Measurement of inclusive spin structure functions of the deuteron (original) (raw)

Moments of the spin structure functions g1p and g1d for 0.05<Q<3.0 GeV

Physics Letters B, 2009

The spin structure functions g for the proton and the deuteron have been measured over a wide kinematic range in x and Q using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05<Q<5 GeV and W<3 GeV. The first moments of g for the proton and deuteron are presented - both have a negative slope at low Q, as predicted by the extended Gerasimov-Drell-Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ0p is also reported. This quantity shows strong Q dependence at low Q. Our analysis of the Q evolution of the first moment of g shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ0p data and Chiral Perturbation calculations for γ0p, even at the lowest Q.

Moments of the spin structure functions g1p and g1d for 0.05

Physics Letters B, 2009

The spin structure functions g1 for the proton and the deuteron have been measured over a wide kinematic range in x and Q 2 using 1.6 and 5.7 GeV longitudinally polarized electrons incident upon polarized NH3 and ND3 targets at Jefferson Lab. Scattered electrons were detected in the CEBAF Large Acceptance Spectrometer, for 0.05 < Q 2 < 5 GeV 2 and W < 3 GeV. The first moments of g1 for the proton and deuteron are presented-both have a negative slope at low Q 2 , as predicted by the extended Gerasimov-Drell-Hearn sum rule. The first extraction of the generalized forward spin polarizability of the proton γ p 0 is also reported. This quantity shows strong Q 2 dependence at low Q 2. Our analysis of the Q 2 evolution of the first moment of g1 shows agreement in leading order with Heavy Baryon Chiral Perturbation Theory. However, a significant discrepancy is observed between the γ p 0 data and Chiral Perturbation calculations for γ p 0 , even at the lowest Q 2 .

Precise determination of the deuteron spin structure at low to moderate<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML">mml:msupmml:miQmml:mn2with CLAS and extraction of the neutron contribution

Physical review, 2015

We present the final results for the deuteron spin structure functions obtained from the full data set collected with Jefferson Lab's CLAS in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2 and 5.8 GeV were scattered from deuteron (15 ND3) targets, dynamically polarized along the beam direction, and detected with CLAS. From the measured double spin asymmetry, the virtual photon absorption asymmetry A d 1 and the polarized structure function g d 1 were extracted over a wide kinematic range (0.05 GeV 2 < Q 2 < 5 GeV 2 and 0.9 GeV < W < 3 GeV). We use an unfolding procedure and a parametrization of the corresponding proton results to extract from these data the polarized structure functions A n 1 and g n 1 of the (bound) neutron, which are so far unknown in the resonance region, W < 2 GeV. We compare our final results, including several moments of the deuteron and neutron spin structure functions, with various theoretical models and expectations as well as parametrizations of the world data. The unprecedented precision and dense kinematic coverage of these data can aid in future extractions of polarized parton distributions, tests of perturbative QCD predictions for the quark polarization at large x, a better understanding of quark-hadron duality, and more precise values for higher-twist matrix elements in the framework of the Operator Product Expansion.