The E1 and E2 capture amplitudes in 12C(α,γ0)16O

Excitation functions of the %₀ capture transition in ¹²C(!,%)¹⁶O at /_% = 90^§ were obtained using a 4 2 4' BGO crystal in close geometry (E = 0.94 to 3.39 MeV) and a 2 2 2' BGO crystal in far geometry (E = 1.69 to 3.29 MeV), where the study of the reaction was initiated in inverse kinematics involving a windowless gas target. The small crystal detected essentially the E1 multipole component in the %₀ capture transition, while the large crystal observed approximately the angle-integrated sum of the E1 and E2 multipole components. Analysis of the two data sets together with data from previous work provided strong evidence that both multipoles are of equal importance at the relevant stellar energy E₀ = 0.3 MeV.     

Fundamental absorption of calcium,magnesium, and lithium fluorides in the range of 8–12 μm

The fundamental absorption of calcium, magnesium, and lithium fluorides in the range of 8–12 μm has been studied experimentally by the spectrophotometric method. The known and experimentally obtained values of the absorption coefficients of these materials have been analyzed. It has been shown that the values experimentally measured in the range of 8–12 μm obey the Uhrbach rule and the multiphoton absorption determines the long-wavelength transmission cutoff of pure optical materials. The results presented make it possible to suggest that plates made of LiF and CaF₂ crystals and of optical ceramics based on MgF₂ can be used to fabricate calibrated radiation attenuators in the spectral range of 8–12 μm.     

Optical lattice trapping of 199Hg and determination of the magic wavelength for the ultraviolet 1S(0)↔3P(0) clock transition

We report on the Lamb-Dicke spectroscopy of the doubly forbidden (6s(2))(1)S(0)?(6s6p)(3)P(0) transition in (199)Hg atoms confined to a vertical 1D optical lattice. With lattice trapping of ?10(3) atoms and a 265.6 nm probe laser linked to the LNE-SYRTE primary frequency reference we have determined the center frequency of the transition for a range of lattice wavelengths and at two lattice trap depths. We find the Stark-free (magic) wavelength to be 362.53(0.21) nm-essential knowledge for future use of this line in a clock with anticipated 10(-18) range accuracy. We also present evidence of the laser excitation of a Wannier-Stark ladder of states in a lattice of well depth 10E(R).     

Electron Impact Excitations and Linear Polarization for 1s2 1S0-1s2p3,1P1 Lines of Fe24＋ Ions under Screened Coulomb Interactions

Electron impact excitation cross sections from the ground state to the individual magnetic sublevels of 1s2p 3＇1P1 states in high-temperature dense plasmas are calculated for highly charged He-like Fe24＋ ions by using a fully relativistic distorted-wave method. The Debye-Huckel screening model is used to screen the projectile electron from the nucleus and target electrons. The linear polarization degrees for these lines are obtained. It is found that the cross sections at all incident energies decrease with the increase of the screening for these excitations. The influence of screening on linear polarization degrees of the 1P1 line is very small. The linear polarization degrees of aP1 line decrease sharply at low incident energy with the increase of the screening.     

Measurement of the relative probability of the decay φ → η′γ in the channel η′ → ηπ0π0, η → γγ

The process e ⁺ e ^? → η′γ, η′ → η π⁰π⁰, η → γγ is investigated by an SND detector in experiment on a VEPP-2M equipment with colliding electron-positron beams. The analysis of experimental data yields a value of B(? → η′γ)=(6.7 _?4.2 ^+5.0 ±1.5)×10^?5 for the decay probability. Taking into account a previous measurement of this quantity by an SND detector in the decay channel η′ → π⁺π^?η, one finally obtains B(?→η ′γ)=(6.7 _?2.4 ^+2.8 ±0.8)×10^?5.     

Classical Projections of Quantum Mechanics and the Limit ħ → 0

The convergence of the dynamics of classical projection to the dynamics of the classical limit is investigated for 0. A mistake from a previous paper is pointed out, and the correct version of the result is given. A new, similar result is presented if the function generating the Hamiltonian of both the classical projection and the classical limit is a polynomial.     

A new upper limit for the branching ratio of the decay K0S → e+e−

A new value of the upper limit for the branching ratio of the decay of K⁰_S into e⁺e⁻ has been experimentally obtained using a lead glass detector. The value is BR (K⁰_S → e⁺e⁻) < 1.1 × 10⁻⁴ (90% CL).     

Theoretical study of stereodynamics for the D'+ DS(v=0,j=0) → D'D + S abstraction reaction

Quasiclassical trajectory (QCT) calculations have been performed for the abstraction reaction, D'+ DS(v = 0, j = 0) → D'D + S on a new LZHH potential energy surface (PES) of the adiabatic 3 A electronic state [Lü et al. 2012 J. Chem. Phys. 136 094308]. The collision energy effect on the integral cross section and product polarization are studied over a wide collision energy range from 0.1 to 2.0 eV. The cross sections calculated by the QCT procedure are in good accordance with previous quantum wave packet results. The three angular distribution functions, P(θr), P(φr), and P(θr,φr), together with the four commonly used polarization-dependent differential cross sections ((2π/σ)(dσ00/dωt), (2π/σ)(dσ20/dωt), (2π/σ)(dσ22+/dωt), (2π/σ)(dσ21/dωt)) are obtained to gain insight into the chemical stereodynamics of the title reaction. Influences of the collision energy on the product polarization are exhibited and discussed.     

Measurement of the cross section for the e + e ? → ωπ0 → π0π0γ process in the energy range of 1.1–1.9 GeV

The cross section for the e ⁺ e ^? ?? ???⁰ ?? ??⁰??⁰?? process has been measured in the energy range of 1.1?C1.9 GeV. The measurement has been made with the Spherical Neutral Detector at the VEPP-2000 e ⁺ e ^? collider. The data in the energy range of 1.1?C1.4 GeV are in agreement with the earlier measurements with the SND and CMD-2 detectors. The cross section has also been measured above 1.4 GeV.     

Tetraquark-based analysis and predictions of the cross sections and distributions for the processes e+e-→Υ(1S)(π+π-,K+K-,ηπ0) near Υ(5S)

We calculate the cross sections and final state distributions for the processes e(+)e(-)→Υ(1S)×(π(+)π(-),K(+)K(-),ηπ(0)) near the Υ(5S) resonance based on the tetraquark hypothesis. This framework is used to analyze the data on the Υ(1S)π(+)π(-) and Υ(1S)K(+)K(-) final states [K.?F. Chen et al. (Belle Collaboration), Phys. Rev. Lett. 100, 112001 (2008); I. Adachi et al. (Belle Collaboration), Phys. Rev. D 82, 091106 (2010).], yielding good fits. Dimeson invariant-mass spectra in these processes are shown to be dominated by the corresponding light scalar and tensor states. The resulting correlations among the cross sections are worked out. We also predict σ(e(+)e(-)→Υ(1S)K(+)K(-))/σ(e(+)e(-)→Υ(1S)K(0)K(0))=1/4. These features provide crucial tests of the tetraquark framework and can be searched for in the currently available and forthcoming data from the B factories.     

Weak- and hyperfine-interaction-induced 1s2s ~1S_0→ 1s~2 ~1S_0 E1 transition rates of He-like ions

Weak- and hyperfine-interaction-induced 1s2s1S0→ 1s2 1S0E1 transition rates for the isoelectronic sequence of Helike ions have been calculated using the multi-configuration Dirac–Hartree–Fock(MCDHF) and relativistic configuration interaction methods. The results should be helpful for the future experimental investigations of parity non-conservation effects.     

Study of Exclusive Hadronic Decays for D0→Ks0π+π- and D0→Ks0K+K- and Their Resonant Structures

We report the results of an experimental study of the exclusive hadronic decays for D0→K0 sπ+π - and K 0 sK +K - and their resonant structures using BES-Ⅰ detector at the BEPC Collider. Using the data sample of 22.3 pb -1 collected at the center-of-mass energy s=4.03 GeV, we measured the branching fraction for D 0→K 0π +π - to be (5.32±0.53±0.40)%, the branching fractions for the decays D 0→ K *-π +, D 0→K 0ρ 0 and D 0→K 0(π +π -) non-resonant to be (6.05±0.32±0.49)%, (1.17±0.17±0.13)% and (1.35±0.22±0.17)%, respectively. We measured the branching fractions Br(D 0→f) to be (1.04±0.24± 0.16)% for f=K 0K +K -, (1.12±0.34±0.15)% for f=K0, and (0.27±0.13±0.03)% for f=K 0(K+K-)non-.     

TheK S 0 →π0 l + l − andK L 0 →π0 l + l − decays in the standard model and the extended Nambu-Jona-Lasinio model

TheK _S ^{0 0} l ⁺ l ^– andK _L ^{0 0} l ⁺ l ^– decays are considered within the framework of the Standard model in the one-photon exchange approximation, i.e.K _S,L ^{0 0}+ *⁰ +l ⁺ l ^–. To evaluate the low-energy matrix elements of theK ⁰(¯K ⁰)⁰+ * transitions, the constituentquark-loop approximation, based on the extended Nambu-Jona-Lasino (NJL) model, is used. The obtained results are compared with other theoretical estimates and the experimental bounds.     

Evidence for direct CP violation in B±→ηh± and observation of B0→ηK0

We report measurements of the branching fractions and CP asymmetries for B(±)→ηh(±) (h=K or π) and the observation of the decay B(0)→ηK(0) from the final data sample of 772×10(6) B ?B pairs collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. The measured branching fractions are B(B(±)→ηK(±))=(2.12±0.23±0.11)×10(-6), B(B(±)→ηπ(±))=(4.07±0.26±0.21)×10(-6), and B(B(0)→ηK(0))=(1.27(-0.29)(+0.33)±0.08)×10(-6), where the last decay is observed for the first time with a significance of 5.4 standard deviations (σ). We also find evidence for CP violation in the charged B modes, A(CP)(B(±)→ηK(±))=-0.38±0.11±0.01 and A(CP)(B(±)→ηπ(±))=-0.19±0.06±0.01 with significances of 3.8 σ and 3.0 σ, respectively. For all measurements, the first and second uncertainties are statistical and systematic, respectively.