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Upper Bounds On Parity-Violating Gamma-Ray Asymmetries In Compound Nuclei From Polarized Cold Neutron Capture, M. T. Gericke, J. D. Bowman, R. D. Carlini, T. E. Chupp, K. P. Coulter, M. Dabaghyan, M. Dawkins, D. Desai, S. J. Freedman, T. R. Gentile, R. C. Gillis, G. L. Greene, F. W. Hersman, T. Ino, Gordon L. Jones, M. Kandes, B. Lauss, M. Leuschner, W. R. Lozowski, R. Mahurin, M. Mason, Y. Masuda, G. S. Mitchell, S. Muto, H. Nann, S. A. Page, S. I. Penttila, W. D. Ramsay, S. Santra, P.-N. Seo, E. I. Sharapov, T. B. Smith, W. M. Snow, W. S. Wilburn, V. Yuan, H. Zhu
Upper Bounds On Parity-Violating Gamma-Ray Asymmetries In Compound Nuclei From Polarized Cold Neutron Capture, M. T. Gericke, J. D. Bowman, R. D. Carlini, T. E. Chupp, K. P. Coulter, M. Dabaghyan, M. Dawkins, D. Desai, S. J. Freedman, T. R. Gentile, R. C. Gillis, G. L. Greene, F. W. Hersman, T. Ino, Gordon L. Jones, M. Kandes, B. Lauss, M. Leuschner, W. R. Lozowski, R. Mahurin, M. Mason, Y. Masuda, G. S. Mitchell, S. Muto, H. Nann, S. A. Page, S. I. Penttila, W. D. Ramsay, S. Santra, P.-N. Seo, E. I. Sharapov, T. B. Smith, W. M. Snow, W. S. Wilburn, V. Yuan, H. Zhu
Articles
Parity-odd asymmetries in the electromagnetic decays of compound nuclei can sometimes be amplified above values expected from simple dimensional estimates by the complexity of compound nuclear states. Using a statistical approach, we estimate the root-mean-square of the distribution of expected parity-odd correlations (s) over right arrow (n)center dot(k) over right arrow (gamma), where (s) over right arrow (n) is the neutron spin and (k) over right arrow (gamma) is the momentum of the gamma, in the integrated gamma spectrum from the capture of cold polarized neutrons on Al, Cu, and In. We present measurements of the asymmetries in these and …
Theory Of Cavity-Polariton Self-Trapping And Optical Strain In Polymer Chains, M. V. Katkov, Yuriy V. Pershin Dr, C. Piermarocchi
Theory Of Cavity-Polariton Self-Trapping And Optical Strain In Polymer Chains, M. V. Katkov, Yuriy V. Pershin Dr, C. Piermarocchi
Faculty Publications
We consider a semiconductor polymer chain coupled to a single electromagnetic mode in a cavity. The excitations of the chain have a mixed exciton-photon character and are described as polaritons. Polaritons are coupled to the lattice by the deformation potential interaction and can propagate in the chain. We find that the presence of optical excitation in the polymer induces strain on the lattice. We use a BCS variational wave function to calculate the chemical potential of the polaritons as a function of their density. We analyze first the case of a short chain with only two unit cells in order …
Casimir Forces And Non-Newtonian Gravitation, Roberto Onofrio
Casimir Forces And Non-Newtonian Gravitation, Roberto Onofrio
Dartmouth Scholarship
The search for non-relativistic deviations from Newtonian gravitation can lead to new phenomena signalling the unification of gravity with the other fundamental interactions. Various recent theoretical frameworks indicate a possible window for non-Newtonian forces with gravitational coupling strength in the micrometre range. The major expected background in the same range is attributable to the Casimir force or variants of it if dielectric materials, rather than conducting ones, are considered. Here we review the measurements of the Casimir force performed so far in the micrometre range and how they determine constraints on non-Newtonian gravitation, also discussing the dominant sources of false …
A Simple Electric Field Probe In A Gauss's Law Laboratory, Daniel O. Ludwigsen, Gregory N. Hassold
A Simple Electric Field Probe In A Gauss's Law Laboratory, Daniel O. Ludwigsen, Gregory N. Hassold
Physics Publications
Early in our calculus-based introductory course, students are introduced to electric fields and sometimes struggle with the abstraction of a vector field. They have less familiarity with the phenomena associated with electric fields, and the connection between phenomena and mathematical formalism is weaker. Our very next topic is Gauss's law.
Certifications Offered By Cost Estimating Organizations, Donald S. Remer, Karen M. Ahle, Kevin J. Alley, John Silny, Karen Hsin
Certifications Offered By Cost Estimating Organizations, Donald S. Remer, Karen M. Ahle, Kevin J. Alley, John Silny, Karen Hsin
All HMC Faculty Publications and Research
There has been an increasing trend in professional and engineering circles to place greater emphasis on official credentials. These credentials commonly come in the form of certificates – documented recognition by a professional body that an engineer or other professional has the qualifications and technical knowledge to be a practitioner in that field. These certificates are somewhat analogous to merit badges in scouting – the certification is evidence that the holder has a certain minimum level of competence in the subject area. This review will help you decide what certifications are applicable to you and the requirements to obtain a …
Evolution Of The Electron Yield Curves Of Insulators As A Function Of Impinging Electron Fluence And Energy, John R. Dennison, Alec Sim, Clint Thomson
Evolution Of The Electron Yield Curves Of Insulators As A Function Of Impinging Electron Fluence And Energy, John R. Dennison, Alec Sim, Clint Thomson
All Physics Faculty Publications
Electron emission and concomitant charge accumulation near the surface of insulators is central to understanding spacecraft charging. A study of changes in electron emission yields as a result of internal charge buildup due to electron dose is presented. Evolution of total, backscattered, and secondary yield results over a broad range of incident energies are presented for two representative insulators, Kapton and Al2O3. Reliable yield curves for uncharged insulators are measured, and quantifiable changes in yields are observed due to <100-fC/mm2 fluences. Excellent agreement with a phenomenological argument based on insulator charging predicted by the yield curve …
Positive Current Correlations Associated With Super-Poissonian Shot Noise, Yuanzhen Chen, Richard A. Webb
Positive Current Correlations Associated With Super-Poissonian Shot Noise, Yuanzhen Chen, Richard A. Webb
Faculty Publications
We report on shot noise cross spectrum measurements in a beam splitter configuration. Electrons tunneling through potential barriers are incident on a beam splitter and scattered into two separate channels. Such a partition process introduces correlations between the fluctuations of the two currents. Our work has confirmed that the generally expected negative correlations resulted from sub-Poissonian electron sources. More interestingly, positive cross correlations associated with barriers exhibiting super-Poissonian shot noise have also been observed. We have found that both positive and negative correlations can be related to the noise properties of the electron source.
Engaging Physics Students Using Environmental Lab Modules, John M. Pratte
Engaging Physics Students Using Environmental Lab Modules, John M. Pratte
Faculty and Research Publications
Discusses multi-week activity modules that use civic engagement to increase student interest and learning in physics. Components of the modules; Activities included in the modules; Assessment of student learning and interest using the modules.
Electron-Impact Ionization Of L-Shell Atomic Species, Abul Kalam Fazlul Haque, M A. Uddin, A K. Basak, Khondkar R. Karim, B C. Saha, F B. Malik
Electron-Impact Ionization Of L-Shell Atomic Species, Abul Kalam Fazlul Haque, M A. Uddin, A K. Basak, Khondkar R. Karim, B C. Saha, F B. Malik
Faculty publications – Physics
Electron impact ionization cross sections (EIICS) of 30 L-shell targets, with open- and closed-shell configurations in the isoelectronic sequences ranging from Li to Ne, are evaluated using the generalized parameters of our recent modification of BELL formula (MBELL) [Haque , Phys. Rev. A 73, 012708 (2006)]. Three sets of parameters, one each for the 1s, 2s, and 2p orbits, provide an excellent account of the experimental EIICS data of atomic targets, neutral and ionic, up to the atomic number Z=92 and incident energies up to about 250 MeV. In comparison with the quantum mechanical predictions, it is found that the …
General Classification And Analysis Of Neutron Β-Decay Experiments, Vladimir Gudkov, G. L. Greene, J. R. Calarco
General Classification And Analysis Of Neutron Β-Decay Experiments, Vladimir Gudkov, G. L. Greene, J. R. Calarco
Faculty Publications
A general analysis of the sensitivities of neutron β-decay experiments to manifestations of possible interaction beyond the standard model is carried out. In a consistent fashion, we take into account all known radiative and recoil corrections arising in the standard model. This provides a description of angular correlations in neutron decay in terms of one parameter, which is accurate to the level of ~10-5. Based on this general expression, we present an analysis of the sensitivities to new physics for selected neutron decay experiments. We emphasize that the usual parametrization of experiments in terms of the tree-level coefficients …
A Temporal Approximate Deconvolution Model For Large-Eddy Simulation, C. D. Pruett, B. C. Thomas, C. E. Grosch, T. B. Gatski
A Temporal Approximate Deconvolution Model For Large-Eddy Simulation, C. D. Pruett, B. C. Thomas, C. E. Grosch, T. B. Gatski
CCPO Publications
A temporal approximate deconvolution model (TADM) is developed for large-eddy simulation and is demonstrated for plane-channel flow at Re-tau=590. The TADM combines explicit causal time-domain filtering with linear deconvolution (defiltering) to approximate unfiltered fields and residual stress to arbitrarily high order. The TADM methodology appears to lead to a robust family of residual-stress models that should provide a viable alternative to conventional (spatial) filtering for applications in which spatial filtering is problematic, e.g., for problems requiring unstructured or highly stretched grids. (c) 2006 American Institute of Physics.
Full Shot Noise In Mesoscopic Tunnel Barriers, Yuanzhen Chen, Richard A. Webb
Full Shot Noise In Mesoscopic Tunnel Barriers, Yuanzhen Chen, Richard A. Webb
Faculty Publications
We report shot noise measurements performed in mesoscopic tunnel barriers fabricated in a GaAs∕AlGaAs heterostructure. Two sets of tunnel barriers of different size are used in the study. All large size samples and some of the small size samples show a nonlinear dependence of shot noise on tunneling current due to localized states inside the barriers. Both suppression and enhancement of shot noise have been observed. Some small size barriers, however, exhibit the shot noise behavior of an ideal tunnel barrier over a wide range of barrier transmission coefficients, tunneling currents, and bias voltages.
Lifetimes Of C-60(2-) And C-70(2-) Dianions In A Storage Ring, S. Tomita, J. U. Andersen, H. Cederquist, B. Concina, Olof E. Echt, J. S. Forster, K. Hansen, B. A. Huber, P. Hvelplund, J. Jensen, B. Liu, B. Manil, L. Maunoury
Lifetimes Of C-60(2-) And C-70(2-) Dianions In A Storage Ring, S. Tomita, J. U. Andersen, H. Cederquist, B. Concina, Olof E. Echt, J. S. Forster, K. Hansen, B. A. Huber, P. Hvelplund, J. Jensen, B. Liu, B. Manil, L. Maunoury
Physics & Astronomy
C-60(2-) and C-70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C-70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C-60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb …
Differential Cross Sections For 𝛾 + P → K⁺ + Y For Λ And Σ⁰ Hyperons, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, S. Bültmann, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, A. V. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., Clas Collaboration
Differential Cross Sections For 𝛾 + P → K⁺ + Y For Λ And Σ⁰ Hyperons, H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, S. Bültmann, G. E. Dodge, N. Guler, C. E. Hyde-Wright, H. G. Juengst, A. V. Klimenko, S. E. Kuhn, S. Tkachenko, L. B. Weinstein, J. Zhang, Et Al., Clas Collaboration
Physics Faculty Publications
High-statistics cross sections for the reactions 𝛾 + p → K⁺ + Λ and 𝛾 + p → K⁺ + Σ⁰ have been measured using CLAS at Jefferson Lab for center-of-mass energies W between 1.6 and 2.53 GeV, and for -0.85 < cos θ Kc.m. < +0.95. In the K⁺ + Λ channel we confirm a resonance-like structure near W=1.9 GeV at backward kaon angles. The position and width of this structure change with angle, indicating that more than one resonance is likely playing a role. The K⁺ + Λ channel at forward angles and all energies is well described by a t-channel scaling characteristic of Regge exchange, whereas the same scaling applied to the K⁺ + Σ⁰ channel is less successful. Several existing theoretical models are compared to the data, but none provide a good representation of the results.
Η’ Photoproduction On The Proton For Photon Energies From 1.527 To 2.227 Gev, M. Bektasoglu, S.L. Careccia, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, H. G. Juengst, A. Klein, S. E. Kuhn, A. V. Klimenko, L. M. Qin, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Yun, J. Zhang, Et Al., Clas Collaboration
Η’ Photoproduction On The Proton For Photon Energies From 1.527 To 2.227 Gev, M. Bektasoglu, S.L. Careccia, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, H. G. Juengst, A. Klein, S. E. Kuhn, A. V. Klimenko, L. M. Qin, F. Sabatié, S. Tkachenko, L. B. Weinstein, J. Yun, J. Zhang, Et Al., Clas Collaboration
Physics Faculty Publications
Differential cross sections for the reaction γp→η′p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data suggest for the first time the coupling of the η′N channel to both the S11(1535) and P11(1710) resonances, known to couple strongly to the ηN channel in photoproduction on the proton, and the importance of J=3/2 resonances in the process.
Empirical Model For The Electron-Impact K-Shell-Ionization Cross Sections, A K. F Haque, M A. Uddin, A K. Basak, K R. Karim, B C. Saha
Empirical Model For The Electron-Impact K-Shell-Ionization Cross Sections, A K. F Haque, M A. Uddin, A K. Basak, K R. Karim, B C. Saha
Faculty publications – Physics
The total cross sections of electron-impact single-K-shell ionization of 14 atomic targets ranging from H to U (1 <= Z <= 92) are calculated using a modified version of the BELI formula [Bell , J. Phys. Chem. Ref. Data 12, 891 (1983)] by incorporating both ionic and relativistic corrections in it. The proposed modified Bell model with a single set of parameters is found to provide an excellent description of the experimental data in the reduced energy range 1 <= E/I-K <= 10(6) (E and I-K are, respectively, the incident energy and ionization potential) with a performance level at least as good as any of the existing methods and models.
Electron Scattering From High-Momentum Neutrons In Deuterium, A.V. Klimenko, S. E. Kuhn, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, Gail Dodge, G. Gavalian, N. Guler, C.E. Hyde-Wright, A. Klein, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, Et Al., Clas Collaboration
Electron Scattering From High-Momentum Neutrons In Deuterium, A.V. Klimenko, S. E. Kuhn, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, Gail Dodge, G. Gavalian, N. Guler, C.E. Hyde-Wright, A. Klein, R. A. Niyazov, S. Tkachenko, L. B. Weinstein, Et Al., Clas Collaboration
Physics Faculty Publications
We report results from an experiment measuring the semiinclusive reaction 2H(e,e′ps) in which the proton ps is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CEBAF …
Erratum: Η' Photoproduction On The Proton For Photon Energies From 1.527 To 2.227 Gev (Phys. Rev. Lett. 96, Pg 062001, 2006), H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, L. M. Qin, F. Sabatié, L. B. Weinstein, Et Al., Clas Collaboration
Erratum: Η' Photoproduction On The Proton For Photon Energies From 1.527 To 2.227 Gev (Phys. Rev. Lett. 96, Pg 062001, 2006), H. Bagdasaryan, M. Bektasoglu, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, L. M. Qin, F. Sabatié, L. B. Weinstein, Et Al., Clas Collaboration
Physics Faculty Publications
No abstract provided.