### $${B_s^0}$$ B s 0 – $${\bar{B}}_s^0$$ B ¯ s 0 mixing within minimal flavor-violating two-Higgs-doublet models

The European Physical Journal C Springer Science and Business Media LLC 75:12 (2015) 594

#### Authors:

Qin Chang, Pei-Fu Li, Xin-Qiang Li

### Mixing and CP violation in D-0 -> K-pi(+) decays

JOURNAL OF HIGH ENERGY PHYSICS (2022) ARTN 162

#### Authors:

Tommaso Pajero, Michael Joseph Morello

### Analysis of Neutral B-Meson Decays into Two Muons.

Physical review letters 128:4 (2022) 041801

#### Abstract:

Branching fraction and effective lifetime measurements of the rare decay B_{s}^{0}→μ^{+}μ^{-} and searches for the decays B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ are reported using proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a luminosity of 9  fb^{-1}. The branching fraction B(B_{s}^{0}→μ^{+}μ^{-})=(3.09_{-0.43-0.11}^{+0.46+0.15})×10^{-9} and the effective lifetime τ(B_{s}^{0}→μ^{+}μ^{-})=2.07±0.29±0.03  ps are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B^{0}→μ^{+}μ^{-} and B_{s}^{0}→μ^{+}μ^{-}γ decays is found and upper limits B(B^{0}→μ^{+}μ^{-})<2.6×10^{-10} and B(B_{s}^{0}→μ^{+}μ^{-}γ)<2.0×10^{-9} at the 95% C.L. are determined, where the latter is limited to the range m_{μμ}>4.9  GeV/c^{2}. The results are in agreement with the standard model expectations.

### Mixing and $CP$ violation in $D^0 \to K^- π^+$ decays

ArXiv 2106.02014 (2021)

#### Authors:

Tommaso Pajero, Michael Joseph Morello

#### Abstract:

We review the experimental methods to measure mixing and time-dependent $C\!P$ violation in $D^0$ decays into two hadrons. While these phenomena are usually neglected for $D^0 \to K^- \pi^+$ decays, this approximation is not always justified. In particular, it produces a bias on the measurement of the parameter $y_{CP}$, when this is performed by relying on $D^0 \to K^- \pi^+$ decays as a normalisation channel, whose size is around 40% of the precision of the current world average. Finally, we estimate the sensitivity to the weak mixing phases achievable by studying $D^0 \to K^- \pi^+$ and untagged $D \to K^- \pi^+$ decays, where $D$ stands for either of the $D^0$ and $\bar{D}^0$ mesons. Contrary to Cabibbo-suppressed $D^0 \to h^+ h^-$ decays, these decay channels allow to measure these phases without final-state dependent nuisance contributions from the decay amplitudes, but their sensitivity is lower by a factor of six.

### Search for time-dependent $CP$ violation in $D^0 \to K^+ K^-$ and $D^0 \to π^+ π^-$ decays

ArXiv 2105.09889 (2021)

#### Authors:

A search for time-dependent violation of the charge-parity symmetry in $D^0 \to K^+ K^-$ and $D^0 \to \pi^+ \pi^-$ decays is performed at the LHCb experiment using proton-proton collision data recorded from 2015 to 2018 at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb$^{-1}$. The $D^0$ meson is required to originate from a $D^*(2010)^+ \to D^0 \pi^+$ decay, such that its flavour at production is identified by the charge of the accompanying pion. The slope of the time-dependent asymmetry of the decay rates of $D^0$ and $\bar{D}^0$ mesons into the final states under consideration is measured to be $\Delta Y_{K^+ K^-} = (-2.3 \pm 1.5 \pm 0.3) \times 10^{-4}$, $\Delta Y_{\pi^+ \pi^-} = (-4.0 \pm 2.8 \pm 0.4)\times 10^{-4}$, where the first uncertainties are statistical and the second are systematic. These results are compatible with the conservation of the charge-parity symmetry at the level of 2 standard deviations and improve the precision by nearly a factor of two.