The EEE (Extreme Energy Events) Project is an experiment for the detection of cosmic ray muons by means of a sparse array of telescopes, each made of three Multigap Resistive Plate Chambers (MRPC), distributed over all the Italian territory and at CERN. The main scientific goals of the Project are the investigation of the properties of the local muon flux, the detection of Extensive Air Showers (EAS) and the search for long-distance correlations between far telescopes. The Project is also characterized by a strong educational and outreach aspect since the telescopes are managed by teams of students and teachers who had previously constructed them at CERN. 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, which currently consists of more than 50 telescopes, is also presented by showing the most recent physics results.

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 validity of CPT invariance in the field of “nuclear binding masses” has been studied for nuclei (antinuclei) with two and three nucleons (antinucleons): [Formula: see text] and [Formula: see text]. 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).

Distributions of secondary cosmic muons were measured by the Multigap Resistive Plate Chambers (MRPC) telescopes of the Extreme Energy Events (EEE) Project, spanning a large angular and temporal acceptance through its sparse sites, to test the possibility to search for any anomaly over long runs. After correcting for the time exposure and geometrical acceptance of the telescopes, data were transformed into equatorial coordinates, and equatorial sky maps were obtained from different sites on a preliminary dataset of 110M events in the energy range at sub-TeV scale.

The production of D 0, D *+, D +, \( D_s^{+} \) and \( \Lambda_c^{+} \) charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb−1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the stangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum p T > 3.8 GeV and pseudorapidity |η| < 1.6. The charm fragmentation fractions are compared to previous results from HERA and from e + e − experiments. The data support the hypothesis that fragmentation is independent of the production process.

Measurements of neutral current cross sections for deep inelastic scattering in ${e}^{+}p$ collisions at HERA with a longitudinally polarized positron beam are presented. The single-differential cross-sections $d\ensuremath{\sigma}/d{Q}^{2}$, $d\ensuremath{\sigma}/dx$ and $d\ensuremath{\sigma}/dy$ and the reduced cross section $\stackrel{\texttildelow{}}{\ensuremath{\sigma}}$ are measured in the kinematic region ${Q}^{2}>185\text{ }\text{ }{\mathrm{GeV}}^{2}$ and $y<0.9$, where ${Q}^{2}$ is the four-momentum transfer squared, $x$ the Bjorken scaling variable and $y$ the inelasticity of the interaction. The measurements are performed separately for positively and negatively polarized positron beams. The measurements are based on an integrated luminosity of $135.5\text{ }\text{ }{\mathrm{pb}}^{\ensuremath{-}1}$ collected with the ZEUS detector in 2006 and 2007 at a center-of-mass energy of 318 GeV. The structure functions ${\stackrel{\texttildelow{}}{F}}_{3}$ and ${F}_{3}^{\ensuremath{\gamma}Z}$ are determined by combining the ${e}^{+}p$ results presented in this paper with previously published ${e}^{\ensuremath{-}}p$ neutral current results. The asymmetry parameter ${A}^{+}$ is used to demonstrate the parity violation predicted in electroweak interactions. The measurements are well described by the predictions of the Standard Model.

The exclusive electroproduction of two pions in the mass range 0.4<M ππ <2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb−1. The analysis was carried out in the kinematic range of 2<Q 2<80 GeV2, 32<W<180 GeV and |t|<0.6 GeV2, where Q 2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, |F(M ππ )|, assuming that the studied mass range includes the contributions of the ρ, ρ′ and ρ′′ vector-meson states. The masses and widths of the resonances were obtained and the Q 2 dependence of the cross-section ratios σ(ρ′→ππ)/σ(ρ) and σ(ρ′′→ππ)/σ(ρ) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e + e −→π + π −.

The production of isolated high-energy photons accompanied by jets has been measured in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 326 pb(-1). Measurements were made for exchanged photon virtualities Q(2), in the range 10 to 350 GeV2. The photons were measured in the transverse-energy and pseudorapidity ranges 4 < E-T(gamma) < 15 GeV and -0.7 < eta(gamma) < 0.9, and the jets were measured in the transverse-energy and pseudorapidity ranges 2.5 < E-T(jet) < 35 GeV and -15< eta(jet) < 1.8. Differential cross sections are presented as functions of these quantities. Perturbative QCD predictions give a reasonable description of the shape of the measured cross sections over most of the kinematic range but the absolute normalisation is typically in disagreement by 20-30%. (c) 2012 Elsevier B.V. All rights reserved.

Abstract Scaled momentum distributions for the strange hadrons $ K_{\text{S}}^0 $ and $ \Lambda /\bar{\Lambda } $ were measured in deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 330 pb−1. The evolution of these distributions with the photon virtuality, Q 2, was studied in the kinematic region 10 < Q 2 < 40000 GeV2 and 0.001 < x < 0.75, where x is the Bjorken scaling variable. Clear scaling violations are observed. Predictions based on different approaches to fragmentation were compared to the measurements. Leading-logarithm parton-shower Monte Carlo calculations interfaced to the Lund string fragmentation model describe the data reasonably well in the whole range measured. Next-to-leading-order QCD calculations based on fragmentation functions, FFs, extracted from e + e − data alone, fail to describe the measurements. The calculations based on FFs extracted from a global analysis including e + e −, ep and pp data give an improved description. The measurements presented in this paper have the potential to further constrain the FFs of quarks, anti-quarks and gluons yielding $ K_{\text{S}}^0 $ and $ \Lambda /\bar{\Lambda } $ strange hadrons.

This paper describes the main quality assurance tests developed to check the status of the ALICE TOF SuperModules and included in the commissioning procedures. Some preliminary results concerning these tests on the first two installed super modules are presented as well.

Bose–Einstein correlations of pairs of identical charged pions produced in hadronic Z decays are analyzed in terms of various parametrizations. A good description is achieved using a Lévy stable distribution in conjunction with a model where a particle’s momentum is correlated with its space–time point of production, the τ-model. Using this description and the measured rapidity and transverse momentum distributions, the space–time evolution of particle emission in two-jet events is reconstructed. However, the elongation of the particle emission region previously observed is not accommodated in the τ-model, and this is investigated using an ad hoc modification.

Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb−1. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, \(p_{\mathrm {T}}^{\mathrm{jet}}\), and pseudorapidity, η jet, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions.

This work reports a Monte Carlo study of Δ++ resonance production and decay in p-p collisions at \( \sqrt{{s}}\) = 10 TeV. For this study case, the ALICE detector at the LHC collider has been chosen. The Δ++ → πp decay is studied using a simulation of the full ALICE detector response. Special care is taken to extract the signal using the event-mixing technique for background estimation. Results from a 4.8 million events sample are presented. This number of events corresponds to a few days data-taking at the nominal acquisition rate and luminosity.

Beauty production in deep inelastic scattering with events in which a muon and a jet are observed in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb^-1. The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative to the jet. The cross section for beauty production was measured in the kinematic range of photon virtuality, Q^2 > 2 Gev^2, and inelasticity, 0.05 < y < 0.7, with the requirement of a muon and a jet. Total and differential cross sections are presented and compared to QCD predictions. The beauty contribution to the structure function F_2 was extracted and is compared to theoretical predictions.

The proton-dissociative diffractive photoproduction of J / ψ mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb −1 . The cross section is presented as a function of the photon-proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compared to perturbative QCD calculations.

Deeply virtual Compton scattering, gamma*p -> gamma p, has been measured in e(+)p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb(-1). Cross sections are presented as a function of the photon virtuality, Q(2), and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q(2) > 1.5GeV(2) and 40 < W < 170GeV. A subsample of events in which the scattered proton is measured in the leading proton spectrometer, corresponding to an integrated luminosity of 31.3 pb(-1), is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex.

The Extreme Energy Events (EEE) project is devoted to search extremely high energy cosmic rays, by means of an array of hodoscopes distributed over the italian territory. These stations are based on the use of Multigap Resistive Plate Chambers (MRPC), that have excellent time resolution and good tracking capability. They are installed in selected secondary school institutes, where students are involved in the research work. In this article the analysis of the first extensive air shower detected is presented.