Phys. Rev. D
49,
5641–5670
(1994)
Measurement of kinematic and nuclear dependence of R=σL/σT in deep inelastic electron scattering
S. Dasu et al.
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S. Dasu*, P. de Barbaro, A. Bodek, H. Harada†, M. W. Krasny‡, K. Lang§, and E. M. Riordan**
University of Rochester, Rochester, New York 14627
L. Andivahis, R. Arnold, D. Benton††, P. Bosted, G. deChambrier, A. Lung‡‡, S. E. Rock, and Z. M. Szalata
The American University, Washington, D.C. 20016
R. C. Walkera, B. W. Filippone, J. Jourdanb, R. Milnerc, R. McKeown, and D. Potterveldd
California Institute of Technology, Pasadena, California 91125
A. Para
Fermi National Accelerator Laboratory, Batavia, Illinois 60510
F. Dietrich and K. Van Bibber
Lawrence Livermore National Laboratory, Livermore, California 94550
J. Button-Shafer, B. Debebe, and R. S. Hicks
University of Massachusetts, Amherst, Massachusetts 01003
R. Gearhart and L. W. Whitlowe
Stanford Linear Accelerator Center, Stanford, California 94305
J. Alster
University of Tel-Aviv, Ramat Aviv, Tel-Aviv 69978, Israel
Received 4 November 1993; published in the issue dated 1 June 1994
We report results on a precision measurement of the ratio R=σL/σT in deep inelastic electron-nucleon scattering in the kinematic range 0.2≤x≤0.5 and 1≤Q2≤10 (GeV/c)2. Our results show, for the first time, a clear falloff of R with increasing Q2. Our R results are in agreement with QCD predictions only when corrections for target mass effects and some additional higher twist effects are included. At small x, the data on R favor structure functions with a large gluon contribution. We also report results on the differences RA-RD and the cross section ratio σA/σD between Fe and Au nuclei and the deuteron. Our results for RA-RD are consistent with zero for all x, Q2 indicating that possible contributions to R from nuclear higher twist effects and spin-0 constituents in nuclei are not different from those in nucleons. The ratios σA/σD from all recent experiments, at all x, Q2 values, are now in agreement.
© 1994 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevD.49.5641
DOI:
10.1103/PhysRevD.49.5641
PACS:
13.60.Hb, 12.38.Qk, 25.30.Fj
*Present address: Department of Physics, University of Wisconsin, Madison, WI 53706. †Present address: Mitsubishi Electric Co., Kokusai Bldg, Rm 730, 3-1-1 Marunouchi, Chiyoda-ku, Tokyo 100, Japan. ‡Present address: IN 2P3 - CNRS, Universites Paris VI et VII, Paris, France. §Present address: Department of Physics, University of Texas, Austin, TX 78712. **Present address: Stanford Linear Accelerator Center, Stanford, CA 94309. ††Present address: Department of Physics, University of Pennsylvania, Philadelphia, PA 19104. ‡‡Present address: California Institute of Technology, Pasadena, CA 91125. aPresent address: Department of Physics, University of Rochester, Rochester, NY 14627. bPresent address: Department of Physics, CH-4056, Basel, Switzerland. cPresent address: Department of Physics, MIT, Cambridge, MA 02138. dPresent address: Argonne National Laboratory, Argonne, IL 60439-4843. ePresent address: MEC Laboratory, Daikin Industries, Tsukuba, Japan 305.
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