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First Observation of a Doubly Charged Tetraquark and Its Neutral Partner

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A combined amplitude analysis is performed for the decays B0 → D0 Dþ s π− and Bþ → D−Dþ s πþ, which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in protonproton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb−1. Two new resonant states with masses of 2.908  0.011  0.020 GeV and widths of 0.136  0.023  0.013 GeV are observed, which decay to Dþ s πþ and Dþ s π− respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content ½csu¯ d¯, and the latter state is a neutral tetraquark composed of ½cs¯ u d¯  quarks. Both states are found to have spin-parity of 0þ, and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.

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Physical Review Letters, 2023, vol. 131, num.4

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Articles publicats en revistes (Física Quàntica i Astrofísica)

# metadata.dc.title[].value
First Observation of a Doubly Charged Tetraquark and Its Neutral Partner