Cao Z.Aharonian F.AxikeguBai Y.X.Bao Y.W.Bastieri D.Bi X.J.Bi Y.J.Bian W.Bukevich A.V.Cao Q.Cao W.Y.Cao Z.Chang J.Chang J.F.Chen A.M.Chen E.S.Chen H.X.Chen L.Chen L.Chen L.Chen M.J.Chen M.L.Chen Q.H.Chen S.Chen S.H.Chen S.Z.Chen T.L.Chen Y.Cheng N.Cheng Y.D.Cui M.Y.Cui S.W.Cui X.H.Cui Y.D.Dai B.Z.Dai H.L.Dai Z.G.DanzengluobuDong X.Q.Duan K.K.Fan J.H.Fan Y.Z.Fang J.Fang J.H.Fang K.Feng C.F.Feng H.Feng L.Feng S.H.Feng X.T.Feng Y.Feng Y.L.Gabici S.Gao B.Gao C.D.Gao Q.Gao W.Gao W.K.Ge M.M.Geng L.S.Giacinti G.Gong G.H.Gou Q.B.Gu M.H.Guo F.L.Guo X.L.Guo Y.Q.Guo Y.Y.Han Y.A.Hasan M.He H.H.He H.N.He J.Y.He Y.Hor Y.K.Hou B.W.Hou C.Hou X.Hu H.B.Hu Q.Hu S.C.Huang D.H.Huang T.Q.Huang W.J.Huang X.T.Huang X.Y.Huang Y.Ji X.L.Jia H.Y.Jia K.Jiang K.Jiang X.W.Jiang Z.J.Jin M.Kang M.M.Karpikov I.Kuleshov D.Kurinov K.Li B.B.Mahidol University2024-08-292024-08-292024-08-16Physical Review Letters Vol.133 No.7 (2024)00319007https://repository.li.mahidol.ac.th/handle/20.500.14594/100630On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are EQG,1>10 times the Planck energy EPl for the linear LIV effect, and EQG,2>6×10-8EPl for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.Physics and AstronomyArticleSCOPUS10.1103/PhysRevLett.133.0715012-s2.0-8520167500410797114