Higgs Decay to Gluons at NNLO

We present an analytical calculation of the next-to-next-to-leading order corrections to the partial decay width $H\to gg$ for a Higgs boson in the intermediate mass range. We apply an asymptotic expansion for $M_H\ll 2M_t$ and compute three terms in the expansion. The leading term confirms the results present in the literature. It is argued that our result is equivalent to an exact calculation up to $M_H\approx M_t$. For a Higgs boson mass of 120 GeV the power-suppressed terms lead to corrections of about 9% in the next-to-next-to-leading order coefficient.Comment: 13 pages, minor corrections, references corrected and added, to be published in Phys. Lett.

On attentional control as a source of residual shift costs: Evidence from two-component task shifts.

It is widely assumed that supervisory or attentional control plays a role only in the preparatory reconfiguration of the mental system in task shifting. The well-known fact that residual shift costs are still present even after extensive preparation is usually attributed to passive mechanisms such as cross talk. The authors question this view and suggest that attentional control is also responsible for residual shift costs. The authors hypothesize that, under shift conditions, tasks are executed in a controlled mode to guarantee reliable performance. Consequently, the control of 2 task components should require more resources than the control of only 1. A series of 4 experiments with 2-component tasks was conducted to test this hypothesis. As expected, more residual shift costs were observed when 2 components rather than 1 varied across trials. Interference effects and sequential effects could not account for these results

Flank instability at Mount Etna: testing the sensitivity of forward models to the internal structure

The deformation recorded at Mount Etna during the last 15 years clearly shows that there is an interplay between activity of magmatic sources and instability of the SE sector. In particular, the anomalous sliding of the SE flank can be triggered by summit or flank eruptions (e.g., 2002), but it is also observed during quiescent loading phases (e.g., 1993-1997). This deformation is usually modeled by sub-horizontal dislocation surfaces (embedded in an elastic half space) whose parameters are determined fitting the observed surface deformation. The purpose of this paper is to investigate whether models forced by a simple isotropic expansion source but taking into account the internal structure of Mount Etna are capable to focus a significant amount of horizontal deformation in the eastern flank. We perform computations based on the finite element method along a 2D cross section. The deformation models include both topography and a synthetic reconstruction of the internal layering constrained by geology, seismic tomography and experimental measurements of Etnean rocks. We study the sensitivity of the predicted surface displacement to variations of internal layers rheology and/or mechanical parameters. Our first results suggest that significant contributions to increase the deformation in the SE sector are due to plastic rheology of the clay layers and to asymmetrical distribution of elastic parameters related to the high velocity body underneath Mount Etna imaged by seismic tomography

Cognitive control modulates preferential sensory processing of affective stimuli

Adaptive human behavior crucially relies on the ability of the brain to allocate resources automatically to emotionally significant stimuli. This ability has consistently been demonstrated by studies showing preferential processing of affective stimuli in sensory cortical areas. It is still unclear, however, whether this putatively automatic mechanism can be modulated by cognitive control processes. Here, we use functional magnetic resonance imaging (fMRI) to investigate whether preferential processing of an affective face distractor is suppressed when an affective distractor has previously elicited a response conflict in a word-face Stroop task. We analyzed this for three consecutive stages in the ventral stream of visual processing for which preferential processing of affective stimuli has previously been demonstrated: the striate area (BA 17), category-unspecific extrastriate areas (BA 18/19), and the fusiform face area (FFA). We found that response conflict led to a selective suppression of affective face processing in category-unspecific extrastriate areas and the FFA, and this effect was accompanied by changes in functional connectivity between these areas and the rostral anterior cingulate cortex. In contrast, preferential processing of affective face distractors was unaffected in the striate area. Our results indicate that cognitive control processes adaptively suppress preferential processing of affective stimuli under conditions where affective processing is detrimental because it elicits response conflict

Stimulation of dorsolateral prefrontal cortex Enhances adaptive cognitive control: a high-definition transcranial direct current stimulation study

Conflict adaptation is a hallmark effect of adaptive cognitive control and refers to the adjustment of control to the level of previously experienced conflict. Conflict monitoring theory assumes that the dorsolateral prefrontal cortex (DLPFC) is causally involved in this adjustment. However,to date, evidence in humans is predominantly correlational, and heterogeneous with respecttothe lateralization of control in the DLPFC. We used high-definition transcranial direct current stimulation (HD-tDCS), which allows for more focal current delivery than conventional tDCS, to clarify the causal involvement of the DLPFC in conflict adaptation. Specifically, we investigated the regional specificity and lateralization of potential beneficial stimulation effects on conflict adaptation during a visual flanker task. One hundred twenty healthy participants were assigned to four HD-tDCS conditions: left or right DLPFC or left or right primary motor cortex (M1). Each group underwent both active and sham HD-tDCS in crossover, double-blind designs. We obtained a sizeable conflict adaptation effect (measured as the modulation of the flanker effect as a function of previous response conflict) in all groups and conditions. However,this effect was larger under active HD-tDCSthan under sham stimulation in both DLPFC groups. In contrast, active stimulation had no effect on conflict adaptation in the M1 groups. In sum, the present results indicate that the DLPFC plays a causal role in adaptive cognitive control, but that the involvement of DLPFC in control is not restricted to the left or right hemisphere. Moreover, our study confirms the potential of HD-tDCS to modulate cognition in a regionally specific manner

The Physics of the B Factories

This work is on the Physics of the B Factories. Part A of this book contains a brief description of the SLAC and KEK B Factories as well as their detectors, BaBar and Belle, and data taking related issues. Part B discusses tools and methods used by the experiments in order to obtain results. The results themselves can be found in Part C