ANTIMATTER
RETTAMITNA
Professor Peter I. P. Kalmus
Queen Mary, University of London
Antimatter
Charters School
Peter Kalmus
March 2005
Objectives of Particle Physics
atom
electron
Study of
the ultimate
constituents
of matter
nucleus
proton
neutron
Nature of the
interactions
between them
Antimatter
Charters School
quarks
Peter Kalmus
March 2005
Structure of the Atom
Early 20th Century
1930s
electron, nucleus
electric force
electromagnetism
Nucleus
Atom
bunch of
grapes
-
~ 10 10m
-
~ 10 15m
Proton +
town
Antimatter
Charters School
Neutron
Peter Kalmus
March 2005
strong
force
Antiparticles
equal and opposite
properties
“predicted”, later discovered
Creation
g + N
e- + e+ + N
Einstein
> 1 MeV
Annihilation
e- + e+
g + g
E = mc2
now used in positron emission tomography
1950s
Antiproton, antineutron
Nobel prizes
Dirac, Anderson, Blackett, Segre, Chamberlain
> 200 new “elementary” (?) particles
Antimatter
Charters School
Peter Kalmus
E = mc2
March 2005
Today’s building blocks
Leptons
Quarks
(do not feel strong force)
(feel strong force)
electron
e-neutrino
4 particles
ene
-1 up
0 down
very simple
u
d
proton = u u d
+2/3 +2/3 -1/3 = +1
+2/3
-1/3
neutron = u d d
+2/3 -1/3 -1/3 = 0
First generation
multiply by 3 (generations)
multiply by 2 (antiparticles)
Antimatter
Charters School
Peter Kalmus
March 2005
Today’s building blocks
Leptons
Quarks
(do not feel strong force)
(feel strong force)
electron
e-neutrino
ene
muon
m- -1
charm
m-neutrino
nm
tau
t-neutrino
Antimatter
-1 up
0 down
u
+2/3
d
-1/3
c
+2/3
0
strange s
-1/3
t-
-1
top
t
+2/3
nt
0
bottom b
-1/3
Charters School
Peter Kalmus
March 2005
Today’s building blocks
Leptons
Quarks
(do not feel strong force)
(feel strong force)
Also
antileptons
antiquarks
electron
e-neutrino
ene
muon
m- -1
charm
c
+2/3
m-neutrino
nm
0
strange s
-1/3
tau
t-
-1
top
t
+2/3
antibary. q q q
t-neutrino
nt
0
bottom b
-1/3
mesons
Antimatter
-1 up
0 down
Charters School
u
+2/3
d
-1/3
Peter Kalmus
6 leptons
6 antileptons
6 quarks
6 antiquarks
baryons q q q
March 2005
qq
Forces
Electromagnetic
Weak
atoms
molecules
optics
electronics
telecom.
beta
decay
solar
fusion
particles
inverse
square law
short
range
short
range
inverse
square law
±
gluon
graviton
photon
Antimatter
W , Z0
Charters School
Strong
nuclei
Peter Kalmus
March 2005
Gravity
falling
objects
planet
orbits
stars
galaxies
Ultra-high energy collision
A
B
Equal nos.
particles &
antiparticles
Antimatter
Charters School
Peter Kalmus
March 2005
History of the Universe
LHC
Antimatter
Anti-hydrogen : made in lab
Bulk antimatter ? Where ?
Earth, Moon, X
Solar system X
Difficult to detect
Antistars in our Galaxy ?
Other (anti-) galaxies ?
Annihilation of
Antigalaxy ?
Signal ?
e+ + e g+g
0.511 MeV g-ray “line”
Telescopes X
Cosmic rays ?
AMS (Space station)
g
g
g
Alfven hypothesis
Radiation pressure
Antimatter
Charters School
Peter Kalmus
March 2005
Symmetries
Many in physics
Powerful tools.
We consider 2
1
Particle
antiparticle
Do (1232)
p + p-
Do (1232)
p + p+
Antimatter
Charters School
Peter Kalmus
C
charge
conjugation
should occur at
exactly same rate
March 2005
Symmetries
P
parity
2
Mirror
reflection
A
Mirror symmetry
B
A and B equally probable
(parity conservation)
Before 1957
Antimatter
Charters School
believed valid for all processes
Peter Kalmus
March 2005
Communication with an Alien
radio signals
If parity conserved
cannot tell which is
his right hand
Antimatter
Charters School
Peter Kalmus
March 2005
Parity violation
If parity conserved
expect equal
probabilities L and R
superimpose
object and
mirror image
Parity conserved in all
strong and e-m interactions
electrons only
in this direction
Parity violated in weak
interactions ! L
R
60 Co
60
Ni + e- + n
direction of
electrons in coil
Antimatter
Charters School
Peter Kalmus
radioactive
cobalt source
March 2005
Alien
This one
Can now ask alien to set up
a parity violation experiment
and hence deduce right hand
Antimatter
Charters School
Peter Kalmus
March 2005
C violation
Also shown by
same expts.
Current
reversed
in antiwire
Antiblue
diagram looks
same as
original red
CP appears
conserved
P
ee-
e-
wire
C
CP
e+
e+
e+
positrons
in antiwire
emitted
positrons go
opposite way
C violation
P
Experiments have
been done with
spinning muons
m-
e-
m-
eC
CP
Antiblue
diagram looks
same as
original red
m+
CP appears
conserved
Antimatter
Charters School
e+
emitted positrons
go opposite way
Peter Kalmus
March 2005
Problem
?
R
L
Right-handed
green man
Antimatter
Charters School
Peter Kalmus
Left-handed
anti green man
March 2005
Teach him about our customs
Meet in space
If he holds out
his left hand
Antimatter
Charters School
Peter Kalmus
March 2005
Annihilation
Antimatter
Charters School
Peter Kalmus
March 2005
CP violation
Discovered in decays of neutral kaons
K0 ( d s ) ;
K0 ( d s )
p- + e+ + n
slightly more probable (0.6 %)
p+ + e- + n
Now can unambiguously
define antimatter
KL
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
Up till year 2000
only seen in neutral K decays
Believed to be responsible for domination of matter
Reason for CP violation not yet understood
Where else might we see CP violation ?
Neutral B meson system
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.
Antimatter
Charters School
Peter Kalmus
March 2005
CP violation
in B system
Measured recently
includes QMUL physicists
and graduate students
BaBar (SLAC, USA)
e+ e-  (4S)  Bo Bo
Belle (KEK, Japan)
Symmetric: no good
e+
e-
upsilon
Asymmetric : successful
e-
e+
Bo
after
collision
Bo
after
collision
Bo
Antimatter
Charters School
Peter Kalmus
March 2005
Bo
Large CP violation observed
At BaBar and Belle
QMUL
physicist
Antimatter
Charters School
Peter Kalmus
March 2005
Unification
of the fundamental
forces of nature
Faraday, Maxwell
Electricity
Newton
Magnetism
Apples
Electromagnetic
Antimatter
Charters School
Planets
Gravity
Peter Kalmus
March 2005
Unification
of the fundamental
forces of nature
Faraday, Maxwell
Newton
Electricity
Magnetism
Electromagnetic
Weak
Apples
Planets
Gravity
Strong
Salam, Weinberg, Glashow
Electroweak
unified force
g, W +, W -, Z o
0 80 80 90 GeV
Do the W and Z particles really exist ?
Antimatter
Charters School
Peter Kalmus
March 2005
Antimatter
Charters School
Peter Kalmus
March 2005
Antimatter
Charters School
Peter Kalmus
March 2005
Collider
~
RF cavities
electric kick
Bending
electromagnet
Carlo Rubbia
Antiprotons
Focusing
electromagnet
Collide 2
beams
Inside
vacuum
Simon van der Meer
Stochastic cooling
Inject
protons
Antimatter
Charters School
Peter Kalmus
March 2005
Inject antiprotons
CERN 71-25
CERN 71-25
Laboratory I
Nuclear Physics Division
26 November 1971
ORGANISATION EUROPÉENNE POUR LA RECHERCHE NUCLÉAIRE
CERN
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
LOW–MOMENTUM ANTIPROTON
PRODUCTION
AT THE CERN PROTON SYNCHROTRON
P. I. P. Kalmus, E. Eisenhandler, W. R. Gibson, C. Hojvat
L.C.Y. Lee Chi Kwong, T.W. Pritchard, E.C. Usher and D.T. Williams
Queen Mary College, London
M. Harrison and W. R. Range
University of Liverpool
M. A. R. Kemp, A. D. Rush and J. N. Woulds
Daresbury Nuclear Physics Laboratory
G. T. J. Arnison, A. Astbury, D .P. Jones and A.S.L.Parsons
Rutherford High Energy Laboratory
What should we look for ?
W
around 1 in 108 collisions
electron
Needle in a haystack !
W
p + p
W + X
neutrino
e+n
lots of particles
Antimatter
Charters School
Peter Kalmus
March 2005
Antimatter
Charters School
Peter Kalmus
March 2005
Finding the W
p p collisions
109
Angles match
Record on tape
Electron trigger
High ET
167
975,000
No hadronic energy
72
Energy matches mom.
39
140,000
28,000
Hi. mom track
2,125
Points to calorim.
1,104
Visual
inspection
2 jet
23
No other calorim. tracks 276
Antimatter Charters School
Peter Kalmus
electron
+ jet
11
March 2005
electron
no jet
5
Missing
energy
flow
electron
direction
Events
with jets
– 40
For each event, plot
how much energy is
missing, and the
direction relative to
the electron in which
this flows
Antimatter
Charters School
GeV
40
E n parallel
to electron
20
– 20
20
40
En normal
to electron
– 20
– 40
Peter Kalmus
March 2005
Missing
energy
flow
electron
direction
Events
with jets
– 40
For each event, plot
how much energy is
missing, and the
direction relative to
the electron in which
this flows
Antimatter
Charters School
GeV
40
E n parallel
to electron
20
– 20
20
40
En normal
to electron
– 20
Events
with
no jets
– 40
Peter Kalmus
March 2005
W and Z particles discovered
UA1 Collaboration at CERN
Included following members of Queen Mary
Peter Kalmus
Alan Honma
Eric Eisenhandler
Richard Keeler
Reg Gibson
Giordi Salvi
Graham Thompson
Themis Bowcock
Results confirmed by another CERN collaboration,
and few years later at Fermilab USA
Electroweak unification confirmed
Nature’s fundamental forces
reduced from 4 to 3
Nobel Prizes
Antimatter
Charters School
Peter Kalmus
March 2005
[email protected]
http://www.ph.qmul.ac.uk
Antimatter
Charters School
Peter Kalmus
March 2005