ﻻ يوجد ملخص باللغة العربية
The tagged quasi-free $np to nppi^+pi^-$ reaction has been studied experimentally with the High Acceptance Di-Electron Spectrometer (HADES) at GSI at a deuteron incident beam energy of 1.25 GeV/nucleon ($sqrt s sim$ 2.42 GeV/c for the quasi-free collision). For the first time, differential distributions for $pi^{+}pi^{-}$ production in $np$ collisions have been collected in the region corresponding to the large transverse momenta of the secondary particles. The invariant mass and angular distributions for the $nprightarrow nppi^{+}pi^{-}$ reaction are compared with different models. This comparison confirms the dominance of the $t$-channel with $DeltaDelta$ contribution. It also validates the changes previously introduced in the Valencia model to describe two-pion production data in other isospin channels, although some deviations are observed, especially for the $pi^{+}pi^{-}$ invariant mass spectrum. The extracted total cross section is also in much better agreement with this model. Our new measurement puts useful constraints for the existence of the conjectured dibaryon resonance at mass M$sim$ 2.38 GeV and with width $Gammasim$ 70 MeV.
The transverse spin correlations A_{x,x} and A_{y,y} have been measured in the pol{d} pol{p} -> p_spec {pp}_s pi- reaction at COSY-ANKE at 353 MeV per nucleon. Here {pp}_s denotes a proton-proton pair with low excitation energy, which is dominantly i
The transverse spin correlations Axx and Ayy in the np-> d pi^0 reaction have been measured for the first time in quasi-free kinematics at the COSY-ANKE facility using a polarised deuteron beam incident on a polarised hydrogen cell target. The result
In pp collisions at 1.25 GeV kinetic energy, the HADES collaboration aimed at investigating the di-electron production related to $Delta$ (1232) Dalitz decay ($Delta^+ to pe^+e^-$). In order to constrain the models predicting the cross section and th
We report on the investigation of dielectron production in tagged quasi-free neutron-proton collisions by using a deuteron beam of kinetic energy 1.25 GeV/u inpinging on a liquid hydrogen target. Our measurements with HADES confirm a significant exce
Differential cross-sections for quasi-free $pi^0$ photoproduction from the proton and neutron bound in the deuteron have been measured for $E_gamma= 200 - 400$ MeV at $theta^{rm lab}_gamma = 136.2^circ$ usind the Glasgow photon tagger at MAMI, the Ma