We report on a search for a resonance X decaying to a pair of muons in e(+) e(-) mu(+)mu(-) X events in the 0.212-9.000 GeV/c(2) mass range, using 178 fb(-1) of data collected by the Belle II experiment at the SuperKEKB collider at a center of mass energy of 10.58 GeV. The analysis probes two different models of X beyond the standard model: a Z' vector boson in the L-mu - L-tau model and a muonphilic scalar. We observe no evidence for a signal and set exclusion limits at the 90% confidence level on the products of cross section and branching fraction for these processes, ranging from 0.046 fb to 0.97 fb for the L-mu - L-tau model and from 0.055 fb to 1.3 fb for the muonphilic scalar model. For masses below 6 GeV/c(2), the corresponding constraints on the couplings of these processes to the standard model range from 0.0008 to 0.039 for the L-mu - L-tau model and from 0.0018 to 0.040 for the muonphilic scalar model. These are the first constraints on the muonphilic scalar from a dedicated search.

Search for a μ+μ- resonance in four-muon final states at Belle II

Bettarini, S.;Casarosa, G.;Forti, F.;Massaccesi, L.;Rizzo, G.;Tenchini, F.;
2024-01-01

Abstract

We report on a search for a resonance X decaying to a pair of muons in e(+) e(-) mu(+)mu(-) X events in the 0.212-9.000 GeV/c(2) mass range, using 178 fb(-1) of data collected by the Belle II experiment at the SuperKEKB collider at a center of mass energy of 10.58 GeV. The analysis probes two different models of X beyond the standard model: a Z' vector boson in the L-mu - L-tau model and a muonphilic scalar. We observe no evidence for a signal and set exclusion limits at the 90% confidence level on the products of cross section and branching fraction for these processes, ranging from 0.046 fb to 0.97 fb for the L-mu - L-tau model and from 0.055 fb to 1.3 fb for the muonphilic scalar model. For masses below 6 GeV/c(2), the corresponding constraints on the couplings of these processes to the standard model range from 0.0008 to 0.039 for the L-mu - L-tau model and from 0.0018 to 0.040 for the muonphilic scalar model. These are the first constraints on the muonphilic scalar from a dedicated search.
2024
Adachi, I.; Adamczyk, K.; Aggarwal, L.; Ahmed, H.; Aihara, H.; Akopov, N.; Aloisio, A.; Anh Ky, N.; Asner, D.  M.; Atmacan, H.; Aushev, V.; Aversano, ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/1274619
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