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In 2020-2022, extensive discussions and deliberations have taken place in corresponding topical working groups of the Snowmass Accelerator Frontier (AF) and in numerous joint meetings with other Frontiers, Snowmass-wide meetings, a series of Colloquium-style Agoras, cross-Frontier Forums on muon and electron-positron colliders and the collider Implementation Task Force (ITF). The outcomes of these activities are summarized in this Accelerator Frontier report., contribution to Snowmass'21, v.2 (final)

Background: Esophagectomy traditionally has high levels of perioperative morbidity and mortality due to the surgical techniques and case complexity. While thoracic epidural analgesia (TEA) is considered first-line for postoperative analgesia after esophagectomy, there can be complications related to its sympathectomy and mobility impairment. Additionally, it has been shown that postoperative outcomes are improved with early extubation following esophagectomy. Our aim is to describe the impact of transversus abdominus plane (TAP) blocks on extubation rates following esophagectomy when uncoupled from TEA. Methods: This is a retrospective study of 42 patients who underwent trans-hiatal esophagectomy between 2019 and 2022 who received a TAP block in the absence of TEA. The primary outcomes of interest were the rates of extubation within the operating room (OR) and reintubation. Secondary outcomes included: intensive care unit (ICU) and hospital length of stay (LOS), opioid pain medication use, time to enteral diet, reported postoperative pain scores, development of anastomotic leak, and 30-day readmission. Results: The mean age at operation was 63 years and 97.6% of patients were represented by American Society of Anesthesia (ASA) physical status class III or IV. 35 (83.3%) patients immediately extubated postoperatively. Nine patients (21.4%) underwent reintubation during their hospital course. Only six patients (14%) required vasopressors postoperatively. The median LOS was five days in the ICU and 10 days in the hospital. TAP block alone was found to be equivalent to TAP with additional regional blocks (TAP+) on the basis of immediate extubation, reintubation, ICU and hospital LOS, and reported postoperative pain. Conclusion: The results of this study demonstrate TAP blocks do provide comparable rates of successful immediate extubation and reintubation to TEA with fewer hypotensive complications after trans-hiatal esophagectomy. This was shown despite the elevated comorbidity burden of this study’s population. Additionally, TAP blocks maintained similar reported pain control scores to TEA literature.Overall, this study supports the use of TAP blocks as the primary analgesia in patients undergoing trans-hiatal esophagectomy over TEA. Trial Registration: This study includes participants who were retrospectively registered. IRB# 037.HPB.2018.R

The acceleration and storage of high energy polarized proton beams has made tremendous progress over the last 40 years challenging along the way the technologies, precision and the understanding of the beam dynamics of accelerators. This progress is most evident in that one can now contemplate high energy colliders with polarized beams and high luminosity at the same time. After a brief summary of the development and history of polarized proton beam acceleration this chapter will focus on the acceleration of polarized proton beams from MeV to the 100s of GeVs and the possibility of accelerating polarized beams to even higher energies in the future. Elements of the history of polarized electron beams, subject to the effects of synchrotron radiation, will be found in the electron beam polarization dedicated chapters in these lectures.

We discuss the goals, the designs, the state of technical readiness, and the critical R&D needs of the accelerators that are currently under discussion as Higgs and electroweak factories. We also address the respective staging options enabling future energy-frontier colliders. The accelerators covered are based on many different techniques and approaches. They include several circular colliders, various linear colliders, colliders based on energy recovery linacs (ERLs), ERL-ring combinations, as well as gamma-gamma colliders. The linear colliders proposed consist of options for the International Linear Collider (ILC), for the Compact Linear Collider (CLIC), for the Cold Copper Collider (C^3), and for the more recent Higgs-Energy Lepton Collider (HELEN). ERLs are key components of the Recycling Linear e+e- Collider (ReLiC), of the Energy Recovery Linear Collider (ERLC), and of the Circular Energy Recovery Collider (CERC). Among the more conventional ring colliders, the following proposals are featured: the Future Circular Collider (FCC-ee), the Circular Electron Positron Collider (CEPC), the Electron Positron Circular Collider at Fermilab (EPCCF), and the Large Electron Positron collider $\#$3 (LEP-3). In addition, we consider the X-ray FEL based gamma-gamma Collider Higgs Factory (XCC) and the High-Energy High-Luminosity gamma-gamma collider (HE&HL gamma-gamma). Finally, a Higgs factory based on a circular muon collider is mentioned for completeness., Submitted to Snowmass 2021

Colliders are essential research tools for particle physics. Numerous future collider proposal were discussed in the course of the US high energy physics community strategic planning exercise Snowmass'21. The Implementation Task Force (ITF) has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This article describes the metrics and approaches, and presents evaluations of future colliders performed by the ITF.

The Snowmass 2021 Implementation Task Force has been established to evaluate the proposed future accelerator projects for performance, technology readiness, schedule, cost, and environmental impact. Corresponding metrics has been developed for uniform comparison of the proposals ranging from Higgs/EW factories to multi-TeV lepton, hadron and ep collider facilities, based on traditional and advanced acceleration technologies. This report documents the metrics and processes, and presents evaluations of future colliders performed by Implementation Task Force., Comment: 68 pages; Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021)