1,721,673 research outputs found
High precision measurement of the form factors of the semileptonic decays K± → π0l±+ν at NA48/2
No full textThe NA48/2 experiment presents preliminary measurements of the form factors of the charged kaon semileptonic decays, based on 4.0 million K e3± and 2.5 million Kμ3 ± decays, both with negligible background. The Ke3 and Kμ3 results are in good agreement allowing for a combined result which matches the precision of the current world average on the vector and scalar form factors. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence
Probing the dark sector with PADME
Full text linkAmong the theoretical models addressing the dark matter problem, the category based on a secluded sector is attracting increasing interest. The PADME experiment, at the Laboratori Nazionali di Frascati (LNF) of INFN, is designed to be sensitive to the production of a low mass gauge boson A of a new U(1) symmetry holding for dark particles. The “dark photon” is weakly coupled to the photon of the Standard Model, and it provides an experimental signature for one of the simplest implementation of the dark sector paradigm. The DAΦNE Beam-Test Facility of LNF will provide a high intensity, mono-energetic positron beam impacting on a low Z target. The PADME detector will measure with high precision the momentum of the photon, produced along with A boson in e + e − annihilation in the target, thus allowing to measure the A mass as the missing mass in the final state. This technique, particularly useful in case of invisible decays of the A boson, will be exploited for the first time in a fixed target experiment. Simulation studies predict a sensitivity on the interaction strength ( 2 parameter) down to 10 −6 , in the mass region 1 MeV< M A < 23.7 MeV, for one year of data taking with a 550 MeV beam. In 2018 the first run will take place, and early data will give the opportunity to compare the detector performance with the design requirements
Status of the PADME experiment and review of dark photon searches
Full text linkWhile accelerator particle physics has traditionally focused on exploring dark matter through highenergy experiments, testing dark-sectors hypothesis requires innovative low energy experiments that use highintensity beams and high-sensitivity detectors. In this scenario attractive opportunities are offered to low energy machines and flavour experiments. In this paper we will focus our attention on the Dark Photon (DP) scenario, reviewing the current status of searches and new opportunities with particular attention to the PADME experiment at Laboratori Nazionali di Frascati
Searching for Light–Dark Matter with Positron Beams
No full textIn the present contribution, we present preliminary ideas on the advantage of using positron beams on fixed target in searching for the Á. In particular, we will discuss Á production mechanisms, accessible only at positron machines, which might offer enhanced cross sections compared to the commonly used Á-strahlung. Recent studies show that the inclusion of such processes in the reinterpretation of old beam dump experiments results in significantly more stringent exclusion limits. Finally, we will discuss the peculiar case of searches for candidates with defined mass, using as a benchmark case the 16.7 MeV X-Boson
Integrating rather than collecting: statistical matching in the data flood era
Full text linkStatistical matching is progressively emerging as a straightforward approach to data integration. This method of increasing importance and interest is useful to address the unsolved challenges posed by data shortage as well as the several opportunities occurring in the present data flood era. This paper offers an exhaustive review of the methodology from its early beginnings up to the most recent developments, considering also the most relevant applications. The links that statistical matching has with other integration methods are discussed, analysing how a 50-year-old method has been only recently proposed under a consistent but (yet) incomplete framework. Strengths and weaknesses of statistical matching are compared, considering different data features and sample representativeness frameworks, also, given future research ideas, always keeping an eye on uncertainty, the key problem to which statistical matching tries to answer
Ten years of bio-based and applied economics: A story of successes, and more to come
Full text linknel paper non è presente l'abstrac
Statistica per l'analisi operativa dei dati
No full textQuante volte non siamo stati in grado di comprendere informazioni di natura statistica? E quante altre, nella lettura di articoli pubblicati su riviste specializzate o di fronte a informazioni diffuse dai mezzi di comunicazione di massa, non ci siamo sentiti all’altezza di interpretarli e valutarli in modo adeguato?
Il volume intende rispondere a queste esigenze e si prefigge la finalità, forse più ambiziosa, di far acquisire al lettore la capacità di produzione ed elaborazione autonoma di dati statistici, attraverso l’applicazione di alcuni degli strumenti che la metodologia statistica mette a disposizione per la descrizione e lo studio quantitativo dei fenomeni collettivi.
Nella trattazione, si è optato per un avvicinamento semplice e immediato alla materia che, pur mantenendo rigore metodologico, privilegia gli aspetti applicativi e il significato del dato con specifico riferimento alla realtà italiana e dei paesi europei
Irrigation reservoirs as blue clubs: Governance and policy intervention
Full text linkReservoirs are increasingly deemed to be important given their potential control of water availability across seasons, from wet to dry seasons, especially given the concerns on the effect of climate change. In this paper, we assess the potential scope for policy intervention on the construction of irrigation reservoirs and its design, focusing on the collective action aspect. We formulate a theoretical model in which farmers pool resources to construct a collective reservoir. We conceptualized the reservoir as a “blue club” that increases the potential water availability in dry season, thus improving water safety for the whole society. We determine the societal potential inefficiency in club size and the policy measures to correct it, focusing on two different club access rules (open vs closed membership). Results show that linear subsidy are ineffective in case of closed membership, and minimum participation rules are required to increase the club size
Agri-environmental Policies and Public Goods: An Assessment of Coalition Incentives and Minimum Participation Rules
No full textAn increasing number of papers analyse the inclusion of collective/spatial conditionality constraints in agricultural policies dealing with natural resource management. In this article we theoretically assess the conditions in which employing collective conditionality constraints linked to incentives better reach the social preferences on PG provision by agriculture. We deal with this issue by using a coalition formation model to endogenize the size of the group of farmers cooperating, and investigate how it is affected by different policy schemes. We analyse and compare the following policy schemes: (1) a homogenous payment that target the whole population of farmers, (2) a coalition bonus, that incentivizes only the contributions by the coalition members, and (3) a coalition bonus associated to a MPR on the size of the coalition. The results show that formulating payments that discriminate between co-operators and free-riders, and associating to such a payment a MPR, is relatively more effective than the traditional homogenous payments. However this is true only under some (local) conditions that we theoretically derived
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