arXiv subjects
Publications and source records attributed to Daiki Ueda.
We study nuclear electric dipole moments induced by $ΔF=1$ effective operators in the Standard Model Effective Field Theory. Such contributions arise through renormalization group evolutions and matching conditions at the electroweak symmetry breaking scale. We provide one-loop formulae for the matching conditions. We also discuss correlations of these effects with $ΔF=2$ observables such as $ε_K$ and $ΔM_{B_d}$.
We investigate a weak measurement described by a von Neumann type interaction $\hat{A}\otimes \hat{p}^2$, where $\hat{A}$ is a system observable and $\hat{p}^2$ is a measurement pointer observable. We consider the weak measurement in terms of thermodynamics by adopting a mixed Gaussian state as a quantum state of the measurement pointer. We show that Maxwell's demon appears as a measure who carries out post-selections. It is found that, even if the demon only knows the weak value, a difference in the von Neumann entropy between the initial and final system can be the QC mutual information contents, which is the maximum amount of obtainable information by a measurement. Besides, our study indicates that a temperature of the system described by this interaction is amplified by weak value amplification. In addition, we show that this demon can be realized in an atomic system.
We investigate model independent top-quark corrections to $ΔF = 2$ processes for the down-type quarks within the framework of the Standard Model Effective Field Theory. Dimension-six $ΔF = 1$ operators contribute to them through renormalization group evolutions and matching conditions. We provide a complete one-loop matching formula from the top quarks for $ΔF=2$ transitions. We also demonstrate these corrections on $ΔM_{B_s}$ in the left-right symmetric model, which are compared with the conventional calculation.
We investigate the heat capacity of liquids through a theoretical approach based on a quasiparticle description. By interpreting the microscopic dynamics of particles in liquids in terms of quasiparticles, we suggest a simplified understanding of the number of degrees of freedom in liquids. A equivalence between hydrodynamics and U(1) gauge theory, which is newly proposed in the present paper, develops the quasiparticle description to construct a new Lagrangian which correctly reproduces the number of modes at the melting points and at the critical points. The heat capacity evaluated from this Lagrangian naturally interpolates between these two points, and agrees with the phonon theory of liquids [Sci. Rep. 2, 421 (2012)].
We investigate a new experimental possibility of measuring the Newtonian gravitational constant $G$ by using the weak measurement. Amplification via weak measurement is one of the interesting phenomena of quantum mechanics. In this letter, we consider it in a system consisting of many cold atoms which are gravitationally interacting with an external macroscopic source and show that it is possible to obtain ${\mathcal{O}}(10^{3})$ amplification of their relative motion compared with the classical motion when the number of atoms are ${\mathcal{O}}(10^{15})$ and the observing time is $\sim 0.5$s. This result suggests that it might be possible to use this system as a new experimental set up for determining $G$. Besides, our study indicates that the gravitational force can behave as a repulsive force because of the weak measurement.
In light of a discrepancy of the direct $CP$ violation in $K\toππ$ decays, $\varepsilon'/\varepsilon_K$, we investigate gluino contributions to the electroweak penguin, where flavor violations are induced by squark trilinear couplings. Top-Yukawa contributions to $ΔS = 2$ observables are taken into account, and vacuum stability conditions are evaluated in detail. It is found that this scenario can explain the discrepancy of $\varepsilon'/\varepsilon_K$ for the squark mass smaller than 5.6 TeV. We also show that the gluino contributions can amplify $\mathcal{B}(K \to πν\overlineν)$, $\mathcal{B}(K_S \to μ^+ μ^-)_{\rm eff}$ and $ΔA_{\rm CP}(b\to sγ)$. Such large effects could be measured in future experiments.
Recently, the standard model prediction of $ε'/ε$ was improved, and a discrepancy from the experimental results was reported at the $2.9σ$ level. We study the chargino contributions to $Z$ penguin especially with the vacuum stability constraint. The vacuum decay rate is investigated, and it is shown that the discrepancy can be explained if superparticles are lighter than 4-6 TeV. Correlations with $\mathcal{B}(K_L\toπ^0ν\barν)$ and other experimental constraints are also discussed.