题目如图1所示,在匀强磁场中附加另一匀强磁场,附加磁场位于图中阴影区域,附加磁场区域的对称轴OO′与SS′垂直.a、b、c三个质子先后从S点沿垂直于磁场的方向射入磁场,它们的速度大小相等,b的速度方向与SS′垂直,a、c的速度方向与b的速度方向间的夹角分别为α、β,且α>β.三个质子经过附加磁场区域后能到达同一点S′,则下列说法中正确的有 The subject is shown in Fig.1, where another uniform magnetic field is added to the uniform magnetic field, the additional magnetic field is located in the shaded area in the figure, and the symmetry axis OO 'of the additional magnetic field is perpendicular to SS'. The three protons a, b, S points are perpendicular to the magnetic field into the magnetic field direction, the speed of their equal size, b speed direction and SS 'vertical, a, c and b of the speed direction of the direction of the angle between the angles were α, β, and α > β three protons through the additional magnetic field to reach the same point S ', then the following statement is correct