Post on 06-Jan-2018
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Saxon Fest:A CelebrationSaxon Fest:A Celebration
Beams and Bubble ChambersThe World of Baryon Physics
R.J.CashmoreBrasenose College and Dept of Physics
Oxford
30-May-08 DHS_Glasgow 1
A Brief CVA Brief CVBorn 27 Oct 1945Education Manchester Grammar School 1956 - 63 Balliol College Oxford 1963 - 68Employment
JRF Jesus College 1968 - 70 RA Columbia University 1970 - 73
SO,PSO RAL 1973 - 90 Kelvin Prof at Glasgow Univ. 1990 - 2008Honours 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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ResearchResearchThesis 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/cNeeded 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 interaction30-May-08 DHS_Glasgow 13
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 q30-May-08 DHS_Glasgow 14
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
dds uds 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 q30-May-08 DHS_Glasgow 20
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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)30-May-08 DHS_Glasgow 22
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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
( )uuu5.0 MeV +2/3 e
10.5 MeV -1/3 e
ddd
( )ccc1.3 GeV +2/3 e
0.2 GeV -1/3 e
sss
( )ttt0.175 TeV +2/3 e
4.3 GeV -1/3 e
bbb
Lept
ons
Qua
rks
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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