The strong interaction is not well understood at low energies or for interactions with low momentum transfer. Chiral perturbation theory gives testable predictions for the nucleonic generalized ...polarizabilities, which are fundamental quantities describing the nucleon’s response to an external field. We report a measurement of the proton’s generalized spin polarizabilities extracted with a polarized electron beam and a polarized solid ammonia target in the region where chiral perturbation theory is expected to be valid. The investigated structure function g2 characterizes the internal spin structure of the proton. From its moments, we extract the longitudinal–transverse spin polarizability δLT and twist-3 matrix element and polarizability d2¯. Our results provide discriminating power between existing chiral perturbation theory calculations and will help provide a better understanding of this strong quantum chromodynamics regime.Measurements of the proton’s generalized spin polarizabilities provide discriminating power between effective descriptions of the strong interaction at low energy.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In this work, inclusive electron scattering from nuclear targets has been measured to extract the nuclear dependence of the inelastic cross section in Hall C at the Thomas Jefferson National ...Accelerator facility. Results are presented for 2H, 3He, 4He, 9B, 12C, 63Cu and 197Au at an incident electron beam energy of 5.77 GeV for a range of momentum transfer from Q2 = 2 to 7 (GeV/c)2. These data improve the precision of the existing measurements of the EMC effect in the nuclear targets at large x, and allow for more detailed examinations of the A dependence of the EMC effect.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
We present new measurements of electron scattering from high-momentum nucleons in nuclei. These data allow an improved determination of the strength of two-nucleon correlations for several nuclei, ...including light nuclei where clustering effects can, for the first time, be examined. The data also include the kinematic region where three-nucleon correlations are expected to dominate.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9 GeV. A ...large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3<x<0.8). Proportional to an average color Lorentz force, the twist-3 matrix element, dover ˜_{2}^{p}, was extracted from the measured asymmetries at Q^{2} values ranging from 2.0 to 6.0 GeV^{2}. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an unexpected scale dependence. Furthermore, when combined with the neutron data in the same Q^{2} range the results suggest a flavor independent average color Lorentz force.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
New Jefferson Lab data are presented on the nuclear dependence of the inclusive cross section from (2)H, (3)He, (4)He, (9)Be and (12)C for 0.3 < x < 0.9, Q(2) approximately 3-6 GeV(2). These data ...represent the first measurement of the EMC effect for (3)He at large x and a significant improvement for (4)He. The data do not support previous A-dependent or density-dependent fits to the EMC effect and suggest that the nuclear dependence of the quark distributions may depend on the local nuclear environment.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
We present new data on the Bjorken sum Γ‾1p−n(Q2) at 4-momentum transfer 0.021≤Q2≤0.496 GeV2. The data were obtained in two experiments performed at Jefferson Lab: EG4 on polarized protons and ...deuterons, and E97110 on polarized 3He from which neutron data were extracted. The data cover the domain where chiral effective field theory (χEFT), the leading effective theory of the Strong Force at large distances, is expected to be applicable. We find that our data and the predictions from χEFT are only in marginal agreement. This is somewhat surprising as the contribution from the Δ(1232) resonance is suppressed in this observable, which should make it more reliably predicted by χEFT than quantities in which the Δ contribution is important. The data are also compared to a number of phenomenological models with various degrees of agreement.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We report the results of a new Rosenbluth measurement of the proton electromagnetic form factors at Q2 values of 2.64, 3.20, and 4.10 GeV2. Cross sections were determined by detecting the recoiling ...proton, in contrast to previous measurements which detected the scattered electron. Cross sections were determined to 3%, with relative uncertainties below 1%. The ratio mu(p)G(E)/G(M) was determined to 4%-8% and showed mu(p)G(E)/G(M) approximately 1. These results are consistent with, and much more precise than, previous Rosenbluth extractions. They are inconsistent with recent polarization transfer measurements of similar precision, implying a systematic difference between the techniques.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Objective A biopsychosocial model was used to treat pain-associated disability in children and adolescents. We assessed the clinical outcomes of children and adolescents (8–21 years of age) with ...pain-associated disability who were treated in an interdisciplinary inpatient rehabilitation program which included physical, occupational, and recreational therapy, medicine, nursing, pediatric psychology, neuropsychology, psychiatry, social work, and education. Psychological treatment emphasized cognitive-behavioral intervention for pain and anxiety management, and behavioral shaping to increase functioning. Methods We conducted a retrospective chart review of 41consecutive patients. School attendance, sleep, and medication usage were assessed at admission and discharge; functional disability and physical mobility were assessed at admission, discharge, and 3-month follow-up. Results As a group, significant improvements were observed in school status, sleep, functional ability, physical mobility, and medication usage. Conclusion Findings support the efficacy of an inpatient interdisciplinary behavioral rehabilitation approach to the treatment of pain-associated disability in pediatric patients.
Solid 15NH3 and 15ND3 provide a highly polarizable, radiation resistant source of polarized protons and deuterons and have been used extensively in high luminosity (1035 cm-2 s-1) experiments ...investigating the spin structure of the nucleon. Over the past twenty years, the UVA polarized target group has been instrumental in producing and polarizing much of the material used in these studies, and many practical considerations have been learned in this time. In this discussion, we analyze the polarization performance of the solid ammonia targets used during the recent JLab Eg4 run. Topics include the rate of polarization decay with accumulated charge, the annealing procedure for radiation damaged targets to recover polarization, and the radiation induced change in optimum microwave frequency used to polarize the sample. We also discuss the success we have had in implementing frequency modulation of the polarizing microwave frequency.
PDF
![Low Q[sup 2] Measurement of...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/1935-0465_1551-7616_0094-243X/small "Low Q[sup 2] Measurement of g[sub 2][sup p] and the δ[sub LT] Spin Polarizability")
