2015-04-27 Alan Astbury R. Keeler Scien st 1934 -- 2014
1 Scienti ic Antecedents
• Graduate of Nantwich and Acton Grammar School • Alan told me he was par cularly lucky to have excellent teachers • First Class Honours degree in physics at the University 2015-04-27 of Liverpool • PhD research supervisors (University of Liverpool): R. Keeler • Sir Alec Merrison, • Hugh Muirhead (was a member of Powell’s group that discovered the pion and an ac ve member of UA1). He wrote a well known textbook.
2 Outline
Overview of Alan’s scien fic work in historical order.
• His worked covered nuclear physics to high energy par cle physics
2015-04-27 Two themes emerge:
• Alan worked on the leading scien fic problems of his me. R. Keeler • He used the most technologically advanced apparatus that was available
3 Liverpool Synchrocyclotron
Photo of the rota ng capacitor used to modulate the RF at the 400 MeV proton accelerator. An external beam could be
extracted.
2015-04-27 R. Keeler
4 Liverpool (graduate Student)
Capture Rates for Nega ve Muons in Various Elements
Proc. Phys. Soc. 72, (1958)
• Physics interest was tes ng the theory of universal weak 2015-04-27 interac ons • External nega ve par cle beam (86 % pions, 11% electrons, 3% R. Keeler muons) • Muons stopped in target and decay me measured
5 Liverpool ( Leverhulm Research Fellow) Angular Distribu on of Neutrons Following Nuclear Capture of Polarized Muons Phys. Rev. Le ers 15, 1959 Tes ng V-A weak coupling
Results support parity viola on
µ− + p → n+ν 2015-04-27 ! ! ! Harwell neutron counter with N(θ)∝1+ασ i p/ p gamma ray suppression R. Keeler 15% polariza on for stopped muons in sulfur target !⊗!magnetic!field
Asymmetry in direc on of n emission
6 Liverpool ( Leverhulm Research Fellow)
A measurement of the Total Cross Sec on for the Produc on of Neutral Pions in Proton-Proton Collisions at
383 MeV Proc. Phys. Soc. 78 (1961)
Uses a measurement of gamma rays at a special angle 2015-04-27
γ dσ (θ ) R. Keeler σ = 2π ppπ 0 dΩ where cos−1( 1/3) {37° ,102 ) !θ = ± = °
Result: 59±9 μb
Mandelstam Resonance Theory 7 cannot account for all of the produc on cross sec on Berkeley
Search for Neutrino-induced Reac ons
Physical Review Le ers 11 (1963) p + n ν µ + → µ +
! 2015-04-27 • W mass > 1.1 GeV
OR R. Keeler • cross sec on less than 4x10-32 (~10-40)
8 Berkeley
Using the 184 inch synchrotron
Commissioned a bent-crystal spectrometer
Measured 2015-04-27 Pionic X-rays R. Keeler
Results presented at conferences.
9 Rutherford Appleton Laboratory RAL (Research Associate)
Nimrod Weak Focusing proton synchrotron 2015-04-27 7 GeV, 1012 protons / pulse R. Keeler 0.5 Hz pulse rate.
Start opera ons 1963
10
CJSD/JD retirement/July 02/pg4 RAL Nimrod
Two Pion Decay of the Meson K 0 2015-04-27 ! 2 Phys. Rev. Le . 14 (1965) Throughout its life, physics programme was directed mainly to studying baryon resonances • Nimrod beamlines in 1964 R. Keeler • First generation experiments measured π ±±pKp,and pptotal cross-sections, differential Confirma on of CP viola on in K-long decays cross-sections and polarisation • Also Kd± total cross-section, ππ− pn→→0 and η nnppn and charge exchange processes momentum spectrum 1.5 < p< 5.0 GeV/c K 0 CJSD/JD retirement/July 02/pg5 ! 2 5 m evacuated decay chamber Decay par cles are momentum analyzed by two 11 spectrometers with bending magnets and sonic spark chambers
RAL CP Violation
• 54±9 2pi events observed • BR = (2.08±0.35)x10-3 Today’s value=(1.967±10)x10-3
2015-04-27 K2pi R. Keeler K3pi Ke3 Kmu3
pions in the forward 12 direction RAL (Tenured PSO)
Measurement of the Electron Asymmetry Parameter in the Decay of Polarized Hyperons. Σ− Nucl. Phys. B39 (1972)
Cabbibo Theory • 1.13 GeV/c pions − • Measured polariza on is small Σ 2015-04-27 P=-0.32±11 R. Keeler − p+ − K + π + → Σ + Σ− → n+ e− +ν 43 decays observed g Result: A = −0.4+0.52 g −1.5 ! V g 13 A = +0.3 Predic on: g ! V RAL Nucleon-Nucleon
Small Angle Proton-Proton Sca ering at 7.85 GeV/c Phys. Le s. 14 (1965)
Measure the cross sec on in the very forward direc on. 2015-04-27 Strong-EM interference region will give phase
Total cross sec on can be calculated from the op cal theorem R. Keeler
14 RAL
Another group reported anomalous result that violated the
Op cal Theorem
2015-04-27 Results here are consistent with other data and predicted dispersion rela on R. Keeler
15 CERN PS Antiproton Physics CERN Yellow reports: 71-25, 72-10, 74-10 Papers
_ + − + Differen al Cross Sec on for between 0.8 and 2.4 GeV/c !pp → π π ,K K
Phys. Le B 47 (1973) 2015-04-27
_ Interpreta ons of the Differen al Cross Sec ons for . !pp → π π R. Keeler Phys. Le . B 47 (1973)
− + Some Observa ons on the Differen al Cross sec ons for . !pp → K K Phys. Le . B 49 (1974)
16 CERN PS
Electrosta cally separated an proton beam Wire chamber based magne c spectrometer
2015-04-27 R. Keeler
17 CERN PS
Angular
distribu ons measured
at 10 incident 2015-04-27 momenta.
R. Keeler Phase shi analysis done.
18 CERN PS
Phase shi analysis
There are many more states available in 2015-04-27 an proton proton
annihila on than there R. Keeler are in proton-proton interac ons.
This table keeps track of various fit results 19 RAL
Kaon-nucleon interac ons searching for a forbidden S=1, I=0
baryon state
Polariza on in K+n Charge Exchange Sca ering Between 0.851 2015-04-27 GeV/c and 1.351 GeV/c
Phys. Le . B R. Keeler
No forbidden states detected.
20 UA1 (co-spokesperson)
An proton-proton
collider 540 GeV Centre of Mass 2015-04-27 R. Keeler
21 UA1 Hadron Calorimeter
UK provides:
• Hadron Calorimeter (Iron-Scin llator with wavelength shi er readout)
• Return yoke for a transverse magne c field 2015-04-27 • Inside the box were a: • Lead-Scin llator R. Keeler electromagne c calorimeter • Central Dri Chamber
22 UA1 Hadron Calorimeter 0.8 Resolu on = E(GeV ) !
2015-04-27 R. Keeler
Missing Transverse Energy Resolu on of each component is Gaussian σ = 0.4⋅ E i !!E!measured!in!GeV with ! ∑ i T where the sum is typically < 100 GeV 23
UA1 Trigger
50 kHz event rate Reduced to 3Hz • Tape wri ng speed
Calorimeter trigger was combined with a muon trigger 2015-04-27
Eventually a 168E (emulator) was used as a high level trigger R. Keeler
24 UA1 startup Group Enormous ! T n ! i s ! t h e ! p r o ! b < a b n i li t y > ! o = f ! o b 6 s e . 5 r v 7 i n g ! n ! c h a r g e d ! t r a c k s 25 R. Keeler 2015-04-27 UA1 W Missing Transverse Energy (Martyn Corden – U. Birmingham)
2015-04-27 R. Keeler
26 UA1 W
Experimental Observa on of Isolated Large Transverse Energy Electrons with associated Missing Energy at √s=540 GeV.
Phys. Le s 122B (1983) 2015-04-27 R. Keeler
M = 81+5 !GeV/c2 ! W −5
27 Telegram to CERN DG from 2015-04-27 Margaret R. Keeler Thatcher, PM UK 28 Margaret Thatcher
2015-04-27 R. Keeler
29
British PM 2015-04-27 telegram R. Keeler to Alan
30 W discovery
2015-04-27 R. Keeler
31 UA1 Z
Experimental Observa on of Lepton Pairs of Invariant Mass around 95 GeV/c2 at the CERN SPS Collider
Phys. Le s B126 (1983) 2015-04-27
2 M = 95.2±2.5!GeV/c R. Keeler ! Z
32 UA1 W & Z Electron angular distribu on W is spin 1 par cle ρ and Sin2(θ ) measured
W 2015-04-27 R. Keeler
33 UA1 Di-Jets Spin 1 Gluon exchange Factoriza on à leading order structure func ons
2015-04-27 R. Keeler
Bill Sco RAL
34 UA1 3-Jets
Scale breaking
Running of the strong coupling constant 2015-04-27 R. Keeler
35 UA1 3 Jets
2015-04-27
Gluon R. Keeler Bremsstrahlung
36 Alan arrives in Victoria (1983)
Earliest group photo I could find
2015-04-27 R. Keeler
37 UA1 Ramping Run
SPS cycled between 200 and 900 GeV.
2015-04-27 R. Keeler
38 UA1 Bose-Einstein Correlations
First Student in Canada - Margret Fincke-Keeler Bose-Einstein Correla ons in An -p p Interac ons at √s=0.2 TeV to 0.9 TeV Nucl. Phys. B 226 (1989)
2015-04-27 R. Keeler
39 TMP 2,2,4,4 tetramethylpentane
• Does it compensate?
2015-04-27 R. Keeler
40 No, it does not. SLD
Designed and built liquid argon- lead electromagne c calorimeter in collabora on with Caltech. 2015-04-27 R. Keeler
41 OPAL (Director of TRIUMF)
LEP: Electron-positron collider Z pole and then above the WW threshold
Victoria Group worked on:
• Silicon microvertex detector upgrade 2015-04-27 • Responsible for near-real me data reconstruc on
Our tau physics work started with three technical notes that Alan took R. Keeler a very big interest in: TN 139 (1993) A New Clustering Algorithm for tau Decays A. Astbury et al TN 186 (1993) A New Clustering Algorithm for tau Decays : II R. Sobie TN174 (1993) A Study of Electromagne c Shower Profiles in the Electromagne c Barrel Calorimeter 42 M. Vincter, A. Astbury, R. Keeler, R. Sobie OPAL
Some thesis topics that Alan was involved with:
1. The W Boson Spin Density matrix at OPAL (I. Bailey – Lancaster)
2. Search for Excited Charged Leptons in Electron-Positron 2015-04-27 Collisions (B. Vachon – McGill) 3. A Precision Measurement of the Ra o of the Effec ve R. Keeler Vector to Axial-Vector Couplings of the Weak Neutral Current at the Z0 Pole (M. Vincter – Carleton) 4. Measurement of the Neutral Current in the Standard Model using the Tau Polariza on Asymmetries Determined from − − the decay (M. τ → ρ ντ Rosvick – industry) 5. Measurement of the Product Branching Ra o f (b → Λ )BR(Λ → Λl−ν X) (Johannes ! b b Steuerer – Industry) 43
ATLAS
Hadronic Endcap
Calorimeter 2015-04-27 R. Keeler
44 Module 0 - prototype
First module made at TRIUMF and tested in the North Hall at
CERN 2015-04-27 R. Keeler
45 A Sample Talk
A typical aside -
2015-04-27 A reference to King Canute R. Keeler
Not sure what inexorable event was being referred to
46 ATLAS
UVic summer 2013
- contribu ng good council and sharp physics insight 2015-04-27 R. Keeler
47 48 R. Keeler 2015-04-27