290 results on '"Okayasu, Y."'
Search Results
2. Spectroscopy of $A=9$ hyperlithium by the $(e,e^{\prime}K^{+})$ reaction
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Gogami, T., Chen, C., Kawama, D., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Baturin, P., Badui, R., Boeglin, W., Bono, J., Brash, E., Carter, P., Chiba, A., Christy, E., Danagoulian, S., De Leo, R., Doi, D., Elaasar, M., Ent, R., Fujii, Y., Fujita, M., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Han, Y., Hashimoto, O., Horn, T., Hu, B., Hungerford, Ed. V., Jones, M., Kanda, H., Kaneta, M., Kato, S., Kawai, M., Khanal, H., Kohl, M., Liyanage, A., Luo, W., Maeda, K., Margaryan, A., Markowitz, P., Maruta, T., Matsumura, A., Maxwell, V., Meekins, D., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Nakamura, S. N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M. I., Nunez, A., Nuruzzaman, Okayasu, Y., Petkovic, T., Pochodzalla, J., Qiu, X., Reinhold, J., Rodriguez, V. M., Samanta, C., Sawatzky, B., Seva, T., Shichijo, A., Tadevosyan, V., Tang, L., Taniya, N., Tsukada, K., Veilleux, M., Vulcan, W., Wesselmann, F. R., Wood, S. A., Yamamoto, T., Ya, L., Ye, Z., Yokota, K., Yuan, L., Zhamkochyan, S., and Zhu, L.
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Nuclear Experiment - Abstract
Missing mass spectroscopy with the $(e,e^{\prime}K^{+})$ reaction was performed at Jefferson Laboratory's Hall C for the neutron rich $\Lambda$ hypernucleus $^{9}_{\Lambda}{\rm Li}$. The ground state energy was obtained to be $B_{\Lambda}^{\rm g.s.}=8.84\pm0.17^{\rm stat.}\pm0.15^{\rm sys.}~{\rm MeV}$ by using shell model calculations of a cross section ratio and an energy separation of the spin doublet states ($3/2^{+}_1$ and $5/2^{+}_1$). In addition, peaks that are considered to be states of [$^{8}{\rm Li}(3^{+})\otimes s_{\Lambda}=3/2^{+}_{2}, 1/2^{+}$] and [$^{8}{\rm Li}(1^{+})\otimes s_{\Lambda}=5/2^{+}_{2}, 7/2^{+}$] were observed at $E_{\Lambda}({\rm no.~2})=1.74\pm0.27^{\rm stat.}\pm0.11^{\rm sys.}~{\rm MeV}$ and $E_{\Lambda}({\rm no.~3})=3.30\pm0.24^{\rm stat.}\pm0.11^{\rm sys.}~{\rm MeV}$, respectively. The $E_{\Lambda}({\rm no.~3})$ is larger than shell model predictions by a few hundred keV, and the difference would indicate that a ${\rm ^{5}He}+t$ structure is more developed for the $3^{+}$ state than those for the $2^{+}$ and $1^{+}$ states in a core nucleus $^{8}{\rm Li}$ as a cluster model calculation suggests., Comment: 5 pages, 3 figures
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- 2021
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3. Exclusive $\pi^+$ electroproduction off the proton from low to high -t
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Basnet, S., Huber, G. M., Li, W. B., Blok, H. P., Gaskell, D., Horn, T., Aniol, K., Arrington, J., Beise, E. J., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Ent, R., Gibson, E., Holt, R. J., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P., Reinhold, J., Roche, J., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Tvaskis, V., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.
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Nuclear Experiment ,High Energy Physics - Experiment - Abstract
Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between non-perturbative and perturbative Quantum Chromodyanmics as the square of four momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the $^1$H(e,e'$\pi^+$)n reaction were measured over the -t range of 0.272 to 2.127 GeV$^2$ with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q$^2$ of 2.4 GeV$^2$ and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured $\pi^+$ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude based theoretical model, but show poor agreement with a Generalized Parton Distribution (GPD) based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t-slopes between the low and high -t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime., Comment: 9 pages, 5 figures Physical Review C, in press
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- 2019
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4. Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction
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Li, W. B., Huber, G. M., Blok, H. P., Gaskell, D., Horn, T., Semenov-Tian-Shansky, K., Pire, B., Szymanowski, L., Laget, J. -M., Aniol, K., Arrington, J., Beise, E. J., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Ent, R., Gibson, E. F., Holt, R. J., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Smith, Tadevosyan, V., Tang, L. G., Tvaskis, V., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.
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Nuclear Experiment ,High Energy Physics - Experiment ,High Energy Physics - Phenomenology ,Nuclear Theory - Abstract
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive omega electroproduction off the proton, e + p -> e' + p + omega, at central Q^2 values of 1.60, 2.45 GeV^2 , at W = 2.21 GeV. The results of our pioneering -u ~ -u min study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^2 =2.45 GeV^2 , the observed dominance of sigma_T over sigma_L, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes (TDAs): universal non-perturbative objects only accessible through backward angle kinematics.
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- 2019
5. Exclusive π+ electroproduction off the proton from low to high -t
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Basnet, S, Huber, GM, Li, WB, Blok, HP, Gaskell, D, Horn, T, Aniol, K, Arrington, J, Beise, EJ, Boeglin, W, Brash, EJ, Breuer, H, Chang, CC, Christy, ME, Ent, R, Gibson, E, Holt, RJ, Jin, S, Jones, MK, Keppel, CE, Kim, W, King, PM, Kovaltchouk, V, Liu, J, Lolos, GJ, MacK, DJ, Margaziotis, DJ, Markowitz, P, Matsumura, A, Meekins, D, Miyoshi, T, Mkrtchyan, H, Niculescu, I, Okayasu, Y, Pentchev, L, Perdrisat, C, Potterveld, D, Punjabi, V, Reimer, P, Reinhold, J, Roche, J, Sarty, A, Smith, GR, Tadevosyan, V, Tang, LG, Tvaskis, V, Volmer, J, Vulcan, W, Warren, G, Wood, SA, Xu, C, and Zheng, X
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nucl-ex ,hep-ex - Abstract
Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between nonperturbative and perturbative quantum chromodynamics as the square of four-momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the H1(e,e′π+)n reaction were measured over the -t range of 0.272 to 2.127 GeV2 with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q2 of 2.4 GeV2, and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured π+ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude-based theoretical model but show poor agreement with a generalized parton distribution-based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t slopes between the low- and high - t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime.
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- 2019
6. Exclusive π+ electroproduction off the proton from low to high −t
- Author
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Basnet, S, Huber, GM, Li, WB, Blok, HP, Gaskell, D, Horn, T, Aniol, K, Arrington, J, Beise, EJ, Boeglin, W, Brash, EJ, Breuer, H, Chang, CC, Christy, ME, Ent, R, Gibson, E, Holt, RJ, Jin, S, Jones, MK, Keppel, CE, Kim, W, King, PM, Kovaltchouk, V, Liu, J, Lolos, GJ, Mack, DJ, Margaziotis, DJ, Markowitz, P, Matsumura, A, Meekins, D, Miyoshi, T, Mkrtchyan, H, Niculescu, I, Okayasu, Y, Pentchev, L, Perdrisat, C, Potterveld, D, Punjabi, V, Reimer, P, Reinhold, J, Roche, J, Sarty, A, Smith, GR, Tadevosyan, V, Tang, LG, Tvaskis, V, Volmer, J, Vulcan, W, Warren, G, Wood, SA, Xu, C, and Zheng, X
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Nuclear and Plasma Physics ,Particle and High Energy Physics ,Physical Sciences ,nucl-ex ,hep-ex ,Nuclear and plasma physics - Abstract
Background: Measurements of exclusive meson production are a useful tool in the study of hadronic structure. In particular, one can discern the relevant degrees of freedom at different distance scales through these studies. Purpose: To study the transition between nonperturbative and perturbative quantum chromodynamics as the square of four-momentum transfer to the struck proton, -t, is increased. Method: Cross sections for the H1(e,e′π+)n reaction were measured over the -t range of 0.272 to 2.127 GeV2 with limited azimuthal coverage at fixed beam energy of 4.709 GeV, Q2 of 2.4 GeV2, and W of 2.0 GeV at the Thomas Jefferson National Accelerator Facility (JLab) Hall C. Results: The -t dependence of the measured π+ electroproduction cross section generally agrees with prior data from JLab Halls B and C. The data are consistent with a Regge amplitude-based theoretical model but show poor agreement with a generalized parton distribution-based model. Conclusion: The agreement of cross sections with prior data implies small contribution from the interference terms, and the confirmation of the change in t slopes between the low- and high - t regions previously observed in photoproduction indicates the changing nature of the electroproduction reaction in our kinematic regime.
- Published
- 2019
7. Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction
- Author
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Li, WB, Huber, GM, Blok, HP, Gaskell, D, Horn, T, Semenov-Tian-Shansky, K, Pire, B, Szymanowski, L, Laget, J-M, Aniol, K, Arrington, J, Beise, EJ, Boeglin, W, Brash, EJ, Breuer, H, Chang, CC, Christy, ME, Ent, R, Gibson, EF, Holt, RJ, Jin, S, Jones, MK, Keppel, CE, Kim, W, King, PM, Kovaltchouk, V, Liu, J, Lolos, GJ, Mack, DJ, Margaziotis, DJ, Markowitz, P, Matsumura, A, Meekins, D, Miyoshi, T, Mkrtchyan, H, Niculescu, I, Okayasu, Y, Pentchev, L, Perdrisat, C, Potterveld, D, Punjabi, V, Reimer, PE, Reinhold, J, Roche, J, Roos, PG, Sarty, A, Smith, GR, Tadevosyan, V, Tang, LG, Tvaskis, V, Volmer, J, Vulcan, W, Warren, G, Wood, SA, Xu, C, and Zheng, X
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Nuclear and Plasma Physics ,Particle and High Energy Physics ,Physical Sciences ,Jefferson Lab Fπ Collaboration ,Mathematical Sciences ,Engineering ,General Physics ,Mathematical sciences ,Physical sciences - Abstract
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e^{'}pω, at central Q^{2} values of 1.60, 2.45 GeV^{2}, at W=2.21 GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45 GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.
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- 2019
8. Separated Kaon Electroproduction Cross Section and the Kaon Form Factor from 6 GeV JLab Data
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Carmignotto, M., Ali, S., Aniol, K., Arrington, J., Barrett, B., Beise, E. J., Blok, H. P., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Dittmann, A., Ent, R., Fenker, H., Gaskell, D., Gibson, E., Holt, R. J., Horn, T., Huber, G. M., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, G., Niculescu, I., Okayasu, Y., Pegg, I., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P. E., Reinhold, J., Roche, J., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Trotta, R., Tvaskis, V., Vargas, A., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.
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Nuclear Experiment - Abstract
The $^{1}H$($e,e^\prime K^+$)$\Lambda$ reaction was studied as a function of the Mandelstam variable $-t$ using data from the E01-004 (FPI-2) and E93-018 experiments that were carried out in Hall C at the 6 GeV Jefferson Lab. The cross section was fully separated into longitudinal and transverse components, and two interference terms at four-momentum transfers $Q^2$ of 1.00, 1.36 and 2.07 GeV$^2$. The kaon form factor was extracted from the longitudinal cross section using the Regge model by Vanderhaeghen, Guidal, and Laget. The results establish the method, previously used successfully for pion analyses, for extracting the kaon form factor. Data from 12 GeV Jefferson Lab experiments are expected to have sufficient precision to distinguish between theoretical predictions, for example recent perturbative QCD calculations with modern parton distribution amplitudes. The leading-twist behavior for light mesons is predicted to set in for values of $Q^2$ between 5-10 GeV$^2$, which makes data in the few GeV regime particularly interesting. The $Q^2$ dependence at fixed $x$ and $-t$ of the longitudinal cross section we extracted seems consistent with the QCD factorization prediction within the experimental uncertainty.
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- 2018
- Full Text
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9. Experimental techniques and performance of $\Lambda$-hypernuclear spectroscopy with the $(e,e^{\prime}K^{+})$ reaction
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Gogami, T., Chen, C., Fujii, Y., Hashimoto, O., Kaneta, M., Kawama, D., Maruta, T., Matsumura, A., Nagao, S., Nakamura, S. N., Okayasu, Y., Reinhold, J., Tang, L., Tsukada, K., Wood, S. A., and Yuan, L.
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Physics - Instrumentation and Detectors ,Nuclear Experiment - Abstract
The missing-mass spectroscopy of $\Lambda$ hypernuclei via the $(e,e^{\prime}K^{+})$ reaction has been developed through experiments at JLab Halls A and C in the last two decades. For the latest experiment, E05-115 in Hall C, we developed a new spectrometer system consisting of the HKS and HES; resulting in the best energy resolution ($E_{\Lambda} \simeq0.5$-MeV FWHM) and $B_{\Lambda}$ accuracy ($B_{\Lambda}\leq0.2$ MeV) in $\Lambda$-hypernuclear reaction spectroscopy. This paper describes the characteristics of the $(e,e^{\prime}K^{+})$ reaction compared to other reactions and experimental methods. In addition, the experimental apparatus, some of the important analyses such as the semi-automated calibration of absolute energy scale, and the performance achieved in E05-115 are presented., Comment: 20 pages, 23 figures
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- 2017
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10. Separated kaon electroproduction cross section and the kaon form factor from 6 GeV JLab data
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Carmignotto, M, Ali, S, Aniol, K, Arrington, J, Barrett, B, Beise, EJ, Blok, HP, Boeglin, W, Brash, EJ, Breuer, H, Chang, CC, Christy, ME, Dittmann, A, Ent, R, Fenker, H, Gaskell, D, Gibson, E, Holt, RJ, Horn, T, Huber, GM, Jin, S, Jones, MK, Keppel, CE, Kim, W, King, PM, Kovaltchouk, V, Liu, J, Lolos, GJ, MacK, DJ, Margaziotis, DJ, Markowitz, P, Matsumura, A, Meekins, D, Miyoshi, T, Mkrtchyan, H, Niculescu, G, Niculescu, I, Okayasu, Y, Pegg, IL, Pentchev, L, Perdrisat, C, Potterveld, D, Punjabi, V, Reimer, PE, Reinhold, J, Roche, J, Sarty, A, Smith, GR, Tadevosyan, V, Tang, LG, Trotta, R, Tvaskis, V, Vargas, A, Vidakovic, S, Volmer, J, Vulcan, W, Warren, G, Wood, SA, Xu, C, and Zheng, X
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nucl-ex - Abstract
The H1(e,e′K+)Λ reaction was studied as a function of the Mandelstam variable -t using data from the E01-004 (FPI-2) and E93-018 experiments that were carried out in Hall C at the 6 GeV Jefferson Laboratory. The cross section was fully separated into longitudinal and transverse components, and two interference terms at four-momentum transfers Q2 of 1.00, 1.36, and 2.07GeV2. The kaon form factor was extracted from the longitudinal cross section using the Regge model by Vanderhaeghen et al. [Phys. Rev. C 57, 1454 (1998)PRVCAN0556-281310.1103/PhysRevC.57.1454]. The results establish the method, previously used successfully for pion analyses, for extracting the kaon form factor. Data from 12 GeV Jefferson Laboratory experiments are expected to have sufficient precision to distinguish between theoretical predictions, for example, recent perturbative QCD calculations with modern parton distribution amplitudes. The leading-twist behavior for light mesons is predicted to set in for values of Q2 between 5 and 10GeV2, which makes data in the few-GeV regime particularly interesting. The Q2 dependence at fixed x and -t of the longitudinal cross section that we extracted seems consistent with the QCD factorization prediction within the experimental uncertainty.
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- 2018
11. Spectroscopy of the neutron-rich hypernucleus $^{7}_{\Lambda}$He from electron scattering
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Gogami, T., Chen, C., Kawama, D., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Baturin, P., Badui, R., Boeglin, W., Bono, J., Brash, E., Carter, P., Chiba, A., Christy, E., Danagoulian, S., De Leo, R., Doi, D., Elaasar, M., Ent, R., Fujii, Y., Fujita, M., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Han, Y., Hashimoto, O., Horn, T., Hu, B., Hungerford, Ed. V., Jones, M., Kanda, H., Kaneta, M., Kato, S., Kawai, M., Khanal, H., Kohl, M., Liyanage, A., Luo, W., Maeda, K., Margaryan, A., Markowitz, P., Maruta, T., Matsumura, A., Maxwell, V., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Nakamura, S. N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M. I., Nunez, A., Nuruzzaman, Okayasu, Y., Petkovic, T., Pochodzalla, J., Qiu, X., Reinhold, J., Rodriguez, V. M., Samanta, C., Sawatzky, B., Seva, T., Shichijo, A., Tadevosyan, V., Tang, L., Taniya, N., Tsukada, K., Veilleux, M., Vulcan, W., Wesselmann, F. R., Wood, S. A., Yamamoto, T., Ya, L., Ye, Z., Yokota, K., Yuan, L., Zhamkochyan, S., and Zhu, L.
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Nuclear Experiment ,Nuclear Theory - Abstract
The missing mass spectroscopy of the $^{7}_{\Lambda}$He hypernucleus was performed, using the $^{7}$Li$(e,e^{\prime}K^{+})^{7}_{\Lambda}$He reaction at the Thomas Jefferson National Accelerator Facility Hall C. The $\Lambda$ binding energy of the ground state (1/2$^{+}$) was determined with a smaller error than that of the previous measurement, being $B_{\Lambda}$ = 5.55 $\pm$ 0.10(stat.) $\pm$ 0.11(sys.) MeV. The experiment also provided new insight into charge symmetry breaking in p-shell hypernuclear systems. Finally, a peak at $B_{\Lambda}$ = 3.65 $\pm$ 0.20(stat.) $\pm$ 0.11(sys.) MeV was observed and assigned as a mixture of 3/2$^{+}$ and 5/2$^{+}$ states, confirming the "gluelike" behavior of $\Lambda$, which makes an unstable state in $^{6}$He stable against neutron emission., Comment: 6 pages, 4 figures
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- 2016
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12. High Resolution Spectroscopic Study of $^{10}_{\Lambda}$Be
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Gogami, T., Chen, C., Kawama, D., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Baturin, P., Badui, R., Boeglin, W., Bono, J., Brash, E., Carter, P., Chiba, A., Christy, E., Danagoulian, S., De Leo, R., Doi, D., Elaasar, M., Ent, R., Fujii, Y., Fujita, M., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Han, Y., Hashimoto, O., Horn, T., Hu, B., Hungerford, Ed. V., Jones, M., Kanda, H., Kaneta, M., Kato, S., Kawai, M., Khanal, H., Kohl, M., Liyanage, A., Luo, W., Maeda, K., Margaryan, A., Markowitz, P., Maruta, T., Matsumura, A., Maxwell, V., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Nakamura, S. N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M. I., Nunez, A., Nuruzzaman, Okayasu, Y., Petkovic, T., Pochodzalla, J., Qiu, X., Reinhold, J., Rodriguez, V. M., Samanta, C., Sawatzky, B., Seva, T., Shichijo, A., Tadevosyan, V., Tang, L., Taniya, N., Tsukada, K., Veilleux, M., Vulcan, W., Wesselmann, F. R., Wood, S. A., Yamamoto, T., Ya, L., Ye, Z., Yokota, K., Yuan, L., Zhamkochyan, S., and Zhu, L.
- Subjects
Nuclear Experiment - Abstract
Spectroscopy of a $^{10}_{\Lambda}$Be hypernucleus was carried out at JLab Hall C using the $(e,e^{\prime}K^{+})$ reaction. A new magnetic spectrometer system (SPL+HES+HKS), specifically designed for high resolution hypernuclear spectroscopy, was used to obtain an energy spectrum with a resolution of 0.78 MeV (FWHM). The well-calibrated spectrometer system of the present experiment using the $p(e,e^{\prime}K^{+})\Lambda,\Sigma^{0}$ reactions allowed us to determine the energy levels, and the binding energy of the ground state peak (mixture of 1$^{-}$ and 2$^{-}$ states) was obtained to be B$_{\Lambda}$=8.55$\pm$0.07(stat.)$\pm$0.11(sys.) MeV. The result indicates that the ground state energy is shallower than that of an emulsion study by about 0.5 MeV which provides valuable experimental information on charge symmetry breaking effect in the $\Lambda N$ interaction., Comment: 6 figures
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- 2015
- Full Text
- View/download PDF
13. Separated Response Functions in Exclusive, Forward $\pi^{\pm}$ Electroproduction on Deuterium
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Huber, G. M., Blok, H. P., Butuceanu, C., Gaskell, D., Horn, T., Mack, D. J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Beise, E. J., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E. F., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tadevosyan, V., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., Zihlmann, B., and Collaboration, The Jefferson Lab Fpi
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Nuclear Experiment - Abstract
Background: Measurements of forward exclusive meson production at different squared four-momenta of the exchanged virtual photon, $Q^2$, 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 $\pi^-$ and $\pi^+$ 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 factor from electroproduction data. Method: Data were acquired with 2.6-5.2 GeV electron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at W=1.95 GeV, and $Q^2$=2.45 GeV$^2$ at W=2.22 GeV. There was significant coverage in $\phi$ and $\epsilon$, which allowed separation of $\sigma_{L,T,LT,TT}$. Results: $\sigma_L$ shows a clear signature of the pion pole, with a sharp rise at small -t. In contrast, $\sigma_T$ is much flatter versus t. The longitudinal/transverse ratios evolve with $Q^2$ and t, and at the highest $Q^2$=2.45 GeV$^2$ show a slight enhancement for $\pi^-$ production compared to $\pi^+$. The $\pi^-/\pi^+$ ratio for transverse photons exhibits only a small $Q^2$-dependence, following a nearly universal curve with t, with a steep transition to a value of about 0.25, consistent with s-channel quark knockout. The $\sigma_{TT}/\sigma_T$ ratio also drops rapidly with $Q^2$, qualitatively consistent with s-channel helicity conservation. The $\pi^-/\pi^+$ ratio for longitudinal photons indicates a small isoscalar contamination at W=1.95 GeV, consistent with what was observed in our earlier determination of the pion form factor at these kinematics., Comment: 25 pages, 16 figures, 6 tables
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- 2014
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14. The experiments with the High Resolution Kaon Spectrometer at JLab Hall C and the new spectroscopy of ${}^{12}_{\Lambda}\text{B}$ hypernuclei
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Tang, L., Chen, C., Gogami, T., Kawama, D., Han, Y., Yuan, L., Matsumura, A., Okayasu, Y., Seva, T., Rodriguez, V. M., Baturin, P., Acha, A., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Badui, R., Baker, O. K., Benmokhtar, F., Boeglin, W., Bono, J., Bosted, P., Brash, E., Carter, P., Carlini, R., Chiba, A., Christy, M. E., Cole, L., Dalton, M. M., Danagoulian, S., Daniel, A., De Leo, R., Dharmawardane, V., Doi, D., Egiyan, K., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Gibson, E. F., Gueye, P., Hashimoto, O., Honda, D., Horn, T., Hu, B., Hungerford, Ed V., Jayalath, C., Jones, M., Johnston, K., Kalantarians, N., Kanda, H., Kaneta, M., Kato, F., Kato, S., Kawai, M., Keppel, C., Khanal, H., Kohl, M., Kramer, L., Lan, K. J., Li, Y., Liyanage, A., Luo, W., Mack, D., Maeda, K., Malace, S., Margaryan, A., Marikyan, G., Markowitz, P., Maruta, T., Maruyama, N., Maxwell, V., Millener, D. J., Miyoshi, T., Mkrtchyan, A., Mkrtchyan, H., Motoba, T., Nagao, S., Nakamura, S. N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M. I., Nunez, A., Nuruzzaman, Nomura, H., Nonaka, K., Ohtani, A., Oyamada, M., Perez, N., Petkovic, T., Pochodzalla, J., Qiu, X., Randeniya, S., Raue, B., Reinhold, J., Rivera, R., Roche, J., Samanta, C., Sato, Y., Sawatzky, B., Segbefia, E. K., Schott, D., Shichijo, A., Simicevic, N., Smith, G., Song, Y., Sumihama, M., Tadevosyan, V., Takahashi, T., Taniya, N., Tsukada, K., Tvaskis, V., Veilleux, M., Vulcan, W., Wells, S., Wesselmann, F. R., Wood, S. A., Yamamoto, T., Yan, C., Ye, Z., Yokota, K., Zhamkochyan, S., and Zhu, L.
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Nuclear Experiment - Abstract
Since the pioneering experiment, E89-009 studying hypernuclear spectroscopy using the $(e,e^{\prime}K^+)$ reaction was completed, two additional experiments, E01-011 and E05-115, were performed at Jefferson Lab. These later experiments used a modified experimental design, the "tilt method", to dramatically suppress the large electromagnetic background, and allowed for a substantial increase in luminosity. Additionally, a new kaon spectrometer, HKS (E01-011), a new electron spectrometer, HES, and a new splitting magnet were added to produce precision, high-resolution hypernuclear spectroscopy. These two experiments, E01-011 and E05-115, resulted in two new data sets, producing sub-MeV energy resolution in the spectra of ${}^{7}_{\Lambda}\text{He}$, ${}^{12}_{\Lambda}\text{B}$ and ${}^{28}_{\Lambda}\text{Al}$ and ${}^{7}_{\Lambda}\text{He}$, ${}^{10}_{\Lambda}\text{Be}$, ${}^{12}_{\Lambda}\text{B}$ and ${}^{52}_{\Lambda}\text{V}$. All three experiments obtained a ${}^{12}_{\Lambda}\text{B}$, spectrum, which is the most characteristic $p$-shell hypernucleus and is commonly used for calibration. Independent analyses of these different experiments demonstrate excellent consistency and provide the clearest level structure to date of this hypernucleus as produced by the $(e,e^{\prime}K^+)$ reaction. This paper presents details of these experiments, and the extraction and analysis of the observed ${}^{12}_{\Lambda}\text{B}$ spectrum.
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- 2014
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15. Separated Response Function Ratios in Exclusive, Forward pi^{+/-} Electroproduction
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Huber, G. M., Blok, H. P., Butuceanu, C., Gaskell, D., Horn, T., Mack, D. J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Beise, E. J., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E. F., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P. E., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tadevosyan, V., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
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Nuclear Experiment - Abstract
The study of exclusive $\pi^{\pm}$ electroproduction on the nucleon, including separation of the various structure functions, is of interest for a number of reasons. The ratio $R_L=\sigma_L^{\pi^-}/\sigma_L^{\pi^+}$ 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 $R_T=\sigma_T^{\pi^-}/\sigma_T^{\pi^+}$ 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 approach to pQCD than the individual cross sections. We have performed the first complete separation of the four unpolarized electromagnetic structure functions above the dominant resonances in forward, exclusive $\pi^{\pm}$ electroproduction on the deuteron at central $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at $W$=1.95 GeV, and $Q^2=2.45$ GeV$^2$ at $W$=2.22 GeV. Here, we present the $L$ and $T$ cross sections, with emphasis on $R_L$ and $R_T$, and compare them with theoretical calculations. Results for the separated ratio $R_L$ indicate dominance of the pion-pole diagram at low $-t$, while results for $R_T$ are consistent with a transition between pion knockout and quark knockout mechanisms., Comment: 6 pages, 3 figures
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- 2014
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16. Direct Measurements of the Lifetime of Heavy Hypernuclei
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Qiu, X., Tang, L., Margaryan, A., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Badui, R., Baturin, P., Boeglin, W., Bono, J., Brash, E., Carter, P., Chen, C., Chen, X., Chiba, A., Christy, E., Dalton, M. M., Danagoulian, S., De Leo, R., Doi, D., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Gogami, T., Hashimoto, O., Horn, T., Hu, B., Hungerford, E. V., Jones, M., Kanda, H., Kaneta, M., Kawai, M., Kawama, D., Khanal, H., Kohl, M., Liyanage, A., Luo, W., Maeda, K., Markowitz, P., Maruta, T., Matsumura, A., Maxwell, V., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Nakamura, S. N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M. I., Nunez, A., Nuruzzaman, Okayasu, Y., Petkovic, T., Pochodzalla, J., Reinhold, J., Rodriguez, V. M., Samanta, C., Sawatzky, B., Seva, T., Shichijo, A., Tadevosyan, V., Taniya, N., Tsukada, K., Veilleux, M., Vulcan, W., Wesselmann, F. R., Wood, S. A., Ya, L., Yamamoto, T., Ye, Z., Yokota, K., Yuan, L., Zhamkochyan, S., and Zhu, L.
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Nuclear Experiment - Abstract
The lifetime of a Lambda particle embedded in a nucleus (hypernucleus) decreases from that of free Lambda decay due to the opening of the Lambda N to NN weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. The present paper reports a direct measurement of the lifetime of medium-heavy hypernuclei produced with a photon-beam from Fe, Cu, Ag, and Bi targets. The recoiling hypernuclei were detected by a fission fragment detector using low-pressure multi-wire proportional chambers. The experiment agrees remarkably well with the only previously-measured single-species heavy-hypernucleus lifetime, that of Fe56_Lambda at KEK, and has significantly higher precision. The experiment disagrees with the measured lifetime of an unknown combination of heavy hypernuclei with 180
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- 2012
17. Observation of the Helium 7 Lambda hypernucleus by the (e,e'K+) reaction
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Nakamura, S. N., Matsumura, A., Okayasu, Y., Seva, T., Rodriguez, V. M., Baturin, P., Yuan, L., Acha, A., Ahmidouch, A., Androic, D., Asaturyan, A., Asaturyan, R., Baker, O. K., Benmokhtar, F., Bosted, P., Carlini, R., Chen, C., Christy, M., Cole, L., Danagoulian, S., Daniel, A., Dharmawardane, V., Egiyan, K., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gan, L., Gaskell, D., Gasparian, A., Gibson, E. F., Gogami, T., Gueye, P., Han, Y., Hashimoto, O., Hiyama, E., Honda, D., Horn, T., Hu, B., Hungerford, Ed V., Jayalath, C., Jones, M., Johnston, K., Kalantarians, N., Kanda, H., Kaneta, M., Kato, F., Kato, S., Kawama, D., Keppel, C., Lan, K. J., Luo, W., Mack, D., Maeda, K., Malace, S., Margaryan, A., Marikyan, G., Markowitz, P., Maruta, T., Maruyama, N., Miyoshi, T., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Navasardyan, T., Niculescu, G., Niculescu, M. -I., Nomura, H., Nonaka, K., Ohtani, A., Oyamada, M., Perez, N., Petkovic, T., Randeniya, S., Reinhold, J., Roche, J., Sato, Y., Segbefia, E. K., Simicevic, N., Smith, G., Song, Y., Sumihama, M., Tadevosyan, V., Takahashi, T., Tang, L., Tsukada, K., Tvaskis, V., Vulcan, W., Wells, S., Wood, S. A., Yan, C., and Zhamkochyan, S.
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Nuclear Experiment - Abstract
An experiment with a newly developed high-resolution kaon spectrometer (HKS) and a scattered electron spectrometer with a novel configuration was performed in Hall C at Jefferson Lab (JLab). The ground state of a neutron-rich hypernucleus, He 7 Lambda, was observed for the first time with the (e,e'K+) reaction with an energy resolution of ~0.6 MeV. This resolution is the best reported to date for hypernuclear reaction spectroscopy. The he 7 Lambda binding energy supplies the last missing information of the A=7, T=1 hypernuclear iso-triplet, providing a new input for the charge symmetry breaking (CSB) effect of \Lambda N potential., Comment: 5 pages, 4 figures, submitted to PRL
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- 2012
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18. Nuclear transparency and effective kaon-nucleon cross section from the A(e, e'K+) reaction
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Nuruzzaman, Dutta, D., Arrington, J., Asaturyan, R., Benmokhtar, F., Boeglin, W., Bosted, P., Bruell, A., Clasie, B., Christy, M. E., Chudakov, E., Dalton, M. M., Daniel, A., Day, D., Fassi, L. El, Ent, R., Fenker, H. C., Ferrer, J., Fomin, N., Gao, H., Garrow, K., Gaskel, D., Gray, C., Horn, T., Huber, G. M., Jones, M. K., Kalantarians, N., Keppel, C. E., Kramer, K., Li, Y., Liang, Y., Lung, A. F., Malace, S., Markowitz, P., Matsumura, A., Meekins, D. G., Mertens, T., Miyoshi, T., Mkrtchyan, H., Monson, R., Navasardyan, T., Niculescu, G., Niculescu, I., Okayasu, Y., Opper, A. K., Perdrisat, C., Punjabi, V., Qian, X., Rauf, A. W., Rodriquez, V. M., Rohe, D., Seely, J., Segbefia, E., Smith, G. R., Sumihama, M., Tadevosyan, V., Tang, L., Tvaskis, V., Vulcan, W. F., Wesselmann, F. R., Wood, S. A., Yuan, L., and Zheng, X. C.
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Nuclear Experiment ,Nuclear Theory - Abstract
We have determined the transparency of the nuclear medium to kaons from $A(e,e^{'} K^{+})$ measurements on $^{12}$C, $^{63}$Cu, and $^{197}$Au targets. The measurements were performed at the Jefferson Laboratory and span a range in four-momentum-transfer squared Q$^2$=1.1 -- 3.0 GeV$^2$. The nuclear transparency was defined as the ratio of measured kaon electroproduction cross sections with respect to deuterium, ($\sigma^{A}/\sigma^{D}$). We further extracted the atomic number ($A$) dependence of the transparency as parametrized by $T= (A/2)^{\alpha-1}$ and, within a simple model assumption, the in-medium effective kaon-nucleon cross sections. The effective cross sections extracted from the electroproduction data are found to be smaller than the free cross sections determined from kaon-nucleon scattering experiments, and the parameter $\alpha$ was found to be significantly larger than those obtained from kaon-nucleus scattering. We have included similar comparisons between pion- and proton-nucleon effective cross sections as determined from electron scattering experiments, and pion-nucleus and proton-nucleus scattering data., Comment: 7 pages, 5 figures
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- 2011
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19. Scaling of the F_2 structure function in nuclei and quark distributions at x>1
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Fomin, N., Arrington, J., Day, D. B., Gaskell, D., Daniel, A., Seely, J., Asaturyan, R., Benmokhtar, F., Boeglin, W., Boillat, B., Bosted, P., Bruell, A., Bukhari, M. H. S., Christy, M. E., Chudakov, E., Clasie, B., Connell, S. H., Dalton, M. M., Dutta, D., Ent, R., Fassi, L. El, Fenker, H., Filippone, B. W., Garrow, K., Hill, C., Holt, R. J., Horn, T., Jones, M. K., Jourdan, J., Kalantarians, N., Keppel, C. E., Kiselev, D., Kotulla, M., Lindgren, R., Lung, A. F., Malace, S., Markowitz, P., McKee, P., Meekins, D. G., Miyoshi, T., Mkrtchyan, H., Navasardyan, T., Niculescu, G., Okayasu, Y., Opper, A. K., Perdrisat, C., Potterveld, D. H., Punjabi, V., Qian, X., Reimer, P. E., Roche, J., Rodriguez, V. M., Rondon, O., Schulte, E., Segbefia, E., Slifer, K., Smith, G. R., Solvignon, P., Tadevosyan, V., Tajima, S., Tang, L., Testa, G., Trojer, R., Tvaskis, V., Vulcan, W. F., Wasko, C., Wesselmann, F. R., Wood, S. A., Wright, J., and Zheng, X.
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Nuclear Experiment - Abstract
We present new data on electron scattering from a range of nuclei taken in Hall C at Jefferson Lab. For heavy nuclei, we observe a rapid falloff in the cross section for $x>1$, which is sensitive to short range contributions to the nuclear wave-function, and in deep inelastic scattering corresponds to probing extremely high momentum quarks. This result agrees with higher energy muon scattering measurements, but is in sharp contrast to neutrino scattering measurements which suggested a dramatic enhancement in the distribution of the `super-fast' quarks probed at x>1. The falloff at x>1 is noticeably stronger in ^2H and ^3He, but nearly identical for all heavier nuclei., Comment: 5 pages, 4 figures, to be submitted to physical review
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- 2010
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20. New measurements of the EMC effect in very light nuclei
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Seely, J., Daniel, A., Gaskell, D., Arrington, J., Fomin, N., Solvignon, P., Asaturyan, R., Benmokhtar, F., Boeglin, W., Boillat, B., Bosted, P., Bruell, A., Bukhari, M. H. S., Christy, M. E., Clasie, B., Connell, S., Dalton, M., Day, D., Dunne, J., Dutta, D., Fassi, L. El, Ent, R., Fenker, H., Filippone, B. W., Gao, H., Hill, C., Holt, R. J., Horn, T., Hungerford, E., Jones, M. K., Jourdan, J., Kalantarians, N., Keppel, C. E., Kiselev, D., Kotulla, M., Lee, C., Lung, A. F., Malace, S., Meekins, D. G., Mertens, T., Mkrtchyan, H., Navasardyan, T., Niculescu, G., Niculescu, I., Nomura, H., Okayasu, Y., Opper, A. K., Perdrisat, C., Potterveld, D. H., Punjabi, V., Qian, X., Reimer, P. E., Roche, J., Rodriguez, V. M., Rondon, O., Schulte, E., Segbefia, E., Slifer, K., Smith, G. R., Tadevosyan, V., Tajima, S., Tang, L., Testa, G., Trojer, R., Tvaskis, V., Vulcan, W. F., Wesselmann, F. R., Wood, S. A., Wright, J., Yuan, L., and Zheng, X.
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Nuclear Experiment ,High Energy Physics - Phenomenology - Abstract
New Jefferson Lab data are presented on the nuclear dependence of the inclusive cross section from 2H, 3He, 4He, 9Be and 12C for 0.3
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- 2009
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21. Control survey and analysis for the KEK e−/e+ injector linac
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Okayasu, Y., primary, Suwada, T., additional, Kakihara, K., additional, and Tanaka, M., additional
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- 2023
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22. Charged pion form factor between $Q^2$=0.60 and 2.45 GeV$^2$. I. Measurements of the cross section for the ${^1}$H($e,e'\pi^+$)$n$ reaction
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Blok, H. P., Horn, T., Huber, G. M., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Fenker, H., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Liang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
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Nuclear Experiment - Abstract
Cross sections for the reaction ${^1}$H($e,e'\pi^+$)$n$ were measured in Hall C at Thomas Jefferson National Accelerator Facility (JLab) using the CEBAF high-intensity, continous electron beam in order to determine the charged pion form factor. Data were taken for central four-momentum transfers ranging from $Q^2$=0.60 to 2.45 GeV$^2$ at an invariant mass of the virtual photon-nucleon system of $W$=1.95 and 2.22 GeV. The measured cross sections were separated into the four structure functions $\sigma_L$, $\sigma_T$, $\sigma_{LT}$, and $\sigma_{TT}$. The various parts of the experimental setup and the analysis steps are described in detail, including the calibrations and systematic studies, which were needed to obtain high precision results. The different types of systematic uncertainties are also discussed. The results for the separated cross sections as a function of the Mandelstam variable $t$ at the different values of $Q^2$ are presented. Some global features of the data are discussed, and the data are compared with the results of some model calculations for the reaction ${^1}$H($e,e'\pi^+$)$n$., Comment: 26 pages, 23 figures
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- 2008
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23. Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II. Determination of, and results for, the pion form factor
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Huber, G. M., Blok, H. P., Horn, T., Beise, E. J., Gaskell, D., Mack, D. J., Tadevosyan, V., Volmer, J., Abbott, D., Aniol, K., Anklin, H., Armstrong, C., Arrington, J., Assamagan, K., Avery, S., Baker, O. K., Barrett, B., Bochna, C., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Chant, N., Christy, M. E., Dunne, J., Eden, T., Ent, R., Gibson, E., Gilman, R., Gustafsson, K., Hinton, W., Holt, R. J., Jackson, H., Jin, S., Jones, M. K., Keppel, C. E., Kim, P. H., Kim, W., King, P. M., Klein, A., Koltenuk, D., Kovaltchouk, V., Kiang, M., Liu, J., Lolos, G. J., Lung, A., Margaziotis, D. J., Markowitz, P., Matsumura, A., McKee, D., Meekins, D., Mitchell, J., Miyoshi, T., Mkrtchyan, H., Mueller, B., Niculescu, G., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Pitz, D., Potterveld, D., Punjabi, V., Qin, L. M., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Shin, I. K., Smith, G. R., Stepanyan, S., Tang, L. G., Tvaskis, V., van der Meer, R. L. J., Vansyoc, K., Van Westrum, D., Vidakovic, S., Vulcan, W., Warren, G., Wood, S. A., Xu, C., Yan, C., Zhao, W. -X., Zheng, X., and Zihlmann, B.
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Nuclear Experiment - Abstract
The charged pion form factor, Fpi(Q^2), is an important quantity which can be used to advance our knowledge of hadronic structure. However, the extraction of Fpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is inherently model dependent. Therefore, a detailed description of the extraction of the charged pion form factor from electroproduction data obtained recently at Jefferson Lab is presented, with particular focus given to the dominant uncertainties in this procedure. Results for Fpi are presented for Q^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically below the monopole parameterization that describes the low Q^2 data used to determine the pion charge radius. The pion form factor can be calculated in a wide variety of theoretical approaches, and the experimental results are compared to a number of calculations. This comparison is helpful in understanding the role of soft versus hard contributions to hadronic structure in the intermediate Q^2 regime., Comment: 18 pages, 11 figures
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- 2008
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24. Photoproduction of neutral kaons on the liquid deuterium target in the threshold region
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Tsukada, K., Takahashi, T., Watanabe, T., Fujii, Y., Futatsukawa, K., Hashimoto, O., Hirose, K., Ito, K., Kameoka, S., Kanda, H., Maeda, K., Matsumura, A., Miura, Y., Miyase, H., Nakamura, S. N., Nomura, H., Nonaka, K., Osaka, T., Okayasu, Y., Tamura, H., Tsubota, H., Ukai, M., Yamauchi, H., Wakamatsu, M., Ishikawa, T., Kinoshita, T., Miyahara, F., Nakabayashi, T., Shimizu, H., Tamae, T., Yamazaki, H., Sasaki, A., Konno, O., Bydzovsky, P., and Sotona, M.
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Nuclear Experiment - Abstract
The photoproduction process of neutral kaons on a liquid deuterium target is investigated near the threshold region, Egamma = 0.8-1.1 GeV. K0 events are reconstructed from positive and negative pions, and differential cross sections are derived. Experimental momentum spectra are compared with those calculated in the spectator model using a realistic deuteron wave function. Elementary amplitudes as given by recent isobar models and a simple phenomenological model are used to study the effect of the new data on the angular behavior of the elementary cross section. The data favor a backward-peaked angular distribution of the elementary n(gamma,K0)Lambda process, which provides additional constraints on current models of kaon photoproduction. The present study demonstrates that the n(gamma,K0)Lambda reaction can provide key information on the mechanism of the photoproduction of strangeness., Comment: 11 pages, 13 figures
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- 2007
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25. Photo-production of neutral kaons on 12C in the threshold region
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Watanabe, T., Bydžovský, P., Dobashi, K., Endo, S., Fujii, Y., Hashimoto, O., Ishikawa, T., Itoh, K., Kanda, H., Katoh, M., Kinoshita, T., Konno, O., Maeda, K., Matsumura, A., Miyahara, F., Miyase, H., Miyoshi, T., Mizunuma, K., Miura, Y., Nakamura, S. N., Nomura, H., Okayasu, Y., Osaka, T., Oyamada, M., Sasaki, A., Satoh, T., Shimizu, H., Sotona, M., Takahashi, T., Tamae, T., Tamura, H., Terasawa, T., Tsubota, H., Tsukada, K., Ukai, M., Wakamatsu, M., Yamauchi, H., and Yamazaki, H.
- Subjects
Nuclear Experiment - Abstract
Kaon photo-production process on $^{12}$C has been studied by measuring neutral kaons in a photon energy range of 0.8$-$1.1 GeV. Neutral kaons were identified by the invariant mass constructed from two charged pions emitted in the $K^{0}_{S}\to\pi^{+}\pi^{-}$ decay channel. The differential cross sections as well as the integrated ones in the threshold photon energy region were obtained. The obtained momentum spectra were compared with a Spectator model calculation using elementary amplitudes of kaon photo-production given by recent isobar models. Present result provides, for the first time, the information on $n(\gamma,K^{0})\Lambda$ reaction which is expected to play an important role to construct models for strangeness production by the electromagnetic interaction. Experimental results show that cross section of $^{12}{\rm C}(\gamma,K^0)$ is of the same order to that of $^{12}{\rm C}(\gamma,K^+)$ and suggest that slightly backward $K^0$ angular distribution is favored in the $\gamma n\to K^0\Lambda$ process., Comment: 6 pages, 8 figures
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- 2006
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26. Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45 (GeV/c)2
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Fpi2 collaboration, Horn, T., Aniol, K., Arrington, J., Barrett, B., Beise, E. J., Blok, H. P., Boeglin, W., Brash, E. J., Breuer, H., Chang, C. C., Christy, M. E., Ent, R., Gaskell, D., Gibson, E., Holt, R. J., Huber, G. M., Jin, S., Jones, M. K., Keppel, C. E., Kim, W., King, P. M., Kovaltchouk, V., Liu, J., Lolos, G. J., Mack, D. J., Margaziotis, D. J., Markowitz, P., Matsumura, A., Meekins, D., Miyoshi, T., Mkrtchyan, H., Niculescu, I., Okayasu, Y., Pentchev, L., Perdrisat, C., Potterveld, D., Punjabi, V., Reimer, P., Reinhold, J., Roche, J., Roos, P. G., Sarty, A., Smith, G. R., Tadevosyan, V., Tang, L. G., Tvaskis, V., Vidakovic, S., Volmer, J., Vulcan, W., Warren, G., Wood, S. A., Xu, C., and Zheng, X.
- Subjects
Nuclear Experiment - Abstract
The H(e,e'pi+)n cross section was measured at four-momentum transfers of Q2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of W=2.22 GeV. The charged pion form factor (F_pi) was extracted from the data by comparing the separated longitudinal pion electroproduction cross section to a Regge model prediction in which F_pi is a free parameter. The results indicate that the pion form factor deviates from the charge-radius constrained monopole form at these values of Q2 by one sigma, but is still far from its perturbative Quantum Chromo-Dynamics prediction., Comment: 4 pages, 3 figures, submitted to Physical Review Letters
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- 2006
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27. Coincidence Measurement of the Nonmesonic Weak Decay of ^{12}_{Lambda}C
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Kim, M. J., Ajimura, S., Aoki, K., Banu, A., Bhang, H., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Shin, S., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We have measured the angular correlation of the pair nucleons np and nn emitted from the nonmesonic weak decay (NMWD) of ^{12}_{Lambda}C produced via the (pi^+,K^+) reaction in coincidence measurement. The Lambda p -> np and Lambda n -> nn modes were clearly identified by measuring the back-to-back correlation of the emitted nucleon pairs which is the characteristic of two-body kinematics. From the measured nucleon pair numbers N_{nn} and N_{np}, the ratio Gamma_n/Gamma_p of the partial decay widths Gamma_n(Lambda n -> nn) and Gamma_p(Lambda p -> np) of ^{12}_{Lambda}C was extracted to be 0.51+-0.13(stat) +- 0.05(syst); this result is almost free from the ambiguity due to the nuclear final state interaction and 3-body decay process, which were inherent in the previous results. The obtained Gamma_n/Gamma_p ratio of ^{12}_{Lambda}C (p-shell) is close to that of ^5_{Lambda}He (s-shell). The results are consistent with those of recent theoretical calculations., Comment: 13 pages, 4figures, 1 table,re-submitted to Physics Letters B
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- 2006
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28. Exclusive proton asymmetry measurement in non-mesonic weak decay of polarized 5_Lambda_He
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Maruta, T., Ajimura, S., Aoki, K., Banu, A., Bhang, H., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
The asymmetry parameter alpha_p^NM for a proton exclusively emitted in the Lambda p -> np process was, for the first time, measured in the non-mesonic weak decay of a polarized 5_La,bda_He hypernucleus by selecting the proton-neutron pairs emitted in the back-to-back kinematics. The highly polarized 5_Lambda_He was abundantly produced with the (pi+,K+) reaction at 1.05GeV/c in the scattering angular range of +-15$ degrees. The obtained value alpha_p^NM=0.31+-0.22, as well as that for inclusive protons, alpha_p^NM=0.11+-0.08+-0.04, largely contradicts recent theoretical values of around -0.6, although these calculations well reproduce the branching ratios of non-mesonic weak decay., Comment: 4pages, 2 figures, submitted to Physical Review Letters
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- 2005
29. Exclusive Measurement of the Nonmesonic Weak Decay of ^{5}_{\Lambda}He Hypernucleus
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Kang, B. H., Ajimura, S., Aoki, K., Banu, A., Bhang, H., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kim, E. H., Kim, J. H., Kim, M. J., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay (NMWD) of ^{5}_{\Lambda}He formed via the ^{6}Li(\pi^+,K^+) reaction. The energies of two nucleons and the pair number distributions in the opening angle between them were measured. In both np and nn pairs, we observed a clean back-to-back correlation coming from the two-body decay of \Lambda p --> n p and \Lambda n --> n n, respectively. The ratio of the nucleon pair numbers was N_{nn}/N_{np}=0.45 \pm 0.11(stat)\pm 0.03(syst) in the kinematic region of cos(theta_{NN}) < -0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of \Gamma(\Lambda p --> np)/\Gamma(\Lambda n --> nn). The ratio is consistent with recent theoretical calculations based on the heavy meson/direct quark exchange picture., Comment: Submitted to Phys. Rev. lett., 4 pages, 3 figures
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- 2005
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30. Experimental techniques and performance of [formula omitted]-hypernuclear spectroscopy with the [formula omitted] reaction
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Gogami, T., Chen, C., Fujii, Y., Hashimoto, O., Kaneta, M., Kawama, D., Maruta, T., Matsumura, A., Nagao, S., Nakamura, S.N., Okayasu, Y., Reinhold, J., Tang, L., Tsukada, K., Wood, S.A., and Yuan, L.
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- 2018
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31. Direct measurements of the lifetime of medium-heavy hypernuclei
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Qiu, X., Tang, L., Chen, C., Margaryan, A., Wood, S.A., Achenbach, P., Ahmidouch, A., Albayrak, I., Androic, D., Asaturyan, A., Asaturyan, R., Ates, O., Badui, R., Baturin, P., Boeglin, W., Bono, J., Brash, E., Carter, P., Chen, X., Chiba, A., Christy, M.E., Dalton, M.M., Danagoulian, S., De Leo, R., Doi, D., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Gogami, T., Hashimoto, O., Horn, T., Hu, B., Hungerford, Ed V., Jones, M., Kanda, H., Kaneta, M., Kawama, D., Khanal, H., Kohl, M., Liyanage, A., Luo, W., Maeda, K., Markowitz, P., Marikyan, G., Maruta, T., Matsumura, A., Maxwell, V., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Nakamura, S.N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M.I., Nunez, A., Nuruzzaman, Okayasu, Y., Petkovic, T., Pochodzalla, J., Reinhold, J., Rodriguez, V.M., Samanta, C., Sawatzky, B., Seva, T., Shichijo, A., Tadevosyan, V., Taniya, N., Tsukada, K., Veilleux, M., Vulcan, W., Wesselmann, F.R., Yamamoto, T., Ye, Z., Yokota, K., Yuan, L., Zhamkochyan, S., and Zhu, L.
- Published
- 2018
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32. Nucleon-nucleon coincidence measurement in the non-mesonic weak decay of 5_Lambda-He and 12_Lambda-C hypernuclei
- Author
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Okada, S., Ajimura, S., Aoki, K., Banu, A., Bhang, H. C., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We have measured both yields of neutron-proton and neutron-neutron pairs emitted from the non-mesonic weak decay process of 5_Lambda-He and 12_Lambda-C hypernuclei produced via the (pi^+,K^+) reaction for the first time. We observed clean back-to-back correlation of the np- and nn-pairs in the coincidence spectra for both hypernuclei. The ratio of those back-to-back pair yields, Nnn / Nnp, must be close to the ratio of neutron- and proton-induced decay widths of the decay, Gn(Lambda n -> nn)/Gp(Lambda p -> np). The obtained ratios for each hypernuclei support recent calculations based on short-range interactions., Comment: 4 pages, 1 figure, International Nuclear Physics Conference (INPC 2004), Goteborg, Sweden, June 27 - July 2, 2004, to appear in Nuclear Physics A
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- 2004
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33. Neutron and proton energy spectra from the non-mesonic weak decays of 5_Lambda-He and 12_Lambda-C
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Okada, S., Ajimura, S., Aoki, K., Banu, A., Bhang, H. C., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We have simultaneously measured the energy spectra of neutrons and protons emitted in the non-mesonic weak decays of 5_Lambda-He and 12_Lambda-C hypernuclei produced via the (pi^+,k^+) reaction with much higher statistics over those of previous experiments. The neutron-to-proton yield ratios for both hypernuclei at a high energy threshold (60 MeV) were approximately equal to two, which suggests that the ratio of the neutron- and proton-induced decay channels, Gn(Lambda n -> nn)/Gp(Lambda p -> np), is about 0.5. In the neutron energy spectra, we found that the yield of the low-energy component is unexpectedly large, even for 5_Lambda-He., Comment: 13pages, 4figures, submitted to Physics Letters B
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- 2004
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34. Measurement of the $\pi^-$ decay width of $^5_\Lambda$He
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Kameoka, S., Ajimura, S., Aoki, K., Banu, A., Bhang, H. C., Fukuda, T., Hashimoto, O., Hwang, J. I., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We have precisely measured $\Lambda \to p\pi^-$ decay width of \5LHe and demonstrated significantly larger $\alpha$ -$\Lambda$ overlap than expected from the central repulsion $\alpha$-$\Lambda$ potential, which is derived from YNG \Lambda$-nucleon interaction., Comment: 4 pages, 3 figures
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- 2004
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35. pi^0 decay branching ratios of 5_Lambda-He and 12_Lambda-C hypernuclei
- Author
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Okada, S., Ajimura, S., Aoki, K., Banu, A., Bhang, H. C., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We precisely measured pi^0 branching ratios of 5_Lambda-He and 12_Lambda-C hypernuclei produced via (pi^+,k^+) reaction. Using these pi^0 branching ratios with the pi^- branching ratios and the lifetimes, we obtained the pi^0 decay widths and the non-mesonic weak decay widths at high statistics with the accuracy of ~5 % (stat) for both hypernuclei., Comment: 4pages, 4figures, International Conference on Hypernuclear and Strange Particle Physics (HYP2003)
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- 2004
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36. Proton asymmetry in non-mesonic weak decay of light hypernuclei
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Maruta, T., Ajimura, S., Aoki, K., Banu, A., Bhang, H., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., and Yim, H. J.
- Subjects
Nuclear Experiment - Abstract
We have obtained the decay asymmetry parameters in non-mesonic weak decay of polarized Lambda-hypernuclei by measuring the proton asymmetry. The polarized Lambda-hypernuclei, 5_Lambda-He, 12_Lambda-C, and 11_Lambda-B, were produced in high statistics via the (pi^+,k^+) reaction at 1.05 GeV/c in the forward angles. Preliminary analysis shows that the decay asymmetry parameters are very small for these s-shell and p-shell hypernuclei., Comment: 4pages, 4figures, International Conference on Hypernuclear and Strange Particle Physics (HYP2003)
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- 2004
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37. Modification of Beam Transport Line Design for Simultaneous Top-up Injection to PF and PF-AR.
- Author
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Higashi, N, Mitsuda, C, Nagahashi, S, Harada, K, Nogami, T, Uchiyama, T, Nakamura, N, Honda, T, Satoh, M, Okayasu, Y, and Enomoto, Y
- Published
- 2023
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38. Achievement of 200,000 hours of operation at KEK 7-GeV electron 4-GeV positron injector linac
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Furukawa, K, primary, Akemoto, M, additional, Arakawa, D, additional, Arakida, Y, additional, Bando, Y, additional, Ego, H, additional, Enomoto, Y, additional, Higo, T, additional, Honma, H, additional, Iida, N, additional, Kakihara, K, additional, Kamitani, T, additional, Katagiri, H, additional, Kawamura, M, additional, Matsumoto, S, additional, Matsumoto, T, additional, Matsushita, H, additional, Mikawa, K, additional, Miura, T, additional, Miyahara, F, additional, Nakajima, H, additional, Natsui, T, additional, Ogawa, Y, additional, Ohsawa, S, additional, Okayasu, Y, additional, Oogoe, T, additional, Rehman, M A, additional, Satake, I, additional, Satoh, M, additional, Seimiya, Y, additional, Shidara, T, additional, Shirakawa, A, additional, Someya, H, additional, Suwada, T, additional, Tanaka, M, additional, Wang, D, additional, Yano, Y, additional, Yokoyama, K, additional, Yoshida, M, additional, Yoshimoto, T, additional, Zhang, R, additional, and Zhou, X, additional
- Published
- 2023
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39. Control survey and analysis for the KEK e−/e+ injector linac.
- Author
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Okayasu, Y., Suwada, T., Kakihara, K., and Tanaka, M.
- Subjects
- *
INJECTORS , *LINEAR accelerators , *DATA analysis , *COMPUTER simulation , *FIDUCIAL markers (Imaging systems) - Abstract
A control survey technique using a laser tracker and a digital level was introduced to the KEK e−/e+ injector linac in 2020. Control surveys are continuously demonstrated during the machine's downtimes every summer. Analysis of the two-year data reproduces their trends in terms of the fiducial points on the beam line. In our paper, we report on systematic coordinates and their error distributions evaluated by a control survey, compare them with a numerical survey simulation, and discuss newly encountered issues. [ABSTRACT FROM AUTHOR]
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- 2023
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40. Observation of the 7 MeV excited spin-flip and non-spin-flip partners in Λ 16O by λ-ray spectroscopy
- Author
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Ukai, M., Ajimura, S., Akikawa, H., Alburger, D. E., Banu, A., Chrien, R. E., Franklin, G. B., Franz, J., Hashimoto, O., Hayakawa, T., Hotchi, H., Imai, K., Kishimoto, T., May, M., Millener, D. J., Minami, S., Miura, Y., Miyoshi, T., Mizunuma, K., Nagae, T., Nakamura, S. N., Nakazawa, K., Okayasu, Y., Pile, P., Quinn, B. P., Rusek, A., Sato, Y., Sutter, R., Takahashi, H., Tang, L., Tamura, H., Tanida, K., Yuan, L., Zhou, S. H., Pochodzalla, Josef, editor, and Walcher, Thomas, editor
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- 2007
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41. The quenching of nucleon yields in the nonmesonic weak decay of Λ-hypernuclei and the three-body weak decay process
- Author
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Bhang, H., Ajimura, S., Aoki, K., Banu, A., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Shin, S., Takahashi, T., Tamura, H., Tanida, K., Toyota, A., Tsukada, K., Watanabe, T., Yim, H. J., Pochodzalla, Josef, editor, and Walcher, Thomas, editor
- Published
- 2007
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42. Decay asymmetry in non-mesonic weak decay of light Λ-hypernuclei
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Maruta, T., Ajimura, S., Aoki, K., Banu, A., Bhang, H., Fukuda, T., Hashimoto, O., Hwang, I., Kameoka, S., Kang, B. H., Kim, E. H., Kim, J. H., Kim, M. J., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tsukada, K., Watanabe, T., Pochodzalla, Josef, editor, and Walcher, Thomas, editor
- Published
- 2007
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- View/download PDF
43. Coincidence measurement of the weak decay of 12ΛC and the three-body weak decay process (J-PARC 50GeV PS E18)
- Author
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Kim, M., Ajimura, S., Aoki, K., Banu, A., Bhang, H., Fukuda, T., Hashimoto, O., Hwang, J.I., Kameoka, S., Kang, B.H., Kim, E., Kim, J.H., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S.N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P.K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tshoo, K., Tsukada, K., Watanabe, T., and Yim, H.J.
- Published
- 2010
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44. Spectroscopy of A=9 hyperlithium with the (e,eK+) reaction
- Author
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Gogami, T., Chen, C., Kawama, D., Achenbach, P., Ahmidouch, A., Albayrak, I., Androić, Darko, Asaturyan, A., Asaturyan, R., Ates, O., Baturin, P., Badui, R., Boeglin, W., Bono, J., Brash, E., Carter, P., Chiba, A., Christy, E., Danagoulian, S., De Leo, R., Doi, D., Elaasar, M., Ent, R., Fujii, Y., Fujita, M., Furic, Miroslav, Gabrielyan, M., Gan, L., Garibaldi, F., Gaskell, D., Gasparian, A., Han, Y., Hashimoto, O., Horn, T., Hu, B., Hungerford, Ed.V., Jones, M., Kanda, H., Kaneta, M., Kato, S., Kawai, M., Khanal, H., Kohl, M., Liyanage, A., Luo, W., Maeda, K., Margaryan, A., Markowitz, P., Maruta, T., Matsumura, A., Maxwell, V., Meekins, D., Mkrtchyan, A., Mkrtchyan, H., Nagao, S., Nakamura, S.N., Narayan, A., Neville, C., Niculescu, G., Niculescu, M.I., Nunez, A., Nuruzzaman, Okayasu, Y., Petković, Tomislav, Pochodzalla, J., Qiu, X., Reinhold, J., Rodriguez, V.M., Samanta, C., Sawatzky, B., Ševa, Tomislav, Shichijo, A., Tadevosyan, V., Tang, L., Taniya, N., Tsukada, K., Veilleux, M., Vulcan, W., Wesselmann, F.R., Wood, S.A., Yamamoto, T., Ya, L., Ye, Z., Yokota, K., Yuan, L., Zhamkochyan, S., and Zhu, L.
- Subjects
spectroscopy ,hyperlithium ,electroproduction ,hypernucleus - Abstract
Missing mass spectroscopy with the (e, e K+) reaction was performed at Jefferson Laboratory’s Hall C for the neutron-rich hypernucleus 9 Li. The ground-state (g.s.) energy was obtained to be Bg.s. = 8.84 ± 0.17stat. ± 0.15sys. MeV by using shell-model calculations of a cross-section ratio and an energy separation of the spin doublet states (3/21+ and 5/21+). In addition, peaks that are considered to be states of [8Li(3+) ⊗ s = 3/22+, 1/2+] and [8Li(1+ ) ⊗ s = 5/22+, 7/2+] were observed at E (no. 2) = 1.74 ± 0.27stat. ± 0.11sys. and E (no. 3) = 3.30 ± 0.24stat. ± 0.11sys. MeV, respectively. The E (no. 3) is larger than shell-model predictions by a few hundred keV, and the difference would indicate that a 5He + t structure is more developed for the 3+ state than those for the 2+ and 1+ states in a core nucleus 8Li as a cluster model calculation suggests
- Published
- 2021
45. The Strong Three-body Weak Interaction Contribution in the Nonmesonic Weak Decay of p-shell Λ Hypernuclei
- Author
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Bhang, H., Ajimura, S., Aoki, K., Banu, A., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E., Kim, J. H., Kim, M., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tshoo, K., Tsukada, K., Watanabe, T., and Yim, H. J.
- Published
- 2013
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46. Three-Body ΛNN → nNN Nonmesonic Weak Decay Process of Λ Hypernuclei
- Author
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Bhang, H., Ajimura, S., Aoki, K., Banu, A., Fukuda, T., Hashimoto, O., Hwang, J. I., Kameoka, S., Kang, B. H., Kim, E., Kim, J. H., Kim, M., Maruta, T., Miura, Y., Miyake, Y., Nagae, T., Nakamura, M., Nakamura, S. N., Noumi, H., Okada, S., Okayasu, Y., Outa, H., Park, H., Saha, P. K., Sato, Y., Sekimoto, M., Takahashi, T., Tamura, H., Tanida, K., Toyoda, A., Tshoo, K., Tsukada, K., Watanabe, T., and Yim, H. J.
- Published
- 2013
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47. Hypernuclear spectroscopy program at JLab Hall C
- Author
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Hashimoto, O., Nakamura, S.N., Acha, A., Ahmidouch, A., Androic, D., Asaturyan, A., Asaturyan, R., Baker, O.K., Baturin, P., Benmokhtar, F., Bosted, P., Carlini, R., Chen, X., Christy, M., Cole, L., Danagoulian, S., Daniel, A., Dharmawardane, V., Egiyan, K., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gan, L., Gaskell, D., Gasparian, A., Gibson, E.F., Gueye, P., Halkyard, R., Honda, D., Horn, T., Hu, B., Hu, S., Hungerford, Ed V., Ispiryan, M., Johnston, K., Jones, M., Kalantarians, N., Kaneta, M., Kato, F., Kato, S., Kawama, D., Keppel, C., Li, Y., Luo, W., Mack, D., Margaryan, A., Marikyan, G., Maruyama, N., Matsumura, A., Miyoshi, T., Mkrtchyan, A., Mkrtchyan, H., Navasardyan, T., Niculescu, G., Niculescu, M.-I., Nomura, H., Nonaka, K., Ohtani, A., Okayasu, Y., Pamela, P., Perez, N., Petkovic, T., Randeniya, S., Reinhold, J., Rivera, R., Roche, J., Rodriguez, V.M., Sato, Y., Seva, T., Tang, L., Simicevic, N., Smith, G., Sumihama, M., Song, Y., Tadevosyan, V., Takahashi, T., Tamura, H., Tvaskis, V., Vulcan, W., Wang, B., Wells, S., Wood, S., Yan, C., Yuan, L., and Zamkochian, S.
- Published
- 2008
- Full Text
- View/download PDF
48. Kaon, pion, and proton associated photofission of Bi nuclei
- Author
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Song, Y., Margaryan, A., Acha, A., Ahmidouch, A., Androic, D., Asaturyan, A., Asaturyan, R., Baker, O. K., Baturin, P., Benmokhtar, F., Carlini, R., Chen, X., Christy, M., Cole, L., Danagoulian, S., Daniel, A., Dharmawardane, V., Egiyan, K., Elaasar, M., Ent, R., Fenker, H., Fujii, Y., Furic, M., Gan, L., Gaskell, D., Gasparian, A., Gibson, E. F., Grigoryan, N., Gueye, P., Halkyard, R., Hashimoto, O., Honda, D., Horn, T., Hu, B., Hu, S., Hungerford, Ed. V., Ispiryan, M., Johnston, K., Jones, M., Kalantarians, N., Kaneta, M., Kato, F., Kato, S., Kawama, D., Keppel, C., Knyazyan, S., Li, Y., Luo, W., Mack, D., Marikyan, G., Maruyama, N., Matsumura, A., Miyoshi, T., Mkrtchyan, A., Mkrtchyan, H., Nakamura, S. N., Navasardyan, T., Niculescu, G., Niculescu, M. -I., Nomura, H., Nonaka, K., Ohtani, A., Okayasu, Y., Pamela, P., Parlakyan, L., Perez, N., Petkovic, T., Randeniya, S., Reinhold, J., Rivera, R., Roche, J., Rodriguez, V. M., Sato, Y., Seva, T., Simicevic, N., Smith, G., Sumihama, M., Tadevosyan, V., Takahashi, T., Tamura, H., Tang, L., Tvaskis, V., Vardanyan, H., Vulcan, W., Wang, B., Wells, S., Wood, S., Yan, C., and Yuan, L.
- Published
- 2010
- Full Text
- View/download PDF
49. Observation of the 7 MeV excited spin-flip and non-spin-flip partners in 16 ΛO by γ -ray spectroscopy
- Author
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Ukai, M., Ajimura, S., Akikawa, H., Alburger, D. E., Banu, A., Chrien, R. E., Franklin, G. B., Franz, J., Hashimoto, O., Hayakawa, T., Hotchi, H., Imai, K., Kishimoto, T., May, M., Millener, D. J., Minami, S., Miura, Y., Miyoshi, T., Mizunuma, K., Nagae, T., Nakamura, S. N., Nakazawa, K., Okayasu, Y., Pile, P., Quinn, B. P., Rusek, A., Sato, Y., Sutter, R., Takahashi, H., Tang, L., Tamura, H., Tanida, K., Yuan, L., and Zhou, S. H.
- Published
- 2007
- Full Text
- View/download PDF
50. An interpretation of SPring-8 ground elevation by the empirical AT L-law approach
- Author
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Okayasu, Y., Matsui, S., Zhang, C., and Kimura, Hiroaki
- Abstract
Starting in 1996, the coordinates of the accelerator components on the SPring-8 storage ring were continuously surveyed for over two decades. The dispersion of the elevation changes of the ground motion lang dz2rang analyzed from the aspect of the empirical ATL-law which has been intensively researched since 1990s. With the ATL-law, lang dz2rang can be expressed as products of a ground diffusion coefficient A, temporal survey spans T, and spatial scales L. The coefficient A is well known to depend on the local geology and is evaluated as (7.6 ± 1.4) × 10−6 μm2/s/m for the SPring-8 storage ring. In this paper, a transition of survey methods in the SPring-8 storage ring is reviewd and survey results both in horizontal and vertical directions are presented. Furthermore, the relevance of the ATL-law approach for the ground elevation dispersion are discussed.
- Published
- 2020
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