Sneha Malde

Abstract:

A first determination of the strong-phase difference between $D^0$ and $\overline{D^0}\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ is performed using $e^{+}{e}^{-}\to \psi (3770)\to D\overline{D}$ data collected by the BESIII detector corresponding to an integrated luminosity of $20.3{\mathrm{fb}}^{-1}$ . The measurements are made in four pairs of bins in phase space, which are chosen to provide optimal sensitivity to the angle $\gamma$ of the unitarity triangle in $B^{\pm }\to D{K}^{\pm }$ decays. From these measurements, it follows that the $CP$ -even fraction of the decay is $F_{+}=0.754\pm 0.010_{\mathrm{stat}}\pm 0.008_{\mathrm{syst}}$ . In addition, the branching fraction of $D^0\to K^{+}{K}^{-}{\pi }^{+}{\pi }^{-}$ is measured to be $(2.863\pm 0.028_{\mathrm{stat}}\pm 0.045_{\mathrm{syst}})\times {10}^{-3}$ , which is twice as precise as previous results obtained at other experiments. Published by the American Physical Society 2025

Abstract:

Utilizing 4.5 of annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider, we searched for singly Cabibbo-suppressed hadronic decays and with a single-tag method. No significant signals were observed for both decays. The upper limits on the branching fractions at the 90% confidence level were determined to be for and for .

Abstract:

The first observation of the ${\mathrm{\Sigma }}^{+}\to p{\mu }^{+}{\mu }^{-}$ decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of $5.4{\mathrm{fb}}^{-1}$ , collected with the LHCb detector at a center-of-mass energy of 13 TeV. A yield of $237\pm 16{\mathrm{\Sigma }}^{+}\to p{\mu }^{+}{\mu }^{-}$ decays is obtained, where the uncertainty is statistical only. A branching fraction of $(1.08\pm 0.17)\times {10}^{-8}$ is measured, where the uncertainty includes statistical and systematic sources. No evidence of resonant structures is found in the dimuon invariant-mass distribution. All results are compatible with standard model expectations. This represents the rarest decay of a baryon ever observed.

Abstract:

Using a sample of (2.712 ± 0.014) × 109ψ(3686) events collected with the BESIII detector at the electron positron collider BEPCII, the decay ψ(3686) → Ξ−KS0Ω¯+ + c.c. is observed for the first time, which has a significance of 5.9 standard deviations. The branching fraction of this decay is measured to be (2.91 ± 0.47 ± 0.33) × 10−6, where the first and second uncertainties are statistical and systematic, respectively. The ratio between Bψ3686→Ξ−KS0Ω¯++c.c and Bψ3686→Ω−K+Ξ¯0+c.c is determined to be 1.05 ± 0.23 ± 0.14, which deviates from the isospin symmetry conservation predicted value of 0.5 by 2.1σ.