D(e.e'p)Coincidence Measurement at Threshold Region

D(e.e‘p)反应将在低相对n-p能量和高四动量转移下进行符合测量。在实验中，用麻省理工学院贝茨实验室正在建造的脉冲展宽器发出的高能连续电子束照射液重靶。将测量截面作为质子角度的函数，以确定无干涉O_LO_T和干涉O_LT；LT&GT；研究最简单的由一个质子和一个中子组成的原子核。在理解核结构和反应方面占有特殊的地位。最近，核子以外的自由度尤其吸引了物理学家的注意。在大约10年前的单臂电子散射中，介子交换电流的贡献被清楚地观察到在氚的分裂阈值处。然而，该地区从未进行过巧合实验。计算结果表明，Sigma&lt；LT&Gt；干涉截面对相对论效应非常敏感。我们的建议已经被接受为使用担架环上的连续梁的实验之一。工程已于去年年底竣工，目前正在调试中。我们的试验是在断面较小的地区进行的。这需要精心准备设备。因此，我们选择了一个准弹性散射区的实验作为第一个贡献的实验，这是由美国的几个摸索者提出的。这个实验可以使用目前可用的脉冲光束。它使用极化的电子束，可以获得一个额外的项来提取依赖于电子自旋的特殊项。在实验中，除了一个符合的电子外，还使用了四个光谱仪从散射平面外探测到质子。这项实验将于1996年春进行。

Coincidence measurements will be made for the d (e.e'p) reaction at low relative n-p energy and high four-momentum transfer. In the experiment, a liquid-deuterium target is irradiated with a high-energy continuous electron beam from the pulse-stretcher under construction at MIT-Bates laboratory. Cross sections will be measured as a function of proton angle in order to determine the non-interference o_Lo_T and interference o_<LT> cross sections.Study of the deuteron, the most simple nucleus which consists of one proton and one neutron. occupies a special position to understand nuclear structure and reactions. Recently, degrees of freedom beyond nucleons particularly draw the attension of physisits. The contribution of meson-exchange currents was clearly observed at the break-up threshold of the deuteron in single-arm electron scattering about 10 years ago. Coincidence experiments, however, have never been made in the region. Several calculations shows the sigma_<LT> interference cross section is sensitive to relativistic effects there.A pulse stretcher has been constructed in MIT-Bates laboratory. Our proposal has been accepted as one of experiments using continuous beams from the stretcher ring. The construction was completed at the end of the last year, and it is under commissioning now.Our experiment is made in the region where the cross section is small. It needs carefull preparation of equipments. we chose, therefore, an experiment at the quasi-elastic scattering region as the first experiment to contribute, that has been proposed by several gropes in USA.This experiment is capable with a pulsed beam available now. It uses a polarized electron beam, and an extra term can be obtained to extract a spetial term that depends on the spin of the electron. In the experiment, protons are detected out of the scatterig plane using four spectrometers in addition to a coincided electron. The experiment will be made in the spring of 1996.