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High energy hadron-nucleus scattering

Description: Theoretical expectations for hadron-nucleus scattering at high energy if the basic hadron-hadron interaction is due to Regge poles and cuts arising in multiperipheral or soft field theory models are described. Experiments at Fermilab may provide a critical test of such models. (auth)
Date: January 1, 1975
Creator: Koplik, J. & Mueller, A.H.
Partner: UNT Libraries Government Documents Department

The role of the axial anomaly in determining spin-dependent parton distributions

Description: It is shown that the forward matrix elements of j{sub 5}{sup {mu}}, the flavor singlet axial vector current, do not measure the helicity carried by quarks and anti-quarks but also include a spin-dependent gluonic component due to the anomaly. Detailed phenomenological and field theoretic reasons are given for the necessity of a gluonic component in the matrix element of j{sub 5}{sup {mu}}. The first higher order corrections to the basic box and triangle graphs are discussed and shown not to modify the conclusions drawn in the leading order calculation. We close with a few comments on the possible phenomenological implications of the anomalous contribution. 25 refs., 6 figs.
Date: July 27, 1989
Creator: Carlitz, R.D.; Collins, J.C. & Mueller, A.H.
Partner: UNT Libraries Government Documents Department

Intrinsic Chevrolets at the SSC

Description: The possibility of the production at high energy of heavy quarks, supersymmetric particles and other large mass colored systems via the intrinsic twist-six components in the proton wave function is discussed. While the existing data do not rule out the possible relevance of intrinsic charm production at present energies, the extrapolation of such intrinsic contributions to very high masses and energies suggests that they will not play an important role at the SSC.
Date: January 1, 1984
Creator: Brodsky, S.J.; Collins, J.C.; Ellis, S.D.; Gunion, J.F. & Mueller, A.H.
Partner: UNT Libraries Government Documents Department

In situ real-time studies of oxygen incorporation in complex oxide thin films using spectroscopic ellipsometry and ion scattering and recoil spectrometry

Description: The surface termination of c-axis oriented YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) and the oxygen incorporation mechanism has been investigated using a unique combination of spectroscopic ellipsometry (SE) and time of flight ion scattering and recoil spectrometry (ToF-ISARS). The high surface sensitivity of the ToF-ISARS technique combined with the bulk oxygen sensitivity of SE are shown to yield complimentary information. The SE provided the film orientation and quality, while ToF-ISARS supplied surface compositional and structural information and enabled isotopic {sup 18}O tracer studies. It was determined that the O content of the film had little effect on the surface termination of the film, indicating a lack of labile Cu(1) sites at the c-axis oriented YBCO surface. Also, strong evidence for a Ba or BaO terminated structure is shown. The data related to the {sup 18}O tracer studies indicate that O from the reaction ambient incorporates only into the labile Cu(1) sites during both deposition and annealing, while stable O sites were populated with O from the sputtered target, indicating either the need for sputtered atomic O or sputtered YCuO complexes to occupy the stable Cu(2) sites.
Date: May 25, 2000
Creator: Mueller, A. H.; Gao, Y.; Irene, E. A.; Auciello, O.; Krauss, A. R. & Achultz, J. A.
Partner: UNT Libraries Government Documents Department

Studies of ferroelectric heterostructure thin films and interfaces via in situ analytical techniques.

Description: The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMs) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and interface processes, which play critical roles in film microstructure and properties. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed.
Date: August 30, 1999
Creator: Auciello, O.; Dhote, A.; Gao, Y.; Gruen, D. M.; Im, J.; Irene, E. A. et al.
Partner: UNT Libraries Government Documents Department