Stress-sensitive inference of task controllability

ABSTRACTEstimating environmental controllability enables agents to better predict upcoming events and decide when to engage controlled action selection. How does the human brain estimate environmental controllability? Trial-by-trial analysis of choices, decision times and neural activity in an explore-and-predict task demonstrate that humans solve this problem by comparing the predictions of an “actor” model with those of a reduced “spectator” model of their environment. Neural BOLD responses within striatal and medial prefrontal areas tracked the instantaneous difference in the prediction errors generated by these two statistical learning models. BOLD activity in the posterior cingulate, parietal and prefrontal cortices covaried with changes in estimated controllability. Exposure to inescapable stressors biased controllability estimates downward and increased reliance on the spectator model in an anxiety-dependent fashion. Taken together, these findings provide a mechanistic account of controllability inference and its distortion by stress exposure.

T-odd generalized and quasi transverse momentum dependent parton distribution in a scalar spectator model

Generalized transverse momentum dependent parton distributions (GTMDs), as mother funtions of transverse momentum dependent parton distributions (TMDs) and generalized parton distributions (GPDs), encode the most general parton structure of hadrons. We calculate four twist-two time reversal odd GTMDs of pion in a scalar spectator model. We study the dependence of GTMDs on the longitudinal momentum fraction x carried by the active quark and the transverse momentum $$|\vec k_T|$$ | k → T | for different values of skewness $$\xi $$ ξ defined as the longitudinal momentum transferred to the pion as well as the total momentum $$|\vec \Delta _T|$$ | Δ → T | transferred to the pion. In addition, the quasi-TMDs and quasi-GPDs of pion have also been investigated in this paper.

Semi-leptonic decays of a particle to three bodies

Is presented the dynamics and kinematics of the semi-leptonic decays with interaction V-A calculating the decay width and the fraction of decay for each process using spectator model. The results are compared with the experimental data of the table particle data group, which show that the model prediction for this type of decay can be considered as a first approximation. This type of analysis is particularly important because it allows one hand, introduce to the beginner students to the study of particle physics and on the other gives the possibility to use strategies to address topics modern in physics courses at university level.