The positivity technique and low-lying zeros of Dirichlet $L$-functions

Assuming the generalized Riemann hypothesis, we rediscover and sharpen some of the best known results regarding the distribution of low-lying zeros of Dirichlet $L$-functions. This builds upon earlier work of Omar, which relies on the classical positivity technique of explicit formulas. In addition, we generalize some of our results to a larger class of $L$-functions and provide effective conditional estimates for the lowest zeros of Dirichlet $L$-functions.