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A bstract At colliders, neutral long-lived particles can be detected through displaced decay products or as missing energy. Which search strategy is better depends on the particle’s decay length just as on the detector properties. We investigate the complementarity of displaced and invisible signatures for the Belle II experiment. Focusing on axion-like particles a produced from meson decays, we present a new search strategy for two-body decays with missing energy . With 50 ab − 1 of data, Belle II can probe light invisible resonances with branching ratio B ( B + → K + a ) ≳ 10 − 7 and decay length cτ a ≳ 1 m. For axion-like particles, we expect the sensitivity of to small couplings to improve by up to two orders of magnitude compared to previous searches at collider and fixed-target experiments. For sub-GeV particles, at Belle II and searches at beam-dump experiments are most sensitive; for heavier particles, searches for displaced vertices at Belle II, long-lived particle experiments at the LHC, and future fixed-target experiments can probe the smallest couplings.

Early sensory experience can exert lasting perceptual consequences. For example, a brief period of auditory deprivation early in life can lead to persistent spatial hearing deficits. Some forms of hearing loss (i.e., conductive; CHL) can distort acoustical cues needed for spatial hearing, which depend on inputs from both ears. We hypothesize that asymmetric acoustic input during development disrupts auditory circuits that integrate binaural information. Here, we identify prolonged maturation of the binaural auditory brainstem in the guinea pig by tracking auditory evoked potentials across development. Using this age range, we induce a reversible unilateral CHL and ask whether behavioral and neural maturation are disrupted. We find that developmental CHL is associated with alterations in a brainstem readout of binaural function, an effect that was not observed in a separate cohort with adult-onset CHL. Startle-based behavioral measures suggest that Early CHL animals exhibit reduced spatial resolution for high-frequency sound sources. Finally, single-unit recordings of auditory midbrain neurons reveal significantly poorer neural acuity to a sound location cue that largely depends on high-frequency sounds. Thus, these findings show that unilateral deprivation can disrupt developing auditory circuits that integrate binaural information and may give rise to lingering spatial hearing deficits.

Background: This narrative review explores psilocybin’s potential use as a therapeutic agent in patients with traumatic brain injury (TBI). Methods: We engaged in a search of PubMed, ScienceDirect, and Cochrane’s databases for information on the effects of psilocybin. We also reviewed articles where psilocybin was used in patients with TBI. Articles from 2000–2025 were included. Results: A total of 29 articles met our initial inclusion criteria. Additionally, 13 articles were obtained from reference lists and 3 more articles on the legality of psilocybin from public websites. Conclusions: Assisted psilocybin use may have benefits in TBI by reducing inflammation, promoting neuroplasticity and neuroregeneration, and alleviating associated mood disorders. Positive findings in related fields, like treatment for depression and addiction, highlight the necessity for more extensive clinical trials on psilocybin’s role in TBI recovery.

We present the study of an end-to-end multi-track reconstruction algorithm for the central drift chamber of the Belle II experiment at the SuperKEKB collider using Graph Neural Networks for an unknown number of particles. The algorithm uses detector hits as inputs without pre-filtering to simultaneously predict the number of track candidates in an event and their kinematic properties. In a second step, we cluster detector hits for each track candidate to pass to a track fitting algorithm. Using a realistic full detector simulation including beam-induced backgrounds and detector noise taken from actual collision data, we find significant improvements in track finding efficiencies for tracks in a variety of different event topologies compared to the existing baseline algorithm used in Belle II. For events involving a hypothetical long-lived massive particle with a mass in the GeV-range, decaying uniformly along its flight direction into two charged particles, the GNN achieves a combined track finding and fitting charge efficiency of 85.4% per track, with a fake rate of 2.5%, averaged over the full detector acceptance. In comparison, the baseline algorithm achieves 52.2% efficiency and a fake rate of 4.1%. This is the first end-to-end multi-track machine learning algorithm for a drift chamber detector that has been utilized in a realistic particle physics environment.

We present the novel implementation of a non-differentiable metric approximation and a corresponding loss-scheduling aimed at the search for new particles of unknown mass in high energy physics experiments. We call the loss-scheduling, based on the minimisation of a figure-of-merit related function typical of particle physics, a Punzi-loss function, and the neural network that utilises this loss function a Punzi-net. We show that the Punzi-net outperforms standard multivariate analysis techniques and generalises well to mass hypotheses for which it was not trained. This is achieved by training a single classifier that provides a coherent and optimal classification of all signal hypotheses over the whole search space. Our result constitutes a complementary approach to fully differentiable analyses in particle physics. We implemented this work using PyTorch and provide users full access to a public repository containing all the codes and a training example.

SuperKEKB, the next generation B factory, has been constructed in Japan as an upgrade of KEKB. This brand new e+ e- collider is expected to deliver a very large data set for the Belle II experiment, which will be 50 times larger than the previous Belle sample. Both the triggered physics event rate and the background event rate will be increased by at least 10 times than the previous ones, and will create a challenging data taking environment for the Belle II detector. The software system of the Belle II experiment is designed to execute this ambitious plan. A full detector simulation library, which is a part of the Belle II software system, is created based on Geant4 and has been tested thoroughly. Recently the library has been upgraded with Geant4 version 10.1. The library is behaving as expected and it is utilized actively in producing Monte Carlo data sets for various studies. In this paper, we will explain the structure of the simulation library and the various interfaces to other packages including geometry and beam background simulation.

We present the results of a search for the charged-lepton-flavor violating decays B ⁰→ K ^(*0) τ ^(±) ℓ ^(∓) , where ℓ ^(∓)is either an electron or a muon. The results are based on 365 fb ⁻¹and 711 fb ⁻¹datasets collected with the Belle II and Belle detectors, respectively. We use an exclusive hadronic B-tagging technique, and search for a signal decay in the system recoiling against a fully reconstructed B meson. We find no evidence for B ⁰→ K ^(*0) τ ^(±) ℓ ^(∓)decays and set upper limits on the branching fractions in the range of (2.9–6.4)×10 ⁻⁵at 90% confidence level. 19 pages, 4 figures

We perform the first search for$C\\!P$violation in${D_{(s)}^{+}\\to{}K_{S}^{0}K^{-}\\pi^{+}\\pi^{+}}$decays. We use a combined data set from the Belle and Belle II experiments, which study$e^+e^-$collisions at center-of-mass energies at or near the$\\Upsilon(4S)$resonance. We use 980 fb $^{-1}$of data from Belle and 428 fb $^{-1}$of data from Belle~II. We measure six$C\\!P$ -violating asymmetries that are based on triple products and quadruple products of the momenta of final-state particles, and also the particles' helicity angles. We obtain a precision at the level of 0.5% for$D^+\\to{}K_{S}^{0}K^{-}\\pi^{+}\\pi^{+}$decays, and better than 0.3% for$D^+_{s}\\to{}K_{S}^{0}K^{-}\\pi^{+}\\pi^{+}$decays. No evidence of$C\\!P$violation is found. Our results for the triple-product asymmetries are the most precise to date for singly-Cabibbo-suppressed$D^+$decays. Our results for the other asymmetries are the first such measurements performed for charm decays. 21 pages, 10 figures

Using data samples of 983.0 fb − 1 and 427.9 fb − 1 accumulated with the Belle and Belle II detectors operating at the KEKB and SuperKEKB asymmetric-energy e + e − colliders, singly Cabibbo-suppressed decays$ {\\Xi}_c^{+}\\to p{K}_S^0 $Ξ c + → p K S 0 ,$ {\\Xi}_c^{+}\\to \\Lambda {\\pi}^{+} $Ξ c + → Λ π + , and$ {\\Xi}_c^{+}\\to {\\Sigma}^0{\\pi}^{+} $Ξ c + → Σ 0 π + are observed for the first time. The ratios of branching fractions of$ {\\Xi}_c^{+}\\to p{K}_S^0 $Ξ c + → p K S 0 ,$ {\\Xi}_c^{+}\\to \\Lambda {\\pi}^{+} $Ξ c + → Λ π + , and$ {\\Xi}_c^{+}\\to {\\Sigma}^0{\\pi}^{+} $Ξ c + → Σ 0 π + relative to that of$ {\\Xi}_c^{+}\\to {\\Xi}^{-}{\\pi}^{+}{\\pi}^{+} $Ξ c + → Ξ − π + π + are measured to be$ {\\displaystyle \\begin{array}{c}\\frac{\\mathcal{B}\\left({\\Xi}_c^{+}\\to p{K}_S^0\\right)}{\\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Xi}^{-}{\\pi}^{+}{\\pi}^{+}\\right)}=\\left(2.47\\pm 0.16\\pm 0.07\\right)\\%,\\\ {}\\frac{\\mathcal{B}\\left({\\Xi}_c^{+}\\to \\Lambda {\\pi}^{+}\\right)}{\\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Xi}^{-}{\\pi}^{+}{\\pi}^{+}\\right)}=\\left(1.56\\pm 0.14\\pm 0.09\\right)\\%,\\\ {}\\frac{\\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Sigma}^0{\\pi}^{+}\\right)}{\\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Xi}^{-}{\\pi}^{+}{\\pi}^{+}\\right)}=\\left(4.13\\pm 0.26\\pm 0.22\\right)\\%.\\end{array}} $B Ξ c + → p K S 0 B Ξ c + → Ξ − π + π + = 2.47 ± 0.16 ± 0.07 % , B Ξ c + → Λ π + B Ξ c + → Ξ − π + π + = 1.56 ± 0.14 ± 0.09 % , B Ξ c + → Σ 0 π + B Ξ c + → Ξ − π + π + = 4.13 ± 0.26 ± 0.22 % . Multiplying these values by the branching fraction of the normalization channel,$ \\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Xi}^{-}{\\pi}^{+}{\\pi}^{+}\\right)=\\left(2.9\\pm 1.3\\right)\\% $B Ξ c + → Ξ − π + π + = 2.9 ± 1.3 % , the absolute branching fractions are determined to be$ {\\displaystyle \\begin{array}{c}\\mathcal{B}\\left({\\Xi}_c^{+}\\to p{K}_S^0\\right)=\\left(7.16\\pm 0.46\\pm 0.20\\pm 3.21\\right)\\times {10}^{-4},\\\ {}\\mathcal{B}\\left({\\Xi}_c^{+}\\to \\Lambda {\\pi}^{+}\\right)=\\left(4.52\\pm 0.41\\pm 0.26\\pm 2.03\\right)\\times {10}^{-4},\\\ {}\\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Sigma}^0{\\pi}^{+}\\right)=\\left(1.20\\pm 0.08\\pm 0.07\\pm 0.54\\right)\\times {10}^{-3}.\\end{array}} $B Ξ c + → p K S 0 = 7.16 ± 0.46 ± 0.20 ± 3.21 × 10 − 4 , B Ξ c + → Λ π + = 4.52 ± 0.41 ± 0.26 ± 2.03 × 10 − 4 , B Ξ c + → Σ 0 π + = 1.20 ± 0.08 ± 0.07 ± 0.54 × 10 − 3 . The first and second uncertainties above are statistical and systematic, respectively, while the third ones arise from the uncertainty in$ \\mathcal{B}\\left({\\Xi}_c^{+}\\to {\\Xi}^{-}{\\pi}^{+}{\\pi}^{+}\\right) $B Ξ c + → Ξ − π + π + .