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Title: A test of local Lorentz invariance with Compton scattering asymmetry

Here, we report on a measurement of the constancy and anisotropy of the speed of light relative to the electrons in photon-electron scattering. We also used the Compton scattering asymmetry measured by the new Compton polarimeter in Hall~C at Jefferson Lab to test for deviations from unity of the vacuum refractive index ($n$). For photon energies in the range of 9 - 46 MeV, we obtain a new limit of $$1-n < 1.4 \times 10^{-8}$$. In addition, the absence of sidereal variation over the six month period of the measurement constrains any anisotropies in the speed of light. These constitute the first study of Lorentz invariance using Compton asymmetry. Within the minimal standard model extension framework, our result yield limits on the photon and electron coefficients $$\tilde{\kappa}_{0^+}^{YZ}, c_{TX}, \tilde{\kappa}_{0^+}^{ZX}$$, and $$c_{TY}$$. Though, these limits are several orders of magnitude larger than the current best limits, they demonstrate the feasibility of using Compton asymmetry for tests of Lorentz invariance. For future parity violating electron scattering experiments at Jefferson Lab we will use higher energy electrons enabling better constraints.
 [1] ;  [2] ; ORCiD logo [2]
  1. Mississippi State Univ., Mississippi State, MS (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. Mississippi State Univ., Mississippi State, MS (United States)
Publication Date:
Report Number(s):
JLAB-PHY-16-2362; DOE/OR/23177-4042; arXiv:1611.09173
Journal ID: ISSN 0217-7323; TRN: US1701151
Grant/Contract Number:
AC05-06OR23177; FG02-07ER41528
Accepted Manuscript
Journal Name:
Modern Physics Letters A
Additional Journal Information:
Journal Volume: 31; Journal Issue: 38; Journal ID: ISSN 0217-7323
World Scientific Publishing
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Compton scattering; Lorentz invariance; vacuum refractive index
OSTI Identifier: