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Tani, A., Ikeno, N., Jido, D., Nagahiro, H., Fujioka, H., Itahashi, K., et al. (2021). Structure of double pionic atoms. Prog. Theor. Exp. Phys., 2021(3), 033D02–16pp.
Abstract: We study theoretically the structure of double pionic atoms, in which two negatively charged pions (pi(-)) are bound in the atomic orbits. The double pionic atom is considered to be an interesting system from the point of view of the multi-bosonic systems. In addition, it could be possible to deduce valuable information on the isospin I = 2 pi pi interaction and the pionnucleus strong interaction. In this paper, we take into account the pi pi strong and electromagnetic interactions, and evaluate the effects on the binding energies by perturbation theory for the double pionic atoms in heavy nuclei. We investigate several combinations of two pionic states and find that the order of magnitude of the energy shifts due to the pi pi interaction is around 10 keV for the strong interaction and around 100 keV for the electromagnetic interaction for the ground states.
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T2K Collaboration(Abe, K. et al), Antonova, M., Cervera-Villanueva, A., & Novella, P. (2021). Measurements of (nu)over-bar(mu) and (nu)over-bar(mu) + nu(mu) charged-current cross-sections without detected pions or protons on water and hydrocarbon at a mean anti-neutrino energy of 0.86 GeV. Prog. Theor. Exp. Phys., 2021(4), 043C01–28pp.
Abstract: We report measurements of the flux-integrated (nu) over bar (mu) and (nu) over bar (mu) + nu(mu) charged-current cross -sections on water and hydrocarbon targets using the T2K anti-neutrino beam with a mean beam energy of 0.86 GeV. The signal is defined as the (anti -)neutrino charged-current interaction with one induced mu(+/-) and no detected charged pion or proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton Module. The phase space of muons is restricted to the high-detection efficiency region, p(mu) > 400 MeV/c and theta(mu) < 30 degrees, in the laboratory frame. An absence of pions and protons in the detectable phase spaces of p(pi) > 200 MeV/c, theta(pi) < 70 degrees and p(p) > 600 MeV/c, theta(p) < 70 degrees is required. In this paper, both the <(nu)over bar>(mu), cross-sections and (nu) over bar (mu) + nu(mu), cross-sections on water and hydrocarbon targets and their ratios are provided by using the D'Agostini unfolding method. The results of the integrated (nu) over bar (mu), cross-section measurements over this phase space are sigma(H2O) = (1.082 +/- 0.068(stat.)(+0.145)(-0.128)(syst.)) x 10(-39) cm(2)/nucleon, sigma(CH) = (1.096 +/- 0.054 (stat.)(+0.132)(-0.117)(syst.)) x 10(-39) cm(2) /nucleon, and sigma(H2O)/sigma(CH) = 0.987 +/- 0.078 (stat.)(+0.093)(-0.090)(syst.). The (nu) over bar (mu), + nu(mu), cross-section is sigma(H2O) = (1.155 +/- 0.064(stat.)(+0.148)(-0.129)(syst.)) x 10(-39) cm(2)/nucleon, sigma(CH) = (1.159 +/- 0.049(stat.)(+0.129)(-0.115)(syst.)) x 10(-39) cm(2)/nucleon, and sigma(H2O)/sigma(CH) = 0.996 +/- 0.069(stat.)(+0.083)(-0.078)(syst.).
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Particle Data Group(Zyla, P. A. et al), Hernandez-Rey, J. J., & Pich, A. (2020). Review of Particle Physics. Prog. Theor. Exp. Phys., 2020(8), 083C01–2093pp.
Abstract: The Review summarizes much of particle physics and cosmology. Using data from previous editions, plus 3,324 new measurements from 878 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Among the 120 reviews are many that are new or heavily revised, including a new review on High Energy Soft QCD and Diffraction and one on the Determination of CKM Angles from B Hadrons. The Review is divided into two volumes. Volume 1 includes the Summary Tables and 98 review articles. Volume 2 consists of the Particle Listings and contains also 22 reviews that address specific aspects of the data presented in the Listings. The complete Review (both volumes) is published online on the website of the Particle Data Group (pdg.lbl.gov) and in a journal. Volume 1 is available in print as the PDG Book. A Particle Physics Booklet with the Summary Tables and essential tables, figures, and equations from selected review articles is available in print and as a web version optimized for use on phones as well as an Android app.
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Punzi, G., Baldini, W., Bassi, G., Contu, A., Fantechi, R., He, J. B., et al. (2024). Detector-embedded reconstruction of complex primitives using FPGAs. Nucl. Instrum. Methods Phys. Res. A, 1069, 169782–4pp.
Abstract: The slowdown of Moore's law and the growing requirements of future HEP experiments with ever-increasing data rates pose important computational challenges for data reconstruction and trigger systems, encouraging the exploration of new computing methodologies. In this work we discuss a FPGA-based tracking system, relying on a massively parallel pattern recognition approach, inspired by the processing of visual images by the natural brain (“retina architecture”). This method allows a large efficiency of utilisation of the hardware, low power consumption and very low latencies. Based on this approach, a device has been designed within the LHCb Upgrade-II project, with the goal of performing track reconstruction in the forward acceptance region in real-time during the upcoming Run 4 of the LHC. This innovative device will perform track reconstruction before the event-building, in a short enough time to provide pre-reconstructed tracks (“primitives”) transparently to the processor farm, as if they had been generated directly by the detector. This allows significant savings in higher-level computing resources, enabling handling higher luminosities than otherwise possible. The feasibility of the project is backed up by the results of tests performed on a realistic hardware prototype, that has been opportunistically processing actual LHCb data in parallel with the regular DAQ in the LHC Run 3.
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Belle-II DEPFET and PXD Collaborations(Ahlburg, P. et al), & Marinas, C. (2024). The new and complete Belle II DEPFET pixel detector: Commissioning and previous operational experience. Nucl. Instrum. Methods Phys. Res. A, 1068, 169763–6pp.
Abstract: The Belle II experiment at the SuperKEKB collider in Tsukuba, Japan, has collected e+e- + e – collision data between 2019 and 2022. After reaching a record-breaking instantaneous luminosity of 4.71x1034 . 71x10 34 cm -2 s -1 and recording a dataset corresponding to 424 fb -1 , it completed its first planned long shutdown phase in December 2023. Aside from upgrades of the collider and detector maintenance, the shutdown was used for the installation of the two-layer Pixel VerteX Detector (PXD). As the innermost sub-detector, multiple scattering effects need to be reduced. PXD utilizes the Depleted P-channel Field Effect Transistor (DEPFET) technology, allowing for a material budget of 0.21% X0 0 per layer. Each of the tracker's 40 modules consists of an array of 250x768 pixels with a pitch ranging from 50 μmx 55 μm for the inner to 85 μmx 55 μm for the outer layer yielding high gain and high signal-to-noise ratio while retaining about 99% hit efficiency. This article discusses the experience of the 4-year operation of the previous single-layer PXD in harsh background conditions as well as commissioning and testing of the fully-populated PXD2 during Long Shutdown 1.
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