Light neutralino dark matter in MSSM

Three dark matter direct detection experiments, DAMA, COGENT and CRESST, have reported a possible signal of WIMP interaction corresponding to very light particles, close to the edge of the XENON 100 and CDMS sensitivity. Imposing the latest constraints from colliders, flavour physics, electroweak precision tests and direct and indirect dark matter searches, we show that viable MSSM scenarios with a light neutralino, in agreement with all the present data, are feasible. An analysis of the characteristics of the resulting scenarios will be presented.Comment: 6 pages, 2 figures, contribution to the ICHEP 2012 Conference proceedings, 4-11 July 2012, Melbourne, Australi

Implications of LHC Higgs and SUSY searches for MSSM

The implications of the LHC SUSY searches as well as the discovery of a new bosonic state compatible with the lightest Higgs boson will be discussed in the context of constrained and general MSSM scenarios. Exploring the MSSM through the Higgs sector is an alternative and complementary path to direct searches, and tight constraints on the MSSM parameter space can be obtained.Comment: 7 pages, 5 figures, contribution to the ICHEP 2012 Conference proceedings, 4-11 July 2012, Melbourne, Australi

An update of the constraints on the phenomenological MSSM from the new LHC Higgs results

Updated results on the search of Higgs bosons at the LHC with up to 17/fb of data have just been presented by the ATLAS and CMS collaborations. New constraints are provided by the LHCb and XENON experiments with the observation of the rare decay B_s -> mu+mu- and new limits on dark matter direct detection. In this paper, we update and extend the results on the implications of these data on the phenomenological Minimal Supersymmetric extension of the Standard Model (pMSSM) by using high statistics, flat scans of its 19 parameters. The new LHC data on bb and tau tau decays of the lightest Higgs state and the new CMS limits from the tau tau searches for the heavier Higgs states set stronger constraints on the pMSSM parameter space.Comment: 14 pages, 8 figures. This update is based on results presented at HCP 2012 and the December 2012 CERN Council LHC Jamboree. It features larger scan statistics and additional plot

Two brains in action: joint-action coding in the primate frontal cortex

Daily life often requires the coordination of our actions with those of another partner. After sixty years (1968-2018) of behavioral neurophysiology of motor control, the neural mechanisms which allow such coordination in primates are unknown. We studied this issue by recording cell activity simultaneously from dorsal premotor cortex (PMd) of two male interacting monkeys trained to coordinate their hand forces to achieve a common goal. We found a population of 'joint-action cells' that discharged preferentially when monkeys cooperated in the task. This modulation was predictive in nature, since in most cells neural activity led in time the changes of the "own" and of the "other" behavior. These neurons encoded the joint-performance more accurately than 'canonical action-related cells', activated by the action per se, regardless of the individual vs. interactive context. A decoding of joint-action was obtained by combining the two brains activities, using cells with directional properties distinguished from those associated to the 'solo' behaviors. Action observation-related activity studied when one monkey observed the consequences of the partner's behavior, i.e. the cursor's motion on the screen, did not sharpen the accuracy of 'joint-action cells' representation, suggesting that it plays no major role in encoding joint-action. When monkeys performed with a non-interactive partner, such as a computer, 'joint-action cells' representation of the "other" (non-cooperative) behavior was significantly degraded. These findings provide evidence of how premotor neurons integrate the time-varying representation of the self-action with that of a co-actor, thus offering a neural substrate for successful visuo-motor coordination between individuals.SIGNIFICANT STATEMENTThe neural bases of inter-subject motor coordination were studied by recording cell activity simultaneously from the frontal cortex of two interacting monkeys, trained to coordinate their hand forces to achieve a common goal. We found a new class of cells, preferentially active when the monkeys cooperated, rather than when the same action was performed individually. These 'joint-action neurons' offered a neural representation of joint-behaviors by far more accurate than that provided by the canonical action-related cells, modulated by the action per se regardless of the individual/interactive context. A neural representation of joint-performance was obtained by combining the activity recorded from the two brains. Our findings offer the first evidence concerning neural mechanisms subtending interactive visuo-motor coordination between co-acting agents

Strong boards, ownership concentration and EU banks' systemic risk-taking: Evidence from the financial crisis

We examine the effects of board composition and ownership on traditional measures of bank risk and proxies of bank tail and systemic risk. Both banks’ corporate governance shortcomings and systemic risk-taking have been recognized among the potential causes of the 2007 financial crisis. Yet, their interaction has received less attention so far. Based on a sample of 40 European banks over the period 2006–2010, we find that the boards ‘characteristics affect banks’ systemic risk, except for board independence and that this relation depends on capital regulations, banking systems’ ownership structures and bank activity restrictions

Effects of Universal Extra Dimensions on Higgs signals at LHC

A major focus at the Large Hadron Collider (LHC) will be Higgs boson studies and it would be an interesting prospect to simultaneously probe for physics beyond the Standard Model (SM) in the Higgs signals. In this work we show as to what extent, the effects of Universal Extra Dimension (UED) can be isolated at the LHC through the Higgs signals. By doing a detailed study of the different uncertainties involved in the measurement of the rates for the process pp --> h --> gamma gamma we estimate the extent to which these uncertainties can mask the effects of the contributions coming from UED.Comment: 13 pages, LateX, Title changed, text and figures modified. Version to appear in IJMP

Theoretical study of turbulent channel flow: Bulk properties, pressure fluctuations, and propagation of electromagnetic waves

In this paper, we apply two theoretical turbulence models, DIA and the recent GISS model, to study properties of a turbulent channel flow. Both models provide a turbulent kinetic energy spectral function E(k) as the solution of a non-linear equation; the two models employ the same source function but different closures. The source function is characterized by a rate n sub s (k) which is derived from the complex eigenvalues of the Orr--Sommerfeld (OS) equation in which the basic flow is taken to be of a Poiseuille type. The O--S equation is solved for a variety of Reynolds numbers corresponding to available experimental data. A physical argument is presented whereby the central line velocity characterizing the basic flow, U0 sup L, is not to be identified with the U0 appearing in the experimental Reynolds number. The theoretical results are compared with two types of experimental data: (1) turbulence bulk properties, and (2) properties that depend stongly on the structure of the turbulence spectrun at low wave numbers. The only existing analytical expression for Pi (k) cannot be used in the present case because it applies to the case of a flat plate, not a finite channel

The extended structure of the dwarf irregular galaxy Sagittarius

We present a detailed study of the stellar and HI structure of the dwarf irregular galaxy Sagittarius. We use new deep and wide field photometry to trace the surface brightness profile of the galaxy out to ~5.0' (corresponding to ~1600 pc) and down to $\mu_V\simeq 30.0$ mag/arcsec$^2$, thus showing that the stellar body of the galaxy is much more extended than previously believed, and it is similarly (or more) extended than the overall HI distribution. The whole major-axis profile is consistent with a pure exponential, with a scale radius of $\simeq 340$ pc. The surface density maps reveal that the distribution of old and intermediate-age stars is smooth and remarkably flattened out to its edges, while the associated HI has a much rounder shape, is off-centred and presents multiple density maxima and a significant hole. No clear sign of systemic rotation is detectable in the complex HI velocity field. No metallicity gradient is detected in the old and intermediate age population of the galaxy, and we confirm that this population has a much more extended distribution than young stars (age$\lt 1$ Gyr).Comment: 11 pages, 14 figures, accepted for publication on A&A. arXiv admin note: text overlap with arXiv:1404.169