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Register a new userTensor Ayy and Vector Ay Analyzing Powers of the (d,p) and (d,d) Reactions at 5 Gev/c and 178 MR
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New data on the tensor analyzing power Ayy of the ^9Be(d,p)X reaction at an initial deuteron momentum of 5 GeV/c and secondary particles (protons and deuterons) detection angle of 178 mr have been obtained at the JINR Synchrophasotron. The proton data obtained are analyzed within the framework of an approach based on the light-front dynamics using Karmanovs relativistic deuteron wave function. Contrary to the calculations with standard non-relativistic deuteron wave functions, we have managed to explain the new data within the framework of our approach without invoking degrees of freedom additional to nucleon ones. The ^9Be(d,d)X data are obtained in the vicinity of the excitation of baryonic resonances with masses up to 1.8 GeV/c^2. The Ayy data are in a good agreement with the previous data obtained at 4.5 and 5.5 GeV/c when they are plotted versus $t$. The results of the experiment are compared with the predictions of the plane wave impulse approximation and omega-meson exchange models.
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The angular dependence of the tensor Ayy and vector Ay analyzing powers in the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen and carbon have been measured. The range of measurements corresponds to the baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being in good agreement with the previous results demonstrate an approximate $t$ scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role of the spin-dependent part of the elementary amplitude of the NN->NN* reaction. The results of the experiment are compared with model predictions of the plane-wave impulse approximation.
A complete set of analyzing powers for the dd->3Hp reaction at the kinetic beam energy of 200 MeV has been measured in the full angular range in the c.m. frame. The observed signs of the tensor analyzing powers Ayy, Axx, and Axz at forward and backward directions have clearly demonstrated the sensitivity to the ratio of the D- and S-wave components of the triton and deuteron, respectively. The new high-precision data are compared with the prediction of the relativistic multiple-scattering model by using standard wave functions of the three-nucleon bound state and of the deuteron.
The data on the tensor Ayy, Axx, Axz and vector Ay analyzing powers in the dd->3Hen obtained at Td= 270 MeV in the angular range 0 - 110 degrees in the c.m. are presented. The observed negative sign of the tensor analyzing powers Ayy, Axx and Axz at small angles clearly demonstrate the sensitivity to the ratio of the D and S wave component of the 3He wave function. However, the one-nucleon exchange calculations by using the standard 3He wave functions have failed to reproduce the strong variation of the tensor analyzing powers as a function of the angle in the c.m.
We report measurements of charmed-hadron ($D^{0}$, $D^{*}$) production cross sections at mid-rapidity in $p$ + $p$ collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays $D^{0}rightarrow K^{-}pi^{+}$, $D^{*+}rightarrow D^{0}pi^{+}rightarrow K^{-}pi^{+}pi^{+}$ and their charge conjugates, covering the $p_T$ range of 0.6$-$2.0 GeV/$c$ and 2.0$-$6.0 GeV/$c$ for $D^{0}$ and $D^{*+}$, respectively. From this analysis, the charm-pair production cross section at mid-rapidity is $dsigma/dy|_{y=0}^{cbar{c}}$ = 170 $pm$ 45 (stat.) $^{+38}_{-59}$ (sys.) $mu$b. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a Fixed-Order Next-to-Leading Logarithm calculation.
The finite range adiabatic wave approximation provides a practical method to analyze (d,p) or (p,d) reactions, however until now the level of accuracy obtained in the description of the reaction dynamics has not been determined. In this work, we perform a systematic comparison between the finite range adiabatic wave approximation and the exact Faddeev method. We include studies of $^{11}$Be(p,d)$^{10}$Be(g.s.) at $E_p=$5, 10 and 35 MeV; $^{12}$C(d,p)$^{13}$C(g.s.) at $E_d=$7, 12 and 56 MeV and $^{48}$Ca(d,p)$^{49}$Ca(g.s.) at $E_d=$19, 56 and 100 MeV. Results show that the two methods agree within $approx 5%$ for a range of beam energies ($E_d approx 20-40$ MeV) but differences increase significantly for very low energies and for the highest energies. Our tests show that ADWA agrees best with Faddeev when the angular momentum transfer is small $Delta l=0$ and when the neutron-nucleus system is loosely bound.
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