Kalman Filter Track Fits and Track Breakpoint Analysis

We give an overview of track fitting using the Kalman filter method in the NOMAD detector at CERN, and emphasize how the wealth of by-product information can be used to analyze track breakpoints (discontinuities in track parameters caused by scattering, decay, etc.). After reviewing how this information has been previously exploited by others, we describe extensions which add power to breakpoint detection and characterization. We show how complete fits to the entire track, with breakpoint parameters added, can be easily obtained from the information from unbroken fits. Tests inspired by the Fisher F-test can then be used to judge breakpoints. Signed quantities (such as change in momentum at the breakpoint) can supplement unsigned quantities such as the various chisquares. We illustrate the method with electrons from real data, and with Monte Carlo simulations of pion decays.Comment: 27 pages including 10 figures. To appear in NI

A complete simulation of a triple-GEM detector

Since some years the gas electron multipliers (GEM)based detectors have been proposed for many different applications, in particular, in high-energy physics and astrophysics experiments and medical imaging. Many experimental measurements and tests have been performed to investigate their characteristics and performances. To achieve a better understanding of the behavior of this kind of detector the computer simulation is a very important tool. In this paper, a complete and detailed simulation of a triple-GEM-based detector is described. A method has been developed to take into account all the processes from the ionization mechanism up to the signal formation and electronic response. The results obtained are compared with experimental data and a very good agreement is achieved

Aging measurements on triple-GEM detectors operated with CF4-based gas mixtures

We present the results of a global irradiation test of full size triple-GEM detectors operated with CF 4 -based gas mixtures. This study has been performed in the framework of an R&D activity on detectors for the innermost region of the first muon station of the LHCb experiment. The prototypes have been irradiated at the Calliope facility of the ENEA-Casaccia with a high intensity 1.25 MeV γ 60 Co source. After the irradiation test the detectors performances have been measured with X-rays and with a 3 GeV pion beam at CERN. A SEM analysis on several samples of the detectors has been performed to complete the understanding of the physical processes occurring in a GEM detector during a strong irradiation

Production and performance of LHCb triple-GEM detectors equipped with the dedicated CARDIAC-GEM front-end electronics

The production of the triple-GEM detectors for the innermost region of the first muon station of the LHCb experiment has started in February 2006, and is foreseen to be completed by the end of July. The final design of the detector and the construction procedure and tools, as well as the quality controls are defined. The performances of each detector, composed by two triple-GEM chambers equipped with dedicated CARDIAC-GEM front-end electronics, are studied with a cosmic ray telescope. The cosmic ray telescope has been set up including all the final off-detector components

Impact of depression on circulating endothelial progenitor cells in patients with acute coronary syndromes

Aims: Depression has been identified as a risk factor for an adverse prognosis and reduced survival in patients with acute coronary syndrome (ACS). The number of endothelial progenitor cells (EPCs) is an independent predictor of clinical outcomes in patients with ACS. The aim was to evaluate the impact of depression on EPC levels in patients with ACS. Methods: Out of 74 ACS patients [23 non-ST-segment elevation myocardial infarction (NSTEMI), 48 STEMI], 36 had a diagnosis of major depressive episode (MDE) according to Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) criteria at the time of the inclusion in the study. Control groups were as follows: 15 healthy individuals and 18 patients with current MDE without a history of cardiovascular diseases. EPCs were defined as CD34RCD133RKDRR and evaluated by flow cytometry. All patients underwent standardized cardiological and psychopathological evaluations. Parametric and nonparametric statistical tests were performed wherever appropriate. Results: ACS patients with MDE showed a significant decrease in circulating EPC number compared with ACS patients without MDE (P <0.001). The ACS study population was then subdivided into STEMI and NSTEMI groups, and inside each group again patients with MDE showed a significant decrease in circulating CD34RCD133RKDRR EPCs compared with others (P <0.001). Conclusion: We showed that ACS patients with MDE have a reduced number of circulating CD34RCD133RKDRR cells compared with ACS patients without MDE, suggesting that the presence of MDE reduces the response of bone marrow to acute ischemic events. Considering the reparative role of EPCs in ACS patients, we suppose that patients with MDE might be protected less than patients without MDE

Fabrication and Characterisation of 3D Diamond Pixel Detectors With Timing Capabilities

Diamond sensors provide a promising radiation hard solution to the challenges posed by the future experiments at hadron machines. A 3D geometry with thin columnar resistive electrodes orthogonal to the diamond surface, obtained by laser nanofabrication, is expected to provide significantly better time resolution with respect to the extensively studied planar diamond sensors. We report on the development, production, and characterisation of innovative 3D diamond sensors achieving 30% improvement in both space and time resolution with respect to sensors from the previous generation. This is the first complete characterisation of the time resolution of 3D diamond sensors and combines results from tests with laser, beta rays and high energy particle beams. Plans and strategies for further improvement in the fabrication technology and readout systems are also discussed

Intrinsic time resolution of 3D-trench silicon pixels for charged particle detection

In the last years, high-resolution time tagging has emerged as the tool to tackle the problem of high-track density in the detectors of the next generation of experiments at particle colliders. Time resolutions below 50ps and event average repetition rates of tens of MHz on sensor pixels having a pitch of 50$\mu$m are typical minimum requirements. This poses an important scientific and technological challenge on the development of particle sensors and processing electronics. The TIMESPOT initiative (which stands for TIME and SPace real-time Operating Tracker) aims at the development of a full prototype detection system suitable for the particle trackers of the next-to-come particle physics experiments. This paper describes the results obtained on the first batch of TIMESPOT silicon sensors, based on a novel 3D MEMS (micro electro-mechanical systems) design. Following this approach, the performance of other ongoing silicon sensor developments has been matched and overcome, while using a technology which is known to be robust against radiation degradation. A time resolution of the order of 20ps has been measured at room temperature suggesting also possible improvements after further optimisations of the front-end electronics processing stage.Comment: This version was accepted to be published on JINST on 21/07/202

Correlated 0.01Hz-40Hz seismic and Newtonian noise and its impact on future gravitational-wave detectors

We report correlations in underground seismic measurements with horizontal separations of several hundreds of meters to a few kilometers in the frequency range 0.01Hz to 40Hz. These seismic correlations could threaten science goals of planned interferometric gravitational-wave detectors such as the Einstein Telescope as well as atom interferometers such as MIGA and ELGAR. We use seismic measurements from four different sites, i.e. the former Homestake mine (USA) as well as two candidate sites for the Einstein Telescope, Sos Enattos (IT) and Euregio Maas-Rhein (NL-BE-DE) and the site housing the MIGA detector, LSBB (FR). At all sites, we observe significant coherence for at least 50% of the time in the majority of the frequency region of interest. Based on the observed correlations in the seismic fields, we predict levels of correlated Newtonian noise from body waves. We project the effect of correlated Newtonian noise from body waves on the capabilities of the triangular design of the Einstein Telescope's to observe an isotropic gravitational-wave background (GWB) and find that, even in case of the most quiet site, its sensitivity will be affected up to $\sim$20Hz. The resolvable amplitude of a GWB signal with a negatively sloped power-law behaviour would be reduced by several orders of magnitude. However, the resolvability of a power-law signal with a slope of e.g. $\alpha=0$ ($\alpha=2/3$) would be more moderately affected by a factor $\sim$ 6-9 ($\sim$3-4) in case of a low noise environment. Furthermore, we bolster confidence in our results by showing that transient noise features have a limited impact on the presented results

Observation of J/ψpJ/\psi p resonances consistent with pentaquark states in Λb0→J/ψK−p{\Lambda_b^0\to J/\psi K^-p} decays

Observations of exotic structures in the $J/\psi p$ channel, that we refer to as pentaquark-charmonium states, in $\Lambda_b^0\to J/\psi K^- p$ decays are presented. The data sample corresponds to an integrated luminosity of 3/fb acquired with the LHCb detector from 7 and 8 TeV pp collisions. An amplitude analysis is performed on the three-body final-state that reproduces the two-body mass and angular distributions. To obtain a satisfactory fit of the structures seen in the $J/\psi p$ mass spectrum, it is necessary to include two Breit-Wigner amplitudes that each describe a resonant state. The significance of each of these resonances is more than 9 standard deviations. One has a mass of $4380\pm 8\pm 29$ MeV and a width of $205\pm 18\pm 86$ MeV, while the second is narrower, with a mass of $4449.8\pm 1.7\pm 2.5$ MeV and a width of $39\pm 5\pm 19$ MeV. The preferred $J^P$ assignments are of opposite parity, with one state having spin 3/2 and the other 5/2.Comment: 48 pages, 18 figures including the supplementary material, v2 after referee's comments, now 19 figure

Array analysis of seismic noise at the Sos Enattos mine, the Italian candidate site for the Einstein Telescope

The area surrounding the dismissed mine of Sos Enattos (Sardinia, Italy) is the Italian candidate site for hosting Einstein Telescope (ET), the third-generation gravitational wave (GW) observatory. One of the goals of ET is to extend the sensitivity down to frequencies well below those currently achieved by GW detectors, i.e. down to 2 Hz. In the bandwidth [1,10] Hz, the seismic noise of anthropogenic origin is expected to represent the major perturbation to the operation of the infrastructure, and the site that will host the future detector must fulfill stringent requirements on seismic disturbances. In this paper we describe the operation of a temporary, 15-element, seismic array deployed in close proximity to the mine. Signals of anthropogenic origin have a transient nature, and their spectra are characterized by a wide spectral lobe spanning the [3,20] Hz frequency interval. Superimposed to this wide lobe are narrow spectral peaks within the [3,8] Hz frequency range. Results from slowness analyses suggest that the origin of these peaks is related to vehicle traffic along the main road running east of the mine. Exploiting the correlation properties of seismic noise, we derive a dispersion curve for Rayleigh waves, which is then inverted for a shallow velocity structure down to depths of ≈≈ 150 m. This data, which is consistent with that derived from analysis of a quarry blast, provide a first assessment of the elastic properties of the rock materials at the site candidate to hosting ET