Scientists explain how a 300 TeV photon could reach Earth
Physicists are investigating how a 300 TeV photon from a gamma-ray burst reached Earth, as standard physics suggests it should have been absorbed by cosmic background radiation. Researchers propose that axion-like particles or violations of Lorentz invariance might explain the anomaly.
Why it matters
This discovery could provide the first empirical evidence for 'new physics' beyond the Standard Model, potentially reshaping our understanding of fundamental particle interactions.
On 9 October 2022, a gamma-ray burst called GRB 221009A sent an enormous amount of high-energy radiation toward Earth. The Large High Altitude Air Shower Observatory ( LHAASO ) detected thousands of photons from the event, including some above 10 TeV. More than an hour later, the Carpet cosmic ray detector recorded something much harder to explain: a photon-like event with an estimated energy of 300 (+43/-38) TeV. At that energy, according to standard physics, the photon should have disappeared during its journey to Earth.
Giorgio Galanti of INAF and Marco Roncadelli of INFN have now examined what could allow such a photon to survive. Their explanation, reported in Physical Review Letters , involves two hypothetical effects: axion-like particles, or ALPs, and a possible violation of Lorentz invariance.
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