Punzi-loss:: a non-differentiable metric approximation for sensitivity optimisation in the search for new particles.

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.

Measurement of R(D) and R(D

The experimental results on the ratios of branching fractions R(D)=B(B[over ¯]→Dτ^{-}ν[over ¯]_{τ})/B(B[over ¯]→Dℓ^{-}ν[over ¯]_{ℓ}) and R(D^{*})=B(B[over ¯]→D^{*}τ^{-}ν[over ¯]_{τ})/B(B[over ¯]→D^{*}ℓ^{-}ν[over ¯]_{ℓ}), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D^{*}), based on a data sample containing 772×10^{6} BB[over ¯] events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D^{*})=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D^{*}), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D^{*}) performed to date as well as the first result for R(D) based on a semileptonic tagging method.

Measurement of the Direct CP Asymmetry in B¯â†’X(s+dγ) Decays with a Lepton Tag.

We report the measurement of the direct CP asymmetry in the radiative B¯â†’X(s+dγ) decay using a data sample of (772 ± 11)×10(6) BB[over ¯] pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The CP asymmetry is measured as a function of the photon energy threshold. For Eγ*≥2.1 GeV, where Eγ* is the photon energy in the center-of-mass frame, we obtain A(CP)(B¯â†’X(s+dγ))=(2.2±3.9±0.9)%, consistent with the standard model prediction.

[Assessment of the intervention in a therapeutic feeding center for children in Nicaragua]. / Evaluación de la intervención terapéutica realizada en un centro de recuperación nutricional infantil de Nicaragua.

INTRODUCTION: Child malnutrition carries a high morbimortality worldwide. Therapeutic feeding centers are essential in the treatment of malnourished children. OBJECTIVE: To evaluate the effectiveness of the therapeutic intervention in under-5 undernourished children in a Therapeutic Feeding Center. METHODS: A retrospective descriptive research was made through the revision of the clinical histories of children under 5 years that entered the Nutritional Recovery Center for Children in Matagalpa, Nicaragua, from January 2006 to July 2010. RESULTS: Median age at admission was 17.2 months (p25:10.7-p75:27.2) and median stay in the center was 92 days (p25:61.5-p75:134.5). Prevalence of patients with severe acute malnutrition was 45%, moderate acute malnutrition 24% and risk for malnutrition 31%. At discharge 86% of patients were properly nourished. Median weight gain percentage after the first month in the center was 15% (p25:12.6-p75:17.4). Median weight gain was 3.7 g/kg/day (p25:2.6-p75:5.4), being higher in children under 6 months (4.6 g/kg/day; p25:4.3-p75:7.5). Cured rate in the center was 87.5%, being the death rate 0% and the abandonment rate 9%. DISCUSSION: The center evaluated works adequately, and fulfills the internationally recommended quality indicators. However, recommended average stay of 1-2 months and average weight gain of 8 g/kg/day are far of being fulfilled. Therefore, the Nutritional Recovery Center performs an effective intervention, but it's not efficient enough.

Measurement of |V{ub}| from inclusive charmless semileptonic B decays.

We present the partial branching fraction for inclusive charmless semileptonic B decays and the corresponding value of the Cabibbo-Kobayashi-Maskawa matrix element |V{ub}|, using a multivariate analysis method to access approximately 90% of the B-->X{u}lnu phase space. This approach dramatically reduces the theoretical uncertainties from the b-quark mass and nonperturbative QCD compared to all previous inclusive measurements. The results are based on a sample of 657x10{6} BB[over ] pairs collected with the Belle detector. We find that DeltaB(B-->X{u}lnu;p(l){*B}>1.0 GeV/c)=1.963x(1+/-0.088{stat}+/-0.081{syst})x10{-3}. Corresponding values of |V{ub}| are extracted using several theoretical calculations.