Dynamical Study on Fusion Barrier in the Synthesis of Superheavy Elements

Based on the improved isospin-dependent quantum molecular dynamics model, the fusion barrier in the synthesis of superheavy elements is studied dynamically. Deformation effect and nucleon transfer in neck region are also investigated systematically, which can lower the dynamical barrier since the neck formation. It is shown that the neck radius is dependent on the incident energy and collision orientation. For the static barrier, the model almost gives the same results with the proximity potential.     

Energy dependence of direct effects in the6Li +6Li → 3α reaction around the Coulomb Barrier

The⁶Li +⁶Li → 3α reaction has been studied from 2.4 to 6.7 MeV incident energy in a kinematically complete experiment. Quasi-free effects with an α-particle spectator in the target, in the projectile and in the CM-system were investigated. Momentum distributions and angular correlations were interpreted by using PWIA and DWBA.     

Conversion Electron Mössbauer Study of Mixing Induced by Swift Heavy Ions at the Fe/Si Interface

Conversion Electron Mössbauer Spectroscopy (CEMS) was employed in order to study the mixing induced by swift Au and Ag ions at the Fe/Si interface in the Fe/Fe⁵⁷/Si system. An increase in the amount of mixing with ion fluence and electronic energy loss (S _e) has been observed. Atomic Force Microscopy (AFM) results provided indirect evidence to support the above observations.     

Theoretical Analysis of Ionic Autoionization Spectra of Lanthanum in the Energy Region of 90650—915—00cm^—1

Eigenquantum defects μα and transformation matrix Uiα of La are calculated from the first principles byrelativistic multichannel theory, and dipole matrix elements Dα are obtained by fitting the experimental spectra.With these parameters, ionic autoionization spectra of lanthanum via an intermediatestate (Xe)5d6d^-1 P1 of La . in the energy region of 90650-91500 cm^-1 are calculated within the framework of multichannel auantum defecttheory. Our calculated spectra are in general agreement with the experimental data.     

Comparison of Methods for Eliminating the Bohr–Weisskopf Effect in Atomic Spectra of $${}^{{209}}$$ Bi Heavy Ions

Physics of Atomic Nuclei - The methods of the ratio and specific differences of values of hyperfine splitting in different shells for eliminating the Bohr–Weisskopf effect in...     

Study of Events with Two Leptons in the Final State to Investigate Properties of the Standard Model Higgs Boson and Search for a Heavy Higgs Boson in the h/H → WW(*) → ��ν��ν Decay in pp Collisions at 13 TeV with the ATLAS Detector at the LHC

Physics of Atomic Nuclei - The authors, members of the ATLAS Higgs boson working group (HWW), studied events with two leptons in the...     

Multi-Component Study of Extensive Air Showers at the Tien Shan Mountain Station of LPI and Peculiarities of the Particles Flux Behavior in the Central Region of the (1–100) PeV EAS

Physics of Atomic Nuclei - New multipurpose experimental complex of the Tien Shan mountain cosmic ray station of LPI incorporates a set of detector subsystems for simultaneous investigation of the...     

Z-Boson Control Region and Search for a Heavy Higgs Boson in H → WW → ℓvℓv Decay Channel in Proton—Proton Collisions at 13 TeV with the ATLAS Experiment at LHC

The control region of Z-bosons produced in pp collisions at 13 TeV with the ATLAS detector at LHC is studied. This investigation, carried out by the authors as members of the HWW working group, is aimed at checking the algorithms applied for reconstructing the H → WW → ℓvℓv decays of a hypothetical heavy Higgs boson (HHB) sought by the LHC experiments. The analysis relies on the complete sample of proton-proton collisions recorded by ATLAS in 2015–2016 and pays special attention to variations of hadron-jet kinematic characteristics with the collider luminosity. A dedicated software package within the HWW information medium is developed and implemented for plotting kinematic distributions for correlated jets as functions of the number of collisions per beam crossing and of the number of primary vertices per event. On the whole, mean values of kinematic characteristics are found to follow linear dependences on the luminosity which are adequately reproduced by the simulation. Since the hadron-jet selection criteria are similar for the hypothetical HHB and for the Standard Model Higgs boson (SM H) already discovered at the LHC, the reported analysis is also relevant for experimental studies of the SM H properties. In this paper, we also report on initial results of the new search for the HHB at 13 TeV based on ameliorated event reconstruction algorithms and updated software. No significant differences between the results of the new and previous analyses are revealed.

     

Determination of the Potential Barrier at the Metal／Oxide Interface in a Specular Spin Valve Structure with Nano—oxide Layers Using Electron Holography

The local potential distribution in a specular spin valve structure with nano-oxide layers has been mapped by using off-axis electron holography in a field emission gun transmission electron microscope.A potential jump of 3-4 V across the metal/oxide interface was detected for the first time.The presence of the potential barrier confirms the formation of the metal/insulator/metal structure,which contributes to the increasing mean free path of spin-polarized elecrons via the specular reflection of spin-polarized electrons at the metal/oxide interface.It leads to nearly double enhancement of the magnetoresistance ratio from 8% to 15%.     

An Investigation of Signal Kinematical Region to Study Standard Model Higgs Boson Properties in the H → WW* → ℓvℓv Decay Channel in the ATLAS Experiment at the Large Hadron Collider at 13 TeV

A signal kinematical region is analyzed by the Higgs Boson Working Group (HWW) within the framework of a study of the Standard Model Higgs boson properties in the H → WW* → evεv decay channel in the ATLAS experiment on the Large Hadron Collider (LHC). The analysis is based on the full statistics of proton-proton collision data during exposures in 2015–2016 at the center-of-mass energy of 13 TeV. As compared to our previous analysis, the reconstruction software is updated and the simulation accuracy of backgrounds is improved. Events taken at low and high LHC luminosity are studied separately. In addition, the kinematics at the later stages of event selection is investigated in detail and systematic uncertainties are fully estimated. It is shown that the Monte Carlo modeling satisfactorily describes the experimental data at different selection stages. Kinematic distributions for hadron jets are studied also in the Z-boson control region, where the acquired data reach the order of ten million events. As compared to the previous investigation, the modeling accuracy of Z and background processes is noticeably improved, and events at low and high LHC luminosities are studied separately. Furthermore, all systematic uncertainties related to jets are estimated as well. As a whole, good agreement between experimental results and Monte Carlo simulation data is observed. No problems that would be caused by high luminosity are observed.

     

Study of Events with an Electron,Muon, and Two Hadron Jets in the Final State with an Integrated Luminosity of a 139 fb–1 in pp Collisions at $$\sqrt s $$ = 13 TeV with the ATLAS Detector at the LHC

Physics of Atomic Nuclei - To investigate the Higgs boson properties in the h → WW* → еνμν decay channel, events with an electron, muon, and two hadron jets in the...