Participant support costs for NSCI SI2-SSE: The N-jettiness software framework for precision perturbative QCD calculations in particle and nuclear physics

Overview: The primary goal of this proposal is the development and deployment of codes incorpo- rating the N-jettiness subtraction approach to perturbative QCD calculations in order to address the ever-increasing precision needs of collider experiments in particle and nuclear physics. This theoretical framework very effectively uses previous community investments in software development by extending publicly-available next-to-leading-order (NLO) codes to next-to-next-to-leading order (NNLO), where the expansion parameter is the strong coupling constant. This advance improves their achievable theoretical precision by an order of magnitude, while maintaining the interface familiar to the user community. The specifi�c objectives of this proposal are as follows: the public release of NNLO corrections for jet production processes at the LHC into a public simulation code that is both fast and user-friendly; the expansion of the functionality of DISTRESS, a new code designed for precision simulations for RHIC and a future electron-ion-collider; the preparation of these precision simulation tools for future multi-core computing architectures that feature smaller memory per core. The N-jettiness subtraction approach is optimized for the massively-parallel computing architectures in which the United States government has invested heavily, and therefore advances the goals of the National Strategic Computing Initiative. Intellectual merit: Both the P5 panel that outlines the plans for high energy physics, and the Nuclear Sci- ence Advisory Committee that recommends future investments in nuclear physics, have emphasized the need for precision theory to advance the state of knowledge in these fi�elds. Achieving the requisite NNLO precision for the perturbative calculations needed to achieve these goals is an enormous computational challenge. The N-jettiness subtraction method can meet this challenge and enable many goals of both the particle and nuclear physics fi�elds to be met. This proposal will advance the precision comparison of theory with experiment through robust, user-friendly software incorporating this powerful new theoretical advance. Broader impacts: A goal of this proposal is to bring the knowledge and potential of HPC to more domain scientists working on precision QCD theory. The use of HPC has the potential to revolutionize the ability to predict with enough precision to match the exquisite data of modern collider experiments, and should become part of the standard research infrastructure of this �field. This will be accomplished through a series of dedicated workshops bringing together domain scientists and computational experts. Additional investigations into increasing community access in these �fields to HPC will be undertaken, including dedicated HPC training for theory students and postdocs. A long-term vision that this proposal hopes to advance is the establishment of a vibrant partnership between domain scientists interested in perturbative QCD applied to collider physics and experts in advanced computing.