New precise measurements of radiative charged kaon and hyperon decays

New results in the radiative decay of charged kaons sector are presented by the NA48/2 experiment at CERN: the first measurement of the DE and INT contribution to the decay $K^{\pm} \rightarrow \pi^{\pm}\pi^{0}\gamma$ in the $T^{∗}_{\pi}$ region $0 < T^{∗}_{\pi} < 80$ Mev and the first observation of $K^{\pm} \rightarrow \pi^{\pm}e^{+}e^{-}\gamma$ decay. Also new results in the radiative decay of hyperons are presented by NA48/1: the measurement of $\Xi^{0} \rightarrow \Lambda\gamma$ decay asymmetry and the first observation of the $\Xi^{0} \rightarrow \Lambda e^{+}e^{−}$ decay

Relevant results from the NA48 experiment

We report relevant results from NA48 experiment at CERN SPS. NA48 was proposed in 1990 \cite{proposal} to study direct CP violation in $K^0\to\pi\pi$ to a level of accuracy sufficient to resolve the inconclusive status left by the previous measurements performed by NA31 \cite{NA31} and E731 \cite{E731}. In 2002 NA48 published the final result \cite{NA48epsoeps}. Small modification to the experimental setup have allowed NA48 to go forward with an extensive investigation of $K^0$ rare decays and hyperon decays. Some results are already available and reported here together with the final CP violation measurement.Comment: 3 pages, 1 eps figure, XXIII Physics in collisio

Integrated Trigger and Data Acquisition system for the NA62 experiment at CERN

The main goal of the NA62 experiment is to measure the branching ratio of the K+decay, collecting O(100) events in two years of data taking. Efficient online selection of interesting events and loss-less readout at high rate will be key issues for such experiment. An integrated trigger and data acquisition system has been designed. Only the very first trigger stage will be implemented in hardware, in order to reduce the total rate for the software levels on PC farms. Readout uniformity among different subdetectors and scalability were taken into account in the architecture design

Measurement of the branching ratio of the decay Ξ0→Σ+μ−νˉμ\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}

From the 2002 data taking with a neutral kaon beam extracted from the CERN-SPS, the NA48/1 experiment observed 97 $\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}$ candidates with a background contamination of $30.8 \pm 4.2$ events. From this sample, the BR($\Xi^{0}\rightarrow \Sigma^{+} \mu^{-} \bar{\nu}_{\mu}$) is measured to be $(2.17 \pm 0.32_{\mathrm{stat}}\pm 0.17_{\mathrm{syst}})\times10^{-6}$

Recent NA48/2 and NA62 results

The NA48/2 Collaboration at CERN has accumulated and analysed unprecedented statistics of rare kaon decays in the $K_{e4}$ modes: $K_{e4}(+-)$ ($K^\pm \to \pi^+ \pi^- e^\pm \nu$) and $K_{e4}(00)$ ($K^\pm \to \pi^0 \pi^0 e^\pm \nu$) with nearly one percent background contamination. It leads to the improved measurement of branching fractions and detailed form factor studies. New final results from the analysis of 381 $K^\pm \to \pi^\pm \gamma \gamma$ rare decay candidates collected by the NA48/2 and NA62 experiments at CERN are presented. The results include a decay rate measurement and fits to Chiral Perturbation Theory (ChPT) description.Comment: Prepared for the Proceedings of "Moriond QCD and High Energy Interactions. March 22-29 2014." conferenc

Measurement of K^0_e3 form factors

The semileptonic decay of the neutral K meson, KL -> pi e nu (Ke3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f_+(q^2)), scalar (f_S) and tensor (f_T) interactions were measured. The linear slope of the vector form factor lambda_+ = 0.0284+-0.0007+-0.0013 and values for the ratios |f_S/f_+(0)| = 0.015^{+0.007}_{-0.010}+-0.012 and |f_T/f_+(0)| = 0.05^{+0.03}_{-0.04}+-0.03 were obtained. The values for f_S and f_T are consistent with zero. Assuming only Vector-Axial vector couplings, lambda_+ = 0.0288+-0.0004+-0.0011 and a good fit consistent with pure V-A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M = 859+-18 MeV, consistent with the K^*(892) mass.Comment: 16 pages, 7 figures. submitted to Phys. Lett.

Maternal-foetal complications in pregnancy: a retrospective comparison between type 1 and type 2 diabetes mellitus.

Background: The aim of the study was a retrospective comparison of the differences in maternal-foetal outcomes between women with type 1 and type 2 diabetes mellitus (T1DM and T2DM). Methods: A cohort of 135 patients with pregestational diabetes, 73 with T1DM (mean age 29 ± 5 years) and 62 with T2DM (mean age 33 ± 6 years), in intensive insulin treatment throughout pregnancy were evaluated. Clinical and metabolic parameters and the prevalence of maternal and foetal complications were assessed. Results: Women with T1DM showed lower pregestational BMI (p &lt; 0.001), pregestational weight (p &lt; 0.001), weight at delivery (p &lt; 0.001), ∆_total_insulin requirement (IR) at the first, second and third trimesters (all p &lt; 0.001) and higher weight gain during pregnancy (p &lt; 0.001), pregestational HbA1c (p = 0.040), HbA1c in the first (p = 0.004), second (p = 0.020) and third (p = 0.010) trimesters compared to T2DM. Women with T1DM had a higher risk of macrosomia (p = 0.005) than T2DM, while women with T2DM showed higher prevalence of abortion (p = 0.037) than T1DM. At multivariate analysis, pregestational BMI and ∆_total_IR of the first trimester were independently associated with abortion in T2DM, while weight gain during pregnancy was independently associated with macrosomia in T1DM. Conclusion: Women with T1DM have a higher risk of macrosomia than T2DM due to weight gain throughout pregnancy. By contrast, women with T2DM have a higher risk of spontaneous abortion than T1DM, due to pregestational BMI and ∆_total_IR in the first trimester

Observation of the rare decay K_S -> pi^0mu^+mu^-

A search for the decay K_S -> pi^0mu^+mu^- has been made by the NA48/1 Collaboration at the CERN SPS accelerator. The data were collected during 2002 with a high-intensity K_S beam. Six events were found with a background expectation of 0.22^+0.18_-0.11 event. Using a vector matrix element and unit form factor, the measured branching ratio is B(K_S -> pi^0mu^+mu^-)=[2.9^+1.5_-1.2(stat)+/-0.2(syst)]x10^{-9}.Comment: 19 pages, 8 figures, 4 tables. To be published in Physics Letters

First observation and branching fraction and decay parameter measurements of the weak radiative decay Xi0 --> Lambda e+e-

The weak radiative decay Xi0 --> Lambda e+e- has been detected for the first time. We find 412 candidates in the signal region, with an estimated background of 15 +/- 5 events. We determine the branching fraction B(Xi0 --> Lambda e+e-) = [7.6 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(norm)] x 10^{-6}, consistent with an internal bremsstrahlung process, and the decay asymmetry parameter alpha_{XiLambdaee} = -0.8 +/- 0.2, consistent with that of Xi0 --> Lambda gamma. The charge conjugate reaction Xi0_bar --> Lambda_bar e+e- has also been observed.Comment: 20 pages, 5 figures, 4 tables; revised: 19 pages, 4 figures, 4 tables, after reviewers' comments: 1 figure removed, 1 figure corrected, minor editorial changes; to be published in Phys. Lett.