Search NASA⌕ Search

SEARCH · Search NASA

Results for “transverse momentum distributions”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Widths of transverse momentum distributions in intermediate-energy heavy-ion collisions

The need to include dynamical collision momentum transfer contributions, arising from interacting nuclear and Coulomb fields, to estimates of fragment momentum distributions is discussed. Methods based upon an optical potential model are presented. Comparisons with recent experimental data of the Siegen group for variances of transverse momentum distributions for gold nuclei at 980 A MeV fragmenting on silver foil and plastic nuclear track detector targets are made. The agreement between theory and experiment is good.

Khan, Ferdous↗
NASA NTRS1985

Transverse momentum distribution of pion deg in the fragmentation region of super high energy interactions

The lateral distribution of gamma-families observed by emulsion chamber is sensitive to test transverse momentum of high energy interaction. But most part gamma-families are succesive interation's results which makes it necessary to analyze the propagation of gamma-ray in atmosphere. A gamma-ray with energy Er and transverse momentum Pt is produced at the altitude h. In the emulsion chamber experiment, Eob is estimated by decascade method. There are 30 gamma-families observed by Ganbala emulsion Chamber. A group of Monte-Carlo simulation gamma-families are used to compare with experimental data with the same treatment. It is found that both distributions are consistent.

Ren, J. R.↗
NASA NTRS1985

The nucleon intensity in the atmosphere and the Pt distribution

The diffusion equation for cosmic ray nucleons in the atmosphere has been solved analytically, taking into account the transverse momentum distribution of nucleons produced in nucleon-air nucleus collisions. The effect of the transverse momentum distribution increases the nucleon intensity at large zenith angles and low energies.

Liland, A.↗
NASA NTRS1992

Production of H-3 at large momentum in alpha-(C-12) collisions at 2A GeV

Calculations of the longitudinal and transverse momentum distributions for H-3 production at large momentum in alpha-(C-12) collisions near 2A GeV are compared to experiment. Triton exchange and final-state interactions are shown to represent large corrections to the impulse approximation for proton knockout. A method for calculating interference effects for inelastic fragmentation is discussed. Good agreement with experiment using a phenomenological overlap function for (H-3)-p is found successful in describing H-3 production in pion-induced reactions. Comparisons to momentum distributions obtained through (p, 2p) and (e, ep) reactions on He-4 are made.

Cucinotta, Francis A.↗
NASA NTRS1985

Nucleon-nucleus interactions from JACEE

Results on hadron-nucleus interactions from the Japanese-American Cooperation Emulsion Experiment experiment are presented. Angular distributions for charged particles, and angular and transverse momentum spectra for photons have been measured for a sample of events with sigma epsilon sub gamma. Results on central rapidity density and transverse energy flow are discussed.

Burnett, T. H.↗
NASA NTRS1989

Nuclear fragmentation energy and momentum transfer distributions in relativistic heavy-ion collisions

An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

Khandelwal, Govind S.↗
NASA NTRS1976

Multiplicity dependence of transverse momentum in hadronic collisions

The process of secondary-particle emission in hadron-hadron collisions is analytically studied using a simple model of hadron structure. The model neglects the 'size' of the hadron constituents, considering a hadron as a continuous distribution of matter according to a step function of radius R. A version of the eikonal approximation is applied to derive the relative probability for interaction and emission of secondaries when the impact parameter b is smaller than 2R. On the basis of these assumptions, and using the uncertainty relation, an empirical parameterization is obtained for the dependence of the transverse momentum of charged secondaries on their multiplicity in the case of high-energy proton-proton collisions. Comparison with experimental data at 28 GeV/c yields agreement to within about 3%. The analysis shows that at a fixed beam momentum, the transverse momentum decreases with increasing multiplicity, and that for a given multiplicity, the transverse momentum exhibits a slow increase with beam momentum.

Saint Amand, J.↗
NASA NTRS1982

Dilution Jet Mixing Program, phase 1

The effect of jet to mainstream density ratio, flow area convergence as encounted in transition sections, and nonuniform mainstream profile upstream of dilution orifices on the mixing of a row of jets with a confined cross flow was quantified. It is found that: (1) jet spreading rate in transverse direction is increased with increasing J, H/D and with decreasing S/D; (2) the density ratio has only a second order effect on the jet mixing characteristics for a constant momentum ratio; (3) the temperature distributions in the jet mixing region are strongly influenced by the undisturbed mainstream profile; (4) flow area convergence enhances mixing in radial and transverse directions. An asymmetric convergent duct with flat wall injection has the same jet mixing characteristics as a symmetric convergent duct. An asymmetric convergent duct with slant wall injection has a faster jet spreading rate in the transverse direction.

Srinivasan, R.↗
NASA NTRS1975

The dynamics of spin stabilized spacecraft with movable appendages, part 1

The motion and stability of spin stabilized spacecraft with movable external appendages are treated both analytically and numerically. The two basic types of appendages considered are: (1) a telescoping type of varying length and (2) a hinged type of fixed length whose orientation with respect to the main part of the spacecraft can vary. Two classes of telescoping appendages are considered: (a) where an end mass is mounted at the end of an (assumed) massless boom; and (b) where the appendage is assumed to consist of a uniformly distributed homogeneous mass throughout its length. For the telescoping system Eulerian equations of motion are developed. During all deployment sequences it is assumed that the transverse component of angular momentum is much smaller than the component along the major spin axis. Closed form analytical solutions for the time response of the transverse components of angular velocities are obtained when the spacecraft hub has a nearly spherical mass distribution.

Bainum, P. M.↗
NASA NTRS1976

Dynamics of spin stabilized spacecraft during deployment of telescoping appendages

The dynamics of a spin stabilized spacecraft with telescoping appendages are treated both analytically and numerically. Two types of telescoping appendages are considered: (a) where an end mass is mounted at the end of an (assumed) massless boom; and (b) where the appendage is assumed to consist of a uniformly distributed homogeneous mass throughout its length. For the telescoping system Eulerian equations of motion are developed. During all deployment sequences it is assumed that the transverse component of angular momentum is much smaller than the component along the major spin axis. Closed form analytical solutions for the time response of the transverse components of angular velocities are obtained when the spacecraft hub has a nearly spherical mass distribution. For the more general case, a series solution is obtained and this solution is limited by its radius of convergence. The comparison of the different approximate analytical methods with numerical integration results are studied and it is observed that the oscillatory nature of the responses of the transverse angular velocity components reduces rapidly with faster extension rates.

Sellappan, R.↗
NASA NTRS1983

Extremely high multiplicities in high-energy nucleus-nucleus collisions

Two unusually-high-multiplicity interactions of high-energy heavy nuclei were observed in a balloon-borne emulsion chamber: an Si(+)AgBr event (4 TeV/nucleon) and a Ca(+)C event (100 TeV/nucleon), with 1015 and 760 charged particles, respectively. The multiplicities and rapidity distributions favor the multichain model but not the wounded-nucleon superposition model. The high average transverse momentum (550-700 MeV/c) and the rapid fluctuations of the events are not readily understood in terms of any superposition models.

Burnett, T. H.↗
NASA NTRS1922

Notes on aerodynamic forces 1 : rectilinear motion

The study of the motion of perfect fluids is of paramount importance for the understanding of the chief phenomena occurring in the air surrounding an aircraft, and for the numerical determination of their effects. The author recently successfully employed some simple methods for the investigation of the flow of a perfect fluid that have never been mentioned in connection with aeronautical problems. These methods appeal particularly to the engineer who is untrained in performing laborious mathematical computations, as they do away with these and allow one to obtain many interesting results by the mere application of some general and well-known principles of mechanics. Discussed here are the kinetic energy of moving fluids, the momentum of a body in a perfect fluid, two dimensional flow, three dimensional flow, and the distribution of the transverse forces of very elongated surfaces of revolution.

Munk, Max M↗
NASA NTRS1983

Large-amplitude hydromagnetic waves in collisionless relativistic plasma - Exact solution for the fast-mode magnetoacoustic wave

An exact nonlinear solution is found to the relativistic kinetic and electrodynamic equations (in their hydromagnetic limit) that describes the large-amplitude fast-mode magnetoacoustic wave propagating normal to the magnetic field in a collisionless, previously uniform plasma. It is pointed out that a wave of this kind will be generated by transverse compression of any collisionless plasma. The solution is in essence independent of the detailed form of the particle momentum distribution functions. The solution is obtained, in part, through the method of characteristics; the wave exhibits the familiar properties of steepening and shock formation. A detailed analysis is given of the ultrarelativistic limit of this wave.

Barnes, A.↗
NASA NTRS1972

Experiments on a turbulent jet in a cross flow.

Results are reported of experiments on turbulent circular jets issuing into a cross flow, both for unheated and heated jets. Longitudinal and transverse distributions of velocity, temperature, and turbulence intensity are presented. The velocity distributions depend mainly on the ratio of jet to cross flow momentum flux. The temperature distributions depend also on the density ratio. The jet structure is dominated by a vortex wake which forms behind the jet, which is evident both from the detail measurements and from smoke photographs of the flow. The experiments also indicate that the components of cross flow normal and parallel to the jet trajectory independently control the entrainment rate.

Kamotani, Y.↗
NASA NTRS1991

Experimental study of cross-stream mixing in a cylindrical duct

An experimental investigation of cross stream injection and mixing was conducted with application to a low NO sub x combustor for the High Speed Civil Transport (HSCT). Mixing in a cylindrical chamber was studied for transverse injection from slanted slot and round orifice injectors. Momentum ratio, density ratio, and number were studied. Quantitative measurement of injectant concentration distributions were obtained by planar digital imaging of the Mie scattered light from an aerosol seed uniformly mixed with the injectant. The unmixedness, defined as the ratio of the r.m.s. concentration fluctuation to mean concentration in a plane perpendicular to the main flow direction, was found to be primarily a function of momentum ratio and injector spacing. An optimum spacing is indicated. Unmixedness is also a function of orifice size, or mass flow ratio, but the mass flow dependence can be accounted for by normalizing the unmixedness with its maximum theoretical value. The data indicate that a density ratio greater than unity retards mixing. It was found that above a certain momentum flux ratio, mixing with slanted slot injectors was better than with round hole injectors.

Vranos, A.↗
NASA NTRS1989

Nuclear collective flow and charged-pion emission in Ne-nucleus collisions at E/A = 800 MeV

Triple-differential cross sections of charged pions were measured for collisions of Ne projectiles at E/A = 800 MeV with NaF, Nb, and Pb targets. The reaction plane was estimated event by event from the light-baryon momentum distribution. For heavy targets, preferential emission of charged pions away from the interaction zone toward the projectile side was observed in the transverse direction. Such a preferential emission, which is not predicted by cascade calculations, may be attributed to a stronger pion absorption by the heavier spectator remnant.

Gosset, J.↗
NASA NTRS1989

Nuclear collective flow and charged-pion emission in Ne-nucleus collisions at E/A = 800 MeV

Triple-differential cross sections of charged pions were measured for collisions of Ne projectiles at E/A = 800 MeV with NaF, Nb, and Pb targets. The reaction plane was estimated event by event from the light-baryon momentum distribution. For heavy targets, preferential emission of charged pions away from the interaction zone towards the projectile side was observed in the transverse direction. Such a preferential emission, which is not predicted by cascade calculations, may be attributed to a stronger pion absorption by the heavier spectator remnant.

NASA Discipline Number 04-10↗
NASA NTRS1985

QCD-motivated description of very high energy particle interactions

Cross sections for the production of secondaries with large transverse momentum can become comparable to the total cross section in the TeV energy range. It is argued that the onset of this effect is observed at sub TeV energies via an increase of the rapidity distribution near y = 0, an increase of p sub T with energy and, most directly, via a correlation between p sub T and multiplicity. If indeed scaling violations are associated with the hard scattering of partons, then scaling violations are largely confined to the central region and have little effect on cosmic ray data which are sensitive to the forward fragmentation region.

Gaisser, T. K.↗