Spatially-resolved potential measurement with ion crystals

We present a method to measure potentials over an extended region using one-dimensional ion crystals in a radio frequency (RF) ion trap. The equilibrium spacings of the ions within the crystal allow the determination of the external forces acting at each point. From this the overall potential, and also potentials due to specific trap features, are calculated. The method can be used to probe potentials near proximal objects in real time, and can be generalized to higher dimensions.Comment: 7 pages (double spaced), 3 figure

Hadronic Mass Spectrum Analysis of D+ into K- pi+ mu+ nu Decay and Measurement of the K*(892)^0 Mass and Width

We present a Kpi mass spectrum analysis of the four-body semileptonic charm decay D+ into K- pi+ mu+ nu in the range of 0.65 GeV < mKpi < 1.5 GeV. We observe a non-resonant contribution of 5.30 +- 0.74 +0.99 -0.51 % with respect to the total D+ into K- pi+ mu+ nu decay. For the K*(892)^0 resonance, we obtain a mass of 895.41 +- 0.32 +0.35 -0.36 MeV, a width of 47.79 +- 0.86 +1.3 -1.1 MeV, and a Blatt-Weisskopf damping factor parameter of 3.96 +- 0.54 +0.72 -0.90 GeV^(-1). We also report 90 % CL upper limits of 4 % and 0.64 % for the branching ratios of D+ into K*(1680)^0 mu+ nu with respect to D+ into K- pi+ mu+ nu and D+ into K*(1430)^0 mu+ nu with respect to D+ into K- pi+ mu+ nu, respectively.Comment: 14 page

Production of Lambda and Sigma^0 hyperons in proton-proton collisions

This paper reports results on simultaneous measurements of the reaction channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239, and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and differential cross sections are given for both reactions. It is concluded from the measured total cross sections that the high energy limit of the cross section ratio is almost reached at an excess energy of only about 200 MeV. From the differential distributions observed in the overall CMS as well as in the Jackson and helicity frames, a significant contribution of interfering nucleon resonances to the \Lambda production mechanism is concluded while resonant \Sigma^0-production seems to be of lesser importance and takes place only through specific partial waves of the entrance channel. The data also indicate that kaon exchange plays a minor role in the case of \Lambda- but an important role for \Sigma^0-production. Thus the peculiar energy dependence of the \Lambda-to-\Sigma^0 cross section ratio appears in a new light as its explanation requires more than mere differences between the p\Lambda and the p\Sigma^0 final state interaction. The data provide a benchmark for theoretical models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A (EPJ A

Study of the decay mode D^0 -> K-K-K+pi+

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode $D^0 \to K^-K^-K^+\pi^+$. From a sample of $143 \pm 19$ fully reconstructed $D^0 \to K^-K^-K^+\pi^+$ events, we measure $\Gamma(D^0 \to K^-K^-K^+\pi^+)/\Gamma(D^0 \to K^-\pi^-\pi^+\pi^+) = 0.00257 \pm 0.00034(stat.) \pm 0.00024(syst.)$. A coherent amplitude analysis has been performed to determine the resonant substructure of this decay mode. This analysis reveals a dominant contribution from $\phi$ and $\bar K^{*0}(890)$ states.Comment: 15 pages, 4 figures, to be submitted to Physics Letters

The K−π+K^-\pi^+ S-wave from the D+→K−π+π+D^+ \to K^-\pi^+\pi^+ decay

Using data from FOCUS (E831) experiment at Fermilab, we present a model independent partial-wave analysis of the $K^-\pi^+$ S-wave amplitude from the decay $D^+ \to K^-\pi^+\pi^+$. The S-wave is a generic complex function to be determined directly from the data fit. The P- and D-waves are parameterized by a sum of Breit-Wigner amplitudes. The measurement of the S-wave amplitude covers the whole elastic range of the $K^-\pi^+$ system.Comment: 13 pages, 9 figures, submitted to Physics Letters

Study of the decay mode D^0 -> K-K+pi-pi+

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement of the branching ratio for the Cabibbo-favored decay mode $D^0 \to K^-K^+\pi^-\pi^+$. From a sample of $2669 \pm 101$ fully reconstructed $D^0 \to K^-K^+\pi^-\pi^+$ events, we measure $\Gamma(D^0 \to K^-K^+\pi^-\pi^+)/\Gamma(D^0 \to K^-\pi^-\pi^+\pi^+) = 0.0295 \pm 0.0011(stat.) \pm 0.0008(syst.)$. A coherent amplitude analysis has been performed to determine the resonant substructure of this decay mode. This analysis reveals a dominant contribution from $D^0 \to K_1^+ K-$ modes.Comment: 19 pages, 6 figures, to be submitted to Physics Letters

Pregnancy in women with hypertrophic cardiomyopathy: data from the European Society of Cardiology initiated Registry of Pregnancy and Cardiac disease (ROPAC)

Aims We report the maternal and foetal outcomes at birth and after 6 months in a cohort of pregnant women with hypertrophic cardiomyopathy (HCM). Although most women with HCM tolerate pregnancy well, there is an increased risk of obstetric and cardiovascular complications. Methods and results All pregnant women with HCM entered into the prospective worldwide Registry of Pregnancy and Cardiac disease (ROPAC) were included in this analysis. The primary endpoint was a major adverse cardiovascular event (MACE), which included death, heart failure (HF), thrombo-embolic event, and arrhythmia. Baseline and outcome data were analysed and compared for patients with MACE vs. without MACE and for patients with obstructive HCM vs. non-obstructive HCM. Sixty pregnant women (mean age 30.4 +/- 6.0 years) with HCM (41.7% obstructive) were included. No maternal mortality occurred in this cohort. In 14 (23%) patients at least one MACE occurred: 9 (15.0%) HF and 7 (12%) an arrhythmia (6 ventricular and 1 atrial fibrillation). MACE occurred most commonly during the 3rd trimester and postpartum period. In total, 3 (5.0%) women experienced foetal loss. Women with MACE had a higher rate of emergency Caesarean delivery for cardiac reasons (21.4% vs. 0%, P = 0.01). No significant differences in pregnancy outcome were found between women with obstructive and non-obstructive HCM. NYHA functional class of >= II and signs of HF before pregnancy, were associated with MACE. Conclusion Although most women with HCM tolerated pregnancy well, cardiovascular complications were not uncommon and predicted by pre-pregnancy status facilitating pre-pregnancy counselling and targeted antenatal care