Hunting down the X17 boson at the CERN SPS

Autor: NA64 Collaboration, E. Depero, Yu. M. Andreev, D. Banerjee, J. Bernhard, V. E. Burtsev, N. Charitonidis, A. G. Chumakov, D. Cooke, P. Crivelli, A. V. Dermenev, S. V. Donskov, R. R. Dusaev, T. Enik, A. Feshchenko, V. N. Frolov, A. Gardikiotis, S. G. Gerassimov, S. Girod, S. N. Gninenko, M. Hösgen, V. A. Kachanov, A. E. Karneyeu, G. Kekelidze, B. Ketzer, D. V. Kirpichnikov, M. M. Kirsanov, V. N. Kolosov, I. V. Konorov, S. G. Kovalenko, V. A. Kramarenko, L. V. Kravchuk, N. V. Krasnikov, S. V. Kuleshov, V. E. Lyubovitskij, V. Lysan, V. A. Matveev, Yu. V. Mikhailov, L. Molina Bueno, D. V. Peshekhonov, V. A. Polyakov, B. Radics, R. Rojas, A. Rubbia, V. D. Samoylenko, D. Shchukin, H. Sieber, V. O. Tikhomirov, vI. Tlisova, D. A. Tlisov, A. N. Toropin, A. Yu. Trifonov, B. I. Vasilishin, G. Vasquez Arenas, P. V. Volkov, V. Yu. Volkov, P. Ulloa
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: European Physical Journal C: Particles and Fields, Vol 80, Iss 12, Pp 1-17 (2020)
Druh dokumentu: article
ISSN: 1434-6044
1434-6052
DOI: 10.1140/epjc/s10052-020-08725-x
Popis: Abstract Recently, the ATOMKI experiment has reported new evidence for the excess of $$e^+e^-$$ e + e - events with a mass $$\sim $$ ∼ 17 MeV in the nuclear transitions of $$^4$$ 4 He, that they previously observed in measurements with $$^8$$ 8 Be. These observations could be explained by the existence of a new vector $$X17$$ X 17 boson. So far, the search for the decay $$X17 \rightarrow e^+ e^-$$ X 17 → e + e - with the NA64 experiment at the CERN SPS gave negative results. Here, we present a new technique that could be implemented in NA64 aiming to improve the sensitivity and to cover the remaining $$X17$$ X 17 parameter space. If a signal-like event is detected, an unambiguous observation is achieved by reconstructing the invariant mass of the $$X17$$ X 17 decay with the proposed method. To reach this goal an optimization of the $$X17$$ X 17 production target, as well as an efficient and accurate reconstruction of two close decay tracks, is required. A dedicated analysis of the available experimental data making use of the trackers information is presented. This method provides independent confirmation of the NA64 published results [1], validating the tracking procedure. The detailed Monte Carlo study of the proposed setup and the background estimate show that the goal of the proposed search is feasible.
Databáze: Directory of Open Access Journals
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