Saxon Fest:A Celebration
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Transcript of Saxon Fest:A Celebration
Saxon Fest:A CelebrationSaxon Fest:A Celebration
Beams and Bubble Chambers
The World of Baryon Physics
R.J.Cashmore
Brasenose College and Dept of Physics
Oxford
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A Brief CVA Brief CVBorn 27 Oct 1945
Education
Manchester Grammar School 1956 - 63
Balliol College Oxford 1963 - 68
Employment
JRF Jesus College 1968 - 70
RA Columbia University 1970 - 73
SO,PSO RAL 1973 - 90
Kelvin Prof at Glasgow Univ. 1990 - 2008
Honours
FRSE 1993
FRAS 2005
OBE 2005
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Manchester Grammar SchoolManchester Grammar School
Very able and conscientious No games player,secretary of
Philosophical Society,trombonist Apart from a scholar .. Very sound
commoner Paid 30 shillings to enter and …….
Awarded a Brackenbury Open Scholarship
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Balliol CollegeBalliol College
Took Prelims in March 63 … cost 5 pounds Thereby avoiding exams for 3 years Jenkyns Prize 1965 Scott Prize 1966 Travelling Scholarship to NERC Canada
Where he was ‘most impressed by the vastness’,studied laser interferometry,and
found ‘the Canadians most friendly’
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ResearchResearch
Thesis Oct 1969
‘A Study of Elementary Particle Interactions using the Bubble Chamber Technique’
Pi- Proton -> Pi Pi Nucleon at 456/505/552 Mev/c
Thesis Adviser John Mulvey ( & Willie Chinowsky)
Acknowledges
DHW for pleasure of working in NPL
Balliol for occasional support
and Scanning Girls for their support
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Why the Topic ?Why the Topic ?
Kirz anomaly ….. pi pi mass bump that changed with incident beam energy
(In fact Norman Booth had also been implicated in this debate)
Was it an I=J=0 pipi resonance?
An S wave resonance? Was it due to a baryon resonance?
A P11 nucleon resonance?
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The BUBBLE CHAMBER and The BUBBLE CHAMBER and the BEAMSthe BEAMS
Beams 456/505/552 MeV/c
400/590/660/740 MeV/c
Needed clever design to get rid of electrons
Saclay 80cms hydrogen chamber
used at RAL (NIMROD)
and SACLAY (SATURNE)
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ComputersComputers
PDP 8 to record all the measurements
and produce mountains of paper tape KDF 9 to read the tapes and reconstruct
and kinematically fit the reactions
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Graduate Students ActivitiesGraduate Students Activities
Designed and tuned the beams Scanned and measured the film Processed all the results Developed New Analyses Wrote the paper
All chasing the energy dependence of
phase of the pipi s-wave interaction
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Baryon ResonancesBaryon Resonances
Only the ground state multiplets and a
few beyond were known
In fact piN,pipiN final states were to pave
the way for the spectrum we now know
SU(3) and SU(6) structures existed
Baryons qqq and Mesons q-anti q
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pn
+
0
0
-
-
0
The Baryon Octet
- 0 + ++
- 0 +
0-
-
The Baryon DecupletThe Baryon Decuplet
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uu 2/3 2/3dd -1/3 -1/3
ss -1/3 -1/3
The u,d and s quarksThe u,d and s quarks
pn
+
0
0
-
-
0
u,d,s quark structures
uududd
ddsuds uus
dss uss
- 0 + ++
- 0 +
0-
-
ddd udd uud uuu
uusudsuss
ussdss
sss
u,d,s quark structuresu,d,s quark structures
Baryon ResonancesBaryon Resonances
Only the ground state multiplets and a
few beyond were known
In fact piN,pipiN final states were to pave
the way for the spectrum we now know
SU(3) and SU(6) structures existed
Baryons qqq and Mesons q-anti q
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OXFORD at that TIMEOXFORD at that TIME
Dick Dalitz ,the father of ‘real’ quarks, was
the ‘great man’
The language was quarks
and no one else in the world believed in them
until DIS(1969) and PSI’s(1974)
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The Particles of the Standard ModelThe Particles of the Standard Model
( )e
~0.0 MeV 0 e
0.5 MeV -1 e
e
( )
~0.0 MeV 0 e
0.1 GeV -1 e
( )
~0.0 MeV 0 e
1.8 GeV -1 e
( )uuu
5.0 MeV +2/3 e
10.5 MeV -1/3 e
ddd
( )ccc
1.3 GeV +2/3 e
0.2 GeV -1/3 e
sss
( )ttt
0.175 TeV +2/3 e
4.3 GeV -1/3 e
bbb
Lep
ton
sQ
uar
ks
In ConclusionIn Conclusion
It has been great having you and Margaret as friends
It has been great working with you over these many years
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