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The usefulness of useless science

If the scientific results financed by taxpayer money are “public goods”, is it useful or even ethical to spend billions Euros/$ to search for an elementary particle? Or to visit a Jupiter satellite and look for water on Mars? Or to observe a galaxy ad the edge of the Universe? In other words, is it useful to fund basic research? And if so, with what resources and to do what kind of science? Competition has become one of the major driving forces for research. But are we sure that the competition-driven science model is truly the best one to make useful science? More, is the very concept of knowledge changing today? The scientific method introduced by Galileo more that 400 years ago resisted at least three industrial revolutions. Are we sure is it still valid and applicable today, in the midst of the fourth industrial revolution? The answers to all these questions are not obvious, on the contrary, they can contain many surprises not all pleasant or reassuring, answers among which we will try to orient ourselves using an unconventional point of view.

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Gas detectors: general principles

Calorimetry in high-energy physics is rapidly evolving, with new specifications (e.g. higher energies, enormous particle densities) and a wide variety of technologies, both for signal creation and detection. Advances in large-area highly-segmented detectors based on, for example, silicon and scintillators, are providing possibilities for high-granularity calorimetry, providing unprecedented levels of information from particle showers. This talk focuses on one example of high-granularity calorimetry: The CMS HGCAL, being designed to replace the existing endcap calorimeters for the HL-LHC era. It is a sampling calorimeter, featuring unprecedented transverse and longitudinal readout segmentation for both electromagnetic (CE-E) and hadronic (CE-H) compartments. This will facilitate particle-flow calorimetry, where the fine structure of showers can be measured and used to enhance pileup rejection and particle identification, whilst still achieving good energy resolution. The CE-E and a large fraction of CE-H will use silicon as active detector material. The sensors will be of hexagonal shape, maximizing the available 8-inch circular wafer area. The lower-radiation environment will be instrumented with scintillator tiles with on-tile SiPM readout. This concept borrows heavily from designs produced by the CALICE collaboration – calorimetry for ILC etc. – but the challenges of such a detector at a hadron collider are considerably larger than at the ILC. In addition to the hardware aspects, the reconstruction of signals – both online for triggering and offline – is a quantum leap from existing detectors. We present the ideas behind the HGCAL, its current status including design and expected performance, and the challenges ahead.

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Gas detectors: general principles

Gas-based detectors measure the trajectories of charged particles through the ionisation electrons that are deposited in the gas. An electric field, and sometimes a magnetic field, guide(s) these electrons to amplification structures where an avalanche occurs. Avalanches produce electrons and ions and it is their motion that generates electric signals on the read-out electrodes. In this presentation we review these mechanisms.

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A Grand-Unified Nelson-Barr Model

I will discuss the structure of the Nelson-Barr approach to the strong CP Problem, and argue that these solutions can be naturally embedded into E6 Grand-Unified Theories, since the E6 fundamental contains all necessary fermions.The main benefit of the unified structure is the predictivity in the SM fermion sector, and a perfect fit to all SM observables can be obtained despite being over-constrained. Definite predictions are made for the neutrino sector, with a Dirac CP phase that is correlated to the CKM phase, allowing to test this model in the near future.

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High resolution TPC based on optically readout GEM

Large granularity and hight sensitivity commercial CMOS readout systems, open the possibility of developing particle detectors with very interesting performance for different applications, from the search of rare and exotics events, such as dark matter directional candidates, to high quality neutron/ion/hadron beam monitor, mainly for medical applications. This idea driven the CYGNUS group to exploit the gas scintillation mechanisms for starting an R&D on large TPC-based detector, equipped with a Triple GEM amplification stage optically readout. This approach, not only provides tracking capability with space resolutions of the order of tens of microns and energy measurements with a precision of about 25%, but also gives precious information allowing very good particle discrimination. Spectacular examples of captured images due to X-rays and high energy photons, cosmic muons, electrons from beam and neutrons interactions will be shown in this seminar together with quantitative analysis about the system performance.

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JUNO-Italia Meeting

Aim of the workshop: The JUNO-Italia Meeting will take place at the INFN Frascati Laboratories from March 14th to 15th, in the Salvini room (located in the ground floor of the High Energy building). The meeting will start in the morning of March 14th and will end in the early afternoon of March 15th.  

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Self focusing trailing bunch for high quality PWFA experiment at SPARC_LAB

In this work we propose a scheme for high quality beam driven plasma wakefield acceleration that exploits a combination of the wakefield generated by a low density driving bunch and an high beam loading effect of the trailing bunch. The trailing bunch is injected in a region where the focusing field generated by the driving bunch is negligible and the focusing effect derives mostly from the transverse self generated wake. The linear cold plasma fluid equations are used to derive the transverse matching conditions for the driving bunch. We develop the trailing bunch transverse matching conditions using a variant of the ion column model. The energy spread growth is derived and minimized analytically. A realistic working point to be exploited at SPARC_LAB is designed and numerically tested using simulation codes.

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Towards the EDM Polarimetry – Tests of LYSO Modules

Various symmetries are one of the most basic concepts in modern physics. Every conservation law is related to some symmetry. However, it is known that some of the symmetries are violated in weak interactions. One of the most important nature symmetries are parity (P), time reversal (T) and charge-conjugation (C). Confirmation of breaking one of those symmetries in strong interactions would have significant impact on strong interactions theory and on our understanding of the Universe. Also, particle-antiparticle asymmetry in nature is strictly connected with T symmetry breaking which should occurred in an early time of the Universe. Up to now systematic searches of T violation have been done with use of neutral particles. For charged particles, due to special difficulties of applying electric fields on charged particles, only indirect experiments, with limited precision, have been performed. Just recently, an alternative approach has been proposed. Using storage rings to accumulate polarized particles it is possible to measure electric dipole moment (EDM) – a quantity which is strictly related to T and P symmetry. To undertake measurement of EDM of charged particles, new international collaboration JEDI has been established in 2011. JEDI (Jülich Electric Dipole moment Investigations) links together researchers from all over the world. The most important institutions involved are: Forschungszentrum Julich, RWTH Aachen, Tbilisi State University, SPSC Grenoble, University of Ferrara, Jagiellonian University, Joint Institute for Nuclear Research in Dubna, Institute for Basic Science in Daejeon. The main objective of JEDI is to build a dedicated storage ring for a ...

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