Spin-dependent exotic interactions
Precision tests of fundamental symmetries · ECT*, Trento, Italy.
Meeting details →
Beyond the Standard Model
A shared platform for spin-dependent forces beyond the Standard Model.
Explore experimental limits, follow the research landscape, and connect with the people advancing exotic-interaction searches.
Exotic-boson-mediated interactionRMP 97, 025005
285Curated datasets
9Coupling types
10−19–1014 mInteraction range
Open Community resource
Interactive analysis
Compare constraints in one consistent framework.
Move from a global view of the field to individual experiments, then bring your own result into the same parameter space.
Notation and operator definitions follow the field review in Reviews of Modern Physics. Read the RMP review →
Interactive Limit Explorer
Select a coupling group, inspect published bounds, and compare a new result without rebuilding the plotting pipeline.
- Overlay and highlight individual constraints
- Filter by dataset or experimental system
- Upload a two-column dataset for comparison
Open research infrastructure
Built for people, software, and automated scientific workflows.
SD5thF is more than a collection of downloadable curves. Its versioned, machine-readable records connect numerical constraints to interaction potentials, fermion pairs, experimental methods, and primary literature.
Versioned APIStable v1 endpoints for programmatic access
Linked metadataMethods, publications, DOI links, and review context
Reproducible reuseStructured records for analysis tools and automated agents
Research landscape
Enter the field from different perspectives.
Browse the same body of constraints by theoretical interaction, fermion pair, or experimental approach. Throughout this platform, spin-dependent fifth forces refer to the broader class of phenomena also known as spin-dependent exotic interactions.
01 / THEORY
Interaction categories
Axial, vector, scalar, pseudoscalar, tensor, and pseudotensor coupling structures.
↗ 02 / PARTICLESFermion pairs
Navigate constraints across lepton–lepton, lepton–nucleon, and nucleon–nucleon systems.
↗ 03 / METHODSExperimental systems
Connect bounds to spectroscopy, spin sensors, macroscopic searches, and astrophysical probes.
↗ 04 / TRANSLATIONSCoupling relations
Translate SD5thF couplings into effective energy scales and axion or ALP conventions.
↗Community & exchange
Where the field meets, learns, and grows.
Discover focused meetings, research openings, fellowships, and learning resources across precision measurement and new-physics searches.
Open research positions
Master’s, PhD, and postdoctoral opportunities in precision measurement, quantum sensing, and fundamental physics.
View openings →Quest of New Physics at the Precision Frontier
WE-Heraeus Seminar · PTB Berlin, Germany
Meeting details ↗Contribute to SD5thF
Growing through shared data and community participation.
Send us a new result, correction, meeting, position, fellowship, or learning resource. Lei Cong and Dmitry Budker will review the information for the next update.
Reproducible research
Download, cite, contribute.
Use the normalized dataset, cite a versioned record, or contribute a new published constraint to the community collection.
Cong, L., Ji, W. & Budker, D. (2024). Fifth Force Limits. Zenodo. https://doi.org/10.5281/zenodo.14572652