Ariel [1] is the M4 mission of the ESA's Cosmic Vision Program 2015-2025, whose aim is to characterize by low-resolution transit spectroscopy the atmospheres of over one thousand warm and hot exoplanets orbiting nearby stars. The operational orbit of the spacecraft is baselined as a large amplitude halo orbit around the Sun-Earth L2 Lagrangian point, as it offers the possibility of long uninterrupted observations in a fairly stable radiative and thermo-mechanical environment. A direct escape injection with a single passage through the Earth radiation belts and no eclipses is foreseen. The space environment around Earth and L2 presents significant design challenges to all spacecraft, including the effects of interactions with Sun radiation and charged particles owning to the surrounding plasma environment, potentially leading to dielectrics charging and unwanted electrostatic discharge (ESD) phenomena endangering the Payload operations and its data integrity. Here, we present some preliminary simulations and analyses about the Ariel Payload dielectrics and semiconductors charging along the transfer orbit from launch to L2 included.

We report high-precision measurements of the Deeply Virtual Compton Scattering (DVCS) cross section at high values of the Bjorken variable x_B. DVCS is sensitive to the Generalized Parton Distributions of the nucleon, which provide a three-dimensional description of its internal constituents. Using the exact analytic expression of the DVCS cross section for all possible polarization states of the initial and final electron and nucleon, and final state photon, we present the first experimental extraction of all four helicity-conserving Compton Form Factors (CFFs) of the nucleon as a function of x_B, while systematically including helicity flip amplitudes. In particular, the high accuracy of the present data demonstrates sensitivity to some very poorly known CFFs.

CSES-01 (China Seismo-Electromagnetic Satellite) is a space mission dedicated to the study of the ionospheric environment, searching for disturbances that can be correlated to seismic activity. For this reason, the satellite is equipped with several instruments to monitor various physical parameters including the Earth's electric and magnetic field, ionospheric plasma principal parameters (i.e. density, temperature, and ions composition) and high energy particle flux fluctuations. The High Energy Particle Detector (HEPD), built by the Italian CSES-Limadou collaboration, is designed to detect mostly electrons in the energy range between 3 MeV and 100 MeV and protons in the energy range between 30 MeV and 300 MeV. The detector is composed of a tracking system, a segmented layer of plastic scintillator (used for the trigger), a range calorimeter and a veto system. After CSES-01 launch (February 2, 2018), the apparatus underwent the commissioning phase where its configuration was adjusted in order to guarantee optimal operational conditions in the space environment. Now the satellite is in stable data-taking mode. In this work a description of the HEPD detector will be reported, focusing on the results of the electron and proton test beam calibrations. In addition, a particular relevance will be given to the presentation of the HEPD in-flight performance, such as its good capability in particle identification. The high statistic collected by HEPD, thanks to its large acceptance window, makes it perfectly suitable for the investigation of fluctuations in the charged particle fluxes.

CSES (China Seismo-Electromagnetic Satellite) is a Chinese-Italian scientific space mission dedicated to monitor the variations of the main parameters of the topside ionosphere (electric and magnetic fields, plasma parameters, charge particle fluxes) caused by either natural emitters - especially earthquakes - or artificial ones. The CSES satellite was successfully launched from the Jiuquan Satellite Launch Center located in the west of Inner Mongolia on February 2nd, 2018, and it is now orbiting under nominal conditions. The expected mission lifetime amounts to 5 years. CSES is the first element of a multi-satellite monitoring system; several satellites are scheduled for the next few years. The High-Energy Particle Detector (HEPD) is the main contribution of the Italian collaboration to the mission. It was designed and built in order to detect electrons in the energy range between 3 and 100 MeV, protons between 30 and 200 MeV, and light nuclei in the MeV energy window. The electronics of the detector was designed following stringent requirements on mechanical and thermal stability, power consumption, radiation hardness and double redundancy. The system successfully went through the space qualification tests. In this paper, we describe the HEPD electronics, the space qualification tests performed before launch, and the in-flight performance of the detector.

We report measurements of the exclusive neutral pion electroproduction cross section off protons at large values of x_{B} (0.36, 0.48, and 0.60) and Q^{2} (3.1 to 8.4  GeV^{2}) obtained from Jefferson Lab Hall A experiment E12-06-014. The corresponding structure functions dσ_{T}/dt+εdσ_{L}/dt, dσ_{TT}/dt, dσ_{LT}/dt, and dσ_{LT^{'}}/dt are extracted as a function of the proton momentum transfer t-t_{min}. The results suggest the amplitude for transversely polarized virtual photons continues to dominate the cross section throughout this kinematic range. The data are well described by calculations based on transversity generalized parton distributions coupled to a helicity flip distribution amplitude of the pion, thus providing a unique way to probe the structure of the nucleon.

CSES (China Seismo-Electromagnetic Satellite) is a Chinese-Italian space mission dedicated to monitoring of variations of the electromagnetic field and waves, plasma parameters, and particle fluxes induced by natural sources and artificial emitters in the near-Earth space. The satellite was launched from the Jiuquan Satellite Launch Center in the Gobi desert (Inner Mongolia, China) on 2, 2018. The expected mission lifetime amounts to 5 years.

The High-energy Particle Detector (HEPD) on board the China Seismo-Electromagnetic Satellite (CSES-01)—launched on 2018 February 2—is a light and compact payload suitable for measuring electrons (3–100 MeV), protons (30–250 MeV), and light nuclei (up to a few hundreds of MeV). The Sun-synchronous orbit and large acceptance allow HEPD to measure cosmic-ray particles near the ±65° latitude limit for a fair amount of time per day. In this work, three semiannual galactic hydrogen energy spectra between ∼40 and 250 MeV are presented, including a comparison with theoretical spectra from HelMod, a 2D Monte Carlo model developed to simulate the solar modulation of cosmic rays throughout the heliosphere. To our knowledge, these are the first hydrogen energy spectra below 250 MeV measured at 1 au between 2018 and 2020.

This document complements and completes what was submitted last year to PAC45 as an update to the proposal PR12-16-001 "Dark matter search in a Beam-Dump eXperiment (BDX)" at Jefferson Lab submitted to JLab-PAC44 in 2016. Following the suggestions contained in the PAC45 report, in coordination with the lab, we ran a test to assess the beam-related backgrounds and validate the simulation framework used to design the BDX experiment. Using a common Monte Carlo framework for the test and the proposed experiment, we optimized the selection cuts to maximize the reach considering simultaneously the signal, cosmic-ray background (assessed in Catania test with BDX-Proto) and beam-related backgrounds (irreducible NC and CC neutrino interactions as determined by simulation). Our results confirmed what was presented in the original proposal: with 285 days of a parasitic run at 65 $\mu$A (corresponding to $10^{22}$ EOT) the BDX experiment will lower the exclusion limits in the case of no signal by one to two orders of magnitude in the parameter space of dark-matter coupling versus mass.

CSES-01 (China Seismo-Electromagnetic Satellite) is a mission developed by CNSA (Chinese National Space Administration) and ASI (Italian Space Agency) to investigate the near-Earth electromagnetic, plasma and particle environment, focusing on the disturbances of the ionosphere-magnetosphere transition region. In this framework, the Italian High Energy Particle Detector (HEPD) on board CSES-01, is an advanced detector based on a tower of scintillators and a silicon tracker that provide good energy resolution as well as a wide angular acceptance for electrons of 3-100 MeV, protons of 30-200 MeV and light nuclei (up to Oxygen). The very good capabilities in both detection and discrimination of particles make the detector well suited for space-weather purposes; indeed HEPD is able to continuously monitor the magnetospheric environment with high precision and stability in time. Turbulent conditions in the near-Earth environment translate into modification of particles and magnetic/electric measurements at different time-scales. In this work, the data-analysis techniques and some preliminary results concerning the study of different proton populations encountered along CSES-01 orbit (galactic cosmic rays, re-entrant albedo etc.) are presented.

List of contributions from the Cherenkov Telescope Array Consortium presented at the 35th International Cosmic Ray Conference, July 12-20 2017, Busan, Korea.

MeV-GeV dark matter (DM) is theoretically well motivated but remarkably unexplored. This proposal presents the MeV-GeV DM discovery potential for a $\sim$1 m$^3$ segmented CsI(Tl) scintillator detector placed downstream of the Hall A beam-dump at Jefferson Lab, receiving up to 10$^{22}$ electrons-on-target (EOT) in 285 days. This experiment (Beam-Dump eXperiment or BDX) would be sensitive to elastic DM-electron and to inelastic DM scattering at the level of 10 counts per year, reaching the limit of the neutrino irreducible background. The distinct signature of a DM interaction will be an electromagnetic shower of few hundreds of MeV, together with a reduced activity in the surrounding active veto counters. A detailed description of the DM particle $\chi$ production in the dump and subsequent interaction in the detector has been performed by means of Monte Carlo simulations. Different approaches have been used to evaluate the expected backgrounds: the cosmogenic background has been extrapolated from the results obtained with a prototype detector running at INFN-LNS (Italy), while the beam-related background has been evaluated by GEANT4 Monte Carlo simulations. The proposed experiment will be sensitive to large regions of DM parameter space, exceeding the discovery potential of existing and planned experiments in the MeV-GeV DM mass range by up to two orders of magnitude.

This document is an update to the proposal PR12-16-001 Dark matter search in a Beam-Dump eXperiment (BDX) at Jefferson Lab submitted to JLab-PAC44 in 2016 reporting progress in addressing questions raised regarding the beam-on backgrounds. The concerns are addressed by adopting a new simulation tool, FLUKA, and planning measurements of muon fluxes from the dump with its existing shielding around the dump. First, we have implemented the detailed BDX experimental geometry into a FLUKA simulation, in consultation with experts from the JLab Radiation Control Group. The FLUKA simulation has been compared directly to our GEANT4 simulations and shown to agree in regions of validity. The FLUKA interaction package, with a tuned set of biasing weights, is naturally able to generate reliable particle distributions with very small probabilities and therefore predict rates at the detector location beyond the planned shielding around the beam dump. Second, we have developed a plan to conduct measurements of the muon ux from the Hall-A dump in its current configuration to validate our simulations.

The Cherenkov Telescope Array is a project that aims to exploring the highest energy region of electromagnetic spectrum. Two arrays, one for each hemisphere, will cover the full sky in a range from few tens of GeV to hundreds of TeV improving the sensitivity and angular resolution of the present operating arrays. A prototype of the Large Size Telescope (LST) for the study of gamma ray astronomy above some tens of GeV will be installed at the Canary Island of La Palma in 2016. The LST camera, made by an array of photomultipliers (PMTs), requires an accurate and systematic calibration over a wide dynamic range. In this contribution, we present an optical calibration system made by a 355 nm wavelength laser with 400 ps pulse width, 1 muJ output energy, up to 4k Hz repetition rate and a set of neutral density filters to obtain a wide range of photon intensities, up to 1000 photoelectrons/PMT, to be sent to the camera plane 28 m away. The number of photons after the diffuser of the calibration box, located in the center of the reflective plane, is monitored by a photodiode. The stability of the laser and the ambient parameters inside this calibration box are checked by a multi-task processor and a trigger signal is sent to the camera data acquisition system. The box frame is designed with special attention to obtain a robust device with stable optical and mechanical features.

The physics case and an experimental overview of the MOLLER (Measurement Of a Lepton Lepton Electroweak Reaction) experiment at the 12 GeV upgraded Jefferson Lab are presented. A highlight of the Fundamental Symmetries subfield of the 2007 NSAC Long Range Plan was the SLAC E158 measurement of the parity-violating asymmetry A_PV in polarized electron-electron (Møller) scattering. The proposed MOLLER experiment will improve on this result by a factor of five, yielding the most precise measurement of the weak mixing angle at low or high energy anticipated over the next decade. This new result would be sensitive to the interference of the electromagnetic amplitude with new neutral current amplitudes as weak as ∼ 10^-3· G_F from as yet undiscovered dynamics beyond the Standard Model. The resulting discovery reach is unmatched by any proposed experiment measuring a flavor- and CP-conserving process over the next decade, and yields a unique window to new physics at MeV and multi-TeV scales, complementary to direct searches at high energy colliders such as the Large Hadron Collider (LHC). The experiment takes advantage of the unique opportunity provided by the upgraded electron beam energy, luminosity, and stability at Jefferson Laboratory and the extensive experience accumulated in the community after a round of recent successfully completed parity-violating electron scattering experiments

We developed and tested a new charged particle tracking system, able to operate in high luminosity experiments, which will be installed at Jefferson Laboratory HallA (VA, USA) for optimally exploit the new 12GeV energy electron beam available at the end of 2013. The tracker is made of six GEM (Gas Electron Multiplier) large chambers and two 10×20cm2 planes of SIlicon microstrip Detectors (SIDs). Each GEM chamber is composed by three 40×50cm2 GEM modules, with two-dimensional strip readout, with expected spatial resolution of about 70μm. The same dedicated acquisition system will be used for both detectors (GEM & SID) for a grand total of more than 50,000 channels. The readout electronics is divided into two parts: the front-end cards (based on the existing APV25 chip), hosted on the detectors periphery and the digitizer, a multi purpose VME-64x/VXS board located far from the high radiation environment. The very same electronics has been adopted by the Olympus experiment (DESY, Hamburg, D) to read out the six GEM chambers of its luminosity monitor. The developed detectors and electronics are now ready for the production, which will last for the next 2 years.

A new hybrid silicon μstrip and large area GEM (Gas Electron Multiplier) tracker is under development for the upcoming high luminosity (up to 1039 /s/cm2) experiments at the Hall-A of the JLab 12 GeV electron beam facility. The system consists of 2 small 10×20 cm2 silicon planes placed near the scattering chamber and 18 40×50 cm2 GEM modules that form larger chambers with variable active area depending on the experimental needs. Rather general purpose readout electronics has been designed for both detectors and can be adopted in other equipment. It consists of two active components: front-end cards, directly connected to the detector channels and a multi-purpose digitizer board (MPD). The front-end is based on existing 128 channels APV25-S1 chip developed in the framework of LHC experiments. The MPD handles 16 front-end cards (for a total of 2048 channels) and can be used in VME environments (also VME64x or VXS). It also provides: optical, Ethernet, USB. These resources permit to use MPD cards in different frameworks, ranging from small bench-top to large on-detector distributed systems. The GEM project is part of the CERN/RD51 collaboration activities. The system has been beam tested in late 2010 and 2011, some results are presented here.