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## The rainbow ion-solid interaction potential

This talk will be devoted to the rainbow proton-silicon interaction potential. We show that it can be obtained as a modification of the corresponding Molière proton-silicon interaction potential by applying the theory of crystal rainbows [1] and the experimental high-resolution angular pattern of 2 MeV protons transmitted through a 55 nm thick Si crystal [2]. The fitting procedure has been performed so that the peripheral rainbow line, generated by the corresponding ZBL interaction potential [3], and the central rainbow line, generated by the Molière interaction potential used by Krause et al. [4], were at the same time well approximated by the rainbow lines generated by the rainbow interaction potential. As a result, the theoretical angular distributions of transmitted protons are in excellent agreement with the corresponding experimental ones. Possible applications of the rainbow ion–atom interaction potential has been discussed. [1] S. Petrović, L. Miletić, and N. Nešković, Theory of rainbows in thin crystals: The explanation of ion channeling applied to Ne10+ ions transmitted through a thin crystal, Phys. Rev. B 61, 184 (2000). [2] M. Motapothula, S. Petrović, N. Nešković, Z. Y. Dang, M. B. H. Breese, M. A. Rana, and A. Osman, Origin of ringlike angular distributions observed in rainbow channeling in ultrathin crystals, Phys. Rev. B 86, 205426 (2012). [3] J. F. Ziegler, J. P. Biersack and U. Littmark, The stopping and range of ions in solids (Pergamon Press, 1985). [4] H. F. Krause, J. H. Barrett, S. Datz, P. F. Dittner, N. L. Jones, J. Gomez del ...

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## Injector design for the MariX-FEL project

The INFN-Milan proposes the design of a Multi-disciplinary Advanced Infra-structure for Research with X-rays (MariX) to be installed in the future Technological Pole of the University of Milan, by the Expo area. MariX will be an FEL (free electron laser) light source and it will produce highly coherent X-rays, in the range 1-5 keV, with ultra-short pulses (10-50 fs) and a repetition rate up to 1MHz. At the same time, MariX will host a compact monochromatic X-ray source, called BriXS, by using an inverse-Compton scattering scheme, with energies up to 150 keV and a repetition rate of 100 MHz (continuous-wave CW operation) that will generate fluxes up to 1013 photons per second. In this presentation, the main guidelines for the electron injector will be discussed as well as the choices for the main operating layouts and parameters for CW (continuous-wave) operation, such as the electron gun and the accelerating linear accelerators.

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## Cosmological inflation in the early universe

Inflation is a phase of accelerated expansion, taking place at very high energy in the early Universe. During this epoch, inhomogeneities are generated on cosmological scales from the amplification of quantum fluctuations of the gravitational and matter fields, that are stretched to distances of astrophysical interest today. Inflation has become a very active field of research because the energy scales involved during this early epoch are many orders of magnitude greater than those accessible in particle physics experiments. The early Universe is thus one of the most promising probes to test far beyond standard model physics. I will review the current theoretical and observational status of cosmic inflation, and discuss what we may learn from future experiments.

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## Beam diagnostics for plasma wake-ﬁeld acceleration and betatron radiation

One of the main goals of the SPARC Lab activities is to deliver high qual- ity electron beam accelerated in plasma. The quality of the beam in plasma basedacceleration depends on the proper matching of the beam before the injection to the plasma and after the acceleration. In order to succeed in both of thosetasks a proper diagnostics system is a paramount. Thus in this work our main objective is creation/modification of the conventional diagnostics tools to meet the requirements for the plasma based acceleration. Namely, the matching of the beam to the plasma requires sub-micron resolution in transverse and f s resolution in longitudinal directions. Alongside with conventional tools at SPARC Lab we investigate an alter- native possibilities for diagnostics. Duringthe plasma wake-field acceleration the electron beams emit so called betatron radiation (BR). Since the param- eters of BR (e.g. spectrum) depend on parameters of the beam, we study the possibilities to use BR in order to reconstruct certain parameters of the beam – its transverse size for example

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## XIX FRASCATI SPRING SCHOOL “BRUNO TOUSCHEK” in Nuclear, Subnuclear and Astroparticle Physics

The XIX LNF Spring School “Bruno Touschek” in Nuclear, Subnuclear and Astroparticle Physics will take place at the INFN, Laboratori Nazionali di Frascati, Italy from Monday, May 7th to Friday, May 11th, 2018. The School is intended for graduate students and post-doctoral fellows in theoretical and experimental high-energy physics. The 2018 edition of the School includes lectures on selected theoretical and experimental topics, discussion sessions, and the 6th Young Researchers Workshop on Physics Challenges in the LHC Era’, which will take place on Monday, May 7th and on Thursday, May 10th. Students planning to participate in the School are strongly encouraged to apply to give a presentation of their research in the Workshop. The contributions will be published in Frascati Physics Series. A few fellowships covering the registration fee and/or accommodation are available for selected participants giving talks. The XIX LNF Spring School program will also feature the Spring School Colloquium The Origin of Life The Incredible Experiments of the Evolution in the Primordial Seas’, given by Marco Signore, Senior Researcher at Stazione Zoologica ‘Anton Dohrn’, Naples. The 2018 edition of the School consists of six sets of lectures, divided equally between theoretical and experimental topics, two discussion sessions, and the Spring School Colloquium on Science and Technology. Lecture topics: Dark Sectors: Theory Experimental Searches for Axions and Axion-Like Particles Experimental Searches for Dark Photons Top-quark and Higgs Physics at the LHC: Theory and Experiments Gravitational Waves: Theory, Detectors and Data Analysis Invited Lecturers: Maxim Pospelov (Victoria U. & Perimeter ...

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## Giorgio Salvini e i Laboratori Nazionali di Frascati

Inaugurazione dell’aula intitolata all’artefice della nascita dei Laboratori di Frascati. Il prossimo 24 aprile, il prof. Giorgi Salvini avrebbe compiuto 98 anni. I Laboratori Nazionali di Frascati, in occasione dell’inaugurazione dell’aula a lui intitolata, desiderano ricordare chi, a soli 34 anni, fu l’artefice della nascita dei Laboratori e tra i fondatori della ricerca in Fisica delle Particelle in Italia. E’ gradita conferma di partecipazione. REGISTRATI Info & Programma: https://agenda.infn.it/event/salvini2018

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## LNF Mini-Workshop Series: Muon production and beam interceptors

The purpose of this mini-workshop is to review some of the most advanced studies muon production and on the use high power beam interceptors in high energy physics and to discuss the possible applications to muon beam production from positron on target. Videoconference Room connection

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## K+ -> pi+ nunubar: first NA62 results

The decay K+->pi+nunu has a very precisely predicted branching ratio (BR) of less than 10^-10 and is one of the best candidates to reveal indirect effects of new physics at high mass scales. The NA62 experiment at CERN SPS is designed to measure BR(K+->pi+nn) with in-flight decays, a novel technique for this channel. NA62 took its first physics data in 2016, reaching sensitivity to the decay at the Standard Model BR. The experiment collected 10 times more statistics in 2017 and a similar amount of data is expected from the 2018 run. The preliminary result on K+->pi+nunu from the full 2016 data set will be presented and prospects for future improvements will be discussed.

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## Old experiments in a new environnement. Quantum Gravity effects from an experimental point of view

The General Relativity (GR) surely the most elegant theory in our possession, in spite of the recent measurement of Gravitational waves, has not yet been quantized and requires, in order to be compatible with cosmological observations, very unnatural hypotheses. Other theories came on age (MOND, Milne-Universe, etc.) but they do not seem to answer all the questions. On another side the very presence of negative energy solutions in Quantum Equations has always required an interpretation of the negative masses. What would be the scenario if we simply considered repulsive the gravitational interaction between "positive" masses and "negative" masses, between matter and antimatter? Various questions are proposed: A) A repulsive gravitational interaction is compatible with the elegant apparatus of the RG? B) Does a repulsive gravitational relationship generate at least one measurable phenomenon (contribution to CPV) in a viable experimental system? We propose an experimental test of the gravitational interaction with antimatter by measuring the branching fraction of the CP violating decay of KL in space or on the Moon. A 5 sigma discrimination may be obtained by collecting the KL produced by the cosmic proton flux within a few years. C) A repulsive gravitational relationship generates phenomena and suggests new modalities that can be the basis of an elegant alternative to "Dark Matter" and "Dark Energy".

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