Hanson Freshman Seminar

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Slide1: 

Gail G. Hanson University of California, Riverside NEUTRINO FACTORIES AND MUON COLLIDERS

OK…: 

OK… WHAT IS A MUON? WHAT IS A NEUTRINO?

Slide3: 

A MUON (m) IS LIKE AN ELECTRON, ONLY 200 TIMES HEAVIER. THE ELECTRON (e) IS THE LIGHTEST CHARGED PARTICLE. THE ELECTRON CANNOT DECAY SINCE A PARTICLE CAN DECAY ONLY TO PARTICLES LIGHTER THAN ITSELF, AND CHARGE MUST BE CONSERVED. MUONS

Slide4: 

SINCE THE MUON IS HEAVIER THAN THE ELECTRON, IT CAN DECAY INTO IT: THE EXTRA PARTICLES ARE NEUTRINOS.

Slide5: 

NEUTRINOS WERE FIRST SEEN (OR NOT SEEN) IN NUCLEAR DECAYS (BETA DECAY) IN WHICH AN EXTRA INVISIBLE MASSLESS PARTICLE WAS NEEDED TO DESCRIBE THE OBSERVATIONS: NEUTRINOS

NEUTRINOS: 

NEUTRINOS NEUTRINOS (n), THEN ARE INVISIBLE MASSLESS PARTICLES. LATER IT WAS FOUND THAT NEUTRINOS CAME IN THREE FLAVORS: ( ) ( ) ( ) ne e- nm m- nt t-

NEUTRINOS: 

NEUTRINOS (THE TAU (t) IS A THIRD MEMBER OF THIS FAMILY, LIKE A MUON, BUT EVEN HEAVIER.) THE FLAVOR, WHICH IS CALLED LEPTON NUMBER, IS CONSERVED.

NEUTRINOS: 

NEUTRINOS NOW JUST WHEN PHYSICISTS THOUGHT THEY HAD ALL OF THIS UNDERSTOOD, TWO PUZZLING OBSERVATIONS WERE MADE….

DEFICIT OF SOLAR NEUTRINOS: 

DEFICIT OF SOLAR NEUTRINOS ELECTRON NEUTRINOS (ne) ARE PRODUCED BY THE NUCLEAR FUSION REACTIONS RESPONSIBLE FOR THE ENERGY OF THE SUN. THEORETICAL PREDICTIONS WERE MADE FOR THE NUMBER THAT SHOULD BE OBSERVED ON EARTH - THE “SOLAR MODEL.”

DEFICIT OF SOLAR NEUTRINOS: 

DEFICIT OF SOLAR NEUTRINOS OBSERVATIONS OF THESE ELECTRON NEUTRINOS DID NOT AGREE WITH THE PREDICTIONS - ONLY ABOUT ONE-HALF THE PREDICTED NUMBER WERE OBSERVED (FIRST BY RAY DAVIS - 2002 NOBEL PRIZE - AT THE HOMESTAKE MINE IN SOUTH DAKOTA).

DEFICIT OF ATMOSPHERIC NEUTRINOS: 

DEFICIT OF ATMOSPHERIC NEUTRINOS AN EXPERIMENT IN JAPAN, KAMIOKANDE, CONFIRMED DAVIS’S RESULT (MASATOSHI KOSHIBA - 2002 NOBEL PRIZE). KAMIOKANDE, FOLLOWED BY SUPERKAMIOKANDE, ALSO OBSERVED A DEFICIT OF MUON NEUTRINOS (nm), PRODUCED BY COSMIC RAYS IN THE EARTH’S ATMOSPHERE.

NEUTRINO OSCILLATIONS: 

NEUTRINO OSCILLATIONS BOTH OF THESE OBSERVATIONS CAN BE EXPLAINED IF THE ELECTRON NEUTRINOS FROM THE SUN AND THE MUON NEUTRINOS PRODUCED BY COSMIC RAYS CHANGE TO ANOTHER FLAVOR OF NEUTRINO BEFORE REACHING THE EARTH.

NEUTRINO OSCILLATIONS: 

NEUTRINO OSCILLATIONS SOLAR NEUTRINOS: ne nm or nt ATMOSPHERIC NEUTRINOS: nm nt NEUTRINOS OSCILLATE FROM ONE FLAVOR TO ANOTHER

NEUTRINO OSCILLATIONS: 

NEUTRINO OSCILLATIONS HOWEVER, FOR OSCILLATION TO OCCUR Dm2 = m (n2) 2 - m (n1) 2 CANNOT BE 0 FOR THE PAIRS OF NEUTRINOS INVOLVED. THIS MEANS THAT SOME NEUTRINOS MUST HAVE MASS!

MUON COLLIDERS: 

MUON COLLIDERS MEANWHILE, OTHER PHYSICISTS WERE DEVELOPING STORAGE RING ACCELERATORS IN WHICH POSITIVE AND NEGATIVE MUONS WOULD COLLIDE. COLLIDING m+ AND m- BEAMS OFFERED THE POSSIBILITY OF SMALLER, CHEAPER HIGH ENERGY COLLIDERS, BECAUSE MUONS RADIATE LESS THAN ELECTRONS.

COMPARISON OF HIGH ENERGY COLLIDERS: 

COMPARISON OF HIGH ENERGY COLLIDERS

HIGGS FACTORY: 

HIGGS FACTORY m+ m-

NEUTRINO FACTORY: 

NEUTRINO FACTORY FIRST STEP TOWARDS A MUON COLLIDER: ONE MUON BEAM IN A STORAGE RING. AN INTENSE NEUTRINO BEAM FROM THE MUON DECAYS . A NEUTRINO FACTORY!

NEUTRINO FACTORY: 

NEUTRINO FACTORY m-

NEUTRINO FACTORY: 

NEUTRINO FACTORY NO OTHER COMPARABLE SOURCE OF ELECTRON NEUTRINO OR ELECTRON ANTINEUTRINO BEAMS (ne OR ne). CONVENTIONAL NEUTRINO BEAMS ARE MUON NEUTRINOS (FROM p+ m+ nm).

HOW TO MAKE A MUON BEAM: 

HOW TO MAKE A MUON BEAM A MUON BEAM IS MADE FROM DECAYS OF PIONS ( p- m- nm ), WHICH HAVE BEEN PRODUCED FROM PROTONS STRIKING A TARGET. ONE MAJOR PROBLEM IS HOW TO MAKE THE MUON BEAM NARROW - QUICKLY, BEFORE THE MUONS DECAY. THIS IS CALLED COOLING THE BEAM.

INTERNATIONAL MUON IONIZATION COOLING EXPERIMENT (MICE): 

INTERNATIONAL MUON IONIZATION COOLING EXPERIMENT (MICE) Experimental demonstration of ionization cooling

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p m n MICE