Latent Tracks in Ion-Irradiated LiTaO3 Crystals: Damage Morphology Characterization and Thermal Spike Analysis

Systematic research on the response of crystal materials to the deposition of irradiation energy to electrons and atomic nuclei has attracted considerable attention since it is fundamental to understanding the behavior of various materials in natural and manmade radiation environments. This work examines and compares track formation in LiTaO3 induced by separate and combined effects of electronic excitation and nuclear collision. Under 0.71–6.17 MeV/u ion irradiation with electronic energy loss ranging from 6.0 to 13.8 keV/nm, the track damage morphologies evolve from discontinuous to continuous cylindrical zone. Based on the irradiation energy deposited via electronic energy loss, the subsequently induced energy exchange and temperature evolution processes in electron and lattice subsystems are calculated through the inelastic thermal spike model, demonstrating the formation of track damage and relevant thresholds of lattice energy and temperature. Combined with a disorder accumulation model, the damage accumulation in LiTaO3 produced by nuclear energy loss is also experimentally determined. The damage characterizations and inelastic thermal spike calculations further demonstrate that compared to damage-free LiTaO3, nuclear-collision-damaged LiTaO3 presents a more intense thermal spike response to electronic energy loss owing to the decrease in thermal conductivity and increase in electron–phonon coupling, which further enhance track damage.

Secondary Drell–Yan dileptons in heavy-ion reactions

We investigate the contribution of partonic interactions between incident nucleons and produced mesons to the dilepton continuum in heavy-ion reactions. A schematic model is employed in order to calculate the resulting Drell–Yan yield as a function of collision energy and for different scenarios concerning the formation of hadrons. The secondary Drell–Yan process is found to be significant for invariant masses [Formula: see text][Formula: see text]GeV in central [Formula: see text] collisions around [Formula: see text][Formula: see text]GeV, but less so at much lower or much higher energies. Secondary Drell–Yan dileptons should be observable in experiments due to their distinct rapidity dependence as a characteristic deviation from the well-known (primary) Drell–Yan contribution due to [Formula: see text] interactions. The predicted strong dependence of the secondary Drell–Yan contribution on the nuclear collision energy can be used to experimentally probe the effective hadronic formation time of secondaries.

Properties of Non-Instant and Nonlocal Corrections

The derived nonlocal and non-instant shifts are discussed with respect to various symmetries and gauges. The classical counterparts are derived and found in agreement with the expected phenomenological ones from chapter 3. The explicit forms of the hard-sphere like offsets and the delay time in terms of the scattering phase shifts are calculated and discussed on the example of nuclear collision. The numerical results reveal an interesting inside into the microscopic correlations developed in dependence on the scattering angle and scattering energy. The just-accomplished derivation of the nonlocal scattering integrals is far from being intuitive. We have reached our task, the kinetic equation, being guided by nothing but systematic implementation of the quasiclassical approximation and the limit of small scattering rates.

Fractal study of pion void probability distribution in ultrarelativistic nuclear collision and its target dependence

There are numerous existing works on investigating the dynamics of particle production process in ultrarelativistic nuclear collision. In the past, fluctuation of spatial pattern has been analyzed in terms of the scaling behavior of voids. But analysis of the scaling behavior of the void in fractal scenario has not been explored yet. In this work, we have analyzed the fractality of void probability distribution with a completely different and rigorous method called visibility graph analysis, analyzing the void-data produced out of fluctuation of pions in [Formula: see text]S–AgBr interaction at 200 GeV in pseudo-rapidity [Formula: see text] and azimuthal angle [Formula: see text] space. The power of scale-freeness of visibility graph denoted by PSVG is a measure of fractality, which can be used as a quantitative parameter for the assessment of the state of chaotic system. As the behavior of particle production process depends on the target excitation, we can dwell down the void probability distribution in the event-wise fluctuation resulted out of the high energy interaction for different degree of target excitation, with respect to the fractal scenario and analyze the scaling behavior of the voids. From the analysis of the PSVG parameter, we have observed that scaling behavior of void probability distribution in multipion production changes with increasing target excitation. Since visibility graph method is a classic method of complex network analysis, has been applied over fractional Brownian motion (fBm) and fractional Gaussian noises (fGn) to measure the fractality and long-range dependence of a time series successfully, we can quantitatively confirm that fractal behavior of the void probability distribution in particle production process depends on the target excitation.

Study of Void Probability Scaling of Singly Charged Particles Produced in Ultrarelativistic Nuclear Collision in Fractal Scenario

We study the fractality of void probability distribution measured inS32-Ag/Br interaction at an incident energy of 200 GeV per nucleon. A radically different and rigorous method calledVisibility Graphanalysis is used. This method is shown to reveal a strong scaling character of void probability distribution in all pseudorapidity regions. The scaling exponent, called the Power of the Scale-Freeness in Visibility Graph (PSVG), a quantitative parameter related to Hurst exponent, is strongly found to be dependent on the rapidity window size.