ELFT HÍRADÓ

[Szommer Peter <szpl AT metal.elte.hu>]

ELTE Fizikai Intézet

                              ORTVAY KOLLOKVIUM
                                
                    2012. május 24., csütörtök, 15 órakor
                Az ELTE Pázmány Péter s. 1/A alatti épületében
                           földszinti 0.81 előadóban


   Alan A. Watson (School of Physics and Astronomy, University of Leeds):

   "Cosmic Rays: Then, Now and the Future - from the ionisation of air
                            to beyond the LHC"

		    /Jánossy-Marx memorial lecture/ 


Kivonatos ismertetés: 
The study of cosmic rays has been generous to many disciplines, including 
particle physics, carbon dating and radio astronomy: it has thus had 
scientific and societal impact. They were discovered in 1912 as a result 
of the efforts by some of the most distinguished scientists of that era 
who were puzzled by their inability to explain the discharge of ionisation 
chambers. I will describe some of the early work that led, inter alia, to 
the discovery of the positron, the muon and the first strange particles 
and thus to the birth of particle physics. In 1938 it was found that showers 
of particles that arrive at the earth simultaneously are produced by primary 
cosmic rays of ~1015 eV, about 105 times more energetic than any particles 
that had been contemplated before. I will discuss how study of these showers 
has led to the discovery of cosmic rays of energies as great as 3?1020 eV, 
challenging our understanding of where and how they can be created. Data 
from the Pierre Auger Observatory, the largest cosmic-ray detector ever 
built, is now being used for astrophysical studies and to give glimpses of 
some hadronic physics at centre-of-mass energies more than 4 times greater 
than are accessible at the LHC.