Feebly-Interacting Particles:FIPs 2020 Workshop Report

With the establishment and maturation of the experimental programs searching for new physics with sizeable couplings at the LHC, there is an increasing interest in the broader particle and astrophysics community for exploring the physics of light and feebly-interacting particles as a paradigm complementary to a New Physics sector at the TeV scale and beyond. FIPs 2020 has been the first workshop fully dedicated to the physics of feebly-interacting particles and was held virtually from 31 August to 4 September 2020. The workshop has gathered together experts from collider, beam dump, fixed target experiments, as well as from astrophysics, axions/ALPs searches, current/future neutrino experiments, and dark matter direct detection communities to discuss progress in experimental searches and underlying theory models for FIPs physics, and to enhance the cross-fertilisation across different fields. FIPs 2020 has been complemented by the topical workshop "Physics Beyond Colliders meets theory", held at CERN from 7 June to 9 June 2020. This document presents the summary of the talks presented at the workshops and the outcome of the subsequent discussions held immediately after. It aims to provide a clear picture of this blooming field and proposes a few recommendations for the next round of experimental results.Comment: 240 pages, 71 figure

The present and future status of heavy neutral leptons

The existence of nonzero neutrino masses points to the likely existence of multiple Standard Model neutral fermions. When such states are heavy enough that they cannot be produced in oscillations, they are referred to as heavy neutral leptons (HNLs). In this white paper, we discuss the present experimental status of HNLs including colliders, beta decay, accelerators, as well as astrophysical and cosmological impacts. We discuss the importance of continuing to search for HNLs, and its potential impact on our understanding of key fundamental questions, and additionally we outline the future prospects for next-generation future experiments or upcoming accelerator run scenarios.Peer reviewe

Development of Physical Protection Regulations for Rosatom State Corporation Sites under the U.S.-Russian MPC&A Program

This paper describes issues related to upgrading the physical protection regulatory basis for Rosatom State Corporation sites. It is underlined that most of the regulatory and methodological documents for this subject area have been developed under the U.S.-Russian MPC&A Program. According to the joint management plan developed and agreed upon by the parties in 2005, nearly 50 physical protection documents were identified to be developed, approved and implemented at Rosatom sites by 2012. It is also noted that, on the whole, the plans have been fulfilled

Development of Physical Protection Regulations for Rosatom State Corporation Sites under the U.S.-Russian MPC&A Program

This paper describes issues related to upgrading the physical protection regulatory basis for Rosatom State Corporation sites. It is underlined that most of the regulatory and methodological documents for this subject area have been developed under the U.S.-Russian MPC&A Program. According to the joint management plan developed and agreed upon by the parties in 2005, nearly 50 physical protection documents were identified to be developed, approved and implemented at Rosatom sites by 2012. It is also noted that, on the whole, the plans have been fulfilled

Background and muon counting rates in underground muon measurements with a plastic scintillator counter based on a wavelength shifting fibre and a multi-pixel avalanche photodiode readout

In this short note we present results of background measurements carried out with polystyrene based cast plastic 12.0×12.0×3.0 cm3 size scintillator counter with a wavelength shifting fibre and a multi-pixel Geiger mode avalanche photodiode readout in the Baksan underground laboratory at a depth of 200 metres of water equivalent. The total counting rate of the scintillator counter measured at this depth and at a threshold corresponding to ∼0.37 of a minimum ionizing particle is approximately 1.3 Hz.peerReviewe