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Data

 

The spin-observables presented in this section were extracted from the quasifree scattering data taken during experiments E385 and E387. The quasifree region was split into 10 MeV bins which seemed to provide reasonable statistics to extract the observables while still providing a good picture of the energy dependence. The results from the data taken with the normally polarized beam, which includes , , and P (induced polarization), are listed on tables gif and gif for and , respectively.

  
Table: Spin-observable results from the reaction at for an polarized proton beam with MeV.

  
Table: Spin-observable results from the reaction at for an polarized proton beam with MeV.

These results are shown in graphical format in figure gif compared to results from recent Faddeev type calculations [Wit96] of the deuterium observables. The analyzing power and induced polarization seem to be in reasonable agreement. Both show rather small magnitudes. However, in there is significant disagreement between the data and both the Faddeev calculations and the data.

  
Figure: Spin-observable results from the and reactions at for an polarized proton beam with MeV. The excitation spectra are shown at the top. The dashed line show the results of Faddeev calculations of the spin-observables for the deuterium reaction. The vertical dotted line indicate the energy loss for free np scattering.

The results for the sideways and longitudinal incident beams for the reaction are compiled in tables gif and gif, respectively. Similarly, the spin-observables from the are shown in tables gif and gif for the sideways and longitudinally polarized beams, respectively.

  
Table: Spin-observable results from the reaction at for an polarized proton beam with MeV.

  
Table: Spin-observable results from the reaction at for an polarized proton beam with MeV.

  
Table: Spin-observable results from the reaction at for an polarized proton beam with MeV.

  
Table: Spin-observable results from the reaction at for an polarized proton beam with MeV.

The results from the sideways and longitudinal data are also shown in figures gif and gif, respectively. Generally, it seems that the Faddeev calculations predict the results fairly well for all the in-plane spin observables with possible exception of . The and results also seem to follow the same trends.

  
Figure: Spin-observable results from the and reactions at for an polarized proton beam with MeV. The excitation spectra are shown at the top. The dashed line show the results of Faddeev calculations of the spin-observables for the deuterium reaction. The vertical dotted line indicate the energy loss for free np scattering.

  
Figure: Spin-observable results from the and reactions at for an polarized proton beam with MeV. The excitation spectra are shown at the top. The dashed line show the results of Faddeev calculations of the spin-observables for the deuterium reaction. The vertical dotted line indicate the energy loss for free np scattering.

The center-of-mass spin observables, 's, are shown in figures gif and gif. These results are also compared to the results of Faddeev calculations (shown with the dashed line).

  
Figure: (spin 0) and (spin transverse, ) spin observables as a function of energy loss at . Results from both deuterium and carbon are shown. The short-dashed line are the results of Faddeev calculations of the deuterium spin observables. The long-dashed line shows the free np scattering results based on the Argonne potential. The vertical dotted line indicates the energy loss for free np scattering.

  
Figure: (spin longitudinal, ) and (spin transverse, ) spin observables as a function of energy loss at . Results from both deuterium and carbon are shown. The short-dashed line are the results of Faddeev calculations of the deuterium spin observables. The long-dashed line shows the free np scattering results based on the Argonne potential. The vertical dotted line indicates the energy loss for free np scattering.

The results have been presented for completeness but it is unclear if any conclusions regarding quasifree scattering can be drawn from them. The range of energy loss over which data was gathered, as shown at the top of figure gif for example, spans a momentum transfer of fm to fm. In this range quasifree scattering is just beginning to turn on. That is, the momentum transferred to the stationary nucleon in the nucleus is barely sufficient for knock-out, which defines quasifree scattering. Also, in this region of momentum transfer measured at the pion effects are going to be very small. From figure gif one can see that the expected longitudinal contribution from the pion is around zero. This supported by the fact that the longitudinal spin observable is essentially zero in figure gif. To look for a change in nuclear response functions due to an enhanced pion field it is reasonable to look other momentum transfers where the pion residual interaction in non-zero.

It is worth mentioning at this point that data were taken at primarily because was considered to be a possibly interesting angle. That meant that the INPOL detector had to gather data while the KSU detector gathered data at .



next up previous contents
Next: Data Up: RESULTS Previous: Beam Polarization



Michael A. Lisa
Tue Apr 1 08:52:10 EST 1997