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K. Abe,
T. Akagi,
P. L. Anthony,
R. Antonov,
R. G. Arnold,
T. Averett,
H. R. Band,
J. M. Bauer,
H. Borel,
P. E. Bosted, [......],
D. Walz,
F. Wesselmann,
J. L. White, K. Witte,
C. C. Young,
B. Youngman,
H. Yuta,
G. Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: Measurements are reported of the proton and deuteron spin structure functions g1p and g1d at beam energies of 29.1, 16.2, and 9.7 GeV, and g2p and g2d at a beam energy of 29.1 GeV. The integrals Γp=∫01g1p(x,Q2)dx and Γd=∫01g1d(x,Q2)dx were evaluated at fixed Q2=3(GeV/c)2 using the full data set to yield Γp=0.132±0.003(stat)±0.009(syst) and Γd=0.047±0.003±0.006. The Q2 dependence of the ratio g1/F1 was studied and found to be small for Q2>1(GeV/c)2. Within experimental precision the g2 data are well described by the twist-2 contribution, g2WW. Twist-3 matrix elements were extracted and compared to theoretical predictions. The asymmetry A2 was measured and found to be significantly smaller than the positivity limit √R for both proton and deuteron targets. A2p is found to be positive and inconsistent with zero. Measurements of g1 in the resonance region show strong variations with x and Q2, consistent with resonant amplitudes extracted from unpolarized data. These data allow us to study the Q2 dependence of the integrals Γp and Γn below the scaling region.
Phys. Rev. D. 10/1998; 58(11).
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[show abstract]
[hide abstract]
ABSTRACT: The successful operation of a GaAs‐based polarized electron source utilizing a DC high voltage gun for the SLC program at SLAC has raised the prospects for a similar source for next generation linear colliders (NGLC). A major challenge in meeting the NGLC requirements is to produce ≳1012 electrons per macrobunch from the cathode. The physics issues that are involved in limiting charge extraction from a GaAs‐type cathode and the prospects of realizing a NGLC polarized electron source based on an SLC‐type gun will be discussed. © 1995 American Institute of Physics.
AIP Conference Proceedings. 08/1995; 343(1):641-645.
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K. Abe,
T. Akagi,
P.L. Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H.R. Band,
J.M. Bauer,
H. Borel,
P.E. Bosted, [......],
D. Walz,
F. Wesselmann,
J.L. White, K. Witte,
C.C. Young,
B. Youngman,
H. Yuta,
G. Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: Measurements were made at SLAC of the cross section for scattering 29 GeV electrons from carbon at a laboratory angle of 4.5°, corresponding to 0.03<x<0.1 and 1.3<Q2<2.7 GeV2. Values of R=σL/σT were extracted in this kinematic range by comparing these data to cross sections measured at a higher beam energy by the NMC collaboration. The results are in reasonable agreement with pQCD calculations and with extrapolations of the R1990 parameterization of previous data. A new fit is made including these data and other recent results.
Physics Letters B.
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K Abe,
T Akagi,
P L Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
D. Walz,
F. Wesselmann,
J.L. White, K Witte,
C C Young,
B. Youngman,
H Yuta,
G Zapalac,
B. Zihlmann,
D Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We have measured the proton and deuteron spin structure functions g[sup p][sub 1] and g[sup d][sub 1] in the region of the nucleon resonances for W2 < 5GeV2 and Q2(similar, equals)0.5 and Q2(similar, equals)1.2GeV2 by inelastically scattering 9.7 GeV polarized electrons off polarized 15NH3 and 15ND3 targets. We observe significant structure in g[sup p][sub 1] in the resonance region. We have used the present results, together with the deep-inelastic data at higher W2, to extract Gamma (Q2)(equivalent)01 g1(x,Q2)dx. This is the first information on the low-Q2 evolution of Gamma toward the Gerasimov-Drell-Hearn limit at Q2 = 0.
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K Abe,
T Akagi,
P L Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
T Usher,
D. Walz,
J.L. White, K Witte,
C Young,
B. Youngman,
H Yuta,
G Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: The ratio g1/F1 has been measured over the range 0.03<x<0.6 and 0.3<Q2<10 (GeV/c)2 using deep-inelastic scattering of polarized electrons from polarized protons and deuterons. We find g1/F1 to be consistent with no Q2-dependence at fixed x in the deep-inelastic region Q^2>1 (GeV/c)2. A trend is observed for g1/F1 to decrease at lower Q2. Fits to world data with and without a possible Q2-dependence in g1/F1 are in agreement with the Bjorken sum rule, but Delta_q is substantially less than the quark-parton model expectation.
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K Abe,
T Akagi,
P L Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
D. Walz,
F. Wesselmann,
J.L. White, K Witte,
C Young,
B. Youngman,
H Yuta,
G Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: Measurements are reported of the proton and deuteron spin structure functions g1 at beam energies of 29.1, 16.2, and 9.7 GeV and g2 at a beam energy of 29.1 GeV. The integrals of g1 over x have been evaluated at fixed Q**2 = 3 (GeV/c)**2 using the full data set. The Q**2 dependence of the ratio g1/F1 was studied and found to be small for Q**2 > 1 (GeV/c)**2. Within experimental precision the g2 data are well-described by the Wandzura-Wilczek twist-2 contribution. Twist-3 matrix elements were extracted and compared to theoretical predictions. The asymmetry A2 was measured and found to be significantly smaller than the positivity limit for both proton and deuteron targets. A2 for the proton is found to be positive and inconsistent with zero. Measurements of g1 in the resonance region show strong variations with x and Q**2, consistent with resonant amplitudes extracted from unpolarized data. These data allow us to study the Q**2 dependence of the first moments of g1 below the scaling region.
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K Abe,
T Akagi,
P L Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
T Usher,
D. Walz,
J.L. White, K Witte,
C Young,
B. Youngman,
H Yuta,
G Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: We have measured the ratio g[sup p][sub 1]/F[sup p][sub 1] over the range 0.029 < x < 0.8 and 1.3 < Q2 < 10 (GeV/c)2 using deep-inelastic scattering of polarized electrons from polarized ammonia. An evaluation of the integral (integral)g[sup p][sub 1](x,Q2)dx at fixed Q2 = 3 (GeV/c)2 yields 0.127 ± 0.004(stat) ± 0.010(syst), in agreement with previous experiments, but well below the Ellis-Jaffe sum rule prediction of 0.160 ± 0.006. In the quark-parton model, this implies Delta q = 0.27 ± 0.10.
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K Abe,
T Akagi,
P L Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
T Usher,
D. Walz,
J.L. White, K Witte,
C Young,
B. Youngman,
H Yuta,
G Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: We report on a high-statistics measurement of the deuteron spin structure function g[sup d][sub 1] at a beam energy of 29 GeV in the kinematic range 0.029 < x < 0.8 and 1 < Q2 < 10 (GeV/c)2. The integral Gamma [sup d][sub 1] = (integral)[sup 1][sub 0]g[sup d][sub 1]dx evaluated at fixed Q2 = 3 (GeV/c)2 gives 0.042 ± 0.003(stat) ± 0.004(syst). Combining this result with our earlier measurement of g[sup p][sub 1], we find Gamma [sup p][sub 1]- Gamma [sup n][sub 1] = 0.163 ± 0.010(stat) ± 0.016(syst), which agrees with the prediction of the Bjorken sum rule with O( alpha [sup 3][sub s]) corrections, Gamma [sup p][sub 1]- Gamma [sup n][sub 1] = 0.171 ± 0.008. We find the quark contribution to the proton helicity to be Delta q = 0.30 ± 0.06.
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K Abe,
T Akagi,
P L Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
D. Walz,
F. Wesselmann,
J.L. White, K Witte,
C C Young,
B. Youngman,
H Yuta,
G Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: Measurements were made at SLAC of the cross section for scattering 29 GeV electrons from carbon at a laboratory angle of 4.5 degrees, corresponding to 0.03<x<0.1 and 1.3<Q^2<2.7 GeV^2. Values of R=sigma_L/sigma_T were extracted in this kinematic range by comparing these data to cross sections measured at a higher beam energy by the NMC collaboration. The results are in reasonable agreement with pQCD calculations and with extrapolations of the R1990 parameterization of previous data. A new fit is made including these data and other recent results.
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[show abstract]
[hide abstract]
ABSTRACT: The physico-chemical changes brought about by swift heavy ions of silicon and nickel in polyvinyl chloride (PVC) are discussed in terms of optical, electrical and chemical modifications. The electrical conductivity of the polyvinyl chloride, both in independent form as well as in blended form, increases with the increase in the ion fluence and the mass of the swift heavy ions. It was further observed that under the present experimental conditions, PVC did not have any significant influence on the electrical conductivity of PVC–PANI blend. The present work shows that swift heavy ion modification technique under limited conditions could be utilized for increasing the conductivity of insulating polymer conducting polymer (IPCP) blends.
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms.
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K. Abe,
T. Akagi,
P.L. Anthony,
R. Antonov,
R.G. Arnold,
T. Averett,
H.R. Band,
J.M. Bauer,
H. Borel,
P.E. Bosted, [......],
T. Usher,
D. Walz,
J.L. White, K. Witte,
C.C. Young,
B. Youngman,
H. Yuta,
G. Zapalac,
B. Zihlmann,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: The ratio has been measured over the range 0.03 < x < 0.6 and 0.3 < Q2 < 10 (GeV/c)2 using deep-inelastic scattering of polarized electrons from polarized protons and deuterons. We find to be consistent with no Q2-dependence at fixed x in the deep-inelastic region Q2 > 1 (GeV/c)2. A trend is observed for to decrease at lower Q2. Fits to world data with and without a possible Q2-dependence in are in agreement with the Bjorken sum rule, but Δq is substantially less than the quark-parton model expectation.
Physics Letters B.
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K Abe,
T Akagi,
P L Anthony,
R D Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
T Usher,
D. Walz,
J.L. White, K Witte,
C C Young,
B. Youngman,
H Yuta,
G H Zapalac,
B. Zihlmann,
D Zimmerman
[show abstract]
[hide abstract]
ABSTRACT: We have measured proton and deuteron virtual photon-nucleon asymmetries A2p and A2d and structure functions g2p and g2d over the range 0.03<x<0.8 and 1.3<Q2<10 (GeV/c)2 by inelastically scattering polarized electrons off polarized ammonia targets. Results for A2 are significantly smaller than the positivity limit sqrt(R) for both targets. Within experimental precision, the g2 data are well-described by the twist-2 contribution g2WW. Twist-3 matrix elements have been extracted and are compared to theorectical predictions.
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K Abe,
T Akagi,
P L Anthony,
R D Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
D. Walz,
F. Wesselmann,
J.L. White, K Witte,
C C Young,
B. Youngman,
H Yuta,
G H Zapalac,
B. Zihlmann,
D Zimmerman
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K Abe,
T Akagi,
P L Anthony,
R D Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
T Usher,
D. Walz,
J.L. White, K Witte,
C C Young,
B. Youngman,
H Yuta,
G H Zapalac,
B. Zihlmann,
D Zimmerman
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K Abe,
T Akagi,
P L Anthony,
R D Antonov,
R.G. Arnold,
T. Averett,
H R Band,
J M Bauer,
H. Borel,
P. E. Bosted, [......],
T Usher,
D. Walz,
J.L. White, K Witte,
C Young,
B. Youngman,
H Yuta,
G H Zapalac,
B. Zihlmann,
D Zimmerman
