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1. 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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2. Branching fraction measurement of the decay $B^{+}\to \psi \left(2S\right)\varphi \left(1020\right)K^{+}$

   https://doi.org/10.1103/PhysRevD.111.092008  

   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)

   The branching fraction of the decay $B^{+}\to \psi \left(2S\right)\varphi \left(1020\right)K^{+}$, relative to the topologically similar decay $B^{+}\to J/\psi \varphi \left(1020\right)K^{+}$, is measured using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. The ratio is found to be $0.061\pm 0.004\pm 0.009$, where the first uncertainty is statistical and the second systematic. Using the world-average branching fraction for $B^{+}\to J/\psi \varphi \left(1020\right)K^{+}$, the branching fraction for the decay $B^{+}\to \psi \left(2S\right)\varphi \left(1020\right)K^{+}$is found to be $(3.0\pm 0.2\pm 0.5\pm 0.2)\times {10}^{-6}$, where the first uncertainty is statistical, the second systematic, and the third is due to the branching fraction of the normalization channel. © 2025 CERN, for the LHCb Collaboration2025CERN 

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3. Observation of the $J/\psi \to {\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$ decay in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$

   https://doi.org/10.1103/PhysRevD.109.L111101  

   Hayrapetyan, A; Tumasyan, A; Adam, W; Andrejkovic, J W; Bergauer, T; Chatterjee, S; Damanakis, K; Dragicevic, M; Hussain, P S; Jeitler, M; et al (June 2024, Physical Review D)

   The $J/\psi \to {\mu }^{+}{\mu }^{-}{\mu }^{+}{\mu }^{-}$decay has been observed with a statistical significance in excess of five standard deviations. The analysis is based on an event sample of proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment in 2018 and corresponding to an integrated luminosity of $33.6{\mathrm{fb}}^{-1}$. Normalizing to the $J/\psi \to {\mu }^{+}{\mu }^{-}$decay mode leads to a branching fraction of $[{10.1}_{-2.7}^{+3.3}\left(\mathrm{stat}\right)\pm 0.4\left(\mathrm{syst}\right)]\times {10}^{-7}$, a value that is consistent with the standard model prediction. © 2024 CERN, for the CMS Collaboration2024CERN 

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4. Measurement of the branching fraction of the decay $B^{-}\to D^0\rho (770{)}^{-}$ at Belle II

   https://doi.org/10.1103/PhysRevD.109.L111103  

   Adachi, I; Aggarwal, L; Aihara, H; Akopov, N; Aloisio, A; Anh_Ky, N; Asner, D M; Atmacan, H; Aushev, V; Aversano, M; et al (June 2024, Physical Review D)

   We measure the branching fraction of the decay $B^{-}\to D^0\rho (770{)}^{-}$using data collected with the Belle II detector. The data contain 387 million $B\overline{B}$pairs produced in $e^{+}{e}^{-}$collisions at the $\mathrm{\Upsilon }\left(4S\right)$resonance. We reconstruct $8360\pm 180$decays from an analysis of the distributions of the $B^{-}$energy and the $\rho (770{)}^{-}$helicity angle. We determine the branching fraction to be $(0.939\pm 0.021\left(\mathrm{stat}\right)\pm 0.050\left(\mathrm{syst}\right))\%$, in agreement with previous results. Our measurement improves the relative precision of the world average by more than a factor of two. Published by the American Physical Society2024 

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5. Measurement of the branching fraction and $CP$ -violating asymmetry of the decay $B^0\to {\pi }^0{\pi }^0$ using 387 million $\mathrm{\Upsilon }\left(4S\right)$ decays in Belle II data

   https://doi.org/10.1103/PhysRevD.111.L071102  

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

   We measure the branching fraction and $CP$-violating flavor-dependent rate asymmetry of $B^0\to {\pi }^0{\pi }^0$decays reconstructed using the Belle II detector in an electron-positron collision sample containing $387\times {10}^6\mathrm{\Upsilon }\left(4S\right)$mesons. Using an optimized event selection, we find $125\pm 20$signal decays in a fit to background-discriminating and flavor-sensitive distributions. The resulting branching fraction is $(1.25\pm 0.23)\times {10}^{-6}$and the $CP$-violating asymmetry is $0.03\pm 0.30$. Published by the American Physical Society2025 

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