Operational total space theory of principal 2-bundles I: Operational geometric framework

It is a classic result that the geometry of the total space of a principal bundle with reference to the action of the bundle's structure group is codified in the bundle's operation, a collection of derivations comprising the de Rham differential and the contraction and Lie derivatives of all vertical vector fields and obeying the six Cartan relations. In particular, connections and gauge transformations can be defined through the way they are acted upon by the operation's derivations. In this paper, the first of a series of two extending the ordinary theory, we construct an operational total space theory of strict principal 2--bundles with regard to the action of the structure strict 2--group. Expressing this latter via a crossed module (\mathsans{E},\mathsans{G}), the operation is based on the derived Lie group \mathfrak{e}[1]\rtimes\mathsans{G}. In the second paper, an original formulation of the theory of $2$--connections and $1$-- and $2$--gauge transformations based on the operational framework worked out here will be provided.Comment: The content of the original submission arXiv:1905.10057 has been extended and then split into two parts. This is part I. Improved results are presented. 59 pages, no figures, two appendice

Operational total space theory of principal 2-bundles II: 2-connections and 1- and 2-gauge transformations

The geometry of the total space of a principal bundle with regard to the action of the bundle's structure group is elegantly described by the bundle's operation, a collection of derivations consisting of the de Rham differential and the contraction and Lie derivatives of all vertical vector fields and satisfying the six Cartan relations. Connections and gauge transformations are defined by the way they behave under the action of the operation's derivations. In the first paper of a series of two extending the ordinary theory, we constructed an operational total space theory of strict principal 2--bundles with reference to the action of the structure strict 2--group. Expressing this latter through a crossed module (\mathsans{E},\mathsans{G}), the operation is based on the derived Lie group \mathfrak{e}[1]\rtimes\mathsans{G}. In this paper, the second of the series, an original formulation of the theory of $2$--connections and $1$-- and $2$--gauge transformations of principal $2$--bundles based on the operational framework is provided.Comment: The content of the original submission arXiv:1905.10057 has been extended and then split into two parts. This is part II. Improved results are presented. 68 pages, no figures, no appendice

Annual Report 2022

This report summarises the activities and main achievements of the CERN strategic R&D programme on technologies for future experiments during the year 202

Extension of the R&D Programme on Technologies for Future Experiments

we have conceived an extension of the R&D programme covering the period 2024 to 2028, i.e. again a 5-year period, however with 2024 as overlap year. This step was encouraged by the success of the current programme but also by the Europe-wide efforts to launch new Detector R&D collaborations in the framework of the ECFA Detector R&D Roadmap. We propose to continue our R&D programme with the main activities in essentially the same areas. All activities are fully aligned with the ECFA Roadmap and in most cases will be carried out under the umbrella of one of the new DRD collaborations. The program is a mix of natural continuations of the current activities and a couple of very innovative new developments, such as a radiation hard embedded FPGA implemented in an ASIC based on System-on-Chip technology. A special and urgent topic is the fabrication of Al-reinforced super-conducting cables. Such cables are a core ingredient of any new superconducting magnet such as BabyIAXO, PANDA, EIC, ALICE-3 etc. Production volumes are small and demands come in irregular intervals. Industry (world-wide) is no longer able and willing to fabricate such cables. The most effective approach (technically and financially) may be to re-invent the process at CERN, together with interested partners, and offer this service to the community

Annual Report 2023 and Phase-I Closeout

This report summarises the activities of the CERN strategic R&D programme on technologies for future experiments during the year 2023, and highlights the achievements of the programme during its first phase 2020-2023