arXiv subjects

Mauro Mezzetto

Publications and source records attributed to Mauro Mezzetto.

11 recordsLinked to original sources

arXiv2024

A statistical model to identify excess mortality in Italy in the period 2011-2022

Excess mortality is defined as an increase in the number of deaths above what is expected based on historical trends, hereafter called baseline. In a previous paper, we introduced a statistical method that allows an unbiased and robust determination of the baseline to be used for the computation of excesses. A good determination of the baseline allows us to efficiently evaluate the excess of casualties that occurred in Italy in the last 12 years and in particular in the last 3 years due to the Coronavirus Disease 2019 (COVID-19) epidemic. To this extent, we have analyzed the data on mortality in Italy in the period January 1st 2011 to December 31th 2022, provided by the Italian National Institute of Statistics (ISTAT). The dataset contains information on deaths for all possible causes, without specific reference to any particular one. The data exhibit strikingly evident periodicity in the number of deaths with pronounced maxima in the winter and minima in the summer, repeating itself in amplitude along the whole twelve-year sample. Superimposed on this wave-like structure are often present excesses of casualties, most likely due to occasional causes of death such as the flu epidemics (in winter) and heat waves (in summer). The very accurate periodicity along the seasons (the "baseline"), allows us to determine with great accuracy and confidence the number of expected deaths for each day of the year in the absence of occasional contributions. Each of the latter can be modeled with an additional function that parameterizes the deviation from the baseline.

physics.med-ph↗

arXiv2021

Study on the effects of the restrictive measures for containment of the COVID-19 pandemic on the reproduction number $R_t$ in Italian regions

Since November 6$^{\mathrm{th}}$, 2020, Italian regions have been classified according to four levels, corresponding to specific risk scenarios, for which specific restrictive measures have been foreseen. By analyzing the time evolution of the reproduction number $R_t$, we estimate how much different restrictive measures affect $R_t$, and we quantify the combined effect of the diffusion of virus variants and the beginning of the vaccination campaign upon the $R_t$ trend. We also compute the time delay between implementation of restrictive measures and the resulting effects. Three different models to describe the effects of restrictive measures are discussed and the results are cross-checked with two different algorithms for the computation of $R_t$.

physics.soc-ph↗

arXiv2021

A simplified estimate of the Effective Reproduction Number $R_t$ using its relation with the doubling time and application to Italian COVID-19 data

A simplified method to compute $R_t$, the Effective Reproduction Number, is presented. The method relates the value of $R_t$ to the estimation of the doubling time performed with a local exponential fit. The condition $R_t = 1$ corresponds to a growth rate equal to zero or equivalently an infinite doubling time. Different assumptions on the probability distribution of the generation time are considered. A simple analytical solution is presented in case the generation time follows a gamma distribution.

physics.soc-ph↗

arXiv2021

A statistical analysis of death rates in Italy for the years 2015-2020 and a comparison with the casualties reported for the COVID-19 pandemic

We analyze the data about casualties in Italy in the period 01/01/2015 to 30/09/2020 released by the Italian National Institute of Statistics (ISTAT). The data exhibit a clear sinusoidal behavior, whose fit allows for a robust subtraction of the baseline trend of casualties in Italy, with a surplus of mortality in correspondence to the flu epidemics in winter and to the hottest periods in summer. While these peaks are symmetric in shape, the peak in coincidence with the COVID-19 pandemics is asymmetric and more pronounced. We fit the former with a Gaussian function and the latter with a Gompertz function, in order to quantify number of casualties, the duration and the position of all causes of excess deaths. The overall quality of the fit to the data turns out to be very good. We discuss the trend of casualties in Italy by different classes of ages and for the different genders. We finally compare the data-subtracted casualties as reported by ISTAT with those reported by the Italian Department for Civil Protection (DPC) relative to the deaths directly attributed to COVID-19, and we discuss the differences.

physics.soc-ph↗

arXiv2021

A study on the possible merits of using symptomatic cases to trace the development of the COVID-19 pandemic

In a recent work we introduced a novel method to compute the effective reproduction number $R_t$ and we applied it to describe the development of the COVID-19 outbreak in Italy. The study is based on the number of daily positive swabs as reported by the Italian Dipartimento di Protezione Civile. Recently, the Italian Istituto Superiore di Sanità made available the data relative of the symptomatic cases, where the reporting date is the date of beginning of symptoms instead of the date of the reporting of the positive swab. In this paper we will discuss merits and drawbacks of this data, quantitatively comparing the quality of the pandemic indicators computed with the two samples.

physics.soc-ph↗

arXiv2012

European Strategy for Accelerator-Based Neutrino Physics

Massive neutrinos reveal physics beyond the Standard Model, which could have deep consequences for our understanding of the Universe. Their study should therefore receive the highest level of priority in the European Strategy. The discovery and study of leptonic CP violation and precision studies of the transitions between neutrino flavours require high intensity, high precision, long baseline accelerator neutrino experiments. The community of European neutrino physicists involved in oscillation experiments is strong enough to support a major neutrino long baseline project in Europe, and has an ambitious, competitive and coherent vision to propose. Following the 2006 European Strategy for Particle Physics (ESPP) recommendations, two complementary design studies have been carried out: LAGUNA/LBNO, focused on deep underground detector sites, and EUROnu, focused on high intensity neutrino facilities. LAGUNA LBNO recommends, as first step, a conventional neutrino beam CN2PY from a CERN SPS North Area Neutrino Facility (NANF) aimed at the Pyhasalmi mine in Finland. A sterile neutrino search experiment which could also be situated in the CERN north area has been proposed (ICARUS-NESSIE) using a two detector set-up, allowing a definitive answer to the 20 year old question open by the LSND experiment. EUROnu concluded that a 10 GeV Neutrino Factory, aimed at a magnetized neutrino detector situated, also, at a baseline of around 2200 km (+-30%), would constitute the ultimate neutrino facility; it recommends that the next 5 years be devoted to the R&D, preparatory experiments and implementation study, in view of a proposal before the next ESPP update. The coherence and quality of this program calls for the continuation of neutrino beams at CERN after the CNGS, and for a high priority support from CERN and the member states to the experiments and R&D program.

hep-ex↗

arXiv2010

Theta_13: phenomenology, present status and prospect

The leptonic mixing angle theta_13 is currently a high-priority topic in the field of neutrino physics, with five experiments under way, searching for neutrino oscillations induced by this angle. We review the phenomenology of theta_13 and discuss the information from present global oscillation data. A description of the upcoming reactor and accelerator experiments searching for a non-zero value of theta_13 is given, and we evaluate the sensitivity reach within the next few years.

hep-ph↗

arXiv2009

Next Challenge in Neutrino Physics: the theta(13) Angle

A new generation of oscillation experiments optimized to measure theta(13) is ready to start. Performances, complementarity and competition of these accelerator and reactor experiments will be shortly illustrated. The capability of measuring theta(13) with other neutrino sources, like solar, atmospheric, supernovae neutrinos or neutrinos from a tritium source will be discussed too.

hep-ph↗

arXiv2008

On the impact of systematical uncertainties for the CP violation measurement in superbeam experiments

Superbeam experiments can, in principle, achieve impressive sensitivities for CP violation in neutrino oscillations for large $θ_{13}$. We study how those sensitivities depend on assumptions about systematical uncertainties. We focus on the second phase of T2K, the so-called T2HK experiment, and we explicitly include a near detector in the analysis. Our main result is that even an idealised near detector cannot remove the dependence on systematical uncertainties completely. Thus additional information is required. We identify certain combinations of uncertainties, which are the key to improve the sensitivity to CP violation, for example the ratio of electron to muon neutrino cross sections and efficiencies. For uncertainties on this ratio larger than 2%, T2HK is systematics dominated. We briefly discuss how our results apply to a possible two far detector configuration, called T2KK. We do not find a significant advantage with respect to the reduction of systematical errors for the measurement of CP violation for this setup.

hep-ph↗

arXiv2003

Beta-Beams: present design and expected performances

We give the present status of the beta-beam study, which aims at producing intense nue and antinue beams from the decay of relativistic radioactive io ns. The emphasis is put on recent technical progress and new ideas. The expected performances in terms of neutrino mixing parameters theta13 and CP violating phase delta using a megaton water Cerenkov detector installed in the Frejus underground laboratory are shown to be excellent, and the synergy with a a companion SuperBeam is underlined.

hep-ex↗

arXiv2003

Physics Reach of the Beta Beam

Beta Beams are designed to produce pure (anti)electron neutrino beams and could be an elegant and powerful option for the search of leptonic CP violating processes. In this paper will be quantified the physics reach of a CERN based Beta Beam and of a Super Beam - Beta Beam combination. The CP phase $δ$ sensitivity results to be comparable to a Neutrino Factory for $\sin^2{θ_{13}}$ values greater than $10^{-4}$.

hep-ex↗