ترغب بنشر مسار تعليمي؟ اضغط هنا

We present results on the K*(892)+ production in proton-proton collisions at a beam energy of E = 3.5 GeV, which is hitherto the lowest energy at which this mesonic resonance has been observed in nucleon-nucleon reactions. The data are interpreted wi thin a two-channel model that includes the 3-body production of K*(892)+ associated with the Lambda- or Sigma-hyperon. The relative contributions of both channels are estimated. Besides the total cross section sigma(p+p -> K*(892)+ + X) = 9.5 +- 0.9 +1.1 -0.9 +- 0.7 mub, that adds a new data point to the excitation function of the K*(892)+ production in the region of low excess energy, transverse momenta and angular spectra are extracted and compared with the predictions of the two-channel model. The spin characteristics of K*(892)+ are discussed as well in terms of the spin-alignment.
Results on the production of the double-strange cascade hyperon $mathrm{Xi^-}$ 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. For the first time, subthreshold $mathrm{Xi^-}$ production is observed in proton-nucleus interactions. Assuming a $mathrm{Xi^-}$ phase-space distribution similar to that of $mathrm{Lambda}$ hyperons, the production probability amounts to $P_{mathrm{Xi^-}}=(2.0,pm0.4,mathrm{(stat)},pm 0.3,mathrm{(norm)},pm 0.6,mathrm{(syst)})times10^{-4}$ resulting in a $mathrm{Xi^-/(Lambda+Sigma^0)}$ ratio of $P_{mathrm{Xi^-}}/ P_{mathrm{Lambda+Sigma^0}}=(1.2pm 0.3,mathrm{(stat)}pm0.4,mathrm{(syst)})times10^{-2}$. Available model predictions are significantly lower than the estimated $mathrm{Xi^-}$ yield.
Employing the Bonn-Gatchina partial wave analysis framework (PWA), we have analyzed HADES data of the reaction $p(3.5GeV)+pto pK^{+}Lambda$. This reaction might contain information about the kaonic cluster $ppK^-$ via its decay into $pLambda$. Due to interference effects in our coherent description of the data, a hypothetical $overline{K}NN$ (or, specifically $ppK^-$) cluster signal must not necessarily show up as a pronounced feature (e.g. a peak) in an invariant mass spectra like $pLambda$. Our PWA analysis includes a variety of resonant and non-resonant intermediate states and delivers a good description of our data (various angular distributions and two-hadron invariant mass spectra) without a contribution of a $overline{K}NN$ cluster. At a confidence level of CL$_{s}$=95% such a cluster can not contribute more than 2-12% to the total cross section with a $pK^{+}Lambda$ final state, which translates into a production cross-section between 0.7 $mu b$ and 4.2 $mu b$, respectively. The range of the upper limit depends on the assumed cluster mass, width and production process.
The Mantid framework is a software solution developed for the analysis and visualization of neutron scattering and muon spin measurements. The framework is jointly developed by software engineers and scientists at the ISIS Neutron and Muon Facility a nd the Oak Ridge National Laboratory. The objectives, functionality and novel design aspects of Mantid are described.
We present the analysis of the inclusive $K^{0}$ 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 $approx 35$ 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.
Results on $Lambda$ 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 distribut ions in rapidity bins are well described by Boltzmann shapes with a maximum inverse slope parameter of about $90,$MeV at a rapidity of $y=1.0$, i.e. slightly below the center-of-mass rapidity for nucleon-nucleon collisions, $y_{cm}=1.12$. The rapidity density decreases monotonically with increasing rapidity within a rapidity window ranging from 0.3 to 1.3. The $Lambda$ phase-space distribution is compared with results of other experiments and with predictions of two transport approaches which are available publicly. None of the prese
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا