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1. Two-Pole Nature of the Lambda(1405) Resonance from Lattice QCD

   https://doi.org/10.1103/PhysRevLett.132.051901  

   Bulava, John; Cid-Mora, Bárbara; Hanlon, Andrew D.; Hörz, Ben; Mohler, Daniel; Morningstar, Colin; Moscoso, Joseph; Nicholson, Amy; Romero-López, Fernando; Skinner, Sarah; et al (January 2024, Physical Review Letters)

   This Letter presents the first lattice QCD computation of the coupled channel πΣ−¯KN scattering amplitudes at energies near 1405 MeV. These amplitudes contain the resonance Λ(1405) with strangeness S=−1 and isospin, spin, and parity quantum numbers I(JP)=0(1/2−). However, whether there is a single resonance or two nearby resonance poles in this region is controversial theoretically and experimentally. Using single-baryon and meson-baryon operators to extract the finite-volume stationary-state energies to obtain the scattering amplitudes at slightly unphysical quark masses corresponding to mπ≈200  MeV and mK≈487  MeV, this study finds the amplitudes exhibit a virtual bound state below the πΣ threshold in addition to the established resonance pole just below the ¯KN threshold. Several parametrizations of the two-channel K matrix are employed to fit the lattice QCD results, all of which support the two-pole picture suggested by SU(3) chiral symmetry and unitarity. 

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2. Search for light tetraquark states in $\mathrm{\Upsilon }\left(1S\right)$ and $\mathrm{\Upsilon }\left(2S\right)$ decays

   https://doi.org/10.1103/PhysRevD.96.112002  

   Jia, S.; Shen, C. P.; Yuan, C. Z.; Adachi, I.; Ahn, J. K.; Aihara, H.; Al Said, S.; Asner, D. M.; Atmacan, H.; Aushev, T.; et al (December 2017, Physical Review D)

   null (Ed.)
3. The Λ(1405) pole structure from Lattice QCD: A coupled-channel πΣ−KN study

   https://doi.org/10.1051/epjconf/202430301004  

   Bulava, John; Cid-Mora, Bárbara; Hanlon, Andrew D; Hörz, Ben; Mohler, Daniel; Morningstar, Colin; Moscoso, Joseph; Nicholson, Amy; Romero-López, Fernando; Skinner, Sarah; et al (January 2024, EPJ Web of Conferences)

   Hüsken, N; Danilkin, I; Hagelstein, F (Ed.)

   This report summarizes results of the first lattice QCD calculation of coupled-channelπΣ−K¯Nscattering in the Λ(1405) region. This study was carried out using a single CLS ensemble with a heavier-than-physical pion mass m_π≈ 200 MeV and a lighter-than-physical kaon mass m_K>≈ 487 MeV. Once the finite-volume energy spectrum has been reliably extracted, the Lüscher method was employed to obtain scattering amplitudes. Through a variety of parametrizations of the two-channel K-matrix, the final results show a virtual bound state below the πΣ threshold and a resonance right below K¯N. 

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4. Search for $\mathrm{\Omega }\left(2012\right)\to K\mathrm{\Xi }\left(1530\right)\to K\pi \mathrm{\Xi }$ at Belle

   https://doi.org/10.1103/PhysRevD.100.032006  

   Jia, S.; Shen, C. P.; Adachi, I.; Ahn, J. K.; Aihara, H.; Al Said, S.; Asner, D. M.; Aushev, T.; Ayad, R.; Babu, V.; et al (August 2019, Physical Review D)
5. Search for transitions from $\mathrm{\Upsilon }\left(4S\right)$ and $\mathrm{\Upsilon }\left(5S\right)$ to ${\eta }_b\left(1S\right)$ and ${\eta }_b\left(2S\right)$ with emission of an $\omega$ meson

   https://doi.org/10.1103/PhysRevD.102.092011  

   Oskin, P.; Mizuk, R.; Aihara, H.; Asner, D. M.; Atmacan, H.; Aulchenko, V.; Aushev, T.; Ayad, R.; Behera, P.; Belous, K.; et al (November 2020, Physical Review D)

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