Investigation of the narrow structure K(1630) decaying into the K S 0 π+π− system

The narrow structure K(1630) is singled out in the effective-mass spectrum of the K _S ⁰ π⁺π^? system originating from π^? p collisions at 16 GeV/c. This structure is predominantly formed in inelastic collisions accompanied by high momentum transfers. For events from the K(1630) region, kinematical distributions show special features that may be associated with spin manifestations and with correlations between the products arising from the decays of the hypothesized exotic resonance state. Experimental observations of narrow hadronic structures formed at high momentum transfers are reviewed.     

Impurity effects of the Λ hyperon in the hypernuclear systems Λ25Mg and Λ29Si

Based on the beyond-mean-field Skyrme-Hartree-Fock model,impurity effects of the Λ hyperon in the hypernuclear systems Λ25Mg and Λ29Si are investigated,respecti...     

Can the Λ(1405) resonance Be seen in neutron spectra from the K − + d reaction?

Neutron spectra from the low-energy reaction K ^? + d → π +Σ+n were calculated using coupled-channel Faddeev equations. The possibility of tracing the signature of the Λ(1405) resonance in the spectra was investigated for four different phenomenological models describing K? N-πΣ interactions. We found, that while in the direct spectra kinematic effects mask completely the peak corresponding to the resonance, the deviation spectrum method [J. Esmaili et al., Phys. Rev. C 83, 055207 (2011)] is able to eliminate kinematics and differentiate between different models of Λ(1405).     

Modelling of multi-bodies in close proximity under water waves——Fluid resonance in narrow gaps

Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water waves.The numerical results are compared with experimental data available in the literature.The comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the res...     

Polarization of Λ0 hyperons in nucleus-nucleus collisions at high energies

The measurement of Λ⁰-hyperon polarization in nucleus-nucleus collisions is considered as one of possible tools to study the phase transition. Fixed target and collider experiments are discussed for the case of λ⁰ production from Au-Au central collisions at $ \sqrt {s_{NN} } $ of about several GeV.     

Is Bell-type inequality violated for K0-\bar K^0 , B0-\bar B^0 , . . . systems?

We extend the Clauser-Horne formulation of Bell-type inequality for the correlated pair of decaying and oscillating (neutral pseudo-scalar) meson-antimesons, using a few supplementary assumptions. The quantum-mechanical predictions for the B⁰- \(\bar B^0 \) system do lead to violations of this inequality under certain conditions. Further work is called for to investigate the possibility of dispensing with the supplementary assumptions.     

What we can learn from γγ→ππ,K \bar K in the resonance region

The two photon couplings of hadronic states are believed to be key pointers to their parton constitutents. With the aim of studying these, we present a method of analysing data on γγ→ππ (andK \(\bar K\) ), which embodies the constraints of unitarity and analyticity while respecting the QED low energy theorem required by gauge invariance. We apply this analysis to presently available data on ππ production and find that within the existing uncertainties few definitive conclusions can yet be drawn in the resonance region. For instance, even the claim that thef-resonance has a largely helicity two coupling is shown not to be established. We illustrate the importance of the angular dependence of the data to reach almost all conclusions not only on the helicity structure off-production but also on the couplings of the scalar states to this vital channel. In the near threshold region, however, we confirm the overwhelming dominance of the QED Born amplitude modified by final state interactions in contradiction with several recent datasets on the π⁺π^? channel. We show how the new Crystal Ball experiment on π⁺0⁰ production not only confirms this conclusion on the near threshold cross-section but angular analysis of their data with its better statistics using the method we present should shed light on the nature of the scalar mesons in the 1 GeV region.     

The coherent K L 0 C → K S 0 C regeneration at high energies

New experimental results on the coherentK _L ⁰ C K _S ⁰ C regeneration in the momentum range 10p30 GeV/c are presented. For the quantity (f ₀–¯f ₀/k (where f₀ and¯f ₀ are theKC and¯K ⁰C forward scattering amplitudes andk is the wave number) we have obtained: arg (f ₀–¯f ₀)/k=–126±14 and ¦(f ₀–¯f ₀/k¦ p ^{–0.62±0.14} These results are well described by a simple Regge pole model including only the (-trajectory exchange in thet-channel with the intercept (0) close to 0.4.Presented at the IV International Symposium on High Energy and Elementary Particle Physics, Warszaw, September 1975.     

X-ray emission via Kα resonance complexes in gold ions

The excitation energies from ground state for 63 fine structure levels of the terms belonging to 1 s², 1snl, 2lnl′ (n = 2,3), 3l3l′ (l ≠ ≠ l′) configurations of Au⁷⁷⁺, as well as oscillator strengths for electric-dipole-allowed and intercombination transitions among the fine-structure levels were theoretically evaluated. The important relativistic effects in intermediate coupling are incorporated by means of the Breit–Pauli Hamiltonian. Extensive comparisons are performed with several approximations and previous data sets in order to size up contributing effects and to estimate accuracy ratings. The atomic excitation is obtained by electron impact in close coupling approach. For optically allowed transitions, the electron-impact collision strengths at collision energy up to 80 keV are reported. The results are relevant to the laboratory and astrophysical plasmas.     

Study of coherent diffractive production reactions ofp+C→[Y 0 K +]+C type and observation of narrow structures in ∑ (1385)0 K + and ∑0 K + effective mass spectra

In the experiments at the SPHINX facility in 70 GeV proton beam of the IHEP accelerator the coherent diffractive production reactions on carbon nucleip+C [(1385)⁰ K ⁺+C andp+C[⁰ K ⁺]+C were investigated. The evidences for new baryon states were obtained in the study of hyperon-kaon effective mass spectra in these two reactions:X (2050) with massM=(2052±6) MeV and width =(35 _–35 ⁺²² ) MeV inM[(1385)⁰ K ⁺] andX(2000) withM=1999±6 MeV and =91±17 MeV inM[⁰ K ⁺]. The unusual features of these massive states (small enough decay widths, anomalously large branching ratios for decays with strange particles emission) make them very serious candidates for cryptoexotic pentaquark baryons with hidden strangeness.     

Search for CP violation in the decays D(0)→K(S)(0)P(0)

We have searched for CP violation in the decays D(0)→K(S)(0)P(0) where P(0) denotes a neutral pseudoscalar meson that is either a π(0), η, or η' using KEKB asymmetric-energy e(+)e(-) collision data corresponding to an integrated luminosity of 791 fb(-1) collected with the Belle detector. No evidence of significant CP violation is observed. We report the most precise CP asymmetry measurement in the decay D(0)→K(S)(0)π(0) to date: A(CP)(D(0)→K(S)(0)π(0))=(-0.28±0.19±0.10)%. We also report the first measurements of CP asymmetries in the decays D(0)→K(S)(0)η and D(0)→K(S)(0)η': A(CP)(D(0)→K(S)(0)η)=(+0.54±0.51±0.16)% and A(CP)(D(0)→K(S)(0)η')=(+0.98±0.67±0.14)%, respectively.     

Single π~0 electro-production in the resonance region with CLAS

We report the analysis status of single π~0 electroproduction in the resonance region to study the electromagnetic excitation of the nucleon resonances. The study is aimed at understanding of the internal structure and dynamics of the nucleon. The experiment was performed using an unpolarized cryogenic hydrogen target and 2.0 and 5.8 GeV polarized electron beam during the e1e and e1-6 run periods with CLAS at Jefferson Lab. The new measurements will produce a data base with high statistics and large kinematic coverage for the hadronic invariant mass (W) up to 2.0 GeV in the momentum transfer (Q~2) range of 0.3-6.0 GeV~2. Preliminary results will be presented and compared with the various model calculations.     

Splitting of N-type optical resonance formed in Λ-system of 85Rb atoms in a strong transverse magnetic field

We study narrow-band N-type resonance formed in a Λ-system of ⁸⁵Rb atoms. Even when thin (micrometer) optical cells are employed, N-type resonance has a high contrast. We used radiation of two cw diode lasers. Peculiarities of splitting of N-type resonance into six components in a strong transverse magnetic field are studied experimentally and theoretically and the conversion to the Paschen-Back regime on the hyperfine structure of ⁸⁵Rb atoms is recorded.     

Single π0electro-production in the resonance region with CLAS＊

We report the analysis status of single π0electroproduction in the resonance region to study the electromagnetic excitation of the nucleon resonances. The study is aimed at understanding of the internal structure and dynamics of the nucleon. The experiment was performed using an unpolarized cryogenic hydrogen target and 2.0 and 5.8 GeV polarized electron beam during the ele and e1-6 run periods with CLAS at Jefferson Lab. The new measurements will produce a data base with high statistics and large kinematic coverage for the hadronic invariant mass （W） up to 2.0 CeV in the momentum transfer （Q2） range of 0.3--6.0 GeV2. Preliminary results will be presented and compared with the various model calculations.