Percorrer por autor "HADES collaboration (98 authors)"
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- Double pion production in np and pp collisions at 1.25 GeV with HADESPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.
- In-medium hadron properties measured with HADESPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.
- K*(892)$^+$ production in proton-proton collisions at $E_{beam}=$ 3.5 GeVPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.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 within a two-channel model that includes the three-body production of K*(892)+ associated with the Λ or Σ hyperon. The relative contributions of both channels are estimated. Besides the total cross section σ(p+p→K*(892)++X)=9.5±0.9−0.9+1.1±0.7μb, which 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.
- Lambda hyperon production and polarization in collisions of p(3.5 GeV)+NbPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.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 distributions 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 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 $\Lambda$ 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 $\Lambda$ polarization in the weak decay $\Lambda\rightarrow p \pi^-$. Finite negative values of the polarization in the order of $5-20\,\%$ are observed over the entire phase space studied. The absolute value of the polarization increases almost linearly with increasing transverse momentum for $p_t>300\,$MeV/c and increases with decreasing rapidity for $y < 0.8$.
- New data on the differential cross section of the dp-elastic scattering at 2.5 GeV obtained with HADES detectorPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.
- Proton induced dielectron radiation off Nb: $P_t$ and $Y$ distributionsPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.Following our recent letter [1] on inclusive e(+)e(−) pair production in proton induced reactions at Ekin = 3.5 GeV on the nucleus Nb, we present here in addition the transverse and rapidity distributions for various e(+)e(−) invariant mass bins and compare them to reference data measured in p+p reactions.
- The dp-elastic cross section measurement at the deuteron kinetic energy of 2.5-GeVPublication . HADES collaboration (98 authors); Blanco, A.; Fonte, P.; Lopes, L.; Mangiarotti, A.New results on the differential cross section in deuteron-proton elastic scattering are obtained at the deuteron kinetic energy of 2.5 GeV with the HADES spectrometer. The angular range of 69deg. - 125deg. in the center of mass system is covered. The obtained results are compared with the relativistic multiple scattering model calculation using the CD-Bonn deuteron wave function. The data at fixed scattering angles in the c.m. are in qualitative agreement with the constituent counting rules prediction.