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1. Measurement of the branching fractions of $$ \overline{B} $$ → D(*)K−$$ {K}_{(S)}^{\left(\ast \right)0} $$ and $$ \overline{B} $$ → D(*)$$ {D}_s^{-} $$ decays at Belle II

   https://doi.org/10.1007/JHEP08(2024)206  

   Adachi, I; Aggarwal, L; Aihara, H; Akopov, N; Aloisio, A; Althubiti, N; Anh_Ky, N; Asner, D M; Atmacan, H; Aushev, T; et al (August 2024, Journal of High Energy Physics)

   Abstract We present measurements of the branching fractions of eight$$ {\overline{B}}^0 $$ ${\overline{B}}^0$ →D^(*)+K⁻$$ {K}_{(S)}^{\left(\ast \right)0} $$ $K_{\left(S\right)}^{\left(\ast \right)0}$ ,B⁻→D^(*)0K⁻$$ {K}_{(S)}^{\left(\ast \right)0} $$ $K_{\left(S\right)}^{\left(\ast \right)0}$ decay channels. The results are based on data from SuperKEKB electron-positron collisions at the Υ(4S) resonance collected with the Belle II detector, corresponding to an integrated luminosity of 362 fb⁻¹. The event yields are extracted from fits to the distributions of the difference between expected and observedBmeson energy, and are efficiency-corrected as a function ofm(K⁻$$ {K}_{(S)}^{\left(\ast \right)0} $$ $K_{\left(S\right)}^{\left(\ast \right)0}$ ) andm(D^(*)$$ {K}_{(S)}^{\left(\ast \right)0} $$ $K_{\left(S\right)}^{\left(\ast \right)0}$ ) in order to avoid dependence on the decay model. These results include the first observation of$$ {\overline{B}}^0 $$ ${\overline{B}}^0$ →D⁺K⁻$$ {K}_S^0 $$ $K_S^0$ ,B⁻→D*⁰K⁻$$ {K}_S^0 $$ $K_S^0$ , and$$ {\overline{B}}^0 $$ ${\overline{B}}^0$ →D*⁺K⁻$$ {K}_S^0 $$ $K_S^0$ decays and a significant improvement in the precision of the other channels compared to previous measurements. The helicity-angle distributions and the invariant mass distributions of theK⁻$$ {K}_{(S)}^{\left(\ast \right)0} $$ $K_{\left(S\right)}^{\left(\ast \right)0}$ systems are compatible with quasi-two-body decays via a resonant transition with spin-parityJ^P= 1⁻for theK⁻$$ {K}_S^0 $$ $K_S^0$ systems andJ^P= 1⁺for theK⁻K*⁰systems. We also present measurements of the branching fractions of four$$ {\overline{B}}^0 $$ ${\overline{B}}^0$ →D^(*)+$$ {D}_s^{-} $$ $D_s^{-}$ ,B⁻→D^(*)0$$ {D}_s^{-} $$ $D_s^{-}$ decay channels with a precision compatible to the current world averages. 

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2. Observation of the decay $$ {B}_s^0\to {K}^0p\overline{p} $$ and measurement of the $$ {B}_{(s)}^0\to {K}^0p\overline{p} $$ branching fractions

   https://doi.org/10.1007/JHEP07(2025)121  

   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, Journal of High Energy Physics)

   A<sc>bstract</sc> A study of the charmless baryonic decays$$ {B}_{(s)}^0\to {K}^0p\overline{p} $$ $B_{\left(s\right)}^0\to K^{0}p\overline{p}$ is presented, where$$ {B}_{(s)}^0 $$ $B_{\left(s\right)}^0$ denotes either aB⁰or a$$ {B}_s^0 $$ $B_s^0$ meson. The analysis is based on proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb⁻¹. The decay$$ {B}_s^0\to {K}^0p\overline{p} $$ $B_s^0\to K^{0}p\overline{p}$ is observed for the first time, with a measured branching fraction of (9.14±1.69±0.90±0.33±0.20)×10⁻⁷and a significance of 5.6σ. The uncertainties respectively account for statistical and systematic contributions, the precision of the branching fraction of the normalisation channelB⁰→ K⁰π⁺π⁻and the fragmentation fraction ratiof_s/f_d. The branching fraction determined for$$ {B}^0\to {K}^0p\overline{p} $$ $B^0\to K^{0}p\overline{p}$ is (2.82±0.08±0.12±0.10)×10⁻⁶, which is the most precise measurement to date. 

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3. Measurement of CP asymmetry in $$ {\textrm{B}}_{\textrm{s}}^0\to {\textrm{D}}_{\textrm{s}}^{\mp }{\textrm{K}}^{\pm } $$ decays

   https://doi.org/10.1007/JHEP03(2025)139  

   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, Journal of High Energy Physics)

   A<sc>bstract</sc> A measurement of theCP-violating parameters in$$ {B}_s^0\boldsymbol{\to}{D}_s^{\mp }{K}^{\pm} $$ $B_s^0\to D_s^{\mp }{K}^{\pm }$ decays is reported, based on the analysis of proton-proton collision data collected by the LHCb experiment corresponding to an integrated luminosity of 6 fb⁻¹at a centre-of-mass energy of 13 TeV. The measured parameters are obtained with a decay-time dependent analysis yieldingC_f= 0.791 ± 0.061 ± 0.022,$$ {A}_f^{\Delta \Gamma} $$ $A_f^{\text{∆}\Gamma }$ = −0.051 ± 0.134 ± 0.058,$$ {A}_{\overline{f}}^{\Delta \Gamma} $$ $A_{\overline{f}}^{\text{∆}\Gamma }$ = −0.303 ± 0.125 ± 0.055,S_f= −0.571 ± 0.084 ± 0.023 and$$ {S}_{\overline{f}} $$ $S_{\overline{f}}$ = −0.503 ± 0.084 ± 0.025, where the first uncertainty is statistical and the second systematic. This corresponds to CP violation in the interference between mixing and decay of about 8.6σ. Together with the value of the$$ {B}_s^0 $$ $B_s^0$ mixing phase −2β_s, these parameters are used to obtain a measurement of the CKM angleγequal to (74 ± 12)° modulo 180°, where the uncertainty contains both statistical and systematic contributions. This result is combined with the previous LHCb measurement in this channel using 3 fb⁻¹resulting in a determination of$$ \gamma ={\left({81}_{-11}^{+12}\right)}^{\circ } $$ $\gamma ={\left({81}_{-11}^{+12}\right)}^{\circ }$ . 

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4. CP violation in K → μ+μ− with and without time dependence through a tagged analysis

   https://doi.org/10.1007/JHEP09(2025)190  

   D’Ambrosio, Giancarlo; Dery, Avital; Grossman, Yuval; Kitahara, Teppei; Marchevski, Radoslav; Santos, Diego Martínez; Schacht, Stefan (September 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> We point out that using current knowledge of$$ \mathcal{B}\left({K}_L^0\to {\mu}^{+}{\mu}^{-}\right) $$ $B\left(K_L^0\to {\mu }^{+}{\mu }^{-}\right)$ and$$ \mathcal{B}\left({K}_L^0\to \gamma \gamma \right) $$ $B\left(K_L^0\to \mathrm{\gamma \gamma }\right)$ , one can extract short-distance information from the combined measurement of the time-integrated CP asymmetry,A_CP(K⁰→ μ⁺μ⁻), and of$$ \mathcal{B}\left({K}_S^0\to {\mu}^{+}{\mu}^{-}\right) $$ $B\left(K_S^0\to {\mu }^{+}{\mu }^{-}\right)$ . We discuss the interplay between this set of observables, and demonstrate that determining sign[A_CP(K⁰→μ⁺μ⁻)] would eliminate the discrete ambiguity in the Standard Model prediction for$$ \mathcal{B}\left({K}_L^0\to {\mu}^{+}{\mu}^{-}\right) $$ $B\left(K_L^0\to {\mu }^{+}{\mu }^{-}\right)$ . We then move on to feasibility studies within an LHCb-like setup, using both time-integrated and time-dependent information, employingK⁰and$$ {\overline{K}}^0 $$ ${\overline{K}}^0$ tagging methods. We find that, within an optimistic scenario, the short-distance amplitude, proportional to the CKM parameter combination$$ \mid {A}^2{\lambda}^5\overline{\eta}\mid $$ $\mid A^2{\lambda }^5\overline{\eta }\mid$ , could be constrained by LHCb at the level of about 35% of its Standard Model value, and the discrete ambiguity in$$ \mathcal{B}{\left({K}_L^0\to {\mu}^{+}{\mu}^{-}\right)}_{\textrm{SM}} $$ $B{\left(K_L^0\to {\mu }^{+}{\mu }^{-}\right)}_{\mathrm{SM}}$ could be resolved at more than 3σby the end of the high luminosity LHC. 

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5. Measurement of CP violation in B0 → D+D− and $$ {\textrm{B}}_{\textrm{s}}^0 $$ → $$ {\textrm{D}}_{\textrm{s}}^{+}{\textrm{D}}_{\textrm{s}}^{-} $$ decays

   https://doi.org/10.1007/JHEP01(2025)061  

   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 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> A time-dependent, flavour-tagged measurement ofCPviolation is performed withB⁰→ D⁺D⁻and$$ {B}_s^0 $$ $B_s^0$ →$$ {D}_s^{+}{D}_s^{-} $$ $D_s^{+}{D}_s^{-}$ decays, using data collected by the LHCb detector in proton-proton collisions at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 6 fb⁻¹. InB⁰→ D⁺D⁻decays theCP-violation parameters are measured to be$$ {\displaystyle \begin{array}{c}{S}_{D^{+}{D}^{-}}=-0.552\pm 0.100\left(\textrm{stat}\right)\pm 0.010\left(\textrm{syst}\right),\\ {}{C}_{D^{+}{D}^{-}}=0.128\pm 0.103\left(\textrm{stat}\right)\pm 0.010\left(\textrm{syst}\right).\end{array}} $$ $\begin{array}{c}{S}_{D^{+}{D}^{-}}=-0.552\pm 0.100\left(\text{stat}\right)\pm 0.010\left(\text{syst}\right),\\ C_{D^{+}{D}^{-}}=0.128\pm 0.103\left(\text{stat}\right)\pm 0.010\left(\text{syst}\right).\end{array}$ In$$ {B}_s^0 $$ $B_s^0$ →$$ {D}_s^{+}{D}_s^{-} $$ $D_s^{+}{D}_s^{-}$ decays theCP-violating parameter formulation in terms ofϕ_sand|λ|results in$$ {\displaystyle \begin{array}{c}{\phi}_s=-0.086\pm 0.106\left(\textrm{stat}\right)\pm 0.028\left(\textrm{syst}\right)\textrm{rad},\\ {}\mid {\lambda}_{D_s^{+}{D}_s^{-}}\mid =1.145\pm 0.126\left(\textrm{stat}\right)\pm 0.031\left(\textrm{syst}\right).\end{array}} $$ $\begin{array}{c}{\varphi }_s=-0.086\pm 0.106\left(\text{stat}\right)\pm 0.028\left(\text{syst}\right)\mathrm{rad},\\ \mid {\lambda }_{D_s^{+}{D}_s^{-}}\mid =1.145\pm 0.126\left(\text{stat}\right)\pm 0.031\left(\text{syst}\right).\end{array}$ These results represent the most precise single measurement of theCP-violation parameters in their respective channels. For the first time in a single measurement,CPsymmetry is observed to be violated inB⁰→ D⁺D⁻decays with a significance exceeding six standard deviations. 

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