D. De Gruttola

Results of the ALICE time-of-flight detector from the 2009 cosmic-ray data taking

The Time-Of-Flight detector (TOF) of the ALICE experiment at the CERN LHC is based on Multi-gap Resistive Plate Chambers (MRPCs). The TOF detector consists of 152928 readout channels covering a total area of 141 m2. In this paper the results of the calibration with cosmic-ray data collected during 2009 are presented.

A multigap resistive plate chamber array for the Extreme Energy Events project

The Extreme Energy Events (EEE) Project is a Centro Fermi - CERN - INFN - MIUR Collaboration Project for the study of extremely high energy cosmic rays, which exploits the Multigap Resistive Plate Chamber (MRPC) technology. The excellent time resolution and good tracking capability of this kind of detector allows us to study Extensive Air Showers (EAS) with an array of MRPC telescopes distributed across the Italian territory. Each telescope is installed in a high school, with the further goal to introduce students to particle and astroparticle Physics. The status of the experiment and the results obtained are reported.

Recent results and performance of the multi-gap resistive plate chambers network for the EEE Project

The Extreme Energy Events (EEE) Project is devoted to the study of Extensive Atmospheric Showers through a network of muon telescopes, installed in High Schools, with the further aim of introducing young students to particle and astroparticle physics. Each telescope is a tracking detector composed of three Multi-gap Resistive Plate Chambers (MRPC) with an active area of 1.60 × 0.80m2. Their characteristics are similar to the ones built for the Time Of Flight array of the ALICE Experimentat LHC. The EEE Project started with a few pilot towns, where the telescopes have been taking data since 2008, and it has been constantly extended, reaching at present more than 50 MRPCs telescopes. They are spread across Italy with two additional stations at CERN, covering an area of around 3 × 105 km2, with a total surface area for all the MRPCs of 190m2. A comprehensive description of the MRPCs network is reported here: efficiency, time and spatial resolution measured using cosmic rays hitting the telescopes. The most recent results on the detector and physics performance from a series of coordinated data acquisition periods are also presented.

Particle IDentification with the ALICE Time-Of-Flight detector at the LHC

The main physics goal of ALICE (A Large Ion Collider Experiment) is the study of the physics of strongly interacting matter at extreme energy densities, where the formation of a new phase of matter, the Quark-GluonPlasma (QGP), is expected. One of the most important aspect of ALICE is the Particle IDentification (PID) performed by combining different identification techniques. The time measurement with the Time-Of-Flight (TOF) detector, in conjunction with the momentum and track length measured by the tracking detectors is used to calculate the particle mass in the intermediate momentum range from 0.3 up to a few GeV/c. The TOF system covers an area of 141 m2 and consists of Multi-gap Resistive Plate Chambers (MRPC), that allow excellent performances in terms of intrinsic time resolution (of the order of few tens of ps) and overall efficiency (close to 100%). The ALICE TOF system has shown very stable operation during the first three years of collisions at the LHC, reaching the design goal of 80 ps time resolution. The performance and main physics results will be reported.

Multiplicity studies and effective energy in ALICE at the LHC

In this work we explore the possibility to perform “effective energy” studies in very high energy collisions at the CERN large hadron collider (LHC). In particular, we focus on the possibility to measure in pp collisions the average charged multiplicity as a function of the effective energy with the ALICE experiment, using its capability to measure the energy of the leading baryons with the zero degree calorimeters. Analyses of this kind have been done at lower centre-of-mass energies and have shown that, once the appropriate kinematic variables are chosen, particle production is characterized by universal properties: no matter the nature of the interacting particles, the final states have identical features. Assuming that this universality picture can be extended to ion–ion collisions, as suggested by recent results from RHIC experiments, a novel approach based on the scaling hypothesis for limiting fragmentation has been used to derive the expected charged event multiplicity in AA interactions at LHC. This leads to scenarios where the multiplicity is significantly lower compared to most of the predictions from the models currently used to describe high energy AA collisions. A mean charged multiplicity of about 1000–2000 per rapidity unit (at η∼0) is expected for the most central Pb–Pb collisions at

The EEE Project: a sparse array of telescopes for the measurement of cosmic ray muons

\sqrt{s_{{\text{NN}}}} = 5.5\,\text{TeV}

EEE - Extreme Energy Events: an astroparticle physics experiment in Italian High Schools

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The highest precision proof of CPT invariance in the “nuclear binding masses”

The Extreme Energy Events (EEE) Project is meant to be the most extensive experiment to detect secondary cosmic particles in Italy. To this aim, more than 50 telescopes have been built at CERN and installed in high schools distributed all over the Italian territory. Each EEE telescope comprises three large area Multigap Resistive Plate Chambers (MRPCs) and is capable of reconstructing the trajectories of the charged particles traversing it with a good angular resolution. The excellent performance of the EEE telescopes allows a large variety of studies, from measuring the local muon flux in a single telescope, to detecting extensive air showers producing time correlations in the same metropolitan area, to searching for large-scale correlations between showers detected in telescopes tens, hundreds or thousands of kilometers apart. In addition to its scientific goal, the EEE Project also has an educational and outreach objective, its aim being to motivate young people by involving them directly in a real experiment. High school students and teachers are involved in the construction, testing and start-up of the EEE telescope in their school, then in its maintenance and data-acquisition, and later in the analysis of the data. During the last couple of years a great boost has been given to the EEE Project through the organization of simultaneous and centralized data taking with the whole telescope array. The raw data from all telescopes are transferred to CNAF (Bologna), where they are reconstructed and stored. The data are currently being analyzed, looking at various topics: variation of the rate of cosmic muons with time, upward going muons, muon lifetime, search for anisotropies in the muon angular distribution and for time coincidences between stations. In this paper an overall description of the experiment is given, including the design, construction and performance of the telescopes. The operation of the whole array is also presented by showing the most recent physics results.

The ALICE Time-Of-Flight detector: status and expected performance at the LHC startup

The Extreme Energy Events project (EEE) is aimed to study Extensive Air Showers (EAS) from primary cosmic rays of more than 1018 eV energy detecting the ground secondary muon component using an array of telescopes with high spatial and time resolution. The second goal of the EEE project is to involve High School teachers and students in this advanced research work and to initiate them in scientific culture: to reach both purposes the telescopes are located inside High School buildings and the detector construction, assembling and monitoring - together with data taking and analysis - are done by researchers from scientific institutions in close collaboration with them. At present there are 42 telescopes in just as many High Schools scattered all over Italy, islands included, plus two at CERN and three in INFN units. We report here some preliminary physics results from the first two common data taking periods together with the outreach impact of the project.

First detection of extensive air shower with the EEE experiment

The validity of CPT invariance in the field of “nuclear binding masses” has been studied for nuclei (antinuclei) with two and three nucleons (antinucleons): (d∕d) and (3He∕3He¯). It is discussed the importance of investigating the transition from the world where gluons and quarks carry their QCD colors (QGCW) to the world where gluons and quarks exist only with zero-QCD-color (QGZCW).