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1. Measurement of $CP$ Asymmetries in $B^0\to K_S^0{\pi }^0\gamma$ Decays at Belle II

   https://doi.org/10.1103/PhysRevLett.134.011802  

   Adachi, I; Aggarwal, L; Ahmed, H; Aihara, H; Akopov, N; Aloisio, A; Anh_Ky, N; Asner, D M; Atmacan, H; Aushev, T; et al (January 2025, Physical Review Letters)

   We report measurements of time-dependent $CP$asymmetries in $B^0\to K_S^0{\pi }^0\gamma$decays based on a data sample of $(388\pm 6)\times {10}^{6}B\overline{B}$events collected at the $\mathrm{\Upsilon }\left(4S\right)$resonance with the Belle II detector. The Belle II experiment operates at the SuperKEKB asymmetric-energy $e^{+}{e}^{-}$collider. We measure decay-time distributions to determine $CP$-violating parameters $S$and $C$. We determine these parameters for two ranges of $K_S^0{\pi }^0$invariant mass: $m\left(K_S^0{\pi }^0\right)\in (0.8,1.0)\mathrm{GeV}/c^2$, which is dominated by $B^0\to K^{*0}(\to K_S^0{\pi }^0)\gamma$decays, and a complementary region $m\left(K_S^0{\pi }^0\right)\in (0.6,0.8)\cup (1.0,1.8)\mathrm{GeV}/c^2$. Our results have improved precision as compared to previous measurements and are consistent with theory predictions. Published by the American Physical Society2025 

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2. Study of light-meson resonances decaying to $K_{\mathrm{S}}^{0}K\pi$ in the $B\to \left(K_{\mathrm{S}}^{0}K\pi \right)K$ channels

   https://doi.org/10.1103/PhysRevD.111.092009  

   Aaij, R; Abdelmotteleb, A_S W; Abellan_Beteta, C; Abudinén, F; Ackernley, T; Adefisoye, A A; Adeva, B; Adinolfi, M; Adlarson, P; Agapopoulou, C; et al (May 2025, Physical Review D)

   A study is presented of $B^{+}\to K_{\mathrm{S}}^0{K}^{-}{\pi }^{+}{K}^{+}$and $B^{+}\to K_{\mathrm{S}}^0{K}^{+}{\pi }^{-}{K}^{+}$decays based on the analysis of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. The $K_{\mathrm{S}}^{0}K\pi$invariant-mass distributions of both $B^{+}$decay modes show, in the $m\left(K_{\mathrm{S}}^{0}K\pi \right)<1.85\mathrm{GeV}$mass region, large activity which is resolved using an amplitude analysis. A simple model, where $J^{PC}$amplitudes are described by multiple Breit-Wigner functions with appropriate angular distributions, provides a good description of the experimental data. In this approach a complex mixture of $J^{PC}=0^{-+}$, $1^{++}$and $1^{+-}$amplitudes is observed that is dominated by $\eta \left(1405\right)$, $\eta \left(1470\right)$, $\eta \left(1760\right)$, $f_1\left(1285\right)$, $f_1\left(1420\right)$and $h_1\left(1405\right)$resonances. The $K_{\mathrm{S}}^{0}K\pi$Dalitz plots are dominated by asymmetric crossing $K^{*}\overline{K}$bands which are different for the two $B^{+}$decay modes. This is due to a different interference pattern between the $1^{++}$and $1^{+-}$amplitudes in the two channels. Branching fractions are measured for each resonant contribution. © 2025 CERN, for the LHCb Collaboration2025CERN 

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3. Measurement of the time-integrated $CP$ asymmetry in $D^0\to K_S^0{K}_S^0$ decays using Belle and Belle II data

   https://doi.org/10.1103/PhysRevD.111.012015  

   Adachi, I; Aggarwal, L; Ahmed, H; Aihara, H; Akopov, N; Aloisio, A; Althubiti, N; Anh_Ky, N; Asner, D M; Atmacan, H; et al (January 2025, Physical Review D)

   We measure the time-integrated $CP$asymmetry in $D^0\to K_S^0{K}_S^0$decays reconstructed in $e^{+}{e}^{-}\to c\overline{c}$events collected by the Belle and Belle II experiments. The corresponding data samples have integrated luminosities of 980 and $428{\mathrm{fb}}^{-1}$, respectively. The $D^0$decays are required to originate from the $D^{*+}\to D^0{\pi }^{+}$decay, which determines the charm flavor at production time. A control sample of $D^0\to K^{+}{K}^{-}$decays is used to correct for production and detection asymmetries. The result, $(-1.4\pm 1.3\left(\mathrm{stat}\right)\pm 0.1\left(\mathrm{syst}\right))\%$, is consistent with previous determinations and with $CP$symmetry. Published by the American Physical Society2025 

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4. Observation of the Open-Charm Tetraquark Candidate $T_{cs0}^{*}(2870{)}^0$ in the $B^{-}\to D^{-}{D}^0{K}_S^0$ Decay

   https://doi.org/10.1103/PhysRevLett.134.101901  

   Aaij, R; Abdelmotteleb, A_S W; Abellan_Beteta, C; Abudinén, F; Ackernley, T; Adefisoye, A A; Adeva, B; Adinolfi, M; Adlarson, P; Agapopoulou, C; et al (March 2025, Physical Review Letters)

   An amplitude analysis of $B^{-}\to D^{-}{D}^0{K}_S^0$decays is performed using proton-proton collision data, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A resonant structure of spin-parity $0^{+}$is observed in the $D^0{K}_S^0$invariant-mass spectrum with a significance of $5.3\sigma$. The mass and width of the state, modeled with a Breit-Wigner line shape, are determined to be $2883\pm 11\pm 8\mathrm{MeV}/c^2$and ${87}_{-47}^{+22}\pm 17\mathrm{MeV}$, respectively, where the first uncertainties are statistical and the second systematic. These properties and the quark content are consistent with those of the open-charm tetraquark candidate $T_{cs0}^{*}(2870{)}^0$observed previously in the $D^{+}{K}^{-}$final state of the $B^{-}\to D^{-}{D}^{+}{K}^{-}$decay. This result confirms the existence of the $T_{cs0}^{*}(2870{)}^0$state in a new decay mode. The $T_{cs1}^{*}(2900{)}^0$state, reported in the $B^{-}\to D^{-}{D}^{+}{K}^{-}$decay, is also searched for in the $D^0{K}_S^0$invariant-mass spectrum of the $B^{-}\to D^{-}{D}^0{K}_S^0$decay, without finding evidence for it. © 2025 CERN, for the LHCb Collaboration2025CERN 

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5. Study of ${\mathrm{\Lambda }}_b^0$ and ${\mathrm{\Xi }}_b^0$ Decays to $\mathrm{\Lambda }{h}^{+}{h}^{\prime -}$ and Evidence for $CP$ Violation in ${\mathrm{\Lambda }}_b^0\to \mathrm{\Lambda }{K}^{+}{K}^{-}$ Decays

   https://doi.org/10.1103/PhysRevLett.134.101802  

   Aaij, R; Abdelmotteleb, A_S W; Abellan_Beteta, C; Abudinén, F; Ackernley, T; Adefisoye, A A; Adeva, B; Adinolfi, M; Adlarson, P; Agapopoulou, C; et al (March 2025, Physical Review Letters)

   A study of ${\mathrm{\Lambda }}_b^0$and ${\mathrm{\Xi }}_b^0$decays to $\mathrm{\Lambda }{h}^{+}{h}^{\prime -}$( $h^{(\prime )}=\pi ,K$) is performed using $pp$collision data collected by the LHCb experiment during LHC Runs 1–2, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. The branching fractions for these decays are measured using the ${\mathrm{\Lambda }}_b^0\to {\mathrm{\Lambda }}_c^{+}(\to \mathrm{\Lambda }{\pi }^{+}){\pi }^{-}$decay as a control channel. The decays ${\mathrm{\Lambda }}_b^0\to \mathrm{\Lambda }{\pi }^{+}{\pi }^{-}$and ${\mathrm{\Xi }}_b^0\to \mathrm{\Lambda }{K}^{-}{\pi }^{+}$are observed for the first time. For decay modes with sufficient signal yields, $CP$asymmetries are measured in the full and localized regions of the final-state phase space. Evidence is found for $CP$violation in the ${\mathrm{\Lambda }}_b^0\to \mathrm{\Lambda }{K}^{+}{K}^{-}$decay, interpreted as originating primarily from an asymmetric ${\mathrm{\Lambda }}_b^0\to N^{*+}{K}^{-}$decay amplitude. The measured $CP$asymmetries for other decays are compatible with zero. © 2025 CERN, for the LHCb Collaboration2025CERN 

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