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1. First Measurement of $a^0_2(1320)$ Polarized Photoproduction Cross Section

Author

GlueX Collaboration, Afzal, F., Akondi, C. S., Albrecht, M., Amaryan, M., Arrigo, S., Arroyave, V., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Barton, D., Baturin, V., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Cao, S., Chudakov, E., Chung, G., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Darulis, D., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Dzhygadlo, R., Ebersole, D., Edo, M., Egiyan, H., Erbora, T., Eugenio, P., Fabrizi, A., Fanelli, C., Fang, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gardner, A., Gasparian, A., Glazier, D. I., Gleason, C., Goryachev, V. S., Grube, B., Guo, J., Guo, L., Hernandez, J., Hernandez, K., Hoffman, N. D., Hornidge, D., Hou, G., Hurck, P., Hurley, A., Imoehl, W., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jeske, T., Jing, M., Jones, R. T., Kakoyan, V., Kalicy, G., Khachatryan, V., Kourkoumelis, C., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Lyubovitskij, V., Ma, R., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Moran, P., Neelamana, V., Ng, L., Nissen, E., Orešić, S., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pedroni, R., Pentchev, L., Peters, K. J., Prather, E., Veetil, L. Puthiya, Rakshit, S., Reinhold, J., Remington, A., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Scheuer, K., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Scott, M., Septian, N., Sharp, P., Shen, X., Shepherd, M. R., Sikes, J., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Wunderlich, Y., Yu, B., Zarling, J., Zhang, Z., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We measure for the first time the differential photoproduction cross section $d\sigma/dt$ of the $a_2(1320)$ meson at an average photon beam energy of 8.5~GeV, using data with an integrated luminosity of 104~pb$^{-1}$ collected by the GlueX experiment. We fully reconstruct the $\gamma p \to \eta\pi^0 p$ reaction and perform a partial-wave analysis in the $a_2(1320)$ mass region with amplitudes that incorporate the linear polarization of the beam. This allows us to separate for the first time the contributions of natural- and unnatural-parity exchanges. These measurements provide novel information about the photoproduction mechanism, which is critical for the search for spin-exotic states., Comment: 8 pages, 4 figures plus supplemental material

Published
2025

2. Upper Limit on the Photoproduction Cross Section of the Spin-Exotic $\pi_1(1600)$

Author

GlueX Collaboration, Afzal, F., Akondi, C. S., Albrecht, M., Amaryan, M., Arrigo, S., Arroyave, V., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Barton, D., Baturin, V., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Cao, S., Chudakov, E., Chung, G., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Darulis, D., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Dzhygadlo, R., Ebersole, D., Edo, M., Egiyan, H., Erbora, T., Eugenio, P., Fabrizi, A., Fanelli, C., Fang, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gardner, A., Gasparian, A., Glazier, D., Gleason, C., Goryachev, V. S., Grube, B., Guo, J., Guo, L., Hernandez, J., Hernandez, K., Hoffman, N. D., Hornidge, D., Hou, G., Hurck, P., Hurley, A., Imoehl, W., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jeske, T., Jing, M., Jones, R. T., Kakoyan, V., Kalicy, G., Khachatryan, V., Kourkoumelis, C., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Lyubovitskij, V., Ma, R., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Ng, L., Nissen, E., Orešić, S., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pedroni, R., Pentchev, L., Peters, K. J., Prather, E., Rakshit, S., Reinhold, J., Remington, A., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Scheuer, K., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Septian, N., Sharp, P., Shen, X., Shepherd, M. R., Sikes, J., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Wunderlich, Y., Yu, B., Zarling, J., Zhang, Z., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The spin-exotic hybrid meson $\pi_{1}(1600)$ is predicted to have a large decay rate to the $\omega\pi\pi$ final state. Using 76.6~pb$^{-1}$ of data collected with the GlueX detector, we measure the cross sections for the reactions $\gamma p \to \omega \pi^+ \pi^- p$, $\gamma p \to \omega \pi^0 \pi^0 p$, and $\gamma p\to\omega\pi^-\pi^0\Delta^{++}$ in the range $E_\gamma =$ 8-10 GeV. Using isospin conservation, we set the first upper limits on the photoproduction cross sections of the $\pi^{0}_{1}(1600)$ and $\pi^{-}_{1}(1600)$. We combine these limits with lattice calculations of decay widths and find that photoproduction of $\eta'\pi$ is the most sensitive two-body system to search for the $\pi_1(1600)$., Comment: 7 pages, 3 figures plus supplemental materials

Published
2024
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3. Measurement of Spin-Density Matrix Elements in $\rho(770)$ Production with a Linearly Polarized Photon Beam at $E_\gamma = 8.2\,-\,8.8\,\text{GeV}$

Author

GlueX Collaboration, Adhikari, S., Afzal, F., Akondi, C. S., Albrecht, M., Amaryan, M., Arroyave, V., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Byer, D., Chudakov, E., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Darulis, D., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Edo, M., Egiyan, H., Erbora, T., Eugenio, P., Fabrizi, A., Fanelli, C., Fang, S., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gardner, A., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Grube, B., Guo, J., Guo, L., Hague, T. J., Hakobyan, H., Hernandez, J., Hoffman, N. D., Hornidge, D., Hou, G., Huber, G. M., Hurck, P., Hurley, A., Imoehl, W., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jeske, T., Jones, R. T., Kakoyan, V., Kalicy, G., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Lyubovitskij, V., Ma, R., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Ng, L., Nissen, E., Orešić, S., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pedroni, R., Pentchev, L., Peters, K. J., Prather, E., Rakshit, S., Reinhold, J., Remington, A., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Scheuer, K., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Wunderlich, Y., Yu, B., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The GlueX experiment at Jefferson Lab studies photoproduction of mesons using linearly polarized $8.5\,\text{GeV}$ photons impinging on a hydrogen target which is contained within a detector with near-complete coverage for charged and neutral particles. We present measurements of spin-density matrix elements for the photoproduction of the vector meson $\rho$(770). The statistical precision achieved exceeds that of previous experiments for polarized photoproduction in this energy range by orders of magnitude. We confirm a high degree of $s$-channel helicity conservation at small squared four-momentum transfer $t$ and are able to extract the $t$-dependence of natural and unnatural-parity exchange contributions to the production process in detail. We confirm the dominance of natural-parity exchange over the full $t$ range. We also find that helicity amplitudes in which the helicity of the incident photon and the photoproduced $\rho(770)$ differ by two units are negligible for $-t<0.5\,\text{GeV}^{2}/c^{2}$., Comment: 15 pages, 11 figures

Published
2023
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4. Measurement of the J/$\psi $ photoproduction cross section over the full near-threshold kinematic region

Author

GlueX Collaboration, Adhikari, S., Afzal, F., Akondi, C. S., Albrecht, M., Amaryan, M., Arroyave, V., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Byer, D., Chudakov, E., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Darulis, D., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Egiyan, H., Erbora, T., Eugenio, P., Fabrizi, A., Fanelli, C., Fang, S., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gardner, A., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Grube, B., Guo, J., Guo, L., Hague, T. J., Hakobyan, H., Hernandez, J., Hoffman, N. D., Hornidge, D., Hou, G., Huber, G. M., Hurck, P., Hurley, A., Imoehl, W., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jeske, T., Jones, R. T., Kakoyan, V., Kalicy, G., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Lyubovitskij, V., Mack, D., Mahmood, A., Martel, P. P., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Ng, L., Nissen, E., Orei, S., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pedroni, R., Pentchev, L., Peters, K. J., Prather, E., Rakshit, S., Reinhold, J., Remington, A., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Scheuer, K., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, S., Somov, A., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Wunderlich, Y., Yu, B., Zarling, J., Zhang, Z., Zhao, Z., Zhou, X., Zhou, J., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report the total and differential cross sections for $J/\psi$ photoproduction with the large acceptance GlueX spectrometer for photon beam energies from the threshold at 8.2~GeV up to 11.44~GeV and over the full kinematic range of momentum transfer squared, $t$. Such coverage facilitates the extrapolation of the differential cross sections to the forward ($t = 0$) point beyond the physical region. The forward cross section is used by many theoretical models and plays an important role in understanding $J/\psi$ photoproduction and its relation to the $J/\psi-$proton interaction. These measurements of $J/\psi$ photoproduction near threshold are also crucial inputs to theoretical models that are used to study important aspects of the gluon structure of the proton, such as the gluon Generalized Parton Distribution (GPD) of the proton, the mass radius of the proton, and the trace anomaly contribution to the proton mass. We observe possible structures in the total cross section energy dependence and find evidence for contributions beyond gluon exchange in the differential cross section close to threshold, both of which are consistent with contributions from open-charm intermediate states., Comment: 15 pages 18 figures

Published
2023
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5. Search for photoproduction of axion-like particles at GlueX

Author

GlueX Collaboration, Adhikari, S., Akondi, C. S., Albrecht, M., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Chudakov, E., Cole, S., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hagen, M., Hakobyan, H., Hamdi, A., Hernandez, J., Hoffman, N. D., Hou, G., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Luckas, K., Lyubovitskij, V., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Yoon, S., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, X., and Zihlmann, B.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We present a search for axion-like particles, $a$, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the $a$-gluon coupling is dominant. The search uses $a\to\gamma\gamma$ and $a\to\pi^+\pi^-\pi^0$ decays, and a data sample corresponding to an integrated luminosity of 168 pb$^{-1}$ collected with the GlueX detector. The search for $a\to\gamma\gamma$ decays is performed in the mass range of $180 < m_a < 480$ MeV, while the search for $a\to\pi^+\pi^-\pi^0$ decays explores the $600 < m_a < 720$ MeV region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the $a$-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered., Comment: 8 pages, 4 figures, 2 tables; updated to published version

Published
2021
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6. Measurement of Spin Density Matrix Elements in $\Lambda(1520)$ Photoproduction at 8.2-8.8 GeV

Author

GlueX Collaboration, Adhikari, S., Akondi, C. S., Albrecht, M., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Chudakov, E., Cole, S., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hagen, M., Hakobyan, H., Hamdi, A., Hernandez, J., Hoffman, N. D., Hou, G., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Luckas, K., Lyubovitskij, V., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, X., Zhou, Q., Zihlmann, B., Glazier, D. I., and Mathieu, V.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report on the measurement of spin density matrix elements of the $\Lambda(1520)$ in the photoproduction reaction $\gamma p\rightarrow \Lambda(1520)K^+$, via its subsequent decay to $K^{-}p$. The measurement was performed as part of the GlueX experimental program in Hall D at Jefferson Lab using a linearly polarized photon beam with $E_\gamma =$ 8.2-8.8 GeV. These are the first such measurements in this photon energy range. Results are presented in bins of momentum transfer squared, $-(t-t_\text{0})$. We compare the results with a Reggeon exchange model and determine that natural exchange amplitudes are dominant in $\Lambda(1520)$ photoproduction., Comment: 11 pages, 8 figures, accepted version

Published
2021
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7. Measurement of beam asymmetry for $\pi^-\Delta^{++}$ photoproduction on the proton at $E_\gamma$=8.5 GeV

Author

GlueX Collaboration, Adhikari, S., Akondi, C. S., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Luckas, K., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schumacher, R. A., Schwiening, J., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, Q., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report a measurement of the $\pi^-$ photoproduction beam asymmetry for the reaction $\vec{\gamma} p \rightarrow \pi^- \Delta^{++}$ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry $\Sigma$ is measured as a function of four-momentum transfer $t$ to the $\Delta^{++}$ and compared to phenomenological models. We find that $\Sigma$ varies as a function of $t$: negative at smaller values and positive at higher values of $|t|$. The reaction can be described theoretically by $t$-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy., Comment: 7 pages, 5 figures

Published
2020
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8. Measurement of the Photon Beam Asymmetry in $\vec{\gamma} p\to K^+\Sigma^0$ at $E_{\gamma} = 8.5$ GeV

Author

The GlueX Collaboration, Adhikari, S., Ali, A., Amaryan, M., Austregesilo, A., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Nerling, F., Ng, L., Ni, H., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhou, Q., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

We report measurements of the photon beam asymmetry $\Sigma$ for the reaction $\vec{\gamma} p\to K^+\Sigma^0$(1193) using the GlueX spectrometer in Hall D at Jefferson Lab. Data were collected using a linearly polarized photon beam in the energy range of 8.2-8.8 GeV incident on a liquid hydrogen target. The beam asymmetry $\Sigma$ was measured as a function of the Mandelstam variable $t$, and a single value of $\Sigma$ was extracted for events produced in the $u$-channel. These are the first exclusive measurements of the photon beam asymmetry $\Sigma$ for the reaction in this energy range. For the $t$-channel, the measured beam asymmetry is close to unity over the $t$-range studied, $-t=(0.1-1.4)~$(GeV/$c$)$^{2}$, with an average value of $\Sigma = 1.00\pm 0.05$. This agrees with theoretical models that describe the reaction via the natural-parity exchange of the $K^{*}$(892) Regge trajectory. A value of $\Sigma = 0.41 \pm 0.09$ is obtained for the $u$-channel integrated up to $-u=2.0$~(GeV/$c$)$^{2}$.

Published
2020
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9. Beam Asymmetry $\mathbf{\Sigma}$ for the Photoproduction of $\mathbf{\eta}$ and $\mathbf{\eta^{\prime}}$ Mesons at $\mathbf{E_{\gamma}=8.8}$GeV

Author

The GlueX Collaboration, Adhikari, S., Ali, A., Amaryan, M., Austregesilo, A., Barbosa, F., Barlow, J., Barnes, A., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gevorgyan, N., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Mattione, P., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Semenov, A. Yu., Semenova, I. A., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Staib, M., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhao, G., Zhou, Q., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report on the measurement of the beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\rightarrow p\eta$ and $\vec{\gamma}p \rightarrow p\eta^{\prime}$ from the GlueX experiment, using an 8.2--8.8 GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Lab. These measurements are made as a function of momentum transfer $-t$, with significantly higher statistical precision than our earlier $\eta$ measurements, and are the first measurements of $\eta^{\prime}$ in this energy range. We compare the results to theoretical predictions based on $t$--channel quasi-particle exchange. We also compare the ratio of $\Sigma_{\eta}$ to $\Sigma_{\eta^{\prime}}$ to these models, as this ratio is predicted to be sensitive to the amount of $s\bar{s}$ exchange in the production. We find that photoproduction of both $\eta$ and $\eta^{\prime}$ is dominated by natural parity exchange with little dependence on $-t$., Comment: 18 pages, 7 figures

Published
2019
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10. First measurement of near-threshold J/$\psi $ exclusive photoproduction off the proton

Author

The GlueX Collaboration, Ali, A., Amaryan, M., Anassontzis, E. G., Austregesilo, A., Baalouch, M., Barbosa, F., Barlow, J., Barnes, A., Barriga, E., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gauzshtein, V., Gevorgyan, N., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Han, S., Hardin, J., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Kuznetsov, I., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Werthmueller, D., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhao, G., Zhou, Q., Zhou, X., and Zihlmann, B.

Subjects
Nuclear Experiment
Abstract

We report on the measurement of the $\gamma p \rightarrow J/\psi p$ cross section from $E_\gamma = 11.8$ GeV down to the threshold at $8.2$ GeV using a tagged photon beam with the GlueX experiment. We find the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section $d\sigma /dt$ has an exponential slope of $1.67 \pm 0.39$ GeV$^{-2}$ at $10.7$ GeV average energy. The LHCb pentaquark candidates $P_c^+$ can be produced in the $s$-channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions $\mathcal{B}(P_c^+ \rightarrow J/\psi p)$ and cross sections $\sigma(\gamma p \to P_c^+)\times\mathcal{B}(P_c^+ \to J/\psi p) $., Comment: 12 pages, 7 figures

Published
2019
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11. Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ and $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV

Author

GlueX Collaboration, Ghoul, H. Al, Anassontzis, E. G., Austregesilo, A., Barbosa, F., Barnes, A., Beattie, T. D., Bennett, D. W., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Brooks, W. K., Cannon, B. E., Chernyshov, O., Chudakov, E., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Dzhygadlo, R., Egiyan, H., Eugenio, P., Fanelli, C., Foda, A. M., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gerasimov, A., Gevorgyan, N., Goetzen, K., Goryachev, V. S., Guo, L., Hakobyan, H., Hardin, J., Henderson, A., Huber, G. M., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kamel, M., Klein, F. J., Kliemt, R., Kourkoumeli, C., Kuleshov, S., Kuznetsov, I., Lara, M., Larin, I., Lawrence, D., Levine, W. I., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Mattione, P. T., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Mendez, R., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Moriya, K., Nerling, F., Nigmatkulov, G., Ochoa, N., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pedroni, R., Pennington, M. R., Pentchev, L., Peters, K. J., Pooser, E., Pratt, B., Qiang, Y., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Salgado, C., Schumacher, R. A., Schwarz, C., Schwiening, J., Semenov, A. Yu., Semenova, I. A., Seth, K. K., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Sparks, N., Staib, M. J., Stevens, J. R., Strakovsky, I. I., Subedi, A., Tarasov, V., Taylor, S., Teymurazyan, A., Tolstukhin, I., Tomaradze, A., Toro, A., Tsaris, A., Vasileiadis, G., Vega, I., Walford, N. K., Werthmuller, D., Whitlatch, T., Williams, M., Wolin, E., Xiao, T., Zarling, J., Zhang, Z., Zihlmann, B., Mathieu, V., and Nys, J.

Subjects
Nuclear Experiment
Abstract

We report measurements of the photon beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\to p\pi^0$ and $\vec{\gamma}p\to p\eta $ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $\pi^0$ measurements and are the first $\eta$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models., Comment: 6 pages, 6 figures, Published in Physical Review C: Rapid Communication

Published
2017
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12. First Results from The GlueX Experiment

Author

The GlueX Collaboration, Ghoul, H. Al, Anassontzis, E. G., Barbosa, F., Barnes, A., Beattie, T. D., Bennett, D. W., Berdnikov, V. V., Black, T., Boeglin, W., Brooks, W. K., Cannon, B., Chernyshov, O., Chudakov, E., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Egiyan, H., Eugenio, P., Foda, A. M., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gerasimov, A., Gevorgyan, N., Goryachev, V. S., Guegan, B., Guo, L., Hakobyan, H., Hakobyan2, H., Hardin, J., Huber, G. M., Ireland, D., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kamel, M., Klein, F. J., Kourkoumeli, C., Kuleshov, S., Lara, M., Larin, I., Lawrence, D., Leckey, J., Levine, W. I., Livingston, K., Lolos, G. J., Mack, D., Mattione, P. T., Matveev, V., McCaughan, M., McGinley, W., McIntyre, J., Mendez, R., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Moriya, K., Nigmatkulov, G., Ochoa, N., Ostrovidov, A. I., Papandreou, Z., Pedroni, R., Pennington, M., Pentchev, L., Ponosov, A., Pooser, E., Pratt, B., Qiang, Y., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Salgado, C., Schumacher, R. A., Semenov, A. Yu., Semenova, I. A., Senderovich, I., Seth, K. K., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Sparks, N., Staib, M. J., Stevens, J. R., Subedi, A., Tarasov, V., Taylor, S., Tolstukhin, I., Tomaradze, A., Toro, A., Tsaris, A., Vasileiadis, G., Vega, I., Voulgaris, G., Walford, N. K., Whitlatch, T., Williams, M., Wolin, E., Xiao, T., Zarling, J., and Zihlmann, B.

Subjects
Nuclear Experiment, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract

The GlueX experiment at Jefferson Lab ran with its first commissioning beam in late 2014 and the spring of 2015. Data were collected on both plastic and liquid hydrogen targets, and much of the detector has been commissioned. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed, including exclusive production of $\pi^{0}$, $\eta$ and $\omega$ mesons. Linearly-polarized photons were successfully produced through coherent bremsstrahlung and polarization transfer to the $\rho$ has been observed., Comment: 8 pages, 6 figures, Invited contribution to the Hadron 2015 Conference, Newport News VA, September 2015

Published
2015
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13. A study of decays to strange final states with GlueX in Hall D using components of the BaBar DIRC

Author

The GlueX Collaboration, Dugger, M., Ritchie, B., Senderovich, I., Anassontzis, E., Ioannou, P., Kourkoumeli, C., Vasileiadis, G., Voulgaris, G., Jarvis, N., Levine, W., Mattione, P., McGinley, W., Meyer, C. A., Schumacher, R., Staib, M., Klein, F., Sober, D., Sparks, N., Walford, N., Doughty, D., Barnes, A., Jones, R., McIntyre, J., Mokaya, F., Pratt, B., Boeglin, W., Guo, L., Pooser, E., Reinhold, J., Ghoul, H. Al, Crede, V., Eugenio, P., Ostrovidov, A., Tsaris, A., Ireland, D., Livingston, K., Bennett, D., Bennett, J., Frye, J., Lara, M., Leckey, J., Mitchell, R., Moriya, K., Shepherd, M. R., Chernyshov, O., Dolgolenko, A., Gerasimov, A., Goryachev, V., Larin, I., Matveev, V., Tarasov, V., Barbosa, F., Chudakov, E., Dalton, M., Deur, A., Dudek, J., Egiyan, H., Furletov, S., Ito, M., Mack, D., Lawrence, D., McCaughan, M., Pennington, M., Pentchev, L., Qiang, Y., Smith, E., Somov, A., Taylor, S., Whitlatch, T., Zihlmann, B., Miskimen, R., Guegan, B., Hardin, J., Stevens, J., Williams, M., Berdnikov, V., Nigmatkulov, G., Ponosov, A., Romanov, D., Somov, S., Tolstukhin, I., Salgado, C., Ambrozewicz, P., Gasparian, A., Pedroni, R., Black, T., Gan, L., Dobbs, S., Seth, K., Ting, X., Tomaradze, A., Beattie, T., Huber, G., Lolos, G., Papandreou, Z., Semenov, A., Semenova, I., Brooks, W., Hakobyan, H., Kuleshov, S., Soto, O., Toro, A., Vega, I., Gevorgyan, N., and Kakoyan, V.

Subjects
Physics - Instrumentation and Detectors, High Energy Physics - Experiment
Abstract

We propose to enhance the kaon identification capabilities of the GlueX detector by constructing an FDIRC (Focusing Detection of Internally Reflected Cherenkov) detector utilizing the decommissioned BaBar DIRC components. The GlueX FDIRC would significantly enhance the GlueX physics program by allowing one to search for and study hybrid mesons decaying into kaon final states. Such systematic studies of kaon final states are essential for inferring the quark flavor content of hybrid and conventional mesons. The GlueX FDIRC would reuse one-third of the synthetic fused silica bars that were utilized in the BaBar DIRC. A new focussing photon camera, read out with large area photodetectors, would be developed. We propose operating the enhanced GlueX detector in Hall D for a total of 220 days at an average intensity of 5x10^7 {\gamma}/s, a program that was conditionally approved by PAC39, Comment: 25 pages, 29 figures

Published
2014

14. An initial study of mesons and baryons containing strange quarks with GlueX

Author

The GlueX Collaboration, AlekSejevs, A., Barkanova, S., Dugger, M., Ritchie, B., Senderovich, I., Anassontzis, E., Ioannou, P., Kourkoumeli, C., Voulgaris, G., Jarvis, N., Levine, W., Mattione, P., McGinley, W., Meyer, C. A., Schumacher, R., Staib, M., Collins, P., Klein, F., Sober, D., Doughty, D., Barnes, A., Jones, R., McIntyre, J., Mokaya, F., Pratt, B., Boeglin, W., Guo, L., Khetarpal, P., Pooser, E., Reinhold, J., Ghoul, H. Al, Capstick, S., Crede, V., Eugenio, P., Ostrovidov, A., Sparks, N., Tsaris, A., Ireland, D., Livingston, K., Bennett, D., Bennett, J., Frye, J., Lara, M., Leckey, J., Mitchell, R., Moriya, K., Shepherd, M. R., Szczepaniak, A., Miskimen, R., Mushkarenkov, A., Guegan, B., Hardin, J., Stevens, J., Williams, M., Ponosov, A., Somov, S., Salgado, C., Ambrozewicz, P., Gasparian, A., Pedroni, R., Black, T., Gan, L., Dobbs, S., Seth, K. K., Tomaradze, A., Dudek, J., Close, F., Swanson, E., Denisov, S., Huber, G., Kolybaba, D., Krueger, S., Lolos, G., Papandreou, Z., Semenov, A., Semenova, I., Tahani, M., Brooks, W., Hakobyan, H., Kuleshov, S., Soto, O., Toro, A., Vega, I., White, R., Barbosa, F., Chudakov, E., Egiyan, H., Ito, M., Lawrence, D., McCaughan, M., Pennington, M., Pentchev, L., Qiang, Y., Smith, E. S., Somov, A., Taylor, S., Whitlatch, T., Wolin, E., and Zihlmann, B.

Subjects
Nuclear Experiment
Abstract

The primary motivation of the GlueX experiment is to search for and ultimately study the pattern of gluonic excitations in the meson spectrum produced in $\gamma p$ collisions. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons that have both exotic and non-exotic $J^{PC}$, corresponding to $q\bar{q}$ states ($q=u,$ $d,$ or $s$) coupled with a gluonic field. A thorough study of the hybrid spectrum, including the identification of the isovector triplet, with charges 0 and $\pm1$, and both isoscalar members, $|s\bar{s}\ >$ and $|u\bar{u}\ > + |d\bar{d}\ >$, for each predicted hybrid combination of $J^{PC}$, may only be achieved by conducting a systematic amplitude analysis of many different hadronic final states. Detailed studies of the performance of the \gx detector have indicated that identification of particular final states with kaons is possible using the baseline detector configuration. The efficiency of kaon detection coupled with the relatively lower production cross section for particles containing hidden strangeness will require a high intensity run in order for analyses of such states to be feasible. We propose to collect a total of 200 days of physics analysis data at an average intensity of $5\times 10^7$ tagged photons on target per second. This data sample will provide an order of magnitude statistical improvement over the initial GlueX running, which will allow us to begin a program of studying mesons and baryons containing strange quarks. In addition, the increased intensity will permit us to study reactions that may have been statistically limited in the initial phases of GlueX. Overall, this will lead to a significant increase in the potential for \gx to make key experimental advances in our knowledge of hybrid mesons and excited $\Xi$ baryons., Comment: 22 pages, 8 figures

Published
2013

15. A study of meson and baryon decays to strange final states with GlueX in Hall D (A proposal to the 39th Jefferson Lab Program Advisory Committee)

Author

The GlueX Collaboration, Dugger, M., Ritchie, B., Anassontzis, E., Ioannou, P., Kourkoumeli, C., Voulgaris, G., Jarvis, N., Levine, W., Mattione, P., Meyer, C. A., Schumacher, R., Collins, P., Klein, F., Sober, D., Doughty, D., Barnes, A., Jones, R., McIntyre, J., Mokaya, F., Pratt, B., Senderovich, I., Boeglin, W., Guo, L., Khetarpal, P., Pooser, E., Reinhold, J., Ghoul, H. Al, Capstick, S., Crede, V., Eugenio, P., Ostrovidov, A., Sparks, N., Tsaris, A., Ireland, D., Livingston, K., Bennett, D., Bennett, J., Frye, J., Leckey, J., Mitchell, R., Moriya, K., Shepherd, M. R., Szczepaniak, A., Miskimen, R., Williams, M., Ambrozewicz, P., Gasparian, A., Pedroni, R., Black, T., Gan, L., Dudek, J., Close, F., Swanson, E., Denisov, S., Huber, G., Katsaganis, S., Kolybaba, D., Lolos, G., Papandreou, Z., Semenov, A., Semenova, I., Tahani, M., Brooks, W., Kuleshov, S., Toro, A., Barbosa, F., Chudakov, E., Egiyan, H., Ito, M., Lawrence, D., Pentchev, L., Qiang, Y., Smith, E. S., Somov, A., Taylor, S., Whitlatch, T., Wolin, E., and Zihlmann, B.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

The primary motivation of the GlueX experiment is to search for and ultimately study the pattern of gluonic excitations in the meson spectrum produced in gamma p collisions. Recent lattice QCD calculations predict a rich spectrum of hybrid mesons that have both exotic and non-exotic JPC, corresponding to q q-bar (q=u, d, or s) states coupled with a gluonic field. A thorough study of the hybrid spectrum, including the identification of the isovector triplet, with charges 0 and +-1, and both isoscalar members, |s s-bar> and |u u-bar> + |d d-bar>, for each predicted hybrid combination of JPC, may only be achieved by conducting a systematic amplitude analysis of many different hadronic final states. We propose the development of a kaon identification system, supplementing the existing GlueX forward time-of-flight detector, in order to cleanly select meson and baryon decay channels that include kaons. Once this detector has been installed and commissioned, we plan to collect a total of 200 days of physics analysis data at an average intensity of 5 x 10^7 tagged photons on target per second. This data sample will provide an order of magnitude statistical improvement over the initial GlueX data set and, with the developed kaon identification system, a significant increase in the potential for GlueX to make key experimental advances in our knowledge of hybrid mesons and Cascade baryons., Comment: 20 pages, 9 figures (submitted to the 39th Jefferson Lab PAC)

Published
2012

16. Search for photoproduction of axionlike particles at GlueX

Author

GlueX Collaboration, Adhikari, S., Akondi, C. S., Albrecht, M., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Chudakov, E., Cole, S., Cole, P. L., Cortes, O., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Ebersole, D., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hagen, M., Hakobyan, H., Hamdi, A., Hernandez, J., Hoffman, N. D., Hou, G., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Lorenti, L., Luckas, K., Lyubovitskij, V., Mack, D., Mahmood, A., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Saldana, K., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schmidt, A., Schumacher, R. A., Schwiening, J., Sharp, P., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Viducic, T., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Yoon, S., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, X., and Zihlmann, B.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, фотоны, FOS: Physical sciences, глюоны, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), ddc:530, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment, протон-протонные столкновения, аксионоподобные частицы
Abstract

We present a search for axion-like particles, $a$, produced in photon-proton collisions at a center-of-mass energy of approximately 4 GeV, focusing on the scenario where the $a$-gluon coupling is dominant. The search uses $a\to\gamma\gamma$ and $a\to\pi^+\pi^-\pi^0$ decays, and a data sample corresponding to an integrated luminosity of 168 pb$^{-1}$ collected with the GlueX detector. The search for $a\to\gamma\gamma$ decays is performed in the mass range of $180 < m_a < 480$ MeV, while the search for $a\to\pi^+\pi^-\pi^0$ decays explores the $600 < m_a < 720$ MeV region. No evidence for a signal is found, and 90% confidence-level exclusion limits are placed on the $a$-gluon coupling strength. These constraints are the most stringent to date over much of the mass ranges considered., Comment: 8 pages, 4 figures, 2 tables; updated to published version

Published
2022
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17. Measurement of beam asymmetry for π- Δ++ photoproduction on the proton at Eγ=8.5 GeV

Author

Adhikari, S. Akondi, C.S. Ali, A. Amaryan, M. Asaturyan, A. Austregesilo, A. Baldwin, Z. Barbosa, F. Barlow, J. Barriga, E. Barsotti, R. Beattie, T.D. Berdnikov, V.V. Black, T. Boeglin, W. Briscoe, W.J. Britton, T. Brooks, W.K. Cannon, B.E. Chudakov, E. Cole, S. Cortes, O. Crede, V. Dalton, M.M. Daniels, T. Deur, A. Dobbs, S. Dolgolenko, A. Dotel, R. Dugger, M. Dzhygadlo, R. Egiyan, H. Erbora, T. Ernst, A. Eugenio, P. Fanelli, C. Fegan, S. Fitches, J. Foda, A.M. Furletov, S. Gan, L. Gao, H. Gasparian, A. Gleason, C. Goetzen, K. Goryachev, V.S. Guo, L. Hakobyan, H. Hamdi, A. Huber, G.M. Hurley, A. Ireland, D.G. Ito, M.M. Jaegle, I. Jarvis, N.S. Jones, R.T. Kakoyan, V. Kalicy, G. Kamel, M. Khachatryan, V. Khatchatryan, M. Kourkoumelis, C. Kuleshov, S. Laduke, A. Larin, I. Lawrence, D. Lersch, D.I. Li, H. Li, W.B. Liu, B. Livingston, K. Lolos, G.J. Luckas, K. Lyubovitskij, V. Mack, D. Marukyan, H. Matveev, V. McCaughan, M. McCracken, M. McGinley, W. Meyer, C.A. Miskimen, R. Mitchell, R.E. Mizutani, K. Neelamana, V. Nerling, F. Ng, L. Ostrovidov, A.I. Papandreou, Z. Paudel, C. Pauli, P. Pedroni, R. Pentchev, L. Peters, K.J. Phelps, W. Pooser, E. Reinhold, J. Ritchie, B.G. Ritman, J. Rodriguez, G. Romanov, D. Romero, C. Salgado, C. Schadmand, S. Schertz, A.M. Schick, A. Schumacher, R.A. Schwiening, J. Shen, X. Shepherd, M.R. Smith, A. Smith, E.S. Sober, D.I. Somov, A. Somov, S. Soto, O. Stevens, J.R. Strakovsky, I.I. Sumner, B. Suresh, K. Tarasov, V.V. Taylor, S. Teymurazyan, A. Thiel, A. Vasileiadis, G. Whitlatch, T. Wickramaarachchi, N. Williams, M. Yang, Y. Zarling, J. Zhang, Z. Zhao, Z. Zhou, J. Zhou, Q. Zhou, X. Zihlmann, B. The GlueX Collaboration

Subjects
High Energy Physics::Experiment, Nuclear Experiment
Abstract

We report a measurement of the π- photoproduction beam asymmetry for the reaction γp→π-Δ++ using data from the GlueX experiment in the photon beam energy range 8.2-8.8 GeV. The asymmetry ς is measured as a function of four-momentum transfer t to the Δ++ and compared to phenomenological models. We find that ς varies as a function of t: negative at smaller values and positive at higher values of |t|. The reaction can be described theoretically by t-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy. © 2021 American Physical Society.

Published
2021

18. Measurement of beam asymmetry for $��^-��^{++}$ photoproduction on the proton at $E_��$=8.5 GeV

Author

GlueX Collaboration, Adhikari, S., Akondi, C. S., Ali, A., Amaryan, M., Asaturyan, A., Austregesilo, A., Baldwin, Z., Barbosa, F., Barlow, J., Barriga, E., Barsotti, R., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Erbora, T., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Fitches, J., Foda, A. M., Furletov, S., Gan, L., Gao, H., Gasparian, A., Gleason, C., Goetzen, K., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jaegle, I., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Khachatryan, V., Khatchatryan, M., Kourkoumelis, C., Kuleshov, S., LaDuke, A., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W. B., Liu, B., Livingston, K., Lolos, G. J., Luckas, K., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mizutani, K., Neelamana, V., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Paudel, C., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Reinhold, J., Ritchie, B. G., Ritman, J., Rodriguez, G., Romanov, D., Romero, C., Salgado, C., Schadmand, S., Schertz, A. M., Schick, A., Schumacher, R. A., Schwiening, J., Shen, X., Shepherd, M. R., Smith, A., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Sumner, B., Suresh, K., Tarasov, V. V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Whitlatch, T., Wickramaarachchi, N., Williams, M., Yang, Y., Zarling, J., Zhang, Z., Zhao, Z., Zhou, J., Zhou, Q., Zhou, X., and Zihlmann, B.

Subjects
High Energy Physics - Experiment (hep-ex), Nuclear Theory, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We report a measurement of the $��^-$ photoproduction beam asymmetry for the reaction $\vec�� p \rightarrow ��^- ��^{++}$ using data from the GlueX experiment in the photon beam energy range 8.2--8.8 GeV. The asymmetry $��$ is measured as a function of four-momentum transfer $t$ to the $��^{++}$ and compared to phenomenological models. We find that $��$ varies as a function of $t$: negative at smaller values and positive at higher values of $|t|$. The reaction can be described theoretically by $t$-channel particle exchange requiring pseudoscalar, vector, and tensor intermediaries. In particular, this reaction requires charge exchange, allowing us to probe pion exchange and the significance of higher-order corrections to one-pion exchange at low momentum transfer. Constraining production mechanisms of conventional mesons may aid in the search for and study of unconventional mesons. This is the first measurement of the process at this energy., 7 pages, 5 figures

Published
2020
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19. First Measurement of Near-Threshold J/ψ Exclusive Photoproduction off the Proton

Author

The GlueX Collaboration, Ali, A., Amaryan, M., Anassontzis, E. G., Austregesilo, A., Baalouch, M., Barbosa, F., Barlow, J., Barnes, A., Barriga, E., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gauzshtein, V., Gevorgyan, N., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Han, S., Hardin, J., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Kuznetsov, I., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Werthmueller, D., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhao, G., Zhou, Q., Zhou, X., and Zihlmann, B.

Subjects
Physics, Scattering cross-section, GlueX, General Physics and Astronomy, Exotic hadron, 01 natural sciences, 7. Clean energy, Pentaquark, Model exchange, Nuclear physics, Near threshold, 0103 physical sciences, High Energy Physics::Experiment, Photon beam, 010306 general physics, Nuclear Experiment
Abstract

We report on the measurement of the $\gamma p \rightarrow J/\psi p$ cross section from $E_\gamma = 11.8$ GeV down to the threshold at $8.2$ GeV using a tagged photon beam with the GlueX experiment. We find the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section $d\sigma /dt$ has an exponential slope of $1.67 \pm 0.39$ GeV$^{-2}$ at $10.7$ GeV average energy. The LHCb pentaquark candidates $P_c^+$ can be produced in the $s$-channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions $\mathcal{B}(P_c^+ \rightarrow J/\psi p)$ and cross sections $\sigma(\gamma p \to P_c^+)\times\mathcal{B}(P_c^+ \to J/\psi p) $., Comment: 12 pages, 7 figures

Published
2019

20. First Measurement of Near-Threshold J /ψ Exclusive Photoproduction off the Proton

Author

Ali, A. Amaryan, M. Anassontzis, E.G. Austregesilo, A. Baalouch, M. Barbosa, F. Barlow, J. Barnes, A. Barriga, E. Beattie, T.D. Berdnikov, V.V. Black, T. Boeglin, W. Boer, M. Briscoe, W.J. Britton, T. Brooks, W.K. Cannon, B.E. Cao, N. Chudakov, E. Cole, S. Cortes, O. Crede, V. Dalton, M.M. Daniels, T. Deur, A. Dobbs, S. Dolgolenko, A. Dotel, R. Dugger, M. Dzhygadlo, R. Egiyan, H. Ernst, A. Eugenio, P. Fanelli, C. Fegan, S. Foda, A.M. Foote, J. Frye, J. Furletov, S. Gan, L. Gasparian, A. Gauzshtein, V. Gevorgyan, N. Gleason, C. Goetzen, K. Goncalves, A. Goryachev, V.S. Guo, L. Hakobyan, H. Hamdi, A. Han, S. Hardin, J. Huber, G.M. Hurley, A. Ireland, D.G. Ito, M.M. Jarvis, N.S. Jones, R.T. Kakoyan, V. Kalicy, G. Kamel, M. Kourkoumelis, C. Kuleshov, S. Kuznetsov, I. Larin, I. Lawrence, D. Lersch, D.I. Li, H. Li, W. Liu, B. Livingston, K. Lolos, G.J. Lyubovitskij, V. Mack, D. Marukyan, H. Matveev, V. McCaughan, M. McCracken, M. McGinley, W. McIntyre, J. Meyer, C.A. Miskimen, R. Mitchell, R.E. Mokaya, F. Nerling, F. Ng, L. Ostrovidov, A.I. Papandreou, Z. Patsyuk, M. Pauli, P. Pedroni, R. Pentchev, L. Peters, K.J. Phelps, W. Pooser, E. Qin, N. Reinhold, J. Ritchie, B.G. Robison, L. Romanov, D. Romero, C. Salgado, C. Schertz, A.M. Schumacher, R.A. Schwiening, J. Seth, K.K. Shen, X. Shepherd, M.R. Smith, E.S. Sober, D.I. Somov, A. Somov, S. Soto, O. Stevens, J.R. Strakovsky, I.I. Suresh, K. Tarasov, V. Taylor, S. Teymurazyan, A. Thiel, A. Vasileiadis, G. Werthmüller, D. Whitlatch, T. Wickramaarachchi, N. Williams, M. Xiao, T. Yang, Y. Zarling, J. Zhang, Z. Zhao, G. Zhou, Q. Zhou, X. Zihlmann, B. GlueX Collaboration

Abstract

We report on the measurement of the γp→J/ψp cross section from Eγ=11.8 GeV down to the threshold at 8.2 GeV using a tagged photon beam with the GlueX experiment. We find that the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section dσ/dt has an exponential slope of 1.67±0.39 GeV-2 at 10.7 GeV average energy. The LHCb pentaquark candidates Pc+ can be produced in the s channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions B(Pc+→J/ψp) and cross sections σ(γp→Pc+)×B(Pc+→J/ψp). © 2019 American Physical Society.

Published
2019

21. Beam asymmetry ς for the photoproduction of η and η′ mesons at Eγ=8.8 GeV

Author

Adhikari, S. Ali, A. Amaryan, M. Austregesilo, A. Barbosa, F. Barlow, J. Barnes, A. Barriga, E. Barsotti, R. Beattie, T.D. Berdnikov, V.V. Black, T. Boeglin, W. Boer, M. Briscoe, W.J. Britton, T. Brooks, W.K. Cannon, B.E. Cao, N. Chudakov, E. Cole, S. Cortes, O. Crede, V. Dalton, M.M. Daniels, T. Deur, A. Dobbs, S. Dolgolenko, A. Dotel, R. Dugger, M. Dzhygadlo, R. Egiyan, H. Erbora, T. Ernst, A. Eugenio, P. Fanelli, C. Fegan, S. Foda, A.M. Foote, J. Frye, J. Furletov, S. Gan, L. Gasparian, A. Gevorgyan, N. Gleason, C. Goetzen, K. Goncalves, A. Goryachev, V.S. Guo, L. Hakobyan, H. Hamdi, A. Huber, G.M. Hurley, A. Ireland, D.G. Ito, M.M. Jarvis, N.S. Jones, R.T. Kakoyan, V. Kalicy, G. Kamel, M. Kourkoumelis, C. Kuleshov, S. Larin, I. Lawrence, D. Lersch, D.I. Li, H. Li, W. Liu, B. Livingston, K. Lolos, G.J. Lyubovitskij, V. Mack, D. Marukyan, H. Mattione, P. Matveev, V. McCaughan, M. McCracken, M. McGinley, W. Meyer, C.A. Miskimen, R. Mitchell, R.E. Nerling, F. Ng, L. Ostrovidov, A.I. Papandreou, Z. Patsyuk, M. Paudel, C. Pauli, P. Pedroni, R. Pentchev, L. Peters, K.J. Phelps, W. Pooser, E. Qin, N. Reinhold, J. Ritchie, B.G. Robison, L. Romanov, D. Romero, C. Salgado, C. Schertz, A.M. Schumacher, R.A. Schwiening, J. Semenov, A.Y. Semenova, I.A. Seth, K.K. Shen, X. Shepherd, M.R. Smith, E.S. Sober, D.I. Somov, A. Somov, S. Soto, O. Staib, M. Stevens, J.R. Strakovsky, I.I. Suresh, K. Tarasov, V.V. Teymurazyan, A. Thiel, A. Vasileiadis, G. Whitlatch, T. Wickramaarachchi, N. Williams, M. Xiao, T. Yang, Y. Zarling, J. Zhang, Z. Zhao, G. Zhou, Q. Zhou, X. Zihlmann, B. The GlueX Collaboration

Abstract

We report on the measurement of the beam asymmetry ς for the reactions γ - p→pη and γ - p→pη′ from the GlueX experiment using an 8.2-8.8-GeV linearly polarized tagged photon beam incident on a liquid hydrogen target in Hall D at Jefferson Laboratory. These measurements are made as a function of momentum transfer -t with significantly higher statistical precision than our earlier η measurements and are the first measurements of η′ in this energy range. We compare the results to theoretical predictions based on t-channel quasiparticle exchange. We also compare the ratio of ςη to ςη′ to these models as this ratio is predicted to be sensitive to the amount of ss exchange in the production. We find that photoproduction of both η and η′ is dominated by natural parity exchange with little dependence on -t. © 2019 American Physical Society.

Published
2019

22. GlueX overview: status and some future plans

Author

Massachusetts Institute of Technology. Laboratory for Nuclear Science, Patsyuk, Maria, GlueX Collaboration, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Patsyuk, Maria, and GlueX Collaboration

Abstract

The GlueX experiment at Thomas Jefferson National Accelerator Facility (Jefferson Lab) has started data taking in late 2014 with its first commissioning beam. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed. Linearly-polarized photons were successfully produced through coherent bremsstrahlung. An upgrade of the particle identification (PID) system with a GlueX DIRC detector, planned for 2018, will allow identification of final state kaons. The construction of the GlueX DIRC has already started. One of the plans for GlueX is to study properties of short-range correlations (SRC) in nuclei, which will shed new light on the quark-gluon structure of bound nucleons.

Published
2018

23. GlueX overview: status and some future plans

Author

GlueX Collaboration, Patsyuk, Maria, Massachusetts Institute of Technology. Laboratory for Nuclear Science, and Patsyuk, Maria

Subjects
Physics, Particle physics, GlueX, 010308 nuclear & particles physics, Physics::Instrumentation and Detectors, QC1-999, 01 natural sciences, Particle identification, Nuclear physics, Upgrade, 0103 physical sciences, Physics::Accelerator Physics, High Energy Physics::Experiment, 010306 general physics, Nuclear Experiment
Abstract

The GlueX experiment at Thomas Jefferson National Accelerator Facility (Jefferson Lab) has started data taking in late 2014 with its first commissioning beam. All of the detector systems are now performing at or near design specifications and events are being fully reconstructed. Linearly-polarized photons were successfully produced through coherent bremsstrahlung. An upgrade of the particle identification (PID) system with a GlueX DIRC detector, planned for 2018, will allow identification of final state kaons. The construction of the GlueX DIRC has already started. One of the plans for GlueX is to study properties of short-range correlations (SRC) in nuclei, which will shed new light on the quark-gluon structure of bound nucleons.

Published
2017

24. Measurement of the beam asymmetry Σ for π0 and η photoproduction on the proton at Eγ=9 GeV

Author

Al Ghoul, H. Anassontzis, E.G. Austregesilo, A. Barbosa, F. Barnes, A. Beattie, T.D. Bennett, D.W. Berdnikov, V.V. Black, T. Boeglin, W. Briscoe, W.J. Brooks, W.K. Cannon, B.E. Chernyshov, O. Chudakov, E. Crede, V. Dalton, M.M. Deur, A. Dobbs, S. Dolgolenko, A. Dugger, M. Dzhygadlo, R. Egiyan, H. Eugenio, P. Fanelli, C. Foda, A.M. Frye, J. Furletov, S. Gan, L. Gasparian, A. Gerasimov, A. Gevorgyan, N. Goetzen, K. Goryachev, V.S. Guo, L. Hakobyan, H. Hardin, J. Henderson, A. Huber, G.M. Ireland, D.G. Ito, M.M. Jarvis, N.S. Jones, R.T. Kakoyan, V. Kamel, M. Klein, F.J. Kliemt, R. Kourkoumeli, C. Kuleshov, S. Kuznetsov, I. Lara, M. Larin, I. Lawrence, D. Levine, W.I. Livingston, K. Lolos, G.J. Lyubovitskij, V. Mack, D. Mattione, P.T. Matveev, V. McCaughan, M. McCracken, M. McGinley, W. McIntyre, J. Mendez, R. Meyer, C.A. Miskimen, R. Mitchell, R.E. Mokaya, F. Moriya, K. Nerling, F. Nigmatkulov, G. Ochoa, N. Ostrovidov, A.I. Papandreou, Z. Patsyuk, M. Pedroni, R. Pennington, M.R. Pentchev, L. Peters, K.J. Pooser, E. Pratt, B. Qiang, Y. Reinhold, J. Ritchie, B.G. Robison, L. Romanov, D. Salgado, C. Schumacher, R.A. Schwarz, C. Schwiening, J. Semenov, A.Y. Semenova, I.A. Seth, K.K. Shepherd, M.R. Smith, E.S. Sober, D.I. Somov, A. Somov, S. Soto, O. Sparks, N. Staib, M.J. Stevens, J.R. Strakovsky, I.I. Subedi, A. Tarasov, V. Taylor, S. Teymurazyan, A. Tolstukhin, I. Tomaradze, A. Toro, A. Tsaris, A. Vasileiadis, G. Vega, I. Walford, N.K. Werthmüller, D. Whitlatch, T. Williams, M. Wolin, E. Xiao, T. Zarling, J. Zhang, Z. Zihlmann, B. Mathieu, V. Nys, J. GlueX Collaboration

Subjects
Nuclear Experiment
Abstract

We report measurements of the photon beam asymmetry Σ for the reactions γ - p→pπ0 and γ - p→pη from the GlueX experiment using a 9 GeV linearly polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous π0 measurements and are the first η measurements in this energy regime. The results are compared with theoretical predictions based on t-channel, quasiparticle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models. © 2017 American Physical Society.

Published
2017

25. Measurement of the beam asymmetry $��$ for $��^0$ and $��$ photoproduction on the proton at $E_��= 9$ GeV

Author

GlueX Collaboration, Ghoul, H. Al, Anassontzis, E. G., Austregesilo, A., Barbosa, F., Barnes, A., Beattie, T. D., Bennett, D. W., Berdnikov, V. V., Black, T., Boeglin, W., Briscoe, W. J., Brooks, W. K., Cannon, B. E., Chernyshov, O., Chudakov, E., Crede, V., Dalton, M. M., Deur, A., Dobbs, S., Dolgolenko, A., Dugger, M., Dzhygadlo, R., Egiyan, H., Eugenio, P., Fanelli, C., Foda, A. M., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gerasimov, A., Gevorgyan, N., Goetzen, K., Goryachev, V. S., Guo, L., Hakobyan, H., Hardin, J., Henderson, A., Huber, G. M., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kamel, M., Klein, F. J., Kliemt, R., Kourkoumeli, C., Kuleshov, S., Kuznetsov, I., Lara, M., Larin, I., Lawrence, D., Levine, W. I., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Mattione, P. T., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Mendez, R., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Moriya, K., Nerling, F., Nigmatkulov, G., Ochoa, N., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pedroni, R., Pennington, M. R., Pentchev, L., Peters, K. J., Pooser, E., Pratt, B., Qiang, Y., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Salgado, C., Schumacher, R. A., Schwarz, C., Schwiening, J., Semenov, A. Yu., Semenova, I. A., Seth, K. K., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Sparks, N., Staib, M. J., Stevens, J. R., Strakovsky, I. I., Subedi, A., Tarasov, V., Taylor, S., Teymurazyan, A., Tolstukhin, I., Tomaradze, A., Toro, A., Tsaris, A., Vasileiadis, G., Vega, I., Walford, N. K., Werthmuller, D., Whitlatch, T., Williams, M., Wolin, E., Xiao, T., Zarling, J., Zhang, Z., Zihlmann, B., Mathieu, V., and Nys, J.

Subjects
FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

We report measurements of the photon beam asymmetry $��$ for the reactions $\vec��p\to p��^0$ and $\vec��p\to p��$ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $��^0$ measurements and are the first $��$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models., 6 pages, 6 figures, Published in Physical Review C: Rapid Communication

Published
2017
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26. Development of level-1 triggers for experiments at Jefferson lab

Author

A. Somov, null GlueX Collaboration, and null JLab Fast Electronics Group

Subjects
Engineering, Upgrade, GlueX, business.industry, Trigger rate, Detector, Electrical engineering, Electronics, business
Abstract

The upgrade of the CEBAF electron beam energy from 6 GeV to 12 GeV will expand the physics program at Jefferson Lab and result in upgrading three existing experimental halls and constructing a new detector GlueX in a fourth experimental Hall-D. This experiment requires a Level-1 trigger capable of running dead-timeless at 200 kHz total trigger rate. We have developed general-purpose custom-build electronics modules that meet these requirements. These modules are being implemented for other Jefferson Lab experiments. Description of the Level-1 triggers being developed at Jefferson Lab will be presented.

Published
2013
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27. 12 GeV detector technology at Jefferson Lab

Author

John P. Leckey and null GlueX Collaboration

Subjects
Physics, Photomultiplier, GlueX, Physics::Instrumentation and Detectors, business.industry, Electrical engineering, Particle accelerator, Avalanche photodiode, Photodiode, law.invention, Upgrade, Silicon photomultiplier, law, Nuclear electronics, Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, business
Abstract

The Thomas Jefferson National Accelerator Facility (JLab) is presently in the middle of an upgrade to increase the energy of its CW electron beam from 6 GeV to 12 GeV along with the addition of a fourth experimental hall. Driven both by necessity and availability, novel detectors and electronics modules have been used in the upgrade. One such sensor is the Silicon Photomultiplier (SiPM), specifically a Multi-Pixel Photon Counter (MPPC), which is an array of avalanche photodiode pixels operating in Geiger mode that are used to sense photons. The SiPMs replace conventional photomultiplier tubes and have several distinct advantages including the safe operation in a magnetic field and the lack of need for high voltage. Another key to 12 GeV success is advanced fast electronics. Jlab will use custom 250 MHz and 125 MHz 12-bit analog to digital converters (ADCs) and time to digital converters (TDCs) all of which take advantage of VME Switched Serial (VXS) bus with its GB/s high bandwidth readout capability. These new technologies will be used to readout drift chambers, calorimeters, spectrometers and other particle detectors at Jlab once the 12 GeV upgrade is complete. The largest experiment at Jlab utilizing these components is GlueX - an experiment in the newly constructed Hall D that will study the photoproduction of light mesons in the search for hybrid mesons. The performance of these components and their respective detectors will be presented.

Published
2013
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28. 12 GeV detector technology at Jefferson Lab.

Author

Leckey, John P. and GlueX Collaboration

Subjects
NUCLEAR counters, ELECTRON beams, PHOTOMULTIPLIERS, PHOTODIODES, MAGNETIC fields, PHOTON detectors
Abstract

The Thomas Jefferson National Accelerator Facility (JLab) is presently in the middle of an upgrade to increase the energy of its CW electron beam from 6 GeV to 12 GeV along with the addition of a fourth experimental hall. Driven both by necessity and availability, novel detectors and electronics modules have been used in the upgrade. One such sensor is the Silicon Photomultiplier (SiPM), specifically a Multi-Pixel Photon Counter (MPPC), which is an array of avalanche photodiode pixels operating in Geiger mode that are used to sense photons. The SiPMs replace conventional photomultiplier tubes and have several distinct advantages including the safe operation in a magnetic field and the lack of need for high voltage. Another key to 12 GeV success is advanced fast electronics. Jlab will use custom 250 MHz and 125 MHz 12-bit analog to digital converters (ADCs) and time to digital converters (TDCs) all of which take advantage of VME Switched Serial (VXS) bus with its GB/s high bandwidth readout capability. These new technologies will be used to readout drift chambers, calorimeters, spectrometers and other particle detectors at Jlab once the 12 GeV upgrade is complete. The largest experiment at Jlab utilizing these components is GlueX - an experiment in the newly constructed Hall D that will study the photoproduction of light mesons in the search for hybrid mesons. The performance of these components and their respective detectors will be presented. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
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29. Development of level-1 triggers for experiments at Jefferson lab.

Author

Somov, A., GlueX Collaboration, and JLab Fast Electronics Group

Subjects
ELECTRON beams, MESONS, PARTICLES (Nuclear physics), PARTICLE beams
Abstract

The upgrade of the CEBAF electron beam energy from 6 GeV to 12 GeV will expand the physics program at Jefferson Lab and result in upgrading three existing experimental halls and constructing a new detector GlueX in a fourth experimental Hall-D. This experiment requires a Level-1 trigger capable of running dead-timeless at 200 kHz total trigger rate. We have developed general-purpose custom-build electronics modules that meet these requirements. These modules are being implemented for other Jefferson Lab experiments. Description of the Level-1 triggers being developed at Jefferson Lab will be presented. [ABSTRACT FROM AUTHOR]

Published
2013
Full Text
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