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Search for exotic hadrons with the CMS experiment
No full textTetraquarks are exotic hadrons made of four quarks whose existence is predicted by Quantum Chromodynamics. Tetraquarks have been observed by several experiments, like BaBar and LHCb. However, their internal structure is not
fully understood, and more experimental observations are needed. This analysis extends, for the first time, the search for tetraquarks made of four bottom quarks in final state 2μ2e (X(bb¯b¯b) → ΥΥ → μ+μ−e+e−), exploiting data collected in 2018 by the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC). They correspond to an integrated luminosity of 59.97 fb−1 for proton-proton collisions with a center of mass energy of √s = 13 TeV. The main physical observable is the di-Υ invariant mass spectrum of the 2μ2e system whose signal distribution is expected to peak near the tetraquark mass. Results of this analysis are presented as expected limit on the process cross section as a function of tetraquark mass in the range between 17–30 GeV
Light Dark Matter searches with the BDX-MINI experiment
No full textBDX-MINI is the first modern electron beam dump experiment
aiming to probe Light Dark Matter in the MeV-GeV mass range. In the experiment, Dark Matter is expected to be produced by the interaction of CEBAF high intensity electron beam with JLab experimental Hall-A beam dump and detected by the BDXMINI detector, located 26 m downstream. This paper describes the detector used in the experiment and reports details of (blind) data analysis. Since no positive results
were found, an exclusion limit was extracted from data collected in 2020 run
The gravitational field of isolated objects in quadratic gravity
No full textWhen describing gravity at high energies it is natural to introduce terms quadratic in the curvature as first corrections to the Einstein-Hilbert action. Static, spherically symmetric classical solutions are studied in the case of the quantum-motivated R + R2 + CμνρσCμνρσ theory. In contrast with the case of General Relativity, where the metric is forced to be the Schwarzschild one, a large
spectrum of solutions with different gravitational potentials has been found. It is shown how these solutions populate the parameter space of the theory, and some
possible phenomenological implications of this modified potential are discussed
Cobalt on nickel surfaces and the role of carbide on its stability
No full textTransition metal atoms are commonly used in catalysis and photocatalysis, but their potential reactivity reduces with aggregation and alloying. We investigate in particular whether Cobalt adatoms float on Ni surfaces or dissolve
into the metal. Density functional theory calculations have been performed in order to evaluate the stability of different Cobalt adsorption configurations on Nickel
surfaces, mainly at (100) terraces and steps, and the relevant energy barriers for diffusion on terraces and across steps, segregation and dissolution into the substrate. The simulations have been compared with variable temperature scanning tunneling microscopy and low energy electron diffraction. The results show that the Cobalt
adatoms and small aggregates are unstable with respect to the formation of Co-Ni alloys, but the presence of a carbide monolayer on Ni surface improve their stability
Photonic jets writing of quantum dots with intrinsic photoluminescence collection enhancement(∗)
No full textOwing to their ability to generate non-classical light states, quantum dots (QDs) are ideal candidates for the large-scale deployment of quantum information technologies. However, semiconductor QDs alone lack the high photon
collection efficiency needed by these technologies. In this work we present a laser writing technique for the fabrication of QDs self-aligned with dielectric microspheres, which, in turn, increase the collection efficiency of the system of a factor 7.3 ± 0.7. That technique exploits the use of photonic nanojets, produced by illuminating the microspheres, to selectively break the N-H bond in a GaAs/GaAs1−xNx:H/GaAs quantum well, thus fabricating GaAs1−xNx QDs
Validating gas dispersion modelling at La Solfatara (Campi Flegrei, South Italy)
No full textProbabilistic hazard assessments of volcanic gases need to account for the natural variability associated to aspects such as weather conditions, source location, emission rate, and gas species. In order to quantitatively carry out these
assessments, computational tools for gas dispersal need to be validated to demonstrate the reliability of the model results. Here we provide an exemplificative gas dispersal model validation at La Solfatara (a maar crater within Campi Flegrei caldera) which hosts one of the largest and hazardous fumarolic sites of the world, by using a workflow designed for automating the simulation strategy for probabilistic gas hazard assessments. This represents the first fundamental step towards gas hazard quantification in the area
Status update: Asymptotically safe gravity-matter systems
No full textThe field of asymptotically safe matter-gravity systems is maturing from the study of simple toy models to the exploration of sectors of the Standard Model and beyond. This status update reviews the current state of the art and
points out open questions and future perspectives
Temperatures of compound nuclei produced in complete and incomplete fusion and the role of neutron excess
No full textThe role of neutron excess in the nuclear equation of state is important in many systems from the microscopic to the astronomical, and yet the asymmetry energy remains the largest source of uncertainty in the equation of state. We
continue our study of the asymmetry dependence of nuclear caloric curve, measuring evaporation of light charged particles from compound nuclei produced Kr + C fusion reactions. The composition and excitation of the compound nuclei are varied by varying the isotope and kinetic energy of the krypton projectile. Temperatures are extracted with kinetic and chemical probes. The more neutron-rich compound
nuclei exhibit higher temperatures than the less neutron-rich compound nuclei. We discuss this in light of previous experimental efforts theoretical predictions
Tra terminologia e lessicologia: un "ponte" informatico" nel percorso scientifico di Giovanni Adamo
Get PDFOne year after his untimely passing, the Authors remember Giovanni Adamo and his original and impactful scholarly contribution to the field of terminology and lexicology, in the context of the close relationship with Humanities computing
Dallo studio alla ricostruzione: fonti e metodologie per la rappresentazione di un contesto perduto. Il caso dei granai e fienili al complesso di Domiziano (Foro Romano-Palatino)
Get PDFNowadays, new surveying technologies and 3D modelling techniques allow high precision reconstructions of lost historical contexts. Indeed, in recent times, modern and broader perspectives of the archaeological research push to analyze post-ancient contexts with stratigraphic methods. The case of study concerns granaries and barns erected in the Early-modern age on the ancient ruins belonging to the Complex of the Emperor Domitian (Roman Forum-Palatine). At the end of 19th century, these modern structures were demolished. Now, significant traces on the ancient architectures (3D photogrammetry survey) and the large number of iconographic sources (organized in a digital database) give the possibility to reconstruct this block of vernacular buildings, with significant implications both on the scientific documentation and on the dissemination