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396 results on '"LEALI, M."'

1. First Measurement of Deeply Virtual Compton Scattering on the Neutron with Detection of the Active Neutron

Author

CLAS Collaboration, Hobart, A., Niccolai, S., Čuić, M., Kumerički, K., Achenbach, P., Alvarado, J. S., Armstrong, W. R., Atac, H., Avakian, H., Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Benkel, B., Benmokhtar, F., Bianconi, A., Biselli, A. S., Boiarinov, S., Bondi, M., Booth, W. A., Bossù, F., Brinkmann, K. -Th., Briscoe, W. J., Brooks, W. K., Bueltmann, S., Burkert, V. D., Cao, T., Capobianco, R., Carman, D. S., Chatagnon, P., Ciullo, G., Cole, P. L., Contalbrigo, M., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Fogler, C., Gates, K., Gavalian, G., Gilfoyle, G. P., Glazier, D., Gothe, R. W., Gotra, Y., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Heddle, D., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jiang, H., Jo, H. S., Joo, K., Kageya, T., Kim, A., Kim, W., Klimenko, V., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., MacGregor, I. J. D., Marchand, D., Mascagna, V., Maynes, M., McKinnon, B., Meziani, Z. E., Migliorati, S., Milner, R. G., Mineeva, T., Mirazita, M., Mokeev, V., Camacho, C. Muñoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Niculescu, G., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Rafael, S. Polcher, Poudel, J., Price, J. W., Prok, Y., Reed, T., Richards, J., Ripani, M., Ritman, J., Rossi, P., Golubenko, A. A., Salgado, C., Schadmand, S., Schmidt, A., Scott, Marshall B. C., Seroka, E. M., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Sparveris, N., Spreafico, M., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Tommaso, V., Voskanyan, H., Voutier, E., Watts, D. P, Wei, X., Williams, R., Wood, M. H., Xu, L., Zachariou, N., Zhang, J., Zhao, Z. W., and Zurek, M.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

Measuring Deeply Virtual Compton Scattering on the neutron is one of the necessary steps to understand the structure of the nucleon in terms of Generalized Parton Distributions (GPDs). Neutron targets play a complementary role to transversely polarized proton targets in the determination of the GPD $E$. This poorly known and poorly constrained GPD is essential to obtain the contribution of the quarks' angular momentum to the spin of the nucleon. DVCS on the neutron was measured for the first time selecting the exclusive final state by detecting the neutron, using the Jefferson Lab longitudinally polarized electron beam, with energies up to 10.6 GeV, and the CLAS12 detector. The extracted beam-spin asymmetries, combined with DVCS observables measured on the proton, allow a clean quark-flavor separation of the imaginary parts of the GPDs $H$ and $E$., Comment: 7 pages, 6 figures

Published
2024

2. Injection and capture of antiprotons in a Penning-Malmberg trap using a drift tube accelerator and degrader foil

Author

Amsler, C., Breuker, H., Bumbar, M., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Hori, M., Hunter, E. D., Killian, C., Kraxberger, V., Kuroda, N., Lanz, A., Leali, M., Maero, G., Malbrunot, C., Mascagna, V., Matsuda, Y., Maeckel, V., Migliorati, S., Murtagh, D. J., Nagata, Y., Nanda, A., Nowak, L., Rome, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., Venturelli, L., Weiser, A., Widmann, E., and Yamazaki, Y.

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

The Antiproton Decelerator (AD) at CERN provides antiproton bunches with a kinetic energy of 5.3 MeV. The Extra-Low ENergy Antiproton ring at CERN, commissioned at the AD in 2018, now supplies a bunch of electron-cooled antiprotons at a fixed energy of 100 keV. The MUSASHI antiproton trap was upgraded by replacing the radio-frequency quadrupole decelerator with a pulsed drift tube to re-accelerate antiprotons and optimize the injection energy into the degrader foils. By increasing the beam energy to 119 keV, a cooled antiproton accumulation efficiency of (26 +- 6)% was achieved., Comment: 22 pages, 8 figures

Published
2024

3. Beam Charge Asymmetries for Deeply Virtual Compton Scattering on the Proton at CLAS12

Author

Voutier, E., Burkert, V., Niccolai, S., Paremuzyan, R., Afanasev, A., Alvarado-Galeano, J. -S., Atoui, M., Barion, L., Battaglieri, M., Bernauer, J., Bianconi, A., Bondi, M., Briscoe, W., Camsonne, A., Capobianco, R., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Cole, P., Contalbrigo, M., Costantini, G., Defurne, M., Deur, A., De Vita, R., Diehl, S., Dupré, R., Elouadrhiri, L., Fernando, I., Filippi, A., Forest, T., Girod, F. -X., Gosta, G., Grames, J., Gueye, P., Habet, S., Hattawy, M., Higinbotham, D., Hobart, A., Hyde, C., Joo, K., Kim, A., Klimenko, V., Kubarovsky, V., Leali, M., Lenisa, P., Marchand, D., Marsicano, L., Mascagna, V., Matamoros, D., McCaughan, M., McKinnon, B., Migliorati, S., Mitra, H. S., Movsisyan, A., Muñoz-Camacho, C., Osipenko, M., Ouillon, M., Pappalardo, L., Pasquini, B., Pasyuk, E., Pilleux, N., Poelker, M., Raue, B., Ripani, M., Santos, R., Schmidt, A., Singh, R., Sokhan, D., Spreafico, M., Stoler, P., Strakovsky, I., Taiuti, M., Venturelli, L., Wang, P. -K., Wei, X., Zhao, Z., Collaboration, the CLAS, and Group, the Jefferson Lab Positron Working

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The parameterization of the nucleon structure through Generalized Parton Distributions (GPDs) shed a new light on the nucleon internal dynamics. For its direct interpretation, Deeply Virtual Compton Scattering (DVCS) is the golden channel for GPDs investigation. The DVCS process interferes with the Bethe-Heitler (BH) mechanism to constitute the leading order amplitude of the $eN \to eN\gamma$ process. The study of the $ep\gamma$ reaction with polarized positron and electron beams gives a complete set of unique observables to unravel the different contributions to the $ep \gamma$ cross section. This separates the different reaction amplitudes, providing a direct access to their real and imaginary parts which procures crucial constraints on the model dependences and associated systematic uncertainties on GPDs extraction. The real part of the BH-DVCS interference amplitude is particularly sensitive to the $D$-term which parameterizes the Gravitational Form Factors of the nucleon. The separation of the imaginary parts of the interference and DVCS amplitudes provides insights on possible higher-twist effects. We propose to measure the unpolarized and polarized Beam Charge Asymmetries (BCAs) of the $\vec{e}^{\pm}p \to e^{\pm}p \gamma$ process on an unpolarized hydrogen target with {\tt CLAS12}, using polarized positron and electron beams at 10.6 GeV. The azimuthal and $t$-dependences of the unpolarized and polarized BCAs will be measured over a large $(x_B,Q^2)$ phase space using a 100 day run with a luminosity of 0.66$\times 10^{35}$cm$^{-2}\cdot$s$^{-1}$., Comment: Proposal to the Jefferson Lab Program Advisory Committee (PAC51)

Published
2023

4. Beam Spin Asymmetry Measurements of Deeply Virtual $\pi^0$ Production with CLAS12

Author

Kim, A., Diehl, S., Joo, K., Kubarovsky, V., Achenbach, P., Akbar, Z., Alvarado, J. S., Armstrong, Whitney R., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Barion, L., Battaglieri, M., Bedlinskiy, I., Benkel, B., Bianconi, A., Biselli, A. S., Bondi, M., Bossù, F., Boiarinov, S., Brinkmann, K. T., Briscoe, W. J., Brooks, W. K., Bueltmann, S., Burkert, V. D., Capobianco, R., Carman, D. S., Carvajal, J. C., Celentano, A., Charles, G., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clary, B., Clash, G., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., DeVita, R., Defurne, M., Deur, A., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., ElAlaoui, A., ElFassi, L., Fegan, S., Filippi, A., Fogler, C., Gavalian, G., Gilfoyle, G. P., Gosta, G., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gothe, R. W., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Hung, Yu-Chun, Ilieva, Y., Ireland, D. G., Isupov, E., Jo, H. S., Johnston, R., Joosten, S., Khachatryan, M., Khanal, A., Kim, W., Klimenko, V., Kripko, A., Kuhn, S. E., Lanza, L., Leali, M., Kabir, M. L., Lee, S., Lenisa, P., Li, X., MacGregor, I . J . D., Marchand, D., Mascagna, V., McKinnon, B., Matamoros, D., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Moran, P., MunozCamacho, C., Naidoo, P., Neupane, K., Nguyen, D., Niccolai, S., Niculescu, G., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Radic, A., Ramasubramanian, N., Reed, Trevor, Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatié, F., Salgado, C., Schadmand, S., Schmidt, A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Sokhan, D., Sparveris, N., Spreafico, M., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J., Trotta, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Wishart, R., Wood, M. H., Yurov, M., Zachariou, N., Zhang, J., Ziegler, V., and Zurek, M.

Subjects
Nuclear Experiment
Abstract

The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive $\pi^0$ production in a wide kinematic region with the photon virtualities $Q^2$ up to 8 GeV$^2$ and the Bjorken scaling variable $x_B$ in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions.The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD $\bar E_T$, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the proton's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities., Comment: arXiv admin note: substantial text overlap with arXiv:2210.14557

Published
2023

5. Upgrade of the positron system of the ASACUSA-Cusp experiment

Author

Lanz, A., Amsler, C., Breuker, H., Bumbar, M., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Hunter, E. D., Killian, C., Kraxberger, V., Kuroda, N., Leali, M., Maero, G., Malbrunot, C., Mascagna, V., Matsuda, Y., Mäckel, V., Migliorati, S., Murtagh, D. J., Nanda, A., Nowak, L., Gustafsson, F. Parnefjord, Rheinfrank, S., Romé, M., Simon, M. C., Tajima, M., Toso, V., Uggerhøj, U., Ulmer, S., Venturelli, L., Weiser, A., Widmann, E., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Atomic Physics, Physics - Plasma Physics
Abstract

The ASACUSA-Cusp collaboration has recently upgraded the positron system to improve the production of antihydrogen. Previously, the experiment suffered from contamination of the vacuum in the antihydrogen production trap due to the transfer of positrons from the high pressure region of a buffer gas trap. This contamination reduced the lifetime of antiprotons. By adding a new positron accumulator and therefore decreasing the number of transfer cycles, the contamination of the vacuum has been reduced. Further to this, a new rare gas moderator and buffer gas trap, previously used at the Aarhus University, were installed. Measurements from Aarhus suggested that the number of positrons could be increased by a factor of four in comparison to the old system used at CERN. This would mean a reduction of the time needed for accumulating a sufficient number of positrons (of the order of a few million) for an antihydrogen production cycle. Initial tests have shown that the new system yields a comparable number of positrons to the old system., Comment: 10 pages, 5 figures, under consideration for the Special Collection "Non-Neutral Plasmas: Achievements and Perspectives" in JPP

Published
2023

6. Slow positron production and storage for the ASACUSA-Cusp experiment

Author

Murtagh, D. J., Amsler, C., Breuker, H., Bumbar, M., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Hunter, E. D., Killian, C., Kraxberger, V., Kuroda, N., Lanz, A., Leali, M., Maero, G., Mal\-bru\-not, C., Mascagna, V., Matsuda, Y., Mäckel, V., Migliorati, S., Nanda, A., Nowak, L., Gustafsson, F. Parnefjord, Rheinfrank, S., Romé, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., Venturelli, L., Weiser, A., Widmann, E., Wolz, T., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Plasma Physics, Physics - Atomic Physics
Abstract

The ASACUSA Cusp experiment requires the production of dense positron plasmas with a high repetition rate to produce a beam of antihydrogen. In this work, details of the positron production apparatus used for the first observation of the antihydrogen beam, and subsequent measurements are described in detail. This apparatus replaced the previous compact trap design resulting in an improvement in positron accumulation by a factor of ($52\pm3)$, Comment: 9 pages, 7 figures

Published
2023

7. Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

Author

Accardi, A., Achenbach, P., Adhikari, D., Afanasev, A., Akondi, C. S., Akopov, N., Albaladejo, M., Albataineh, H., Albrecht, M., Almeida-Zamora, B., Amaryan, M., Androić, D., Armstrong, W., Armstrong, D. S., Arratia, M., Arrington, J., Asaturyan, A., Austregesilo, A., Avagyan, H., Averett, T., Gayoso, C. Ayerbe, Bacchetta, A., Balantekin, A. B., Baltzell, N., Barion, L., Barry, P. C., Bashir, A., Battaglieri, M., Bellini, V., Belov, I., Benhar, O., Benkel, B., Benmokhtar, F, Bentz, W., Bertone, V., Bhatt, H., Bianconi, A., Bibrzycki, L., Bijker, R., Binosi, D., Biswas, D., Boër, M., Boeglin, W., Bogacz, S. A., Boglione, M., Bondí, M., Boos, E. E., Bosted, P., Bozzi, G., Brash, E. J., Briceño, R. A., Brindza, P. D., Briscoe, W. J., Brodsky, S. J, Brooks, W. K., Burkert, V. D., Camsonne, A., Cao, T., Cardman, L. S., Carman, D. S., Carpinelli, M, Cates, G. D., Caylor, J., Celentano, A., Celiberto, F. G., Cerutti, M., Chang, Lei, Chatagnon, P., Chen, C., Chen, J-P, Chetry, T., Christopher, A., Christy, E., Chudakov, E., Cisbani, E., Cloët, I. C., Cobos-Martinez, J. J., Cohen, E. O., Colangelo, P., Cole, P. L., Constantinou, M., Contalbrigo, M., Costantini, G., Cosyn, W., Cotton, C., Courtoy, A., Dusa, S. Covrig, Crede, V., Cui, Z. -F., D'Angelo, A., Döring, M., Dalton, M. M., Danilkin, I., Davydov, M., Day, D., De Fazio, F., De Napoli, M., De Vita, R., Dean, D. J., Defurne, M., Deur, A., Devkota, B., Dhital, S., Di Nezza, P., Diefenthaler, M., Diehl, S., Dilks, C., Ding, M., Djalali, C., Dobbs, S., Dupré, R., Dutta, D., Edwards, R. G., Egiyan, H., Ehinger, L., Eichmann, G., Elaasar, M., Elouadrhiri, L., Alaoui, A. El, Fassi, L. El, Emmert, A., Engelhardt, M., Ent, R., Ernst, D. J, Eugenio, P., Evans, G., Fanelli, C., Fegan, S., Fernández-Ramírez, C., Fernandez, L. A., Fernando, I. P., Filippi, A., Fischer, C. S., Fogler, C., Fomin, N., Frankfurt, L., Frederico, T., Freese, A., Fu, Y., Gamberg, L., Gan, L., Gao, F., Garcia-Tecocoatzi, H., Gaskell, D., Gasparian, A., Gates, K, Gavalian, G., Ghoshal, P. K., Giachino, A., Giacosa, F., Giannuzzi, F., Gilfoyle, G. -P., Girod, F-X, Glazier, D. I., Gleason, C., Godfrey, S., Goity, J. L., Golubenko, A. A., Gonzàlez-Solís, S., Gothe, R. W., Gotra, Y., Griffioen, K., Grocholski, O., Grube, B., Guèye, P., Guo, F. -K., Guo, Y., Guo, L., Hague, T. J., Hammoud, N., Hansen, J. -O., Hattawy, M., Hauenstein, F., Hayward, T., Heddle, D., Heinrich, N., Hen, O., Higinbotham, D. W., Higuera-Angulo, I. M., Blin, A. N. Hiller, Hobart, A., Hobbs, T., Holmberg, D. E, Horn, T., Hoyer, P., Huber, G. M., Hurck, P., Hutauruk, P. T. P., Ilieva, Y., Illari, I., Ireland, D. G, Isupov, E. L., Italiano, A., Jaegle, I., Jarvis, N. S., Jenkins, DJ, Jeschonnek, S., Ji, C-R., Jo, H. S., Jones, M., Jones, R. T., Jones, D. C., Joo, K., Junaid, M., Kageya, T., Kalantarians, N., Karki, A., Karyan, G., Katramatou, A. T., Kay, S. J. D, Kazimi, R., Keith, C. D., Keppel, C., Kerbizi, A., Khachatryan, V., Khanal, A., Khandaker, M., Kim, A., Kinney, E. R., Kohl, M., Kotzinian, A., Kriesten, B. T., Kubarovsky, V., Kubis, B., Kuhn, S. E., Kumar, V., Kutz, T., Leali, M., Lebed, R. F., Lenisa, P., Leskovec, L., Li, S., Li, X., Liao, J., Lin, H. -W., Liu, L., Liuti, S., Liyanage, N., Lu, Y., MacGregor, I. J. D., Mack, D. J., Maiani, L, Mamo, K. A., Mandaglio, G., Mariani, C., Markowitz, P., Marukyan, H., Mascagna, V., Mathieu, V., Maxwell, J., Mazouz, M., McCaughan, M., McKeown, R. D., McKinnon, B., Meekins, D., Melnitchouk, W., Metz, A., Meyer, C. A., Meziani, Z. -E., Mezrag, C., Michaels, R., Miller, G. A., Mineeva, T., Miramontes, A. S., Mirazita, M., Mizutani, K., Mkrtchyan, H., Mkrtchyan, A., Moffit, B., Mohanmurthy, P., Mokeev, V. I., Monaghan, P., Montaña, G., Montgomery, R., Moretti, A., Chàvez, J. M. Morgado, Mosel, U., Movsisyan, A., Musico, P., Nadeeshani, S. A, Nadolsky, P. M., Nakamura, S. X., Nazeer, J., Nefediev, A. V., Neupane, K., Nguyen, D., Niccolai, S., Niculescu, I., Niculescu, G., Nocera, E. R., Nycz, M., Olness, F. I., Ortega, P. G., Osipenko, M., Pace, E., Pandey, B, Pandey, P., Papandreou, Z., Papavassiliou, J., Pappalardo, L. L., Paredes-Torres, G., Paremuzyan, R., Park, S., Parsamyan, B., Paschke, K. D., Pasquini, B., Passemar, E., Pasyuk, E., Patel, T., Paudel, C., Paul, S. J., Peng, J-C., Pentchev, L., Perrino, R., Perry, R. J., Peters, K., Petratos, G. G., Phelps, W., Piasetzky, E., Pilloni, A., Pire, B., Pitonyak, D., Pitt, M. L., Polosa, A. D., Pospelov, M., Postuma, A. C., Poudel, J., Preet, L., Prelovsek, S., Price, J. W., Prokudin, A., Puckett, A. J. R., Pybus, J. R., Qin, S. -X., Qiu, J. -W., Radici, M., Rashidi, H., Rathnayake, A. D, Raue, B. A., Reed, T., Reimer, P. E., Reinhold, J., Richard, J. -M., Rinaldi, M., Ringer, F., Ripani, M., Ritman, J., West, J. Rittenhouse, Rivero-Acosta, A., Roberts, C. D., Rodas, A., Rodini, S., Rodríguez-Quintero, J., Rogers, T. C., Rojo, J., Rossi, P., Rossi, G. C., Salmè, G., Santiesteban, S. N., Santopinto, E., Sargsian, M., Sato, N., Schadmand, S., Schmidt, A., Schmidt, S. M, Schnell, G., Schumacher, R. A., Schweitzer, P., Scimemi, I., Scott, K. C, Seay, D. A, Segovia, J., Semenov-Tian-Shansky, K., Seryi, A., Sharda, A. S, Shepherd, M. R., Shirokov, E. V., Shrestha, S., Shrestha, U., Shvedunov, V. I., Signori, A., Slifer, K. J., Smith, W. A., Somov, A., Souder, P., Sparveris, N., Spizzo, F., Spreafico, M., Stepanyan, S., Stevens, J. R., Strakovsky, I. I., Strauch, S., Strikman, M., Su, S., Sumner, B. C. L., Sun, E., Suresh, M., Sutera, C., Swanson, E. S., Szczepaniak, A. P, Sznajder, P., Szumila-Vance, H., Szymanowski, L., Tadepalli, A. -S., Tadevosyan, V., Tamang, B., Tarasov, V. V., Thiel, A., Tong, X. -B., Tyson, R., Ungaro, M., Urciuoli, G. M., Usman, A., Valcarce, A., Vallarino, S., Vaquera-Araujo, C. A., Venturelli, L., Vera, F., Vladimirov, A., Vossen, A., Wagner, J., Wei, X., Weinstein, L. B., Weiss, C., Williams, R., Winney, D., Wojtsekhowski, B., Wood, M. H., Xiao, T., Xu, S. -S., Ye, Z., Yero, C., Yuan, C. -P., Yurov, M., Zachariou, N., Zhang, Z., Zhao, Z. W., Zhao, Y., Zheng, X., Zhou, X., Ziegler, V., Zihlmann, B., de Paula, W, and de Téramond, G. F.

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

This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena., Comment: Updates to the list of authors; Preprint number changed from theory to experiment; Updates to sections 4 and 6, including additional figures

Published
2023

8. SDR, EVC, and SDREVC: Limitations and Extensions

Author

Hunter, E. D., Amsler, C., Breuker, H., Bumbar, M., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Killian, C., Kraxberger, V., Kuroda, N., Lanz, A., Leali, M., Maero, G., Malbrunot, C., Mascagna, V., Matsuda, Y., Mäckel, V., Migliorati, S., Murtagh, D. J., Nanda, A., Nowak, L., Gustafsson, F. Parnefjord, Rheinfrank, S., Romé, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., Venturelli, L., Weiser, A., Widmann, E., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Plasma Physics
Abstract

Methods for reducing the radius, temperature, and space charge of nonneutral plasma are usually reported for conditions which approximate an ideal Penning Malmberg trap. Here we show that (1) similar methods are still effective under surprisingly adverse circumstances: we perform SDR and SDREVC in a strong magnetic mirror field using only 3 out of 4 rotating wall petals. In addition, we demonstrate (2) an alternative to SDREVC, using e-kick instead of EVC and (3) an upper limit for how much plasma can be cooled to T < 20 K using EVC. This limit depends on the space charge, not on the number of particles or the plasma density., Comment: Version 2: a small discrepancy between the N values for Table 1 and Fig. 3 led to an investigation of the charge counting diagnostic. There is a small energy dependence which only became apparent following improvements to pre-SDREVC. The pulsed dump was modified to reduce this dependence. The data for Table 1 and Fig. 3 was taken again with the improved methods

Published
2023

9. Antiproton annihilation at rest in thin solid targets and comparison with Monte Carlo simulations

Author

Amsler, C., Breuker, H., Bumbar, M., Cerwenka, M., Costantini, G., Ferragut, R., Fleck, M., Giammarchi, M., Gligorova, A., Gosta, G., Hunter, E. D., Killian, C., Kolbinger, B., Kraxberger, V., Kuroda, N., Lackner, M., Leali, M., Maero, G., Mascagna, V., Matsuda, Y., Migliorati, S., Murtagh, D. J., Nanda, A., Nowak, L., Rheinfrank, S., Romé, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., van Beuzekom, M., Venturelli, L., Weiser, A., Widmann, E., Yamazaki, Y., and Zmeskal, J.

Published
2024
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10. Strong interaction physics at the luminosity frontier with 22 GeV electrons at Jefferson Lab

Author

Accardi, A., Achenbach, P., Adhikari, D., Afanasev, A., Akondi, C. S., Akopov, N., Albaladejo, M., Albataineh, H., Albrecht, M., Almeida-Zamora, B., Amaryan, M., Androić, D., Armstrong, W., Armstrong, D. S., Arratia, M., Arrington, J., Asaturyan, A., Austregesilo, A., Avakian, H., Averett, T., Gayoso, C. Ayerbe, Bacchetta, A., Balantekin, A. B., Baltzell, N., Barion, L., Barry, P. C., Bashir, A., Battaglieri, M., Bellini, V., Belov, I., Benhar, O., Benkel, B., Benmokhtar, F., Bentz, W., Bertone, V., Bhatt, H., Bianconi, A., Bibrzycki, L., Bijker, R., Binosi, D., Biswas, D., Boër, M., Boeglin, W., Bogacz, S. A., Boglione, M., Bondí, M., Boos, E. E., Bosted, P., Bozzi, G., Brash, E. J., Briceño, R. A., Brindza, P. D., Briscoe, W. J., Brodsky, S. J., Brooks, W. K., Burkert, V. D., Camsonne, A., Cao, T., Cardman, L. S., Carman, D. S., Carpinelli, M., Cates, G. D., Caylor, J., Celentano, A., Celiberto, F. G., Cerutti, M., Chang, L., Chatagnon, P., Chen, C., Chen, J.-P., Chetry, T., Christopher, A., Christy, E., Chudakov, E., Cisbani, E., Cloët, I. C., Cobos-Martinez, J. J., Cohen, E. O., Colangelo, P., Cole, P. L., Constantinou, M., Contalbrigo, M., Costantini, G., Cosyn, W., Cotton, C., Courtoy, A., Dusa, S. Covrig, Crede, V., Cui, Z.-F., D’Angelo, A., Döring, M., Dalton, M. M., Danilkin, I., Davydov, M., Day, D., De Fazio, F., De Napoli, M., De Vita, R., Dean, D. J., Defurne, M., de Paula, W., de Téramond, G. F., Deur, A., Devkota, B., Dhital, S., Di Nezza, P., Diefenthaler, M., Diehl, S., Dilks, C., Ding, M., Djalali, C., Dobbs, S., Dupré, R., Dutta, D., Edwards, R. G., Egiyan, H., Ehinger, L., Eichmann, G., Elaasar, M., Elouadrhiri, L., Alaoui, A. El, Fassi, L. El, Emmert, A., Engelhardt, M., Ent, R., Ernst, D. J., Eugenio, P., Evans, G., Fanelli, C., Fegan, S., Fernández-Ramírez, C., Fernandez, L. A., Fernando, I. P., Filippi, A., Fischer, C. S., Fogler, C., Fomin, N., Frankfurt, L., Frederico, T., Freese, A., Fu, Y., Gamberg, L., Gan, L., Gao, F., Garcia-Tecocoatzi, H., Gaskell, D., Gasparian, A., Gates, K., Gavalian, G., Ghoshal, P. K., Giachino, A., Giacosa, F., Giannuzzi, F., Gilfoyle, G.-P., Girod, F.-X., Glazier, D. I., Gleason, C., Godfrey, S., Goity, J. L., Golubenko, A. A., Gonzàlez-Solís, S., Gothe, R. W., Gotra, Y., Griffioen, K., Grocholski, O., Grube, B., Guèye, P., Guo, F.-K., Guo, Y., Guo, L., Hague, T. J., Hammoud, N., Hansen, J.-O., Hattawy, M., Hauenstein, F., Hayward, T., Heddle, D., Heinrich, N., Hen, O., Higinbotham, D. W., Higuera-Angulo, I. M., Hiller Blin, A. N., Hobart, A., Hobbs, T., Holmberg, D. E., Horn, T., Hoyer, P., Huber, G. M., Hurck, P., Hutauruk, P. T. P., Ilieva, Y., Illari, I., Ireland, D. G., Isupov, E. L., Italiano, A., Jaegle, I., Jarvis, N. S., Jenkins, D. J., Jeschonnek, S., Ji, C.-R., Jo, H. S., Jones, M., Jones, R. T., Jones, D. C., Joo, K., Junaid, M., Kageya, T., Kalantarians, N., Karki, A., Karyan, G., Katramatou, A. T., Kay, S. J. D., Kazimi, R., Keith, C. D., Keppel, C., Kerbizi, A., Khachatryan, V., Khanal, A., Khandaker, M., Kim, A., Kinney, E. R., Kohl, M., Kotzinian, A., Kriesten, B. T., Kubarovsky, V., Kubis, B., Kuhn, S. E., Kumar, V., Kutz, T., Leali, M., Lebed, R. F., Lenisa, P., Leskovec, L., Li, S., Li, X., Liao, J., Lin, H.-W., Liu, L., Liuti, S., Liyanage, N., Lu, Y., MacGregor, I. J. D., Mack, D. J., Maiani, L., Mamo, K. A., Mandaglio, G., Mariani, C., Markowitz, P., Marukyan, H., Mascagna, V., Mathieu, V., Maxwell, J., Mazouz, M., McCaughan, M., McKeown, R. D., McKinnon, B., Meekins, D., Melnitchouk, W., Metz, A., Meyer, C. A., Meziani, Z.-E., Mezrag, C., Michaels, R., Miller, G. A., Mineeva, T., Miramontes, A. S., Mirazita, M., Mizutani, K., Mkrtchyan, A., Mkrtchyan, H., Moffit, B., Mohanmurthy, P., Mokeev, V. I., Monaghan, P., Montaña, G., Montgomery, R., Moretti, A., Chàvez, J. M. Morgado, Mosel, U., Movsisyan, A., Musico, P., Nadeeshani, S. A., Nadolsky, P. M., Nakamura, S. X., Nazeer, J., Nefediev, A. V., Neupane, K., Nguyen, D., Niccolai, S., Niculescu, I., Niculescu, G., Nocera, E. R., Nycz, M., Olness, F. I., Ortega, P. G., Osipenko, M., Pace, E., Pandey, B., Pandey, P., Papandreou, Z., Papavassiliou, J., Pappalardo, L. L., Paredes-Torres, G., Paremuzyan, R., Park, S., Parsamyan, B., Paschke, K. D., Pasquini, B., Passemar, E., Pasyuk, E., Patel, T., Paudel, C., Paul, S. J., Peng, J.-C., Pentchev, L., Perrino, R., Perry, R. J., Peters, K., Petratos, G. G., Phelps, W., Piasetzky, E., Pilloni, A., Pire, B., Pitonyak, D., Pitt, M. L., Polosa, A. D., Pospelov, M., Postuma, A. C., Poudel, J., Preet, L., Prelovsek, S., Price, J. W., Prokudin, A., Puckett, A. J. R., Pybus, J. R., Qin, S.-X., Qiu, J.-W., Radici, M., Rashidi, H., Rathnayake, A. D., Raue, B. A., Reed, T., Reimer, P. E., Reinhold, J., Richard, J.-M., Rinaldi, M., Ringer, F., Ripani, M., Ritman, J., West, J. Rittenhouse, Rivero-Acosta, A., Roberts, C. D., Rodas, A., Rodini, S., Rodríguez-Quintero, J., Rogers, T. C., Rojo, J., Rossi, P., Rossi, G. C., Salmè, G., Santiesteban, S. N., Santopinto, E., Sargsian, M., Sato, N., Schadmand, S., Schmidt, A., Schmidt, S. M., Schnell, G., Schumacher, R. A., Schweitzer, P., Scimemi, I., Scott, K. C., Seay, D. A., Segovia, J., Semenov-Tian-Shansky, K., Seryi, A., Sharda, A. S., Shepherd, M. R., Shirokov, E. V., Shrestha, S., Shrestha, U., Shvedunov, V. I., Signori, A., Slifer, K. J., Smith, W. A., Somov, A., Souder, P., Sparveris, N., Spizzo, F., Spreafico, M., Stepanyan, S., Stevens, J. R., Strakovsky, I. I., Strauch, S., Strikman, M., Su, S., Sumner, B. C. L., Sun, E., Suresh, M., Sutera, C., Swanson, E. S., Szczepaniak, A. P., Sznajder, P., Szumila-Vance, H., Szymanowski, L., Tadepalli, A.-S., Tadevosyan, V., Tamang, B., Tarasov, V. V., Thiel, A., Tong, X.-B., Tyson, R., Ungaro, M., Urciuoli, G. M., Usman, A., Valcarce, A., Vallarino, S., Vaquera-Araujo, C. A., Venturelli, L., Vera, F., Vladimirov, A., Vossen, A., Wagner, J., Wei, X., Weinstein, L. B., Weiss, C., Williams, R., Winney, D., Wojtsekhowski, B., Wood, M. H., Xiao, T., Xu, S.-S., Ye, Z., Yero, C., Yuan, C.-P., Yurov, M., Zachariou, N., Zhang, Z., Zhao, Y., Zhao, Z. W., Zheng, X., Zhou, X., Ziegler, V., and Zihlmann, B.

Published
2024
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11. First measurement of hard exclusive $\pi^- \Delta^{++}$ electroproduction beam-spin asymmetries off the proton

Author

Diehl, S., Trotta, N., Joo, K., Achenbach, P., Akbar, Z., Armstrong, W. R., Atac, H., Avakian, H., Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossu, F., Brinkmann, K. -T., Briscoe, W. J., Bulumulla, D., Burkert, V., Capobianco, R., Carman, D. S., Carvajal, J. C., Celentano, A., Charles, G., Chatagnon, P., Chesnokov, V., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Deur, A., Djalali, C., Dupre, R., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Gavalian, G., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Gotra, Y., Griffioen, K., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Illari, I., Ireland, D. G., Isupov, E. L., Jo, H. S., Johnston, R., Keller, D., Khachatryan, M., Khanal, A., Kim, A., Kim, W., Klimenko, V., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lagerquist, V., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., MacGregor, I . J . D., Marchand, D., Mascagna, V., Matousek, G., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Milner, R. G., Mineeva, T., Mirazita, M., Mokeev, V., Moran, P., Camacho, C. Munoz, Naidoo, P., Neupane, K., Niccolai, S., Niculescu, G., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Radic, A., Raue, B. A., Reed, T., Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatie, F., Salgado, C., Schadmand, S., Schmidt, A., Sharabian, Y. G., Shrestha, U., Sokhan, D., Sparveris, N., Spreafico, M., Stepanyan, S., Strakovsky, I., Strauch, S., Turisini, M., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Williams, R., Wishart, R., Wood, M. H., Yurov, M., Zachariou, N., Zhao, Z. W., and Zurek, M.

Subjects
High Energy Physics - Experiment
Abstract

The polarized cross section ratio $\sigma_{LT'}/\sigma_{0}$ from hard exclusive $\pi^{-} \Delta^{++}$ electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2 GeV / 10.6 GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5 GeV$^{2}$ up to 7 GeV$^{2}$. The reaction provides a novel access to the $d$-quark content of the nucleon and to $p \rightarrow \Delta^{++}$ transition generalized parton distributions. A comparison to existing results for hard exclusive $\pi^{+} n$ and $\pi^{0} p$ electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.

Published
2023
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12. A new direct detection electron scattering experiment to search for the X17 particle

Author

Dutta, D., Gao, H., Gasparian, A., Hague, T. J., Liyanage, N., Paremuzyan, R., Peng, C., Xiong, W., Achenbach, P., Ahmidouch, A., Ali, S., Avakian, H., Ayerbe-Gayoso, C., Bai, X., Battaglieri, M., Bhatt, H., Bianconi, A., Boyd, J., Byer, D., Cole, P. L., Costantini, G., Davis, S., De Napoli, M., De Vita, R., Devkota, B., Dharmasena, B., Dunne, J., Fassi, L. El, Gamage, V., Gan, L., Gnanvo, K., Gosta, G., Higinbotham, D., Howell, C., Jeffas, S., Jian, S., Karki, A., Karki, B., Khachatryan, V., Khandaker, M., Kubarovsky, V., Larin, I., Leali, M., Mascagna, V., Matousek, G., Migliorati, S., Miskimen, R., Mohanmurthy, P., Nguyen, H., Pasyuk, E., Rathnayake, A., West, J. Rittenhouse, Shahinyan, A., Smith, A., Stepanyan, S., van Nieuwenhuizen, E., Venturelli, L., Yu, B., Zhao, Z., and Zhou, J.

Subjects
Nuclear Experiment
Abstract

A new electron scattering experiment (E12-21-003) to verify and understand the nature of hidden sector particles, with particular emphasis on the so-called X17 particle, has been approved at Jefferson Lab. The search for these particles is motivated by new hidden sector models introduced to account for a variety of experimental and observational puzzles: excess in $e^+e^-$ pairs observed in multiple nuclear transitions, the 4.2$\sigma$ disagreement between experiments and the standard model prediction for the muon anomalous magnetic moment, and the small-scale structure puzzle in cosmological simulations. The aforementioned X17 particle has been hypothesized to account for the excess in $e^+e^-$ pairs observed from the $^8$Be M1, $^4$He M0, and, most recently, $^{12}$C E1 nuclear transitions to their ground states observed by the ATOMKI group. This experiment will use a high resolution electromagnetic calorimeter to search for or set new limits on the production rate of the X17 and other hidden sector particles in the $3 - 60$ MeV mass range via their $e^+e^-$ decay (or $\gamma\gamma$ decay with limited tracking). In these models, the $1 - 100$ MeV mass range is particularly well-motivated and the lower part of this range still remains unexplored. Our proposed direct detection experiment will use a magnetic-spectrometer-free setup (the PRad apparatus) to detect all three final state particles in the visible decay of a hidden sector particle for an effective control of the background and will cover the proposed mass range in a single setting. The use of the well-demonstrated PRad setup allows for an essentially ready-to-run and uniquely cost-effective search for hidden sector particles in the $3 - 60$ MeV mass range with a sensitivity of 8.9$\times$10$^{-8}$ - 5.8$\times$10$^{-9}$ to $\epsilon^2$, the square of the kinetic mixing interaction constant between hidden and visible sectors., Comment: 6 pages, 7 figures. arXiv admin note: substantial text overlap with arXiv:2108.13276

Published
2023

13. First CLAS12 measurement of DVCS beam-spin asymmetries in the extended valence region

Author

CLAS Collaboration, Christiaens, G., Defurne, M., Sokhan, D., Achenbach, P., Akbar, Z., Amaryan, M. J., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Booth, W. A., Bossù, F., Boiarinov, S., Brinkmann, K. -Th., Briscoe, W. J., Bueltmann, S., Bulumulla, D., Burkert, V. D., Cao, T., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clash, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Deur, A., Diehl, S., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Gates, K., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hobart, A., Holmberg, D. E., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Kabir, M. L., Keller, D., Khachatryan, M., Khanal, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lagerquist, V., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., Livingston, K., MacGregor, I . J . D., Marchand, D., Mascagna, V., Matousek, G., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Milner, R. G., Mineeva, T., Mirazita, M., Mokeev, V., Molina, E., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Radic, A., Ramasubramanian, N., Raue, B. A., Reed, T., Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatié, F., Salgado, C., Schadmand, S., Schmidt, A., Scott, M. B. C., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sparveris, N., Spreafico, M., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Turisini, M., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Williams, R., Wishart, R., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., Ziegler, V., and Zurek, M.

Subjects
High Energy Physics - Experiment
Abstract

Deeply virtual Compton scattering (DVCS) allows one to probe Generalized Parton Distributions (GPDs) describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarised protons. The results greatly extend the $Q^2$ and Bjorken-$x$ phase space beyond the existing data in the valence region and provide over 2000 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies., Comment: Revised Figure 4 and discussion around the number of effective ANNs after Bayesian reweighting

Published
2022

14. A multidimensional study of the structure function ratio $\sigma_{LT'}/\sigma_{0}$ from hard exclusive $\pi^+$ electro-production off protons in the GPD regime

Author

Diehl, S., Kim, A., Joo, K., Achenbach, P., Akbar, Z., Amaryan, M. J., Atac, H., Avagyan, H., Gayoso, C. Ayerbe, Baashen, L., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Booth, W. A., Bossu, F., Boiarinov, S., Brinkmann, K. -Th., Briscoe, W. J., Bueltmann, S., Bulumulla, D., Burkert, V. D., Carman, D. S., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clash, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Gotra, Y., Grifoen, K. A., Guidal, M., Hafdi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Khachatryan, M., Khanal, A., Kim, W., Kripko, A., Kubarovsky, V., Lagerquist, V., Laget, J. -M., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., Livingston, K., MacGregor, I . J. D., Marchand, D., Mascagna, V., McKinnon, B., Meziani, Z. E., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Molina, Esteban, Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Reed, Trevor, Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatie, F., Salgado, C., Schadmand, S., Schmidt, A., Sharabian, Y., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Spreafco, M., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Turisini, M., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Williams, R., Wishart, R., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., and Zurek, M.

Subjects
High Energy Physics - Experiment
Abstract

A multidimensional extraction of the structure function ratio $\sigma_{LT'}/\sigma_{0}$ from the hard exclusive $\vec{e} p \to e^\prime n \pi^+$ reaction above the resonance region has been performed. The study was done based on beam-spin asymmetry measurements using a 10.6 GeV incident electron beam on a liquid-hydrogen target and the CLAS12 spectrometer at Jefferson Lab. The measurements focus on the very forward regime ($t/Q^{2}$ $\ll$ 1) with a wide kinematic range of $x_{B}$ in the valence regime (0.17 $<$ $x_{B}$ $<$ 0.55), and virtualities $Q^{2}$ ranging from 1.5 GeV$^{2}$ up to 6 GeV$^{2}$. The results and their comparison to theoretical models based on Generalized Parton Distributions demonstrate the sensitivity to chiral-odd GPDs and the directly related tensor charge of the nucleon. In addition, the data is compared to an extension of a Regge formalism at high photon virtualities. It was found that the Regge model provides a better description at low $Q^{2}$, while the GPD model is more appropriate at high $Q^{2}$., Comment: arXiv admin note: text overlap with arXiv:2007.15677

Published
2022
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15. First Measurement of $\Lambda$ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

Author

Chetry, T., Fassi, L. El, Brooks, W. K., Dupré, R., Alaoui, A. El, Hafidi, K., Achenbach, P., Adhikari, K. P., Akbar, Z., Armstrong, W. R., Arratia, M., Atac, H., Avakian, H., Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Booth, W. A., Bossù, F., Boiarinov, S., Brinkmann, K. -Th., Briscoe, W. J., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Egiyan, H., Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jenkins, D., Jo, H. S., Kabir, M. L., Khanal, A., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Kripko, A., Kubarovsky, V., Lagerquist, V., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., Livingston, K., MacGregor, I. J. D., Marchand, D., Mascagna, V., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Richards, J., Ripani, M., Ritman, J., Rosner, G., Sabatié, F., Salgado, C., Schadmand, S., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Wei, X., Weinstein, L. B., Williams, R., Wishart, R., Wood, M. H., Zachariou, N., Zhao, Z. W., and Zurek, M.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

We report results of $\Lambda$ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014~GeV electron beam. These results represent the first measurements of the $\Lambda$ multiplicity ratio and transverse momentum broadening as a function of the energy fraction~($z$) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high~$z$~and~an enhancement at~low~$z$. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This indicates that the propagating entity interacts very strongly with the nuclear medium, which suggests that propagation of diquark configurations in the nuclear medium takes place at least part of the time, even at high~$z$. The trends of these results are qualitatively described by the Giessen Boltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity ratios. These observations will potentially open a new era of studies of the structure of the nucleon as well as of strange baryons., Comment: 14 pages, 6 figures

Published
2022
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16. First observation of correlations between spin and transverse momenta in back-to-back dihadron production at CLAS12

Author

Avakian, H., Hayward, T. B., Kotzinian, A., Armstrong, W. R., Atac, H., Gayoso, C. Ayerbe, Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Boiarinov, S., Bossù, F., Brinkman, K. T., Briscoe, W. J., Brooks, W. K., Bueltmann, S., Bulumulla, D., Burkert, V. D., Capobianco, R., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Forest, T., Gates, K., Gavalian, G., Gilyan, Y., Glazier, D. I., Golubenko, A. A., Gosta, G., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Hakobyan, H., Hattawy, M., Hauenstein, F., Heddle, D., Hobart, A., Holtrop, M., Hyde, C. E., Ilieva, Y., Ire, D. G., Isupov, E. L., Jo, H. S., Johnston, R., Joo, K., Kabir, M. L., Keller, D., Khachatryan, M., Khanal, A., Kim, A., Kim, W., Klimenko, V., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lagerquist, V., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., MacGregor, I . J . D., Marc, D., Mascagna, V., McKinnon, B., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Nguyen, D., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pogorelko, O., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Richards, J., Ripani, M., Ritman, J., Rossi, P., Sabatié, F., Salgado, C., Schmidt, A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Trotta, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D. P., Wei, X., Wishart, R., Wood, M. H., Zachariou, N., Zhao, Z. W., and Zurek, M.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction, where two hadrons are produced in opposite hemispheres along the z-axis in the center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed non-zero $\sin\Delta\phi$ modulations in $ep \rightarrow e'p\pi^+X$ events, where $\Delta\phi$ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unobserved leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization., Comment: 7 pages, 6 figures

Published
2022
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17. Alignment of the CLAS12 central hybrid tracker with a Kalman Filter

Author

Paul, S. J., Peck, A., Arratia, M., Gotra, Y., Ziegler, V., De Vita, R., Bossu, F., Defurne, M., Atac, H., Gayoso, C. Ayerbe, Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Boiarinov, S., Brinkmann, K. Th., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Capobianco, R., Carman, D. S., Carvajal, J. C., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Cole, P. L., Costantini, G., Angelo, A. D, Dashyan, N., Deur, A., Diehl, S., Djalali, C., Dupre, R., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Filippi, A., Gates, K., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Golubenko, A. A., Gosta, G., Gothe, R. W., Griffioen, K., Guidal, M., Hakobyan, H., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Johnston, R., Joo, K., Keller, D., Khachatryan, M., Khanal, A., Kim, A., Kim, W., Klimenko, V., Kripko, A., Lanza, L., Leali, M., Lenisa, P., Li, X., MacGregor, I. J. D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., McLauchlin, C., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Nguyen, D., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Pandey, P., Paolone, M., Paremuzyan, R., Pilleux, N., Pogorelko, O., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Reed, T., Ripani, M., Ritman, J., Sabatie, F., Schadmand, S., Schmidt, A., Shirokov, E. V., Shrestha, U., Simmerling, P., Spreafico, M., Sokhan, D., Sparveris, N., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Wishart, R., Wood, M. H., and Zachariou, N.

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

Several factors can contribute to the difficulty of aligning the sensors of tracking detectors, including a large number of modules, multiple types of detector technologies, and non-linear strip patterns on the sensors. All three of these factors apply to the CLAS12 CVT, which is a hybrid detector consisting of planar silicon sensors with non-parallel strips, and cylindrical micromegas sensors with longitudinal and arc-shaped strips located within a 5~T superconducting solenoid. To align this detector, we used the Kalman Alignment Algorithm, which accounts for correlations between the alignment parameters without requiring the time-consuming inversion of large matrices. This is the first time that this algorithm has been adapted for use with hybrid technologies, non-parallel strips, and curved sensors. We present the results for the first alignment of the CLAS12 CVT using straight tracks from cosmic rays and from a target with the magnetic field turned off. After running this procedure, we achieved alignment at the level of 10~$\mu$m, and the widths of the residual spectra were greatly reduced. These results attest to the flexibility of this algorithm and its applicability to future use in the CLAS12 CVT and other hybrid or curved trackers, such as those proposed for the future Electron-Ion Collider.

Published
2022
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18. Observation of azimuth-dependent suppression of hadron pairs in electron scattering off nuclei

Author

Paul, S. J., Moran, S., Arratia, M., Alaoui, A. El, Hakobyan, H., Brooks, W., Amaryan, M. J., Armstrong, W. R., Atac, H., Baashen, L., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Bossu, F., Boiarinov, S., Brinkmann, K. Th., Briscoe, W. J., Bulumulla, D., Burkert, V. D., Capobianco, R., Carman, D. S., Celentano, A., Chesnokov, V., Chetry, T., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Fassi, L. El, Eugenio, P., Fegan, S., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Golubenko, A. A., Gosta, G., Gothe, R. W., Griffioen, K. A., Guidal, M., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Johnston, R., Joo, K., Joosten, S., Keller, D., Khanal, A., Khandaker, M., Kim, W., Kripko, A., Kubarovsky, V., Lagerquist, V., Lanza, L., Leali, M., Lee, S., Lenisa, P., Li, X., Livingston, K., MacGregor, I. J. D., Marchand, D., Mascagna, V., McKinnon, B., Meziani, Z. E., Migliorati, S., Milner, R. G., Mineeva, T., Mirazita, M., Mokeev, V. I., Moran, P., Camacho, C. Munoz, Neupane, K., Nguyen, D., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pilleux, N., Pocanic, D., Pogorelko, O., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Ripani, M., Rosner, G., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Wei, X., Wishart, R., Wood, M. H., Zachariou, N., Zhao, Z. W., Ziegler, V., and Zurek, M.

Subjects
Nuclear Experiment
Abstract

We present the first measurement of di-hadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the GiBUU model, which suggests that hadrons form near the nuclear surface and undergo multiple-scattering in nuclei. These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei, Comment: 6 pages, 4 figures

Published
2022
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19. A new direct detection electron scattering experiment to search for the X17 particle

Author

Dutta, D, Gao, H, Gasparian, A, Hague, TJ, Liyanage, N, Paremuzyan, R, Peng, C, Xiong, W, Achenbach, P, Ahmidouch, A, Ali, S, Avakian, H, Ayerbe-Gayoso, C, Bai, X, Battaglieri, M, Bhatt, H, Bianconi, A, Boyd, J, Byer, D, Cole, PL, Costantini, G, Davis, S, Napoli, M De, Vita, R De, Devkota, B, Dharmasena, B, Dunne, J, Fassi, L El, Gamage, V, Gan, L, Gnanvo, K, Gosta, G, Higinbotham, D, Howell, C, Jeffas, S, Jian, S, Karki, A, Karki, B, Khachatryan, V, Khandaker, M, Kubarovsky, V, Larin, I, Leali, M, Mascagna, V, Matousek, G, Migliorati, S, Miskimen, R, Mohanmurthy, P, Nguyen, H, Pasyuk, E, Rathnayake, A, West, J Rittenhouse, Shahinyan, A, Smith, A, Stepanyan, S, Nieuwenhuizen, E van, Venturelli, L, Yu, B, Zhao, Z, and Zhou, J

Subjects
nucl-ex
Abstract

A new electron scattering experiment (E12-21-003) to verify and understandthe nature of hidden sector particles, with particular emphasis on theso-called X17 particle, has been approved at Jefferson Lab. The search forthese particles is motivated by new hidden sector models introduced to accountfor a variety of experimental and observational puzzles: excess in $e^+e^-$pairs observed in multiple nuclear transitions, the 4.2$\sigma$ disagreementbetween experiments and the standard model prediction for the muon anomalousmagnetic moment, and the small-scale structure puzzle in cosmologicalsimulations. The aforementioned X17 particle has been hypothesized to accountfor the excess in $e^+e^-$ pairs observed from the $^8$Be M1, $^4$He M0, and,most recently, $^{12}$C E1 nuclear transitions to their ground states observedby the ATOMKI group. This experiment will use a high resolution electromagneticcalorimeter to search for or set new limits on the production rate of the X17and other hidden sector particles in the $3 - 60$ MeV mass range via their$e^+e^-$ decay (or $\gamma\gamma$ decay with limited tracking). In thesemodels, the $1 - 100$ MeV mass range is particularly well-motivated and thelower part of this range still remains unexplored. Our proposed directdetection experiment will use a magnetic-spectrometer-free setup (the PRadapparatus) to detect all three final state particles in the visible decay of ahidden sector particle for an effective control of the background and willcover the proposed mass range in a single setting. The use of thewell-demonstrated PRad setup allows for an essentially ready-to-run anduniquely cost-effective search for hidden sector particles in the $3 - 60$ MeVmass range with a sensitivity of 8.9$\times$10$^{-8}$ - 5.8$\times$10$^{-9}$ to$\epsilon^2$, the square of the kinetic mixing interaction constant betweenhidden and visible sectors.

Published
2023

20. Upgrade of ASACUSA's Antihydrogen Detector

Author

Kraxberger, V., Amsler, C., Breuker, H., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Hunter, E. D., Killian, C., Kletzl, V., Kuroda, N., Lanz, A., Leali, M., Mäckel, V., Maero, G., Malbrunot, C., Mascagna, V., Matsuda, Y., Migliorati, S., Murtagh, D. J., Nagata, Y., Nanda, A., Nowak, L., Pasino, E., Romé, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., Venturelli, L., Weiser, A., Widmann, E., Wolz, T., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Instrumentation and Detectors, Nuclear Experiment
Abstract

The goal of the ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) CUSP experiment at CERN's Antiproton Decelerator is to measure the ground state hyperfine splitting of antihydrogen in order to test whether CPT invariance is broken. The ASACUSA hodoscope is a detector consisting of two layers of 32 plastic scintillator bars individually read out by two serially connected silicon photo multipliers (SiPMs) on each end. Two additional layers for position resolution along the beam axis were scintillator fibres, which will now be replaced by scintillating tiles placed onto the existing bars and also read out by SiPMs. If the antiproton of antihydrogen annihilates in the center of the hodoscope, particles (mostly pions) are produced and travel through the various layers of the detector and produce signals. The hodoscope was successfully used during the last data taking period at CERN. The necessary time resolution to discriminate between particles travelling through the detector from outside and particles produced in the center of the detector was achieved by the use of waveform digitisers and software constant fraction discrimination. The disadvantage of this readout scheme was the slow readout speed, which was improved by two orders of magnitude. This was done by omitting the digitisers and replacing them with TDCs reading out the digital time-over-threshold (ToT) signal using leading edge discrimination., Comment: Submitted to VCI2022 Proceedings in NIM A

Published
2022
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21. Exclusive $\pi^{-}$ Electroproduction off the Neutron in Deuterium in the Resonance Region

Author

Tian, Y., Gothe, R. W., Mokeev, V. I., Hollis, G., Amaryan, M. J., Armstrong, W. R., Atac, H., Avakian, H., Barion, L., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A., Bossù, F., Boiarinov, S., Bondì, M., Brinkmann, K. T., Briscoe, W. J., Bueltmann, S., Bulumulla, D., Burkert, V. D., Capobianco, R., Carman, D. S., Carvajal, J. C., Celentano, A., Chesnokov, V., Chetry, T., Ciullo, G., Clash, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Gavalian, G., Gilfoyle, G. P., Girod, F. X., Golubenko, A. A., Gosta, G., Griffioen, K., Guidal, M., Hakobyan, H., Hattawy, M., Hayward, T. B., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khanal, A., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Kripko, A., Kubarovsky, V., Lagerquist, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. . J . D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., Migliorati, S., Mineeva, T., Mirazita, M., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Newton, J., Niccolai, S., Nicol, M., Niculescu, G., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Počanić, D., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Reed, T., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Sabatié, F., Salgado, C., Schadmand, S., Schmidt, A., Schumacher, R. A., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wood, M. H., Yale, B., Zachariou, N., and Zhang, J.

Subjects
Nuclear Experiment
Abstract

New results for the exclusive and quasi-free cross sections off neutrons bound in deuterium ${\gamma}_vn(p) \rightarrow p{\pi}^{-} (p)$ are presented over a wide final state hadron angle range with a kinematic coverage of the invariant mass ($W$) up to 1.825 GeV and the virtual photon four-momentum transfer squared ($Q^{2}$) from 0.4 to 1.0 GeV$^2$. The exclusive structure functions were extracted and their Legendre moments were obtained. Final-state-interaction contributions have been kinematically separated from the extracted quasi-free cross sections off bound neutrons solely based on the analysis of the experimental data. These new results will serve as long-awaited input for phenomenological analyses to extract the $Q^{2}$ evolution of previously unavailable $n \to N^{*}$ electroexcitation amplitudes and to improve state-of-the-art models of neutrino scattering off nuclei by augmenting the already available results from free protons., Comment: The author list has been updated

Published
2022
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22. Cyclotron cooling to cryogenic temperature in a Penning-Malmberg trap with a large solid angle acceptance

Author

Amsler, C., Breuker, H., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Hunter, E. D., Killian, C., Kletzl, V., Kraxberger, V., Kuroda, N., Lanz, A., Leali, M., Mäckel, V., Maero, G., Malbrunot, C., Mascagna, V., Matsuda, Y., Migliorati, S., Murtagh, D. J., Nagata, Y., Nanda, A., Nowak, L., Pasino, E., Romé, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., Venturelli, L., Weiser, A., Widmann, E., Wolz, T., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Plasma Physics
Abstract

Magnetized nonneutral plasma composed of electrons or positrons couples to the local microwave environment via cyclotron radiation. The equilibrium plasma temperature depends on the microwave energy density near the cyclotron frequency. Fine copper meshes and cryogenic microwave absorbing material were used to lower the effective temperature of the radiation environment in ASACUSA's Cusp trap, resulting in significantly reduced plasma temperature.

Published
2022

23. Beam-Recoil Transferred Polarization in $K^+Y$ Electroproduction in the Nucleon Resonance Region with CLAS12

Author

Carman, D. S., D'Angelo, A., Lanza, L., Mokeev, V. I., Adhikari, K. P., Amaryan, M. J., Armstrong, W. R., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benkel, B., Bianconi, A., Biselli, A. S., Bondi, M., Boiarinov, S., Bossu, F., Briscoe, W. J., Bueltmann, S., Bulumulla, D., Burkert, V. D., Capobianco, R., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gothe, R. W., Gotra, Y., Griffioen, K. A., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Hayward, T. B., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Keller, D., Khanal, A., Kim, A., Kim, W., Klimenko, V., Kripko, A., Kubarovsky, V., Leali, M., Lee, S., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Marsicano, L., Mascagna, V., Mayer, M., McKinnon, B., Migliorati, S., Mineeva, T., Mirazita, M., Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Newton, J., Niccolai, S., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Pilleux, N., Pogorelko, O., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Ripani, M., Ritman, J., Rizzo, A., Rossi, P., Sabatie, F., Salgado, C., Schmidt, A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyler, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wishart, R., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., and Ziegler, V.

Subjects
Nuclear Experiment
Abstract

Beam-recoil transferred polarizations for the exclusive electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ final states from an unpolarized proton target have been measured using the CLAS12 spectrometer at Jefferson Laboratory. The measurements at beam energies of 6.535~GeV and 7.546~GeV span the range of four-momentum transfer $Q^2$ from 0.3 to 4.5~GeV$^2$ and invariant energy $W$ from 1.6 to 2.4~GeV, while covering the full center-of-mass angular range of the $K^+$. These new data extend the existing hyperon polarization data from CLAS in a similar kinematic range but from a significantly larger dataset. They represent an important addition to the world data, allowing for better exploration of the reaction mechanism in strangeness production processes, for further understanding of the spectrum and structure of excited nucleon states, and for improved insight into the strong interaction in the regime of non-perturbative dynamics., Comment: 25 pages, 22 figures, 4 tables

Published
2022
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24. Minimizing plasma temperature for antimatter mixing experiments

Author

Hunter, E. D., Amsler, C., Breuker, H., Chesnevskaya, S., Costantini, G., Ferragut, R., Giammarchi, M., Gligorova, A., Gosta, G., Higaki, H., Kanai, Y., Killian, C., Kletzl, V., Kraxberger, V., Kuroda, N., Lanz, A., Leali, M., Mäckel, V., Maero, G., Malbrunot, C., Mascagna, V., Matsuda, Y., Migliorati, S., Murtagh, D. J., Nagata, Y., Nanda, A., Nowak, L., Pasino, E., Romé, M., Simon, M. C., Tajima, M., Toso, V., Ulmer, S., Uggerhøj, U., Venturelli, L., Weiser, A., Widmann, E., Wolz, T., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Plasma Physics
Abstract

The ASACUSA collaboration produces a beam of antihydrogen atoms by mixing pure positron and antiproton plasmas in a strong magnetic field with a double cusp geometry. The positrons cool via cyclotron radiation inside the cryogenic trap. Low positron temperature is essential for increasing the fraction of antihydrogen atoms which reach the ground state prior to exiting the trap. Many experimental groups observe that such plasmas reach equilibrium at a temperature well above the temperature of the surrounding electrodes. This problem is typically attributed to electronic noise and plasma expansion, which heat the plasma. The present work reports anomalous heating far beyond what can be attributed to those two sources. The heating seems to be a result of the axially open trap geometry, which couples the plasma to the external (300 K) environment via microwave radiation., Comment: Proceedings of the Exotic Atoms (EXA) Conference, Vienna, 2021

Published
2022
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25. Polarized Structure Function $\sigma_{LT'}$ from $\pi^0 p$ Electroproduction Data in the Resonance Region at $0.4$ GeV$^2 < Q^2 < 1.0$ GeV$^2$

Author

Isupov, E. L., Burkert, V. D., Golubenko, A. A., Joo, K., Markov, N. S., Mokeev, V. I., Smith, L. C., Armstrong, W. R., Atac, H., Avakian, H., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Bossù, F., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Capobianco, R. A., Carman, D. S., Carvajal, J. C., Chatagnon, P., Chesnokov, V., Ciullo, G., Cole, P. L., Clary, B. A., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Gavalian, G., Gilfoyle, G. P., Glazier, D. I., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Illari, I., Ireland, D. G., Jenkins, D., Jo, H. S., Keller, D., Khanal, A., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Klimenko, V., Kripko, A., Kubarovsky, V., Lagerquist, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., Meziani, Z. E., Migliorati, S., Mineeva, T., Mirazita, M., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Niccolai, S., O'Connell, T., Osipenko, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Phelps, W., Pilleux, N., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Ripani, M., Ritman, J., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Simmerling, P., Sokhan, D., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D., Wei, K., Wei, X., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., and Ziegler, V.

Subjects
Nuclear Experiment
Abstract

The first results on the $\sigma_{LT'}$ structure function in exclusive $\pi^0p$ electroproduction at invariant masses of the final state of 1.5 GeV $<$ $W$ $<$ 1.8 GeV and in the range of photon virtualities 0.4 GeV$^2 < Q^2 < 1.0$ GeV$^2$ were obtained from data on beam spin asymmetries and differential cross sections measured with the CLAS detector at Jefferson Lab. The Legendre moments determined from the $\sigma_{LT'}$ structure function have demonstrated sensitivity to the contributions from the nucleon resonances in the second and third resonance regions. These new data on the beam spin asymmetries in $\pi^0p$ electroproduction extend the opportunities for the extraction of the nucleon resonance electroexcitation amplitudes in the mass range above 1.6 GeV., Comment: 7 pages, 3 figures

Published
2021
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26. Measurement of charged-pion production in deep-inelastic scattering off nuclei with the CLAS detector

Author

Moran, S., Dupre, R., Hakobyan, H., Arratia, M., Brooks, W. K., Borquez, A., Alaoui, A. El, Fassi, L. El, Hafidi, K., Mendez, R., Mineeva, T., Paul, S. J., Amaryan, M. J., Angelini, Giovanni, Armstrong, Whitney R., Atac, H., Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, Fatiha, Bianconi, A., Biondo, L., Biselli, A. S., Bossu, F., Boiarinov, S., Briscoe, W. J., Bulumulla, D., Burkert, V. D., Carman, D. S., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Egiyan, H., Elouadrhiri, L., Eugenio, P., Fersch, R., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Golubenko, A. A., Gothe, R. W., Griffioen, K. A., Guidal, M., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Keller, D., Khanal, A., Khandaker, M., Kim, W., Klein, F. J., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J . D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Mirazita, M., Mokeev, V., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Niccolai, S., Niculescu, G., O'Connell, T. R., Osipenko, M., Ostrovidov, A. I., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, Trevor, Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D. P., Wei, Kevin, Wei, X., Weinstein, L. B., Wishart, R., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Background: Energetic quarks in nuclear DIS propagate through the nuclear medium. Processes that are believed to occur inside nuclei include quark energy loss through medium-stimulated gluon bremsstrahlung and intra-nuclear interactions of forming hadrons. More data are required to gain a more complete understanding of these effects. Purpose: To test the theoretical models of parton transport and hadron formation, we compared their predictions for the nuclear and kinematic dependence of pion production in nuclei. Methods: We have measured charged-pion production in semi-inclusive DIS off D, C, Fe, and Pb using the CLAS detector and the CEBAF 5.014 GeV electron beam. We report results on the nuclear-to-deuterium multiplicity ratio for $\pi^{+}$ and $\pi^{-}$ as a function of energy transfer, four-momentum transfer, and pion energy fraction or transverse momentum - the first three-dimensional study of its kind. Results: The $\pi^{+}$ multiplicity ratio is found to depend strongly on the pion fractional energy $z$, and reaches minimum values of $0.67\pm0.03$, $0.43\pm0.02$, and $0.27\pm0.01$ for the C, Fe, and Pb targets, respectively. The $z$ dependences of the multiplicity ratios for $\pi^{+}$ and $\pi^{-}$ are equal within uncertainties for C and Fe targets but show differences at the level of 10$\%$ for the Pb-target data. The results are qualitatively described by the GiBUU transport model, as well as with a model based on hadron absorption, but are in tension with calculations based on nuclear fragmentation functions. Conclusions: These precise results will strongly constrain the kinematic and flavor dependence of nuclear effects in hadron production, probing an unexplored kinematic region. They will help to reveal how the nucleus reacts to a fast quark, thereby shedding light on its color structure, transport properties, and on the mechanisms of the hadronization process., Comment: 22 pages, 5 figures, 12 tables

Published
2021
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27. A Direct Detection Search for Hidden Sector New Particles in the 3-60 MeV Mass Range

Author

Ahmidouch, A., Davis, S., Gasparian, A., Hague, T. J., Mtingwa, S., Pedroni, R., Ayerbe-Gayoso, C., Bhatt, H., Devkota, B., Dunne, J., Dutta, D., Fassi, L. El, Karki, A., Mohanmurthy, P., Peng, C., Ali, S., Bai, X., Boyd, J., Dharmasena, B., Gamage, V., Gnanvo, K., Jeffas, S., Jian, S., Liyanage, N., Nguyen, H., Rathnayake, A., Khandaker, M., Byer, D., Gao, H., Howell, C., Karki, B., Khachatryan, V., Matousek, G., van Nieuwenhuizen, E., Smith, A., Yu, B., Zhao, Z., Zhou, J., Shahinyan, A., Higinbotham, D., Kubarovsky, V., Paremuzyan, R., Pasyuk, E., Stepanyan, S., Avakian, H., Battaglieri, M., De Vita, R., Bianconi, A., Constantini, G., Gosta, G., Leali, M., Migliorati, S., Venturelli, L., Mascagna, V., De Napoli, M., Larin, I., Miskimen, R., Cole, P., Xiong, W., and West, J. Rittenhouse

Subjects
Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract

In our quest to understand the nature of dark matter and discover its non-gravitational interactions with ordinary matter, we propose an experiment using a \pbo ~calorimeter to search for or set new limits on the production rate of i) hidden sector particles in the $3 - 60$ MeV mass range via their $e^+e^-$ decay (or $\gamma\gamma$ decay with limited tracking), and ii) the hypothetical X17 particle, claimed in multiple recent experiments. The search for these particles is motivated by new hidden sector models and dark matter candidates introduced to account for a variety of experimental and observational puzzles: the small-scale structure puzzle in cosmological simulations, anomalies such as the 4.2$\sigma$ disagreement between experiments and the standard model prediction for the muon anomalous magnetic moment, and the excess of $e^+e^-$ pairs from the $^8$Be M1 and $^4$He nuclear transitions to their ground states observed by the ATOMKI group. In these models, the $1 - 100$ MeV mass range is particularly well-motivated and the lower part of this range still remains unexplored. Our proposed direct detection experiment will use a magnetic-spectrometer-free setup (the PRad apparatus) to detect all three final state particles in the visible decay of a hidden sector particle allowing for an effective control of the background and will cover the proposed mass range in a single setting. The use of the well-demonstrated PRad setup allows for an essentially ready-to-run and uniquely cost-effective search for hidden sector particles in the $3 - 60$ MeV mass range with a sensitivity of 8.9$\times$10$^{-8}$ - 5.8$\times$10$^{-9}$ to $\epsilon^2$, the square of the kinetic mixing interaction constant between hidden and visible sectors. This updated proposal includes our response to the PAC49 comments., Comment: 47 pages, 44 Figures. JLab PAC50 Proposal

Published
2021

28. First-time measurement of Timelike Compton Scattering

Author

Chatagnon, P., Niccolai, S., Stepanyan, S., Amaryan, M. J., Angelini, G., Armstrong, W. R., Atac, H., Gayoso, C. Ayerbe, Baltzell, N. A., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Bossù, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Caudron, M., Celentano, A., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., Defurne, M., De Vita, R., Deur, A., Diehl, S., Djalali, C., Dupré, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Fersch, R., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Guo, L., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Hyde, C. E., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Kabir, M. L., Keller, D., Khachatryan, G., Khanal, A., Kim, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lee, S., Lenisa, P., Livingston, K., MacGregor, I . J . D., Marchand, D., Marsicano, L., Mascagna, V., McKinnon, B., McLauchlin, C., Migliorati, S., Mirazita, M., Mokeev, V., Montgomery, R. A., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., O'Connell, T. R., Osipenko, M., Ouillon, M., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Raue, B. A., Reed, T., Ripani, M., Rizzo, A., Rossi, P., Rowley, J., Sabatié, F., Schmidt, A., Segarra, E. P., Sharabian, Y. G., Shirokov, E. V., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I. I., Strauch, S., Tyler, N., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wishart, R., Yale, B., Zachariou, N., Zhang, J., Zhao, Z. W., and Collaboration, the CLAS

Subjects
High Energy Physics - Experiment
Abstract

We present the first measurement of the Timelike Compton Scattering process, $\gamma p\to p^\prime \gamma^* (\gamma^*\to e^+e^-) $, obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities $2.25

Published
2021
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29. Improved $\Lambda p$ Elastic Scattering Cross Sections Between 0.9 and 2.0 GeV/c and Connections to the Neutron Star Equation of State

Author

CLAS Collaboration, Rowley, J., Compton, N., Djalali, C., Hicks, K., Price, J., Zachariou, N., Adhikari, K. P., Armstrong, W. R., Atac, H., Baashen, L., Barion, L., Bashkanov, M., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biondo, L., Biselli, A. S., Bondi, M., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fedotov, G., Fegan, S., Fersch, R., Filippi, A., Fradi, A., Gavalian, G., Girod, F. X., Glazier, D. I., Golubenko, A., Gothe, R. W., Griffioen, K., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Keller, D., Khanal, A., Khandaker, M., Kim, A., Korover, I., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., McCracken, M. E., McKinnon, B., McLauchlin, C., Meziani, Z. E., Migliorati, S., Mineeva, T., Mirazita, M., Mokeev, V., Munevar, E., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Niccolai, S., Niculescu, G., O'Connell, T. R., Osipenko, M., Ostrovidov, A. I., Pandey, P., Paolone, M., Pappalardo, L. L., Pasyuk, E., Pogorelko, O., Prok, Y., Reed, T., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I. I., Strauch, S., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D., Wei, K., Wei, X., Wishart, R., Wood, M. H., Yale, B., Yurov, M., Zhang, J., and Zhao, Z. W.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state (EOS). Yet, compared to other elastic scattering processes, there is very little data on $\Lambda$-$N$ scattering. This experiment utilized the CLAS detector to study the $\Lambda p \rightarrow \Lambda p$ elastic scattering cross section in the incident $\Lambda$ momentum range 0.9-2.0 GeV/c. This is the first data on this reaction in several decades. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments., Comment: 6 pages, 5 figures

Published
2021

30. Light dark matter searches with positrons

Author

Battaglieri, M., Bianconi, A., Bisio, P., Bondì, M., Celentano, A., Costantini, G., Cole, P. L., Darmé, L., De Vita, R., D'Angelo, A., De Napoli, M., Fassi, L. El, Kozhuharov, V., Italiano, A., Krnjaic, G., Lanza, L., Leali, M., Marsicano, L., Mascagna, V., Migliorati, S., Nardi, E., Raggi, M., Randazzo, N., Santopinto, E., Smith, E., Spreafico, M., Stepanyan, S., Ungaro, M., Valente, P., Venturelli, L., and Wood, M. H.

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

We discuss two complementary strategies to search for light dark matter (LDM) exploiting the positron beam possibly available in the future at Jefferson Laboratory. LDM is a new compelling hypothesis that identifies dark matter with new sub-GeV "hidden sector" states, neutral under standard model interactions and interacting with our world through a new force. Accelerator-based searches at the intensity frontier are uniquely suited to explore it. Thanks to the high intensity and the high energy of the CEBAF (Continuous Electron Beam Accelerator Facility) beam, and relying on a novel LDM production mechanism via positron annihilation on target atomic electrons, the proposed strategies will allow us to explore new regions in the LDM parameters space, thoroughly probing the LDM hypothesis as well as more general hidden sector scenarios., Comment: 11 pages, 8 figures. Prepared for submission in EPJA. This work supersedes the corresponding contribution in arXiv:2007.15081. Added aknowledgement to Jefferson Lab

Published
2021
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31. Beam charge asymmetries for deeply virtual Compton scattering off the proton

Author

Burkert, V., Elouadrhiri, L., Girod, F. -X., Niccolai, S., Voutier, E., Afanasev, A., Barion, L., Battaglieri, M., Bernauer, J. C., Bianconi, A., Capobianco, R., Caudron, M., Causse, L., Chatagnon, P., Chetry, T., Ciullo, G., Cole, P. L., Contalbrigo, M., Costantini, G., Defurne, M., Deur, A., Diehl, S., Dupré, R., Ehrhart, M., Fernando, I. P., Filippi, A., Forest, T., Grames, J., Gueye, P., Habet, S., Higinbotham, D., Hobart, A., Hyde, C. E., Joo, K., Kim, A., Klimenko, V., Ko, H. -S., Kubarovsky, V., Leali, M., Lenisa, P., Marchand, D., Mascagna, V., McCaughan, M., McKinnon, B., Movsisyan, A., Muñoz~Camacho, C., Pappalardo, L., Pasyuk, E., Poelker, M., Price, K., Raue, B., Shabestari, M., Santos, R., Sergeyeva, V., Strakovsky, I., Stoler, P., Venturelli, L., Zhao, S., Zhao, Z. W., and Collaboration, the CLAS

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The unpolarized and polarized Beam Char\-ge Asymmetries (BCAs) of the $\vv{e}^{\pm}p \to e^{\pm}p \gamma$ process off unpolarized hydrogen are discussed. The measurement of BCAs with the CLAS12 spectrometer at the Thomas Jefferson National Accelerator Facility, using polarized positron and electron beams at 10.6 GeV is investigated. This experimental configuration allows to measure azimuthal and $t$-dependences of the unpolarized and polarized BCAs over a large $(x_B,Q^2)$ phase space, providing a direct access to the real part of the Compton Form Factor (CFF) ${\mathcal H}$. Additionally, these measurements confront the Bethe-Heitler dominance hypothesis and eventual effects beyond leading twist. The impact of potential positron beam data on the determination of CFFs is also investigated within a local fitting approach of experimental observables. Positron data are shown to strongly reduce correlations between CFFs and consequently improve significantly the determination of $\Re {\rm e} [\mathcal{H}]$., Comment: 11 pages, 10 figures, Article part of the EPJA Topical Issue about "Positron beams and physics at Jefferson Lab". arXiv admin note: text overlap with arXiv:2007.15081

Published
2021
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32. Measurement of deeply virtual Compton scattering off Helium-4 with CLAS at Jefferson Lab

Author

Dupré, R., Hattawy, M., Baltzell, N. A., Bültmann, S., De Vita, R., Alaoui, A. El, Fassi, L. El, Egiyan, H., Girod, F. X., Guidal, M., Hafidi, K., Jenkins, D., Liuti, S., Perrin, Y., Stepanyan, S., Torayev, B., Voutier, E., Amaryan, M. J., Armstrong, W. R., Atac, H., Gayoso, C. Ayerbe, Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Bossù, F., Boiarinov, S., Briscoe, W. J., Bulumulla, D., Burkert, V., Carman, D. S., Carvajal, J. C., Caudron, M., Celentano, A., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clary, B. A., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., Defurne, M., Deur, A., Diehl, S., Djalali, C., Ehrhart, M., Elouadrhiri, L., Eugenio, P., Fegan, S., Filippi, A., Forest, T. A., Ghandilyan, Y., Gilfoyle, G. P., Gothe, R. W., Griffioen, K. A., Hakobyan, H., Hayward, T. B., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khachatryan, G., Khanal, A., Khandaker, M., Kim, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Livingston, K., Kabir, M. L., Leali, M., Lenisa, P., MacGregor, I. J. D., Marchand, D., Markov, N., Mascagna, V., Mayer, M., McKinnon, B., Mirazita, M., Mokeev, V. I., Neupane, K., Niccolai, S., O'Connell, T. R., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Payette, D., Phelps, W., Pivnyuk, N., Pogorelko, O., Poudel, J., Prok, Y., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rossi, P., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R., Sergeyeva, V., Sharabian, Y., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Strakovsky, I. I., Strauch, S., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Watts, D., Wei, K., Wei, X., Weinstein, L. B., Wishart, R., Wood, M. H., Yale, B., Zachariou, N., and Zhang, J.

Subjects
Nuclear Experiment
Abstract

We report on the measurement of the beam spin asymmetry in the deeply virtual Compton scattering off $^4$He using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab using a 6 GeV longitudinally polarized electron beam incident on a pressurized $^4$He gaseous target. We detail the method used to ensure the exclusivity of the measured reactions, in particular the upgrade of CLAS with a radial time projection chamber to detect the low-energy recoiling $^4$He nuclei and an inner calorimeter to extend the photon detection acceptance at forward angles. Our results confirm the theoretically predicted enhancement of the coherent ($e^4$He$~\to~e'$$^4$He$'\gamma'$) beam spin asymmetries compared to those observed on the free proton, while the incoherent ($e^4$He$~\to~e'$p$'\gamma'$X$'$) asymmetries exhibit a 30$\%$ suppression. From the coherent data, we were able to extract, in a model-independent way, the real and imaginary parts of the only $^4$He Compton form factor, $\cal H_A$, leading the way toward 3D imaging of the partonic structure of nuclei.

Published
2021
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33. Measurement of the proton spin structure at long distances

Author

Zheng, X., Deur, A., Kang, H., Kuhn, S. E., Ripani, M., Zhang, J., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Atac, H., Avakian, H., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Boiarinov, S., Bondi, M., Bossu, F., Bosted, P., Briscoe, W. J., Brock, J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carlin, C., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Chen, J. -P., Choi, S., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Diehl, S., Djalali, C., Drozdov, V. A., Dupre, R., Ehrhart, M., Alaoui, A. El, Elouadrhiri, L., Eugenio, P., Fedotov, G., Fegan, S., Fersch, R., Filippi, A., Forest, T. A., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. -X., Glazier, D. I., Gothe, R. W., Griffioen, K. A., Guidal, M., Guler, N., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holmstrom, T., Holtrop, M., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Joosten, S., Keith, C. D., Keller, D., Khanal, A., Khandaker, M., Kim, C. W., Kim, W., Klein, F. J., Kripko, A., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., livingston, K., Long, E., MacGregor, I. J. D., Markov, N., Marsicano, L., Mascagna, V., McKinnon, B., Meekins, D. G., Mineeva, T., Mirazita, M., Mokeev, V., Mullen, C., Nadel-Turonski, P., Neupane, K., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L., Park, K., Pasyuk, E., Phelps, W., Phillips, S. K., Pogorelko, O., Poudel, J., Prok, Y., Raue, B. A., Ritman, J., Rizzo, A., Rosner, G., Rossi, P., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Seely, M. L., Sharabian, Y. G., Shrestha, U., Sirca, S., Slifer, K., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Sulkosky, V., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Weinstein, L. B., Wood, M. H., Yale, B., Zachariou, N., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Measuring the spin structure of protons and neutrons tests our understanding of how they arise from quarks and gluons, the fundamental building blocks of nuclear matter. At long distances the coupling constant of the strong interaction becomes large, requiring non-perturbative methods to calculate quantum chromodynamics processes, such as lattice gauge theory or effective field theories. Here we report proton spin structure measurements from scattering a polarized electron beam off polarized protons. The spin-dependent cross-sections were measured at large distances, corresponding to the region of low momentum transfer squared between 0.012 and 1.0 GeV$^2$. This kinematic range provides unique tests of chiral effective field theory predictions. Our results show that a complete description of the nucleon spin remains elusive, and call for further theoretical works, e.g. in lattice quantum chromodynamics. Finally, our data extrapolated to the photon point agree with the Gerasimov-Drell-Hearn sum rule, a fundamental prediction of quantum field theory that relates the anomalous magnetic moment of the proton to its integrated spin-dependent cross-sections., Comment: Published version. 10 pages, 5 figures. 20 pages of supplementary material (data tables and a figure)

Published
2021
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34. Differential cross sections for {\Lambda}(1520) using photoproduction at CLAS

Author

Shrestha, U., Chetry, T., Djalali, C., Hicks, K., Nam, S. i., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Angelini, G., Atac, H., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Ciullo, G., Cole, P. L., Contalbrigo, M., Crede, V., De Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Dugger, M., Dupre, R., Egiyan, H., Ehrhart, M., Fassi, L. El, Eugenio, P., Fedotov, G., Fegan, S., Filippi, A., Gavalian, G., Ghandilyan, Y., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Holtrop, M., Huang, Q., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khanal, A., Khandaker, M., Kim, A., Kim, W., Klein, F. J., Kripko, A., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Marsicano, L., Mascagna, V., McCracken, M. E., McKinnon, B., Mokeev, V., Movsisyan, A., Munevar, E., Camacho, C. Munoz, Turonski, P. Nadel, Neupane, 5 K., Niccolai, S., Niculescu, G., O'Connell, T., Osipenko, M., Ostrovidov, A. I., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pivnyuk, N., Pogorelko, O., Poudel, J., Prok, Y., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
High Energy Physics - Experiment
Abstract

The reaction $\gamma p \rightarrow K^{+} \Lambda(1520)$ using photoproduction data from the CLAS $g12$ experiment at Jefferson Lab is studied. The decay of $\Lambda(1520)$ into two exclusive channels, $\Sigma^{+}\pi^{-}$ and $\Sigma^{-}\pi^{+}$, is studied from the detected $K^{+}$, $\pi^{+}$, and $\pi^{-}$ particles. A good agreement is established for the $\Lambda(1520)$ differential cross sections with the previous CLAS measurements. The differential cross sections as a function of CM angle are extended to higher photon energies. Newly added are the differential cross sections as a function of invariant 4-momentum transfer $t$, which is the natural variable to use for a theoretical model based on a Regge-exchange reaction mechanism. No new $N^*$ resonances decaying into the $K^+\Lambda(1520)$ final state are found., Comment: 16 pages, 12 figures, 2 tables

Published
2021
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35. Observation of Beam Spin Asymmetries in the Process $e p \rightarrow e \pi^{+}\pi^{-}X$ with CLAS12

Author

Hayward, T. B., Dilks, C., Vossen, A., Avakian, H., Adhikari, S., Angelini, G., Arratia, M., Atac, H., Gayoso, C. Ayerbe, Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondì, M., Bossù, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clary, B. A., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Dugger, M., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Forest, T. A., Gavalian, G., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Hicks, K., Hobart, A., Holtrop, M., Ireland, D. G., Isupov, E. L., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khachatryan, M., Khanal, A., Kim, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lee, S., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., McKinnon, B., Meziani, Z. E., Mirazita, M., Mokeev, V., Movsisyan, A, Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Nanda, S., Neupane, K., Niccolai, S., Niculescu, G., O'Connell, T. R., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Prok, Y., Raue, B. A., Ripani, M., Ritman, J., Rizzo, A., Rossi, P., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Segarra, E. P., Sharabian, Y. G., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Thornton, A., Tyler, N., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wood, M. H., Yale, B., Zachariou, N., and Zhang, J.

Subjects
High Energy Physics - Experiment
Abstract

The observation of beam spin asymmetries in two-pion production in semi-inclusive deep inelastic scattering off an unpolarized proton target is reported. The data presented here were taken in the fall of 2018 with the CLAS12 spectrometer using a 10.6 GeV longitudinally spin-polarized electron beam delivered by CEBAF at JLab. The measured asymmetries provide the first opportunity to extract the parton distribution function $e(x)$, which provides information about the interaction between gluons and quarks, in a collinear framework that offers cleaner access than previous measurements. The asymmetries also constitute the first ever signal sensitive to the helicity-dependent two-pion fragmentation function $G_1^\perp$. A clear sign change is observed around the $\rho$ mass that appears in model calculations and is indicative of the dependence of the produced pions on the helicity of the fragmenting quark., Comment: 6 pages, 5 figures

Published
2021
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36. Multidimensional, high precision measurements of beam single spin asymmetries in semi-inclusive $\pi^{+}$ electroproduction off protons in the valence region

Author

Diehl, S., Kim, A., Angelini, G., Joo, K., Adhikari, S., Amaryan, M., Arratia, M., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Baltzell, N. A., Barion, L., Bastami, S., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bondi, M., Bossu, F., Boiarinov, S., Brinkmann, K. -T., Briscoe, W. J., Brooks, W., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Clary, B. A., Cole, P. L., Contalbrigo, M., Costantini, G., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Dilks, C., Djalali, C., Dugger, M., Dupre, R., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Fegan, S., Filippi, A., Forest, T., Gavalian, G., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golubenko, A. A., Gothe, R. W., Gotra, Y., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Hyde, C. E., Ireland, D. G., Isupov, E. L., Jo, H. S., Johnston, R., Joosten, S., Keller, D., Khachatryan, M., Khanal, A., Kim, W., Kripko, A., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lee, S., Lenisa, P., Livingston, K., Lu, Z., MacGregor, I. J. D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., McKinnon, B., Meziani, Z. E., Milner, R. G., Mineeva, T., Mirazita, M., Mokeev, V., Moran, P., Movsisyan, A., Camacho, C. Munoz, Nadel-Turonski, P., Naidoo, P., Neupane, K., Niccolai, S., Niculescu, G., O'Connell, T. R., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Prok, Y., Prokudin, A., Raue, B. A., Ripani, M., Ritman, J., Rizzo, A., Roberts, C. D., Rossi, P., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Segarra, E. P., Sharabian, Y. G., Shrestha, U., Simmerling, P., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Tezgin, K., Thornton, A., Tyler, N., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D. P., Wei, K., Wei, X., Xu, S. -S., Yale, B., Zachariou, N., and Zhang, J.

Subjects
High Energy Physics - Experiment
Abstract

High precision measurements of the polarized electron beam-spin asymmetry in semi-inclusive deep inelastic scattering (SIDIS) from the proton have been performed using a 10.6~GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. We report here a high precision multidimensional study of single $\pi^{+}$ SIDIS data over a large kinematic range in Bjorken x, fractional energy and transverse momentum of the hadron as well as photon virtualities $Q^{2}$ ranging from $1-7\,$GeV$^{2}$. In particular, the structure function ratio $F^{\sin\phi}_{LU}/F_{UU}$ has been determined, where $F^{\sin\phi}_{LU}$ is a twist-3 quantity that can reveal novel aspects of emergent hadron mass and quark-gluon correlations within the nucleon. The data's impact on the evolving understanding of the underlying reaction mechanisms and their kinematic variation is explored using theoretical models for the different contributing transverse momentum dependent parton distribution functions.

Published
2021
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37. Photoproduction of the $f_2(1270)$ meson using the CLAS detector

Author

Carver, M., Celentano, A., Hicks, K., Marsicano, L., Mathieu, V., Pilloni, A., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Angelini, Giovanni, Atac, H., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, Fatiha, Bianconi, A., Biselli, A. S., Bondi, M., Bossù, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Clary, B. A., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De~Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., Ehrhart, M., El~Alaoui, A., El~Fassi, L., Eugenio, P., Fedotov, G., Fegan, S., Filippi, A., Gavalian, G., Gevorgyan, N., Gilfoyle, G. P., Girod, F. X., Gothe, R. W., Griffioen, K. A., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Holtrop, M., Huang, Q., Hyde, C. E., Ilieva, Y., Ireland, D. G., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Joosten, S. ~, Keller, D., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Klein, F. J., Kripko, A., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Mascagna, V., McCracken, M. E., McKinnon, B., Meziani, Z. E., Mokeev, V., A~Movsisyan, Munevar, E., Munoz~Camacho, C., Nadel-Turonski, P., Neupane, K., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Prok, Y., Protopopescu, D., Ripani, M., Ritchie, B. G., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatié, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyler, N., Tyson, R., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Yale, B., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

The quark structure of the $f_2(1270)$ meson has, for many years, been assumed to be a pure quark-antiquark ($q\bar{q}$) resonance with quantum numbers $J^{PC} = 2^{++}$. Recently, it was proposed that the $f_2(1270)$ is a molecular state made from the attractive interaction of two $\rho$-mesons. Such a state would be expected to decay strongly to final states with charged pions, due to the dominant decay $\rho \to \pi^+ \pi^-$, whereas decay to two neutral pions would likely be suppressed. Here, we measure for the first time the reaction $\gamma p \to \pi^0 \pi^0 p$, using the CLAS detector at Jefferson Lab for incident beam energies between 3.6-5.4~GeV. Differential cross sections, $d\sigma / dt$, for $f_2(1270)$ photoproduction are extracted with good precision, due to low backgrounds, and are compared with theoretical calculations., Comment: 5 pages, 4 figures

Published
2020
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38. Beam spin asymmetry in semi-inclusive electroproduction of a hadron pair

Author

Mirazita, M., Avakian, H., Courtoy, A., Pisano, S., Adhikari, S., Amaryan, M. J., Angelini, G., Atac, H., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, Fatiha, Bianconi, A., Biselli, A. S., Bossu', F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clary, B., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fegan, S., Fersch, R., Filippi, A., Forest, T. A., Ghandilyan, Y., Gavalian, G., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Huang, Q., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Keller, D., Khanal, A., Khandaker, M., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I . J . D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., McKinnon, B., Milner, R. G., Mineeva, T., Mokeev, V., Mullen, C., Camacho, C. Munoz, Neupane, K., Niculescu, G., O'Connell, T., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pocanic, D., Pogorelko, O., Poudel, J., Prok, Y., Raue, B. A., Ripani, M., Ritman, J., Rizzo, A., Rossi, P., Sabatie', F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Vossen, A., Voutier, E., Watts, D., Wei, K., Wei, X., Wood, M. H., Yale, B., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
High Energy Physics - Experiment, Nuclear Experiment
Abstract

A first measurement of the longitudinal beam spin asymmetry ALU in the semi-inclusive electroproduction of pairs of charged pions is reported. ALU is a higher-twist observable and offers the cleanest access to the nucleon twist-3 parton distribution function e(x). Data have been collected in the Hall-B at Jefferson Lab by impinging a 5.498 GeV electron beam on a liquid-hydrogen target, and reconstructing the scattered electron and the pion pair with the CLAS detector. One-dimensional projections of the sin(phiR) moments of ALU are extracted for the kinematic variables of interest in the valence quark region. The understanding of di-hadron production is essential for the interpretation of observables in single hadron production in semi-inclusive DIS, and pioneering measurements of single spin asymmetries in di-hadron production open a new avenue in studies of QCD dynamics.

Published
2020
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39. Measurement of the Principal Quantum Number Distribution in a Beam of Antihydrogen Atoms

Author

Kolbinger, B., Amsler, C., Cuendis, S. Arguedas, Breuker, H., Capon, A., Costantini, G., Dupré, P., Fleck, M., Gligorova, A., Higaki, H., Kanai, Y., Kletzl, V., Kuroda, N., Lanz, A., Leali, M., Mäckel, V., Malbrunot, C., Mascagna, V., Massiczek, O., Matsuda, Y., Murtagh, D. J., Nagata, Y., Nanda, A., Nowak, L., Radics, B., Sauerzopf, C., Simon, M. C., Tajima, M., Torii, H. A., Uggerhøj, U., Ulmer, S., Venturelli, L., Weiser, A., Wiesinger, M., Widmann, E., Wolz, T., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Atomic Physics
Abstract

The ASACUSA (Atomic Spectroscopy And Collisions Using Slow Antiprotons) collaboration plans to measure the ground-state hyperfine splitting of antihydrogen in a beam at the CERN Antiproton Decelerator with initial relative precision of 10-6 or better, to test the fundamental CPT (combination of charge conjugation, parity transformation and time reversal) symmetry between matter and antimatter. This challenging goal requires a polarised antihydrogen beam with a sufficient number of antihydrogen atoms in the ground state. The first measurement of the quantum state distribution of antihydrogen atoms in a low magnetic field environment of a few mT is described. Furthermore, the data-driven machine learning analysis to identify antihydrogen events is discussed., Comment: 18 pages, 10 figures

Published
2020

40. Extraction of beam-spin asymmetries from the hard exclusive $\pi^{+}$ channel off protons in a wide range of kinematics

Author

Diehl, S., Joo, K., Kim, A., Avakian, H., Kroll, P., Park, K., Riser, D., Semenov-Tian-Shansky, K., Tezgin, K., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Angelini, G., Asryan, G., Atac, H., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Boss`u, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Bulumulla, D., Burkert, V. D., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Cole, P. L., Contalbrigo, M., Crede, V., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Dilks, C., Djalali, C., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Eugenio, P., Filippi, A., Forest, T. A., Ghandilyan, Y., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hakobyan, H., Harrison, N., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Joosten, S., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, C. W., Kim, W., Kubarovsky, V., Kuhn, S. E., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., McKinnon, B., Meziani, Z. E., Mineeva, T., Mirazita, M., Mokeev, V., Camacho, C. Munoz, Nadel-Turonski, P., Niculescu, G., Osipenko, M., Paolone, M., Pappalardo, L. L., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Raue, B. A., Ripani, M., Rizzo, A., Rossi, P., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.

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

We have measured beam-spin asymmetries to extract the $\sin\phi$ moment $A_{LU}^{\sin\phi}$ from the hard exclusive $\vec{e} p \to e^\prime n \pi^+$ reaction above the resonance region, for the first time with nearly full coverage from forward to backward angles in the center-of-mass. The $A_{LU}^{\sin\phi}$ moment has been measured up to 6.6 GeV$^{2}$ in $-t$, covering the kinematic regimes of Generalized Parton Distributions (GPD) and baryon-to-meson Transition Distribution Amplitudes (TDA) at the same time. The experimental results in very forward kinematics demonstrate the sensitivity to chiral-odd and chiral-even GPDs. In very backward kinematics where the TDA framework is applicable, we found $A_{LU}^{\sin\phi}$ to be negative, while a sign change was observed near 90$^\circ$ in the center-of-mass. The unique results presented in this paper will provide critical constraints to establish reaction mechanisms that can help to further develop the GPD and TDA frameworks.

Published
2020
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41. An experimental program with high duty-cycle polarized and unpolarized positron beams at Jefferson Lab

Author

Accardi, A., Afanasev, A., Albayrak, I., Ali, S. F., Amaryan, M., Annand, J. R. M., Arrington, J., Asaturyan, A., Atac, H., Avakian, H., Averett, T., Gayoso, C. Ayerbe, Bai, X., Barion, L., Battaglieri, M., Bellini, V., Beminiwattha, R., Benmokhtar, F., Berdnikov, V. V., Bernauer, J. C., Bertone, V., Bianconi, A., Biselli, A., Bisio, P., Blunden, P., Boer, M., Bondì, M., Brinkmann, K. -T., Briscoe, W. J., Burkert, V., Cao, T., Camsonne, A., Capobianco, R., Cardman, L., Carmignotto, M., Caudron, M., Causse, L., Celentano, A., Chatagnon, P., Chen, J. -P., Chetry, T., Ciullo, G., Cline, E., Cole, P. L., Contalbrigo, M., Costantini, G., D'Angelo, A., Darmé, L., Day, D., Defurne, M., De Napoli, M., Deur, A., De Vita, R., D'Hose, N., Diehl, S., Diefenthaler, M., Dongwi, B., Dupré, R., Dutrieux, H., Dutta, D., Ehrhart, M., Fassi, L. El, Elouadrhiri, L., Ent, R., Erler, J., Fernando, I. P., Filippi, A., Flay, D., Forest, T., Fuchey, E., Fucini, S., Furletova, Y., Gao, H., Gaskell, D., Gasparian, A., Gautam, T., Girod, F. -X., Gnanvo, K., Grames, J., Grauvoge, G. N., Gueye, P., Guidal, M., Habet, S., Hague, T. J., Hamilton, D. J., Hansen, O., Hasell, D., Hattawy, M., Higinbotham, D. W., Hobart, A., Horn, T., Hyde, C. E., Ibrahim, H., Ilyichev, A., Italiano, A., Joo, K., Joosten, S. J., Khachatryan, V., Kalantarians, N., Kalicy, G., Karky, B., Keller, D., Keppel, C., Kerver, M., Khandaker, M., Kim, A., Kim, J., King, P. M., Kinney, E., Klimenko, V., Ko, H. -S., Kohl, M., Kozhuharov, V., Kriesten, B. T., Krnjaic, G., Kubarovsky, V., Kutz, T., Lanza, L., Leali, M., Lenisa, P., Liyanage, N., Liu, Q., Liuti, S., Mammei, J., Mantry, S., Marchand, D., Markowitz, P., Marsicano, L., Mascagna, V., Mazouz, M., McCaughan, M., McKinnon, B., McNulty, D., Melnitchouk, W., Metz, A., Meziani, Z. -E., Migliorati, S., Mihovilovic, M., Milner, R., Mkrtchyan, A., Mkrtchyan, H., Movsisyan, A., Moutarde, H., Muhoza, M., Camacho, C. Muñoz, Murphy, J., Nadel-Turonski, P., Nardi, E., Nazeer, J., Niccolai, S., Niculescu, G., Novotny, R., Owens, J. F., Paolone, M., Pappalardo, L., Paremuzyan, R., Pasquini, B., Pasyuk, E., Patel, T., Pegg, I., Peng, C., Perera, D., Poelker, M., Price, K., Puckett, A. J. R., Raggi, M., Randazzo, N., Rashad, M. N. H., Rathnayake, M., Raue, B., Reimer, P. E., Rinaldi, M., Rizzo, A., Roblin, Y., Roche, J., Rondon-Aramayo, O., Sabatié, F., Salmè, G., Santopinto, E., Estrada, R. Santos, Sawatzky, B., Schmidt, A., Schweitzer, P., Scopetta, S., Sergeyeva, V., Shabestari, M., Shahinyan, A., Sharabian, Y., Širca, S., Smith, E. S., Sokhan, D., Somov, A., Sparveris, N., Spata, M., Spiesberger, H., Spreafico, M., Stepanyan, S., Stoler, P., Strakovsky, I., Suleiman, R., Suresh, M., Sznajder, P., Szumila-Vance, H., Tadevosyan, V., Tadepalli, A. S., Thomas, A. W., Tiefenback, M., Trotta, R., Ungaro, M., Valente, P., Vanderhaeghen, M., Venturelli, L., Voskanyan, H., Voutier, E., Wojtsekhowski, B., Wood, M. H., Wood, S., Xie, J., Xiong, W., Ye, Z., Yurov, M., Zaunick, H. -G., Zhamkochyan, S., Zhang, J., Zhang, S., Zhao, S., Zhao, Z. W., Zheng, X., Zhou, J., and Zorn, C.

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

Positron beams, both polarized and unpolarized, are identified as essential ingredients for the experimental programs at the next generation of lepton accelerators. In the context of the hadronic physics program at Jefferson Lab (JLab), positron beams are complementary, even essential, tools for a precise understanding of the electromagnetic structure of nucleons and nuclei, in both the elastic and deep-inelastic regimes. For instance, elastic scattering of polarized and unpolarized electrons and positrons from the nucleon enables a model independent determination of its electromagnetic form factors. Also, the deeply-virtual scattering of polarized and unpolarized electrons and positrons allows unambiguous separation of the different contributions to the cross section of the lepto-production of photons and of lepton-pairs, enabling an accurate determination of the nucleons and nuclei generalized parton distributions, and providing an access to the gravitational form factors. Furthermore, positron beams offer the possibility of alternative tests of the Standard Model of particle physics through the search of a dark photon, the precise measurement of electroweak couplings, and the investigation of charged lepton flavor violation. This document discusses the perspectives of an experimental program with high duty-cycle positron beams at JLab., Comment: 18 pages, 7 figures This version superseeds the previous version which scientific content was decomposed into several more elaborated articles. All of these articles will be collected in the EPJ A Topical Issue about "Positron beam and physics at Jefferson Lab (e+@Jlab)"

Published
2020
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42. Photoproduction of $\eta$ mesons off the proton for $1.2 < E_\gamma < 4.7$ GeV using CLAS at Jefferson Laboratory

Author

Hu, T., Akbar, Z., Crede, V., Adhikari, K. P., Adhikari, S., Amaryan, M. J., Angelini, G., Asryan, G., Atac, H., Gayoso, C. Ayerbe, Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossu, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Carvajal, J., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Clary, B. A., Cole, P. L., Contalbrigo, M., Cruz-Torres, R., D'Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Eugenio, P., Fedotov, G., Fersch, R., Filippi, A., Gavalian, G., Gilfoyle, G. P., Girod, F. X., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Hayward, T. B., Heddle, D., Hicks, K., Hobart, A., Holtrop, M., Ilieva, Y., Illari, I., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Joosten, S., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., Livingston, K., MacGregor, I. J. D., Marchand, D., Markov, N., Mascagna, V., McCracken, M. E., McKinnon, B., Meyer, C. A., Meziani, Z. E., Mineeva, T., Mokeev, V., Movsisyan, A., Munevar, E., Camacho, C. Munoz, Nadel-Turonski, P., Niccolai, S., Niculescu, G., O'Connell, T., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Phelps, W., Pogorelko, O., Poudel, J., Price, J. W., Prok, Y., Protopopescu, D., Raue, B. A., Ripani, M., Ritman, J., Rizzo, A., Rosner, G., Rowley, J., Sabatie, F., Salgado, C., Schmidt, A., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Skorodumina, Iu., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Watts, D. P., Wei, K., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., and Zhao, Z. W.

Subjects
Nuclear Experiment, High Energy Physics - Experiment
Abstract

Photoproduction cross sections are reported for the reaction $\gamma p\to p\eta$ using energy-tagged photons and the CLAS spectrometer at Jefferson Laboratory. The $\eta$ mesons are detected in their dominant charged decay mode, $\eta\to \pi^+\pi^-\pi^0$, and results on differential cross sections are presented for incident photon energies between 1.2 and 4.7 GeV. These new $\eta$ photoproduction data are consistent with earlier CLAS results but extend the energy range beyond the nucleon resonance region into the Regge regime. The normalized angular distributions are also compared with the experimental results from several other experiments, and with predictions of $\eta$ MAID\,2018 and the latest solution of the Bonn-Gatchina coupled-channel analysis. Differential cross sections $d\sigma/dt$ are presented for incident photon energies $E_\gamma > 2.9$ GeV ($W > 2.5$ GeV), and compared with predictions which are based on Regge trajectories exchange in the $t$-channel (Regge models). The data confirm the expected dominance of $\rho$, $\omega$ vector-meson exchange in an analysis by the Joint Physics Analysis Center., Comment: 24 pages, 22 figures

Published
2020
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43. Probing the core of the strong nuclear interaction

Author

Schmidt, A., Pybus, J. R., Weiss, R., Segarra, E. P., Hrnjic, A., Denniston, A., Hen, O., Piasetzky, E., Weinstein, L. B., Barnea, N., Strikman, M., Larionov, A., Higinbotham, D., Adhikari, S., Amaryan, M., Angelini, G., Asryan, G., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Baashen, L., Barion, L., Bashkanov, M., Battaglieri, M., Beck, A., Bedlinskiy, I., Benmokhtar, F., Bianconi, A., Biselli, A. S., Bossu, F., Biarinov, S., Briscoe, W. J., Brooks, W., Burkert, V. D., Cao, F., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Ciullo, G., Clark, L., Cohen, E., Cole, P. L., Contalbrigo, M., Crede, V., Cruz-Torres, R., D'Angelo, A., Dashyan, N., De Vita, R., De Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Duer, M., Dugger, M., Dupre, R., Egiyan, H., Ehrhart, M., Alaoui, A. El, Fassi, L. El, Eugenio, P., Filippi, A., Forest, T. A., Gavalian, G., Gilad, S., Gilfoyle, G. P., Giovanetti, K. L., Girod, F. X., Giuseppe, C., Glazier, D. I., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guo, L., Hafidi, K., Hakobyan, H., Hanretty, C., Harrison, N., Hattawy, M., Hauenstein, F., Hayward, T. B., Hicks, K., Holtrop, M., Ilieva, Y., Illari, I., Ireland, D., Ishkanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Joo, K., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, C. W., Kim, W., Klein, F. J., Korover, I., Kubarovsky, V., Lanza, L., Leali, M., Lenisa, P., MacGregor, I. J. D., Marchand, D., Markov, N., Marsicano, L., Mascagna, V., Beck, S. May-Tal, McKinnon, B., Mirazita, M., Mokeev, V., Camacho, C. Munoz, Mustapha, B., Nadel-Turonski, P., Nanda, S., Niccolai, S., Niculescu, G., Osipenko, M., Ostrovidov, A. I., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Patsyuk, M., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rosner, G., Rossi, P., Sabatie, F., Salgado, C., Schmookler, B., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Skorodumina, Iu., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Strakovsky, I. I., Strauch, S., Tan, J. A., Tyler, N., Ungaro, M., Venturelli, L., Voskanyan, H., Voutier, E., Wang, R., Watts, D. P., Wei, X., Wood, M. H., Zachariou, N., Zhang, J., Zhao, Z. W., and Zheng, X.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The strong nuclear interaction between nucleons (protons and neutrons) is the effective force that holds the atomic nucleus together. This force stems from fundamental interactions between quarks and gluons (the constituents of nucleons) that are described by the equations of Quantum Chromodynamics (QCD). However, as these equations cannot be solved directly, physicists resort to describing nuclear interactions using effective models that are well constrained at typical inter-nucleon distances in nuclei but not at shorter distances. This limits our ability to describe high-density nuclear matter such as in the cores of neutron stars. Here we use high-energy electron scattering measurements that isolate nucleon pairs in short-distance, high-momentum configurations thereby accessing a kinematical regime that has not been previously explored by experiments, corresponding to relative momenta above 400 MeV/c. As the relative momentum between two nucleons increases and their separation thereby decreases, we observe a transition from a spin-dependent tensor-force to a predominantly spin-independent scalar-force. These results demonstrate the power of using such measurements to study the nuclear interaction at short-distances and also support the use of point-like nucleons with two- and three-body effective interactions to describe nuclear systems up to densities several times higher than the central density of atomic nuclei., Comment: Total 26 pages, 13 figures. Main text: 8 pages, 3 figures. Methods section: 6 pages. Extended Data: 8 figures, 1 table. Supplementary Materials: 8 pages, 2 figures

Published
2020
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44. A Direct Detection Search for Hidden Sector New Particles in the 3-60 MeV Mass Range

Author

Ahmidouch, A, Davis, S, Gasparian, A, Hague, TJ, Mtingwa, S, Pedroni, R, Ayerbe-Gayoso, C, Bhatt, H, Devkota, B, Dunne, J, Dutta, D, Fassi, L El, Karki, A, Mohanmurthy, P, Peng, C, Ali, S, Bai, X, Boyd, J, Dharmasena, B, Gamage, V, Gnanvo, K, Jeffas, S, Jian, S, Liyanage, N, Nguyen, H, Rathnayake, A, Khandaker, M, Byer, D, Gao, H, Howell, C, Karki, B, Khachatryan, V, Matousek, G, Nieuwenhuizen, E van, Smith, A, Yu, B, Zhao, Z, Zhou, J, Shahinyan, A, Higinbotham, D, Kubarovsky, V, Paremuzyan, R, Pasyuk, E, Stepanyan, S, Avakian, H, Battaglieri, M, Vita, R De, Bianconi, A, Constantini, G, Gosta, G, Leali, M, Migliorati, S, Venturelli, L, Mascagna, V, Napoli, M De, Larin, I, Miskimen, R, Cole, P, Xiong, W, and West, J Rittenhouse

Subjects
nucl-ex, physics.ins-det
Abstract

In our quest to understand the nature of dark matter and discover itsnon-gravitational interactions with ordinary matter, we propose an experimentusing a \pbo ~calorimeter to search for or set new limits on the productionrate of i) hidden sector particles in the $3 - 60$ MeV mass range via their$e^+e^-$ decay (or $\gamma\gamma$ decay with limited tracking), and ii) thehypothetical X17 particle, claimed in multiple recent experiments. The searchfor these particles is motivated by new hidden sector models and dark mattercandidates introduced to account for a variety of experimental andobservational puzzles: the small-scale structure puzzle in cosmologicalsimulations, anomalies such as the 4.2$\sigma$ disagreement between experimentsand the standard model prediction for the muon anomalous magnetic moment, andthe excess of $e^+e^-$ pairs from the $^8$Be M1 and $^4$He nuclear transitionsto their ground states observed by the ATOMKI group. In these models, the $1 -100$ MeV mass range is particularly well-motivated and the lower part of thisrange still remains unexplored. Our proposed direct detection experiment willuse a magnetic-spectrometer-free setup (the PRad apparatus) to detect all threefinal state particles in the visible decay of a hidden sector particle allowingfor an effective control of the background and will cover the proposed massrange in a single setting. The use of the well-demonstrated PRad setup allowsfor an essentially ready-to-run and uniquely cost-effective search for hiddensector particles in the $3 - 60$ MeV mass range with a sensitivity of8.9$\times$10$^{-8}$ - 5.8$\times$10$^{-9}$ to $\epsilon^2$, the square of thekinetic mixing interaction constant between hidden and visible sectors. Thisupdated proposal includes our response to the PAC49 comments.

Published
2021

45. Exclusive $\bm{\pi^{0}p}$ electroproduction off protons in the resonance region at photon virtualities 0.4~GeV$\bm{^{2}}$ $\bm{\leq~ Q^{2} \leq~1}$~GeV$\bm{^{2}}$

Author

Markov, N., Joo, K., Burkert, V. D., Mokeev, V. I., Smith, L. C., Ungaro, M., Adhikari, S., Amaryan, M. J., Angelini, G., Atac, H., Avakian, H., Gayoso, C. Ayerbe, Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benmokhtar, F., Biselli, A. S., Bossù, F., Boiarinov, S., Briscoe, W. J., Brooks, W. K., Carman, D. S., Carvajal, J. C., Celentano, A., Chatagnon, P., Chetry, T., Cole, P. L., Contalbrigo, M., Crede, V., Ciullo, G., D'Angelo, A., Dashyan, N., De~Vita, R., De~Sanctis, E., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dupre, R., Ehrhart, M., El~Alaoui, A., El~Fassi, L., Eugenio, P., Evans, C., Filippi, A., Ghandilyan, Y., Girod, F. X., Golovatch, E., Gothe, R. W., Griffioen, K. A., Guidal, M., Hafidi, K., Hakobyan, H., Hattawy, M., Hayward, T. B., Hicks, K., Holtrop, M., Ilieva, Y., Ireland, D. G., Ishkhanov, B. S., Isupov, E. L., Jenkins, D., Jo, H. S., Keller, D., Khachatryan, M., Khanal, A., Khandaker, M., Kim, A., Kim, C. W., Kim, W., Klein, F. J., Kubarovsky, V., Lanza, L., Leali, M., Livingston, K., MacGregor, I . J . D., Marchand, D., Mascagna, V., McKinnon, B., Mineeva, T., Mirazita, M., Nadel-Turonski, P., Nanda, S., Niccolai, S., Niculescu, G., Osipenko, M., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Park, K., Pasyuk, E., Phelps, W., Pogorelko, O., Price, J. W., Prok, Y., Protopopescu, D., Ripani, M., Riser, D., Rizzo, A., Rowley, J., Sabatié, F., Salgado, C., Schumacher, R. A., Sharabian, Y. G., Shrestha, U., Sokhan, D., Soto, O., Sparveris, N., Stepanyan, S., Stoler, P., Strakovsky, I. I., Strauch, S., Taiuti, M., Tan, J. A., Tyler, N., Venturelli, L., Voskanyan, H., Voutier, E., Wang, R., Wei, X., Wood, M. H., and Zachariou, N.

Subjects
Nuclear Experiment
Abstract

The exclusive electroproduction process $ep \rightarrow e'p'\pi^{0}$ was measured in the range of photon virtualities $Q^{2} = 0.4 - 1.0$~GeV$^{2}$ and the invariant mass range of the $p\pi^{0}$ system of $W = 1.1 - 1.8$~GeV. These kinematics are covered in exclusive $\pi^{0}$ electroproduction off the proton with nearly complete angular coverage in the $p\pi^{0}$ center-of-mass system and with high statistical accuracy. Nearly 36000 cross section points were measured, and the structure functions $\sigma_T+\epsilon\sigma_L$, $\sigma_{LT}$, and $\sigma_{TT}$, were extracted via fitting the $\phi_{\pi^{0}}$ dependence of the cross section. A Legendre polynomial expansion analysis demonstrates the sensitivity of our data to high-lying $N^*$ and $\Delta^{*}$ resonances with $M~>~1.6$ GeV. As part of a broad effort to determine the electrocouplings of the $N^{*}$ and $\Delta^{*}$ resonances using both single- and double-pion electroproduction, this dataset is crucial for the reliable extraction of the high-lying resonance electrocouplings from the combined isospin analysis of the $N \pi$ and $\pi^{+}\pi^{-} p$ channels., Comment: 21 pages, 24 figures

Published
2019
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46. Measurement of the helicity asymmetry Eγ→p→→pπ0 for the Eγ→p→→pπ0 reaction in the resonance region: The CLAS Collaboration

Author

Kim, C. W., Zachariou, N., Bashkanov, M., Briscoe, W. J., Fegan, S., Kashevarov, V. L., Nikonov, K., Sarantsev, A., Schmidt, A., Strakovsky, I. I., Watts, D. P., Workman, R. L., Achenbach, P., Akbar, Z., Amaryan, M. J., Angelini, G., Armstrong, W. R., Atac, H., Baashen, L., Baltzell, N. A., Barion, L., Battaglieri, M., Bedlinskiy, I., Benkel, B., Benmokhtar, F., Benmouna, N., Bianconi, A., Biselli, A. S., Booth, W. A., Bossù, F., Boiarinov, S., Brinkmann, K. T., Brock, J., Bulumulla, D., Burkert, V. D., Cao, T., Carlin, C., Carman, D. S., Carvajal, J. C., Chatagnon, P., Chesnokov, V., Chetry, T., Ciullo, G., Clash, G., Cole, P. L., Contalbrigo, M., Becerra, O. Cortes, Costantini, G., Crede, V., D’Angelo, A., Dashyan, N., De Vita, R., Defurne, M., Deur, A., Diehl, S., Djalali, C., Dugger, M., Dupre, R., Egiyan, H., Alaoui, A. El, Fassi, L. El, Elouadrhiri, L., Eugenio, P., Filippi, A., Fogler, C., Gavalian, G., Gilfoyle, G. P., Golubenko, A. A., Gosta, G., Gothe, R. W., Griffioen, K. A., Hafidi, K., Hakobyan, H., Hattawy, M., Hauenstein, F., Hayward, T. B., Heddle, D., Hobart, A., Holtrop, M., Ilieva, Y., Illari, I., Ireland, D. G., Isupov, E. L., Iwamoto, H., Jenkins, D., Jo, H. S., Johnston, R., Joo, K., Joosten, S., Kageya, T., Keith, C. D., Keller, D., Khanal, A., Kim, A., Kim, W., Klein, F. J., Klimenko, V., Kripko, A., Kubarovsky, V., Lanza, L., Leali, M., Lee, S., Li, X., Livingston, K., MacGregor, I. J. D., Marchand, D., Mascagna, V., McKinnon, B., Migliorati, S., Milner, R. G., Mineeva, T., Mokeev, V., Camacho, C. Munoz, Nadel-Turonski, P., Neupane, K., Niccolai, S., Osipenko, M., Ostrovidov, A. I., Pandey, P., Paolone, M., Pappalardo, L. L., Paremuzyan, R., Pasyuk, E., Paul, S. J., Pilleux, N., Pokhrel, M., Poudel, J., Price, J. W., Prok, Y., Radic, A., Ramasubramanian, N., Ratliff, S., Reed, T., Richards, J., Ripani, M., Ritchie, B. G., Ritman, J., Rosner, G., Salgado, C., Schadmand, S., Schott, D., Schumacher, R. A., Scott, M. B. C., Seely, M. L., Seroka, E. M., Shirokov, E. V., Shrestha, U., Sokhan, D., Sparveris, N., Spreafico, M., Strauch, S., Tan, J., Tyson, R., Ungaro, M., Vallarino, S., Venturelli, L., Voskanyan, H., Voutier, E., Wei, X., Williams, R., Wishart, R., Wood, M. H., Yurov, M., Zhang, J., and Zurek, M.

Published
2023
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47. Antiproton beams with low energy spread for antihydrogen production

Author

Tajima, M., Kuroda, N., Amsler, C., Breuker, H., Evans, C., Fleck, M., Gligorova, A., Higaki, H., Kanai, Y., Kolbinger, B., Lanz, A., Leali, M., Mäckel, V., Malbrunot, C., Mascagna, V., Matsuda, Y., Murtagh, D., Nagata, Y., Nanda, A., Radics, B., Simon, M., Ulmer, S., Venturelli, L., Widmann, E., Wiesinger, M., and Yamazaki, Y.

Subjects
Physics - Instrumentation and Detectors, Physics - Accelerator Physics
Abstract

A low energy antiproton transport from the ASACUSA antiproton accumulation trap (MUSASHI trap) to the antihydrogen production trap (double cusp trap) is developed. The longitudinal antiproton energy spread after the transport line is 0.23 +- 0.02 eV, compared with 15 eV with a previous method used in 2012. This reduction is achieved by an adiabatic transport beamline with several pulse-driven coaxial coils. Antihydrogen atoms are synthesized by directly injecting the antiprotons into a positron plasma, resulting in the higher production rate., Comment: 10 pages, 9 figures

Published
2019
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48. A hydrogen beam to characterize the ASACUSA antihydrogen hyperfine spectrometer

Author

Malbrunot, C., Diermaier, M., Simon, M. C., Amsler, C., Cuendis, S. Arguedas, Breuker, H., Evans, C., Fleck, M., Kolbinger, B., Lanz, A., Leali, M., Maeckel, V., Mascagna, V., Massiczek, O., Matsuda, Y., Nagata, Y., Sauerzopf, C., Venturelli, L., Widmann, E., Wiesinger, M., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Atomic Physics
Abstract

The antihydrogen programme of the ASACUSA collaboration at the antiproton decelerator of CERN focuses on Rabi-type measurements of the ground-state hyperfine splitting of antihydrogen for a test of the combined Charge-Parity-Time symmetry. The spectroscopy apparatus consists of a microwave cavity to drive hyperfine transitions and a superconducting sextupole magnet for quantum state analysis via Stern-Gerlach separation. However, the small production rates of antihydrogen forestall comprehensive performance studies on the spectroscopy apparatus. For this purpose a hydrogen source and detector have been developed which in conjunction with ASACUSA's hyperfine spectroscopy equipment form a complete Rabi experiment. We report on the formation of a cooled, polarized, and time modulated beam of atomic hydrogen and its detection using a quadrupole mass spectrometer and a lock-in amplification scheme. In addition key features of ASACUSA's hyperfine spectroscopy apparatus are discussed.t

Published
2018
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49. Hyperfine spectroscopy of hydrogen and antihydrogen in ASACUSA

Author

Widmann, E., Amsler, C., Cuendis, S. Arguedas, Breuker, H., Diermaier, M., Dupré, P., Evans, C., Fleck, M., Gligorova, A., Higaki, H., Kanai, Y., Kolbinger, B., Kuroda, N., Leali, M., Leite, A. M. M., Mäckel, V., Malbrunot, C., Mascagna, V., Massiczek, O., Matsuda, Y., Murtagh, D. J., Nagata, Y., Nanda, A., Phan, D., Sauerzopf, C., Simon, M. C., Tajima, M., Spitzer, H., Strube, M., Ulmer, S., Venturelli, L., Wiesinger, M., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Atomic Physics
Abstract

The ASACUSA collaboration at the Antiproton Decelerator of CERN aims at a precise measurement of the antihydrogen ground-state hyperfine structure as a test of the fundamental CPT symmetry. A beam of antihydrogen atoms is formed in a CUSP trap, undergoes Rabi-type spectroscopy and is detected downstream in a dedicated antihydrogen detector. In parallel measurements using a polarized hydrogen beam are being performed to commission the spectroscopy apparatus and to perform measurements of parameters of the Standard Model Extension (SME). The current status of antihydrogen spectroscopy is reviewed and progress of ASACUSA is presented., Comment: Proceedings of the 7th International Syposium on Symmetries in Subatomic Physics SSP2018, Aachen (Germany), 10 - 15 Jun 2018. Corrected error in Fig. 1, updated caption, add titles to references

Published
2018
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50. The ASACUSA antihydrogen and hydrogen program : results and prospects

Author

Malbrunot, C., Amsler, C., Cuendi, S. Arguedas, Breuker, H., Dupre, P., Fleck, M., Higaki, H., Kanai, Y., Kobayashi, T., Kolbinger, B., Kuroda, N., Leali, M., Maeckel, V., Mascagna, V., Massiczek, O., Matsuda, Y., Nagata, Y., Simon, M. C., Spitzer, H., Tajima, M., Ulmer, S., Venturelli, L., Widmann, E., Wiesinger, M., Yamazaki, Y., and Zmeskal, J.

Subjects
Physics - Atomic Physics
Abstract

The goal of the ASACUSA-CUSP collaboration at the Antiproton Decelerator of CERN is to measure the ground-state hyperfine splitting of antihydrogen using an atomic spectroscopy beamline. A milestone was achieved in 2012 through the detection of 80 antihydrogen atoms 2.7 meters away from their production region. This was the first observation of "cold" antihydrogen atoms in a magnetic field free region. In parallel to the progress on the antihydrogen production, the spectroscopy beamline was tested with a source of hydrogen. This led to a measurement at a relative precision of 2.7x 10^(-9) which constitues the most precise measurement of the hydrogen hyperfine splitting in a beam. Further measurements with an upgraded hydrogen apparatus are motivated by CPT and Lorentz violation tests in the framework of the Standard Model Extension. Unlike for hydrogen, the antihydrogen experiment is complicated by the difficulty of synthesizing enough cold antiatoms in ground-state. The first antihydrogen quantum states scan at the entrance of the spectroscopy apparatus was realized in 2016 and is presented here. The prospects for a ppm measurement are also discussed., Comment: 16 pages

Published
2017
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