, D. V., Qiu, Zongan
We study the elliptic fibrations of some Calabi-Yau three-folds, including the $Z_2\times Z_2$ orbifold with $(h_{1,1},h_{2,1})=(27,3)$, which is equivalent to the common framework of realistic...
String derived MSSM and M-theory Unification (1998)
Cleaver, G. B., Faraggi, A. E., Nanopoulos, D. V.
The recent conjecture of possible equivalence between the string scale $M_S$ and the minimal supersymmetric standard model unification scale M_U ~ 2.5 x 10^{16} GeV is considered in the context of...
A Microscopic Liouville Arrow of Time (1998)
Ellis, John, Mavromatos, N. E., Nanopoulos, D. V.
We discuss the treatment of quantum-gravitational fluctuations in the space-time background as an `environment', using the formalism for open quantum-mechanical systems, which leads to a microscopic...
Toward the M(F)--Theory Embedding of Realistic Free-Fermion Models (1998)
Berglund, Per, Ellis, John, Faraggi, Alon E., Nanopoulos, D. V., Qiu, Zongan
We construct a Landau-Ginzburg model with the same data and symmetries as a $Z_2\times Z_2$ orbifold that corresponds to a class of realistic free-fermion models. Within the class of interest, we...
Quantum Decoherence in a Four-Dimensional Black Hole Background (1996)
John Ellis, N.E. Mavromatos, D. V. Nanopoulos, Elizabeth Winstanley
We display a logarithmic divergence in the density matrix of a scalar field in the presence of an Einstein-Yang-Mills black hole in four dimensions. This divergence is related to a previously-found...
Constraints From Gauge Coupling Unification On The Scale Of Supersymmetry Breaking (1992)
Ellis, John, Kelley, S., Nanopoulos, D. V.
We reanalyze precision LEP data and coupling constant unification in the minimal supersymmetric $SU(5)$ model including the evolution of the gaugino masses. We derive general bounds on the primordial...