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Anomalies, symmetries and strangeness content of the proton

Pasupathy, J (2003) Anomalies, symmetries and strangeness content of the proton. In: Pramana - Journal of Physics, 61 (5). pp. 943-947.


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The matrix elements of the operators of strange quark fields $\bar{s} \Gamma s$ where \Gamma is 1 or $\gamma \mu \gamma^5 $ between a proton state is calculated. The sigma term is found to be $\approx 41 MeV$ and the SU(3) singlet axial matrix element is found to be $\approx 0.22$, both in agreement with experiment. The sigma term is found using the trace anomaly, while the determination of the axial vector current matrix element is from QCD sum rules. These correspond to $\langle p \mid 2\bar{s} s \mid p \rangle$ $ / \langle p \mid \bar{u} u + \bar{d} d $ $\mid p \rangle$ $ \approx 0.12$ and for the axial current $\Delta s \approx -0.12$, respectively. The role of the anomalies in maintaining flavor symmetry in the presence of substantial differences in quark masses is pointed out. This suggests that there is no need to invoke an intrinsic strange quark component in the proton wave function.

Item Type: Journal Article
Publication: Pramana - Journal of Physics
Publisher: Indian Academy of Sciences
Additional Information: The Copyright belongs to Indian Academy of Sciences.
Keywords: Strange quark;Proton
Department/Centre: Division of Physical & Mathematical Sciences > Centre for Theoretical Studies (Ceased to exist at the end of 2003)
Date Deposited: 07 Apr 2006
Last Modified: 19 Sep 2010 04:25
URI: http://eprints.iisc.ac.in/id/eprint/6192

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