Post on 12-Jan-2016
Antimatter Charters School Peter Kalmus March 2005
Professor Peter I. P. KalmusQueen Mary, University of London
RETTAMITNA
ANTIMATTER
Antimatter Charters School Peter Kalmus March 2005
Objectives of Particle Physics
atomelectron
nucleus
protonneutron
quarks
Study of the ultimateconstituents of matter
Nature of the interactionsbetween them
Antimatter Charters School Peter Kalmus March 2005
Structure of the Atom
Atom
~ 10-10m
Nucleus
Early 20th Century electron, nucleus
electric forceelectromagnetism
1930s
bunch ofgrapes
Proton +
Neutron
strongforcetown
~ 10-15m
Antimatter Charters School Peter Kalmus March 2005
Antiparticles equal and oppositeproperties“predicted”, later discovered
> 200 new “elementary” (?) particles
Creation
Annihilation
+ N e- + e+ + N
e- + e+ +
1950s Antiproton, antineutron
Nobel prizes Dirac, Anderson, Blackett, Segre, Chamberlain
Einstein
E = mc2
now used in positron emission tomography
E = mc2
> 1 MeV
Antimatter Charters School Peter Kalmus March 2005
Today’s building blocks
Leptons(do not feel strong force)
electron e- -1
e-neutrino e 0
Quarks(feel strong force)
up u +2/3down d -1/3
proton = u u d+2/3 +2/3 -1/3 = +1
neutron = u d d+2/3 -1/3 -1/3 = 0
4 particles very simple
multiply by 3 (generations)multiply by 2 (antiparticles)
First generation
Antimatter Charters School Peter Kalmus March 2005
Today’s building blocks
Leptons(do not feel strong force)
electron e- -1
e-neutrino e 0
Quarks(feel strong force)
up u +2/3
down d -1/3
muon -1
-neutrino 0
tau -1
-neutrino 0
charm c +2/3
strange s -1/3
top t +2/3
bottom b -1/3
Antimatter Charters School Peter Kalmus March 2005
Today’s building blocks
Leptons(do not feel strong force)
electron e- -1
e-neutrino e 0
Quarks(feel strong force)
up u +2/3
down d -1/3
muon -1
-neutrino 0
tau -1
-neutrino 0
charm c +2/3
strange s -1/3
top t +2/3
bottom b -1/3
Also antileptonsantiquarks
6 leptons6 antileptons
6 quarks6 antiquarks
baryons q q q
antibary. q q q
mesons q q
Antimatter Charters School Peter Kalmus March 2005
Forces
Gravity
falling objectsplanet orbitsstarsgalaxies
inversesquare law
graviton
inversesquare law
photon
shortrange
W±, Z0
Electro-magnetic
atomsmoleculesopticselectronicstelecom.
Weak
betadecay
solarfusion
Strong
nuclei
particles
shortrange
gluon
Antimatter Charters School Peter Kalmus March 2005
Ultra-high energy collision
A B
Equal nos.particles &antiparticles
10 16 1 TeV
10 13 1 GeV
10 10 1 MeV
10 7 1 keV
10 4 1 eV
10 1 meV
T/K Energy
ParticleEra
NuclearEra
AtomicEra
PrimordialSoup
Sun forms
Todayps ns s ms s
1 day
1 year
Time
Era ofAstronomy
TevatronLEP
History of the UniverseLHC
Antimatter Charters School Peter Kalmus March 2005
Earth, Moon, X
Solar system X
Antistars in our Galaxy ?
Other (anti-) galaxies ?
Telescopes X
Cosmic rays ?
AMS (Space station)
Antimatter
Anti-hydrogen : made in lab
Bulk antimatter ? Where ?
Difficult to detect
Annihilation ofAntigalaxy ?
Signal ?
e+ + e - +
0.511 MeV -ray “line”
Alfven hypothesis
Radiation pressure
Antimatter Charters School Peter Kalmus March 2005
SymmetriesMany in physics Powerful tools. We consider 2
Particle antiparticle
o (1232) p + +
o (1232) p + -should occur atexactly same rate
C chargeconjugation
1
Antimatter Charters School Peter Kalmus March 2005
A B
P parity
Mirror symmetry A and B equally probable(parity conservation)
Before 1957 believed valid for all processes
Symmetries
2
Mirrorreflection
Antimatter Charters School Peter Kalmus March 2005
Communication with an Alien
radio signals
If parity conservedcannot tell which is his right hand
Antimatter Charters School Peter Kalmus March 2005
superimposeobject and mirror image
If parity conserved expect equal probabilities L and R
Parity violated in weakinteractions ! L R
60 Co 60 Ni + e- +
Parity violation
Parity conserved in all strong and e-m interactions
electrons onlyin this direction
direction of electrons in coil
radioactive cobalt source
Antimatter Charters School Peter Kalmus March 2005
Alien
Can now ask alien to set upa parity violation experimentand hence deduce right hand
This one
C violation
Also shown by same expts.
P
CC P
e-
e-
positronsin antiwire
Current reversedin antiwire
diagram looks same as original red
e+
wire
CP appearsconserved
emitted positrons go opposite way
e+
e+
e-
Antiblue
Antimatter Charters School Peter Kalmus March 2005
C violationP
CC P
e-
diagram looks same as original red
e+
CP appearsconserved
emitted positrons go opposite way
e-
Antiblue
Experiments have been done with spinning muons
Antimatter Charters School Peter Kalmus March 2005
Problem
Right-handedgreen man
Left-handedanti green man
R L?
Antimatter Charters School Peter Kalmus March 2005
Meet in space
If he holds outhis left hand
Teach him about our customs
Antimatter Charters School Peter Kalmus March 2005
Annihilation
Antimatter Charters School Peter Kalmus March 2005
CP violation
Discovered in decays of neutral kaons
- + e+ +
+ + e- +
slightly more probable (0.6 %)
K0 ( d s ) ; K0 ( d s )
KL
Now can unambiguouslydefine antimatter
If the less abundant lepton in KL decay has the same sign as the local atomic nuclei, we have antimatter
Antimatter Charters School Peter Kalmus March 2005
CP Violation
Believed to be responsible for domination of matter
Reason for CP violation not yet understood
Up till year 2000 only seen in neutral K decays
Where else might we see CP violation ?
Problem : B mesons have only very short lifetime ~ 10-12 s Travel only fraction of millimetre at low energies
Solution : Produce in asymmetric e+ e- collider, and use relativistic boost to increase lifetime.
Neutral B meson system
Antimatter Charters School Peter Kalmus March 2005
e+e-
Bo
Bo
Asymmetric : successful
aftercollision
CP violation in B system
BaBar (SLAC, USA)
Belle (KEK, Japan)
includes QMUL physicistsand graduate students
e+ e- (4S) Bo Bo
upsilon
e+e-
Bo
Bo
Symmetric: no good
aftercollision
Measured recently
Antimatter Charters School Peter Kalmus March 2005
QMULphysicist
Large CP violation observedAt BaBar and Belle
Antimatter Charters School Peter Kalmus March 2005
Unification of the fundamentalforces of nature
Electricity Magnetism Apples Planets
Electro-magnetic
Gravity
Faraday, Maxwell Newton
Antimatter Charters School Peter Kalmus March 2005
Unification of the fundamentalforces of nature
Do the W and Z particles really exist ?
Electricity Magnetism Apples Planets
Electro-magnetic
Weak Strong Gravity
Faraday, Maxwell Newton
Electroweakunified force
Salam, Weinberg, Glashow
, W +, W -, Z o 0 80 80 90 GeV
Antimatter Charters School Peter Kalmus March 2005
Antimatter Charters School Peter Kalmus March 2005
Antimatter Charters School Peter Kalmus March 2005
ColliderInject anti-protons
Injectprotons
Collide 2 beamsInside vacuum
RF cavitieselectric kick
~Bendingelectro-magnet
Focusingelectro-magnet
Carlo RubbiaAntiprotons
Simon van der MeerStochastic cooling
ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE
CERN EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
CERN 71-25Laboratory INuclear Physics Division26 November 1971
CE
RN
71-
25
LOW–MOMENTUM ANTIPROTON PRODUCTION
AT THE CERN PROTON SYNCHROTRON
P. I. P. Kalmus, E. Eisenhandler, W. R. Gibson, C. HojvatL.C.Y. Lee Chi Kwong, T.W. Pritchard, E.C. Usher and D.T.
WilliamsQueen Mary College, London
M. Harrison and W. R. RangeUniversity of Liverpool
M. A. R. Kemp, A. D. Rush and J. N. WouldsDaresbury Nuclear Physics Laboratory
G. T. J. Arnison, A. Astbury, D .P. Jones and A.S.L.ParsonsRutherford High Energy Laboratory
Antimatter Charters School Peter Kalmus March 2005
What should we look for ?
W around 1 in 108 collisionsNeedle in a haystack !
p + p W + X
e +
lots of particles
electron
W
neutrino
Antimatter Charters School Peter Kalmus March 2005
UA1 ExperimentMuon
Neutrino
Electromagcalorimeter
Hadron calorim.and magnet
Proton Antiproton
Hadron
Electron
Wire
chamber
Vacuumpipe
Muon chambers
Antimatter Charters School Peter Kalmus March 2005
Finding the W
p p collisions 109
Record on tape 975,000
Electron trigger 140,000
High ET 28,000
Hi. mom track 2,125
Points to calorim. 1,104
No other calorim. tracks 276
Angles match 167
No hadronic energy 72
Energy matches mom. 39
2 jet
23
electron+ jet11
electronno jet
5
Visualinspection
Antimatter Charters School Peter Kalmus March 2005
GeV
40
20
– 40 – 20 20 40
– 20
– 40
electrondirection E parallel
to electron
Eventswith jets
E normalto electron
Missingenergyflow
For each event, plothow much energy is missing, and thedirection relative tothe electron in which this flows
Antimatter Charters School Peter Kalmus March 2005
GeV
40
20
– 40 – 20 20 40
– 20
– 40
electrondirection E parallel
to electron
Eventswith jets
E normalto electron
Missingenergyflow
For each event, plothow much energy is missing, and thedirection relative tothe electron in which this flows
Eventswithno jets
Antimatter Charters School Peter Kalmus March 2005
W and Z particles discovered
UA1 Collaboration at CERN
Included following members of Queen Mary
Peter KalmusAlan Honma
Eric EisenhandlerRichard Keeler
Reg GibsonGiordi Salvi
Graham ThompsonThemis Bowcock
Results confirmed by another CERN collaboration,and few years later at Fermilab USA
Electroweak unification confirmed
Nature’s fundamental forcesreduced from 4 to 3
Nobel Prizes
Antimatter Charters School Peter Kalmus March 2005
p.i.p.kalmus@qmul.ac.ukhttp://www.ph.qmul.ac.uk