TY  - JOUR
AU  - Natochii, Andrii
AU  - Browder, T. E.
AU  - Cao, L.
AU  - Cautero, G.
AU  - Dreyer, S.
AU  - Frey, A.
AU  - Gabrielli, A.
AU  - Giuressi, D.
AU  - Ishibashi, T.
AU  - Jin, Y.
AU  - Kojima, K.
AU  - Kraetzschmar, T.
AU  - Lanceri, L.
AU  - Liptak, Z.
AU  - Liventsev, D.
AU  - Marinas, C.
AU  - Massaccesi, L.
AU  - Matsuoka, K.
AU  - Meier, F.
AU  - Miller, C.
AU  - Nakayama, H.
AU  - Niebuhr, C.
AU  - Novosel, A.
AU  - Parham, K.
AU  - Popov, I.
AU  - Rizzo, G.
AU  - Roney, J. M.
AU  - Ryu, S. Y.
AU  - Santelj, L.
AU  - Schneider, S.
AU  - Schueler, J.
AU  - Schwenker, B.
AU  - Shi, X. D.
AU  - Simon, F.
AU  - Stefkova, S.
AU  - Takahashi, M.
AU  - Tanigawa, H.
AU  - Taniguchi, N.
AU  - Terui, S.
AU  - Vahsen, S. E.
AU  - Vitale, L.
AU  - Vossen, A.
AU  - Wang, Z.
AU  - Wiechczynski, J.
AU  - Windel, H.
AU  - Yoshihara, K.
TI  - Measured and projected beam backgrounds in the Belle II experiment at the SuperKEKB collider
JO  - Nuclear instruments & methods in physics research / Section A
VL  - 1055
IS  - arXiv:2302.01566
SN  - 0167-5087
CY  - Amsterdam
PB  - North-Holland Publ. Co.
M1  - PUBDB-2023-07487
M1  - arXiv:2302.01566
SP  - 168550
PY  - 2023
N1  - 28 pages, 17 figures, 9 tables (revised)
AB  - The Belle II experiment at the SuperKEKB electron–positron collider aims to collect an unprecedented data set of 50 ab<sup>−1</sup> to study CP-violation in the B-meson system and to search for Physics beyond the Standard Model. SuperKEKB is already the world’s highest-luminosity collider. In order to collect the planned data set within approximately one decade, the target is to reach a peak luminosity of 6 x 10<sup>35</sup> cm<sup>−2</sup> s<sup>−1</sup> by further increasing the beam currents and reducing the beam size at the interaction point by squeezing the betatron function down to β<sup>*</sup><sub>y</sub> = 0.3 mm. To ensure detector longevity and maintain good reconstruction performance, beam backgrounds must remain well controlled. We report on current background rates in Belle II and compare these against simulation. We find that a number of recent refinements have significantly improved the background simulation accuracy. Finally, we estimate the safety margins going forward. We predict that backgrounds should remain high but acceptable until a luminosity of at least 2.8 x 10<sup>35</sup> cm<sup>−2</sup> s<sup>−1</sup> is reached for β<sup>*</sup><sub>y</sub> = 0.6 mm. At this point, the most vulnerable Belle II detectors, the Time-of-Propagation (TOP) particle identification system and the Central Drift Chamber (CDC), have predicted background hit rates from single-beam and luminosity backgrounds that add up to approximately half of the maximum acceptable rates.  
KW  - electron positron: annihilation (INSPIRE)
KW  - electron positron: colliding beams (INSPIRE)
KW  - beam: background (INSPIRE)
KW  - vertex: primary (INSPIRE)
KW  - beam: size (INSPIRE)
KW  - BELLE (INSPIRE)
KW  - KEK-B (INSPIRE)
KW  - new physics: search for (INSPIRE)
KW  - CP: violation (INSPIRE)
KW  - particle identification (INSPIRE)
KW  - drift chamber (INSPIRE)
KW  - safety (INSPIRE)
KW  - performance (INSPIRE)
KW  - betatron (INSPIRE)
KW  - experimental results (INSPIRE)
KW  - Detector background (autogen)
KW  - Lepton collider (autogen)
KW  - Monte-Carlo simulation (autogen)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:001056103200001
DO  - DOI:10.1016/j.nima.2023.168550
UR  - https://bib-pubdb1.desy.de/record/599761
ER  -