Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.
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http://dx.doi.org/10.1126/science.adg9328 | DOI Listing |
Science
June 2023
Key Laboratory of Particle Astrophysics & Experimental Physics Division & Computing Center, Institute of High Energy Physics, Chinese Academy of Sciences, 100049 Beijing, China.
Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory (LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.
View Article and Find Full Text PDFScience
April 2022
Istituto Nazionale di Fisica Nucleare Bologna, I-40127 Bologna, Italy.
Phys Rev Lett
July 2021
Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, CH-3012 Bern, Switzerland.
Recently, both ATLAS and CMS measured the decay h→μ^{+}μ^{-}, finding a signal strength with respect to the standard model expectation of 1.2±0.6 and 1.
View Article and Find Full Text PDFPhys Rev Lett
October 2018
Leinweber Center for Theoretical Physics (LCTP), University of Michigan, Ann Arbor, Michigan 48109, USA.
Future neutron-antineutron (n-n[over ¯]) oscillation experiments, such as at the European Spallation Source and the Deep Underground Neutrino Experiment, aim to find first evidence of baryon number violation. We investigate implications of an improved n-n[over ¯] oscillation search for baryogenesis via interactions of n-n[over ¯] mediators, parametrized by an effective field theory (EFT). We find that even in a minimal EFT setup there is overlap between the parameter space probed by n-n[over ¯] oscillation and the region that can realize the observed baryon asymmetry of the Universe.
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