@article{c449051dd736480fae2fbd223334d287,
title = "Variational study of two-nucleon systems with lattice QCD",
abstract = "The low-energy spectrum and scattering of two-nucleon systems are studied with lattice quantum chromodynamics using a variational approach. A wide range of interpolating operators are used: dibaryon operators built from products of plane-wave nucleons, hexaquark operators built from six localized quarks, and quasilocal operators inspired by two-nucleon bound-state wave functions in low-energy effective theories. Sparsening techniques are used to compute the timeslice-to-all quark propagators required to form correlation-function matrices using products of these operators. Projection of these matrices onto irreducible representations of the cubic group, including spin-orbit coupling, is detailed. Variational methods are applied to constrain the low-energy spectra of two-nucleon systems in a single finite volume with quark masses corresponding to a pion mass of 806 MeV. Results for S- and D-wave phase shifts in the isospin singlet and triplet channels are obtained under the assumption that partial-wave mixing is negligible. Tests of interpolating-operator dependence are used to investigate the reliability of the energy spectra obtained and highlight both the strengths and weaknesses of variational methods. These studies and comparisons to previous studies using the same gauge-field ensemble demonstrate that interpolating-operator dependence can lead to significant effects on the two-nucleon energy spectra obtained using both variational and nonvariational methods, including missing energy levels and other discrepancies. While this study is inconclusive regarding the presence of two-nucleon bound states at this quark mass, it provides robust upper bounds on two-nucleon energy levels that can be improved in future calculations using additional interpolating operators and is therefore a step toward reliable nuclear spectroscopy from the underlying Standard Model of particle physics.",
author = "Saman Amarasinghe and Riyadh Baghdadi and Zohreh Davoudi and William Detmold and Marc Illa and Assumpta Parre{\~n}o and Pochinsky, {Andrew V.} and Shanahan, {Phiala E.} and Wagman, {Michael L.}",
note = "Funding Information: We are grateful to Silas Beane, Kostas Orginos, and Martin Savage for extensive discussions. We especially thank Kostas Orginos for his role in generating the gauge-field ensemble used in this work. We further thank Martin Savage for collaboration in the early stages of this work and for use of the University of Washington Hyak computational infrastructure to perform some parts of the calculations that are presented. We acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing HPC resources on Frontera that have contributed to the research results reported within this paper (). This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (RES-FI-2022-1-0040). Computations of this work were carried out using the c hroma , q lua , quda , and t iramisu software libraries. A. S. is supported in part by DARPA under Grants No. HR0011-18- 3-0007 and No. HR0011-20-9-0017. Z. D. is supported by the Alfred P. Sloan fellowship and by the Maryland Center for Fundamental Physics at the University of Maryland, College Park. She further acknowledges support from the RIKEN Center for Accelerator-based Sciences with which she was affiliated during earlier stages of this work. W. D. and P. E. S. are supported in part by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under a grant contract. W. D. and A. V. P. are supported in part by the SciDAC4 Grant No. DE-SC0018121. W. D. is also supported within the framework of the TMD Topical Collaboration of the U.S. Department of Energy, Office of Science, Office of Nuclear Physics. P. E. S. is additionally supported by the National Science Foundation under EAGER Grant No. 2035015, by the U.S. DOE Early Career Award No. DE-SC0021006, by a NEC research award, and by the Carl G and Shirley Sontheimer Research Fund. W. D. and P. E. S. are supported by the National Science Foundation under Cooperative Agreement PHY-2019786 (The NSF AI Institute for Artificial Intelligence and Fundamental Interactions, ). M. I. is supported by the Universitat de Barcelona through the scholarship APIF. M. I. and A. P. acknowledge financial support from MCIN/AEI/10.13039/501100011033 (Grants CEX2019-000918-M and PID2020-118758GB-I00), from the European FEDER funds under Contract No. FIS2017-87534-P, and from the EU STRONG-2020 project under the program H2020-INFRAIA-2018-1, Grant Agreement No. 824093. This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. Publisher Copyright: {\textcopyright} 2023 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the {"}https://creativecommons.org/licenses/by/4.0/{"}Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.",
year = "2023",
month = may,
day = "1",
doi = "10.1103/PhysRevD.107.094508",
language = "English (US)",
volume = "107",
journal = "Physical Review D",
issn = "2470-0010",
publisher = "American Physical Society",
number = "9",
}