# Kronecker delta integrale

1. Jan 25, 2014

### Safinaz

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Jan 25, 2014

### Safinaz

Hi all,

How to know the value of kronecker delta integrale $\int \delta(m_h-2E) dE$ ?

Best,
S.

3. Jan 25, 2014

### vanhees71

It doesn't make sense to have a Kronecker $\delta$ in this integral. Isn't this rather a Dirac $\delta$ distribution?

If so, you may use the formula
$$\int_{\mathbb{R}} \mathrm{d} x \delta[f(x)] g(x)=\sum_{j} \frac{1}{\left |f'(x_j) \right|} g(x_j),$$
where $f$ is a function that has only 1st order roots $x_j$.