A. Kelleher - The Jefferson Lab Hall A Collaboration

A. Kelleher
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A. Kelleher
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The Jefferson Lab Hall A Collaboration
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Nuclear Experiment (34)
 
High Energy Physics - Experiment (14)
 
High Energy Physics - Phenomenology (5)
 
General Relativity and Quantum Cosmology (3)
 
Physics - Accelerator Physics (3)
 
Physics - Instrumentation and Detectors (3)
 
Nuclear Theory (3)
 
High Energy Physics - Theory (1)
 
Astrophysics (1)
 
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Publications Authored By A. Kelleher

$[Background]$ Measurements of the neutron charge distribution are made difficult by the fact that, with no net charge, the neutron electric form factor, $G^n_E$, is generally much smaller than the magnetic form factor, $G^n_M$. In addition, measurements of these form factors must use nuclear targets which requires accurately accounting for nuclear effects. $[Method]$ The inclusive quasi-elastic reaction $^3\overrightarrow{\rm{He}}(\overrightarrow{e},e')$ was measured at Jefferson Lab. Read More

The proton is composed of quarks and gluons, bound by the most elusive mechanism of strong interaction called confinement. In this work, the dynamics of quarks and gluons are investigated using deeply virtual Compton scattering (DVCS): produced by a multi-GeV electron, a highly virtual photon scatters off the proton which subsequently radiates a high energy photon. Similarly to holography, measuring not only the magnitude but also the phase of the DVCS amplitude allows to perform 3D images of the internal structure of the proton. Read More

2017Feb
Affiliations: 1The Jefferson Lab Hall A Collaboration, 2The Jefferson Lab Hall A Collaboration, 3The Jefferson Lab Hall A Collaboration, 4The Jefferson Lab Hall A Collaboration, 5The Jefferson Lab Hall A Collaboration, 6The Jefferson Lab Hall A Collaboration, 7The Jefferson Lab Hall A Collaboration, 8The Jefferson Lab Hall A Collaboration, 9The Jefferson Lab Hall A Collaboration, 10The Jefferson Lab Hall A Collaboration, 11The Jefferson Lab Hall A Collaboration, 12The Jefferson Lab Hall A Collaboration, 13The Jefferson Lab Hall A Collaboration, 14The Jefferson Lab Hall A Collaboration, 15The Jefferson Lab Hall A Collaboration, 16The Jefferson Lab Hall A Collaboration, 17The Jefferson Lab Hall A Collaboration, 18The Jefferson Lab Hall A Collaboration, 19The Jefferson Lab Hall A Collaboration, 20The Jefferson Lab Hall A Collaboration, 21The Jefferson Lab Hall A Collaboration, 22The Jefferson Lab Hall A Collaboration, 23The Jefferson Lab Hall A Collaboration, 24The Jefferson Lab Hall A Collaboration, 25The Jefferson Lab Hall A Collaboration, 26The Jefferson Lab Hall A Collaboration, 27The Jefferson Lab Hall A Collaboration, 28The Jefferson Lab Hall A Collaboration, 29The Jefferson Lab Hall A Collaboration, 30The Jefferson Lab Hall A Collaboration, 31The Jefferson Lab Hall A Collaboration, 32The Jefferson Lab Hall A Collaboration, 33The Jefferson Lab Hall A Collaboration, 34The Jefferson Lab Hall A Collaboration, 35The Jefferson Lab Hall A Collaboration, 36The Jefferson Lab Hall A Collaboration, 37The Jefferson Lab Hall A Collaboration, 38The Jefferson Lab Hall A Collaboration, 39The Jefferson Lab Hall A Collaboration, 40The Jefferson Lab Hall A Collaboration, 41The Jefferson Lab Hall A Collaboration, 42The Jefferson Lab Hall A Collaboration, 43The Jefferson Lab Hall A Collaboration, 44The Jefferson Lab Hall A Collaboration, 45The Jefferson Lab Hall A Collaboration, 46The Jefferson Lab Hall A Collaboration, 47The Jefferson Lab Hall A Collaboration, 48The Jefferson Lab Hall A Collaboration, 49The Jefferson Lab Hall A Collaboration, 50The Jefferson Lab Hall A Collaboration, 51The Jefferson Lab Hall A Collaboration, 52The Jefferson Lab Hall A Collaboration, 53The Jefferson Lab Hall A Collaboration, 54The Jefferson Lab Hall A Collaboration, 55The Jefferson Lab Hall A Collaboration, 56The Jefferson Lab Hall A Collaboration, 57The Jefferson Lab Hall A Collaboration, 58The Jefferson Lab Hall A Collaboration, 59The Jefferson Lab Hall A Collaboration, 60The Jefferson Lab Hall A Collaboration, 61The Jefferson Lab Hall A Collaboration, 62The Jefferson Lab Hall A Collaboration, 63The Jefferson Lab Hall A Collaboration, 64The Jefferson Lab Hall A Collaboration, 65The Jefferson Lab Hall A Collaboration, 66The Jefferson Lab Hall A Collaboration, 67The Jefferson Lab Hall A Collaboration, 68The Jefferson Lab Hall A Collaboration, 69The Jefferson Lab Hall A Collaboration, 70The Jefferson Lab Hall A Collaboration, 71The Jefferson Lab Hall A Collaboration, 72The Jefferson Lab Hall A Collaboration, 73The Jefferson Lab Hall A Collaboration, 74The Jefferson Lab Hall A Collaboration, 75The Jefferson Lab Hall A Collaboration, 76The Jefferson Lab Hall A Collaboration, 77The Jefferson Lab Hall A Collaboration, 78The Jefferson Lab Hall A Collaboration, 79The Jefferson Lab Hall A Collaboration, 80The Jefferson Lab Hall A Collaboration, 81The Jefferson Lab Hall A Collaboration, 82The Jefferson Lab Hall A Collaboration, 83The Jefferson Lab Hall A Collaboration, 84The Jefferson Lab Hall A Collaboration, 85The Jefferson Lab Hall A Collaboration, 86The Jefferson Lab Hall A Collaboration, 87The Jefferson Lab Hall A Collaboration, 88The Jefferson Lab Hall A Collaboration, 89The Jefferson Lab Hall A Collaboration, 90The Jefferson Lab Hall A Collaboration, 91The Jefferson Lab Hall A Collaboration, 92The Jefferson Lab Hall A Collaboration, 93The Jefferson Lab Hall A Collaboration, 94The Jefferson Lab Hall A Collaboration, 95The Jefferson Lab Hall A Collaboration, 96The Jefferson Lab Hall A Collaboration, 97The Jefferson Lab Hall A Collaboration, 98The Jefferson Lab Hall A Collaboration

We report the first longitudinal/transverse separation of the deeply virtual exclusive $\pi^0$ electroproduction cross section off the neutron and coherent deuteron. The corresponding four structure functions $d\sigma_L/dt$, $d\sigma_T/dt$, $d\sigma_{LT}/dt$ and $d\sigma_{TT}/dt$ are extracted as a function of the momentum transfer to the recoil system at $Q^2$=1.75 GeV$^2$ and $x_B$=0. Read More

The charge and magnetic form factors, FC and FM, of 3He have been extracted in the kinematic range 25 fm-2 < Q2 < 61 fm-2 from elastic electron scattering by detecting 3He recoil nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility at Jefferson Lab. The measurements are indicative of a second diffraction minimum for the magnetic form factor, which was predicted in the Q2 range of this experiment, and of a continuing diffractive structure for the charge form factor. The data are in qualitative agreement with theoretical calculations based on realistic interactions and accurate methods to solve the three-body nuclear problem. Read More

2016Oct

The unpolarized semi-inclusive deep-inelastic scattering (SIDIS) differential cross sections in $^3$He($e,e^{\prime}\pi^{\pm}$)$X$ have been measured for the first time in Jefferson Lab experiment E06-010 performed with a $5.9\,$GeV $e^-$ beam on a $^3$He target. The experiment focuses on the valence quark region, covering a kinematic range $0. Read More

We present deeply virtual $\pi^0$ electroproduction cross-section measurements at $x_B$=0.36 and three different $Q^2$--values ranging from 1.5 to 2 GeV$^2$, obtained from experiment E07-007 that ran in the Hall A at Jefferson Lab. Read More

We report on the results of the E06-014 experiment performed at Jefferson Lab in Hall A, where a precision measurement of the twist-3 matrix element $d_2$ of the neutron ($d_{2}^{n}$) was conducted. This quantity represents the average color Lorentz force a struck quark experiences in a deep inelastic electron scattering event off a neutron due to its interaction with the hadronizing remnants. This color force was determined from a linear combination of the third moments of the spin structure functions $g_1$ and $g_2$ on $^{3}$He after nuclear corrections had been applied to these moments. Read More

We report on new p$(e,e^\prime p)\pi^\circ$ measurements at the $\Delta^{+}(1232)$ resonance at the low momentum transfer region. The mesonic cloud dynamics is predicted to be dominant and rapidly changing in this kinematic region offering a test bed for chiral effective field theory calculations. The new data explore the low $Q^2$ dependence of the resonant quadrupole amplitudes while extending the measurements of the Coulomb quadrupole amplitude to the lowest momentum transfer ever reached. Read More

We present final results on the photon electroproduction ($\vec{e}p\rightarrow ep\gamma$) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed resulting in photon electroproduction cross sections at new kinematic settings, for a total of 588 experimental bins. Read More

2015Feb

We report the measurement of beam-target double-spin asymmetries ($A_\text{LT}$) in the inclusive production of identified hadrons, $\vec{e}~$+$~^3\text{He}^{\uparrow}\rightarrow h+X$, using a longitudinally polarized 5.9 GeV electron beam and a transversely polarized $^3\rm{He}$ target. Hadrons ($\pi^{\pm}$, $K^{\pm}$ and proton) were detected at 16$^{\circ}$ with an average momentum $<$$P_h$$>$=2. Read More

2014Jun
Affiliations: 1The Jefferson Lab Hall A Collaboration, 2The Jefferson Lab Hall A Collaboration, 3The Jefferson Lab Hall A Collaboration, 4The Jefferson Lab Hall A Collaboration, 5The Jefferson Lab Hall A Collaboration, 6The Jefferson Lab Hall A Collaboration, 7The Jefferson Lab Hall A Collaboration, 8The Jefferson Lab Hall A Collaboration, 9The Jefferson Lab Hall A Collaboration, 10The Jefferson Lab Hall A Collaboration, 11The Jefferson Lab Hall A Collaboration, 12The Jefferson Lab Hall A Collaboration, 13The Jefferson Lab Hall A Collaboration, 14The Jefferson Lab Hall A Collaboration, 15The Jefferson Lab Hall A Collaboration, 16The Jefferson Lab Hall A Collaboration, 17The Jefferson Lab Hall A Collaboration, 18The Jefferson Lab Hall A Collaboration, 19The Jefferson Lab Hall A Collaboration, 20The Jefferson Lab Hall A Collaboration, 21The Jefferson Lab Hall A Collaboration, 22The Jefferson Lab Hall A Collaboration, 23The Jefferson Lab Hall A Collaboration, 24The Jefferson Lab Hall A Collaboration, 25The Jefferson Lab Hall A Collaboration, 26The Jefferson Lab Hall A Collaboration, 27The Jefferson Lab Hall A Collaboration, 28The Jefferson Lab Hall A Collaboration, 29The Jefferson Lab Hall A Collaboration, 30The Jefferson Lab Hall A Collaboration, 31The Jefferson Lab Hall A Collaboration, 32The Jefferson Lab Hall A Collaboration, 33The Jefferson Lab Hall A Collaboration, 34The Jefferson Lab Hall A Collaboration, 35The Jefferson Lab Hall A Collaboration, 36The Jefferson Lab Hall A Collaboration, 37The Jefferson Lab Hall A Collaboration, 38The Jefferson Lab Hall A Collaboration, 39The Jefferson Lab Hall A Collaboration, 40The Jefferson Lab Hall A Collaboration, 41The Jefferson Lab Hall A Collaboration, 42The Jefferson Lab Hall A Collaboration, 43The Jefferson Lab Hall A Collaboration, 44The Jefferson Lab Hall A Collaboration, 45The Jefferson Lab Hall A Collaboration, 46The Jefferson Lab Hall A Collaboration, 47The Jefferson Lab Hall A Collaboration, 48The Jefferson Lab Hall A Collaboration, 49The Jefferson Lab Hall A Collaboration, 50The Jefferson Lab Hall A Collaboration, 51The Jefferson Lab Hall A Collaboration, 52The Jefferson Lab Hall A Collaboration, 53The Jefferson Lab Hall A Collaboration, 54The Jefferson Lab Hall A Collaboration, 55The Jefferson Lab Hall A Collaboration, 56The Jefferson Lab Hall A Collaboration, 57The Jefferson Lab Hall A Collaboration, 58The Jefferson Lab Hall A Collaboration, 59The Jefferson Lab Hall A Collaboration, 60The Jefferson Lab Hall A Collaboration, 61The Jefferson Lab Hall A Collaboration, 62The Jefferson Lab Hall A Collaboration, 63The Jefferson Lab Hall A Collaboration, 64The Jefferson Lab Hall A Collaboration, 65The Jefferson Lab Hall A Collaboration, 66The Jefferson Lab Hall A Collaboration, 67The Jefferson Lab Hall A Collaboration, 68The Jefferson Lab Hall A Collaboration, 69The Jefferson Lab Hall A Collaboration, 70The Jefferson Lab Hall A Collaboration, 71The Jefferson Lab Hall A Collaboration, 72The Jefferson Lab Hall A Collaboration, 73The Jefferson Lab Hall A Collaboration, 74The Jefferson Lab Hall A Collaboration, 75The Jefferson Lab Hall A Collaboration, 76The Jefferson Lab Hall A Collaboration, 77The Jefferson Lab Hall A Collaboration, 78The Jefferson Lab Hall A Collaboration, 79The Jefferson Lab Hall A Collaboration, 80The Jefferson Lab Hall A Collaboration, 81The Jefferson Lab Hall A Collaboration, 82The Jefferson Lab Hall A Collaboration, 83The Jefferson Lab Hall A Collaboration, 84The Jefferson Lab Hall A Collaboration, 85The Jefferson Lab Hall A Collaboration, 86The Jefferson Lab Hall A Collaboration, 87The Jefferson Lab Hall A Collaboration, 88The Jefferson Lab Hall A Collaboration, 89The Jefferson Lab Hall A Collaboration, 90The Jefferson Lab Hall A Collaboration, 91The Jefferson Lab Hall A Collaboration, 92The Jefferson Lab Hall A Collaboration

We have performed precision measurements of the double-spin virtual-photon asymmetry $A_1$ on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer. Our data cover a wide kinematic range $0.277 \leq x \leq 0. Read More

2014Apr
Authors: Y. X. Zhao1, Y. Wang2, K. Allada3, K. Aniol4, J. R. M. Annand5, T. Averett6, F. Benmokhtar7, W. Bertozzi8, P. C. Bradshaw9, P. Bosted10, A. Camsonne11, M. Canan12, G. D. Cates13, C. Chen14, J. -P. Chen15, W. Chen16, K. Chirapatpimol17, E. Chudakov18, E. Cisbani19, J. C. Cornejo20, F. Cusanno21, M. M. Dalton22, W. Deconinck23, C. W. de Jager24, R. De Leo25, X. Deng26, A. Deur27, H. Ding28, P. A. M. Dolph29, C. Dutta30, D. Dutta31, L. El Fassi32, S. Frullani33, H. Gao34, F. Garibaldi35, D. Gaskell36, S. Gilad37, R. Gilman38, O. Glamazdin39, S. Golge40, L. Guo41, D. Hamilton42, O. Hansen43, D. W. Higinbotham44, T. Holmstrom45, J. Huang46, M. Huang47, H. F Ibrahim48, M. Iodice49, X. Jiang50, G. Jin51, M. K. Jones52, J. Katich53, A. Kelleher54, W. Kim55, A. Kolarkar56, W. Korsch57, J. J. LeRose58, X. Li59, Y. Li60, R. Lindgren61, N. Liyanage62, E. Long63, H. -J. Lu64, D. J. Margaziotis65, P. Markowitz66, S. Marrone67, D. McNulty68, Z. -E. Meziani69, R. Michaels70, B. Moffit71, C. Muñoz Camacho72, S. Nanda73, A. Narayan74, V. Nelyubin75, B. Norum76, Y. Oh77, M. Osipenko78, D. Parno79, J. -C. Peng80, S. K. Phillips81, M. Posik82, A. J. R. Puckett83, X. Qian84, Y. Qiang85, A. Rakhman86, R. Ransome87, S. Riordan88, A. Saha89, B. Sawatzky90, E. Schulte91, A. Shahinyan92, M. H. Shabestari93, S. Širca94, S. Stepanyan95, R. Subedi96, V. Sulkosky97, L. -G. Tang98, A. Tobias99, G. M. Urciuoli100, I. Vilardi101, K. Wang102, B. Wojtsekhowski103, X. Yan104, H. Yao105, Y. Ye106, Z. Ye107, L. Yuan108, X. Zhan109, Y. Zhang110, Y. -W. Zhang111, B. Zhao112, X. Zheng113, L. Zhu114, X. Zhu115, X. Zong116
Affiliations: 1Jefferson Lab Hall A Collaboration, 2Jefferson Lab Hall A Collaboration, 3Jefferson Lab Hall A Collaboration, 4Jefferson Lab Hall A Collaboration, 5Jefferson Lab Hall A Collaboration, 6Jefferson Lab Hall A Collaboration, 7Jefferson Lab Hall A Collaboration, 8Jefferson Lab Hall A Collaboration, 9Jefferson Lab Hall A Collaboration, 10Jefferson Lab Hall A Collaboration, 11Jefferson Lab Hall A Collaboration, 12Jefferson Lab Hall A Collaboration, 13Jefferson Lab Hall A Collaboration, 14Jefferson Lab Hall A Collaboration, 15Jefferson Lab Hall A Collaboration, 16Jefferson Lab Hall A Collaboration, 17Jefferson Lab Hall A Collaboration, 18Jefferson Lab Hall A Collaboration, 19Jefferson Lab Hall A Collaboration, 20Jefferson Lab Hall A Collaboration, 21Jefferson Lab Hall A Collaboration, 22Jefferson Lab Hall A Collaboration, 23Jefferson Lab Hall A Collaboration, 24Jefferson Lab Hall A Collaboration, 25Jefferson Lab Hall A Collaboration, 26Jefferson Lab Hall A Collaboration, 27Jefferson Lab Hall A Collaboration, 28Jefferson Lab Hall A Collaboration, 29Jefferson Lab Hall A Collaboration, 30Jefferson Lab Hall A Collaboration, 31Jefferson Lab Hall A Collaboration, 32Jefferson Lab Hall A Collaboration, 33Jefferson Lab Hall A Collaboration, 34Jefferson Lab Hall A Collaboration, 35Jefferson Lab Hall A Collaboration, 36Jefferson Lab Hall A Collaboration, 37Jefferson Lab Hall A Collaboration, 38Jefferson Lab Hall A Collaboration, 39Jefferson Lab Hall A Collaboration, 40Jefferson Lab Hall A Collaboration, 41Jefferson Lab Hall A Collaboration, 42Jefferson Lab Hall A Collaboration, 43Jefferson Lab Hall A Collaboration, 44Jefferson Lab Hall A Collaboration, 45Jefferson Lab Hall A Collaboration, 46Jefferson Lab Hall A Collaboration, 47Jefferson Lab Hall A Collaboration, 48Jefferson Lab Hall A Collaboration, 49Jefferson Lab Hall A Collaboration, 50Jefferson Lab Hall A Collaboration, 51Jefferson Lab Hall A Collaboration, 52Jefferson Lab Hall A Collaboration, 53Jefferson Lab Hall A Collaboration, 54Jefferson Lab Hall A Collaboration, 55Jefferson Lab Hall A Collaboration, 56Jefferson Lab Hall A Collaboration, 57Jefferson Lab Hall A Collaboration, 58Jefferson Lab Hall A Collaboration, 59Jefferson Lab Hall A Collaboration, 60Jefferson Lab Hall A Collaboration, 61Jefferson Lab Hall A Collaboration, 62Jefferson Lab Hall A Collaboration, 63Jefferson Lab Hall A Collaboration, 64Jefferson Lab Hall A Collaboration, 65Jefferson Lab Hall A Collaboration, 66Jefferson Lab Hall A Collaboration, 67Jefferson Lab Hall A Collaboration, 68Jefferson Lab Hall A Collaboration, 69Jefferson Lab Hall A Collaboration, 70Jefferson Lab Hall A Collaboration, 71Jefferson Lab Hall A Collaboration, 72Jefferson Lab Hall A Collaboration, 73Jefferson Lab Hall A Collaboration, 74Jefferson Lab Hall A Collaboration, 75Jefferson Lab Hall A Collaboration, 76Jefferson Lab Hall A Collaboration, 77Jefferson Lab Hall A Collaboration, 78Jefferson Lab Hall A Collaboration, 79Jefferson Lab Hall A Collaboration, 80Jefferson Lab Hall A Collaboration, 81Jefferson Lab Hall A Collaboration, 82Jefferson Lab Hall A Collaboration, 83Jefferson Lab Hall A Collaboration, 84Jefferson Lab Hall A Collaboration, 85Jefferson Lab Hall A Collaboration, 86Jefferson Lab Hall A Collaboration, 87Jefferson Lab Hall A Collaboration, 88Jefferson Lab Hall A Collaboration, 89Jefferson Lab Hall A Collaboration, 90Jefferson Lab Hall A Collaboration, 91Jefferson Lab Hall A Collaboration, 92Jefferson Lab Hall A Collaboration, 93Jefferson Lab Hall A Collaboration, 94Jefferson Lab Hall A Collaboration, 95Jefferson Lab Hall A Collaboration, 96Jefferson Lab Hall A Collaboration, 97Jefferson Lab Hall A Collaboration, 98Jefferson Lab Hall A Collaboration, 99Jefferson Lab Hall A Collaboration, 100Jefferson Lab Hall A Collaboration, 101Jefferson Lab Hall A Collaboration, 102Jefferson Lab Hall A Collaboration, 103Jefferson Lab Hall A Collaboration, 104Jefferson Lab Hall A Collaboration, 105Jefferson Lab Hall A Collaboration, 106Jefferson Lab Hall A Collaboration, 107Jefferson Lab Hall A Collaboration, 108Jefferson Lab Hall A Collaboration, 109Jefferson Lab Hall A Collaboration, 110Jefferson Lab Hall A Collaboration, 111Jefferson Lab Hall A Collaboration, 112Jefferson Lab Hall A Collaboration, 113Jefferson Lab Hall A Collaboration, 114Jefferson Lab Hall A Collaboration, 115Jefferson Lab Hall A Collaboration, 116Jefferson Lab Hall A Collaboration

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized $^3{\rm{He}}$ target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1$<$$x_{bj}$$<$0. Read More

2014Jan

We studied simultaneously the 4He(e,e'p), 4He(e,e'pp), and 4He(e,e'pn) reactions at Q^2=2 [GeV/c]2 and x_B>1, for a (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum in a region where the nucleon-nucleon force is expected to change from predominantly tensor to repulsive. Read More

2013Dec

An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized $^3$He target was performed at Jefferson Lab in the kinematic region of $0.16Read More

2013Nov
Authors: K. Allada1, Y. X. Zhao2, K. Aniol3, J. R. M. Annand4, T. Averett5, F. Benmokhtar6, W. Bertozzi7, P. C. Bradshaw8, P. Bosted9, A. Camsonne10, M. Canan11, G. D. Cates12, C. Chen13, J. -P. Chen14, W. Chen15, K. Chirapatpimol16, E. Chudakov17, E. Cisbani18, J. C. Cornejo19, F. Cusanno20, M. Dalton21, W. Deconinck22, C. W. de Jager23, R. De Leo24, X. Deng25, A. Deur26, H. Ding27, P. A. M. Dolph28, C. Dutta29, D. Dutta30, L. El Fassi31, S. Frullani32, H. Gao33, F. Garibaldi34, D. Gaskell35, S. Gilad36, R. Gilman37, O. Glamazdin38, S. Golge39, L. Guo40, D. Hamilton41, O. Hansen42, D. W. Higinbotham43, T. Holmstrom44, J. Huang45, M. Huang46, H. F Ibrahim47, M. Iodice48, X. Jiang49, G. Jin50, M. K. Jones51, J. Katich52, A. Kelleher53, W. Kim54, A. Kolarkar55, W. Korsch56, J. J. LeRose57, X. Li58, Y. Li59, R. Lindgren60, N. Liyanage61, E. Long62, H. -J. Lu63, D. J. Margaziotis64, P. Markowitz65, S. Marrone66, D. McNulty67, Z. -E. Meziani68, R. Michaels69, B. Moffit70, C. Munoz Camacho71, S. Nanda72, A. Narayan73, V. Nelyubin74, B. Norum75, Y. Oh76, M. Osipenko77, D. Parno78, J. -C. Peng79, S. K. Phillips80, M. Posik81, A. J. R. Puckett82, X. Qian83, Y. Qiang84, A. Rakhman85, R. Ransome86, S. Riordan87, A. Saha88, B. Sawatzky89, E. Schulte90, A. Shahinyan91, M. H. Shabestari92, S. Sirca93, S. Stepanyan94, R. Subedi95, V. Sulkosky96, L. -G. Tang97, A. Tobias98, G. M. Urciuoli99, I. Vilardi100, K. Wang101, Y. Wang102, B. Wojtsekhowski103, X. Yan104, H. Yao105, Y. Ye106, Z. Ye107, L. Yuan108, X. Zhan109, Y. Zhang110, Y. -W. Zhang111, B. Zhao112, X. Zheng113, L. Zhu114, X. Zhu115, X. Zong116
Affiliations: 1Jefferson Lab Hall A Collaboration, 2Jefferson Lab Hall A Collaboration, 3Jefferson Lab Hall A Collaboration, 4Jefferson Lab Hall A Collaboration, 5Jefferson Lab Hall A Collaboration, 6Jefferson Lab Hall A Collaboration, 7Jefferson Lab Hall A Collaboration, 8Jefferson Lab Hall A Collaboration, 9Jefferson Lab Hall A Collaboration, 10Jefferson Lab Hall A Collaboration, 11Jefferson Lab Hall A Collaboration, 12Jefferson Lab Hall A Collaboration, 13Jefferson Lab Hall A Collaboration, 14Jefferson Lab Hall A Collaboration, 15Jefferson Lab Hall A Collaboration, 16Jefferson Lab Hall A Collaboration, 17Jefferson Lab Hall A Collaboration, 18Jefferson Lab Hall A Collaboration, 19Jefferson Lab Hall A Collaboration, 20Jefferson Lab Hall A Collaboration, 21Jefferson Lab Hall A Collaboration, 22Jefferson Lab Hall A Collaboration, 23Jefferson Lab Hall A Collaboration, 24Jefferson Lab Hall A Collaboration, 25Jefferson Lab Hall A Collaboration, 26Jefferson Lab Hall A Collaboration, 27Jefferson Lab Hall A Collaboration, 28Jefferson Lab Hall A Collaboration, 29Jefferson Lab Hall A Collaboration, 30Jefferson Lab Hall A Collaboration, 31Jefferson Lab Hall A Collaboration, 32Jefferson Lab Hall A Collaboration, 33Jefferson Lab Hall A Collaboration, 34Jefferson Lab Hall A Collaboration, 35Jefferson Lab Hall A Collaboration, 36Jefferson Lab Hall A Collaboration, 37Jefferson Lab Hall A Collaboration, 38Jefferson Lab Hall A Collaboration, 39Jefferson Lab Hall A Collaboration, 40Jefferson Lab Hall A Collaboration, 41Jefferson Lab Hall A Collaboration, 42Jefferson Lab Hall A Collaboration, 43Jefferson Lab Hall A Collaboration, 44Jefferson Lab Hall A Collaboration, 45Jefferson Lab Hall A Collaboration, 46Jefferson Lab Hall A Collaboration, 47Jefferson Lab Hall A Collaboration, 48Jefferson Lab Hall A Collaboration, 49Jefferson Lab Hall A Collaboration, 50Jefferson Lab Hall A Collaboration, 51Jefferson Lab Hall A Collaboration, 52Jefferson Lab Hall A Collaboration, 53Jefferson Lab Hall A Collaboration, 54Jefferson Lab Hall A Collaboration, 55Jefferson Lab Hall A Collaboration, 56Jefferson Lab Hall A Collaboration, 57Jefferson Lab Hall A Collaboration, 58Jefferson Lab Hall A Collaboration, 59Jefferson Lab Hall A Collaboration, 60Jefferson Lab Hall A Collaboration, 61Jefferson Lab Hall A Collaboration, 62Jefferson Lab Hall A Collaboration, 63Jefferson Lab Hall A Collaboration, 64Jefferson Lab Hall A Collaboration, 65Jefferson Lab Hall A Collaboration, 66Jefferson Lab Hall A Collaboration, 67Jefferson Lab Hall A Collaboration, 68Jefferson Lab Hall A Collaboration, 69Jefferson Lab Hall A Collaboration, 70Jefferson Lab Hall A Collaboration, 71Jefferson Lab Hall A Collaboration, 72Jefferson Lab Hall A Collaboration, 73Jefferson Lab Hall A Collaboration, 74Jefferson Lab Hall A Collaboration, 75Jefferson Lab Hall A Collaboration, 76Jefferson Lab Hall A Collaboration, 77Jefferson Lab Hall A Collaboration, 78Jefferson Lab Hall A Collaboration, 79Jefferson Lab Hall A Collaboration, 80Jefferson Lab Hall A Collaboration, 81Jefferson Lab Hall A Collaboration, 82Jefferson Lab Hall A Collaboration, 83Jefferson Lab Hall A Collaboration, 84Jefferson Lab Hall A Collaboration, 85Jefferson Lab Hall A Collaboration, 86Jefferson Lab Hall A Collaboration, 87Jefferson Lab Hall A Collaboration, 88Jefferson Lab Hall A Collaboration, 89Jefferson Lab Hall A Collaboration, 90Jefferson Lab Hall A Collaboration, 91Jefferson Lab Hall A Collaboration, 92Jefferson Lab Hall A Collaboration, 93Jefferson Lab Hall A Collaboration, 94Jefferson Lab Hall A Collaboration, 95Jefferson Lab Hall A Collaboration, 96Jefferson Lab Hall A Collaboration, 97Jefferson Lab Hall A Collaboration, 98Jefferson Lab Hall A Collaboration, 99Jefferson Lab Hall A Collaboration, 100Jefferson Lab Hall A Collaboration, 101Jefferson Lab Hall A Collaboration, 102Jefferson Lab Hall A Collaboration, 103Jefferson Lab Hall A Collaboration, 104Jefferson Lab Hall A Collaboration, 105Jefferson Lab Hall A Collaboration, 106Jefferson Lab Hall A Collaboration, 107Jefferson Lab Hall A Collaboration, 108Jefferson Lab Hall A Collaboration, 109Jefferson Lab Hall A Collaboration, 110Jefferson Lab Hall A Collaboration, 111Jefferson Lab Hall A Collaboration, 112Jefferson Lab Hall A Collaboration, 113Jefferson Lab Hall A Collaboration, 114Jefferson Lab Hall A Collaboration, 115Jefferson Lab Hall A Collaboration, 116Jefferson Lab Hall A Collaboration

We report the first measurement of target single-spin asymmetries (A$_N$) in the inclusive hadron production reaction, $e~$+$~^3\text{He}^{\uparrow}\rightarrow h+X$, using a transversely polarized $^3$He target. The experiment was conducted at Jefferson Lab in Hall A using a 5.9-GeV electron beam. Read More

2013Nov

We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction $^3$He$^{\uparrow}\left(e,e' \right)X$ on a polarized $^3$He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be non-zero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5. Read More

The charge form factor of $^$4He has been extracted in the range 29 fm$^{-2}$ $\le Q^2 \le 77$ fm$^{-2}$ from elastic electron scattering, detecting $^4$He nuclei and electrons in coincidence with the High Resolution Spectrometers of the Hall A Facility of Jefferson Lab. The results are in qualitative agreement with realistic meson-nucleon theoretical calculations. The data have uncovered a second diffraction minimum, which was predicted in the $Q^2$ range of this experiment, and rule out conclusively long-standing predictions of dimensional scaling of high-energy amplitudes using quark counting. Read More

We present the development of high-performance polarized $^3\mathrm{He}$ targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized $^3\mathrm{He}$ targets, as well as the target properties and operating parameters that made those improvements possible. Read More

Metric $f(R)$ gravity theories behave like GR with cosmological constant when $f"(R)$ = 0, and like scalar-tensor theories elsewhere. I investigate the transition from $f"(R) \neq 0$ to $f"(R) = 0$, and show that this theory may offer a way to explain Dark Energy and/or Dark Matter without having to make use of the chameleon mechanism to agree with solar system tests. Read More

2013Jul
Affiliations: 1Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 2Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 3Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 4Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 5Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 6Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 7Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 8Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 9Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 10Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 11Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 12Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 13Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 14Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 15Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 16Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 17Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 18Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 19Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 20Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 21Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 22Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 23Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA, USA and the Bates Research and Engineering Center, Middleton MA, 24Jefferson Lab, Newport News, VA USA, 25Jefferson Lab, Newport News, VA USA, 26Jefferson Lab, Newport News, VA USA, 27Jefferson Lab, Newport News, VA USA, 28Jefferson Lab, Newport News, VA USA, 29Jefferson Lab, Newport News, VA USA, 30Jefferson Lab, Newport News, VA USA, 31Jefferson Lab, Newport News, VA USA, 32Jefferson Lab, Newport News, VA USA, 33Jefferson Lab, Newport News, VA USA, 34Jefferson Lab, Newport News, VA USA, 35Jefferson Lab, Newport News, VA USA, 36Jefferson Lab, Newport News, VA USA, 37Jefferson Lab, Newport News, VA USA, 38Jefferson Lab, Newport News, VA USA, 39Jefferson Lab, Newport News, VA USA, 40Jefferson Lab, Newport News, VA USA, 41Jefferson Lab, Newport News, VA USA, 42Jefferson Lab, Newport News, VA USA, 43Jefferson Lab, Newport News, VA USA, 44Jefferson Lab, Newport News, VA USA, 45Jefferson Lab, Newport News, VA USA, 46Physics Dept. U.C. Berkeley, Berkeley, CA USA, 47Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD USA, 48Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD USA, 49Physics Department, Arizona State University, Tempe, 50Physics Department, Arizona State University, Tempe, 51Los Alamos National Laboratory, Los Alamos NM USA, 52Physics Dept., Hampton University, Hampton, VA and Jefferson Lab, Newport News, VA USA, 53Physics Dept., Hampton University, Hampton, VA and Jefferson Lab, Newport News, VA USA, 54Physics Dept., Hampton University, Hampton, VA and Jefferson Lab, Newport News, VA USA, 55Physics Dept., Catholic University of America, Washington, DC USA, 56Physics Dept., Catholic University of America, Washington, DC USA, 57Physics Dept., Catholic University of America, Washington, DC USA, 58Temple University, Philadelphia PA USA, 59Temple University, Philadelphia PA USA, 60Temple University, Philadelphia PA USA, 61Temple University, Philadelphia PA USA, 62Temple University, Philadelphia PA USA, 63University Bonn, Bonn Germany, 64University Bonn, Bonn Germany, 65University Bonn, Bonn Germany, 66Physikalisches Institut Justus-Liebig-Universitt Giessen, Giessen Germany, 67Physikalisches Institut Justus-Liebig-Universitt Giessen, Giessen Germany

We give a short overview of the DarkLight detector concept which is designed to search for a heavy photon A' with a mass in the range 10 MeV/c^2 < m(A') < 90 MeV/c^2 and which decays to lepton pairs. We describe the intended operating environment, the Jefferson Laboratory free electon laser, and a way to extend DarkLight's reach using A' --> invisible decays. Read More

2013May
Affiliations: 1Laboratory for Nuclear Science, Massachusetts Institute of Technology, 2Department of Physics, Arizona State University, 3Department of Physics, Arizona State University, 4Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 5Laboratory for Nuclear Science, Massachusetts Institute of Technology, 6Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 7Laboratory for Nuclear Science, Massachusetts Institute of Technology, 8Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 9Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 10Laboratory for Nuclear Science, Massachusetts Institute of Technology, 11Laboratory for Nuclear Science, Massachusetts Institute of Technology, 12Department of Physics, Hampton University, 13Laboratory for Nuclear Science, Massachusetts Institute of Technology, 14Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 15Laboratory for Nuclear Science, Massachusetts Institute of Technology, 16Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 17Laboratory for Nuclear Science, Massachusetts Institute of Technology, 18Laboratory for Nuclear Science, Massachusetts Institute of Technology, 19Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 20Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA, 21Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA

Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Read More

2013May
Affiliations: 1Department of Physics, Arizona State University, USA, 2Department of Physics, Arizona State University, USA, 3Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 4Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 5Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 6Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 7Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 8Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 9Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 10Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 11Department of Physics, Hampton University, VA USA, 12Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 13Department of Physics, College of William and Mary, Williamsburg, USA, 14Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 15Department of Physics, University of New Hampshire, USA, 16Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 17Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 18Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 19Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 20Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 21Laboratory for Nuclear Science, Massachussetts Institute of Technology, USA, 22Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA, 23Free Electron Laser Group, Thomas Jefferson National Accelerator Facility, VA USA

We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. Read More

High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration for this new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jefferson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Read More

The five-fold differential cross section for the 12C(e,e'p)11B reaction was determined over a missing momentum range of 200-400 MeV/c, in a kinematics regime with Bjorken x > 1 and Q2 = 2.0 (GeV/c)2. A comparison of the results and theoretical models and previous lower missing momentum data is shown. Read More

2012Aug
Authors: The HAPPEX, PREX Collaborations, :, S. Abrahamyan, A. Acha, A. Afanasev, Z. Ahmed, H. Albataineh, K. Aniol, D. S. Armstrong, W. Armstrong, J. Arrington, T. Averett, B. Babineau, S. L. Bailey, J. Barber, A. Barbieri, A. Beck, V. Bellini, R. Beminiwattha, H. Benaoum, J. Benesch, F. Benmokhtar, P. Bertin, T. Bielarski, W. Boeglin, P. Bosted, F. Butaru, E. Burtin, J. Cahoon, A. Camsonne, M. Canan, P. Carter, C. C. Chang, G. D. Cates, Y. C. Chao, C. Chen, J. P. Chen, Seonho Choi, E. Chudakov, E. Cisbani, B. Craver, F. Cusanno, M. M. Dalton, R. De Leo, K. de Jager, W. Deconinck, P. Decowski, D. Deepa, X. Deng, A. Deur, D. Dutta, A. Etile, C. Ferdi, R. J. Feuerbach, J. M. Finn, D. Flay, G. B. Franklin, M. Friend, S. Frullani, E. Fuchey, S. A. Fuchs, K. Fuoti, F. Garibaldi, E. Gasser, R. Gilman, A. Giusa, A. Glamazdin, L. E. Glesener, J. Gomez, M. Gorchtein, J. Grames, K. Grimm, C. Gu, O. Hansen, J. Hansknecht, O. Hen, D. W. Higinbotham, R. S. Holmes, T. Holmstrom, C. J. Horowitz, J. Hoskins, J. Huang, T. B. Humensky, C. E. Hyde, H. Ibrahim, F. Itard, C. M. Jen, E. Jensen, X. Jiang, G. Jin, S. Johnston, J. Katich, L. J. Kaufman, A. Kelleher, K. Kliakhandler, P. M. King, A. Kolarkar, S. Kowalski, E. Kuchina, K. S. Kumar, L. Lagamba, D. Lambert, P. LaViolette, J. Leacock, J. Leckey IV, J. H. Lee, J. J. LeRose, D. Lhuillier, R. Lindgren, N. Liyanage, N. Lubinsky, J. Mammei, F. Mammoliti, D. J. Margaziotis, P. Markowitz, M. Mazouz, K. McCormick, A. McCreary, D. McNulty, D. G. Meekins, L. Mercado, Z. E. Meziani, R. W. Michaels, M. Mihovilovic, B. Moffit, P. Monaghan, N. Muangma, C. Munoz-Camacho, S. Nanda, V. Nelyubin, D. Neyret, Nuruzzaman, Y. Oh, K. Otis, A. Palmer, D. Parno, K. D. Paschke, S. K. Phillips, M. Poelker, R. Pomatsalyuk, M. Posik, M. Potokar, K. Prok, A. J. R. Puckett, X. Qian, Y. Qiang, B. Quinn, A. Rakhman, P. E. Reimer, B. Reitz, S. Riordan, J. Roche, P. Rogan, G. Ron, G. Russo, K. Saenboonruang, A. Saha, B. Sawatzky, A. Shahinyan, R. Silwal, J. Singh, S. Sirca, K. Slifer, R. Snyder, P. Solvignon, P. A. Souder, M. L. Sperduto, R. Subedi, M. L. Stutzman, R. Suleiman, V. Sulkosky, C. M. Sutera, W. A. Tobias, W. Troth, G. M. Urciuoli, P. Ulmer, A. Vacheret, E. Voutier, B. Waidyawansa, D. Wang, K. Wang, J. Wexler, A. Whitbeck, R. Wilson, B. Wojtsekhowski, X. Yan, H. Yao, Y. Ye, Z. Ye, V. Yim, L. Zana, X. Zhan, J. Zhang, Y. Zhang, X. Zheng, V. Ziskin, P. Zhu

We have measured the beam-normal single-spin asymmetry $A_n$ in the elastic scattering of 1-3 GeV transversely polarized electrons from $^1$H and for the first time from $^4$He, $^{12}$C, and $^{208}$Pb. For $^1$H, $^4$He and $^{12}$C, the measurements are in agreement with calculations that relate $A_n$ to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the $^{208}$Pb result is significantly smaller than the corresponding prediction using the same formalism. Read More

2012Jan
Authors: S. Abrahamyan, Z. Ahmed, H. Albataineh, K. Aniol, D. S. Armstrong, W. Armstrong, T. Averett, B. Babineau, A. Barbieri, V. Bellini, R. Beminiwattha, J. Benesch, F. Benmokhtar, T. Bielarski, W. Boeglin, A. Camsonne, M. Canan, P. Carter, G. D. Cates, C. Chen, J. -P. Chen, O. Hen, F. Cusanno, M. M. Dalton, R. De Leo, K. de Jager, W. Deconinck, P. Decowski, X. Deng, A. Deur, D. Dutta, A. Etile, D. Flay, G. B. Franklin, M. Friend, S. Frullani, E. Fuchey, F. Garibaldi, E. Gasser, R. Gilman, A. Giusa, A. Glamazdin, J. Gomez, J. Grames, C. Gu, O. Hansen, J. Hansknecht, D. W. Higinbotham, R. S. Holmes, T. Holmstrom, C. J. Horowitz, J. Hoskins, J. Huang, C. E. Hyde, F. Itard, C. -M. Jen, E. Jensen, G. Jin, S. Johnston, A. Kelleher, K. Kliakhandler, P. M. King, S. Kowalski, K. S. Kumar, J. Leacock, J. Leckey IV, J. H. Lee, J. J. LeRose, R. Lindgren, N. Liyanage, N. Lubinsky, J. Mammei, F. Mammoliti, D. J. Margaziotis, P. Markowitz, A. McCreary, D. McNulty, L. Mercado, Z. -E. Meziani, R. W. Michaels, M. Mihovilovic, N. Muangma, C. Muñoz-Camacho, S. Nanda, V. Nelyubin, N. Nuruzzaman, Y. Oh, A. Palmer, D. Parno, K. D. Paschke, S. K. Phillips, B. Poelker, R. Pomatsalyuk, M. Posik, A. J. R. Puckett, B. Quinn, A. Rakhman, P. E. Reimer, S. Riordan, P. Rogan, G. Ron, G. Russo, K. Saenboonruang, A. Saha, B. Sawatzky, A. Shahinyan, R. Silwal, S. Sirca, K. Slifer, P. Solvignon, P. A. Souder, M. L. Sperduto, R. Subedi, R. Suleiman, V. Sulkosky, C. M. Sutera, W. A. Tobias, W. Troth, G. M. Urciuoli, B. Waidyawansa, D. Wang, J. Wexler, R. Wilson, B. Wojtsekhowski, X. Yan, H. Yao, Y. Ye, Z. Ye, V. Yim, L. Zana, X. Zhan, J. Zhang, Y. Zhang, X. Zheng, P. Zhu

We report the first measurement of the parity-violating asymmetry A_PV in the elastic scattering of polarized electrons from 208Pb. A_PV is sensitive to the radius of the neutron distribution (Rn). The result A_PV = 0. Read More

We present a search at Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling $\alpha'$ to electrons. Such a particle $A'$ can be produced in electron-nucleus fixed-target scattering and then decay to an $e^+e^-$ pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175--250 MeV, found no evidence for an $A'\to e^+e^-$ reaction, and set an upper limit of $\alpha'/\alpha \simeq 10^{-6}$. Read More

2011Aug

We report the first measurement of the double-spin asymmetry $A_{LT}$ for charged pion electroproduction in semi\nobreakdash-inclusive deep\nobreakdash-inelastic electron scattering on a transversely polarized $^{3}$He target. The kinematics focused on the valence quark region, $0.16Read More

2011Jul
Affiliations: 1University of Virginia, Charlottesville, VA, 2University of Virginia, Charlottesville, VA, 3College of William and Mary, Williamsburg, VA, 4College of William and Mary, Williamsburg, VA, 5University of Virginia, Charlottesville, VA, 6University of Virginia, Charlottesville, VA, 7University of Virginia, Charlottesville, VA, 8Thomas Jefferson National Accelerator Facility, Newport News, VA, 9University of Virginia, Charlottesville, VA

The dynamics of the movement of gas is discussed for two-chambered polarized He-3 target cells of the sort that have been used successfully for many electron scattering experiments. A detailed analysis is presented showing that diffusion is a limiting factor in target performance, particularly as these targets are run at increasingly high luminosities. Measurements are presented on a new prototype polarized He-3 target cell in which the movement of gas is due largely to convection instead of diffusion. Read More

2011Jun

We report the first measurement of target single spin asymmetries in the semi-inclusive $^3{He}(e,e'\pi^\pm)X$ reaction on a transversely polarized target. The experiment, conducted at Jefferson Lab using a 5.9 GeV electron beam, covers a range of 0. Read More

We present an updated extraction of the proton electromagnetic form factor ratio, mu_p G_E/G_M, at low Q^2. The form factors are sensitive to the spatial distribution of the proton, and precise measurements can be used to constrain models of the proton. An improved selection of the elastic events and reduced background contributions yielded a small systematic reduction in the ratio mu_p G_E/G_M compared to the original analysis. Read More

2010Aug
Authors: S. Riordan, S. Abrahamyan, B. Craver, A. Kelleher, A. Kolarkar, J. Miller, G. D. Cates, N. Liyanage, B. Wojtsekhowski, A. Acha, K. Allada, B. Anderson, K. A. Aniol, J. R. M. Annand, J. Arrington, T. Averett, A. Beck, M. Bellis, W. Boeglin, H. Breuer, J. R. Calarco, A. Camsonne, J. P. Chen, E. Chudakov, L. Coman, B. Crowe, F. Cusanno, D. Day, P. Degtyarenko, P. A. M. Dolph, C. Dutta, C. Ferdi, C. Fernandez-Ramirez, R. Feuerbach, L. M. Fraile, G. Franklin, S. Frullani, S. Fuchs, F. Garibaldi, N. Gevorgyan, R. Gilman, A. Glamazdin, J. Gomez, K. Grimm, J. O. Hansen, J. L. Herraiz, D. W. Higinbotham, R. Holmes, T. Holmstrom, D. Howell, C. W. deJager, X. Jiang, M. K. Jones, J. Katich, L. J. Kaufman, M. Khandaker, J. J. Kelly, D. Kiselev, W. Korsch, J. LeRose, R. Lindgren, P. Markowitz, D. J. Margaziotis, S. May-Tal Beck, S. Mayilyan, K. McCormick, Z. E. Meziani, R. Michaels, B. Moffit, S. Nanda, V. Nelyubin, T. Ngo, D. M. Nikolenko, B. Norum, L. Pentchev, C. F. Perdrisat, E. Piasetzky, R. Pomatsalyuk, D. Protopopescu, A. J. R. Puckett, V. A. Punjabi, X. Qian, Y. Qiang, B. Quinn, I. Rachek, R. D. Ransome, P. E. Reimer, B. Reitz, J. Roche, G. Ron, O. Rondon, G. Rosner, A. Saha, M. Sargsian, B. Sawatzky, J. Segal, M. Shabestari, A. Shahinyan, Yu. Shestakov, J. Singh, S. Sirca, P. Souder, S. Stepanyan, V. Stibunov, V. Sulkosky, S. Tajima, W. A. Tobias, J. M. Udias, G. M. Urciuoli, B. Vlahovic, H. Voskanyan, K. Wang, F. R. Wesselmann, J. R. Vignote, S. A. Wood, J. Wright, H. Yao, X. Zhu

The electric form factor of the neutron was determined from studies of the reaction He3(e,e'n)pp in quasi-elastic kinematics in Hall A at Jefferson Lab. Longitudinally polarized electrons were scattered off a polarized target in which the nuclear polarization was oriented perpendicular to the momentum transfer. The scattered electrons were detected in a magnetic spectrometer in coincidence with neutrons that were registered in a large-solid-angle detector. Read More

High precision measurements of induced and transferred recoil proton polarization in d(polarized gamma, polarized p})n have been performed for photon energies of 277--357 MeV and theta_cm = 20 degrees -- 120 degrees. The measurements were motivated by a longstanding discrepancy between meson-baryon model calculations and data at higher energies. At the low energies of this experiment, theory continues to fail to reproduce the data, indicating that either something is missing in the calculations and/or there is a problem with the accuracy of the nucleon-nucleon potential being used. Read More

The protons and neutrons in a nucleus can form strongly correlated nucleon pairs. Scattering experiments, where a proton is knocked-out of the nucleus with high momentum transfer and high missing momentum, show that in 12C the neutron-proton pairs are nearly twenty times as prevalent as proton-proton pairs and, by inference, neutron-neutron pairs. This difference between the types of pairs is due to the nature of the strong force and has implications for understanding cold dense nuclear systems such as neutron stars. Read More

The accelerated expansion of the universe is ascribed to the existence of dark energy. Black holes accretion of dark energy induces a mass change proportional to the energy density and pressure of the background dark energy fluid. The time scale during which the mass of black holes changes considerably is too long relative to the age of the universe, thus beyond detection possibilities. Read More

The equation of state (EoS) of dark energy $w$ remains elusive despite enormous experimental efforts to pin down its value and its time variation. Yet it is the single most important handle we have in our understanding of one of the most mysterious puzzle in nature, dark energy. This letter proposes a new method for measuring the EoS of dark energy by using the gravitational waves (GW) of black hole binaries. Read More