The Q -value of a nuclear reaction and kinetic energy of the projectile particle, K p are related as

The Q-value of the reaction is defined as the difference between the sum of the masses of the initial reactants and the sum of the masses of the final products, in energy units.

For any reaction to happen spontaneously there must be some energy released in the process. Therefore,

$\left(K_p+Q\right)>0$.