Jyotismita Adhikary, Luis A. Anchordoqui, Akitaka Ariga, Tomoko Ariga, Alan J. Barr, Brian Batell, Jianming Bian, Jamie Boyd, Matthew Citron, Albert De Roeck, Milind V. Diwan, Jonathan L. Feng, Christopher S. Hill, Yu Seon Jeong, Felix Kling, Steven Linden, Toni Mäkelä, Kostas Mavrokoridis, Josh McFayden, Hidetoshi Otono, Juan Rojo, Dennis Soldin, Anna Stasto, Sebastian Trojanowski, Matteo Vicenzi, Wenjie Wu
The recent direct detection of neutrinos at the LHC has opened a new window on high-energy particle physics and highlighted the potential of forward physics for groundbreaking discoveries. In the last year, the physics case for forward physics has continued to grow, and there has been extensive work on defining the Forward Physics Facility and its experiments to realize this physics potential in a timely and cost-effective manner. Following a 2-page Executive Summary, we present the status of the FPF, beginning with the FPF's unique potential to shed light on dark matter, new particles, neutrino physics, QCD, and astroparticle physics. We summarize the current designs for the Facility and its experiments, FASER2, FASER$ν$2, FORMOSA, and FLArE, and conclude by discussing international partnerships and organization, and the FPF's schedule, budget, and technical coordination.
Luis A. Anchordoqui, John K. Anders, Akitaka Ariga, Tomoko Ariga, David Asner, Jeremy Atkinson, Alan J. Barr, Larry Bartoszek, Brian Batell, Hans Peter Beck, Florian U. Bernlochner, Bipul Bhuyan, Jianming Bian, Aleksey Bolotnikov, Silas Bosco, Jamie Boyd, Nick Callaghan, Gabriella Carini, Michael Carrigan, Kohei Chinone, Matthew Citron, Isabella Coronado, Peter Denton, Albert De Roeck, Milind V. Diwan, Sergey Dmitrievsky, Radu Dobre, Monica D'Onofrio, Jonathan L. Feng, Max Fieg, Elena Firu, Reinaldo Francener, Haruhi Fujimori, Frank Golf, Yury Gornushkin, Kranti Gunthoti, Claire Gwenlan, Carl Gwilliam, Andrew Haas, Elie Hammou, Daiki Hayakawa, Christopher S. Hill, Dariush Imani, Tomohiro Inada, Sune Jakobsen, Yu Seon Jeong, Kevin J. Kelly, Samantha Kelly, Luke Kennedy, Felix Kling, Umut Kose, Peter Krack, Jinmian Li, Yichen Li, Steven Linden, Ming Liu, Kristin Lohwasser, Adam Lowe, Steven Lowette, Toni Mäkelä, Roshan Mammen Abraham, Christopher Mauger, Konstantinos Mavrokoridis, Josh McFayden, Hiroaki Menjo, Connor Miraval, Keiko Moriyama, Toshiyuki Nakano, Ken Ohashi, Toranosuke Okumura, Hidetoshi Otono, Vittorio Paolone, Saba Parsa, Junle Pei, Michaela Queitsch-Maitland, Mary Hall Reno, Sergio Rescia, Filippo Resnati, Adam Roberts, Juan Rojo, Hiroki Rokujo, Olivier Salin, Jack Sander, Sai Neha Santpur, Osamu Sato, Paola Scampoli, Ryan Schmitz, Matthias Schott, Anna Sfyrla, Dennis Soldin, Albert Sotnikov, Anna Stasto, George Stavrakis, Jacob Steenis, David Stuart, Juan Salvador Tafoya Vargas, Yosuke Takubo, Simon Thor, Sebastian Trojanowski, Yu Dai Tsai, Serhan Tufanli, Svetlana Vasina, Matteo Vicenzi, Iacopo Vivarelli, Nenad Vranjes, Marija Vranjes Milosavljevic, Kazuhiro Watanabe, Michele Weber, Benjamin Wilson, Wenjie Wu, Tiepolo Wybouw, Kin Yip, Jaehyeok Yoo, Jonghee Yoo
The Forward Physics Facility (FPF) is a proposed extension of the HL-LHC program designed to exploit the unique scientific opportunities offered by the intense flux of high energy neutrinos, and possibly new particles, in the far-forward direction. Located in a well-shielded cavern 627 m downstream of one of the LHC interaction points, the facility will support a broad and ambitious physics program that significantly expands the discovery potential of the HL-LHC. Equipped with four complementary detectors -- FLArE, FASER$ν$2, FASER2, and FORMOSA -- the FPF will enable breakthrough measurements that will advance our understanding of neutrino physics, quantum chromodynamics, and astroparticle physics, and will search for dark matter and other new particles. With this Letter of Intent, we propose the construction of the FPF cavern and the construction, integration, and installation of its experiments. We summarize the physics case, the facility design, the layout and components of the detectors, as well as the envisioned collaboration structure, cost estimate, and implementation timeline.
Yichen Li, Aleksey Bolotnikov, Milind Diwan, Jay Hyun Jo, Steven Kettell, Steven Linden, Xin Qian, Matteo Vicenzi, Chao Zhang
We describe the design and performance of a 260-liter liquid argon (LAr) cryogenic test stand for liquid argon detector research and development at BNL. The system uses gas-phase argon purification with continuous pump-free circulation, in which boil-off argon gas is purified, recondensed, and returned to the cryostat by gravity without a mechanical recirculation pump; it also incorporates an upgraded condenser that increases the effective thermal contact area by a factor of 13 relative to the previously developed 20-liter system reported perviously. A liquid argon purity monitor is installed to measure the electron lifetime directly in LAr, enabling quantitative characterization of charge attenuation due to electronegative impurities. Under the operating conditions reported here, the demonstrated electron lifetime is 0.5 ms. The system is designed to enable rapid iteration of detector components in complete operational cycles, including pump-down, leak verification, cryogenic fill, stable operation, and warm-up, which can be completed within 7 days. Such a fast turnaround time, together with the medium-scale liquid volume and direct purity diagnostics, makes the facility well suited for testing and refining detector designs in support of large liquid argon time projection chamber (LArTPC) experiments.
Luis A. Anchordoqui, Akitaka Ariga, Tomoko Ariga, Alan J. Barr, Brian Batell, Jianming Bian, Jamie Boyd, Matthew Citron, Albert De Roeck, Milind V. Diwan, Jonathan L. Feng, Christopher S. Hill, Felix Kling, Steven Linden, Toni Mäkelä, Kostas Mavrokoridis, Josh McFayden, Hidetoshi Otono, Juan Rojo, Dennis Soldin, Anna Stasto, Sebastian Trojanowski, Matteo Vicenzi, Wenjie Wu
The Forward Physics Facility (FPF) is a proposal developed to exploit the unique scientific potential made possible by the intense hadron beams produced in the far-forward direction at the high luminosity LHC (HL-LHC). Housed in a well-shielded cavern 627 m from the LHC interactions, the facility will enable a broad and deep scientific programme which will greatly extend the physics capability of the HL-LHC. Instrumented with a suite of four complementary detectors -- FLArE, FASER$ν$2, FASER2 and FORMOSA -- the FPF has unique potential to shed light on neutrino physics, QCD, astroparticle physics, and to search for dark matter and other new particles. This contribution describes some of the key scientific drivers for the facility, the engineering and technical studies that have been made in preparation for it, the design of its four complementary experiments, and the status of the project's partnerships and planning.
Babak Azmoun, Aleksey Bolotnikov, Francesca Capocasa, Milind Diwan, Yimin Hu, Jay Hyun Jo, William Lenz, Yichen Li, Abdul Rumaiz, Vyara Tsvetkova, Matteo Vicenzi
The Deep Underground Neutrino Experiment (DUNE) Phase-II Far Detector is considering an approximately 2000\,m$^2$ photon detection system to achieve a target mean light yield of 180\,PE/MeV. Meeting this requirement demands scalable, cost-effective, and high-quality wavelength-shifter (WLS) coatings capable of converting 127\,nm liquid-argon scintillation light into visible photons with controlled and reproducible optical performance. We report on the successful realization of an industrial physical vapor deposition (PVD) process for \textit{p}-terphenyl (pTP) coatings, adapted from vacuum deposition techniques developed for OLED display manufacturing, to produce uniform WLS layers on large-area inorganic substrates, a task traditionally challenged by adhesion and uniformity issues at organic--inorganic interfaces. Surface characterization by profilometry and spectroscopic measurements demonstrates edge-region thickness variation below 10\% and emission spectra consistent with high-quality pTP reference samples. The industrial process demonstrates reproducibility, scalability, and significantly reduced production time compared to laboratory-based methods, while maintaining optical characteristics consistent with established pTP reference samples. These results establish a viable pathway for mass production of high-performance pTP coatings for DUNE FD3 and future neutrino experiments, from a coating manufacturing and process standpoint. Detector-level performance validation, including quantitative VUV conversion efficiency measurements at 127\,nm, is identified as future work.