2022
Physics analyses at the LHC. — A search for supersymmetry in proton-proton collisions at 13 TeV center of mass energy motivated by the gauge mediated supersymmetry breaking model in which low-mass gravitinos are assumed to be the lightest supersymmetric particles (LSP) and neutralinos are the nex-to-LSPs is being developed observing final states with photon, b-tagged jets and missing transverse momentum. In the considered simplified models, the neutralinos are either directly produced via electroweak processes or are the decay products of strongly produced gluino pairs. The expected lower exclusion limit in the electroweak model is 1.2 TeV for the neutralino, and in the strong process model, 1.8 – 2.2 TeV for the gluino. The analysis methods are being finalized, in collaboration with ELTE colleagues, for the improved reconstructed Run 2 data and simulation (so called Ultra Legacy datasets [1])
The inclusive search for supersymmetry using razor variables and boosted object identification in zero and one lepton final states are also being updated using the entire Run 2 data. We have contributed to this analysis in 2022 by calculating the electron and muon scale factors that are used to correct for the object reconstruction and cut discrepancies between simulation and collision data.
The searches for new physics in the Run 2 data are near completion, and a significant improvement in sensitivity is only foreseen towards the end of Run 3. While we are preparing to incorporate new data to be measured between 2022 and 2025 into these searches, we have started to set up a precision measurement of the Standard Model in order to further exploit the already available data. We have started to study the Z boson production with two heavy flavor jets, processes that are of interest both as major, often irreducible, backgrounds in the studies of the Higgs boson and as subjects of relatively incomplete studies in the hadronic collider experiments.
Detector operation and construction. — With the start of Run 3 in 2022, we have carried out initial calibrations and performance studies of the pixel detector. High voltage bias scans were performed 14 times and the evolution of the charge collection efficiency as function of the production depth were measured throughout the year in order to monitor the evolution of the silicon bulk due to radiation damage. The pixel detector will suffer a large radiation damage, to the greatest extent in layer 1 (the innermost layer), towards the end of Run 3 and the clusters are expected to be broken. This will lead to a loss in tracking efficiency and performance. To repair these broken clusters, an algorithm has been developed and tested on MC simulation.
The production of the CMS Phase-2 hybrid electronics started at the end of 2022, the testing and the module assembly will start in 2023. The preparation of the infrastructure and the training of the team for the visual inspection of the electronics continued during 2022. We have improved the ESD protection of the clean room and finalized the setup of the workstations, where about 20000 circuits will be inspected with stereo-microscopes in the next three years. We have made several developments concerning the large area optical scanner, which will be also used during the optical testing of the hybrids. We also contributed in the testing of the prototypes and wrote an Inspection Manual.
SuShi septum for the Future Circular Collider (FCC). — In collaboration with CERN, the FCC SuShi septum prototype magnet's winding has been completed (Fig. 1, 2). A method has been developed to impregnate CCT magnets with wax, coping with its ~15% volumentric upon solidification (Fig. 3)
Fig. 1. Winding of the SuShi septum magnet
Fig. 2. Winding of the SuShi septum magnet
Hadron therapy. — The group is participating in the HITRI+ project to develop a compact superconducting synchrotron for proton and carton ion treatment of tumors. A new algorithm for optimizing the field quality of curved CCT magnets have been developed [2].
Test winding of a straight CCT former with 2x8 polyester-insulated twisted ropes (each containing 7 superconducting strands) has been carried out at Wigner RCP with the participation of colleagues from INFN Milano, and Ciemat. (Fig. 4). The developed method of wax impregnation was demonstrated to work in this configuration as well.
Fig. 3. Demonstration of the wax impregnation method. A single CCT layer impregnated with wax, without voids.
Fig. 4. Test winding of a straight CCT former for the HITRI+ project.