Open Access. Powered by Scholars. Published by Universities.®

Nuclear Commons™

Open Access. Powered by Scholars. Published by Universities.®

Physics Faculty Publications

Discipline
Institution
Keyword
Publication Year

Articles 301 - 330 of 400

Full-Text Articles in Nuclear

Two-Body Photodisintegration Of 3he Between 7 And 16 Mev, W. Tornow, H. J. Karwowski, J. H. Kelley, R. Raut, G. Rusev, S. C. Stave, A. P. Tonchev, A. Deltuva, A. C. Fonseca, L. E. Marcucci, R. Schiavilla Jan 2011

Two-Body Photodisintegration Of 3he Between 7 And 16 Mev, W. Tornow, H. J. Karwowski, J. H. Kelley, R. Raut, G. Rusev, S. C. Stave, A. P. Tonchev, A. Deltuva, A. C. Fonseca, L. E. Marcucci, R. Schiavilla

Physics Faculty Publications

A comprehensive data set is reported for the two-body photodisintegration cross section of 3He using mono-energetic photon beams at eleven energies between 7.0 and 16.0 MeV. A 3He + Xe high-pressure gas scintillator served as target and detector. Although our data are in much better agreement with our state-of-the-art theoretical calculations than the majority of the previous data, these calculations underpredict the new data by about 10%. This disagreement suggests an incomplete understanding of the dynamics of the three-nucleon system and its response to electromagnetic probes.

Go to article

Experimental Results In Dis, Sidis And Des From Jefferson Lab, Sebastian E. Kuhn Jan 2011

Experimental Results In Dis, Sidis And Des From Jefferson Lab, Sebastian E. Kuhn

Physics Faculty Publications

Jefferson Lab’s electron accelerator in its present incarnation, with a maximum beam energy slightly above 6 GeV, has already enabled a large number of experiments expanding our knowledge of nucleon and nuclear structure (especially in Deep Inelastic Scattering—DIS—at moderately high x, and in the resonance region). Several pioneering experiments have yielded first results on Deeply Virtual Compton Scattering (DVCS) and other Deep Exclusive Processes (DES), and the exploration of the rich landscape of transverse momentum‐dependent (TMD) structure functions using Semi‐Inclusive electron scattering (SIDIS) has begun. With the upgrade of CEBAF to 12 GeV now underway, a significantly larger kinematic …

Go to article

Short-Distance Structure Of Nuclei, D. W. Higinbotham, E. Piasetzky, L. Weinstein, S. A. Wood Jan 2011

Short-Distance Structure Of Nuclei, D. W. Higinbotham, E. Piasetzky, L. Weinstein, S. A. Wood

Physics Faculty Publications

One of Jefferson Lab's original missions was to further our understanding of the short-distance structure of nuclei, in particular, to understand what happens when two or more nucleons within a nucleus have strongly overlapping wave-functions – a phenomena commonly referred to as short-range correlations. Herein, we review the results of the (e, e'), (e, e'p) and (e, e'pN) reactions that have been used at Jefferson Lab to probe this short-distance structure as well as provide an outlook for future experiments.

Go to article

Scaling Properties At Freeze-Out In Relativistic Heavy-Ion Collisions, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, B. D. Anderson, S. Bueltmann, I. Koralt, D. Plyku, Star Collaboration Jan 2011

Scaling Properties At Freeze-Out In Relativistic Heavy-Ion Collisions, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, J. Alford, B. D. Anderson, S. Bueltmann, I. Koralt, D. Plyku, Star Collaboration

Physics Faculty Publications

Identified charged pion, kaon, and proton spectra are used to explore the system size dependence of bulk freeze-out properties in Cu+Cu collisions at √sNN=200 and 62.4 GeV. The data are studied with hydrodynamically motivated blast-wave and statistical model frameworks in order to characterize the freeze-out properties of the system. The dependence of freeze-out parameters on beam energy and collision centrality is discussed. Using the existing results from Au + Au and pp collisions, the dependence of freeze-out parameters on the system size is also explored. This multidimensional systematic study furthers our understanding of the QCD phase diagram revealing the importance …

Go to article

Measurement Of Single- And Double-Spin Asymmetries In Deep Inelastic Pion Electroproduction With A Longitudinally Polarized Target, H. Avakian, Gerard P. Gilfoyle, Et. Al. Dec 2010

Measurement Of Single- And Double-Spin Asymmetries In Deep Inelastic Pion Electroproduction With A Longitudinally Polarized Target, H. Avakian, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes φ have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q2. A significant nonzero sin2φ single spin asymmetry was observed for the first time indicating strong spin-orbit …

Go to article

Tensor Correlations Measured In 3He(E,E',Pp)N, H. Baghdasaryan, Gerard P. Gilfoyle, Et. Al. Nov 2010

Tensor Correlations Measured In 3He(E,E',Pp)N, H. Baghdasaryan, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We have measured the 3He(e, e', pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs by using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum ptot. For pair relative momenta between 0.3 and 0:5 GeV / c, the ratio is very small at low ptot and rises to approximately 0.5 at large ptot. This …

Go to article

Tensor Correlations Measured In 3he(E,E' Pp)N, H. Baghdasaryan, L. B. Weinstein, J. M. Laget, K. P. Adhikarii, M. Aghasyan, M. Amarian, M. Anghinolfi, H. Avakian, J. Ball, M. Battaglieri, R. P. Bennett, S. Bültmann, G. E. Dodge, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. Nepali, F. Sabatié, H. Seraydaryan, Z. W. Zhao Nov 2010

Tensor Correlations Measured In 3he(E,E' Pp)N, H. Baghdasaryan, L. B. Weinstein, J. M. Laget, K. P. Adhikarii, M. Aghasyan, M. Amarian, M. Anghinolfi, H. Avakian, J. Ball, M. Battaglieri, R. P. Bennett, S. Bültmann, G. E. Dodge, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. Nepali, F. Sabatié, H. Seraydaryan, Z. W. Zhao

Physics Faculty Publications

We have measured the 3He(e,e' pp)n reaction at an incident energy of 4.7 GeV over a wide kinematic range. We identified spectator correlated pp and pn nucleon pairs by using kinematic cuts and measured their relative and total momentum distributions. This is the first measurement of the ratio of pp to pn pairs as a function of pair total momentum ptot. For pair relative momenta between 0.3 and 0.5 GeV/c, the ratio is very small at low ptot and rises to approximately 0.5 at large ptot. This shows the dominance of tensor over …

Go to article

Absorption Of The Ω And Φ Mesons In Nuclei, M. Wood, Gerard P. Gilfoyle, Et. Al. Aug 2010

Absorption Of The Ω And Φ Mesons In Nuclei, M. Wood, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

Because of their long lifetimes, the ω and φ mesons are the ideal candidates for the study of possible modifications of the in-medium meson-nucleon interaction through their absorption inside the nucleus. During the E01-112 experiment at the Thomas Jefferson National Accelerator Facility, the mesons were photoproduced from 2H, C, Ti, Fe, and Pb targets. This Letter reports the first measurement of the ratio of nuclear transparencies for the e+e- channel. The ratios indicate larger in-medium widths compared with what have been reported in other reaction channels. The absorption of the ω meson is stronger than that …

Go to article

Differential Cross Sections And Recoil Polarizations For The Reaction Γp→K+Σ0, B. Dey, Gerard P. Gilfoyle, Et. Al. Aug 2010

Differential Cross Sections And Recoil Polarizations For The Reaction Γp→K+Σ0, B. Dey, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

High-statistics measurements of differential cross sections and recoil polarizations for the reaction γp → K+Σ0 have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies (√s) from 1.69 to 2.84 GeV, with an extensive coverage in the K+ production angle. Independent measurements were made using the K+pπ−(γ) and K+p(π−, γ ) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR, and LEPS results, while offering better statistical precision and …

Go to article

Differential Cross Sections And Recoil Polarizations For The Reaction Γp→K+Σ0, B. Dey, Gerard P. Gilfoyle, Et. Al. Aug 2010

Differential Cross Sections And Recoil Polarizations For The Reaction Γp→K+Σ0, B. Dey, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

High-statistics measurements of differential cross sections and recoil polarizations for the reaction γp → K+Σ0 have been obtained using the CLAS detector at Jefferson Lab. We cover center-of-mass energies ( √s) from 1.69 to 2.84 GeV, with an extensive coverage in the K+ production angle. Independent measurements were made using the K+pπ−(γ) and K+p(π−, γ) final-state topologies, and were found to exhibit good agreement. Our differential cross sections show good agreement with earlier CLAS, SAPHIR, and LEPS results, while offering better …

Go to article

Particle-Γ Spectroscopy Of The (P,D-Γ)155Gd Reaction: Neutron Single-Quasiparticle States At N=91, J. M. Allmond, C. W. Beausang, J. O. Rasmussen, T. J. Ross, M. S. Basunia, L. A. Bernstein, D. L. Bleuel, W. Brooks, N. Brown, J. T. Burke, B. Darakchieva, K. Dudziak, K. E. Evans, P. Fallon, H. B. Jeppesen, J. Leblanc, S. R. Lesher, M. A. Mcmahan, D. A. Meyer, L. Phair, N. D. Scielzo, S. R. Stroberg, M. Wiedeking Jun 2010

Particle-Γ Spectroscopy Of The (P,D-Γ)155Gd Reaction: Neutron Single-Quasiparticle States At N=91, J. M. Allmond, C. W. Beausang, J. O. Rasmussen, T. J. Ross, M. S. Basunia, L. A. Bernstein, D. L. Bleuel, W. Brooks, N. Brown, J. T. Burke, B. Darakchieva, K. Dudziak, K. E. Evans, P. Fallon, H. B. Jeppesen, J. Leblanc, S. R. Lesher, M. A. Mcmahan, D. A. Meyer, L. Phair, N. D. Scielzo, S. R. Stroberg, M. Wiedeking

Physics Faculty Publications

A segmented Si telescope and HPGe array is used to study the 156Gd(p,d-γ)155Gd direct reaction by d-γ and d-γ-γ coincidence measurements using 25-MeV protons. The present investigation is the first time that this N = 91 nucleus and the N = 90 region—which is known for a rapid change from vibrational to rotational character, several low-lying 0+ states in the even-even nuclei, and large Coriolis (ΔΩ = 1) plus ΔN = 2 mixing in the even-odd nuclei—have been studied by particle-γ coincidence following a direct reaction with light ions. Gamma-ray energies and branches, …

Go to article

Measurement Of Γ-Emission Branching Ratios For 154,156,158Gd Compound Nuclei: Tests Of Surrogate Nuclear Reaction Approximations For (N,Γ) Cross Sections, N. D. Scielzo Mar 2010

Measurement Of Γ-Emission Branching Ratios For 154,156,158Gd Compound Nuclei: Tests Of Surrogate Nuclear Reaction Approximations For (N,Γ) Cross Sections, N. D. Scielzo

Physics Faculty Publications

The surrogate nuclear reaction method can be used to determine neutron-induced reaction cross sections from measured decay properties of a compound nucleus created using a different reaction and calculated formation cross sections. The reliability of (n,γ) cross sections determined using the Weisskopf-Ewing and ratio approximations are explored for the 155, 157Gd(n,γ) reactions. Enriched gadolinium targets were bombarded with 22-MeV protons and γ rays were detected in coincidence with scattered protons using the Silicon Telescope Array for Reaction Studies/Livermore-Berkeley Array for Collaborative Experiments (STARS/LiBerACE) silicon and germanium detector arrays. The γ-emission probabilities for the 154, 156, …

Go to article

High-Energy Amplitudes In N= 4 Sym In The Next-To-Leading Order, Ian Balitsky, Giovanni A. Chirilli Mar 2010

High-Energy Amplitudes In N= 4 Sym In The Next-To-Leading Order, Ian Balitsky, Giovanni A. Chirilli

Physics Faculty Publications

The high-energy behavior of the N = 4 SYM amplitudes in the Regge limit can be calculated order by order in perturbation theory using the high-energy operator expansion in Wilson lines. At large Nc , a typical four-point amplitude is determined by a single BFKL pomeron. The conformal structure of the four-point amplitude is fixed in terms of two functions: pomeron intercept and the coefficient function in front of the pomeron (the product of two residues). The pomeron intercept is universal while the coefficient function depends on the correlator in question. The intercept is known in the first two orders …

Go to article

Differential Cross Section And Recoil Polarization Measurements For The Γp→K+Λ Reaction Using Clas At Jefferson Lab, M. E. Mccracken, Gerard P. Gilfoyle, Et. Al. Feb 2010

Differential Cross Section And Recoil Polarization Measurements For The Γp→K+Λ Reaction Using Clas At Jefferson Lab, M. E. Mccracken, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We present measurements of the differential cross section and 'B; recoil polarization for the γp → K+Λ reaction made using the CLAS detector at Jefferson Lab. These measurements cover the center-of-mass energy range from 1.62 to 2.84 GeV and a wide range of center-of-mass K+ production angles. Independent analyses were performed using the K+pπ− and K+p (missing π−) final-state topologies; results from these analyses were found to exhibit good agreement. These differential-cross-section measurements show excellent agreement with previous CLAS and LEPS results and offer increased precision and a 300-MeV increase …

Go to article

Fission Fragment Isomers Populated Via 6Li+232Th., J. J. Ressler, J. A. Caggiano, C. J. Francy, P. N. Peplowski, J. M. Allmond, C. W. Beausang, L. A. Bernstein, D. L. Bleuel, J. T. Burke, P. Fallon, A. A. Hecht, D. V. Jordan, S. R. Lesher, M. A. Mcmahan, T. S. Palmer, L. Phair, N. D. Scielzo, P. G. Swearingen, G. A. Warren, M. Wiedeking Jan 2010

Fission Fragment Isomers Populated Via 6Li+232Th., J. J. Ressler, J. A. Caggiano, C. J. Francy, P. N. Peplowski, J. M. Allmond, C. W. Beausang, L. A. Bernstein, D. L. Bleuel, J. T. Burke, P. Fallon, A. A. Hecht, D. V. Jordan, S. R. Lesher, M. A. Mcmahan, T. S. Palmer, L. Phair, N. D. Scielzo, P. G. Swearingen, G. A. Warren, M. Wiedeking

Physics Faculty Publications

Short-lived isomers in fission fragments following bombardment of 45-MeV 6Li on 232Th were examined. Isomers in the A ~ 95,122, and 132 mass regions were observed. New isomeric decays were observed in 121In [T1/2=17(2) μs], 123In (T1/2≳100 μs), and 125Sb [T1/2=25(4) μs]. These isomers are suggested to arise from ν(h11/2⊗d3/2)7−and ν(h11/2⊗s1/2)5− neutron core excitations coupling with the valence proton.

Go to article

Measurement Of Single- And Double-Spin Asymmetries In Deep Inelastic Pion Electroproduction With A Longitudinally Polarized Target, H. Avakian, P. Bosted, V. D. Burkert, L. Elouadrhiri, K. P. Adhikari, M. Aghasyan, M. Amaryan, M. Anghinolfi, H. Baghdasaryan, J. Ball, G. Dodge, G. Gavalian, N. Guler, A. Klein, S E. Kuhn, D. Martinez, M. R. Niroula, F. Sabatié, H. Seraydaryan, S. Tkachenko, L. B. Weinstein Jan 2010

Measurement Of Single- And Double-Spin Asymmetries In Deep Inelastic Pion Electroproduction With A Longitudinally Polarized Target, H. Avakian, P. Bosted, V. D. Burkert, L. Elouadrhiri, K. P. Adhikari, M. Aghasyan, M. Amaryan, M. Anghinolfi, H. Baghdasaryan, J. Ball, G. Dodge, G. Gavalian, N. Guler, A. Klein, S E. Kuhn, D. Martinez, M. R. Niroula, F. Sabatié, H. Seraydaryan, S. Tkachenko, L. B. Weinstein

Physics Faculty Publications

We report the first measurement of the transverse momentum dependence of double-spin asymmetries in semi-inclusive production of pions in deep-inelastic scattering off the longitudinally polarized proton. Data have been obtained using a polarized electron beam of 5.7 GeV with the CLAS detector at the Jefferson Lab (JLab). Modulations of single spin asymmetries over the azimuthal angle between lepton scattering and hadron production planes ϕ have been measured over a wide kinematic range in Bjorken x and virtual photon squared four-momentum Q2. A significant nonzero sin2ϕ single spin asymmetry was observed for the first time indicating strong spin-orbit correlations …

Go to article

Longitudinal Scaling Property Of The Charge Balance Function In Au + Au Collisions At √Snn= 200 Gev, B. I. Abelev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, B. D. Anderson, D. Arkhipkin, G. S. Averichev, J. Balewski, L. S. Barnby, S. Bültmann, I. Koralt, D. Plyku Jan 2010

Longitudinal Scaling Property Of The Charge Balance Function In Au + Au Collisions At √Snn= 200 Gev, B. I. Abelev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, I. Alekseev, B. D. Anderson, D. Arkhipkin, G. S. Averichev, J. Balewski, L. S. Barnby, S. Bültmann, I. Koralt, D. Plyku

Physics Faculty Publications

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at √sNN = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [ − 1.3 , 1.3 ] . The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width …

Go to article

Parton Energy Loss In Heavy-Ion Collisions Via Direct-Photon And Charged-Particle Azimuthal Correlations, B. I. Abelev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, B. D. Anderson, D. Arkhipkin, G. S. Averichev, S. Bueltmann, I. Koralt, Star Collaboration Jan 2010

Parton Energy Loss In Heavy-Ion Collisions Via Direct-Photon And Charged-Particle Azimuthal Correlations, B. I. Abelev, M. M. Aggarwal, Z. Ahammed, A. V. Alakhverdyants, B. D. Anderson, D. Arkhipkin, G. S. Averichev, S. Bueltmann, I. Koralt, Star Collaboration

Physics Faculty Publications

Charged-particle spectra associated with direct photon Ydir) and π0 are measured in p+p and Au+Au collisions at center-of-mass energy √sNN=200 GeV with the STAR detector at the Relativistic Heavy Ion Collider. A shower-shape analysis is used to partially discriminate between Ydirand π0. Assuming no associated charged particles in the γdir direction (near side) and small contribution from fragmentation photons (Yfrag), the associated charged-particle yields opposite to Ydir(away side) are extracted. In central Au+Au collisions, the charged-particle yields at midrapidity (|η|<1) and high transverse momentum (3 < PTassoc < 16 GeV/c) associated with γdir and π0 (|η|<0.9, 8 < PTtrig <16 GeV/c) are suppressed by a factor of 3–5 compared with p+p collisions. The observed suppression of the associated charged particles is similar for Ydir and π0 and …

Go to article

Electromagnetic Structure And Reactions Of Few-Nucleon Systems In Χeft, L. Girlanda, S. Pastore, R. Schiavilla, M. Viviani Jan 2010

Electromagnetic Structure And Reactions Of Few-Nucleon Systems In Χeft, L. Girlanda, S. Pastore, R. Schiavilla, M. Viviani

Physics Faculty Publications

We summarize our recent work dealing with the construction of the nucleon-nucleon potential and associated electromagnetic currents up to one loop in chiral effective field theory (χEFT). The magnetic dipole operators derived from these currents are then used in hybrid calculations of static properties and low-energy radiative capture processes in few-body nuclei. A preliminary set of results are presented for the magnetic moments of the deuteron and trinucleons and thermal neutron captures on p, d, and ³He.

Go to article

Hard Photodisintegration Of A Proton Pair, I. Pomerantz, N. Bubis, K. Allada, A. Beck, B. L. Berman, W. Boeglin, A. Camsonne, M. Canan, K. Chirapatpimol, E. Cisbani Jan 2010

Hard Photodisintegration Of A Proton Pair, I. Pomerantz, N. Bubis, K. Allada, A. Beck, B. L. Berman, W. Boeglin, A. Camsonne, M. Canan, K. Chirapatpimol, E. Cisbani

Physics Faculty Publications

We present a study of high energy photodisintegration of proton-pairs through the γ + 3He → p + p + n channel. Photon energies, Eγ , from 0.8 to 4.7 GeV were used in kinematics corresponding to a proton pair with high relative momentum and a neutron nearly at rest. The s−11 scaling of the cross section, as predicted by the constituent counting rule for two nucleon photodisintegration, was observed for the first time. The onset of the scaling is at a higher energy and the cross section is significantly lower than for deuteron (pn pair) photodisintegration. …

Go to article

Differential Cross Sections And Spin Density Matrix Elements For The Reaction Γp→Pω, M. Williams, Gerard P. Gilfoyle, Et. Al. Dec 2009

Differential Cross Sections And Spin Density Matrix Elements For The Reaction Γp→Pω, M. Williams, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

High-statistics differential cross sections and spin-density matrix elements for the reaction γp → pω have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass (c.m.) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide c.m. energy bins, each subdivided into cos θωc.m. bins of width 0.1. These are the most precise and extensive ω photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

Go to article

Partial Wave Analysis Of The Reaction Γp→Pω And The Search For Nucleon Resonances, M. Williams, Gerard P. Gilfoyle, Et. Al. Dec 2009

Partial Wave Analysis Of The Reaction Γp→Pω And The Search For Nucleon Resonances, M. Williams, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

An event-based partial wave analysis (PWA) of the reaction γp → pω has been performed on a high-statistics dataset obtained using the CLAS at Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This analysis benefits from access to the world’s first high-precision spin-density matrix element measurements, available to the event-based PWA through the decay distribution of ω → π +π −π0. The data confirm the dominance of the t-channel π0 exchange amplitude in the forward direction. The dominant resonance contributions are consistent with the previously identified states F15(1680) and …

Go to article

G Factor Of The 2+1 State Of 172Hf, Z. Berant, E. Oster, R. J. Casperson, A. Wolf, V. Werner, A. Heinz, R. F. Casten, G. Gurdal, E. A. Mccutchan, D. S. Brenner, J. R. Terry, R. Winkler, E. Williams, J. Qian, A. Schmidt, M. K. Smith, T. Ahn, C. W. Beausang, P. H. Regan, T. J. Ross, M. Bunce, B. Darakchieva, D. A. Meyer, J. Leblanc, K. Dudziak, C. Bauer, G. Henning Nov 2009

G Factor Of The 2+1 State Of 172Hf, Z. Berant, E. Oster, R. J. Casperson, A. Wolf, V. Werner, A. Heinz, R. F. Casten, G. Gurdal, E. A. Mccutchan, D. S. Brenner, J. R. Terry, R. Winkler, E. Williams, J. Qian, A. Schmidt, M. K. Smith, T. Ahn, C. W. Beausang, P. H. Regan, T. J. Ross, M. Bunce, B. Darakchieva, D. A. Meyer, J. Leblanc, K. Dudziak, C. Bauer, G. Henning

Physics Faculty Publications

The g factor of the 2+1 state of 172Hf was measured using the perturbed angular correlation technique in a static external magnetic field. The result, g(2+1) = 0.25(5), is discussed in relation to the systematics of the previously reported g factors in the Hf isotopes and compared with the predictions of several models. An interesting outcome of the analysis presented in this paper is the agreement between the calculated g factors within the interacting boson approximation (IBA) and the results of a large-scale shell model calculation. This agreement supports the emphasis in the …

Go to article

Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, I. G. Aznauryan, Gerard P. Gilfoyle, Et. Al. Nov 2009

Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, I. G. Aznauryan, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We present results on the electroexcitation of the low mass resonances ∆(1232)P33, N(1440)P11, N(1520)D13, and N(1535)S11 in a wide range of Q2. The results were obtained in the comprehensive analysis of data from the Continuous Electron Beam Accelerator Facility (CEBAF) large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility (JLab) on differential cross sections, longitudinally polarized beam asymmetries, and longitudinal target and beam-target asymmetries for π electroproduction off the proton. The data were analyzed using two conceptually different approaches—fixed-t dispersion …

Go to article

Differential Cross Sections For The Reactions Γp→Pη And Γp→Pη', M. Williams, Gerard P. Gilfoyle, Et. Al. Oct 2009

Differential Cross Sections For The Reactions Γp→Pη And Γp→Pη', M. Williams, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

High-statistics differential cross sections for the reactions γp → pη and γp → pη' have been measured using the CEBAF large acceptance spectrometer (CLAS) at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The η' results are the most precise to date and provide the largest energy and angular coverage. The η measurements extend the energy range of the world’s large-angle results by approximately 300 MeV. These new data, in particular the η' measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

Go to article

Photoproduction Of Π​+Π​- Meson Pairs On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al. Oct 2009

Photoproduction Of Π​+Π​- Meson Pairs On The Proton, M. Battaglieri, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

The exclusive reaction γp → pπ+π- was studied in the photon energy range 3.0–3.8 GeV and the momentum transfer range 0:4 < -t < 1:0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range, the integrated luminosity was about 20 pb-1. The reaction was isolated by detecting the π+ and proton in CLAS, and reconstructing the π- via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the S, P, and D …

Go to article

Photodisintegration Of 4He Into P + T, R. Nasseripour, Gerard P. Gilfoyle, Et. Al. Oct 2009

Photodisintegration Of 4He Into P + T, R. Nasseripour, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

The two-body photodisintegration of 4He into a proton and a triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. Real photons produced with the Hall-B bremsstrahlung-tagging system in the energy range from 0.35 to 1.55 GeV were incident on a liquid 4He target. This is the first measurement of the photodisintegration of 4He above 0.4 GeV. The differential cross sections for the γ 4He → pt reaction were measured as a function of photon-beam energy and proton-scattering angle and are compared with the latest model calculations by J.M. …

Go to article

Beam Spin Asymmetries In Deeply Virtual Compton Scattering (Dvcs) With Clas At 4.8 Gev, G. Gavalian, Gerard P. Gilfoyle, Et. Al. Sep 2009

Beam Spin Asymmetries In Deeply Virtual Compton Scattering (Dvcs) With Clas At 4.8 Gev, G. Gavalian, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

We report measurements of the beam spin asymmetry in deeply virtual Compton scattering (DVCS) at an electron beam energy of 4.8 GeV using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The DVCS beam spin asymmetry has been measured in a wide range of kinematics, 1.0 < Q2 < 2.8 (GeV/c)2, 0.12 < xB < 0.48, and 0.1 < −t < 0.8 (GeV/c)2, using the reaction ep → e' p X. The number of H(e, e' γ p) and H(e, e'π0p) events are separated in each (Q2, xB, t …

Go to article

High-K Multi-Quasiparticle States And Rotational Bands In 255103Lr., H. B. Jeppesen, R. M. Clark, K. E. Gregorich, A. V. Afanasjev, M. N. Ali, J. M. Allmond, C. W. Beausang, M. Cromaz, M. A. Deleplanque, I. Dragojevic, J. Dvorak, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, S. Gros, I. Y. Lee, A. O. Macchiavelli, S. L. Nelson, H. Nitsche, L. Stavsetra, F. S. Stephens, M. Wiedeking Aug 2009

High-K Multi-Quasiparticle States And Rotational Bands In 255103Lr., H. B. Jeppesen, R. M. Clark, K. E. Gregorich, A. V. Afanasjev, M. N. Ali, J. M. Allmond, C. W. Beausang, M. Cromaz, M. A. Deleplanque, I. Dragojevic, J. Dvorak, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, S. Gros, I. Y. Lee, A. O. Macchiavelli, S. L. Nelson, H. Nitsche, L. Stavsetra, F. S. Stephens, M. Wiedeking

Physics Faculty Publications

Two isomeric states have been identified in 255Lr. The decay of the isomers populates rotational structures. Comparison with macroscopic-microscopic calculations suggests that the lowest observed sequence is built upon the [624]9/2+ Nilsson state. However, microscopic cranked relativistic Hartree-Bogoliubov (CRHB) calculations do not reproduce the moment of inertia within typical accuracy. This is a clear challenge to theories describing the heaviest elements.

Go to article

Π+ Photoproduction On The Proton For Photon Energies From 0.725 To 2.875 Gev, M. Dugger, Gerard P. Gilfoyle, Et. Al. Jun 2009

Π+ Photoproduction On The Proton For Photon Energies From 0.725 To 2.875 Gev, M. Dugger, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

Differential cross sections for the reaction γp → nπ+ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID andMAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the …

Go to article

First Prev Next Last