In order to reconstruct γγ physics events tagged with High Energy Tagger (HET) in the KLOE-2 (K LOng Experiment 2), we need to measure the Time Of Flight (TOF) of the electrons and positrons from the ...KLOE-2 Interaction Point (IP) to our tagging stations (11m apart). The required resolution must be better than the bunch spacing (2.7ns). We have developed and implemented on a Xilinx Virtex-5 FPGA a Time to Digital Converter (TDC) with 625ps resolution (LSB) along with an embedded data acquisition system and the interface to the online FARM of KLOE-2. We will describe briefly the architecture of the TDC and of the Data AcQuisition (DAQ) system. Some more details will be provided about the zero-suppression algorithm used to reduce the data throughput.
The upgrade of the KLOE detector at DAFNE, the Φ-factory at the Laboratori Nazionali di Frascati, foresees the insertion of an Inner Tracker around the interaction region, composed of four layers ...with diameters from 26cm to 41cm and an active length of 70cm. Each layer is realized as a cylindrical triple-GEM detector, a solution that allows to keep the total material of the Inner Tracker below 2% of a radiation length, which is of utmost importance to limit the multiple scattering of low-momentum tracks and to minimize dead spaces, thus maximizing the detector's active area. The peculiar read-out pattern with X and V strips provides a spatial resolution of about 200μm and 400μm for azimuthal and longitudinal coordinates, respectively.
After 2 years, the construction of the Inner Tracker has been completed and the detector is ready to be inserted in the KLOE apparatus for a next data-taking run. The details of the manufacturing procedure as well as the results of validation tests are reported.
The KLOE-2 experiment started its data taking campaign in November 2014 with an upgraded tracking system at the DAΦNE electron-positron collider at the Frascati National Laboratory of INFN. The new ...tracking device, the Inner Tracker, operated together with the KLOE-2 Drift Chamber, has been installed to improve track and vertex reconstruction capabilities of the experimental apparatus. The Inner Tracker is a cylindrical GEM detector composed of four cylindrical triple-GEM detectors, each provided with an X-V strips-pads stereo readout. Although GEM detectors are already used in high energy physics experiments, this device is considered a frontier detector due to its fully-cylindrical geometry: KLOE-2 is the first experiment benefiting of this novel detector technology. Alignment and calibration of this detector will be presented together with its operating performance and reconstruction capabilities.
A general purpose FPGA based DAQ module has been developed. This module has been built around a Virtex-4 FPGA and it is able to acquire up to 1024 different channels distributed over 10 slave cards. ...The module has an optical interface, a RS-232 port, a USB and a Gigabit Interface. The KLOE-2 experiment is going to use this module to acquire data from the Inner tracker. An embedded processor (Power PC) is present on the FPGA and a telnet server has been developed and installed. A new general purpose data taking system has been based on this new module to acquire the Inner Tracker. The system is presently working at LNF (Laboratori Nazionali di Frascati).
Part of the upgrade of the KLOE detector at the DAPhiNE Phi-factory consists of the insertion of a tracking device around the interaction region, composed of four tracking layers with radii from 130 ...mm to 205 mm and an active length of 700 mm. Each layer was realized as a cylindrical triple-GEM (CGEM) kapton-based detector, a solution that allows us to keep the total material budget below 2% of chi sub(0), of utmost importance to limit the multiple scattering of low-momentum tracks at KLOE-2, and to minimize dead spaces. The peculiar readout pattern with XV strips provides a spatial resolution of about 200 mu m on both views, while a dedicated readout system has been developed by the KLOE-2 collaboration. It is composed of a digital readout front-end card based on the GASTONE ASIC and a General Interface Board with a configurable FPGA architecture and Gigabit Ethernet. The construction of the four CGEM layers has been completed and the detectors have been tested with a beta source and cosmic-ray muons. The insertion inside the KLOE apparatus was performed in July 2013. The construction procedure and the results of the validation tests will be reported.
A new front-end data acquisition (DAQ) system has been conceived for the data collection of the new detectors which will be installed by the KLOE2 collaboration. This system consists of a general ...purpose FPGA based DAQ module and a VME board hosting up to 16 optical links. The DAQ module has been built around a Virtex-4 FPGA and it is able to acquire up to 1024 different channels distributed over 16 front-end slave cards. Each module is a general interface board (GIB) which performs also first level data concentration tasks. The GIB has an optical interface, a RS-232, an USB and a Gigabit Ethernet Interface. The optical interface will be used for DAQ purposes while the Gigabit Ethernet interface for monitoring tasks and debug. Two new detectors exploit this strategy to collect data. Optical links are used to deliver data to the VME board which performs data concentration tasks. The return optical link from the board to the GIB is used to initialize the front-end cards. The VME interface of the module implements the VME 2eSST protocol in order to sustain a peak data rate of up to 320MB/s. At the moment the system is working at the Frascati National Laboratory (LNF).
The existence of a new force beyond the Standard Model is compelling because it could explain several striking astrophysical observations which fail standard interpretations. We searched for the ...light vector mediator of this dark force, the U boson, with the KLOE detector at the DAΦNE e+e− collider. Using an integrated luminosity of 1.54 fb−1, we studied the process e+e−→Uγ, with U→e+e−, using radiative return to search for a resonant peak in the dielectron invariant-mass distribution. We did not find evidence for a signal, and set a 90% CL upper limit on the mixing strength between the Standard Model photon and the dark photon, ε2, at 10−6–10−4 in the 5–520 MeV/c2 mass range.
The three precision measurements of the cross section σ(e+e− → π+π−γ(γ)) using initial state radiation by the KLOE collaboration provide an important input for the prediction of the hadronic ...contribution to the anomalous magnetic moment of the muon. These measurements are correlated for both statistical and systematic uncertainties and, therefore, the simultaneous use of these measurements requires covariance matrices that fully describe the correlations. We present the construction of these covariance matrices and use them to determine a combined KLOE measurement for σ(e+e− → π+π−γ(γ)). We find, from this combination, a two-pion contribution to the muon magnetic anomaly in the energy range 0.10 < s < 0.95 GeV2 of aμπ+π−=489.8±1.7stat±4.8sys×10−10.Data vectors and covariance matrices are available at http://www.lnf.infn.it/kloe/ppg/ppg_2017/ppg_2017.html.
We searched for the μ+μ− decay of a light vector gauge boson, also known as dark photon, in the e+e−→μ+μ−γISR process by means of the Initial State Radiation (ISR) method. We used 1.93 fb−1 of data ...collected by the KLOE experiment at the DAΦNE ϕ-factory. No structures have been observed over the irreducible μ+μ− background. A 90% CL limit on the ratio ε2=α′/α between the dark coupling constant and the fine structure constant of 3×10−6–2×10−7 has been set in the dark photon mass region between 519 MeV and 973 MeV. This new limit has been combined with the published result obtained investigating the hypothesis of the dark photon decaying into hadrons in e+e−→π+π−γISR events. The combined 90% CL limit increases the sensitivity especially in the ρ–ω interference region and excludes ε2 greater than (13−2)×10−7. For dark photon masses greater than 600 MeV the combined limit is lower than 8 ×10−7 resulting more stringent than present constraints from other experiments.
The use of atypical antipsychotic drugs in the elderly has become wider and wider in recent years; in fact, these agents have novel receptor binding profiles, good efficacy with regard to negative ...symptoms, and reduced extrapyramidal symptoms. However, in recent years, the use of both conventional and atypical antipsychotics has been widely debated for concerns about their safety in elderly patients affected with dementia and the possible risks for stroke and sudden death. A MEDLINE search was made using the words elderly, atypical antipsychotics, use, schizophrenia, psychosis, mood disorders, dementia, behavioral disorders, and adverse events. Some personal studies were also considered. This paper reports the receptor binding profiles and the main mechanism of action of these drugs, together with their main use in psychiatry and the possible adverse events in elderly people.
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