Evolution of Edge States and Critical Phenomena in the Rashba Superconductor with Magnetization

We study Andreev bound states (ABS) and resulting charge transport of Rashba superconductor (RSC) where two-dimensional semiconductor (2DSM) heterostructures is sandwiched by spin-singlet s-wave superconductor and ferromagnet insulator. ABS becomes a chiral Majorana edge mode similar to that in spinless chiral p-wave pairing in topological phase (TP). We clarify that two types of quantum criticality about the topological change of ABS near a quantum critical point (QCP), whether ABS exists at QCP or not. In the former type, ABS has a energy gap and does not cross at zero energy in non-topological phase (NTP). These complex properties can be detected by tunneling conductance between normal metal / RSC junctions.Comment: 5 pages, 6 figure

A comparative study of optical/ultraviolet variability of narrow-line Seyfert 1 and broad-line Seyfert 1 active galactic nuclei

The ensemble optical/ultraviolet variability of narrow-line Seyfert 1 (NLS1) type active galactic nuclei (AGNs) is investigated, based on a sample selected from the Sloan Digital Sky Survey (SDSS) Stripe-82 region with multi-epoch photometric scanning data. As a comparison a control sample of broad-line Seyfert 1 (BLS1) type AGNs is also incorporated. To quantify properly the intrinsic variation amplitudes and their uncertainties, a novel method of parametric maximum-likelihood is introduced, that has, as we argued, certain virtues over previously used methods. The majority of NLS1-type AGNs exhibit significant variability on timescales from about ten days to a few years with, however, on average smaller amplitudes compared to BLS1-type AGNs. About 20 NLS1- type AGNs showing relatively large variations are presented, that may deserve future monitoring observations, for instance, reverberation mapping. The averaged structure functions of variability, constructed using the same maximumlikelihood method, show remarkable similarity in shape for the two types of AGNs on timescales longer than about 10 days, which can be approximated by a power-law or an exponential function. This, along with other similar properties, such as the wavelength-dependent variability, are indicative of a common dominant mechanism responsible for the long-term optical/UV variability of both NLS1- and BLS1-type AGNs. Towards the short timescales, however, there is tentative evidence that the structure function of NLS1-type AGNs continues declining, whereas that of BLS1-type AGNs flattens with some residual variability on timescales of days. If this can be confirmed, it may suggest that an alternative mechanism, such as X-ray reprocessing, starts to become dominating in BLS1-type AGNs, but not in NLS1-, on such timescales.Comment: 53 pages, 13 figures, 3 tables, accepted for pulication in A

P2-type Na2/3Ni1/3Mn2/3O2 Cathode Material with Excellent Rate and Cycling Performance for Sodium-Ion Batteries

P2-type Na2/3Ni1/3Mn2/3O2 is an air-stable cathode material for sodium-ion batteries. However, it suffers irreversible P2-O2 phase transition in 4.2-V plateau and shows poor cycling stability and rate capability within this plateau. To evaluate the practicability of this material in 2.3–4.1 V voltage range, single-crystal micro-sized P2-type Na2/3Ni1/3Mn2/3O2 with high rate capability and cycling stability is synthesized via polyvinylpyrrolidone (PVP)-combustion method. The electrochemical performance is evaluated by galvanostatic charge-discharge tests. The kinetics of Na+ intercalation/deintercalation is studied detailly with potential intermittent titration technique (PITT), galvanostatic intermittent titration technique (GITT) and cyclic voltammetry (CV). The discharge capacity at 0.1 C in 2.3–4.1 V is 87.6 mAh g−1. It can deliver 91.5% capacity at 40 C rate and keep 89% after 650 cycles at 5C. The calculated theoretical energy density of full cell with hard carbon anode is 210 Wh kg−1. The moderate energy density associated with high power density and long cycle life is acceptable for load adjustment of new-energy power, showing the prospect of practical application

Measurement of the branching fraction for ψ(3770) → γχc0

By analyzing a data set of 2.92 fb−12.92 fb−1 of e+e−e+e− collision data taken at View the MathML sources=3.773 GeV and 106.41×106106.41×106ψ(3686)ψ(3686) decays taken at View the MathML sources=3.686 GeV with the BESIII detector at the BEPCII collider, we measure the branching fraction and the partial decay width for ψ(3770)→γχc0ψ(3770)→γχc0 to be B(ψ(3770)→γχc0)=(6.88±0.28±0.67)×10−3B(ψ(3770)→γχc0)=(6.88±0.28±0.67)×10−3 and Γ[ψ(3770)→γχc0]=(187±8±19) keVΓ[ψ(3770)→γχc0]=(187±8±19) keV, respectively. These are the most precise measurements to date

Amplitude analysis of the decays η′→π+π−π0 and η′→π0π0π0

Based on a sample of 1.31×109  J/ψ events collected with the BESIII detector, an amplitude analysis of the isospin-violating decays η′→π+π−π0 and η′→π0π0π0 is performed. A significant P-wave contribution from η′→ρ±π∓ is observed for the first time in η′→π+π−π0. The branching fraction is determined to be B(η′→ρ±π∓)=(7.44±0.60±1.26±1.84)×10−4, where the first uncertainty is statistical, the second systematic, and the third model dependent. In addition to the nonresonant S-wave component, there is a significant σ meson component. The branching fractions of the combined S-wave components are determined to be B(η′→π+π−π0)S=(37.63±0.77±2.22±4.48)×10−4 and B(η′→π0π0π0)=(35.22±0.82±2.54)×10−4, respectively. The latter one is consistent with previous BESIII measurements

Dark photon search in the mass range between 1.5 and 3.4 GeV/c2

Using a data set of 2.93 fb−1 taken at a center-of-mass energy s=3.773 GeV with the BESIII detector at the BEPCII collider, we perform a search for an extra U(1) gauge boson, also denoted as a dark photon. We examine the initial state radiation reactions e+e−→e+e−γISR and e+e−→μ+μ−γISR for this search, where the dark photon would appear as an enhancement in the invariant mass distribution of the leptonic pairs. We observe no obvious enhancement in the mass range between 1.5 and 3.4 GeV/c2 and set a 90% confidence level upper limit on the mixing strength of the dark photon and the Standard Model photon. We obtain a competitive limit in the tested mass range

Improved measurements of branching fractions for ηc →φφ and ωφ

Using ð223.7 1.4Þ × 106 J=ψ events accumulated with the BESIII detector, we study ηc decays to ϕϕ and ωϕ final states. The branching fraction of ηc → ϕϕ is measured to be Brðηc → ϕϕÞ ¼ ð2.5 0.3þ0.3 −0.7 0.6Þ × 10−3, where the first uncertainty is statistical, the second is systematic, and the third is from the uncertainty of BrðJ=ψ → γηcÞ. No significant signal for the double Okubo-Zweig-Iizuka suppressed decay of ηc → ωϕ is observed, and the upper limit on the branching fraction is determined to be Brðηc → ωϕÞ < 2.5 × 10−4 at the 90% confidence level

Measurement of the branching fractions of Ds+→η'X and Ds+→η'ρ+ in e+e-→Ds+Ds-

We study D+s decays to final states involving the η with a 482 pb−1 data sample collected at √s = 4.009 GeV with the BESIII detector at the BEPCII collider. We measure the branching fractionsB(D+s →η X) = (8.8 ± 1.8 ± 0.5)% and B(D+s →ηρ+) = (5.8 ± 1.4 ± 0.4)% where the first uncertainty is statistical and the second is systematic. In addition, we estimate an upper limit on the non-resonant branching ratio B(D+s →ηπ+π0) < 5.1% at the 90% confidence level. Our results are consistent with CLEO’s recent measurements and help to resolve the disagreement between the theoretical prediction and CLEO’s previous measurement of B(D+s →ηρ+)

An improved limit for Γee of X(3872) and Γee measurement of ψ(3686)

Using the data sets taken at center-of-mass energies above 4 GeV by the BESIII detector at the BEPCII storage ring, we search for the reaction e+e- -> gamma_ISR X(3872) -> gamma_ISR pi+pi-J/psi via the Initial State Radiation technique. The production of a resonance with quantum numbers J^PC = 1^++ such as the X(3872) via single photon e+e- annihilation is forbidden, but is allowed by a next-to-leading order box diagram. We do not observe a significant signal of X(3872), and therefore give an upper limit for the electronic width times the branching fraction Gamma_ee^X(3872)Br(X(3872) -> pi+pi-Jpsi) < 0.13 eV at the 90% confidence level. This measurement improves upon existing limits by a factor of 46. Using the same final state, we also measure the electronic width of the psi(3686) to be Gamma_ee^psi(3686) = 2231 +- 18 +- 99 eV