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DOE OSTI · 2438684

HighNESS conceptual design report: Volume II. The NNBAR experiment.

Abstract

A key aim of the HighNESS project for the European Spallation Source is to enable cutting-edge particle physics experiments. This volume presents a conceptual design report for the NNBAR experiment. NNBAR would exploit a new cold lower moderator to make the first search in over thirty years for free neutrons converting to anti-neutrons. The observation of such a baryon-number-violating signature would be of fundamental significance and tackle open questions in modern physics, including the origin of the matter-antimatter asymmetry. This report shows the design of the beamline, supermirror focusing system, magnetic and radiation shielding, and anti-neutron detector necessary for the experiment. A range of simulation programs are employed to quantify the performance of the experiment and show how background can be suppressed. For a search with full background suppression, a sensitivity improvement of three orders of magnitude is expected, as compared with the previous search. Civil engineering studies for the NNBAR beamline are also shown, as is a costing model for the experiment.

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Santoro, V., Abou El Kheir, O., Acharya, D., Akhyani, M., Andersen, K. H., Barrow, J., Bentley, P., Bernasconi, M., Bertelsen, M., Beßler, Y., Bianchi, A., Brooijmans, G., Broussard, L., Brys, T., Busi, M., Campi, D., Chambon, A., Chen, J., Czamler, V., Deen, P., DiJulio, D. D., Dian, E., Draskovits, L., Dunne, K., El Barbari, M., Ferreira, M. J., Fierlinger, P., Fröst, V. T., Folsom, B. T., Friman-Gayer, U., Gaye, A., Gorini, G., Gustafsson, A., Gutberlet, T., Happe, C., Han, X., Hartl, M., Holl, M., Jackson, A., Kemp, E., Kamyshkov, Y., Kittelmann, T., Klinkby, E. B., Kolevatov, R., Laporte, S. I., Lauritzen, B., Lejon, W., Linander, R., Lindroos, M., Marko, M., Márquez Damián, J. I., McClanahan, T. C., Meirose, B., Mezei, F., Michel, K., Milstead, D., Muhrer, G., Nepomuceno, A., Neshvizhevsky, V., Nilsson, T., Odén, U., Plivelic, T., Ramic, K., Rataj, B., Remec, I., Rizzi, N., Rogers, J., Rosenthal, E., Rosta, L., Rücker, U., Samothrakitis, S., Schreyer, A., Selknaes, J. R., Shuai, H., Silverstein, S., Snow, W. M., Strobl, M., Strothmann, M., Takibayev, A., Wagner, R., Willendrup, P., Xu, S., Yiu, S. C., Yngwe, L., Young, A. R., Wolke, M., Zakalek, P., Zavorka, L., Zanini, L., Zimmer, O.. 2024-05-03. HighNESS conceptual design report: Volume II. The NNBAR experiment.. https://doi.org/10.3233/jnr-230951

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