Saxon Fest:A Celebration

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Saxon FestA Celebration

• Beams and Bubble Chambers
• The World of Baryon Physics
• R.J.Cashmore
• Brasenose College and Dept of Physics
• Oxford

2
A Brief CV

• Born 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 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

4
Balliol 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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Research

• Thesis Oct 1969
• A Study of Elementary Particle Interactions
  using the Bubble Chamber Technique
• Pi- Proton -gt 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 ?

• 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 IJ0 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 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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Computers

• 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 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 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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The Baryon Octet

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The Baryon Decuplet
-

0

-

0

-
0
-
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The u,d and s quarks
u 2/3
d -1/3

s -1/3
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u,d,s quark structures
udd
uud

dds
uus
uds
dss
uss
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u,d,s quark structures
-

0

uuu
ddd
uud
udd
-

0
uss
uus
uds

-
0
uss
dss
-
sss
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Baryon 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 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 PSIs(1974)

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The 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 ?
Leptons
(
)
(
)
(
)
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
Quarks
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In 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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