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Offline primary vertex reconstruction for heterogeneous architectures
Get PDFThe future development projects for the Large Hadron Collider will bring nominal luminosity increase, with the ultimate goal of reaching a peak luminosity of 5×1034 cm−2 s
−1. This would result in up to 200 simultaneous proton
collisions (pileup), posing significant challenges for the CMS detector reconstruction. The CMS primary vertex (PV) reconstruction is a two-step procedure consisting of
vertex finding and fitting. First, the Deterministic Annealing algorithm clusters tracks coming from the same interaction vertex. Secondly, an Adaptive Vertex Fit
computes the best estimate of the vertex position in three or four dimensions. For High Luminosity LHC (HL-LHC) conditions, the reconstruction of PVs is expected to be extremely time expensive (up to 6% of reconstruction time). In this work, studies are presented on the rethinking and porting of PV reconstruction algorithms for heterogeneous architectures to exploit parallelization techniques to significantly reduce the processing time. We will show the results obtained focusing on computing and physics performance for HL-LHC conditions
Dark Sector searches in final states with prompt neutral particles with the ATLAS detector
Get PDFThis work investigates the possibility that dark matter could be produced at the LHC, under the assumption that it is weakly coupled to the ordinary matter via a mixing parameter ε and that it constitutes a new sector of particles. Under the assumption of a neutral mediator, the dark photon, that decays promptly inside the ATLAS innermost detector volume, the lepton-jet signature, in which
collimated leptons are reconstructed as a single object, is exploited. This work, based on the full Run-2 dataset, aims at extending the sensitivity of the previous Run-1 search to smaller branching ratios of the Higgs boson decaying to dark photons and to a wider dark photon mass range in the ε > 10−5 region
Timing performance of thin Low Gain Avalanche Detectors (LGADs)
Get PDFThe first very thin Low Gain Avalanche Detectors (LGADs) pro
duced by Fondazione Bruno Kessler (FBK) were tested in a beam test setup at PS, CERN. The study focuses on LGADs with nominal thicknesses of 25 μmand 35 μm and an area of 1 ×1mm2. Several measurements were carried out and a summary of the timing performance is reported here. A time resolution of approx imately 25 and 22 ps at voltages of 120 and 240 V was reached by 25 and 35 μm thick LGADs, respectively. These results demonstrate the potential of this new generation of LGADs
Joint negative muon data analysis and Monte Carlo simulation methods for the characterization of thin layers
Get PDFMusoni c atom X-ray Emission Spectroscopy (μXES) is a novel tech- nique in the broad field of non-destructive methods for cultural heritage analysis. It relies on the interaction of a probe of negative muons with matter and following emission of X-ray radiation. Since the muon mass is about 207 times bigger than the electron, these emitted X-rays are highly energetic and are characteristic of the emitting atom, making it possible to cover a wide part of the periodic table (from lithium to uranium). The multi-elemental range, a negligible self-absorption of the X-rays and very low residual activity left in the sample after irradiation make μXES a very powerful probe for material characterization. In addition, by coupling the data analysis with Monte Carlo simulation methods, it is possible to asses the depth of the layers that are present in a given sample. In this work, preliminary results of the analysis on two gilded surfaces are reported
Copropagating schemes for dielectric laser accelerators
Get PDFf of principle electrons laser acceleration experiments, car- ried out by several groups, have demonstrated accelerating gradients larger than 200 MeV/m. However, the adopted configurations (free space coupled gratings, dual pillar, phase reset devices) cannot be easily scaled in length, because they require a transversely incident laser light, impinging laterally along the whole in- teraction dielectric structure. In this paper, extended interaction structures with collinear propagation of the accelerating electromagnetic field and the particles to be accelerated are described: both 2D and 3D photonic-crystals-based structures and slot hollow-core waveguides are compared in terms of accelerating gradient and characteristic interaction impedance, a fundamental quality parameter for Dielectric Laser Accelerators (DLAs)
The effects of smoking on the tear film and on soft contact lenses
Get PDFSmoking is frequently associated with systemic and ocular diseases. Considering the fundamental role in eye health of the precorneal tear fluid, its analysis could offer unique contributions to gather information on ocular status. Smoking has a negative effect on tear film stability and quality by affecting different components, which can be assessed only by multiple tests. In addition, smoking is a risk factor for microbial keratitis and corneal infiltrates in contact lens (CL) wearers. In this work, the interaction between nicotine and CL materials is analysed. CLs belonging to the FDA groups I, II, IV, and V were incubated in a nicotine solution for 24 hours. The amount of absorbed nicotine per CL was monitored by ultraviolet spectrophotometry, normalizing it to the mass of the hydrated CL. Group IV and V CLs displayed the highest and lowest nicotine absorption, respectively. The results suggest that CL affinity for nicotine could be ascribed to the interaction between the positive charge of nicotine pyrrolidine nitrogen and the negative charges of the CLs
Cosmos-lovers' symphonic guide to the galaxy
Get PDFIn the past, several authors highlighted analogies between classical music and astronomy fundamentals, comparing acoustic and melody features with the characteristics of cosmic objects. However, we believe that a more profound con- nection between the two disciplines can be explored, considering the harmonic struc- ture and the formal arrangement of symphonic compositions. This new approach can provide a more insightful understanding of both music theory and astrophysics, inspiring both music and physics lovers. In this contribution, we present the format and content of the event “Cosmos-lovers’ symphonic guide to the galaxy”, a show imagined and conceived on the basis of this new perspective on the valuable bino- mial of music and astronomy. During this event, astrophysicist Simone Iovenitti and orchestra conductor Ruben Jais present the analogies between the universe’s evolution and symphonies by Rebel, Rameau, and Ives, played by the Symphonic Orchestra of Milan. Images, animations, and videos are projected in the concert hall both during explanations and the live performance, ensuring a very immersive experience to the audience
An approach to research-based design of teaching-learning sequences in the context of physics education: Theoretical frameworks, pedagogical methods, and examples of Data Analysis
Get PDFIn this paper we discuss an example of the research approaches practiced at the University of Palermo Physics Education Research Group (UoP- PERG). Particularly, we discuss the design and development with groups of high school students of two Teaching-Learning Sequences (TLSs) on surface phenomena in liquids, and the data collection and analysis methods. In the introduction, we briefly discuss the educational reconstruction model, that we use as a theoretical framework for the designing of the TLSs, and a pedagogical methodology that in the last years has gained consensus among educators, i.e., active learning. Some considerations on active learning pedagogical and cognitive psychology foundations are also made. The main aim of the TLSs is to improve students’ learning of surface phenomena, a topic that is quite relevant in Physics and other scientific and technical fields. We provide a research-based, conceptual scheme of what we mean by “improvement of students’ learning”, and present the TLSs phases, that are based on the well-known inquiry- and investigation-based learning approaches, that are science-specific applications of the general idea of active learning. Then, we describe some methods we use in our researches to collect and give an example of the data analysis needed to study the progression of student learning, with respect to the conceptual scheme provided, and of some of the results obtained
Inducing the construction of formal axioms of Quantum Mechanics and fostering their comprehension by high school students: The effectiveness of a conceptual approach
Get PDFTaking as a paradigmatic example an educational reconstruction of Quantum Mechanics (QM), we discuss the approach and general research lines followed by the Physics Education Research Group of the Universities of Milan and Rome. Our choice is prompted by the fact that through QM students can lay out the structure of a new grammar, which is necessary for the presentation of any quantum theory (in particular, Quantum Field Theory) in high school. In particular, we discuss the results of a 15-hour pilot experimentation made in A.Y. 2021–2022, with high school students and teachers. The results obtained are highly encouraging since they appear to indicate that the introduction of formal aspects of QM in Italian high school is possible with more than satisfying learning