Test of local realism via entangled $$\Lambda \bar{\Lambda }$$ system
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Science & Technology - Other Topics↗
Engineering topics
Cheng, W.
Publications and source records attributed to Cheng, W..
Extracting the femtometer structure of strange baryons using the vacuum polarization effect
Abstract One of the fundamental goals of particle physics is to gain a microscopic understanding of the strong interaction. Electromagnetic form factors quantify the structure of hadrons in terms of charge and magnetization distributions. While the nucleon structure has been investigated extensively, data on hyperons are still scarce. It has recently been demonstrated that electron-positron annihilations into hyperon-antihyperon pairs provide a powerful tool to investigate their inner structure. We present a method useful for hyperon-antihyperon pairs of different types which exploits the cross section enhancement due to the effect of vacuum polarization at theJ/ψresonance. Using the 10 billionJ/ψevents collected with the BESIII detector, this allows a precise determination of the hyperon structure function. The result is essentially a precise snapshot of the$$\bar{\Lambda }{\Sigma }^{0}\,(\Lambda {\bar{\Sigma }}^{0})$$ Λ ¯ Σ 0 ( Λ Σ ¯ 0 ) transition process, encoded in the transition form factor ratio and phase. Their values are measured to beR = 0.860 ± 0.029(stat.) ± 0.015(syst.),$$\Delta {\Phi }_{\bar{\Lambda }{\Sigma }^{0}}=(1.011\pm 0.094({{\rm{stat.}}})\pm 0.010({{\rm{syst.}}}))\,{{\rm{r}}}ad$$ Δ Φ Λ ¯ Σ 0 = ( 1.011 ± 0.094 ( stat. ) ± 0.010 ( syst. ) ) r a d and$$\Delta {\Phi }_{\Lambda {\bar{\Sigma }}^{0}}=(2.128\pm 0.094({{\rm{stat.}}})\pm 0.010({{\rm{syst.}}}))\,{{\rm{r}}}ad$$ Δ Φ Λ Σ ¯ 0 = ( 2.128 ± 0.094 ( stat. ) ± 0.010 ( syst. ) ) r a d . Furthermore, charge-parity (CP) breaking is investigated in this reaction and found to be consistent with CP symmetry.
Science & Technology - Other Topics↗
Observation of the semileptonic decays $$ {\textrm{D}}^0\to {\textrm{K}}_{\textrm{S}}^0{\pi}^{-}{\pi}^0{\textrm{e}}^{+}{\nu}_{\textrm{e}} $$ and $$ {\textrm{D}}^{+}\to {\textrm{K}}_{\textrm{S}}^0{\pi}^{+}{\pi}^{-}{\textrm{e}}^{+}{\nu}_{\textrm{e}} $$
Abstract By analyzinge + e − annihilation data corresponding to an integrated luminosity of 2.93 fb −1 collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, the first observation of the semileptonic decays$$ {D}^0\to {K}_S^0{\pi}^{-}{\pi}^0{e}^{+}{\nu}_e $$ D 0 → K S 0 π − π 0 e + ν e and$$ {D}^{+}\to {K}_S^0{\pi}^{+}{\pi}^{-}{e}^{+}{\nu}_e $$ D + → K S 0 π + π − e + ν e is reported. In the hypothesis that all events correspond toK 1 (1270) decays, the branching fractions are measured to be$$ \mathcal{B}\left({D}^0\to {K}_1{(1270)}^{-}\left(\to {K}_S^0{\pi}^{-}{\pi}^0\right){e}^{+}{\nu}_e\right)=\left({1.69}_{-0.46}^{+0.53}\pm 0.15\right)\times {10}^{-4} $$ B D 0 → K 1 1270 − → K S 0 π − π 0 e + ν e = 1.69 − 0.46 + 0.53 ± 0.15 × 10 − 4 and$$ \mathcal{B}\left({D}^{+}\to {\overline{K}}_1{(1270)}^0\left(\to {K}_S^0{\pi}^{+}{\pi}^{-}\right){e}^{+}{\nu}^e\right)=\left({1.47}_{-0.40}^{+0.45}\pm 0.14\right)\times {10}^{-4} $$ B D + → K ¯ 1 1270 0 → K S 0 π + π − e + ν e = 1.47 − 0.40 + 0.45 ± 0.14 × 10 − 4 with statistical significance of 5.4σand 5.6σ, respectively. When combined with measurements of theK 1 (1270)→ K + π − πdecays, the absolute branching fractions are determined to be$$ \mathcal{B}\left({D}^0\to {K}_1{(1270)}^{-}{e}^{+}{\nu}_e\right)=\left({1.08}_{-0.13-0.10}^{+0.14+0.08}\pm 0.21\right)\times {10}^{-3} $$ B D 0 → K 1 1270 − e + ν e = 1.08 − 0.13 − 0.10 + 0.14 + 0.08 ± 0.21 × 10 − 3 and$$ \mathcal{B}\left({D}^{+}\to {\overline{K}}_1{(1270)}^0{e}^{+}{\nu}_e\right)=\left({1.70}_{-0.23}^{+0.26}\pm 0.13\pm 0.35\right)\times {10}^{-3} $$ B D + → K ¯ 1 1270 0 e + ν e = 1.70 − 0.23 + 0.26 ± 0.13 ± 0.35 × 10 − 3 . The first and second uncertainties are statistical and systematic, respectively, and the third uncertainties originate from the assumed branching fractions of theK 1 (1270)→ Kππdecays.
Physics↗
Measurement of e+e− → ωη′ cross sections at $$ \sqrt{s} $$ = 2.000 to 3.080 GeV
Abstract We measured the Born cross sections for the processe + e − →ωη′ at 22 center-of-mass energies from 2.000 to 3.080 GeV with the BESIII detector at the BEPCII collider. We observed a resonant structure with a statistical significance of 9.6σ. A Breit-Wigner fit determines its mass to beM R = (2153±30±31) MeV/c 2 and its width to be Γ R = (167±77±7) MeV, where the first uncertainties are statistical and the second are systematic.
Physics↗
A new learning strategy for the two-time-scale neural controller with its application to the tracking control of rigid arms
A novel fast learning rule with fast weight identification is proposed for the two-time-scale neural controller, and a two-stage learning strategy is developed for the proposed neural controller. The results of the stability analysis show that both the tracking error and the fast weight error will be uniformly bounded and converge to a bounded region which depends only on the accuracy of the slow learning if the system is sufficiently excited. The efficiency of the two-stage learning is also demonstrated by a simulation of a two-link arm.
Cheng, W.↗