arXiv subjects

Daniel A. López Aguilar

Publications and source records attributed to Daniel A. López Aguilar.

3 recordsLinked to original sources

arXiv2026

CP violation in two meson tau decays

CP violation in $τ\to K_S πν_τ$ decays has attracted a lot of attention recently, due to the BaBar anomaly in the corresponding rate asymmetry. Within an effective field theory formalism, only extreme fine-tuning would allow to understand such measurement, which is currently being scrutinized at Belle(-II), as will be in the future super-charm-tau factory. Here we summarize the results of applying the same formalism to the other two-meson tau decay channels, which can help solve this conundrum. Our main conclusion is that current and future experiments would be sensitive to the maximum allowed CP rate asymmetry in the related $K^\pm K_S$ modes with a measurement having 5$\%$ precision, that will either support or cast further doubts on the BaBar anomaly.

hep-ph↗

arXiv2025

Generalized structure functions in semileptonic tau decays

In case there are tensor interactions beyond the SM in the low-energy effective Lagrangian, their interference with the SM V-A currents yields a contribution for tau decays into three or more mesons that cannot be included in the famous structure functions introduced by Kühn and Mirkes in their seminal 1992 paper. We present this generalization here, highlighting again the importance of measuring the (generalized) spectral functions, as being model-independent and exploiting maximally the data. This can be particularly relevant for CP and T violation studies with at least three mesons in the final state of the tau decay.

hep-ph↗

arXiv2025

CP violation in two-meson Tau decays induced by heavy new physics

We apply the effective field theory formalism that was used to study CP violation induced by heavy new physics in the $τ\to K_S πν_τ$ decays to the other two-meson tau decay channels. We focus on the rate and the forward-backward asymmetries, that are predicted using current bounds on the complex Wilson coefficients of the effective Lagrangian. We discuss our outcomes for the modes with $(K/π)π^0$ and $K K_S$, that can be studied at Belle-II and a super-tau-charm facility. Our main finding is that current and forthcoming experiments would be sensitive to the maximum allowed CP rate asymmetry in the $K^\pm K_S$ modes if a precision of $5\%$ is reached on this observable, that can check as well the BaBar anomaly in $K_Sπ$. For the $π^\pmπ^0$ channels, new physics would be difficult to probe at present. Disentangling new sources of CP violation would be most challenging in $K^\pmπ^0$ and the other modes.

hep-ph↗