Homework 4

1) By using the Infinite Momentum Frame (IMF) technique discussed in class, demonstrate that the matrix element modulus squared for radiation of a gluon by a quark is:

$$\mid M_{l \rightarrow k l^\prime} \mid^2 = \frac{1}{2} g^2 C... ...\perp^2}{z} + \frac{2 l_\perp^2}{l_\perp^2 + (1-z)^2} \right]$$

2) What approximation is needed in the equation above in order to obtain the splitting function:

$$P_{qq} = C_F \frac{1+z^2}{1-z}$$

3) Draw all the (distinct) radiation processes that can occur at leading order in the DIS reaction, besides the gluon radiation discussed in class.