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1. Observation of $B_c^{+}\to D{h}^{+}{h}^{-}$ Decays

   https://doi.org/10.1103/fsj9-89jt  

   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 (January 2026, Physical Review Letters)

   Searches are presented for $B_c^{+}\to D{h}^{+}{h}^{-}$ decays, where $D$ is a charmed meson and $h^{\pm }$ is a charged pion or kaon, using $pp$ collision data collected by the LHCb experiment corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$ . The decays $B_c^{+}\to D^{+}{K}^{+}{\pi }^{-}$ , $B_c^{+}\to D^{*+}{K}^{+}{\pi }^{-}$ , and $B_c^{+}\to D_s^{+}{K}^{+}{K}^{-}$ are observed for the first time. Their branching fractions, expressed as ratios relative to that of the $B_c^{+}\to B_s^0{\pi }^{+}$ decay, are determined to be $\mathcal{R}(B_c^{+}\to D^{+}{K}^{+}{\pi }^{-})=(1.96\pm 0.23\pm 0.08\pm 0.10)\times {10}^{-3}$ , $\mathcal{R}(B_c^{+}\to D^{*+}{K}^{+}{\pi }^{-})=(3.67\pm 0.55\pm 0.24\pm 0.20)\times {10}^{-3}$ , $\mathcal{R}(B_c^{+}\to D_s^{+}{K}^{+}{K}^{-})=(1.61\pm 0.35\pm 0.13\pm 0.07)\times {10}^{-3}$ , where the first uncertainty is statistical, the second is systematic, and the third is due to the limited precision on the $D$ -meson branching fractions. The decay channels proceed primarily through excited $K^0$ or $D^0$ resonances or $\varphi$ mesons, and open a new avenue for studies of charge-parity violation in beauty mesons. 

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2. Search for Baryon-Number-Violating Processes in $B^{-}$ Decays to the ${\overline{\mathrm{\Xi }}}_c^0{\overline{\mathrm{\Lambda }}}_c^{-}$ Final State

   https://doi.org/10.1103/PhysRevLett.133.071802  

   Gu, T; Savinov, V; Adachi, I; Aihara, H; Asner, D M; Atmacan, H; Aushev, T; Ayad, R; Banerjee, Sw; Belous, K; et al (August 2024, Physical Review Letters)

   We report the results of the first search for $B^{-}$ decays to the ${\overline{\mathrm{\Xi }}}_c^0{\overline{\mathrm{\Lambda }}}_c^{-}$ final state using $711{\mathrm{fb}}^{-1}$ of data collected at the $\mathrm{\Upsilon }\left(4S\right)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The results are interpreted in terms of both direct baryon-number-violating $B^{-}$ decay and ${\mathrm{\Xi }}_c^0-{\overline{\mathrm{\Xi }}}_c^0$ oscillations which follow the standard model decay $B^{-}\to {\mathrm{\Xi }}_c^0{\overline{\mathrm{\Lambda }}}_c^{-}$ . We observe no evidence for baryon number violation and set the 95% confidence-level upper limits on the ratio of baryon-number-violating and standard model branching fractions $\mathcal{B}(B^{-}\to {\overline{\mathrm{\Xi }}}_c^0{\overline{\mathrm{\Lambda }}}_c^{-})/\mathcal{B}(B^{-}\to {\mathrm{\Xi }}_c^0{\overline{\mathrm{\Lambda }}}_c^{-})$ to be $<2.7\%$ and on the effective angular frequency of mixing $\omega$ in ${\mathrm{\Xi }}_c^0-{\overline{\mathrm{\Xi }}}_c^0$ oscillations to be $<0.76{\mathrm{ps}}^{-1}$ (equivalent to ${\tau }_{\mathrm{mix}}>1.3\mathrm{ps}$ ). Published by the American Physical Society2024 

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3. Evidence for $B^{-}\to D^{**0}{\tau }^{-}\overline{{\nu }_{\tau }}$ Decays

   https://doi.org/10.1103/rj9h-n4w1  

   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 (July 2025, Physical Review Letters)

   The first evidence for the decay $B^{-}\to D^{**0}{\tau }^{-}{\overline{\nu }}_{\tau }$ is obtained using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$ , at centre-of-mass energies of 7, 8, and 13 TeV. Here, the $D^{**0}$ meson represents any of the three excited charm mesons $D_1(2420{)}^0$ , $D_2^{*}(2460{)}^0$ , and $D_1^{\prime }(2400{)}^0$ . The $B^{-}\to D^{**0}{\tau }^{-}{\overline{\nu }}_{\tau }$ signal is measured with a significance of $3.5\sigma$ , including systematic uncertainties. The combined branching fraction $\mathcal{B}(B^{-}\to D_{1,2}^{**0}{\tau }^{-}{\overline{\nu }}_{\tau })\times \mathcal{B}(D_{1,2}^{**0}\to D^{*+}{\pi }^{-})$ , where $D_{1,2}^{**0}$ denotes both $D_1(2420{)}^0$ and $D_2^{*}(2460{)}^0$ contributions, is measured to be $[0.051\pm 0.013\left(\mathrm{stat}\right)\pm 0.006\left(\mathrm{syst}\right)\pm 0.009(\mathrm{ext}\left)\right]\%$ , where the last uncertainty reflects that of the branching fraction of the normalization channel $B^{-}\to D_{1,2}^{**0}{D_s^{-}}^{(*)}$ . The ratio between the tauonic and muonic semileptonic $B$ decays, with the latter taken from world average values, is also determined and found to be $\mathcal{R}\left(D_{1,2}^{**0}\right)=0.13\pm 0.03\left(\mathrm{stat}\right)\pm 0.01\left(\mathrm{syst}\right)\pm 0.02\left(\mathrm{ext}\right)$ . 

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4. Observation of the Radiative Decay $D_{s0}^{*}(2317{)}^{+}\to D_s^{*+}\gamma$

   https://doi.org/10.1103/vcld-225s  

   Abumusabh, M; Adachi, I; Aggarwal, L; Ahmed, H; Ahn, Y; Aihara, H; Akopov, N; Alghamdi, S; Alhakami, M; Aloisio, A; et al (June 2026, Physical Review Letters)

   We report the first observation of the radiative decay $D_{s0}^{*}(2317{)}^{+}\to D_s^{*+}\gamma$ with a statistical significance exceeding 10 standard deviations. The signal is observed in the continuum $e^{+}{e}^{-}\to c\overline{c}$ process, using combined data samples of $980.4{\mathrm{fb}}^{-1}$ from Belle and $427.9{\mathrm{fb}}^{-1}$ from Belle II, collected at the KEKB and SuperKEKB asymmetric-energy $e^{+}{e}^{-}$ colliders, respectively. The branching fraction ratio $\mathcal{B}\left[D_{s0}^{*}\right(2317{)}^{+}\to D_s^{*+}\gamma ]/\mathcal{B}[D_{s0}^{*}(2317{)}^{+}\to D_s^{+}{\pi }^0]$ is measured to be $[7.13\pm 0.70(\mathrm{stat})\pm 0.26(\mathrm{syst}\left)\right]\%$ . This result provides crucial discrimination between theoretical models of the $D_{s0}^{*}(2317{)}^{+}$ structure. 

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5. 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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