相关论文: Extra Dimensions in the Early Universe
The metal-poor damped Lyman alpha (DLA) system at z = 3.04984 in the QSO SDSSJ1419+0829 has near-ideal properties for an accurate determination of the primordial abundance of deuterium, (D/H)_p. We have analysed a high-quality spectrum of…
Since the dawn of the new millennium, there has been a revived interest in the concept of extra dimensions.In this scenario all the standard model matter and gauge fields are confined to the 4 dimensions and only gravity can escape to…
Quasar absorption spectral data indicate the presence of a spatial gradient in the electromagnetic fine-structure constant $\alpha$ on cosmological length scales. We point out that experiments with accelerometers, including torsion pendula…
In this paper we propose that the accelerating expansion of the present matter-dominated universe, as suggested by the recent distance measurements of type Ia supernovae, is generated along with the evolution of space in extra dimensions.…
It has recently been proposed that the Universe might be accelerating as a consequence of extra dimensions with time varying size. We show that although these scenarios can lead to acceleration, they run into serious difficulty when taking…
A comparison between the line of sight power spectrum of absorption in the Lyman-alpha forest and the cross power spectrum between the absorption in neighboring lines of sight offers an evolution-free means to constrain the cosmological…
The relic cosmic background neutrinos accompanying the cosmic microwave background (CMB) photons may hide a universal lepton asymmetry orders of magnitude larger than the universal baryon asymmetry. At present, the only direct way to probe…
We report on a search for large extra dimensions in a data sample of approximately 1 fb^{-1} of ppbar collisions at sqrt(s) = 1.96 TeV. We investigate Kaluza-Klein graviton production with a photon and missing transverse energy in the final…
This article critically reviews the proposal for addressing the cosmological constant problem within the framework of supersymmetric large extra dimensions (SLED), as recently proposed in hep-th/0304256. After a brief restatement of the…
It is intriguing to consider the possibility that the Big Bang of the standard (3+1) dimensional cosmology originated from the collision of two branes within a higher dimensional spacetime, leading to the production of a large amount of…
The recent up to 2fb^{-1} of data from the ATLAS and CMS experiments at the CERN Large Hadron Collider at 7TeV put an upper bound on the production cross section of a Higgs-like particle. We translate the results of the H -> WW -> l nu l nu…
We present a new approach to early universe cosmology. Inflation is replaced by a phase transition in which both matter and geometry are created simultaneously. We calculate the spectrum of metric perturbations and show that it is flat. We…
We propose an interpretation of the diboson excess recently observed by the ATLAS and CMS collaborations in terms of Kaluza-Klein excitations of electroweak gauge bosons stemming from a realization of a warped extra-dimensional model that…
The lepton asymmetry of order one is not excluded experimentally and, if present, can lead to interesting phenomena in the early Universe. It is shown that, when the temperature is above the quark-hadron transition, the lepton asymmetry…
The evolution of the Universe is the ultimate laboratory to study fundamental physics across energy scales that span about 25 orders of magnitude: from the grand unification scale through particle and nuclear physics scales down to the…
The emphasis in the developmet of theories with more than three spatial dimensions has recently shifted towards ``brane world'' picture, which assumes that ordinary matter (with possible exceptions of gravitons and other, hypothetic,…
We searched for star formation activity associated with high-z Damped Lyman-alpha systems (DLAs) with Subaru telescope. We used a set of narrow-band (NB) filters whose central wavelengths correspond to the redshifted Lyman-alpha emission…
We discuss the present bounds on the relativistic energy density in the Universe parameterized in terms of the effective number of neutrinos N using the most recent cosmological data on Cosmic Microwave Background (CMB) temperature…
Theories of large extra dimensions (LEDs) such as the Arkani-Hamed, Dimopoulos & Dvali scenario predict a "true" Planck scale $M_\star$ near the TeV scale, while the observed $M_{pl}$ is due to the geometric effect of compact extra…
We explore the possibility that color symmetry SU(3) was not an exact symmetry at all times in the early universe, using minimal extensions of the standard model that contain a color triplet scalar field and perhaps other fields. We show…