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Full-Text Articles in Physical Sciences and Mathematics
New Search For Parity Violation In Nonresonant Neutron Scattering On Thorium, J D. Bowman, Bret E. Crawford, P P J. Delheij, C M. Frankle, M Iinuma, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, Y-F Yen, V W. Yuan
New Search For Parity Violation In Nonresonant Neutron Scattering On Thorium, J D. Bowman, Bret E. Crawford, P P J. Delheij, C M. Frankle, M Iinuma, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, Sharon L. Stephenson, Y-F Yen, V W. Yuan
Physics and Astronomy Faculty Publications
The parity-violating longitudinal asymmetry of the neutron scattering cross section has been measured for thorium in the off-resonance energy intervals from 30 to 300 eV. The observed result of (0.5±1.6)×10-6 is compared with theoretical predictions.
Electric-Octupole And Pure-Electric-Quadrupole Effects In Soft X-Ray Photoemission, Andrei Derevianko, Oliver Hemmers, S. Oblad, P. Glans, H. Wang, S. B. Whitfield, R. Wehlitz, I. A. Sellin, W. R. Johnson, Dennis W. Lindle
Electric-Octupole And Pure-Electric-Quadrupole Effects In Soft X-Ray Photoemission, Andrei Derevianko, Oliver Hemmers, S. Oblad, P. Glans, H. Wang, S. B. Whitfield, R. Wehlitz, I. A. Sellin, W. R. Johnson, Dennis W. Lindle
Environmental Studies Faculty Publications
Second-order [O(k2), k = ω/c] nondipole effects in soft-x-ray photoemission are demonstrated via an experimental and a theoretical study of angular distributions of neon valence photoelectrons in the 100–1200 eV photon-energy range. A newly derived theoretical expression for nondipolar angular distributions characterizes the second-order effects using four new parameters with primary contributions from pure-quadrupole and octupole-dipole interference terms. Independent-particle calculations of these parameters account for a significant portion of the existing discrepancy between experiment and theory for Ne 2p first-order nondipole parameters.
Parity Violation In Neutron Resonances In 115in, Sharon L. Stephenson, J D. Bowman, J Corvi, Bret E. Crawford, P P J. Delheij, C M. Frankle, M Iinuma, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, H M. Shimizu, Y-F Yen, V W. Yuan, L Zanini
Parity Violation In Neutron Resonances In 115in, Sharon L. Stephenson, J D. Bowman, J Corvi, Bret E. Crawford, P P J. Delheij, C M. Frankle, M Iinuma, J N. Knudsen, L Y. Lowie, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, E I. Sharapov, H M. Shimizu, Y-F Yen, V W. Yuan, L Zanini
Physics and Astronomy Faculty Publications
Parity nonconservation (PNC) was studied in p-wave resonances in indium by measuring the helicity dependence of the neutron total cross section in the neutron energy range 6.0–316 eV with the time-of-flight method at LANSCE. A total of 36 p-wave neutron resonances were studied in 115In, and statistically significant asymmetries were observed for nine cases. An analysis treating the PNC matrix elements as random variables yields a weak matrix element of M=(0.67-0.12+0.16) meV and a weak spreading width of Γw=(1.30-0.43+0.76)×10-7 eV.
Classical Versus Quantum Dynamics For A Driven Relativistic Oscillator, Rainer Grobe, Qichang Su, P J. Peverly, R E. Wagner
Classical Versus Quantum Dynamics For A Driven Relativistic Oscillator, Rainer Grobe, Qichang Su, P J. Peverly, R E. Wagner
Faculty publications – Physics
We compare the time evolution of the quantum-mechanical spatial probability density obtained by solving the time-dependent Dirac equation with its classical counterpart obtained from the relativistic Liouville equation for the phase-space density in a regime in which the dynamics is essentially relativistic. For a resonantly driven one-dimensional harmonic oscillator, the simplest nontrivial model system to perform this comparison, we find that, despite the nonlinearity induced by relativity, the classical ensemble description matches the quantum evolution remarkably well.
Pion-Induced Transport Of Π Mesons In Nuclei, S. G. Mashnik, R. J. Peterson, A. J. Sierk, Michael R. Braunstein
Pion-Induced Transport Of Π Mesons In Nuclei, S. G. Mashnik, R. J. Peterson, A. J. Sierk, Michael R. Braunstein
All Faculty Scholarship for the College of the Sciences
A large body of data for pion-induced neutral pion continuum spectra spanning outgoing energies near 180 MeV shows no dip there that might be ascribed to internal strong absorption processes involving the formation of Δ’s. This is the same observation previously made for the charged pion continuum spectra. Calculations in an intranuclear cascade model or a cascade exciton model with free-space parameters predict such a dip for both neutral and charged pions. We explore several medium modifications to the interactions of pions with internal nucleons that are able to reproduce the data for nuclei from 7Li through Bi.
Lifetime Effects On The Dissociation Of Core-Excited N2 And Co Molecules, N. Saito, A. Hempelmann, F. Heiserq, Oliver Hemmers, K. Wieliczek, J. Viefhaus, U. Becker
Lifetime Effects On The Dissociation Of Core-Excited N2 And Co Molecules, N. Saito, A. Hempelmann, F. Heiserq, Oliver Hemmers, K. Wieliczek, J. Viefhaus, U. Becker
Environmental Studies Faculty Publications
Vibrational-resolved ion and ion-pair yield spectra of N2 and CO taken at their 1s⃗π* resonance excitations reveal decay-channel-dependent core hole lifetimes. The linewidths of the yield spectra tend to be shortened when the number of electrons ejected in the deexcitation process increases, finally becoming narrower than the total ion yield or absorption natural lifetime width of the core-excited states of N2 and CO, respectively. In contrast to this, the linewidths of the yield spectra for the singly charged molecular ions, N2+ and CO+, are shown to be broader than their corresponding natural linewidths. …
Parity Violation In 232th Neutron Resonances Above 250 Ev, E I. Sharapov, J D. Bowman, Bret E. Crawford, P P J. Delheij, C M. Frankle, M Iinuma, J N. Knudsen, L Y. Lowie, J E. Lynch, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, Sharon L. Stephenson, Y-F Yen, V W. Yuan
Parity Violation In 232th Neutron Resonances Above 250 Ev, E I. Sharapov, J D. Bowman, Bret E. Crawford, P P J. Delheij, C M. Frankle, M Iinuma, J N. Knudsen, L Y. Lowie, J E. Lynch, A Masaike, Y Matsuda, G E. Mitchell, S I. Penttila, H Postma, N R. Roberson, S J. Seestrom, Sharon L. Stephenson, Y-F Yen, V W. Yuan
Physics and Astronomy Faculty Publications
The analysis of parity nonconservation (PNC) measurements performed on 232Th by the TRIPLE Collaboration has been extended to include the neutron energy range of 250 to 1900 eV. Below 250 eV all ten statistically significant parity violations have the same sign. However, at higher energies PNC effects of both signs were observed in the transmission of longitudinally polarized neutrons through a thick thorium target. Although the limited experimental energy resolution precluded analysis in terms of the longitudinal asymmetry, parity violations were observed and the cross section differences for positive and negative neutron helicities were obtained. For comparison, a similar …
Beyond The Dipole Approximation: Angular-Distribution Effects In The 1s Photoemission From Small Molecules, Dennis W. Lindle, Oliver Hemmers, H. Wang, P. Focke, I. A. Sellin, J. D. Mills, J. A. Sheehy, P. W. Langhoff
Beyond The Dipole Approximation: Angular-Distribution Effects In The 1s Photoemission From Small Molecules, Dennis W. Lindle, Oliver Hemmers, H. Wang, P. Focke, I. A. Sellin, J. D. Mills, J. A. Sheehy, P. W. Langhoff
Environmental Studies Faculty Publications
Over the past two decades, the dipole approximation has facilitated a basic understanding of the photoionization process in atoms and molecules. Recent experiments on the 1s inner shells of small molecules at relatively low photon energies (⩽ 1000 eV) show strong nondipole effects. They are significant and measurable at energies close to threshold, in conflict with a common assumption that the dipole approximation is valid for photon energies below 1 keV.
Production Of A Signal By Irradiated Cells Which Leads To A Response In Unirradiated Cells Characteristic Of Initiation Of Apoptosis, Fiona Lyng, C. Seymour, C. Mothersill
Production Of A Signal By Irradiated Cells Which Leads To A Response In Unirradiated Cells Characteristic Of Initiation Of Apoptosis, Fiona Lyng, C. Seymour, C. Mothersill
Articles
This study investigated the ability of medium from irradiated cells to induce early events in the apoptotic cascade, such as mobilization of intracellular calcium, loss of mitochondrial membrane potential and increase in reactive oxygen species, in cells which were never exposed to radiation. Medium from irradiated human keratinocytes was harvested and transferred to unirradiated keratinocytes. Endpoints characteristic of the initiation of apoptosis were monitored for a period of 24 h following medium transfer. Clonogenic survival was also measured. Rapid calcium fluxes (within 30 s), loss of mitochondrial membrane potential, increases in reactive oxygen species (from 6 h after medium transfer), …