Astroparticle Physics

Vitamin Mu - are muons more vital than we thought?

by Anatoli Fedynitch (ICRR, The University of Tokyo)

Atmospheric muons were discovered among the positrons in cosmic rays in the early 20 century. They are responsible of over 80% of cosmic radiation at ground and can reach locations buried under kilometers of rock. In the past 70 years atmospheric muons have been studied in high detail to find out more about cosmic rays and particle physics. After the 1990s progress gradually faded, and in the past decade, the atmospheric muon science is considered almost dead.
In my seminar, I would like to *revive* the attention to these versatile particles. Current high-precision calculation methods for inclusive atmospheric muon spectra treat the uncertainties of their physics "ingredients" separately and quantitatively accurate, motivating a re-analysis of available data including a rigorous handling of its systematic uncertainties. As it turns out, the high-precision of spectrometer experiments at the surface and of deep-underground laboratories of the 90s, such as LVD, Frejus, or SNO, have potential to provide new insight into very forward hadronic physics. As a potential "calibration" source, muon data can be used for high-precision atmospheric neutrino flux models for neutrino or astrophysics, and to obtain additional constraints on cosmic ray composition at the energy of the knee.
On a totally different note, atmospheric muons as the dominant source of cosmic radiation at the surface may have played an important role in the origin of life on Earth and other bodies of the solar system. Contrary to electromagnetic radiation, atmospheric muons carry polarization down to shallow underground depths. A novel idea initially developed by Noemie Globus and Roger Blandford proposes that the interaction of muon polarization with prototype molecules of the DNA has resulted in the development of homochiralization - i.e. the building blocks DNA of exclusively single handedness. To find out if there is something specific about muons on Earth, we studied the radiation deposition by polarized muons in the prime targets for the searches of extraterrestrial life in the solar system.


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Meeting ID: 921 1801 0804
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