NA48/2 studies of rare decays

The first observation of about 2000 candidates, with a background contamination below 3%, of the rare decay $K^{\pm} \to \pi^{\pm}\pi^{0}e^+e^-$ is reported by the NA48/2 experiment. The preliminary branching ratio in the full kinematic region is obtained to be: ${\cal B}(K^{\pm} \to \pi^{\pm}\pi^{0}e^+e^-)=(4.06\pm0.17)\cdot10^{-6}$ by analyzing the data collected in 2003. A sample of $4.687\times 10^6$ $K^\pm\to\pi^\pm\pi^0_D$, decay candidates with a negligible background contamination collected in 2003-04 is analyzed to search for the dark photon ($A'$) via the decay chain $K^\pm\to\pi^\pm\pi^0$, $\pi^0\to\gamma A'$, $A'\to e^+e^-$. No signal is observed, and preliminary limits in the plane dark photon mixing parameter $\varepsilon^2$ versus its mass $m_{A'}$ are reported.Comment: To be published in La Thuile 2015 proceedings. arXiv admin note: text overlap with arXiv:1412.805

Time over threshold in the presence of noise

The time over threshold is a widely used quantity to describe signals from various detectors in particle physics. Its electronics implementation is straightforward and in this paper we present the studies of its behavior in the presence of noise. A unique comb-like structure was identified in the data for a first time and was explained and modeled successfully. The effects of that structure on the efficiency and resolution are also discussed.Comment: 6 pages, 8 figure

The PADME experiment at LNF

The PADME experiment, approved by INFN at the end of 2015, aims to search for missing mass signals in the annihilation of positrons on a thin fixed target produced by invisible decays of the dark photon. The detector construction will be completed by the end of 2017 to be ready to run in spring of 2018. The collaboration aims at collecting about 1013 positron on target by the end of 2018 to reach a sensitivity down to 1 × 10−3 on the coupling of A′ up to 23.7 MeV mass

Cooperative Management of Ecosystem Services: Coalition Formation, Landscape Structure and Policies

A growing body of literature shows that full-cooperation among farmers to manage productive ecosystem services would yield gains with respect to uncoordinated approaches. The public good feature of these ecosystem services may, however, hinder the emergence of a cooperative solution at the landscape scale. In this paper, we introduce in a coalition formation game a spatially-explicit bioeconomic model of fruit pollination, where pollinaton depends on the distance to the choosen location of natural habitats. We analyse: (i) which coalitions are stable; (ii) what benefits they provide; (iii) how cooperation depends on the initial landscape structure; and (iv) how policy instruments affect cooperation. The theoretical model presents the rationality of cooperation but, due to the detailed heterogeneity and complex spatial interactions among farms, we use a numerical example to determine the stable coalitions. We find that only small coalitions are stable and that the benefits of cooperation decrease when the spatial autocorrelation of fruit tree covers increase. Policy instruments can increase the interest for cooperation but per-hectare payments and minimum participation rules may reduce the habitat area at the margin (by decreasing the stability of coalitions). Price premium for the coalition members increase the habitat area but its budget-effectiveness decreases as the spatial autocorrelation of fruit tree covers increase

Evidence that muscle cells do not express the histidine-rich glycoprotein associated with AMP deaminase but can internalise the plasma protein

Histidine-rich glycoprotein (HRG) is synthesized by liver and is present at relatively high concentration in the plasma of vertebrates. We have previously described the association of a HRG-like molecule to purified rabbit skeletal muscle AMP deaminase (AMPD). We also provided the first evidence for the presence of a HRG-like protein in human skeletal muscle where a positive correlation between HRG content and total determined AMPD activity has been shown. In the present paper we investigate the origin of skeletal muscle HRG. The screening of a human skeletal muscle cDNA expression library using an anti-HRG antibody failed to reveal any positive clone. The RT-PCR analysis, performed on human skeletal muscle RNA as well as on RNA from the rhabdomyosarcoma (RD) cell line, failed to show any mRNA specific for the plasma HRG or for the putative muscle variant. When the RD cells were incubated with human plasma HRG, a time-dependent increase of the HRG immunoreactivity was detected both at the plasma membrane level and intracellularly. The internalisation of HRG was inhibited by the addition of heparin. The above data strongly suggest that skeletal muscle cells do not synthesize the muscle variant of HRG but instead can actively internalise it from plasma

Probing the dark sector with PADME

Among 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 (l2 parameter) down to 10−6, in the mass region 1MeV<MA' < 23.7MeV, for one year of data taking with a 550MeV 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

GEANT4-based full simulation of the PADME experiment at the DAΦNE BTF

A possible solution to the dark matter problem postulates that dark particles can interact with Standard Model particles only through a new force mediated by a “portal”. If the new force has a U(1) gauge structure, the “portal” is a massive photon-like vector particle, called dark photon or A′. The PADME experiment at the DAΦNE Beam-Test Facility (BTF) in Frascati is designed to detect dark photons produced in positron on fixed target annihilations decaying to dark matter (e+e-→γA′) by measuring the final state missing mass. The experiment will be composed of a thin active diamond target where a 550 MeV positron beam will impinge to produce e+e- annihilation events. The surviving beam will be deflected with a magnet while the photons produced in the annihilation will be measured by a calorimeter composed of BGO crystals. To reject the background from Bremsstrahlung gamma production, a set of segmented plastic scintillator vetoes will be used to detect positrons exiting the target with an energy lower than that of the beam, while a fast small angle calorimeter will be used to reject the e+e-→γγ(γ) background. To optimize the experimental layout in terms of signal acceptance and background rejection, the full layout of the experiment was modelled with the GEANT4 simulation package. In this paper we will describe the details of the simulation and report on the results obtained with the software

Ambiguity, Familiarity and Learning Behavior in the Adoption of ICT for Irrigation Management

Subjective behavior of decision makers (DMs) is paramount when modeling information and communication technology (ICT) adoption choices in irrigated agriculture. Here, efficient ICT aided irrigation plans often involve a certain degree of uncertainty, and differential attitudes toward it can cause uncoordinated actions between actors. Some DMs will implement ICT information, while others will not because they do not trust ICT reliability. This risks undermining the achievement of ICT benefits in terms of water saving at the irrigation district level. By distinguishing between differ ent sources of uncertainty, taking the form of risk and ambiguity, in the present paper, we developed a new decision model to assess the impact that subjective behavior and learning processes have on the efficiency of ICT-aided irrigation plans. A case study was selected to implement the model in simplified settings. The results revealed the potential of ambiguity to limit ICT information implemen tation and to hinder water governance. Implications mainly concern the development of uncertainty management policies to favor DMs becoming familiar with the new ICT with lower ambiguit

Implementation of the Water Framework Directive in Italy: state of the art and selected research issues

The Water Framework Directive (WFD) was implemented rather late in Italy. The actual implementation took place in 2006 with decree 152/2006 but the Directive was not completely effective until the beginning of 2009, when law 13/2009 provided for the implementation of river basin plans by basin authorities. The objective of this paper is to describe the implementation of the WFD in Italy and to discuss selected policy and research issues. The paper begins with an introduction highlighting the specificities of Italy in terms of water management. With regard to implementation, the general administrative setting, as well as the interpretation of WFD categories related to economic evaluations will be illustrated. Two major issues of particularly high relevance in the present debate are then discussed: a) the evaluation of environmental and resource costs; and b) water regulation in agriculture.Department of Agricultural Economics and Engineering, University of Bologna (Italy). Department of Statistics, University of Bologna (Italy)