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Articles 661 - 690 of 1959
Full-Text Articles in Physical Sciences and Mathematics
Complete Momentum Balance In Ionization Of H₂ By 75-Kev-Proton Impact For Varying Projectile Coherence, Sachin D. Sharma, T. P. Arthanayaka, Ahmad Hasan, B. R. Lamichhane, J. Remolina, Adolph P. Smith, Michael Schulz
Complete Momentum Balance In Ionization Of H₂ By 75-Kev-Proton Impact For Varying Projectile Coherence, Sachin D. Sharma, T. P. Arthanayaka, Ahmad Hasan, B. R. Lamichhane, J. Remolina, Adolph P. Smith, Michael Schulz
Physics Faculty Research & Creative Works
We report on a kinematically complete experiment on ionization of H2 by proton impact. While a significant impact of the projectile coherence properties on the scattering-angle dependence of double-differential cross sections (DDCSs), reported earlier, is confirmed by the present data, only weak coherence effects are found in the electron and recoil-ion momentum dependence of the DDCSs. This suggests that the phase angle in the interference term is determined primarily by the projectile momentum transfer rather than by the recoil-ion momentum. We therefore cannot rule out the possibility that the interference observed in our data is not primarily due to …
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations In The Data Releases 10 And 11 Galaxy Samples, Lauren Anderson, Eric Aubourg, Shun Saito, For Full List Of Authors, See Publisher's Website.
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations In The Data Releases 10 And 11 Galaxy Samples, Lauren Anderson, Eric Aubourg, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present a one per cent measurement of the cosmic distance scale from the detections of the baryon acoustic oscillations (BAO) in the clustering of galaxies from the Baryon Oscillation Spectroscopic Survey, which is part of the Sloan Digital Sky Survey III. Our results come from the Data Release 11 (DR11) sample, containing nearly one million galaxies and covering approximately 8500 square degrees and the redshift range 0.2 < z < 0.7. We also compare these results with those from the publicly released DR9 and DR10 samples. Assuming a concordance Λ cold dark matter (ΛCDM) cosmological model, the DR11 sample covers a volume of 13 Gpc3 and is the largest region of the Universe ever surveyed at this density. We measure the correlation function and power spectrum, including density-field reconstruction of the BAO feature. The acoustic features …
Search For Gravitational Wave Ringdowns From Perturbed Intermediate Mass Black Holes In Ligo-Virgo Data From 2005-2010, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Search For Gravitational Wave Ringdowns From Perturbed Intermediate Mass Black Holes In Ligo-Virgo Data From 2005-2010, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We report results from a search for gravitational waves produced by perturbed intermediate mass black holes (IMBH) in data collected by LIGO and Virgo between 2005 and 2010. The search was sensitive to astrophysical sources that produced damped sinusoid gravitational wave signals, also known as ringdowns, with frequency 50 ≤ f0/Hz ≤ 2000 and decay timescale 0.0001 ≲ τ/s ≲ 0.1 characteristic of those produced in mergers of IMBH pairs. No significant gravitational wave candidate was detected. We report upper limits on the astrophysical coalescence rates of IMBHs with total binary mass 50 ≤ M/M⊙ ≤ 450 and …
Waveforms For Optimal Sub-Kev High-Order Harmonics With Synthesized Two- Or Three-Colour Laser Fields, Cheng Jin, Guoli Wang, Hui Wei, Anh-Thu Le, C. D. Lin
Waveforms For Optimal Sub-Kev High-Order Harmonics With Synthesized Two- Or Three-Colour Laser Fields, Cheng Jin, Guoli Wang, Hui Wei, Anh-Thu Le, C. D. Lin
Physics Faculty Research & Creative Works
High-order harmonics extending to the X-ray region generated in a gas medium by intense lasers offer the potential for providing tabletop broadband light sources but so far are limited by their low conversion efficiency. Here we show that harmonics can be enhanced by one to two orders of magnitude without an increase in the total laser power if the laser's waveform is optimized by synthesizing two- or three-colour fields. The harmonics thus generated are also favourably phase-matched so that radiation is efficiently built up in the gas medium. Our results, combined with the emerging intense high-repetition MHz lasers, promise to …
Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs …
Gravitational Waves From Known Pulsars: Results From The Initial Detector Era, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Gravitational Waves From Known Pulsars: Results From The Initial Detector Era, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and …
Simultaneous Constraints On The Growth Of Structure And Cosmic Expansion From The Multipole Power Spectra Of The Sdss Dr7 Lrg Sample, Akira Oka, Shun Saito, Takahiro Nishimichi, Atsushi Taruya, Kazuhiro Yamamoto
Simultaneous Constraints On The Growth Of Structure And Cosmic Expansion From The Multipole Power Spectra Of The Sdss Dr7 Lrg Sample, Akira Oka, Shun Saito, Takahiro Nishimichi, Atsushi Taruya, Kazuhiro Yamamoto
Physics Faculty Research & Creative Works
The anisotropic galaxy clustering on large scales provides us with a unique opportunity to probe into the gravity theory through the redshift-space distortions (RSDs) and theAlcock-Paczynski effect. Using the multipole power spectra up to hexadecapole (ℓ = 4), of the luminous red galaxy (LRG) sample in the Data Release 7 (DR7) of the Sloan Digital Sky Survey II (SDSS-II), we obtain simultaneous constraints on the linear growth rate f, angular diameter distance DA, and Hubble parameter H at redshift z = 0.3. For this purpose, we first extensively examine the validity of a theoretical model for the non-linear …
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Including Covariance Matrix Errors, Will J. Percival, Ashley J. Ross, Shun Saito, For Full List Of Authors, See Publisher's Website.
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Including Covariance Matrix Errors, Will J. Percival, Ashley J. Ross, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We present improved methodology for including covariance matrices in the error budget of Baryon Oscillation Spectroscopic Survey (BOSS) galaxy clustering measurements, revisiting Data Release 9 (DR9) analyses, and describing a method that is used in DR10/11 analyses presented in companion papers. The precise analysis method adopted is becoming increasingly important, due to the precision that BOSS can now reach: even using as many as 600 mock catalogues to estimate covariance of two-point clustering measurements can still lead to an increase in the errors of ~20 per cent, depending on how the cosmological parameters of interest are measured. In this paper, …
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Testing Gravity With Redshift Space Distortions Using The Power Spectrum Multipoles, Florian Beutler, Shun Saito, For Full List Of Authors, See Publisher's Website.
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Testing Gravity With Redshift Space Distortions Using The Power Spectrum Multipoles, Florian Beutler, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We analyse the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 (DR11) sample, which consists of 690 827 galaxies in the redshift range 0.43 < z < 0.7 and has a sky coverage of 8498 deg2. We perform our analysis in Fourier space using a power spectrum estimator suggested by Yamamoto et al. We measure the multipole power spectra in a self-consistent manner for the first time in the sense that we provide a proper way to treat the survey window function and the integral constraint, without the commonly used assumption of an isotropic power spectrum and without the need to split the survey into …
Young Double Slit Interference Effects At Quantum Level, Zehra Nur Ozer, Hari Chaluvadi, Melike Ulu, Mevlüt Doğan, Bekir Aktaş, Don H. Madison
Young Double Slit Interference Effects At Quantum Level, Zehra Nur Ozer, Hari Chaluvadi, Melike Ulu, Mevlüt Doğan, Bekir Aktaş, Don H. Madison
Physics Faculty Research & Creative Works
The currently accepted model for quantum interference resulting from the emission of electron waves from two scattering centers induced by either light or charged particle impact is analogous to Young's emission of two light waves from two slits. In this work we show that this simple classical wave model is incomplete and that there is a more complicated quantum interference pattern for low energy ionization caused by electron impact.
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Signs Of Neutrino Mass In Current Cosmological Data Sets, Florian Beutler, Shun Saito, For Full List Of Authors, See Publisher's Website.
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Signs Of Neutrino Mass In Current Cosmological Data Sets, Florian Beutler, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We investigate the cosmological implications of the latest growth of structure measurement from the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 with particular focus on the sum of the neutrino masses, Σmv. We examine the robustness of the cosmological constraints from the baryon acoustic oscillation (BAO) scale, the Alcock-Paczynski effect and redshift-space distortions (DV/rs, FAP, fσ8) of Beutler et al., when introducing a neutrino mass in the power spectrum template. We then discuss how the neutrino mass relaxes discrepancies between the cosmic microwave background (CMB) and other low-redshift …
Phonon Density Of States And Anharmonicity Of Uo₂, Judy W. Pang, Aleksandr V. Chernatynskiy, Bennett C. Larson, William J. Buyers, Douglas L. Abernathy, Kenneth J. Mcclellan, Simon R. Phillpot
Phonon Density Of States And Anharmonicity Of Uo₂, Judy W. Pang, Aleksandr V. Chernatynskiy, Bennett C. Larson, William J. Buyers, Douglas L. Abernathy, Kenneth J. Mcclellan, Simon R. Phillpot
Physics Faculty Research & Creative Works
Phonon density of states (PDOS) measurements have been performed on polycrystalline UO2 at 295 and 1200 K using time-of-flight inelastic neutron scattering to investigate the impact of anharmonicity on the vibrational spectra and to benchmark ab initio PDOS simulations performed on this strongly correlated Mott insulator. Time-of-flight PDOS measurements include anharmonic linewidth broadening, inherently, and the factor of ~7 enhancement of the oxygen spectrum relative to the uranium component by the increased neutron sensitivity to the oxygen-dominated optical phonon modes. The first-principles simulations of quasiharmonic PDOS spectra were neutron weighted and anharmonicity was introduced in an approximate way by …
First Searches For Optical Counterparts To Gravitational-Wave Candidate Events, M. Constancio Jr., Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
First Searches For Optical Counterparts To Gravitational-Wave Candidate Events, M. Constancio Jr., Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers …
Criticality And Quenched Disorder: Harris Criterion Versus Rare Regions, Thomas Vojta, José A. Hoyos
Criticality And Quenched Disorder: Harris Criterion Versus Rare Regions, Thomas Vojta, José A. Hoyos
Physics Faculty Research & Creative Works
We employ scaling arguments and optimal fluctuation theory to establish a general relation between quantum Griffiths singularities and the Harris criterion for quantum phase transitions in disordered systems. If a clean critical point violates the Harris criterion, it is destabilized by weak disorder. At the same time, the Griffiths dynamical exponent z' diverges upon approaching the transition, suggesting unconventional critical behavior. In contrast, if the Harris criterion is fulfilled, power-law Griffiths singularities can coexist with clean critical behavior, but z' saturates at a finite value. We present applications of our theory to a variety of systems including quantum spin chains, …
Role Of Electron Saddle Swaps In The Photon Spectra Following Li³⁺ Charge-Exchange Collisions With H*(N = 2), Na(3s), Na*(3p), And Li(2s) Targets, Sebastian Otranto, R. Hoekstra, Ronald E. Olson
Role Of Electron Saddle Swaps In The Photon Spectra Following Li³⁺ Charge-Exchange Collisions With H*(N = 2), Na(3s), Na*(3p), And Li(2s) Targets, Sebastian Otranto, R. Hoekstra, Ronald E. Olson
Physics Faculty Research & Creative Works
The role of electron saddle swaps in collisions of bare Li with metastable hydrogen and alkali-metal atoms is investigated by means of the classical trajectory Monte Carlo method. In particular, we show that oscillations as a function of collision energy in the photon spectra resulting from charge exchange are directly related to the number of potential-saddle crossings that a receding electron can achieve during a given reaction. The range of impact energies spanned is 0.01-50 keV/amu, an area of interest for diagnostic purposes in tokamak nuclear fusion power reactors.
Kapitza Resistance Of Si/Sio₂ Interface, Bowen Deng, Aleksandr V. Chernatynskiy, Marat Khafizov, David H. Hurley, Simon R. Phillpot
Kapitza Resistance Of Si/Sio₂ Interface, Bowen Deng, Aleksandr V. Chernatynskiy, Marat Khafizov, David H. Hurley, Simon R. Phillpot
Physics Faculty Research & Creative Works
A phonon wave packet dynamics method is used to characterize the Kapitza resistance of a Si/SiO2 interface in a Si/SiO2/Si heterostructure. By varying the thickness of SiO2 layer sandwiched between two Si layers, we determine the Kapitza resistance for the Si/SiO 2 interface from both wave packet dynamics and a direct, non-equilibrium molecular dynamics approach. The good agreement between the two methods indicates that they have each captured the anharmonic phonon scatterings at the interface. Moreover, detailed analysis provides insights as to how individual phonon mode scatters at the interface and their contribution to the Kapitza …
Two-Center Interferences In Dielectronic Transitions In H₂⁺+ He Collisions, Shaofeng Zhang, Daniel Fischer, Michael Schulz, Alexander B. Voitkiv, Arne Senftleben, Alexander Dorn, Joachim Hermann Ullrich, Xinwen Ma, Robert Moshammer
Two-Center Interferences In Dielectronic Transitions In H₂⁺+ He Collisions, Shaofeng Zhang, Daniel Fischer, Michael Schulz, Alexander B. Voitkiv, Arne Senftleben, Alexander Dorn, Joachim Hermann Ullrich, Xinwen Ma, Robert Moshammer
Physics Faculty Research & Creative Works
Molecular two-center interferences in a collision induced excitation of H2+ projectile ions, with simultaneous ionization of helium target atoms, are investigated in a kinematically complete experiment. In the process under investigation, the helium atom is singly ionized and simultaneously the molecular hydrogen ion is dissociated. Different collision mechanisms are identified and interference fringes emerging from a correlated first-order mechanism and from an independent second-order process are observed.
Position-Dependent Diffusion Of Light In Disordered Waveguides, Alexey Yamilov, Raktim Sarma, Brandon Redding, Ben Payne, Heeso Noh, Hui Cao
Position-Dependent Diffusion Of Light In Disordered Waveguides, Alexey Yamilov, Raktim Sarma, Brandon Redding, Ben Payne, Heeso Noh, Hui Cao
Physics Faculty Research & Creative Works
We present direct experimental evidence for position-dependent diffusion in open random media. The interference of light in time-reversed paths results in renormalization of the diffusion coefficient, which varies spatially. To probe the wave transport inside the system, we fabricate two-dimensional disordered waveguides and monitor the light intensity from the third dimension. Change the geometry of the system or dissipation limits the size of the loop trajectories, allowing us to control the renormalization of the diffusion coefficient. This work shows the possibility of manipulating wave diffusion via the interplay of localization and dissipation.
Contact Process On Generalized Fibonacci Chains: Infinite-Modulation Criticality And Double-Log Periodic Oscillations, Hatem Barghathi, David Nozadze, Thomas Vojta
Contact Process On Generalized Fibonacci Chains: Infinite-Modulation Criticality And Double-Log Periodic Oscillations, Hatem Barghathi, David Nozadze, Thomas Vojta
Physics Faculty Research & Creative Works
We study the nonequilibrium phase transition of the contact process with aperiodic transition rates using a real-space renormalization group as well as Monte Carlo simulations. The transition rates are modulated according to the generalized Fibonacci sequences defined by the inflation rules A → ABk and B → A. For k=1 and 2, the aperiodic fluctuations are irrelevant, and the nonequilibrium transition is in the clean directed percolation universality class. For k ≥ 3, the aperiodic fluctuations are relevant. We develop a complete theory of the resulting unconventional "infinite-modulation" critical point, which is characterized by activated dynamical scaling. Moreover, observables …
Dynamical (E,2e) Studies Of Tetrahydropyran And 1,4-Dioxane, J. D. Builth-Williams, G. Da Silva, L. Chiari, D. B. Jones, Hari Chaluvadi, Don H. Madison, M. J. Brunger
Dynamical (E,2e) Studies Of Tetrahydropyran And 1,4-Dioxane, J. D. Builth-Williams, G. Da Silva, L. Chiari, D. B. Jones, Hari Chaluvadi, Don H. Madison, M. J. Brunger
Physics Faculty Research & Creative Works
We present experimental and theoretical results for the electron-impact ionization of the highest occupied molecular orbitals of tetrahydropyran and 1,4-dioxane. Using an (e,2e) technique in asymmetric coplanar kinematics, angular distributions of the slow ejected electron, with an energy of 20 eV, are measured when incident electrons at 250 eV ionize the target and scatter through an angle of either -10° or -15°. The data are compared with calculations performed at the molecular 3-body distorted wave level. Fair agreement between the theoretical model and the experimental measurements was observed. The similar structures for these targets provide key insights for assessing the …
Phonon Thermal Transport Through Tilt Grain Boundaries In Strontium Titanate, Zexi Zheng, Xiang Chen, Bowen Deng, Aleksandr V. Chernatynskiy, Shengfeng Yang, Jinjun Xiong, Youping Chen
Phonon Thermal Transport Through Tilt Grain Boundaries In Strontium Titanate, Zexi Zheng, Xiang Chen, Bowen Deng, Aleksandr V. Chernatynskiy, Shengfeng Yang, Jinjun Xiong, Youping Chen
Physics Faculty Research & Creative Works
In this work, we perform nonequilibrium molecular dynamics simulations to study phonon scattering at two tilt grain boundaries (GBs) in SrTiO3. Mode-wise energy transmission coefficients are obtained based on phonon wave-packet dynamics simulations. The Kapitza conductance is then quantified using a lattice dynamics approach. The obtained results of the Kapitza conductance of both GBs compare well with those obtained by the direct method, except for the temperature dependence. Contrary to common belief, the results of this work show that the optical modes in SrTiO3 contribute significantly to phonon thermal transport, accounting for over 50% of the Kapitza …
Strong-Randomness Infinite-Coupling Phase In A Random Quantum Spin Chain, Fawaz Hrahsheh, José A. Hoyos, Rajesh Narayanan, Thomas Vojta
Strong-Randomness Infinite-Coupling Phase In A Random Quantum Spin Chain, Fawaz Hrahsheh, José A. Hoyos, Rajesh Narayanan, Thomas Vojta
Physics Faculty Research & Creative Works
We study the ground-state phase diagram of the Ashkin-Teller random quantum spin chain by means of a generalization of the strong-disorder renormalization group. In addition to the conventional paramagnetic and ferromagnetic (Baxter) phases, we find a partially ordered phase characterized by strong randomness and infinite coupling between the colors. This unusual phase acts, at the same time, as a Griffiths phase for two distinct quantum phase transitions, both of which are of infinite-randomness type. We also investigate the quantum multicritical point that separates the two-phase and three-phase regions, and we discuss generalizations of our results to higher dimensions and other …
Triply Differential (E,2e) Studies Of Phenol, Silva G. Da, R. F. Neves, L. Chiari, D. B. Jones, E. Ali, Don H. Madison, C. G. Ning, K. L. Nixon, M. C. Lopes, M. J. Brunger
Triply Differential (E,2e) Studies Of Phenol, Silva G. Da, R. F. Neves, L. Chiari, D. B. Jones, E. Ali, Don H. Madison, C. G. Ning, K. L. Nixon, M. C. Lopes, M. J. Brunger
Physics Faculty Research & Creative Works
We have measured (e,2e) triple differential cross sections (TDCS) for the electron-impact ionisation of phenol with coplanar asymmetrical kinematics for an incident electron energy of 250 eV. Experimental measurements of the angular distribution of the slow outgoing electrons at 20 eV are obtained when the incident electron scatters through angles of -5°, -10°, and -15°, respectively. The TDCS data are compared with calculations performed within the molecular 3-body distorted wave model. In this case, a mixed level of agreement, that was dependent on the kinematical condition being probed, was observed between the theoretical and experimental results in the binary peak …
Oscillons And Oscillating Kinks In The Abelian-Higgs Model, Charilaos Tsagkarakis, V. Achilleos, F. K. Diakonos, D. J. Frantzeskakis, G. C. Katsimiga, X. N. Maintas, E. Manousakis, A. Tsapalis
Oscillons And Oscillating Kinks In The Abelian-Higgs Model, Charilaos Tsagkarakis, V. Achilleos, F. K. Diakonos, D. J. Frantzeskakis, G. C. Katsimiga, X. N. Maintas, E. Manousakis, A. Tsapalis
Physics Faculty Research & Creative Works
We study the classical dynamics of the Abelian Higgs model employing an asymptotic multiscale expansion method, which uses the ratio of the Higgs to the gauge field amplitudes as a small parameter. We derive an effective nonlinear Schrödinger equation for the gauge field, and a linear equation for the scalar field containing the gauge field as a nonlinear source. This equation is used to predict the existence of oscillons and oscillating kinks for certain regimes of the ratio of the Higgs to the gauge field masses. Results of numerical simulations are found to be in very good agreement with the …
Interaction Of Positrons And Electrons With Atoms, Robert D. Dubois
Interaction Of Positrons And Electrons With Atoms, Robert D. Dubois
Physics Faculty Research & Creative Works
Progress in differential studies of ionization resulting from positron and electron impact being performed at the Missouri University of Science and Technology is described. Examples of doubly and triply (fully) differential single ionization data for the ejected electron and the scattered projectile channels are presented. Energy loss data for double ionization, plus estimates for the first-order interaction, shake off, SO, and TS1, are also presented.
Ion-Li Collision Dynamics Studied With A Motremi, J. Goullon, R. Hubele, A. Laforge, Michael Schulz, X. Wang
Ion-Li Collision Dynamics Studied With A Motremi, J. Goullon, R. Hubele, A. Laforge, Michael Schulz, X. Wang
Physics Faculty Research & Creative Works
In a novel experimental approach, a magneto-optical trap (MOT) is combined with a Reaction Microscope (ReMi) and implemented in an ion storage ring. Single ionization measurements were performed with 24 MeV O8+ and 6 MeV H+ projectiles and a state prepared lithium target. We obtained single-, double- and fully differential cross sections and observed features that we attribute to the structure and polarization of target initial states. © Published under license by IOP Publishing Ltd.
Search For Long-Lived Gravitational-Wave Transients Coincident With Long Gamma-Ray Bursts, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Search For Long-Lived Gravitational-Wave Transients Coincident With Long Gamma-Ray Bursts, J. Aasi, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
Long gamma-ray bursts (GRBs) have been linked to extreme core-collapse supernovae from massive stars. Gravitational waves (GW) offer a probe of the physics behind long GRBs. We investigate models of long-lived (∼10-1000 s) GW emission associated with the accretion disk of a collapsed star or with its protoneutron star remnant. Using data from LIGO's fifth science run, and GRB triggers from the Swift experiment, we perform a search for unmodeled long-lived GW transients. Finding no evidence of GW emission, we place 90% confidence-level upper limits on the GW fluence at Earth from long GRBs for three waveforms inspired by a …
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Weighing The Neutrino Mass Using The Galaxy Power Spectrum Of The Cmass Sample, Gong-Bo Zhao, Shun Saito, For Full List Of Authors, See Publisher's Website.
The Clustering Of Galaxies In The Sdss-Iii Baryon Oscillation Spectroscopic Survey: Weighing The Neutrino Mass Using The Galaxy Power Spectrum Of The Cmass Sample, Gong-Bo Zhao, Shun Saito, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
We measure the sum of the neutrino particle masses using the three-dimensional galaxy power spectrum of the Sloan Digital Sky Survey III (SDSS-III) Baryon Oscillation Spectroscopic Survey Data Release 9 the constant MASS (CMASS) galaxy sample. Combined with the cosmic microwave background, supernova and additional baryonic acoustic oscillation data, we find upper 95 per cent confidence limits (CL) of the neutrino mass ∑mν < 0.340 eV within a flat Λ cold dark matter (ΛCDM) background, and ∑mν< 0.821 eV, assuming a more general background cosmological model. The number of neutrino species is measured to be Neff = 4.308 ± 0.794 and 4.032+0.870 -0.894 for these two cases, respectively. We study and quantify the effect of several factors on the neutrino measurements, including the galaxy power spectrum bias model, the …
Light Sea Fermions In Electron-Proton And Muon-Proton Interactions, Ulrich D. Jentschura
Light Sea Fermions In Electron-Proton And Muon-Proton Interactions, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The proton radius conundrum [Pohl, Nature 466, 213 (2010)NATUAS0028-083610. 1038/nature09250 and Antognini, Science 339, 417 (2013)SCIEAS0036-807510.1126/ science.1230016] highlights the need to revisit any conceivable sources of electron-muon nonuniversality in lepton-proton interactions within the standard model. Superficially, a number of perturbative processes could appear to lead to such a nonuniversality. One of these is a coupling of the scattered electron into an electronic vacuum-polarization loop as opposed to a muonic one in the photon exchange of two valence quarks, which is present only for electron projectiles as opposed to muon projectiles. However, we show that this effect actually is part of …
Experimental And Theoretical Cross Sections For Molecular-Frame Electron-Impact Excitation-Ionization Of D₂, Julian C A Lower, Esam S M Ali, Susan M. Bellm, Erich Weigold, Allison L. Harris, Chuangang Ning, Don H. Madison
Experimental And Theoretical Cross Sections For Molecular-Frame Electron-Impact Excitation-Ionization Of D₂, Julian C A Lower, Esam S M Ali, Susan M. Bellm, Erich Weigold, Allison L. Harris, Chuangang Ning, Don H. Madison
Physics Faculty Research & Creative Works
We present both experimental and theoretical results for the dissociative ionization of D2 molecules induced by electron impact. Cross sections are determined in the molecular frame and are fully differential in the energies and emission angles of the dissociation fragments. Transitions are considered from the X1Σg+ electronic ground state of D2 to the 2sσg, 2pπu and 2pσu excited states of D2+. The experimental results are compared to calculations performed within the molecular four-body distorted-wave framework to describe the multicenter nature of the scattering process. The cross sections …