Antonio De Santis

Volume 1 of the FCC Feasibility Report presents an overview of the physics case, experimental programme, and detector concepts for the Future Circular Collider (FCC). This volume outlines how FCC would address some of the most profound open questions in particle physics, from precision studies of the Higgs and EW bosons and of the top quark, to the exploration of physics beyond the Standard Model. The report reviews the experimental opportunities offered by the staged implementation of FCC, beginning with an electron-positron collider (FCC-ee), operating at several centre-of-mass energies, followed by a hadron collider (FCC-hh). Benchmark examples are given of the expected physics performance, in terms of precision and sensitivity to new phenomena, of each collider stage. Detector requirements and conceptual designs for FCC-ee experiments are discussed, as are the specific demands that the physics programme imposes on the accelerator in the domains of the calibration of the collision energy, and the interface region between the accelerator and the detector. The report also highlights advances in detector, software and computing technologies, as well as the theoretical tools/reconstruction techniques that will enable the precision measurements and discovery potential of the FCC experimental programme. The content and structure of this report are guided by the scope and priorities defined in the mandate of the FCC Feasibility Study. It is therefore not intended to serve as an exhaustive review of the full physics potential of FCC. Several topics, already covered in earlier reports such as the FCC CDR, are not reiterated here or are addressed only briefly, in alignment with the study’s focus. This volume reflects the outcome of a global collaborative effort involving hundreds of scientists and institutions, aided by a dedicated community-building coordination, and provides a targeted assessment of the scientific opportunities and experimental foundations of the FCC programme.

In the past decade, organometal halide perovskite (OMHP) semiconductors have been studied as sensors for ionization radiation and X-ray detectors, beside the well known success as photovoltaic devices. Properties such as simple single crystal growth from low-cost solution processes, high stopping power, defect-tolerance, large mobility-lifetime product and tunable bandgap make OMHP very promising materials for novel detectors. An overview of usage of perovskite for radiation detection of charged particles and electromagnetic radiation will be presented. The results of PEROV INFN project will be shown: OHMP based single crystal devices have been developed and tested with electrons from the Beam Test Facility at INFN Frascati National Laboratories, close to the minimum ionizing energy deposition. The crystal sensor can reach the single particle sensitivity with a bias voltage as low as 5 V. It also shows a good linearity of the response as a function of the number of electrons with a dynamic range of approximately 10⁴. Efforts towards the application of OMHP sensors as X-ray detectors will also be also discussed.

We report the detection of high energy electrons of some hundreds of MeV, crossing a methylammonium lead bromide single crystal device with sensitivity down to a single electron. In the device, the released energy is close to the energy released by minimum-ionizing particles. This is the first demonstration of a perovskite-based device that can be used for tracking and counting minimum-ionizing charged particles. The device reaches single particle sensitivity with a low bias voltage of 5 V. It also shows a good linearity of the response as a function of the number of electrons in a dynamic range of approximately 10⁴.

The organometal halide perovskites (OMHP) are promising candidates for fast, sensitive, and large area photodetectors. In the last decade, several techniques have been developed with complementary advantages. Film devices are thin and can be scaled to large area, but have a large number of grain‐boundaries related defects. Single bulk crystals instead have higher purity, but are thicker and can not be easily produced on large areas. In this work, a microfluidics‐assisted technique to realize a controlled growth of OMHP single crystals, in the form of microwires, directly on a conductive patterned substrates, is presented. This technique enables the realization of vertical devices with a pixelated sensor layer. The resulting devices present gain, a responsivity up to 200 AW⁻¹ and a fast rise time down to 35 µs. This is the first demonstration of a OMHP vertical device realized on a patterned substrate using microfluidics‐assisted techniques.

Splenic abscess secondary to endocarditis is a rare complication with high mortality. The treatment modality, splenectomy versus percutaneous drainage, and the best time, before or after valve replacement, are controversial. In the literature, there are only a few small case series about the subject. The objective of this study is to analyze the experience of a referral center in treating such condition. Patients with splenic abscesses due to endocarditis from 2006 to 2020 were retrospectively analyzed. Thirteen patients (mean age 46 years old, 69% male) were identified. Eight patients (62%) had at least 2 comorbidities and 5 (38%) had a history of cardiac surgery. The diagnosis was incidental in 6 (46%). The mean time of abscess diagnosis after endocarditis definition was 14 days. Six patients (46%) had at least two organ dysfunctions. The median APACHE II score was 12 overall, and 24.5 in patients who died. Six patients (46%) had a valve replacement, and in two the abscess was diagnosed postoperatively. Of the other four patients, splenectomy was performed before the cardiac operation in three and at the same time in one. Splenectomy was performed immediately in 9 (69%) patients while three patients had percutaneous drainage (23%), one of which underwent splenectomy due to drainage failure. Exclusive antibiotic treatment was performed on only one patient. The median length of hospitalization was 24 days and mortality was 46%. Splenic abscess due to endocarditis is a life-threatening condition with controversial treatment that results in a prolonged length of stay and high mortality.

DAΦNE is a lepton collider working at the energy of the φ-meson resonance, it became operational in 2000. It provided data in consecutive data-taking periods for the KLOE, DEAR and FINUDA experiments until 2006. Since 2007 it implements a new interaction scheme, the so-called “Crab-Waist” collision scheme. It is the only machine that had successfully operated this collision scheme with and without large experiment with solenoids in 2009 with the SIDDHARTA experiment and between 2014 and 2018 with the KLOE-2 experiment, respectively. It will continue operating for PADME (just using the upgraded Linac) and for Siddharta-2 in 2019-2020. Currently only few accelerator test facilities exists: the ATF2 (KEK), a top-class facility designed for the development of the International Linear Collider, CLASSE(Cornell Laboratory for Accelerator-Based Science and Education), a centre of excellence in the development of accelerator technologies located in an university campus, and ANKA (Karlsruhe), devoted to R&D of machines and applied research. The proposal of DAΦNE as a test facility (DAΦNE-TF) for accelerator physics and technology development has been presented as an open call for ideas culminated in the organization of a topical workshop in December 2018. Several lines of technological research have been identified so far for DAΦNE-TF: i) Study of low SEY (Secondary Electron Yield) elements and impedances, graphitization of chambers and other surface treatment technologies; ii) New components for accelerators (vacuum chambers, collimators, masks, kickers) and innovative beam diagnostic techniques; iii) Accelerator components realized with 3D printers; iv) High power solid state RF amplifiers; v) Wide-excursion adjustable permanent magnets; vi) High-power positron sources; vii) Components for future SLED and pulse flatness compensation; viii) Emittance manipulators; ix) Beams interacting with amorphous materials, crystals, lasers, plasma; x) Testing new methods to generate terahertz coherent radiation. In this contribution, a selection of the different activities proposed during a dedicated workshop held in Frascati Laboratories in December 2018 will be summarized.