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1. Search for $D^0$ meson decays to ${\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ and $K^{+}{K}^{-}{e}^{+}{e}^{-}$ final states

   https://doi.org/10.1103/PhysRevD.111.L091101  

   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 search for $D^0$ meson decays to the ${\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ and $K^{+}{K}^{-}{e}^{+}{e}^{-}$ final states is reported using a sample of proton-proton collisions collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of $6{\mathrm{fb}}^{-1}$ . The decay $D^0\to {\pi }^{+}{\pi }^{-}{e}^{+}{e}^{-}$ is observed for the first time when requiring that the two electrons are consistent with coming from the decay of a $\varphi$ or ${\rho }^0/\omega$ meson. The corresponding branching fractions are measured relative to the $D^0\to K^{-}{\pi }^{-}[e^{+}{e}^{-}{]}_{{\rho }^0/\omega }$ decay, where the two electrons are consistent with coming from the decay of a ${\rho }^0$ or $\omega$ meson. No evidence is found for the $D^0\to K^{+}{K}^{-}{e}^{+}{e}^{-}$ decay and world-best limits are set on its branching fraction. The results are compared to, and found to be consistent with, the branching fractions of the $D^0\to {\pi }^{+}{\pi }^{-}{\mu }^{+}{\mu }^{-}$ and $D^0\to K^{+}{K}^{-}{\mu }^{+}{\mu }^{-}$ decays recently measured by LHCb and confirm lepton universality at the current precision. © 2025 CERN, for the LHCb Collaboration2025CERN 

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2. Measurement of $CP$ Violation Observables in $D^{+}\to K^{-}{K}^{+}{\pi }^{+}$ Decays

   https://doi.org/10.1103/PhysRevLett.133.251801  

   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 (December 2024, Physical Review Letters)

   A search for violation of the charge-parity ( $CP$ ) symmetry in the $D^{+}\to K^{-}{K}^{+}{\pi }^{+}$ decay is presented, with proton-proton collision data corresponding to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$ , collected at a center-of-mass energy of 13 TeV with the LHCb detector. A novel model-independent technique is used to compare the $D^{+}$ and $D^{-}$ phase-space distributions, with instrumental asymmetries subtracted using the $D_s^{+}\to K^{-}{K}^{+}{\pi }^{+}$ decay as a control channel. The $p$ value for the hypothesis of $CP$ conservation is 8.1%. The $CP$ asymmetry observables $A_{CP|S}^{\varphi {\pi }^{+}}=(0.95\pm 0.43_{\mathrm{stat}}\pm 0.26_{\mathrm{syst}})\times {10}^{-3}$ and $A_{CP|S}^{{\overline{K}}^{*0}{K}^{+}}=(-0.26\pm 0.56_{\mathrm{stat}}\pm 0.18_{\mathrm{syst}})\times {10}^{-3}$ are also measured. These results show no evidence of $CP$ violation and represent the most sensitive search performed through the phase space of a multibody decay. © 2024 CERN, for the LHCb Collaboration2024CERN 

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3. Searches for $B^0\to K^{+}{\pi }^{-}{\tau }^{+}{\tau }^{-}$ and $B_s^0\to K^{+}{K}^{-}{\tau }^{+}{\tau }^{-}$ Decays

   https://doi.org/10.1103/y968-44v8  

   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 2026, Physical Review Letters)

   The first searches for $B^0\to K^{+}{\pi }^{-}{\tau }^{+}{\tau }^{-}$ and $B_s^0\to K^{+}{K}^{-}{\tau }^{+}{\tau }^{-}$ decays at the LHCb experiment are conducted with $pp$ collision data corresponding to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$ . The tau leptons are reconstructed using the ${\tau }^{+}\to {\mu }^{+}{\overline{\nu }}_{\tau }{\nu }_{\mu }$ decay and the results are presented in bins of $K^{+}{\pi }^{-}$ or $K^{+}{K}^{-}$ mass. No signal is observed and upper limits are set on the branching fractions. The searches result in the first upper limits for $B^0\to K^{+}{\pi }^{-}{\tau }^{+}{\tau }^{-}$ decays outside the $K^{*}(892{)}^0$ region in $K^{+}{\pi }^{-}$ mass and the first limits for $B_s^0\to K^{+}{K}^{-}{\tau }^{+}{\tau }^{-}$ decays. The searches are recast into limits on the decays $B^0\to K^{*}(892{)}^0{\tau }^{+}{\tau }^{-}$ and $B_s^0\to \varphi \left(1020\right){\tau }^{+}{\tau }^{-}$ , yielding $2.8\times {10}^{-4}$ ( $2.5\times {10}^{-4}$ ) and $4.7\times {10}^{-4}$ ( $4.1\times {10}^{-4}$ ) at the 95% (90%) confidence level, respectively. For the decay $B^0\to K^{*}(892{)}^0{\tau }^{+}{\tau }^{-}$ , this result improves on the current best upper limit by an order of magnitude. 

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4. Angular analysis of the low $K^{+}{K}^{-}$ invariant mass enhancement in $B^{+}\to K^{+}{K}^{-}{\pi }^{+}$ decays

   https://doi.org/10.1103/PhysRevD.107.032013  

   Hsu, C.-L.; Sevior, M. E.; Adachi, I.; Aihara, H.; Al Said, S.; Asner, D. M.; Atmacan, H.; Aulchenko, V.; Aushev, T.; Ayad, R.; et al (February 2023, Physical Review D)
5. Search for a ${\tau }^{+}{\tau }^{-}$ Resonance in $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}{\tau }^{+}{\tau }^{-}$ Events with the Belle II Experiment

   https://doi.org/10.1103/PhysRevLett.131.121802  

   Adachi, I; Adamczyk, K; Aggarwal, L; Ahmed, H; Aihara, H; Akopov, N; Aloisio, A; Anh_Ky, N; Asner, D M; Atmacan, H; et al (September 2023, Physical Review Letters)