0000000001052459
AUTHOR
A Parenti
Search for K+ decays to a muon and invisible particles
The NA62 experiment at CERN reports searches for $K^+\to\mu^+N$ and $K^+\to\mu^+\nu X$ decays, where $N$ and $X$ are massive invisible particles, using the 2016-2018 data set. The $N$ particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of ${\cal O}(10^{-8})$ of the neutrino mixing parameter $|U_{\mu4}|^2$ for $N$ masses in the range 200-384 MeV/$c^2$ and lifetime exceeding 50 ns. The $X$ particle is considered a scalar or vector hidden sector mediator decaying to an invisible final state, and upper limits of the decay branching fraction for $X$ masses in the range 10-370 MeV/$c^2$ are reported for the first time, ranging from ${\cal O}(10^{-5})$ t…
Productivity Dynamics across European Regions: the Impact of Structural and Cohesion Funds
This paper analyzes the impact of the European Union regional policy of the three programming periods 1975-1988, 1989-1993 and 1994-1999 on the dynamics of productivity of European regions. On average, funding had a positive, but concave, effect on productivity growth. In particular, a share of funds on GVA of 10% GVA is estimated to raise the regional growth rate of about 0.9% per year. However, by separately considering the three programming periods and the composition of the funds according to the objectives defined by the EU, we find that: i) only the funds allocated in the second and third programming periods, when they remarkably increased, had a significant impact; and ii) only Objective…