1,189 research outputs found
Determination of the low Q2 evolution of the Bjorken integral
We report on an experimental determination of the Q2-dependence of the
Bjorken sum using data from Jefferson Lab Hall A and Hall B in the range 0.16 <
Q2 < 1.1 GeV2. A twist analysis is performed. Overall, the higher twist
corrections are found to be small due to a cancellation between the twist 4 and
6 terms.Comment: Contribution to the GDH04 symposium proceeding
Jefferson Lab's results on the Q^2-evolution of moments of spin structure functions
We present the recent JLab measurements on moments of spin structure
functions at intermediate and low Q^2. The Bjorken sum and Burkhardt-Cottingham
sum on the neutron are presented. The later appears to hold. Higher moments
(generalized spin polarizabilities and d_2^n) are shown and compared to chiral
perturbation theory and lattice QCD respectively.Comment: 4 pages, 2 figures, to appear in the DIS2005 Proceedings (AIP
Self-interacting scalar fields at high-temperature
We study two self-interacting scalar field theories in their high-temperature
limit using path integrals on a lattice. We first discuss the formalism and
recover known potentials to validate the method. We then discuss how these
theories can model, in the high-temperature limit, the strong interaction and
General Relativity. For the strong interaction, the model recovers the known
phenomenology of the nearly static regime of heavy quarkonia. The model also
exposes a possible origin for the emergence of the confinement scale from the
approximately conformal Lagrangian. Aside from such possible insights, the main
purpose of addressing the strong interaction here --given that more
sophisticated approaches already exist-- is mostly to further verify the
pertinence of the model in the more complex case of General Relativity for
which non-perturbative methods are not as developed. The results have important
implications on the nature of Dark Matter. In particular, non-perturbative
effects naturally provide flat rotation curves for disk galaxies, without need
for non-baryonic matter, and explain as well other observations involving Dark
Matter such as cluster dynamics or the dark mass of elliptical galaxies.Comment: 33 pages, 19 figures. Version published in Eur. Phys. J.
Measurement of the Q2-evolution of the Bjorken integral at low Q2
We report on the extraction of the Q2-dependence of the Bjorken sum between
0.16 < Q2 < 1.1 GeV2. A twist analysis performed on these data shows that the
higher twist corrections are small due to a cancellation between the twist-4
and 6 terms. The extraction of an effective strong coupling constant is
discussed.Comment: Contribution to the proceedings of the 16th International Spin
Physics Symposium, spin2004 (Trieste
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