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We report on new flavor tagging algorithms developed to determine the quark-flavor content of bottom ( ) mesons at Belle II. The algorithms provide essential inputs for measurements of quark-flavor mixing and charge-parity violation. We validate and evaluate the performance of the algorithms using hadronic decays with flavor-specific final states reconstructed in a data set corresponding to an integrated luminosity of 62.8 fb-1, collected at the resonance with the Belle II detector at the SuperKEKB collider. We measure the total effective tagging efficiency to be εeff=(30.0±1.2(stat)±0.4(syst))%for a category-based algorithm and εeff=(28.8±1.2(stat)±0.4(syst))%for a deep-learning-based algorithm.

A bstract Using 983.0 fb − 1 and 427.9 fb − 1 data samples collected with the Belle and Belle II detectors at the KEKB and SuperKEKB asymmetric energy e + e − colliders, respectively, we present studies of the Cabibbo-favored decays and , and the singly Cabibbo-suppressed decay . The ratios of branching fractions of and relative to that of are measured for the first time, while the ratio is also determined and improved by an order of magnitude in precision. The measured branching fraction ratios are Additionally, the ratio is measured to be 0 . 068 ± 0 . 010 ± 0 . 004. Here, the first and second uncertainties are statistical and systematic, respectively. Multiplying the ratios by the branching fraction of the normalization mode, , we obtain the following absolute branching fractions where the third uncertainties are from .

This chapter of the report of the “Flavor in the era of the LHC” Workshop discusses the theoretical, phenomenological and experimental issues related to flavor phenomena in the charged lepton sector and in flavor conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavor structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the standard model, presenting benchmarks for the discovery potential of forthcoming measurements both at the LHC and at low energy, and exploring options for possible future experiments.

IntroductionThe 2015 NCEPOD report1 found high rebleeding and mortality rates in patients with significant UGIB and recommended clearly documented rebleed plans. We audited the adequacy of rebleed plans at Nottingham University Hospitals, where 800 suspected UGIB patients are admitted annually.MethodPatients who underwent emergency endoscopy for suspected acute UGIB between June - August 2015 were identified. We analysed patient demographics, endoscopy (OGD) findings, re-bleed plans and clinical outcomes. Focused recommendations and education were delivered to all endoscopy unit staff. Re-audit was performed during June - July 2016 and outcomes compared.Results130 patients: 81 (62.6%) men, median (range) age 61 (14-92); 49 (37.4%) women, median (range) age 73 (34-96) years underwent urgent OGD following suspected acute UGIB between June -August 2015. 42 (32.3%) had endoscopic evidence of active UGIB (21 (16%) variceal haemorrhage (VH), and 21 (16%) non-variceal haemorrhage (NVH)) and 88 (67.7%) had no evidence of bleeding. Only 23.1% (n=30) who underwent urgent OGD had a re-bleed plan but was higher in those with (20/42 (47.6%); 11.9% re-bled, 5% mortality) rather than without (10/88 (11.4%); 5.7% re-bled; 0% mortality) endoscopic signs of bleeding.During the 4 week re-audit period after staff engagement and education, 42 patients (66.7% men, median age 60.5; 33.3% female, median age 77 years) underwent OGD for suspected UGIB. 21.4% had endoscopic evidence of active UGIB (7.1% VH; 14.3% NVH) and 78.6% had no evidence of bleeding. Rebleed plans improved overall from 23.1% to 46.3% and were higher in those with ((77.8%); 11.1% re-bled; 0% mortality) rather than without ((37.5%); 3.1% re-bled; 0% mortality) endoscopic signs of bleeding.Most frequent re-bleed plans were repeat OGD (34.7%), CT angiogram/interventional radiology (34.7%), conservative management (16.3%) or lower GI endoscopy (6.1%). Surgery was not recommended in any initial rebleed plan.ConclusionMost patients with suspected acute UGIB did not have endoscopic evidence of active bleeding, but still had rebleed rates of between 3%–11%. Clear documentation of rebleed plans initially was poor, but was better in those with endoscopic signs of active bleeding. Following focused education, rebleed plans improved substantially overall from 23.1% to 46.3%, particularly in those with active bleeding from 47.6% to 77.8%, who had a higher risk of rebleeding and in-hospital mortality.Reference. McPherson SJ, et al. Time to get Control; NCEPOD report 2015. Disclosure of InterestNone Declared

A bstract We present a measurement of the Cabibbo-Kobayashi-Maskawa unitarity triangle angle ϕ 3 (also known as γ ) using a model-independent Dalitz plot analysis of B + → D ( K S 0 h + h − ) h + , where D is either a D 0 or D ¯ 0 meson and h is either a π or K . This is the first measurement that simultaneously uses Belle and Belle II data, combining samples corresponding to integrated luminosities of 711 fb − 1 and 128 fb − 1 , respectively. All data were accumulated from energy-asymmetric e + e − collisions at a centre-of-mass energy corresponding to the mass of the Υ(4 S ) resonance. We measure ϕ 3 = (78 . 4 ± 11 . 4 ± 0 . 5 ± 1 . 0)°, where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is from the uncertainties on external measurements of the D -decay strong-phase parameters.

We present a measurement of the time-dependent CP asymmetry in decays using a data set of 365 fb−1 recorded by the Belle II experiment and the final data set of 711 fb−1 recorded by the Belle experiment at the Υ(4S) resonance. The direct and mixing-induced time-dependent CP violation parameters C and S are determined along with two additional quantities, S+ and S−, defined in the two halves of the plane. The measured values are C = −0.17 ± 0.09 ± 0.04, S = −0.29 ± 0.11 ± 0.05, S+ = −0.57 ± 0.23 ± 0.10 and S− = 0.31 ± 0.24 ± 0.05, where the first uncertainty is statistical and the second systematic.

The Belle II silicon vertex detector is one of the vertex detectors in the Belle II experiment. The detector reads out the signals from the double-sided silicon strip sensors with the APV25 front-end readout ASIC, adopting the chip-on-sensor concept to minimize the strip noise. The detector has been operated in the experiment since the spring of 2019. Analyzing the acquired data during the beam collisions, the excellent performance of the detector is confirmed. Also, the radiation dose and 1-MeV equivalent neutron fluence of the detector are estimated using the measured dose rates of the diamond sensors installed on the beam pipe and are compared with the measured radiation effects in the strip noise, leakage current, and depletion voltage. This paper briefly introduces the main features of the silicon vertex detector, and then reports on the measured performance and radiation effects of the first two years of running experience of the detector.

Inelastic dark matter models that have two dark matter particles and a massive dark photon can reproduce the observed relic dark matter density without violating cosmological limits. The mass splitting between the two dark matter particles \\(\\chi_{1}\\) and \\(\\chi_{2}\\), with \\(m(\\chi_{2}) > m(\\chi_{1})\\), is induced by a dark Higgs field and a corresponding dark Higgs boson \\(h^{\\prime}\\). We present a search for dark matter in events with two vertices, at least one of which must be displaced from the interaction region, and missing energy. Using a \\(365\\,\\mbox{fb}^{-1}\\) data sample collected at Belle II, which operates at the SuperKEKB \\(e^+e^-\\) collider, we observe no evidence for a signal. We set upper limits on the product of the production cross section \\(\\sigma\\left(e^+e^- \\to h^\\prime \\chi_1 \\chi_2\\right)\\), and the product of branching fractions \\(\\mathcal{B}\\left(\\chi_2\\to\\chi_1 e^+ e^-\\right)\\times\\mathcal{B}\\left(h^\\prime\\to x^+x^-\\right)\\), where \\(x^+x^-\\) indicates \\(\\mu^+\\mu^-, \\pi^+\\pi^-\\), or \\(K^+K^-\\), as functions of \\(h^{\\prime}\\) mass and lifetime at the level of \\(10^{-1}\\,\\mbox{fb}\\). We set model-dependent upper limits on the dark Higgs mixing angle at the level of \\(10^{-5}\\) and on the dark photon kinetic mixing parameter at the level of \\(10^{-3}\\). This is the first search for dark Higgs bosons in association with inelastic dark matter.

A series of data samples was collected with the Belle~II detector at the SuperKEKB collider from March 2019 to June 2022. We determine the integrated luminosities of these data samples using three distinct methodologies involving Bhabha (\\(e^+e^- \\to e^+e^-(n\\gamma)\\)), digamma (\\(e^+e^- \\to \\gamma\\gamma(n\\gamma)\\)), and dimuon (\\(e^+e^- \\to \\mu^+ \\mu^- (n\\gamma)\\)) events. The total integrated luminosity obtained with Bhabha, digamma, and dimuon events is ({426.88} \\(\\pm\\) 0.03 \\(\\pm\\) {2.61})~fb\\(^{-1}\\), ({429.28} \\(\\pm\\) 0.03 \\(\\pm\\) {2.62})~fb\\(^{-1}\\), and ({423.99} \\(\\pm\\) 0.04 \\(\\pm\\) {3.83})~fb\\(^{-1}\\), where the first uncertainties are statistical and the second are systematic. The resulting total integrated luminosity obtained from the combination of the three methods is ({427.87 \\(\\pm\\) 2.01})~fb\\(^{-1}\\).