Most stringent constraints yet on the violation of a fundamental symmetry
Under the leadership TOMA Kenji , Theoretical Astrophysics Group, Department of Earth and Space Science, Graduate School of Science, Osaka University (he is also Fellow [SPD], Japan Society for the Promotion of Science), MUKOHYAMA Shinji , Specially Appointed Associate Professor, Kavli Institute for the Physics and Mathematics of the Universe (KAVLI IPMU), International Institute for Advanced Studies, The University of Tokyo, YONEOTKU Daisuke , Graduate School of Natural Science and Technology, Associate Professor, Kanazawa University, a group of researchers detected polarization of distant gamma-ray bursts at the most precise levels so far using an astronomical observation device independently made in Japan, demonstrating that the polarization had not rotated during its long journey. This result leads to the most stringent constraint on Charge-Parity-Time (CPT) violation. It is expected a revised quantum gravity theory will develop based on this group's research achievements.
Abstract
We report the strictest observational verification of CPT invariance in the photon sector, as a result of gamma-ray polarization measurement of distant gamma-ray bursts (GRBs), which are brightest stellar-size explosions in the universe. We detected the gamma-ray polarization of three GRBs with high significance, and the source distances may be constrained by a well-known luminosity indicator for GRBs. For the Lorentz- and CPT-violating dispersion relation E_{+-}^2=p^2 +- 2 \xi p^3/M_{Pl}, where +- denotes different circular polarization states of the photon, the parameter \xi is constrained as |\xi|<O(10^{-15}). Barring precise cancellation between quantum gravity effects and dark energy effects, the stringent limit on the CPT-violating effect leads to the expectation that quantum gravity presumably respects the CPT invariance.
Figure 1
Figure 2 （Courtesy of JAXA）
To learn more about this research, please read the full research report entitled " Strict Limit on CPT Violation from Polarization of Gamma-Ray Bursts " at this page of the Physical Review Letters website.
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