Probability, propensity and probabilities of propensities (and of probabilities)

The process of doing Science in condition of uncertainty is illustrated with a toy experiment in which the inferential and the forecasting aspects are both present. The fundamental aspects of probabilistic reasoning, also relevant in real life applications, arise quite naturally and the resulting discussion among non-ideologized, free-minded people offers an opportunity for clarifications.Comment: Invited contribution to the proceedings MaxEnt 2016 based on the talk given at the workshop (Ghent, Belgium, 10-15 July 2016), supplemented by work done within the program Probability and Statistics in Forensic Science at the Isaac Newton Institute for Mathematical Sciences, Cambridg

Why does the meter beat the second?

Arxiv:physics/0412078 (http://arxiv.org/abs/physics/041207

Talking about Probability, Inference and Decisions. Part 1: The Witches of Bayes

In October 2017 the Italian National Institute of Statistics (ISTAT), Italy's body for official statistics, has published the book of fairy tales Le streghe di Bayes (The witches of Bayes) written by ISTAT staff members with the commendable aim of introducing statistical and probabilistic reasoning to children. In this paper the fairy tale which gives the name to the book is analyzed in a dialog between three teachers with different background and expertise. The outcomes are definitively discouraging, especially when the story is compared to the appendix of the book, in which the teaching power of every story is indeed explained (as a matter of fact, without the appendix the fairy tale of the witches seemed to be written with the purpose of make the 'Bayesians', meant as the villagers from 'Bayes', ridiculous). In fact the fairy tale of the witches does not contain any Bayesian reasoning, the suggested decision strategy is simply wrong and the story does not even seem to be easily modifiable (besides the trivial correction of the decision strategy) in order to make it usable as a teaching tool. As it happens in real dialogues, besides the fairy tale in question, the dialogue touches several issues somehow related to the story and concerning probability, inference, prediction and decision making. The present paper is an indirect response to the invitation by the ISBA bulletin to comment on the fairy tale.Comment: 48 pages, 14 figures, in Italian, be published in Progetto Alice, Rivista di matematica e didattic

Search for heavy neutral lepton production in K+ decays

A search for heavy neutral lepton production in K + decays using a data sample collected with a minimum bias trigger by the NA62 experiment at CERN in 2015 is reported. Upper limits at the 10−7 to 10−6 level are established on the elements of the extended neutrino mixing matrix |Ue4| 2 and |Uμ4| 2 for heavy neutral lepton mass in the ranges 170–448 MeV/c2 and 250–373 MeV/c2, respectively. This improves on the previous limits from HNL production searches over the whole mass range considered for |Ue4|2 and above 300 MeV/c2 for |Uμ4|2