Study of inelastic processes in proton-proton collisions at the LHC with the TOTEM experiment

The TOTEM experiment, located into the CMS cavern at the CERN Large Hadron Collider (LHC), is one of the six experiments that are investigating high energy physics at this new machine. In particular TOTEM has been designed for TOTal cross-section, Elastic scattering and diffraction dissociation Measurements. The total proton-proton cross-section will be measured with the luminosity-independent method based on the Optical Theorem. This method will allow a precision of 1÷2% at the center of mass energy of 14 TeV. In order to reach such a small error it is necessary to study the p-p elastic scattering cross-section ( dσ/dt ) down to |t| ∼ 10^−3 GeV^2 (to evaluate at best the extrapolation to t = 0) and, at the same time, to measure the total inelastic interaction rate. For this aim, elastically scattered protons must be detected at very small angles with respect to the beam while having the largest possible η coverage for particle detection in order to reduce losses of inelastic events. In addition, TOTEM will also perform studies on elastic scattering with large momentum transfer and a comprehensive physics programme on diffractive processes (partly in cooperation with CMS), in order to have a deeper understanding of the proton structure. For these purposes TOTEM consists in three different sub-detectors: two gas based telescopes (T1 and T2) for the detection of inelastic processes with a coveragein the range of 3.1 ≤ |η| ≤ 6.5 on both sides of the interaction point 5 (IP5), and silicon based detectors for the elastically scattered protons, located in special movable beampipe insertions called Roman Pots (RPs), at about 147 m and 220 m from the interaction point. The work done by the candidate reported in this thesis mainly consists in three subjects: the tuning of the simulation for the T2 inelastic telescope, the study of the noise of the T2 detector and a preliminary study concerning the detection performance for inelastic events. In the following, the first chapter describes the TOTEM experiment and the LHC machine, with a particular attention to the T2 telescope and its analysis software, being of critical importance for the work of this thesis. The second chapter introduces the physics programme of the TOTEM experiment. Chapter three describes the tuning of Geant4 parameters and the improvement of the simulated geometry for the T2 detector, while chapter four summarizes an important and demanding study on the detector noise. Finally in chapter five some preliminary studies on inelastic processes are presented, in order to show the perspective for the TOTEM experiment to perform the measurement of the inelastic cross section in a wide kinematic range

Two New Measures of Bankruptcy Efficiency

This study is aimed at developing new empirical models for evaluating the efficiency of bankruptcy legislations. The paper is divided in three parts. In the first part, we analyze from a conceptual point of view the effects on debtor firms of the lack of creditors' powers in bankruptcy. In the second part, we develop a new rating method for bankruptcy legislations according to their degree of creditors protection and apply it to five European countries. In the third part, we introduce a new approach for empirically estimating the efficiency of bankruptcy legislation based on the cost of banking credit and we test it on the Italian case. In particular, the unprecedented tool being used in the third section consists of the New Basel Capital Accord, i.e. the capital adequacy regulatory framework that is about to be put into effect as of the end of 2006

CALET on the International Space Station: new direct measurements of cosmic-ray iron and nickel

The Calorimetric Electron Telescope (CALET), in operation on the International Space Station since 2015, collected a large sample of cosmic-ray over a wide energy interval. Approximately 20 million triggered events per month are recorded with energies > 10 GeV. The instrument identifies the charge of individual elements up to nickel and beyond and, thanks to a homogeneous lead-tungstate calorimeter, it measures the energy of cosmic-ray nuclei providing a direct measurement of their spectra. Iron and nickel spectra are a low background measurement with negligible contamination from spallation of higher mass elements. Iron and nickel nuclei play a key role in understanding the acceleration and propagation mechanisms of charged particles in our Galaxy. In this contribution a direct measurement of iron and nickel spectra, based on more than five years of data, are presented in the energy range from 10 GeV/n to 2 TeV/n and from 8.8 GeV/n to 240 GeV/n, respectively. The spectra are compatible within the errors with a single power law in the energy region from 50 GeV/n to 2 TeV/n and from 20 GeV/n to 240 GeV/n, respectively. Systematic uncertainties are detailed and the nickel to iron flux ratio is presented. This unprecedented measurement confirms that both elements have very similar fluxes in shape and energy dependence, suggesting that their origin, acceleration, and propagation might be explained invoking an identical mechanism in the energy range explored so far

CALET on the International Space Station: a precise measurement of the iron spectrum

The Calorimetric Electron Telescope (CALET) was launched on the International Space Station in 2015 and since then has collected a large sample of cosmic-ray charged particles over a wide energy. Thanks to a couple of layers of segmented plastic scintillators placed on top of the detector, the instrument is able to identify the charge of individual elements from proton to iron (and above). The imaging tungsten scintillating fiber calorimeter provides accurate particle tracking and the lead tungstate homogeneous calorimeter can measured the energy with a wide dynamic range. One of the CALET scientific objectives is to measure the energy spectra of cosmic rays to shed light on their acceleration and propagation in the Galaxy. By the observation in first five years, a precise measurement of the iron spectrum is now available in the range of kinetic energy per nucleon from 10 GeV/n to 2 TeV/n. The CALET’s result with a description of the analysis and details on systematic uncertainties will be illustrated. Also, a comparison with previous experiments’ results is given

CALET measurements with cosmic nuclei: expected performances of tracking and charge identification

CALET is a space mission currently in the final phase of preparation for a launch to the International Space Station (ISS), where it will be installed on the Exposed Facility of the Japanese Experiment Module (JEM-EF). In addition to high precision measurements of the electron spectrum, CALET will also perform long exposure observations of cosmic nuclei from proton to iron and will detect trans-iron elements with a dynamic range up to Z = 40. The energy measurement relies on two calorimeter systems: a fine grained imaging calorimeter (IMC) followed by a total absorption calorimeter (TASC) for a total thickness of 30 X0 and 1.3 proton interaction length. A dedicated module (a charge detector, CHD), placed at the top of the apparatus, identifies the atomic number Z of the incoming cosmic ray. In this paper, the IMC performances in providing tracking capabilities and a redundant charge measurement by multiple dE dx samples are studied for the case of proton and He identification with a preliminary version of the analysis. The CALET mission is funded by the Japanese Space Agency (JAXA), the Italian Space Agency (ASI), and NASA

Ultrasound- versus landmark-guided subclavian vein catheterization: a prospective observational study from a tertiary referral hospital

This was a single-center, observational, prospective study designed to compare the effectiveness of a real-time, ultrasound- with landmark-guided technique for subclavian vein cannulation. Two groups of 74 consecutive patients each underwent subclavian vein catheterization. One group included patients from intensive care unit, studied by using an ultrasound-guided technique. The other group included patients from surgery or emergency units, studied by using a landmark technique. The primary outcome for comparison between techniques was the success rate of catheterization. Secondary outcomes were the number of attempts, cannulation failure, and mechanical complications. Although there was no difference in total success rate between ultrasound-guided and landmark groups (71 vs. 68, p\u2009=\u20090.464), the ultrasound-guided technique was more frequently successful at first attempt (64 vs. 30, p\u2009<\u20090.001) and required less attempts (1 to 2 vs. 1 to 6, p\u2009<\u20090.001) than landmark technique. Moreover, the ultrasound-guided technique was associated with less complications (2 vs. 13, p\u2009<\u20090.001), interruptions of mechanical ventilation (1 vs. 57, p\u2009<\u20090.001), and post-procedure chest X-ray (43 vs. 62, p\u2009=\u20090.001). In comparison with landmark-guided technique, the use of an ultrasound-guided technique for subclavian catheterization offers advantages in terms of reduced number of attempts and complications

The Impact of Crystal Light Yield Non-Proportionality on a Typical Calorimetric Space Experiment: Beam Test Measurements and Monte Carlo Simulations

Calorimetric space experiments were employed for the direct measurements of cosmic-ray spectra above the TeV region. According to several theoretical models and recent measurements, relevant features in both electron and nucleus fluxes are expected. Unfortunately, sizable disagreements among the current results of different space calorimeters exist. In order to improve the accuracy of future experiments, it is fundamental to understand the reasons of these discrepancies, especially since they are not compatible with the quoted experimental errors. A few articles of different collaborations suggest that a systematic error of a few percentage points related to the energy-scale calibration could explain these differences. In this work, we analyze the impact of the nonproportionality of the light yield of scintillating crystals on the energy scale of typical calorimeters. Space calorimeters are usually calibrated by employing minimal ionizing particles (MIPs), e.g., nonshowering proton or helium nuclei, which feature different ionization density distributions with respect to particles included in showers. By using the experimental data obtained by the CaloCube collaboration and a minimalist model of the light yield as a function of the ionization density, several scintillating crystals (BGO, CsI(Tl), LYSO, YAP, YAG and BaF2) are characterized. Then, the response of a few crystals is implemented inside the Monte Carlo simulation of a space calorimeter to check the energy deposited by electromagnetic and hadronic showers. The results of this work show that the energy scale obtained by MIP calibration could be affected by sizable systematic errors if the nonproportionality of scintillation light is not properly taken into account

CALOCUBE: An approach to high-granularity and homogenous calorimetry for space based detectors

Future space experiments dedicated to the observation of high-energy gamma and cosmic rays will increasingly rely on a highly performing calorimetry apparatus, and their physics performance will be primarily determined by the geometrical dimensions and the energy resolution of the calorimeter deployed. Thus it is extremely important to optimize its geometrical acceptance, the granularity, and its absorption depth for the measurement of the particle energy with respect to the total mass of the apparatus which is the most important constraint for a space launch. The proposed design tries to satisfy these criteria while staying within a total mass budget of about 1.6 tons. Calocube is a homogeneous calorimeter instrumented with Cesium iodide (CsI) crystals, whose geometry is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is more than adequate for optimal electromagnetic particle identification and energy measurement, whilst the interaction length is at least sufficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. The design forms the basis of a three-year R&D activity which has been approved and financed by INFN. An overall description of the system, as well as results from preliminary tests on particle beams will be described

Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere

The atmospheres of gaseous giant exoplanets orbiting close to their parent stars (hot Jupiters) have been probed for nearly two decades. They allow us to investigate the chemical and physical properties of planetary atmospheres under extreme irradiation conditions. Previous observations of hot Jupiters as they transit in front of their host stars have revealed the frequent presence of water vapour and carbon monoxide in their atmospheres; this has been studied in terms of scaled solar composition under the usual assumption of chemical equilibrium. Both molecules as well as hydrogen cyanide were found in the atmosphere of HD 209458b, a well studied hot Jupiter (with equilibrium temperature around 1,500 kelvin), whereas ammonia was tentatively detected there and subsequently refuted. Here we report observations of HD 209458b that indicate the presence of water (H2O), carbon monoxide (CO), hydrogen cyanide (HCN), methane (CH4), ammonia (NH3) and acetylene (C2H2), with statistical significance of 5.3 to 9.9 standard deviations per molecule. Atmospheric models in radiative and chemical equilibrium that account for the detected species indicate a carbon-rich chemistry with a carbon-to-oxygen ratio close to or greater than 1, higher than the solar value (0.55). According to existing models relating the atmospheric chemistry to planet formation and migration scenarios, this would suggest that HD 209458b formed far from its present location and subsequently migrated inwards. Other hot Jupiters may also show a richer chemistry than has been previously found, which would bring into question the frequently made assumption that they have solar-like and oxygen-rich compositions.Comment: As part of the Springer Nature Content Sharing Initiative, it is possible to access a view-only version of this paper by using the following SharedIt link: https://rdcu.be/cifr