0000000000423361
AUTHOR
C. Cheng
showing 3 related works from this author
Search for Production of Invisible Final States in Single-Photon Decays of Υ(1S)
2010
We search for single-photon decays of the Upsilon(1S) resonance, Upsilon->gamma+invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A0, or a pair of dark matter particles, chi chi-bar. Both A0 and chi are assumed to have zero spin. We tag Upsilon(1S) decays with a dipion transition Upsilon(2S)->pi+pi-Upsilon(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m_A0<=9.2 GeV and m_chi<=4.5 GeV in the sample of 98e6 Upsilon(2S) decays collected with the BaBar detector and set stringent limits on new physics models that contain light dark ma…
First Evidence of Axial Shape Asymmetry and Configuration Coexistence in 74Zn : Suggestion for a Northern Extension of the N = 40 Island of Inversion
2023
The excited states of N=44 74Zn were investigated via γ-ray spectroscopy following 74Cu β decay. By exploiting γ−γ angular correlation analysis, the 2+2, 3+1, 0+2, and 2+3 states in 74Zn were firmly established. The γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2+2, 3+1, and 2+3 states were measured, allowing for the extraction of relative B(E2) values. In particular, the 2+3→0+2 and 2+3→4+1 transitions were observed for the first time. The results show excellent agreement with new microscopic large-scale shell-model calculations, and are discussed in terms of underlying shapes, as well as the role of neutron excitations across the N=40 gap. Enhanced axial shape asy…
First Evidence of Axial Shape Asymmetry and Configuration Coexistence in $^{74}$Zn: Suggestion for a Northern Extension of the $N=40$ Island of Inver…
2023
International audience; The excited states of $N=44$$^{74}$Zn were investigated via $\gamma$-ray spectroscopy following $^{74}$Cu $\beta$ decay. By exploiting $\gamma$-$\gamma$ angular correlation analysis, the $2_2^+$, $3_1^+$, $0_2^+$ and $2_3^+$ states in $^{74}$Zn were firmly established. The $\gamma$-ray branching and $E2/M1$ mixing ratios for transitions de-exciting the $2_2^+$, $3_1^+$ and $2_3^+$ states were measured, allowing for the extraction of relative $B(E2)$ values. In particular, the $2_3^+ \to 0_2^+$ and $2_3^+ \to 4_1^+$ transitions were observed for the first time. The results show excellent agreement with new microscopic large-scale shell-model calculations, and are disc…