F. Simonetto

We report on a study of inclusive particle production in pp-interactions at 400 GeV/c. The data are based on 472 K reconstructed events recorded in the NA 27 experiment using the LEBC-EHS facility at CERN. The production cross sections are determined of pseudo scalar (π±,0, η andK ±), scalar (f 0(975)), vector (ρ±,0(770), ω(783), ϕ(1020),K *0(892), and $$\bar K^{ * 0} $$ (892)), and tensorf 0 mesons, of protons and antiprotons, and theΔ ++,+,0(1232), and Λ(1520) baryon resonances in the forward hemisphere of the center of mass system, as well as longitudinal and transverse momentum distributions. The results are compared with predictions of the FRITIOF model and with other experimental data.

Results are presented from a test in the CERN SPS North Area of a prototype of the DELPHI microvertex detector. Full-sized modules built up from prototype ac-coupled detectors and VLSI readout electronics were used. The spatial resolution of the detectors equipped with prototype VLSI chips was measured to be 6.5 μm. The system aspects, including the readout, were found to work well. Extrapolating to the final components we expect to achieve a measurement precision of 5 μm with the DELPHI microvertex detector.

The inclusive production of vector mesons (charged ρ(770), ω(783), ϕ(1020) and neutralK *(892)) in π− p interactions at 360 GeV/c is studied. The data are based on 160 000 reconstructed events recorded in the NA 27 Experiment using the LEBC-EHS facility at CERN. The production cross sections in the forward hemisphere in c.m.s. and the longitudinal momentum distributions are determined. The results are compared with data obtained at lower energies.

Bose-Einstein correlations among identically charged pions produced inpp collisions at 400 GeV/c are studied using the EHS spectrometer. Empoying the Kopylov-Podgoretskii parametrization, the average size of the emitting regionr k and its lifetime τ for pion production were determined to ber k=1.71±0.04 fm andcτ=0.89±0.05fm. The average sizer g in terms of the Lorentz invariant Goldhaber parametrization was determined to ber g=1.20±0.03fm. A decrease of the size with increasing momentum of the pions was observed. The size and the incoherence parameter of the pion emitting region were determined as a function of the charged particle multiplicity and the momentum of the pions. Identified charged kaons were used to study Bose-Einstein correlations among identically charged kaonsK ±K±. The average size of the emitting region for kaon production was determined to ber k=1.87±0.33fm in terms of the Kopylov-Podgoretskii parametrization. A study of the influence of a reference sample is presented.

Abstract The design and progress in the construction of the DELPHI microvertex detector are presented. The layout is described, together with results on precision mounting of silicon detectors. The development of ac-coupled silicon microstrip detectors was an important contribution to the design. The use of low-power CMOS readout chips facilitates the cooling of the detector. A description of the fourth-generation readout processor for silicon strip detectors, the SIROCCO IV, implemented in FASTBUS, is given. Finally, two complementary systems for in-situ position monitoring of the detectors are described.

As a part of a large experimental program aiming to produce high quality calibration data for the Forward ElectroMagnetic Calorimeter (FEMC) of the DELPHI detector at LEP, special runs were devoted to the study of the transverse profile of electromagnetic showers in lead glass. Results of this study are presented.

The contribution of the microstrip silicon vertex detector to the physics from the DELPHI experiment at LEP is presented. The tagging of quark flavour for Z0 decays to (dd, uu, ss), cc, bb, tt, and the spectroscopy of short-lived particles are the most natural initial physics goals for a vertex detector and provide a good introduction to more exotic physics investigations. Results of the Monte Carlo studies show the considerable improvement given by the vertex detector to these fields. The features important for the physics performance, such as detector geometry, measurement precision, alignment and pattern recognition, are discussed. Finally, some preliminary remarks concerning simple but efficient improvements of the detector geometry for the future are made.

This article presents a method to simulate the response of a particle detector using a fast technique. Considering the symmetry in the detectors in ring accelerators, the usual tracking procedures are simplified, modifying both the description of the devices, and the tracking itself. This method is applied to the DELPHI experiment.

A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower very fine samplings e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and electron/pion separation are reported.

Two techniques for longitudinal segmentation of shashlik calorimeters are proposed. Results concerning energy resolution and e/π separation are reported.

Two mathematical methods, the Fourier and wavelet transforms, were used to study the short term cardiovascular control system. Time series, picked from electrocardiogram and arterial blood pressure lasting 6 minutes, were analyzed in supine position (SUP), during the first (HD1) and the second parts (HD2) of 90° head down tilt, and during recovery (REC). The wavelet transform was performed using the Haar function of period [Formula: see text] to obtain wavelet coefficients. Power spectra components were analyzed within three bands, VLF (0.003–0.04), LF (0.04–0.15) and HF (0.15–0.4) with the frequency unit cycle/interval. Wavelet transform demonstrated a higher discrimination among all analyzed periods than the Fourier transform. For the Fourier analysis, the LF of R–R intervals and VLF of systolic blood pressure show more evident difference for different body positions. For the wavelet analysis, the systolic blood pressures show much more evident differences than the R–R intervals. This study suggests a difference in the response of the vessels and the heart to different body positions. The partial dissociation between VLF and LF results is a physiologically relevant finding of this work.

During the second long shut-down of the LHC, the first endcap station of the CMS muon system will be upgraded using Triple Gas Electron Multiplier (GEM) detectors. In order to gain first operational experience, a limited number of chambers has been installed in January 2017 as a "slice test" of the upgrade. During the slice test, irreversible channel loss in the test version of the front-end electronics has been observed. In order to understand the origin of such channel loss, and to verify whether this problem arises also for the final frontend electronics, a measurement campaign has been launched in June 2018. The experimental conditions faced at CMS have been reproduced in the laboratory in order to investigate different causes of the channel loss: detector mis-configuration, high- energy deposits of minimum ionizing particles, highly ionizing particles and photon background. The channel loss has been correlated with propagating discharges to the anode plane. In this contribution we show a procedure to detect channel losses in the front-end readout electronics, the experimental setup used to investigate the different hypothesis and some preliminary results.

We study the optical properties of glass exposed to ionizing radiation, as it occurs in the space environment. 24 glass types have been considered, both space qualified and not space qualified. 72 samples (3 for each glass type) have been irradiated to simulate a total dose of 10krad and 30krad, imposed by a proton beam at KVI-Centre of Advanced Radiation Technology (Groeningen). Combining the information about stopping power and proton fluence, the time required to reproduce any given total dose in the real environment can be easily obtained. The optical properties, such as spectral transmission and light scattering have been measured before and after irradiation for each sample. Transmission has been characterized within the wavelength range 200 nm-1100 nm. Indications that systematical issues depend on the dopant or composition are found and described. This work aims at extending the existing list of space-compliant glasses in terms of radiation damage.

The hypothesis of a real Cabibbo-Kobayashi-Maskawa matrix has been considered and found to be disfavoured by present measurements even when neglecting results from CP violation in neutral kaon decay. The Best Linear Unbiased Estimator has been used as a statistical approach to compute the confidence level. This result agrees with most of the previous literature but contradicts statements reported in a recent paper.

The CMS experiment has measured the production of heavy flavored hadrons and jets at 7 TeV. A large range of inclusive and exclusive cross-section measurements (Quarkonia, charged and neutral B hadrons) as well as studies of b angular correlations were made and compared to theoretical predictions at Leading Order and Next to Leading Order precision. These results are here reviewed.

In this paper, recent results in the B-physics field achieved using proton–proton collision data at [Formula: see text] and [Formula: see text] TeV collected by CMS are presented. They include the angular analysis of the decay [Formula: see text] with Run 1 data, new measurements of D and B meson production cross-sections and CP violation studies using [Formula: see text] decays with Run 2 data. The results are compared with the Standard Model predictions. A measurement of the CP-violating phase [Formula: see text] achieved by combining results from both Run 1 and Run 2 data is also presented.

Art&Science across Italy is an INFN/CERN project for the Italian High School students (16-18 y.o.).More than 10.000 students joined since the 2016.Creativity and vision capability are common to many disciplines and are involved in artistic and scientific thinking and activities.Scientists and artists are often asked to see and think beyond the perceivable reality, to imagine aspects of things and events, which can be better seen from an unusual perspective.The main idea is to put in practice the basic concept of the STEAM field in which neither STEM nor arts are privileged over the other, but both are equally in play.Therefore, our aim is to engage high school students with science using artistic languages, regardless of students' specific skills or level of knowledge

The hypothesis of a real Cabibbo-Kobayashi-Maskawa matrix has been considered and found to be disfavoured by present measurements even when neglecting results from CP violation in neutral Kaon decay. The Best Linear Unbiased Estimator has been used as a statistical approach to compute the Confidence Level. A new way to take into account the information from Bs mesons oscillations has been considered, reducing considerably the error on extractions of rho and eta parameter of the Wolfenstain parametrization of the matrix.

We have constructed a prototype of an electromagnetic calorimeter, for future linear collider experiments, alternating 45 layers of lead and scintillator planes. The scintillation light is collected by means of WLS fibers from square cells of 5/spl times/5 cm/sup 2/. To improve the reconstruction of the shower profile, three silicon pad (/spl sim/0.9/spl times/0.9 cm/sup 2/) detector planes have been inserted between the lead and scintillator layers at 2.6 and 12 X/sub 0/. The prototype has been tested with electron beams at low (50/spl divide/750 MeV) and high energies (5/spl divide/50 GeV): a good linearity in response and an energy resolution of /spl sim/11.5%//spl radic/(E/GeV) have been achieved. A position resolution of 2.5 mm has also been measured for 10 GeV impinging electrons. The calorimeter particle identification capability has been tested comparing electron and pion beams.

We study the optical properties of glass exposed to ionizing radiation as it occurs in the space environment. Twenty-four glass types have been considered, both space-qualified and not space-qualified. Seventy-two samples (3 for each glass type) have been irradiated to simulate total doses of 10 and 30 krad imposed by a proton beam at KVI-Centre of Advanced Radiation Technology (Groeningen). Combining information concerning stopping power and proton fluence, the time required to reproduce any given total dose in a real environment can be easily obtained. The optical properties, such as spectral transmission and light scattering, have been measured before and after irradiation for each sample. Transmission has been characterized within the wavelength range of 200 to 1100 nm. Indications that systematical issues depend on the dopant or composition are found and described. Our work aims at extending the existing list of space-compliant glasses in terms of radiation damage.

A prototype of an electromagnetic sampling calorimeter for future linear collider experiments has been commissioned by the LCCAL collaboration. In order to improve the reconstruction of the shower profile, three silicon pad detector planes have been inserted between lead and scintillator layers at 2, 6 and 12 X/sub 0/. The scintillator light is collected by means of lateral W.L.S. fibers. The electrical parameters of the pad detectors have been determined by a static IV and CV characterisation; charge collection efficiency and tracking capability have been measured during beam tests. Results from test-beam runs are shown.

Two techniques for longitudinal segmentation of shashlik calorimeters are proposed. Results concerning energy resolution, impact point reconstruction and e//spl pi/ separation are reported.

Two techniques for longitudinal segmentation of shashlik calorimeters are proposed. Results concerning energy resolution, impact point reconstruction and e/n separation are reported.

Combined results on b-hadron lifetimes, b-hadron production rates, B{sub d}{sup 0}-{bar B}{sub d}{sup 0} and B{sub s}{sup 0}-{bar B}{sub s}{sup 0} oscillations, the decay width difference between the mass eigenstates of the B{sub s}{sup 0}-{bar B}{sub s}{sup 0} system, the average number of c and {bar c} quarks in b-hadron decays, and searches for CP violation in the B{sub d}{sup 0}-{bar B}{sub d}{sup 0} system are presented. They have been obtained from published and preliminary measurements available in Summer 2000 from the ALEPH, CDF, DELPHI, L3, OPAL and SLD Collaborations. These results have been used to determine the parameters of the CKM unitarity triangle.

A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Performance in terms of energy resolution, impact point reconstruction and eπ separation are reported.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Simonetto Franco, The DELPHI Collaboration; A measurement of BB̄ mixing with the DELPHI detector at LEP. AIP Conf. Proc. 1 February 1992; 272 (1): 468–471. https://doi.org/10.1063/1.43552 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search