Physical Sciences and Mathematics Commons^™

Measurement Of The Helicity Asymmetry E For The 𝛾p → P𝛑⁰ Reaction In The Resonance Region, C. W. Kim, N. Zachariou, M. Bashkanov, W. J. Briscoe, S. Fegan, V. L. Kashevarov, K. Nikonov, A. Sarantsev, A. Schmidt, I. I. Strakovsky, D. P. Watts, R. L. Workman, P. Achenbach, Z. Akbar, M. J. Amaryan, G. Angelini, W. R. Armstrong, H. Atac, L. Baashen, M. Zurek, Et Al., The Clas Collaboration

Physics Faculty Publications

The double-spin-polarization observable E for 𝛾^→ p^→ → p𝛑⁰ has been measured with the CEBAF Large Acceptance Spectrometer (CLAS) at photon beam energies E𝛾 from 0.367 to 2.173 GeV (corresponding to center-of-mass energies from 1.240 to 2.200 GeV) for pion center-of-mass angles, cos θ^c.m._𝛑⁰, between - 0.86 and 0.82. These new CLAS measurements cover a broader energy range and have smaller uncertainties compared to previous CBELSA data and provide an important independent check on systematics. These measurements are compared to predictions as well as new global fits from The George Washington University, Mainz, and Bonn-Gatchina …

Measurement Of Spin-Density Matrix Elements In P(770) Production With A Linearly Polarized Photon Beam At E𝛾 = 8.2-8.8 Gev, S. Adhikari, F. Afzal, C. S. Akondi, M. Albrecht, M. Amaryan, V. Arroyave, A. Asaturyan, A. Austregesilo, Z. Baldwin, F. Barbosa, J. Barlow, E. Barriga, R. Barsotti, T. D. Beattie, V. V. Berdnikov, T. Black, W. Boeglin, W. J. Briscoe, T. Britton, B. Zihlmann, Et Al., Gluex Collaboration

Physics Faculty Publications

The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized 8.5 GeV photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson ρ(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of s-channel helicity conservation at small squared four-momentum transfer t and are able to extract the t dependence of natural- and unnatural-parity exchange contributions to …

Tools For Predicting Emulsification Capacity Of Crude Oil Exposed To Sunlight: Impact Of Photoproduced Carboxylic Acids On Emulsion Stability, Chaka Nacaya Brown

University of New Orleans Theses and Dissertations

The role of acids in the formation of emulsions from sunlight exposed petroleum is not well understood. To elucidate the impact of sunlight on the formation of emulsions from petroleum, Macondo, its surrogate and NIST 1619b and 2717a were separately exposed to simulated sunlight for up to 48 hours as a film dispersed into a quartz dish, or a film spread on water. Emulsion stability was scored from 0-5. All exposures demonstrated a correlation between emulsion stability and sunlight exposure with no observable emulsification in absence of photoproduction due to sunlight exposure. Aqueous studies of DOC_HC (dissolved organic carbon …

J/Ψ Photoproduction Near Threshold With Clas12, Joseph Newton

Physics Theses & Dissertations

The structure of the proton is comprised of quarks and a sea of gluons. A mechanism that can extract the characteristics of the hidden-color correlations of the nuclear wavefunction is the production of charm near threshold. Due to the fact that momentum transfer is large near threshold in the production of J/ψ , all three valence quarks must act coherently to ex- change energy for the reaction to occur. Models have been developed to predict the nature of J/ψ photoproduction at these specific energies. These include production mechanisms with the two-gluon and three-gluon exchanges. The transferred momentum dependence of the …

Beam-Target Helicity Asymmetry E In K 0 Λ And K 0 Σ 0 Photoproduction On The Neutron, D. H. Ho, R. A.. Schumacher, A. D' Angelo, A. Deur, J. Fleming, C. Hanretty, K. P. Adhikari, D. Adikaram, M. Khachatryan, A. Klein, M. Meyer, L. B. Weinstein, The Class Collaboration

Physics Faculty Publications

We report the first measurements of the E beam-target helicity asymmetry for the →γ→n→K⁰Λ and K⁰Σ⁰ channels in the energy range 1.70 ≤ W ≤ 2.34 GeV. The CLAS system at Jefferson Lab uses a circularly polarized photon beam and a target consisting of longitudinally polarized solid molecular hydrogen deuteride with low background contamination for the measurements. The multivariate analysis method boosted decision trees is used to isolate the reactions of interest. Comparisons with predictions from the KaonMAID, SAID, and Bonn-Gatchina models are presented. These results will help separate the isospin I=0 and I …

Measurements Of The Gamma(Upsilon)P -> P ’Pi(+)Pi(- )Cross Section With The Clas Detector For 0.4 Gev2 < Q(2) < 1.0 Gev2 And 1.3 Gev < W < 1.825 Gev, G. Fedotov, Iu A. Skorodumina, V. D. Burkert, R. W. Gothe, K. Hicks, V. Mokeev, S. Adhikari, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

New results on the single-differential and fully integrated cross sections for the process γ_vp -> p'π⁺π^- are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass W from 1.3 to 1.825 GeV and the photon virtuality Q² from 0.4 to 1.0 GeV². The cross sections were obtained in narrow Q² bins (0.05 GeV²) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in …

First Measurement Of Ξ− Polarization In Photoproduction, J. Bono, L. Guo, K. P. Adhikari, M. J. Amaryan, G. Charles, G. Gavalian, M. Khachatryan, A. Klein, Y. Prok, J. Zhang, Z. W. Zhao

Physics Faculty Publications

Despite decades of studies of the photoproduction of hyperons, both their production mechanisms and their spectra of excited states are still largely unknown. While the parity-violating weak decay of hyperons offers a means of measuring their polarization, which could help discern their production mechanisms and identify their excitation spectra, no such study has been possible for doubly strange baryons in photoproduction, due to low production cross sections. However, by making use of the reaction γ p → K⁺K⁺Ξ−, we have measured, for the first time, the induced polarization, P, and the transferred polarization from circularly polarized …

Measurements Of The Γv P → P'Π+Π− Cross Section With The Clas Detector For 0.4 Gev2 < Q2 < 1.0 Gev2 And 1.3 Gev < W < 1.825 Gev, G. V. Fedotov, Iu. A. Skorodumina, V. D. Burkert, R. W. Gothe, G. Charles, M. Khachatryan, A. Klein, Y. Prok, Z. W. Zhao, Clas Collaboration

Physics Faculty Publications

New results on the single-differential and fully integrated cross sections for the process γ_vp → p'π+π− are presented. The experimental data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the kinematic region of the reaction invariant mass W from 1.3 to 1.825 GeV and the photon virtuality Q² from 0.4 to 1.0 GeV². The cross sections were obtained in narrow Q² bins (0.05 GeV²) with the smallest statistical uncertainties achieved in double-pion electroproduction experiments to date. The results were found to be in agreement with previously …

Photoproduction And Radiative Decay Of Ηt Meson In Clas At Jlab, Georgie Mbianda Njencheu

Physics Theses & Dissertations

In this work the η/ meson photoproduction cross sections as well as the distribution of the di-pion invariant mass, m(π+π−), in the radiative decay mode η/ → π+π−γ have been measured using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photons in the center-of-mass energy range 1.96 GeV - 2.72 GeV. The measurements are performed on a liquid hydrogen target in the reaction γp → pη/(η/ → π+π−γ). The analysis is based on the …

The Beam-Helicity Asymmetry For Two Pseudoscalar Mesons In Photoproduction And A Partial Wave Analysis For Excited Hyperons, Rafael A. Badui

FIU Electronic Theses and Dissertations

The first-time measurement of the angular dependence of the beam-helicity asymmetry for $\gamma p \rightarrow pK^{+}K^{-}$ is shown and compared to $\gamma p \rightarrow p\pi^{+}\pi^{-}$. The data obtained were from the CLAS g12 experiment at Jefferson Lab. The experiment utilized a beam of circularly polarized photons with energies between 1.1 and 5.4 GeV incident on an unpolarized liquid hydrogen target, which produced an unprecedented number of strange hadrons in photoproduction. The production mechanism for strange hadrons is not well understood. The beam-helicity asymmetry is a polarization observable that provides information on interfering production mechanisms in the reaction. It is shown …

The Gluex Start Counter & Beam Asymmetry $\Sigma$ In Single $\Pi^{0}$ Photoproduction, Eric J. Pooser

FIU Electronic Theses and Dissertations

The GlueX experiment aims to study meson photoproduction while utilizing the coherent bremsstrahlung technique to produce a 9 GeV linearly polarized photon beam incident on a liquid $\mathrm{H_{2}}$ target. A Start Counter detector was fabricated to properly identify the accelerator electron beam buckets and to provide accurate timing information. The Start Counter detector was designed to operate at photon intensities of up to $\mathrm{10^{8}\gamma/s}$ in the coherent peak and provides a timing resolution $\mathrm{\sim 300\ ps}$ so as to provide successful identification of the electron beam buckets to within 99\% accuracy. Furthermore, the Start Counter detector provides excellent solid angle …

Electroexcitation Of The Δ+ (1232) At Low Momentum Transfer, A. Blomberg, D. Anez, N. Sparveris, A. J. Sarty, M. Paolone, S. Gilad, D. Higinbotham, Z. Ahmed, H. Albataineh, K. Allada

Physics Faculty Publications

We report on new p(e, e' p)π°. measurements at the Δ⁺(1232) resonance at the low momentum transfer region, where the mesonic cloud dynamics is predicted to be dominant and rapidly changing, offering a test bed for chiral effective field theory calculations. The new data explore the Q² dependence of the resonant quadrupole amplitudes and for the first time indicate that the Electric and the Coulomb quadrupole amplitudes converge as Q² -> 0. The measurements of the Coulomb quadrupole amplitude have been extended to the lowest momentum transfer ever reached, and suggest that more than half of …

Measurements Of Ep → E'Π+N At 1.6 < W <2.0 Gev And Extraction Of Nucleon Resonance Electrocouplings At Clas, The Clas Collaboration, K. Park, K. P. Adhikari, M. J. Amaryan, L. El Fassi, Y. Prok, L. B. Weinstein

Physics Faculty Publications

Differential cross sections of the exclusive process ep -> e 'π⁺n were measured with good precision in the range of the photon virtuality Q² = 1.8-4.5 GeV² and the invariant mass range of the π⁺n final state W = 1.6-2.0 GeV using the Continuous Electron Beam Accelerator Facility Large Acceptance Spectrometer. Data were collected with nearly complete coverage in the azimuthal and polar angles of the n π⁺center-of-mass system. More than 37 000 cross-section points were measured. The contributions of the isospin I = ½ resonances N(1675) 5/2^-, N(1680) 5/2 …

Separated Response Functions In Exclusive, Forward Π± Electroproduction On Deuterium, G. M. Huber, H. P. Blok, A. Klein, L. M. Qin, K. Vansyoc, Jefferson Lab, Fπ Collaboration

Physics Faculty Publications

Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, Q², and at different four-momentum transfer, t, can be used to probe QCD's transition from meson-nucleon degrees of freedom at long distances to quark-gluon degrees of freedom at short scales. Ratios of separated response functions in π^- and π⁺ electroproduction are particularly informative. The ratio for transverse photons may allow this transition to be more easily observed, while the ratio for longitudinal photons provides a crucial verification of the assumed pole dominance, needed for reliable extraction of the pion form …

First Measurement Of The Polarization Observable E In The P→ (Ɣ→, Π+) In Reaction Up To 2.25 Gev, S. Strauch, W. J. Briscoe, M. Döring, E. Klempt, V. A. Nikonov, E. Pasyuk, D. Rönchen, A.V. Sarantsev, I. Strakovsky, R. Workman, K. P. Adhikari, D. Adikaram, L. El Fassi

Physics Faculty Publications

First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction ɣ^→p^→→π+n, has been measured using a circularly polarized tagged-photon beam, with energies from 0.35 to 2.37 GeV. The final-state pions were detected with the CEBAF Large Acceptance Spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility. These polarization data agree fairly well with previous partial-wave analyses at low photon energies. Over much of the covered energy range, however, significant deviations are observed, particularly in the high-energy region where high-L multipoles contribute. The data have been …

Separated Response Function Ratios In Exclusive, Forward Π± Electroproduction, G. M. Huber, H. P. Blok, C. Butuceanu, D. Gaskell, T. Horn, D. J. Mack, D. Abbott, A. Klein, L. M. Qin, K. Vansyoc

Physics Faculty Publications

The study of exclusive π^± electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio R-L=sigma(pi-)(L) / sigma(pi+)(L) is sensitive to isoscalar contamination to the dominant isovector pion exchange amplitude, which is the basis for the determination of the charged pion form factor from electroproduction data. A change in the value of R-T=sigma(pi-)(L) / sigma(pi+)(L) from unity at small -t, to 1/4 at large -t, would suggest a transition from coupling to a (virtual) pion to coupling to individual quarks. Furthermore, the mentioned ratios may show an earlier …

Estimating Hydroxyl Radical Photochemical Formation Rates In Natural Waters During Long-Term Laboratory Irradiation Experiments, Luni Sun, Hongmei Chen, Hussain A. Abdulla, Kenneth Mopper

Chemistry & Biochemistry Faculty Publications

In this study it was observed that, during long-term irradiations (>1 day) of natural waters, the methods for measuring hydroxyl radical (˙OH) formation rates based upon sequentially determined cumulative concentrations of photoproducts from probes significantly underestimate actual ˙OH formation rates. Performing a correction using the photodegradation rates of the probe products improves the ˙OH estimation for short term irradiations (<1 day), but not long term irradiations. Only the ‘instantaneous’ formation rates, which were obtained by adding probes to aliquots at each time point and irradiating these sub-samples for a short time (≤2 h), were found appropriate for accurately estimating ˙OH photochemical formation rates during long-term laboratory irradiation experiments. Our results also showed that in iron- and dissolved organic matter (DOM)-rich water samples, ˙OH appears to be mainly produced from the Fenton reaction initially, but subsequently from other sources possibly from DOM photoreactions. Pathways of ˙OH formation in long-term irradiations in relation to H2O2 and iron concentrations are discussed.

Photoproduction Of Π0 On Hydrogen With Clas From 1.1 Gev - 5.45 Gev Using E+E –Γ Decay, Michael C. Kunkel

Physics Theses & Dissertations

Photoproduction of the π⁰ meson was studied using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photon energies spanning the range E_γ = 1.1 GeV - 5.45 GeV. The measurement is performed on a liquid hydrogen target in the reaction γp → pe ⁺e^–(γ). The final state of the reaction is the sum of two subprocesses for π⁰ decay, the Dalitz decay mode of π⁰ → e ⁺e^–γ and conversion mode where one photon from π⁰ → γγ decay is converted into a …

Photoproduction Of Ammonium In The Southeastern Beaufort Sea And Its Biogeochemical Implications, H. Xie, S. Belanger, G. Song, Ronald Benner, A. Taalba, M. Blais, J. É. Tremblay, M. Babin

Faculty Publications

Photochemistry of dissolved organic matter (DOM) plays an important role in marine biogeochemical cycles, including the regeneration of inorganic nutrients. DOM photochemistry affects nitrogen cycling by converting bio-refractory dissolved organic nitrogen to labile inorganic nitrogen, mainly ammonium (NH₄⁺).During the August 2009 Mackenzie Light and Carbon (MALINA) Program, the absorbed photon-based efficiency spectra of NH₄⁺ photoproduction (i.e. photoammonification) were determined using water samples from the SE Beaufort Sea, including the Mackenzie River estuary, shelf, and Canada Basin. The photoammonification efficiency decreased with increasing wavelength across the ultraviolet and visible regimes and was higher in offshore waters …

Measurement Of The Energy Dependence Of The Total Photon-Proton Cross Section At Hera, H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bold, E. G. Boos, K. Borras, Margarita C. K. Mattingly

Faculty Publications

The energy dependence of the photon-proton total cross section, σtotγp, was determined from e+p scattering data collected with the ZEUS detector at HERA at three values of the center-of-mass energy, W, of the γp system in the range 194

Photoproduction Of The Φ(1020) Meson In Neutral Decay Mode Γp → Φp → K(S)K(L)P, Heghine Seraydaryan

Physics Theses & Dissertations

The Φ(1020) meson photoproduction cross sections in the neutral decay mode Φ → K_SK_L are measured for the first time. This work presents measurements of differential cross sections, dσ/dt, dσ/d cos θ^Φ_c.m.; Φ decay angular distributions, W(cos θ) and W(Φ), and spin-density matrix elements, ρ⁰, in the Helicity and Gottfried-Jackson frames, in the energy range 1.6 GeV < E_γ < 2.6 GeV. We analyzed the photoproduction data of the g11a experiment collected on an LH2 target using the CLAS detectector at Hall B, TJNAF. The measured cross sections show some differences from the charged decay mode Φ → K⁺ K⁻.

Design Of Electronics For A High-Energy Photon Tagger For The Gluex Experiment, Mitchell "Woody" Underwood

Honors Scholar Theses

In quantum chromodynamics (QCD), quarks and antiquarks are held together inside hadrons by the nuclear strong force, which is mediated by exchange particles known as gluons. The simplest type of hadron, the meson, consists of a single quark and a single antiquark bound by a gluonic field. The flux-tube model of QCD says that this gluonic field forms a tube of color-electric field lines between the quark and the antiquark which can under the right conditions be made to vibrate. Such mesons with excited glue are called hybrid mesons.

GlueX is a high-energy nuclear physics experiment which will study hybrid …

Virtual Compton Scattering And Neutral Pion Electroproduction In The Resonance Region Up To The Deep Inelastic Region At Backward Angles, G. Laveissiere, N. Degrande, S. Jaminion, C. Jutier, L. Todor, G. E. Dodge, C. E. Hyde, K. Mccormick, P. E. Ulmer, L. B. Weinstein, Jefferson Lab Hall A Collaboration

Physics Faculty Publications

We have made the first measurements of the virtual Compton scattering (VCS) process via the H(e, e′p)γ exclusive reaction in the nucleon resonance region, at backward angles. Results are presented for the W-dependence at fixed Q²=1 GeV² and for the Q² dependence at fixed W near 1.5 GeV. The VCS data show resonant structures in the first and second resonance regions. The observed Q² dependence is smooth. The measured ratio of H(e, e′p)γ to H(e, e′p)π⁰ cross sections emphasizes the different sensitivity of these two reactions to the various nucleon resonances. Finally, when compared …

Electroexcitation Of Nucleon Resonances From Clas Data On Single Pion Electroproduction, Clas Collaboration, K. P. Adhikari, S. L. Careccia, T. A. Forest, C. E. Hyde, A. Klein, S. E. Kuhn, M. Mayer, C. S. Nepali, M. R. Niroula, H. Seraydaryan

Physics Faculty Publications

We present results on the electroexcitation of the low mass resonances Δ(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 relations and a unitary isobar model—allowing us to …

Three- And Four-Jet Final States In Photoproduction At Hera, S. Chekanov, M. Derrick, S. Magill, B. Musgrave, D. Nicholass, J. Repond, R. Yoshida, Margarita C. K. Mattingly, M. Jechow, N. Pavel, A. G. Yagües Molina, S. Antonelli, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, M. Bindi, D. Boscherini, A. Bruni, G. Bruni, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, G. Iacobucci, A. Margotti, R. Nania, A. Polini, G. Sartorelli, A. Zichichi

Faculty Publications

Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121 pb -1. The results are presented for jets with transverse energy E Tjet > 6 GeV and pseudorapidity | η jet | < 2.4, in the kinematic region given by the virtuality of the photon Q 2 < 1 GeV 2 and the inelasticity 0.2 ≤ y ≤ 0.85 and in two mass regions defined as 25 ≤ M n j < 50 GeV and M n j ≥ 50 GeV, where M n j is the invariant mass of the n-jet system. The four-jet photoproduction cross section has been measured for the first time and represents the highest-order process studied at HERA. Both the three- and four-jet cross sections have been compared with leading-logarithmic parton-shower Monte Carlo models, with and without multi-parton interactions. The three-jet cross sections have been compared to an O (α α s2) perturbative QCD calculation. © 2007 Elsevier B.V. All rights reserved.

Measurement Of Ep→Epπᵒ Beam Spin Asymmetries Above The Resonance Region, Clas Collaborative, M. J. Amaryan, H. Bagdasaryan, S. Bültmann, S. L. Careccia, K. V. Dharmawardane, G. E. Dodge, G. Gavalian, N. Guler, C. E. Hyde-Wright, N. Kalantarians, A. Klien, A. V. Klimenko, S. E. Kuhn, M. R. Niroula, S. Tkachenko, L. B. Weinstein, J. Zhang

Physics Faculty Publications

The beam spin asymmetry (BSA) in the exclusive reaction ^→ep→epπ0 was measured with the CEBAF 5.77 GeV polarized electron beam and Large Acceptance Spectrometer (CLAS). The x_B,Q²,t , and ϕ dependences of the π⁰ BSA are presented in the deep inelastic regime. The asymmetries are fitted with a sinϕ function and their amplitudes are extracted. Overall, they are of the order of 0.04–0.11 and roughly independent of t . This is the signature of a nonzero longitudinal-transverse interference. The implications concerning the applicability of a formalism based on generalized parton distributions, as well as …

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 _K^c.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.

First Measurement Of Transferred Polarization In The Exclusive →E P → E'K+ →Λ, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, L. B. Weinstein, J. Yun

Physics Faculty Publications

The first measurements of the transferred polarization for the exclusive ^→ep → e'K+ ^→Λ over right arrow reaction have been performed at Jefferson Laboratory using the CLAS spectrometer. A 2.567 GeV beam was used to measure the hyperon polarization over Q² from 0.3 to 1.5 (GeV/c)², W from 1.6 to 2.15 GeV, and over the full K⁺ center-of-mass angular range. Comparison with predictions of hadrodynamic models indicates strong sensitivity to the underlying resonance contributions. A nonrelativistic quark-model interpretation of our data suggests that the s ^-s quark pair is produced with spins predominantly …

Measurement Of Ep → E ' P Π⁺Π⁻ And Baryon Resonance Analysis, M. Bektasoglu, L. Ciciani, K. V. Dharmawardane, G. E. Dodge, T. A. Forest, C. E. Hyde-Wright, A. Klein, A. V. Klimenko, S. E. Kuhn, R. A. Niyazov, L. M. Qin, F. Sabatié, S. Stepanyan, L. B. Weinstein, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

The cross section for the reaction ep→ e'pπ⁺π^- was measured in the resonance region for 1.4 2 < 1.5 GeV²/c²using the CLAS detector at Jefferson Laboratory. The data show resonant structures not visible in previous experiments. The comparison of our data to a phenomenological prediction using available information on N* and Δ states shows an evident discrepancy. A better description of the data is obtained either by a sizable change of the properties of the P₁₃(1720) resonance or by introducing a new baryon state, not reported in published analyses.

Η Photoproduction On The Proton For Photon Energies From 0.75 To 1.95 Gev, M. Bektasoglu, K. V. Dharmawardane, G. E. Dodge, C. E. Hyde-Wright, A. Klein, S. E. Kuhn, S. Stepanyan, J. Yun, Et Al., Clas Collaboration

Physics Faculty Publications

Differential cross sections for γp→ηp have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W = 1.75  GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S₁₁ resonance with mass ∼1.8  GeV couples to the ηN channel.