HPQCD Collaboration

HPQCD Collaboration
Name	HPQCD Collaboration
Formation	1990s
Focus	Lattice Quantum Chromodynamics
Members	international group of physicists
Headquarters	distributed

HPQCD Collaboration The HPQCD Collaboration is an international consortium of theoretical physicists specializing in lattice calculations for Quantum Chromodynamics and related problems in High energy physics. Founded by researchers with affiliations at institutions such as University of Glasgow, University of Cambridge, Fermilab, and University of Edinburgh, the group combines expertise from laboratories and universities like CERN, DESY, Brookhaven National Laboratory, and Massachusetts Institute of Technology. HPQCD's work interfaces with experimental programs at facilities including Large Hadron Collider, Belle II, LHCb, BaBar, and CLEO.

History

The collaboration emerged in the 1990s amid advances at institutions such as Fermilab, Brookhaven National Laboratory, CERN, DESY, and Rutherford Appleton Laboratory, building on earlier lattice efforts by researchers associated with UK Science and Technology Facilities Council and US groups at Brookhaven National Laboratory and Los Alamos National Laboratory. Early members included academics with appointments at University of Glasgow, University of Cambridge, University of Edinburgh, and University of Liverpool, who coordinated with experimentalists at CLEO and BaBar to address heavy-quark phenomenology. Over time the collaboration expanded links to research centers like Argonne National Laboratory, Lawrence Berkeley National Laboratory, Stanford University, and University of Washington, integrating techniques from teams led by figures associated with Riken and RIKEN-BNL Research Center.

Research Focus and Methods

HPQCD concentrates on high-precision determinations in Quantum Chromodynamics relevant to flavor physics, electroweak tests, and hadron structure, emphasizing quantities measured at experiments such as LHCb, Belle II, BaBar, CMS, and ATLAS. Core topics include decay constants, form factors, quark masses, and strong coupling constants connected to studies at Large Hadron Collider, Tevatron, BaBar, and CLEO. Methodologically the group employs lattice gauge theory techniques developed alongside methodology from teams at MILC Collaboration, RBC-UKQCD, ETM Collaboration, and CLS while leveraging algorithms originating in work at IBM Research, Google Quantum AI, and national laboratories. They apply perturbative matching with inputs related to calculations from Particle Data Group compilations and theoretical frameworks influenced by work at SLAC National Accelerator Laboratory and Perimeter Institute.

Key Results and Publications

HPQCD produced precision results for the b-quark mass, c-quark mass, and the strong coupling constant αs that informed global averages by the Particle Data Group, with papers coauthored by investigators affiliated with University of Cambridge, University of Glasgow, Fermilab, DESY, and Brookhaven National Laboratory. Landmark publications addressed B-meson decay constants used by collaborations like LHCb and Belle II, and semileptonic form factors crucial to determinations of CKM matrix elements such as |V_cb| and |V_ub|, influencing analyses by groups at CERN and SLAC. Other influential results included contributions to the theoretical prediction of the muon anomalous magnetic moment compared against measurements from Muon g-2 experiments at Fermilab and BNL, and lattice inputs relevant to searches for physics beyond the Standard Model pursued by collaborations at LHC experiments like ATLAS and CMS.

Collaborations and Partnerships

HPQCD has longstanding interactions with lattice consortia including MILC Collaboration, RBC-UKQCD, ETM Collaboration, and JLQCD, and engages with experimental groups such as LHCb, Belle II, BaBar, and CLEO to provide theoretical inputs. The consortium collaborates with computational centers and funding bodies like DiRAC, USQCD Collaboration, STFC, DOE Office of Science, and EPSRC, while maintaining links to national laboratories including Fermilab, Brookhaven National Laboratory, Lawrence Berkeley National Laboratory, and Argonne National Laboratory. These partnerships extend to academic departments at University of Cambridge, University of Glasgow, University of Edinburgh, University of Southampton, and University of Liverpool.

Computational Resources and Techniques

HPQCD relies on high-performance computing resources such as national supercomputers hosted by DiRAC, systems at Argonne National Laboratory, Lawrence Berkeley National Laboratory, and clusters funded by EPSRC and DOE Office of Science. The collaboration implements improved lattice actions and staggered fermion formalisms developed in concert with the MILC Collaboration and integrates solvers and multigrid algorithms originating from projects at NVIDIA Research, IBM Research, and academic groups at University of Edinburgh and University of Cambridge. Software ecosystems used include community tools developed alongside USQCD Collaboration and code parallels written for architectures promoted by HPE and Cray.

Impact on Particle Physics and Legacy

HPQCD's precise lattice determinations have shaped global fits of CKM matrix unitarity tests employed by collaborations like UTfit and CKMfitter, informing searches for new phenomena pursued at Large Hadron Collider experiments ATLAS and CMS as well as flavor programs at Belle II and LHCb. Its high-precision quark masses and αs inputs influence theoretical predictions referenced by the Particle Data Group and underpin phenomenology in studies conducted at SLAC National Accelerator Laboratory and CERN. The collaboration's methodological advances in lattice actions, error analysis, and code parallelization continue to be adopted by consortia such as RBC-UKQCD and ETM Collaboration, leaving a legacy evident across theoretical and experimental high-energy physics communities.

Category:Lattice quantum chromodynamics Category:Particle physics collaborations