Elwhiter samples: dark scalar samples for more masses and lifetimes

I add decfiles to generate some MC for the decay B^+ \to K^+ \chi, \chi \to K^+ K^- and B^+ \to K^+ \chi, \chi \to \pi^+ \pi^- for a range of \chi masses and lifetimes. This Monte Carlo is needed for the ongoing analysis searching for a dark scalar \chi in this decay channel. For the analysis we need to study for both the KK and pipi mode how the dark scalar mass resolution varies as a function of dark scalar mass hence the need to request for masses which span a set of points across the dihadron mass range from the dipion threshodl up to the difference between the B and kaon mass. Some samples already exist but currently we don’t have enough masses to cover the space well. Also a range of lifetimes is required to study how this affects the geometric acceptance.

Note the event numbers have been choosen as best possible given the limited event numbers left available.