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Analytical and Numerical Study of Superconducting Dipole and Quadrupole Performance Limits for a Muon Collider
No full textIn accordance with the guidelines set forth in the Updated European Strategy for Particle Physics, the International Muon Collider Collaboration has been initiated to assess the feasibility of a Muon Collider facility with a center-of-mass energy of 10 TeV. The primary challenges stem from the brief muon lifetime at rest, which is limited to 2.2 µs. Addressing this demanding condition necessitates the incorporation of advanced technologies in magnets, RF systems, targets, shielding, and cooling. To minimize collimated neutrino beams resulting from muon decay and reduce the impact of radiation background around the facility, the straight sections in the collider ring must be minimized. Achieving this goal involves integrating beam optics quadrupoles with bending dipoles featuring a high magnetic field (10 T) and gradient (100 T/m) within a large aperture (140 mm). These stringent constraints require cutting-edge technologies in material selection, mechanical layout, quench protection, shielding, and cooling. This contribution explores the performance limits of potential candidate materials for such magnets, specifically LTS (Low-Temperature Superconductors) NbSn and (High-Temperature Superconductors) ReBCO, regarding the maximum field, mechanical stress, and stored energy. We present an original approach that allows us to explore the achievable phase space of parameters using both analytical expressions and the FEM software ANSYS, handled by Python code. Using this approach, we will show the obtained results for dipoles and quadrupoles
Low dose gamma irradiation study of ATLAS ITk MD8 diodes
No full textSilicon strip detectors developed for the Inner Tracker (ITk) of the ATLAS experiment will operate in a harsh radiation environment of the HL-LHC accelerator. The ITk is thus designed to endure a total fluence of 1.6 × 1015 1 MeV neq/cm2 and a total ionizing dose (TID) of 66 Mrad in the strip detector region. A radiation-hard +-in- technology is implemented in the ITk strip sensors. To achieve the required radiation hardness, extensive irradiation studies were conducted during sensor development, primarily performed up to the maximal expected total fluence and TID to ensure a full functionality of the detector at its end-of-life. These studies included irradiations of sensors with various particle types and energies, including the 60Co -rays. Our previous results obtained for -irradiated diodes and strip sensors indicate a linear increase of bulk current with TID, while a surface current saturates at the lowest TID levels checked (66 Mrad), preventing a determination of the exact TID for which the observed saturation occurs. This work presents the results coming from irradiations by 60Co -rays to multiple low TIDs, ranging from 0.5 to 100 krad. The detailed study of total, bulk, and surface currents of diodes explores an unknown dependence of surface current on the TID, annealing, and temperature. Additionally, the effect of the -stop implant between the bias and the guard ring of measured samples is shown. The observations are relevant for the initial operations of the new ATLAS tracker
Proposal of the KOTO II experiment
No full textThe KOTO II experiment is proposed to measure the branching ratio of the decay at J-PARC. With a beamline to extract long-lived neutral kaons at 5 degrees from a production target, the single event sensitivity of the decay is , which is much smaller than the Standard Model prediction . This allows searches for new physics beyond the Standard Model and the first discovery of the decay with a significance exceeding . As the only experiment proposed in the world dedicated to rare kaon decays, KOTO II will be indispensable in the quest for a complete understanding of flavor dynamics in the quark sector. Moreover, by combining efforts from the kaon community worldwide, we plan to develop the KOTO II detector further and expand the physics reach of the experiment to include measurements of the branching ratio of the decays, studies of other decays, and searches for dark photons, axions, and axion-like particles. KOTO II will therefore obtain a comprehensive understanding of decays, providing further constraints on new physics scenarios with existing results
Triplet assembly and certification of the new generation of RPC for the ATLAS phase-2 upgrade at Max Planck Institute
No full textA new generation of Resistive Plate Chambers have been developed for the ATLAS phase-2 upgrade in sight of the High-Luminosity phase of the Large Hadron Collider. These RPCs consist of three independent 1 mm gas gaps(singlets) equipped with a newly low-threshold Front-End electronics, assembled in the same mechanical structure (triplet). During 2024 the production of the phase-2 RPCs started and the detectors will undergo (2024-2025) a certification test before the installation in the ATLAS cavern. The triplet assembly and the certification with cosmic rays of the BIS-type detectors is performed at the Max-Planck-Institute for Physics (MPI) in Munich. The architecture of the cosmic rays test stand has been built at MPI and has been studied in order to provide an efficient and robust structure to ensure an excellent quality control and study precisely the whole RPC performance needed to certify the detectors for the ATLAS experiment. In this presentation the assembly procedure, the architecture of the test stand and the certification protocols will be presented along with the validation tests to characterize the RPC performance.A new generation of Resistive Plate Chambers has been developed for the ATLAS phase-2 upgrade in view of the High-Luminosity phase of the Large Hadron Collider. These RPCs consist of three independent 1 mm gas gaps(singlets) equipped with a newly developed low-threshold Front-End electronics, assembled in the same mechanical structure (triplet). During 2024, the production of the phase-2 RPCs started and the detectors will undergo a certification test (between 2024 and 2025) before the installation in the ATLAS cavern. The triplet assembly and the certification with cosmic rays of the BIS-type detectors is performed at the Max-Planck-Institute for Physics (MPI) in Munich. The architecture of the cosmic rays test stand has been built at MPI and has been studied in order to provide an efficient and robust structure, to ensure an excellent quality control and study precisely the whole RPC performance needed to certify the detectors for the ATLAS experiment. In this presentation, the assembly procedure, the architecture of the test stand and the certification protocols will be presented along with the validation tests to characterize the RPC performance.A new generation of Resistive Plate Chambers have been developed for the ATLAS phase-2 upgrade in sight of the High-Luminosity phase of the Large Hadron Collider. These RPCs consist of three independent 1 mm gas gaps(singlets) equipped with a newly low-threshold Front-End electronics, assembled in the same mechanical structure (triplet). During 2024 the production of the phase-2 RPCs started and the detectors will undergo (2024-2025) a certification test before the installation in the ATLAS cavern. The triplet assembly and the certification with cosmic rays of the BIS-type detectors is performed at the Max-Planck-Institute for Physics (MPI) in Munich. The architecture of the cosmic rays test stand has been built at MPI and has been studied in order to provide an efficient and robust structure to ensure an excellent quality control and study precisely the whole RPC performance needed to certify the detectors for the ATLAS experiment. In this presentation the assembly procedure, the architecture of the test stand and the certification protocols will be presented along with the validation tests to characterize the RPC performance
On quivers, spectral networks and black holes
No full textIt was recently found that connection coefficients of the Heun equation can be derived in closed form using crossing symmetry in two-dimensional Liouville theory via the Nekrasov-Shatashvili functions. In this work, we systematize this approach to second-order linear ODEs of Fuchsian type, which arise in the description of N = 2, four-dimensional quiver gauge theories. After presenting the general procedure, we focus on the specific case of Fuchsian equations with five regular singularities and present some applications to black hole perturbation theory. First, we consider a massive scalar perturbation of the Schwarzschild black hole in AdS7. Next, we analyze vector type perturbations of the Reissner-Nordström-AdS5 black hole. We also discuss the implications of our results in the context of the AdS/CFT correspondence and present explicit results in the large spin limit, where we make connection with the light-cone bootstrap. Furthermore, using the spectral network technology, we identify the region of the moduli space in Seiberg-Witten theory that is relevant for the study of black hole quasinormal modes. Our results suggest that, in some cases, this region corresponds to the strong-coupling regime, highlighting the potential applicability of the conformal GMN TBA framework to address scenarios where the gravitational dictionary implies that the instanton counting parameters are not parametrically small
Uncertainty: CERN Art and Science Summit, an event curated by Arts at CERN
No full textThe CERN Art and Science Summit highlights the achievement of CERN’s forward-thinking approach to arts and creativity. Following the inaugural Summit in 2024, the second edition brought together a selected group of guests, including artists who participated in Arts at CERN’s programmes. This year’s theme, Uncertainty, aligns with UNESCO’s declaration of 2025 as the International Year of Quantum Science and Technology. This initiative celebrates the impacts of quantum science, marking a century since a group of scientists laid the foundations of quantum physics in Europe. Quantum physics describes nature in all its extraordinary complexity, and artists have assumed an important role in this process. Over recent decades, it has gained a significant impact on contemporary culture. It’s well known that it has affected the tropes of art, philosophy, film and literature. This cultural impact reflects society’s growing interest in fundamental research and physics. Within this thematic framework, guest speakers and attendees will be invited to explore the world of physics, the ‘quantum moment’, and its vast influence on culture. The CERN Art and Science Summit is curated annually by the Arts at CERN team. As a renowned platform for the intersection of arts and sciences, Arts at CERN fosters engagement and discussion between artists and scientists