Measurement of the decays B → η ℓ ν ℓ and B → η ′ ℓ ν ℓ in fully reconstructed events at Belle

We report branching fraction measurements of the decays B+→ηℓ+νℓ and B+→η′ℓ+νℓ based on 711 fb−1 of data collected near the Υ(4S) resonance with the Belle experiment at the KEKB asymmetric-energy e+e− collider. This data sample contains 772 million B¯B events. One of the two Bmesons is fully reconstructed in a hadronic decay mode. Among the remaining (“signal-B”) daughters, we search for the η meson in two decay channels, η→γγ and η→π+π−π0, and reconstruct the η′meson in η′→ηπ+π− with subsequent decay of the η into γγ. Combining the two η modes and using an extended maximum likelihood, the B+→ηℓ+νℓ branching fraction is measured to be (4.2±1.1(stat.)±0.3(syst.))×10−5. For B+→η′ℓ+νℓ, we observe no significant signal and set an upper limit of 0.72×10−4 at 90% confidence level

Measurement of the Branching Fractions of the B\u3csup\u3e+\u3c/sup\u3e → \u3ci\u3eη\u3c/i\u3e′ℓ+νℓ and B\u3csup\u3e+\u3c/sup\u3e → \u3ci\u3eη\u3c/i\u3e′ℓ+νℓ Decays with Signal-Side Only Reconstruction in the Full q\u3csup\u3e2\u3c/sup\u3e Range

The branching fractions of the decays B+ → ηl+νl and B+ → ηl+νl are measured, where l is either an electron or a muon, using a data sample of 711 fb−1 containing 772 × 106 BB̅ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. To reduce the dependence of the result on the form factor model, the measurement is performed over the entire q2 range. The resulting branching fractions are B(B+ → η ℓ + ν ℓ)=(2.83 ± 0.55 (stat.) ± 0.34(syst.)) x 10-5 and B(B+→η′ℓ+νℓ)=(2.79 ±1.29(stat.) ± 0.30(syst.))×10−5

Comeback Measurement of the CKM Matrix Element |V\u3csub\u3ecb\u3c/sub\u3e| From B\u3csup\u3e0\u3c/sup\u3e → D\u3csup\u3e*-\u3c/sup\u3e at Belle

We present a new measurement of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| from B0 → D*-ℓ vℓ decays, reconstructed with the full Belle data set of 711 fb−1 integrated luminosity. Two form factor parametrizations, originally conceived by the Caprini-Lellouch-Neubert (CLN) and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product F(1)ηEW||Vcb| and the decay form factors, where F(1) is the normalization factor and ηEW is a small electroweak correction. In the CLN parametrization we find F(1)ηEW||Vcb|=(35.06 ± 0.15 ± 0.56) × 10−3, ρ2 =1.106 ± 0.031± 0.007, R1(1) ¼ 1.229 ± 0.028 ± 0.009, R2(1) = 0.852 ± 0.021 ± 0.006. For the BGL parametrization we obtain F(1)ηEW|Vcb|=(34.93 ± 0.23 ± 0.59) × 10−3, which is consistent with the world average when correcting for F(1) ηEW. The branching fraction of B0 → D−lþνl is measured to be B(B0 → D−lþνlÞ¼ð4.90 0.02 0.16Þ%. We also present a new test of lepton flavor universality violation in semileptonic B decays, BðB0→D−eþνÞ BðB0→D−μþνÞ ¼ 1.01 0.01 0.03. The errors quoted correspond to the statistical and systematic uncertainties, respectively. This is the most precise measurement of Fð1ÞηEWjVcbj and form factors to date and the first experimental study of the BGL form factor parametrization in an experimental measurement

Search for the Lepton-Flavour Violating Decays B\u3csup\u3e0\u3c/sup\u3e→K\u3csup\u3e∗0\u3c/sup\u3eμ \u3csup\u3e±\u3c/sup\u3e e \u3csup\u3e∓\u3c/sup\u3e

We have searched for the lepton-flavor-violating decay B0 → K*0μ ±e∓ using a data sample of 711 fb−1 that contains 772 × 106 B B̅ pairs. The data were collected near the ϒð4SÞresonance with the Belle detector at the KEKB asymmetric-energy eþe− collider. No signals were observed, and we set 90% confidence level upper limits on the branching fractions of B(B0 →K*0μ+e−)\u3c1.2×10−7, B(B0 → K*0μ−e+) \u3c 1.6 × 10−7, and, for both decays combined, B(B0 → K*0μ±e∓) \u3c 1.8 × 10−7. These are the most stringent limits on these decays to date

Measurement of the Branching Fraction and Time-Dependent CP Asymmetry for B0→J/ψπ0 Decays

We measure the branching fraction and time-dependent CP-violating asymmetry for B0 → J=ψπ0 decays using a data sample of 711 fb−1 collected on the ϒ(4S) resonance by the Belle experiment running at the KEKB e+e− collider. The branching fraction is measured to be B(B0 → J/ψπ0) ¼ [1.62 ± 0.11(stat) ± 0.06(syst) × 10−5, which is the most precise measurement to date. The measured CP asymmetry parameters are S =−0.59 ±0.19(stat) 0.03(syst) and A = −0.15 ± 0.14(stat) +0.04 −0.03 (syst). The mixing-induced CP asymmetry (S) differs from the case of no CP violation by 3.0 standard deviations, and the direct CP asymmetry (A) is consistent with zero

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58\ub75%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31\ub72%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10\ub72%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12\ub73%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9\ub74%] of 7339 patients), middle (549 [14\ub70%] of 3918 patients), and low (298 [23\ub72%] of 1282) HDI (p<0\ub7001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17\ub78%] of 574 patients in high-HDI countries; 74 [31\ub74%] of 236 patients in middle-HDI countries; 72 [39\ub78%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1\ub760, 95% credible interval 1\ub705\u20132\ub737; p=0\ub7030). 132 (21\ub76%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16\ub76%) of 295 patients in high-HDI countries, in 37 (19\ub78%) of 187 patients in middle-HDI countries, and in 46 (35\ub79%) of 128 patients in low-HDI countries (p<0\ub7001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication. Funding: DFID-MRC-Wellcome Trust Joint Global Health Trial Development Grant, National Institute of Health Research Global Health Research Unit Grant