Optimizing momentum resolution with a new fitting method for silicon-strip detectors

A new fitting method is explored for momentum reconstruction of tracks in a constant magnetic field for a silicon-strip tracker. Substantial increases of momentum resolution respect to standard fit is obtained. The key point is the use of a realistic probability distribution for each hit (heteroscedasticity). Two different methods are used for the fits, the first method introduces an effective variance for each hit, the second method implements the maximum likelihood search. The tracker model is similar to the PAMELA tracker. Each side, of the two sided of the PAMELA detectors, is simulated as momentum reconstruction device. One of the two is similar to silicon micro-strip detectors of large use in running experiments. Two different position reconstructions are used for the standard fits, the $\eta$-algorithm (the best one) and the two-strip center of gravity. The gain obtained in momentum resolution is measured as the virtual magnetic field and the virtual signal-to-noise ratio required by the two standard fits to reach an overlap with the best of two new methods. For the best side, the virtual magnetic field must be increased 1.5 times respect to the real field to reach the overlap and 1.8 for the other. For the high noise side, the increases must be 1.8 and 2.0. The signal-to-noise ratio has similar increases but only for the $\eta$-algorithm. The signal-to-noise ratio has no effect on the fits with the center of gravity. Very important results are obtained if the number N of detecting layers is increased, our methods provide a momentum resolution growing linearly with N, much higher than standard fits that grow as the $\sqrt{N}$.Comment: This article supersedes arXiv:1606.03051, 22 pages and 10 figure

Effect of a realistic three-body force on the spectra of medium-mass hypernuclei

We adopt the Hartree-Fock (HF) method in the proton-neutron-$\Lambda$ (p-n-$\Lambda$) formalism and the nucleon-$\Lambda$ Tamm-Dancoff Approximation (N$\Lambda$ TDA) to study the energy spectra of medium-mass hypernuclei. The formalism is developed for a potential derived from effective field theories which includes explicitly the 3-body $NNN$ forces plus the $YN$ LO potential. The energy spectra of selected medium-mass hypernuclei are presented and their properties discussed. The present calculation is the first step of a project devoted to {\it ab initio} studies of hypernuclei in medium and heavy mass regions. This may provide a guide for a better understanding of the $YN$ interactions at momentum scales not accessible in few-body hypernuclei.Comment: 7 pages, 9 figures, accepted in Physica Script

Digital Constitutionalism in Europe

This book provides the first study on digital constitutionalism in Europe. The research explains the European constitutional reaction to the challenges of digital capitalism while exploring a normative perspective to protect fundamental rights and democracy in the algorithmic society based on the path of European digital constitutionalism

The rise of digital constitutionalism in the European Union

Abstract In the last twenty years, the policy of the European Union in the field of digital technologies has shifted from a liberal economic perspective to a constitution-oriented approach. This change of heart has resulted primarily from the rise of the information society which has created not only new opportunities but also challenges to fundamental rights and democratic values. Even more importantly, this technological framework driven by liberal ideas has empowered transnational corporations operating in the digital environment to perform quasi-public functions on a global scale. This article analyzes the path and the reasons that have led the European Union to enter a new phase of modern constitutionalism (i.e. digital constitutionalism). The primary goal of this article is to describe the characteristics of this new constitutional phase opposing platform powers, and to outline the potential evolution of European digital constitutionalism in the global context