168 research outputs found
Second trimester inflammatory and metabolic markers in women delivering preterm with and without preeclampsia.
ObjectiveInflammatory and metabolic pathways are implicated in preterm birth and preeclampsia. However, studies rarely compare second trimester inflammatory and metabolic markers between women who deliver preterm with and without preeclampsia.Study designA sample of 129 women (43 with preeclampsia) with preterm delivery was obtained from an existing population-based birth cohort. Banked second trimester serum samples were assayed for 267 inflammatory and metabolic markers. Backwards-stepwise logistic regression models were used to calculate odds ratios.ResultsHigher 5-α-pregnan-3β,20α-diol disulfate, and lower 1-linoleoylglycerophosphoethanolamine and octadecanedioate, predicted increased odds of preeclampsia.ConclusionsAmong women with preterm births, those who developed preeclampsia differed with respect metabolic markers. These findings point to potential etiologic underpinnings for preeclampsia as a precursor to preterm birth
The interaction studied via femtoscopy in p + Nb reactions at
We report on the first measurement of and correlations via
the femtoscopy method in p+Nb reactions at , studied with the High Acceptance Di-Electron Spectrometer
(HADES). By comparing the experimental correlation function to model
calculations, a source size for pairs of and a slightly
smaller value for of is extracted.
Using the geometrical extent of the particle emitting region, determined
experimentally with correlations as reference together with a source
function from a transport model, it is possible to study different sets of
scattering parameters. The correlation is proven sensitive to
predicted scattering length values from chiral effective field theory. We
demonstrate that the femtoscopy technique can be used as valid alternative to
the analysis of scattering data to study the hyperon-nucleon interaction.Comment: 12 pages, 11 figure
Searching a Dark Photon with HADES
We present a search for the e+e- decay of a hypothetical dark photon, also
names U vector boson, in inclusive dielectron spectra measured by HADES in the
p (3.5 GeV) + p, Nb reactions, as well as the Ar (1.756 GeV/u) + KCl reaction.
An upper limit on the kinetic mixing parameter squared epsilon^{2} at 90% CL
has been obtained for the mass range M(U) = 0.02 - 0.55 GeV/c2 and is compared
with the present world data set. For masses 0.03 - 0.1 GeV/c^2, the limit has
been lowered with respect to previous results, allowing now to exclude a large
part of the parameter region favoured by the muon g-2 anomaly. Furthermore, an
improved upper limit on the branching ratio of 2.3 * 10^{-6} has been set on
the helicity-suppressed direct decay of the eta meson, eta-> e+e-, at 90% CL
Inclusive pion and eta production in p+Nb collisions at 3.5 GeV beam energy
Data on inclusive pion and eta production measured with the dielectron
spectrometer HADES in the reaction p+93Nb at a kinetic beam energy of 3.5 GeV
are presented. Our results, obtained with the photon conversion method,
supplement the rather sparse information on neutral meson production in
proton-nucleus reactions existing for this bombarding energy regime. The
reconstructed e+e-e+e- transverse-momentum and rapidity distributions are
confronted with transport model calculations, which account fairly well for
both pi0 and eta production.Comment: 12 pages, 9 figures, submitted to Physical Review
Medium effects in proton-induced production at 3.5 GeV
We present the analysis of the inclusive production in p+p and p+Nb
collisions measured with the HADES detector at a beam kinetic energy of 3.5
GeV. Data are compared to the GiBUU transport model. The data suggest the
presence of a repulsive momentum-dependent kaon potential as predicted by the
Chiral Perturbation Theory (ChPT). For the kaon at rest and at normal nuclear
density, the ChPT potential amounts to MeV. A detailed tuning of
the kaon production cross sections implemented in the model has been carried
out to reproduce the experimental data measured in p+p collisions. The
uncertainties in the parameters of the model were examined with respect to the
sensitivity of the experimental results from p+Nb collisions to the in-medium
kaon potential.Comment: 13 pages, 14 figure
Baryonic resonances close to the Kbar-N threshold: the case of Sigma(1385)^+ in pp collisions
We present results of an exclusive measurement of the first excited state of
the Sigma hyperon, Sigma(1385)^+, produced in p+p -> Sigma^+ + K^+ + n at 3.5
GeV beam energy. The extracted data allow to study in detail the invariant mass
distribution of the Sigma(1385)^+. The mass distribution is well described by a
relativistic Breit-Wigner function with a maximum at m_0 = 1383.2 +- 0.9
MeV/c^2 and a width of 40.2 +- 2.1 MeV/c^2. The exclusive production
cross-section comes out to be 22.27 +- 0.89 +- 1.56 +3.07 -2.10 mu b. Angular
distributions of the Sigma(1385)^+ in different reference frames are found to
be compatible with the hypothesis that 33 % of Sigma(1385)^+ result from the
decay of an intermediate Delta^{++} resonance.Comment: 12 pages; 12 figures; submitted to PR
Production of Sigma{\pm}pi?pK+ in p+p reactions at 3.5 GeV beam energy
We study the production of Sigma^+-pi^+-pK^+ particle quartets in p+p
reactions at 3.5 GeV kinetic beam energy. The data were taken with the HADES
experiment at GSI. This report evaluates the contribution of resonances like
Lambda(1405$, Sigma(1385)^0, Lambda(1520), Delta(1232), N^* and K^*0 to the
Sigma^+- pi^-+ p K+ final state. The resulting simulation model is compared to
the experimental data in several angular distributions and it shows itself as
suitable to evaluate the acceptance corrections properly.Comment: 15 pages, 5 figure
Lambda hyperon production and polarization in collisions of p(3.5 GeV) + Nb
Results on hyperon production are reported for collisions of p(3.5
GeV) + Nb, studied with the High Acceptance Di-Electron Spectrometer (HADES) at
SIS18 at GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt. The transverse
mass distributions in rapidity bins are well described by Boltzmann shapes with
a maximum inverse slope parameter of about MeV at a rapidity of ,
i.e. slightly below the center-of-mass rapidity for nucleon-nucleon collisions,
. The rapidity density decreases monotonically with increasing
rapidity within a rapidity window ranging from 0.3 to 1.3. The
phase-space distribution is compared with results of other experiments and with
predictions of two transport approaches which are available publicly. None of
the present versions of the employed models is able to fully reproduce the
experimental distributions, i.e. in absolute yield and in shape. Presumably,
this finding results from an insufficient modelling in the transport models of
the elementary processes being relevant for production, rescattering
and absorption. The present high-statistics data allow for a genuine
two-dimensional investigation as a function of phase space of the
self-analyzing polarization in the weak decay . Finite negative values of the polarization in the order of
are observed over the entire phase space studied. The absolute value of the
polarization increases almost linearly with increasing transverse momentum for
MeV/c and increases with decreasing rapidity for .Comment: accepted by Eur. Phys. J.
- …