NA64 Collaboration(Andreev, Y. M. et al), Molina Bueno, L., & Tuzi, M. (2025). Proof of principle for a light dark matter search with low-energy positron beams at NA64. J. High Energy Phys., 06(6), 256–39pp.
Abstract: Thermal light dark matter (LDM) with particle masses in the 1 MeV-1 GeV range could successfully explain the observed dark matter abundance as a relic from the primordial Universe. In this picture, a new feeble interaction acts as a “portal” between the Standard Model and LDM particles, allowing for the exploration of this paradigm at accelerator experiments. In the last years, the “missing energy” experiment NA64e at CERN SPS (Super Proton Synchrotron) has set world-leading constraints in the vector-mediated LDM parameter space, by exploiting a 100 GeV electron beam impinging on an electromagnetic calorimeter, acting as an active target. In this paper, we report a detailed description of the analysis of a preliminary measurement with a 70 GeV/c positron beam at NA64e, performed during summer 2023 with an accumulated statistics of 1.596 x 1010 positrons on target (hereafter referred to as e+OT). This data set was analyzed with the primary aim of evaluating the performance of the NA64e detector with a lower energy positron beam, towards the realization of the post-LS3 program. The analysis results, other than additionally probing unexplored regions in the LDM parameter space, provide valuable information towards the future NA64e positron campaign.
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DUNE Collaboration(Abud, A. A. et al), Amar Es-Sghir, H., Amedo, P., Antonova, M., Barenboim, G., Benitez Montiel, C., et al. (2025). The track-length extension fitting algorithm for energy measurement of interacting particles in liquid argon TPCs and its performance with ProtoDUNE-SP data. J. Instrum., 20(2), P02021–39pp.
Abstract: This paper introduces a novel track-length extension fitting algorithm for measuring the kinetic energies of inelastically interacting particles in liquid argon time projection chambers (LArTPCs). The algorithm finds the most probable offset in track length for a track-like object by comparing the measured ionization density as a function of position with a theoretical prediction of the energy loss as a function of the energy, including models of electron recombination and detector response. The algorithm can be used to measure the energies of particles that interact before they stop, such as charged pions that are absorbed by argon nuclei. The algorithm's energy measurement resolutions and fractional biases are presented as functions of particle kinetic energy and number of track hits using samples of stopping secondary charged pions in data collected by the ProtoDUNE-SP detector, and also in a detailed simulation. Additional studies describe the impact of the dE/dx model on energy measurement performance. The method described in this paper to characterize the energy measurement performance can be repeated in any LArTPC experiment using stopping secondary charged pions.
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NA64 Collaboration(Andreev, Y. M. et al), Molina Bueno, L., & Tuzi, M. (2024). Shedding light on dark sectors with high-energy muons at the NA64 experiment at the CERN SPS. Phys. Rev. D, 110(11), 112015–23pp.
Abstract: A search for dark sectors is performed using the unique M2 beam line at the CERN Super Proton Synchrotron. New particles (X) could be produced in the bremsstrahlung-like reaction of high-energy 160 GeV positively charged muons impinging on an active target, μN -> μNX, followed by their decays, X -> invisible. The experimental signature would be a scattered single muon from the target, with about less than half of its initial energy and no activity in the subdetectors located downstream from the interaction point. The full sample of the 2022 run is analyzed through the missing-energy/momentum channel, with total statistics of (1.98 +/- 0.02) x 10(10) muons on target. We demonstrate that various muonphilic scenarios involving different types of mediators, such as scalar or vector particles, can be probed simultaneously with such a technique. For the vector case, besides a L-mu – L-tau Z' vector boson, we also consider an invisibly decaying dark photon (A' -> invisible). This search is complementary to NA64 running with electrons and positrons, thus opening the possibility to expand the exploration of the thermal light dark matter parameter space by combining the results obtained with the three beams.
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DUNE Collaboration(Abud, A. A. et al), Amar, H., Amedo, P., Antonova, M., Barenboim, G., Benitez Montiel, C., et al. (2024). DUNE Phase II: scientific opportunities, detector concepts, technological solutions. J. Instrum., 19(12), P12005–91pp.
Abstract: The international collaboration designing and constructing the Deep Underground Neutrino Experiment (DUNE) at the Long-Baseline Neutrino Facility (LBNF) has developed a two-phase strategy toward the implementation of this leading-edge, large-scale science project. The 2023 report of the US Particle Physics Project Prioritization Panel (P5) reaffirmed this vision and strongly endorsed DUNE Phase I and Phase II, as did the European Strategy for Particle Physics. While the construction of the DUNE Phase I is well underway, this White Paper focuses on DUNE Phase II planning. DUNE Phase-II consists of a third and fourth far detector (FD) module, an upgraded near detector complex, and an enhanced 2.1 MW beam. The fourth FD module is conceived as a “Module of Opportunity”, aimed at expanding the physics opportunities, in addition to supporting the core DUNE science program, with more advanced technologies. This document highlights the increased science opportunities offered by the DUNE Phase II near and far detectors, including long-baseline neutrino oscillation physics, neutrino astrophysics, and physics beyond the standard model. It describes the DUNE Phase II near and far detector technologies and detector design concepts that are currently under consideration. A summary of key R&D goals and prototyping phases needed to realize the Phase II detector technical designs is also provided. DUNE's Phase II detectors, along with the increased beam power, will complete the full scope of DUNE, enabling a multi-decadal program of groundbreaking science with neutrinos.
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DUNE Collaboration(Abud, A. A. et al), Amar Es-Sghir, H., Amedo, P., Antonova, M., Barenboim, G., Benitez Montiel, C., et al. (2024). First measurement of the total inelastic cross section of positively charged kaons on argon at energies between 5.0 and 7.5 GeV. Phys. Rev. D, 110(9), 092011–22pp.
Abstract: ProtoDUNE Single-Phase (ProtoDUNE-SP) is a 770-ton liquid argon time projection chamber that operated in a hadron test beam at the CERN Neutrino Platform in 2018. We present a measurement of the total inelastic cross section of charged kaons on argon as a function of kaon energy using 6 and 7 GeV/c beam momentum settings. The flux-weighted average of the extracted inelastic cross section at each beam momentum setting was measured to be 380 +/- 26 mbarns for the 6 GeV/c setting and 379 +/- 35 mbarns for the 7 GeV/c setting.
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