Degree Of Stopping Research Articles

Influence of Momentum-Dependent Interactions on the Nuclear Stopping in Symmetric Heavy-Ion Collisions

The role of momentum-dependent interactions (MDI) in the nuclear stopping at intermediate energies using an isospin-dependent quantum molecular dynamics model is studied. The calculations are performed for incident energies between 50 and 1000 MeV/nucleon. Our findings show that the nuclear stopping is sensitive to the impact parameter, incident energy, and the mass of the colliding system. The degree of stopping is suppressed by the inclusion of MDI, whereas the particle production is not affected by MDI.

In-mediumNNcross sections determined from the nuclear stopping and collective flow in heavy-ion collisions at intermediate energies

In-medium nucleon-nucleon scattering cross sections are explored by comparing results of quantum molecular dynamics simulations to data on stopping and on elliptic and directed flow in intermediate-energy heavy-ion collisions. The comparison points to in-medium cross sections which are suppressed at low energies but not at higher energies. Positive correlations are found between the degree of stopping and the magnitudes of elliptic and directed flows.

Nuclear stopping from 0.09A to 1.93A GeV and its correlation to flow.

We present a complete systematics (excitation functions and system-size dependences) of global stopping and side flow for heavy ion reactions in the energy range between 0.09A and 1.93A GeV. For the heaviest system, Au+Au, we observe a plateau of maximal stopping extending from about 0.2A to 0.8A GeV with a fast drop on both sides. The degree of stopping, which is shown to remain significantly below the expectations of a full stopping scenario, is found to be highly correlated to the amount of side flow.

Constraints on the equation of state of nuclear matter from nucleus-nucleus collisions

We present the current status of extracting information on hot and compressed nuclear matter from nucleus-nucleus collisions with particular emphasis on the intermediate energy range, (0.1–2)A GeV. Our keywords are collective flow, subthreshold particle production, momentum dependence, degree of stopping, scaling and isospin.

Constraints on the equation of state of nuclear matter from nucleus-nucleus collisions

We present the current status of extracting information on hot and compressed nuclear matter from nucleus-nucleus collisions with particular emphasis on the intermediate energy range, (0.1–2)A GeV. Our keywords are collective flow, subthreshold particle production, momentum dependence, degree of stopping, scaling and isospin.

Bremsstrahlung from a microscopic model of relativistic heavy ion collisions

We compute bremsstrahlung arising from the acceleration of individual charged baryons and mesons during the time evolution of high-energy $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at the Relativistic Heavy Ion Collider using a microscopic transport model. We elucidate the connection between bremsstrahlung and charge stopping by colliding artificial pure proton on pure neutron nuclei. From the intensity of low energy bremsstrahlung, the time scale and the degree of stopping could be accurately extracted without measuring any hadronic observables.

Stopping: from Peripheral to Central Nuclear Collisions at the SPS

New results on baryon stopping at the CERN SPS, measured by the inclusive net proton (p- p ) rapidity distribution, are presented for centrality selected Pb+Pb and p+Pb, as well as minimum bias p+p collisions. A smooth evolution in the degree of stopping is observed when going from small to large systems, with the greatest stopping in the most central p+Pb collisions. On the other hand, longitudinal distributions of produced particles vary little with the size of the system, and the total yield of pions scales approximately with the number of participating nucleons.

Stopping: from peripheral to central nuclear collisions at the SPS

New results on baryon stopping at the CERN SPS, measured by the inclusive net proton (p- p ) rapidity distribution, are presented for centrality selected Pb+Pb and p+Pb, as well as minimum bias p+p collisions. A smooth evolution in the degree of stopping is observed when going from small to large systems, with the greatest stopping in the most central p+Pb collisions. On the other hand, longitudinal distributions of produced particles vary little with the size of the system, and the total yield of pions scales approximately with the number of participating nucleons.

Multiple-collision model for high-energy nucleus-nucleus collisions.

We use a Glauber multiple-collision model to examine the dynamics of nucleus-nucleus collisions. The model introduces a stopping law which describes how a baryon loses energy in a basic baryon-baryon collision and a particle production law which relates the distribution of produced particles to the baryon momentum loss. The model gives results which compare well with the recent WA80 experimental data of $^{16}\mathrm{O}$ on various targets at 60 and 200 GeV per projectile nucleon and reveals a high degree of stopping in these high-energy nuclear collisions.

STUDY OF INELASTIC α-EMULSION INTERACTIONS AT 12A GeV/c

Various multiplicities and their dependence on the mass number of the target, multiplicity correlations and angular distributions of black, grey, heavy and shower particles are studied and are compared with α-Em (4.2 A GeV /c) and p-Em (6.2–50 GeV /c) interactions. Slow particles seem to cascade unlike the produced shower particles. We also observe a different degree of stopping for different thicknesses of the nuclear matter traversed by the projectile. In general, our results are similar to those for hadron-nucleus collisions.

Investigation of frequency-selective losses of a reflecting grating in a laser resonator

An analysis is made of the selective properties of a resonator formed by a reflecting diffraction grating and a mirror. The frequency-selective loss function (FSLF) of this resonator is determined. If the grating is considered to be an equivalent plane mirror with angular dispersion, the problem of losses due to misalignment of the grating is reduced to the problem of losses for a tilted-mirror resonator. An integral equation derived for this case was solved by computer. By using Gaussian quadrature formulas for numerical integration and an efficient algorithm, all the highest-Q oscillation modes can be determined directly with a low usage of computer time. The grating FSLF is obtained and it is found to be determined by the dependence of the increase in the insertion losses on the angular misalignment of the grating. Initially the dependence is parabolic and then increases linearly. Experimental measurements were made of the FSLF for a CO2 laser with 100 and 150 lines/mm intracavity gratings for various values of the confocal parameter 1–0.56 and the degree of stopping down 0.55–0.35. The results agree with the calculations.

Reproducibility of the frequency of a quantum reference source stabilized by theEcomponent of the methane molecule

An experimental study was made of the reproducibility of the frequency of an He–Ne laser stabilized by the E component of the ν3[P(7)] transition in the methane molecule. The frequency of the output radiation was influenced by the principal parameters and the operating conditions of the laser, including its output power, methane pressure, detuning of the gain line relative to the absorption of methane, and amplitude of the frequency deviation of the laser radiation. It was found that the laser frequency depended strongly on the degree of stopping down of the laser beam by the amplifying tube. The reproducibility of the laser radiation frequency achieved in these experiments was 5×10−13. An estimate was obtained of the maximum precision of the frequency reproducibility of an unperturbed transition in this type of laser.