  The flux of high-energy astrophysical neutrinos observed by the present
generation of neutrino detectors has already indicated a few hints of new
physics beyond the Standard Model. In this work, we show that high-energy
gamma-ray observations can also be considered as a complementary probe for
unveiling the source of high-energy astrophysical neutrino events and new
physics. Recently, the LHAASO collaboration has reported O(5000) gamma-ray
events in the energy range between 0.5 TeV -18 TeV from gamma-ray burst
GRB221009A within 2000 seconds after the initial outburst. We showed that
attenuated high-energy gamma rays can be produced from the interaction of
astrophysical neutrinos with CMB neutrinos through non-standard
self-interaction of neutrinos mediated by light scalar bosons. The non-standard
interaction of neutrinos recently took a lot of attention in cosmology for its
role in reducing Hubble tension. We have constrained the parameter space of
non-standard self-interacting neutrinos from the flux of photons observed by
LHAASO and showed consistency of the same with the resulting parameter space
from Hubble tension requirements and other recent constraints from
laboratory/cosmology.
