Title: Cascade production (dramatically) improves beam dump sensitivities to long-lived particles

Abstract: High intensity beam dumps offer some of the strongest constraints on long-lived particles for masses below a few GeV.  Sensitivity projections and exclusion limits are often computed in a conservative “primary only” approximation where only the flux generated by the beam’s primary interactions are included.  In this talk I will explain how to systematically include production that is initiated by electromagnetic cascades in the material, and their impact on long-lived particle searches. In certain regions of parameter space, sensitivity (at the level of the event rate) can be enhanced by four orders of magnitude.  I will explain the source of this enhancement and comment on implications for future searches at accelerator facilities. 

https://lbnl.zoom.us/j/94928022788?pwd=emVQWG1mTnhSbHVqekVuenk0VEVQZz09