Proton Size Anomaly

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.106.153001· OSTI ID:21550298

Barger, Vernon ^[1]; Chiang, Cheng-Wei ^[2]; Keung, Wai-Yee ^[3]; Marfatia, Danny ^[4]

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1. Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
2. Department of Physics and Center for Mathematics and Theoretical Physics, National Central University, Chungli, Taiwan 32001 (China)
3. Department of Physics, University of Illinois, Chicago, Illinois 60607 (United States)
4. Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045 (United States)

A measurement of the Lamb shift in muonic hydrogen yields a charge radius of the proton that is smaller than the CODATA value by about 5 standard deviations. We explore the possibility that new scalar, pseudoscalar, vector, and tensor flavor-conserving nonuniversal interactions may be responsible for the discrepancy. We consider exotic particles that, among leptons, couple preferentially to muons and mediate an attractive nucleon-muon interaction. We find that the many constraints from low energy data disfavor new spin-0, spin-1, and spin-2 particles as an explanation.

• OSTI ID: 21550298
• Journal Information: Physical Review Letters, Vol. 106, Issue 15; Other Information: DOI: 10.1103/PhysRevLett.106.153001; (c) 2011 American Institute of Physics; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
FLAVOR MODEL
HYDROGEN
LAMB SHIFT
MUON-NUCLEON INTERACTIONS
MUONS
PROTONS
SPIN
VECTORS
ANGULAR MOMENTUM
BARYONS
COMPOSITE MODELS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
HADRONS
INTERACTIONS
LEPTON-BARYON INTERACTIONS
LEPTON-HADRON INTERACTIONS
LEPTON-NUCLEON INTERACTIONS
LEPTONS
MATHEMATICAL MODELS
NONMETALS
NUCLEONS
PARTICLE INTERACTIONS
PARTICLE MODELS
PARTICLE PROPERTIES
QUARK MODEL
SPECTRAL SHIFT
TENSORS