forward collisions and spin effects in evaluating amplitudes
DESCRIPTION
Forward Collisions and Spin Effects in Evaluating Amplitudes. N. Akchurin, Texas Tech University, USA N. Buttimore , Trinity College Dublin, Ireland A. Penzo , INFN & Università di Trieste, Italy. Introduction. Proton proton collisions probe analyticity and spin dependence - PowerPoint PPT PresentationTRANSCRIPT
Forward Collisionsand Spin Effects in
Evaluating Amplitudes
N. Akchurin, Texas Tech University, USAN. Buttimore, Trinity College Dublin, Ireland A. Penzo, INFN & Università di Trieste, Italy
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Introduction
• Proton proton collisions probe analyticity and spin dependence
• A dispersion relation violation may suggest a new mass scale
• Hadronic spin effects appear in t = 0 fermion fermion scattering
• Study forward spin dependence for cross section normalisation
SPIN 2010 September 30 JülichN Buttimore
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Peripheral Proton and Ion Collisions
Hadronic spin dependence is important for • Parton distribution functions and nucleon
form factors • Measuring the proton beam polarization at
BNL RHIC, Makdisi, AIP Conf Proc 980 • Spin dependent couplings of the Pomeron,
Trueman, Phys Rev D77
September 30, 2010N. Buttimore, SPIN2010 Jülich
N. Buttimore, SPIN2010 Julich 4
Analyzing Power in CNI Region
Interference value tc = 8 p a / stot
Hadronic slope B, Bethe phase d ≈ 0.02, Real-to-imaginary ratio r ≈ 0.02, Proton mass m and anomalous
moment k = 1.7928September 30, 2010
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Global Fit to Small –t Data
September 30, 2010N. Buttimore, SPIN2010 Jülich
E704 (p=200 GeV/c) RHIC (p=100 GeV/c)☐ RHIC (√s= 200 GeV)
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Conclusions
• When all available small –t data are analyzed, the hadronic spin flip is small (value…)
• The magnitude of |r5|= 0.059 ± 0.008 and the phase angle q5= 94.1 ± 1.7 degrees
• Only statistical experimental errors are considered in this analysis. The systematic errors need to be included especially when they are comparable or larger
• pp data at 6.8 GeV suggest sizable hadronic spin flip…• Systematic errors in pC data need study as the fourth quadrant
spin-flip phase is very different from the second quadrant pp phase
• ….
September 30, 2010N. Buttimore, SPIN2010 Jülich
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Overlay Alek6.8GeV (do we need this?) maybe save it as a back up
September 30, 2010N. Buttimore, SPIN2010 Julich