118368961
Non-minimally coupled dark matter: effective pressure and structure formation
We propose a phenomenological model in which a non-minimal coupling between gravity and dark matter is present in order to address some of the apparent small scales issues of ΛCDM model. When described in a frame in which gravity dynamics is given by the standard Einstein-Hilbert action, the non-minimal coupling translates into an effective pressure for the dark matter component. We consider some phenomenological examples and describe both background and linear perturbations. We show that the presence of an effective pressure may lead these scenarios to differ from ΛCDM at the scales where the non-minimal coupling (and therefore the pressure) is active. In particular two effects are present: a pressure term for the dark matter component that is able to reduce the growth of structures at galactic scales, possibly reconciling simulations and observations; an effective interaction term between dark matter and baryons that could explain observed correlations between the two components of the cosmic fluid within Tully-Fisher analysis.
120483563
Framing the dark: theory and phenomenology of a non-minimally coupled dark matter fluid
118311491
Dark matter as a Bose-Einstein Condensate: the relativistic non-minimally coupled case
Bose-Einstein Condensates have been recently proposed as dark matter candidates. In order to characterize the phenomenology associated to such models, we extend previous investigations by studying the general case of a relativistic BEC on a curved background including a non-minimal coupling to curvature. In particular, we discuss the possibility of a two phase cosmological evolution: a cold dark matter-like phase at the large scales/early times and a condensed phase inside dark matter halos. During the first phase dark matter is described by a minimally coupled weakly self-interacting scalar field, while in the second one dark matter condensates and, we shall argue, develops as a consequence the non-minimal coupling. Finally, we discuss how such non-minimal coupling could provide a new mechanism to address cold dark matter paradigm issues at galactic scales.
85534134
Extended LCDM: generalized non-minimal coupling for dark matter fluids
In this paper we discuss a class of models that address the issue of explaining the gravitational dynamics at the galactic scale starting from a geometric point of view. Instead of claiming the existence of some hidden coupling between dark matter and baryons, or abandoning the existence of dark matter itself, we consider the possibility that dark matter and gravity have some non trivial interaction able to modify the dynamics at astrophysical scales. This interaction is implemented assuming that dark matter gets non-minimally coupled with gravity at suitably small scales and late times. After showing the predictions of the model in the Newtonian limit we also discuss the possible origin of it non-minimal coupling. This investigation seems to suggest that phenomenological mechanisms envisaged for the dark matter dynamics, such as the Bose-Einstein condensation of dark matter halos, could be connected to this class of models.
116130873
Measurement of the Transverse Energy Spectrum in Proton-Nucleon Collisions.
120547065
Charmonium states at the Fermilab Antiproton Accumulator. New results from E835
Abstract Experiment E835 has collected a large sample of charmonium states using a hydrogen jet and the virtually monoenergetic stochastically cooled antiproton beam. We present an improved measurement of the ξ c 0 mass and width, preliminary results of analysis of the ξ c 0 decay to μ 0 μ 0 and γγ and the final value of our measurements of the η c parameters.
14624052
Revisiting the formation history of the minor-axis dust lane galaxy NGC 1947
In this paper, we present a detailed study of the peculiar early-type galaxy NGC 1947. The main goal of this work is to constrain the dynamical status and the formation history of NGC 1947 by comparing the observed properties with the predictions derived from different galaxy formation scenarios. To this aim, we derived the photometric and kinematical properties of NGC 1947. Due to the presence of an extended dust lane, which crosses the galaxy centre along the photometric minor axis, we used near-infrared (NIR) images (J and K bands) to derive an accurate analysis of the stellar light distribution. Optical images (in the V and R bands) are used to derive the colour profiles and colour maps to study the structure of the dust lane. The observed kinematics confirm the presence of two components with decoupled angular momentum: gas and dust rotate along the minor axis, while the rotation velocities of the stars are observed along the major axis. The complex structure observed in NGC 1947 supports the hypothesis that some kind of interactions happened in the evolution of this object. We analysed two alternatives: a merging process and an accretion event. We discussed how the observed properties strongly suggest that the decoupled ring of gas and dust has been accreted from outside.
55802943
The shapes of BCGs and normal ellipticals in nearby clusters
We compare the apparent axial ratio distributions of the brightest cluster galaxies (BCGs) and normal ellipticals (Es) in our sample of 75 galaxy clusters from the WIde-field Nearby Galaxy-cluster Survey (WINGS). Most BCGs in our clusters (69 per cent) are classified as cD galaxies. The sample of cDs has been completed by 14 additional cDs (non-BCGs) we found in our clusters. We deproject the apparent axial ratio distributions of Es, BCGs and cDs using a bivariate version of the Lucy rectification algorithm, whose results are supported by an independent Monte Carlo technique. Finally, we compare the intrinsic shape distribution of BCGs to the corresponding shape distribution of the central part of cluster-sized dark matter haloes extracted from the GIF2 Lambda cold dark matter (ΛCDM) N-body simulations (Gao et al.). 
 
 
 
We find that (i) Es have triaxial shape, the triaxiality sharing almost evenly the intrinsic axial ratio parameter space, with a weak preference for prolateness and (ii) the BCGs have triaxial shape as well. However, their tendency towards prolateness is much stronger than in the case of Es. Such a strong prolateness appears entirely due to the sizeable (dominant) component of cDs inside the WINGS sample of BCGs. In fact, while the ‘normal’ (non-cD) BCGs do not differ from Es, as far as the shape distribution is concerned, the axial ratio distribution of BCG_cD galaxies is found to support quite prolate shapes; (iii) our result turns out to be strongly at variance with the only similar previous analysis by Ryden, Lauer & Postman (RLP93), where BCGs and Es were found to share the same axial ratio distribution; (iv) our data suggest that the above discrepancy is mainly caused by the different criteria that RLP93 and ourselves use to select the cluster samples, coupled with a preference of cDs to reside in powerful X-ray-emitting clusters; (v) the GIF2 N-body results suggest that the prolateness of the BCGs (in particular the cDs) could reflect the shape of the associated dark matter haloes.
122241433
A Measurement of the Space - Like Pion Electromagnetic Form-Factor
Abstract The pion form factor has been measured in the space-like q 2 region 0.014 to 0.26 (GeV/ c ) 2 by scattering 300 GeV pions from the electrons of a liquid hydrogen target. A detailed description is given of the apparatus, data analysis and corrections to the data. The mean square charge radius extracted from the data is model-dependent. We find that a form which includes a realistic description of the form factor phase gives a similar results to the naive pole form, and conclude 〈r 2 π 〉 = 0.438±0.008 fm 2 .