889826
Einstein’s Theory of Gravity and the Problem of Missing Mass
Missing Mass Explained? The motion and distribution of galaxies and clusters of galaxies within the universe suggest that there is far more matter than can be seen directly through telescopes. Alternatively, perhaps our understanding of gravity is flawed, leading to a mismatch between the gravitational field inferred from the observed mass distribution in the universe and the observed gravitational field. Ferreira and Starkman (p. 812) review the viability of modifying theories of gravity to solve the problem of missing mass. It emerges that theories of modified gravity remain viable but have become more complex, involving gravitating invisible elements. However, what you see is still not what you get. The observed matter in the universe accounts for just 5% of the observed gravity. A possible explanation is that Newton’s and Einstein’s theories of gravity fail where gravity is either weak or enhanced. The modified theory of Newtonian dynamics (MOND) reproduces, without dark matter, spiral-galaxy orbital motions and the relation between luminosity and rotation in galaxies, although not in clusters. Recent extensions of Einstein’s theory are theoretically more complete. They inevitably include dark fields that seed structure growth, and they may explain recent weak lensing data. However, the presence of dark fields reduces calculability and comes at the expense of the original MOND premise, that the matter we see is the sole source of gravity. Observational tests of the relic radiation, weak lensing, and the growth of structure may distinguish modified gravity from dark matter.
119285987
Cosmology of Axions and Moduli: A Dynamical Systems Approach
xed point attractors, repellers and saddle points, which we analyse in detail. We also provide geometric interpretations of the phase space. The xed points can be used to bound the couplings in the model. A systematic scan of certain regions of parameter space reveals that the future evolution of the universe in this model can be rich, containing multiple epochs of accelerated expansion.
17421918
Living in a void: testing the Copernican principle with distant supernovae.
We show that the local redshift dependence of the luminosity distance can be used to test the Copernican principle that we are not in a central or otherwise special region of the Universe. Future surveys of type Ia supernovae that focus on a redshift range of approximately 0.1-0.4 will be ideally suited to observationally determine the validity of the Copernican principle on new scales, as well as probing the degree to which dark energy must be considered a necessary ingredient in the Universe.
122687802
Imaging the early universe with the BOOMERanG Experiment
The BOOMERanG experiment has recently detected temperature fluctuations the Cosmic Microwave Background (CMB), the otherwise isotropic radiation coming from the early Universe. These anisotropies have a low contrast (about 30 ppm) and feature a peculiar angular power spectrum at angles corresponding to sub-horizon scales at recombination. In the current cosmological model, these structures result from acoustic oscillations in the primeval plasma. In the framework of the Hot Big Bang theory with the inflationary hypothesis, the statistical properties of the image of the CMB allow us to measure most of the cosmological parameters.
36591368
Fast and precise map‐making for massively multi‐detector CMB experiments
Future cosmic microwave background (CMB) polarisation experiments aim to measure an unprecedentedly small signal - the primordial gravity wave component of the polarisation field B-mode. To achieve this, they will analyse huge dataset s, involving years worth of timeordered data (TOD) from massively multi-detector focal planes. This creates the need for fast and precise methods to complement the M-L approach in analysis pipelines. In this paper, we investigate fast map-making methods as applied to long duration, massively multi-detector, ground-based experiments, in the context of the search for B-modes. We focus on two alternative map-making approaches: destriping and TOD filtering , comparing their performance on simulated multi-detector polarisation data. We have written an optimised, parallel destriping code, the DEStriping CARTographer (DESCART), that is generalised for massive focal planes, including the potential effect of cross-correlate d TOD 1/f noise. We also determine the scaling of computing time for destriping as applied to a simulated full-season data-set for a realistic experiment. We find that destriping can out-perf orm filtering in estimating both the large-scale E and B-mode angular power spectra. In particular, filtering can produce significant spurious B-mode power via EB mixing. Whilst this can be removed, it contributes to the variance of B-mode bandpower estimates at scales near the primordial B-mode peak. For the experimental configuration we simulate, this has an effect o n the possible detection significance for primordial B-modes. Destriping is a viable alternative fast method to the full M-L approach that does not cause the problems associated with fil tering, and is flexible enough to
119408227
CMB likelihood functions for beginners and experts
Although the broad outlines of the appropriate pipeline for cosmological likelihood analysis with CMB data has been known for several years, only recently have we had to contend with the full, large-scale, computationally challenging problem involving both highly-correlated noise and extremely large datasets (N>1000). In this talk we concentrate on the beginning and end of this process. First, we discuss estimating the noise covariance from the data itself in a rigorous and unbiased way; this is essentially an iterated minimum-variance mapmaking approach. We also discuss the unbiased determination of cosmological parameters from estimates of the power spectrum or experimental bandpowers.
118913042
Lepton Flavour Violation at the ILC
We explore the possibility of detecting lepton flavour violation, now a well established experimental fact, at the International Linear Collider. Using a model independent approach we conclude that, given all experimental constraints available, there is still room to detect lepton flavour violation at the ILC.
88506479
Parameterizing the flattening of galaxies rotation curves on an expanding locally anisotropic background
In this paper are discussed possible many body generalizations of the expanding locally anisotropic metric ansatz with respect to approximately Newtonian gravitational systems. This ansatz consistently describes local point-like matter distributions on the expanding Universe also allowing for a covariant parameterization of gravitational interactions at intermediate length scales. 
As an example of applicability it is modeled a disk galaxy model matching the physical parameters of the galaxy UGC2885 and it is shown that, by fine-tuning the metric functional parameter, the flattening of the galaxy rotation curve is fully parameterized by this metric. In addition it is numerically computed the mass-energy density corrections due to the expanding anisotropic background and explicitly shown that although there are negative contributions within the galaxy plane the total mass-energy density is strictly positive both at the galaxy plane and outside the galaxy plane. As the functional parameter for this metric is an exponential factor is required a floating point precision of $250$ significant digits for root finding routines and $200$ significant digits to evaluate the effective mass-energy density rendering a final precision of the results presented above double precision ($16$ significant digits). 
It is further shown that these results are consistent with the interpretation of the gravitational corrections as due to Dark Matter, in particular constituting a novel heuristic local parameterization for the Dark Matter distribution within the galaxy plane consistent with both local scale and cosmological scale physical laws which is useful to further investigate the local properties of Dark Matter.
748074
A Pseudo-Photon in Non-Trivial Background Fields
We show that in the presence of external fields for which either Ḃ 6= 0 or ∇ × E 6= 0 it is not possible to derive the classical Maxwell equations from an action with only one gauge field. We suggest that one possible solution is to consider a second physical pseudo-vector gauge field C. The action for this theory is originally motivated by the inclusion of magnetic monopoles. These particles play no role in this work and our argument is only based in, that the violation of the Bianchi identities, cannot be accounted at the action level with only the standard gauge field. We give a particular example for a periodic rotating external magnetic field. Our construction holds that at classical level both the vector and pseudo-vector gauge fields A and C are regular. We compare pseudo-photon with paraphoton (graviphoton) theories concluding that, besides the mechanisms of gauge symmetry already studied by the authors, the Bianchi identities violation are a crucial difference between both theories. We also show that the effects in PVLAS experiment due to the inclusion of pseudo-photons cannot be distinguished from the usual classical induced electric and magnetic fields due to the standard Maxwell equations. Therefore, although this kind of optical experiments cannot test the existence of pseudo-photons, they do not exclude its existence. PACS: ?03.50.De, ?03.70.+k, ?11.15.-q
118891944
Contributions from dimension six strong flavor changing operators to tt plus gauge boson, and t plus Higgs boson production at the CERN LHC
We study the effects of a set of dimension six flavor changing effective operators on several processes of production of top quarks at the LHC. Namely, top anti-top production and associated production of a top and a gauge or Higgs boson. Analytical expressions for the cross sections of these processes are derived and presented.
16906939
Effect of Pions in Cosmic Rays
The effects of pions for vacuum polarization in background magnetic fields are considered. The effects of quark condensates is also briefly addresses. Although these effects are out of the measurement accuracy of laboratory experiments they may be relevant for gamma‐ray burst propagation. In particular, for emissions from the center of the galaxy, we show that the mixing between the neutral pion and photons results in a deviation of the gamma‐ray spectrum from the standard power‐law in the TeV range.