Target independence of the 'proton spin' effect - INSPIRE

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Target independence of the 'proton spin' effect

G.M. Shore
(
- Swansea U.
)

Jul, 1994

5 pages

Part of QCD 94. Proceedings, Workshop, Montpellier, France, July 7-13, 1994

Published in:

Nucl.Phys.B Proc.Suppl. 39BC (1995) 101-105

Contribution to:

High-energy Physics: QCD Workshop 94

e-Print:

hep-ph/9410383 [hep-ph]

DOI:

10.1016/0920-5632(95)00051-A

Report number:

SWAT-48,
SWAT-94-48

View in:

ADS Abstract Service

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Abstract:

Recent work by the author in collaboration with S. Narison and G. Veneziano on the EMC-SMC-SLAC `proton spin' effect is reviewed. This uses a novel approach to deep inelastic scattering in which the matrix elements arising from the OPE are factorised into composite operator propagators and proper vertices. For polarised

\mu p

scattering, the composite operator propagator is equated to the square root of the first moment of the QCD topological susceptibility,

\sqrt{\chi~\prime(0)}

. We evaluate

\chi~\prime(0)

using QCD spectral sum rules and find a significant suppression relative to its OZI expectation. This is identified as the source of the violation of the Ellis-Jaffe sum rule for the first moment of the polarised proton structure function

g_1~p

. Our predictions,

\int_0~1 dx g_1~p(x;Q~2=10GeV~2) = 0.143\pm 0.005

and

\Delta\Sigma =0.353\pm 0.052

, are in excellent agreement with the new SMC data. This supports our earlier conjecture that the suppression in the flavour singlet component of the first moment of

g_1~p

is a target-independent feature of QCD related to the

U(1)

anomaly and is not a special property of the proton structure.

talk
p: spin
spin: p
p: structure function
p: polarization
polarization: p
quantum chromodynamics: sum rule
lattice field theory: susceptibility
expansion: topological
numerical calculations: interpretation of experiments

References(6)

Figures(0)

A Measurement of the Spin Asymmetry and Determination of the Structure Function g(1) in Deep Inelastic Muon-Proton Scattering

European Muon

Collaboration

•

J. Ashman
(
- Sheffield U.
)

et al.

- Phys.Lett.B 206 (1988) 364,
•
DOI:
- 10.1016/0370-2693(88)91523-7

An Investigation of the Spin Structure of the Proton in Deep Inelastic Scattering of Polarized Muons on Polarized Protons

European Muon

Collaboration

•

J. Ashman
(
- Sheffield U.
)

et al.

- Nucl.Phys.B 328 (1989) 1,
•
DOI:
- 10.1016/0550-3213(89)90089-8

Measurement of the spin dependent structure function $g_1(x)$ of the proton

Spin Muon (SMC)

Collaboration

•

D. Adams

et al.

- Phys.Lett.B 329 (1994) 399-406,
- Phys.Lett.B 339 (1994) 332-333 (erratum)
•
e-Print:
- hep-ph/9404270
•
DOI:
- 10.1016/0370-2693(94)90793-5

The U(1) Goldberger-Treiman relation and the proton 'spin': A Renormalization group analysis

G.M. Shore
(
- CERN
)
,
G. Veneziano
(
- CERN
)

- Nucl.Phys.B 381 (1992) 23-65
•
DOI:
- 10.1016/0550-3213(92)90639-S

Chiral Symmetry and the Spin of the Proton

- Phys.Lett.B 206 (1988) 309-315
•
DOI:
- 10.1016/0370-2693(88)91511-0

The Anomalous Gluon Contribution to Polarized Leptoproduction

Guido Altarelli
(
- CERN
)
,
Graham G. Ross
(
- CERN
)

- Phys.Lett.B 212 (1988) 391-396
•
DOI:
- 10.1016/0370-2693(88)91335-4