  The quest to understand the fundamental building blocks of nature and their
interactions is one of the oldest and most ambitious of human scientific
endeavors. Facilities such as CERN's Large Hadron Collider (LHC) represent a
huge step forward in this quest. The discovery of the Higgs boson, the
observation of exceedingly rare decays of B mesons, and stringent constraints
on many viable theories of physics beyond the Standard Model (SM) demonstrate
the great scientific value of the LHC physics program. The next phase of this
global scientific project will be the High-Luminosity LHC (HL-LHC) which will
collect data starting circa 2026 and continue into the 2030's. The primary
science goal is to search for physics beyond the SM and, should it be
discovered, to study its details and implications. During the HL-LHC era, the
ATLAS and CMS experiments will record circa 10 times as much data from 100
times as many collisions as in LHC Run 1. The NSF and the DOE are planning
large investments in detector upgrades so the HL-LHC can operate in this
high-rate environment. A commensurate investment in R&D for the software for
acquiring, managing, processing and analyzing HL-LHC data will be critical to
maximize the return-on-investment in the upgraded accelerator and detectors.
The strategic plan presented in this report is the result of a
conceptualization process carried out to explore how a potential Scientific
Software Innovation Institute (S2I2) for High Energy Physics (HEP) can play a
key role in meeting HL-LHC challenges.
