High-speed electronics of the T0 detector for the ALICE experiment (CERN)

The design and special features of the main units of high-speed electronics for the trigger subsystem of the T0 detector of the ALICE experiment are considered. Its characteristic time resolution is 50 ps. The dead time does not exceed 25 ns.     

Simulations of the PHOS detector in the ALICE experiment at CERN

In 2005 the ALICE experiment will start at the Large Hadron Collider at CERN. It will investigate hot and dense strongly interacting matter formed in heavy ion collisions. The photon spectrometer of the ALICE detector will be designed to identify direct photons. To optimize the detector, simulations will be carried out.     

Physics with the ALICE experiment

ALICE experiment at LHC collects data in pp collisions at 1497-1 = 0.9, 2.76, and 7 TeV and in PbPb collisions at 2.76 TeV. Highlights of the detector performance and an overview of experimental results measured with ALICE in pp and AA collisions are presented in this paper. Physics with protonproton collisions is focused on hadron spectroscopy at low and moderate p _t . Measurements with lead-lead collisions are shown in comparison with those in pp collisions, and the properties of hot quark matter are discussed.     

The Time Of Flight (TOF) system of the ALICE experiment

The European Physical Journal C - The double-stack Multigap Resistive Plate Chamber (MRPC) is the detector chosen for the large Time-Of-Flight system of the ALICE experiment at CERN LHC. The TOF...     

Heavy ions with the Large Hadron Collider and the ALICE detector

The Large Hadron Collider (LHC) under construction at CERN is also planned as a heavy ion collider with lead ions colliding at an energy of 2.7+2.7 ATeV. This corresponds to collisions of matter with cosmic rays of the utmost energies observed so far promising the study of new and exciting aspects of physics. Minor improvements of the newly commissioned lead ion source at the CERN SPS are necessary in order to provide a luminosity of L=2×10²⁷ cm^?2s^?1. The detector ALICE has been chosen as the third detector for the LHC and will be dedicated to the physics of these nuclear collisions and also to the large cross section physics in p+p collisions.     

Heavy flavour capabilities of the ALICE transition radiation detector

The ALICE Transition Radiation Detector (TRD) enhances the detection sensitivity of heavy-flavour production of the ALICE experiment at the LHC by providing electron identification above and fast trigger capabilities above . The combined particle identification from the Inner Tracking System (ITS), the Time Projection Chamber (TPC) and the Transition Radiation Detector enables measurements of D-mesons and B-mesons and, potentially, the Λ_b, assuming the reconstruction of the .     

Investigations of the new generation pixel detectors for ALICE experiment at LHC

We present the results from testing Monolithic Active Pixel Sensors of the detector ALPIDE (ALICE Pixel Detector). The purpose of these tests was to measure the pixel threshold and noise distributions in each of the four sectors of the detector, as well as the analysis of the hit maps produced by different radioactive sources.     

Physics perspectives of the ALICE experiment at the large hadron collider

The large hadron collider (LHC) under construction at CERN will deliver ion beams up to centre of mass energies of the order of 5.5 TeV per nucleon, in case of lead. If compared to the available facilities for the study of nucleus-nucleus collisions (SpS and RHIC), this represents a huge step forward in terms of both volume and energy density that can be attained in nuclear interactions. ALICE (a large ion collider experiment) is the only detector specifically designed for the physics of nuclear collisions at LHC, even though it can also study high cross-section processes occurring in proton-proton collisions. The main goal of the experiment is to observe and study the phase transition from hadronic matter to deconfined partonic matter (quark gluon plasma —QGP). ALICE is conceived as a general-purpose detector and will address most of the phenomena related to the QGP formation at LHC energies: for this purpose, a large fraction of the hadrons, leptons and photons produced in each interaction will be measured and identified.     

Primary vertex in the ALICE experiment in absence of the event reconstruction

ALICE is a general-purpose apparatus for the study of ultra-relativistic heavy-ion collisions at the Large Hadron Collider of the CERN. The study of such reactions demands the determination of the primary vertex in three dimensions with good resolution. We have developed an algorithm for finding the vertex position even in absence of the event reconstruction. The performances of such an algorithm have been studied as a function of the vertex position, particle multiplicity and magnetic field.     

Simulation study on light vector meson decays to electron-positron pairs with the ALICE experiment

Simulation study on ω, ϕ, ρ decays to e ⁻ e ⁺ pairs in the ALICE detector for Pb-Pb collisions at LHC energy was performed. The possibility of selecting resonance signals over the combinatorial backgrounds is demonstrated using the realistic simulation tracking and particle identification algorithms of the ALICE offline framework (AliRoot). Results for J/ψ are presented also for comparison.     

The digital trigger system for the RED-100 detector

The system for forming a trigger for the liquid xenon detector RED-100 is developed. The trigger can be generated for all types of events that the detector needs for calibration and data acquisition, including the events with a single electron of ionization. In the system, a mechanism of event detection is implemented according to which the timestamp and event type are assigned to each event. The trigger system is required in the systems searching for rare events to select and keep only the necessary information from the ADC array. The specifications and implementation of the trigger unit which provides a high efficiency of response even to low-energy events are considered.     

New CHOD detector for the NA62 experiment at CERN

The New CHOD is a scintillation hodoscope with a pad structure featuring a total of 148 counters. The signal from each pad is read out using wavelength-shifting fibers and two or four SensL SiPMs with a sensitive area of 3 × 3 mm². This photodetector has 4774 pixels 35 × 35 μm² in size. The key parameters (photon detection efficiency, dark current, crosstalk, and gain) were measured for 500 SiPMs.     

A hadron blind detector for the PHENIX experiment at RHIC

A hadron blind detector (HBD) is to be installed in the PHENIX experiment for Run7, starting in fall 2006. The HBD is a threshold Čerenkov detector designed to measure electrons in a field free region surrounding the collision vertex. The HBD’s primary purpose is to tag background electrons originating from photon conversion and Dalitz decays. These background electrons can subsequently be excluded from a dilepton analysis, thereby reducing the combinatorial background by up to a factor of 100. The detector is realized by a proximity-focus windowless Čerenkov detector operating with pure CF₄ and read out by a reflective photocathode consisting of a stack of gas electron multipliers (GEM), the first of which is coated with 300 nm of CsI. The avalanche charge from the GEM stack is collected on a PCB with pads having similar size to the Čerenkov blob. Dalitz and photon conversions are tagged by having twice the amplitude of a single blob. An excellent Quantum Efficiency of the photocathode is thus crucial to the success of the device. Outstanding results have been accomplished using a vacuum evaporation facility on loan from INFN Rome. We will give an overview of the experimental methods to identify blobs and techniques developed for photocathode production.     

Measurement of the W boson mass with the D0 detector

We present a measurement of the W boson mass using data corresponding to 4.3 fb(-1) of integrated luminosity collected with the D0 detector during Run II at the Fermilab Tevatron pp collider. With a sample of 1,677,394 W → eν candidate events, we measure M(W) = 80.367 ± 0.026 GeV. This result is combined with an earlier D0 result determined using an independent Run II data sample, corresponding to 1 fb(-1) of integrated luminosity, to yield M(W) = 80.375 ± 0.023 GeV.     

Search for magnetic monopoles with the nuclear track detector of the MACRO experiment at gran SASSO

In this paper the limits are presented which were obtained by the search for magnetic monopoles using the MACRO track-etch subdetector as a stand alone detector. We compare the flux upper limit for g = g_D monopoles to other limits obtained by different subdetectors of MACRO, till August 1, 1995, when the construction of the apparatus was completed. The global MACRO monopole limit is compared with other limits from different experiments.     

Prospects for the measurement of B 0 s oscillations with the ATLAS detector at LHC

The feasibility for mass measurements of supersymmetric particles from minimal gauge mediated models in the ATLAS detector at the large hadron collider is studied using parameterized simulations. The covered models are characterized by having the supersymmetric tau as the only next-to-lightest supersymmetric particle (NLSP). Given independent measurements of the lightest Higgs mass and the NLSP lifetime, a sufficient number of supersymmetric particle mass measurements are performed such that all underlying model parameters are constrained.     

Double-beta decay with the NEMO experiment: Status of the NEMO 3 detector

The NEMO 3 detector, devoted to search for the neutrinoless double-beta decay, will be able to reach the sensitivity to 〈m _ν〉 of the order of 0.1 eV. The expected performance of the detector for signal detection and both internal and external background rejection is presented. A specific study of the neutron-induced background is given. The NEMO Collaboration is now mounting the detector in the Fréjus underground laboratory.     

Observation of KS0 semileptonic decays with the CMD-2 detector

The decay K_S⁰→πeν has been observed by the CMD-2 detector at the e⁺e⁻ collider VEPP-2M at Novosibirsk. Of 6 million produced K_L⁰K_S⁰ pairs, 75±13 events of the K_S⁰→πeν decay were selected. The corresponding branching ratio is B(K_S⁰→πeν)=(7.2±1.4)×10⁻⁴. This result is consistent with the evaluation of B(K_S⁰→πeν) from the K_L⁰ semileptonic rate and K_S⁰ lifetime assuming ΔS=ΔQ .