WorldWideScience

Sample records for halo particle production

  1. Simulation of halo particles with Simpsons

    International Nuclear Information System (INIS)

    Machida, Shinji

    2003-01-01

    Recent code improvements and some simulation results of halo particles with Simpsons will be presented. We tried to identify resonance behavior of halo particles by looking at tune evolution of individual macro particle

  2. Simulation of halo particles with Simpsons

    Science.gov (United States)

    Machida, Shinji

    2003-12-01

    Recent code improvements and some simulation results of halo particles with Simpsons will be presented. We tried to identify resonance behavior of halo particles by looking at tune evolution of individual macro particle.

  3. Unbound particles in dark matter halos

    Energy Technology Data Exchange (ETDEWEB)

    Behroozi, Peter S.; Loeb, Abraham; Wechsler, Risa H.

    2013-06-13

    We investigate unbound dark matter particles in halos by tracing particle trajectories in a simulation run to the far future (a = 100). We find that the traditional sum of kinetic and potential energies is a very poor predictor of which dark matter particles will eventually become unbound from halos. We also study the mass fraction of unbound particles, which increases strongly towards the edges of halos, and decreases significantly at higher redshifts. We discuss implications for dark matter detection experiments, precision calibrations of the halo mass function, the use of baryon fractions to constrain dark energy, and searches for intergalactic supernovae.

  4. Studies of emittance growth and halo particle production in intense charged particle beams using the Paul Trap Simulator Experiment

    International Nuclear Information System (INIS)

    Gilson, Erik P.; Davidson, Ronald C.; Dorf, Mikhail; Efthimion, Philip C.; Majeski, Richard; Chung, Moses; Gutierrez, Michael S.; Kabcenell, Aaron N.

    2010-01-01

    The Paul Trap Simulator Experiment (PTSX) is a compact laboratory experiment that places the physicist in the frame-of-reference of a long, charged-particle bunch coasting through a kilometers-long magnetic alternating-gradient (AG) transport system. The transverse dynamics of particles in both systems are described by the same set of equations, including nonlinear space-charge effects. The time-dependent voltages applied to the PTSX quadrupole electrodes in the laboratory frame are equivalent to the spatially periodic magnetic fields applied in the AG system. The transverse emittance of the charge bunch, which is a measure of the area in the transverse phase space that the beam distribution occupies, is an important metric of beam quality. Maintaining low emittance is an important goal when defining AG system tolerances and when designing AG systems to perform beam manipulations such as transverse beam compression. Results are reviewed from experiments in which white noise and colored noise of various amplitudes and durations have been applied to the PTSX electrodes. This noise is observed to drive continuous emittance growth and increase in root-mean-square beam radius over hundreds of lattice periods. Additional results are reviewed from experiments that determine the conditions necessary to adiabatically reduce the charge bunch's transverse size and simultaneously maintain high beam quality. During adiabatic transitions, there is no change in the transverse emittance. The transverse compression can be achieved either by a gradual change in the PTSX voltage waveform amplitude or frequency. Results are presented from experiments in which low emittance is achieved by using focusing-off-defocusing-off waveforms.

  5. New Spectral Method for Halo Particle Definition in Intense Mis-matched Beams

    Energy Technology Data Exchange (ETDEWEB)

    Dorf, Mikhail A.; Davidson, Ronald C.; Startsev, Edward A.

    2011-04-27

    An advanced spectral analysis of a mis-matched charged particle beam propagating through a periodic focusing transport lattice is utilized in particle-in-cell (PIC) simulations. It is found that the betatron frequency distribution function of a mismatched space-charge-dominated beam has a bump-on-tail structure attributed to the beam halo particles. Based on this observation, a new spectral method for halo particle definition is proposed that provides the opportunity to carry out a quantitative analysis of halo particle production by a beam mismatch. In addition, it is shown that the spectral analysis of the mismatch relaxation process provides important insights into the emittance growth attributed to the halo formation and the core relaxation processes. Finally, the spectral method is applied to the problem of space-charge transport limits.

  6. Giant Radio Halos in Galaxy Clusters as Probes of Particle ...

    Indian Academy of Sciences (India)

    scenario still remain poorly understood. ... to test models with future observations. ... A popular scenario for the origin of radio halos assumes that relativis- ..... based on particle acceleration by merger-driven turbulence in galaxy clusters shows.

  7. Conditions for minimization of halo particle production during transverse compression of intense ion charge bunches in the Paul Trap Simulator Experiment (PTSX)

    International Nuclear Information System (INIS)

    Gilson, Erik P.; Chung, Moses; Davidson, Ronald C.; Dorf, Mikhail; Efthimion, Philip C.; Grote, David P.; Majeski, Richard; Startsev, Edward A.

    2007-01-01

    The Paul Trap Simulator Experiment (PTSX) is a compact laboratory Paul trap that simulates propagation of a long, thin charged-particle bunch coasting through a multi-kilometer-long magnetic alternating-gradient (AG) transport system by putting the physicist in the frame-of-reference of the beam. The transverse dynamics of particles in both systems are described by the same sets of equations-including all nonlinear space-charge effects. The time-dependent quadrupolar voltages applied to the PTSX confinement electrodes correspond to the axially dependent magnetic fields applied in the AG system. This paper presents the results of experiments in which the amplitude of the applied confining voltage is changed over the course of the experiment in order to transversely compress a beam with an initial depressed tune ν/ν 0 ∼0.9. Both instantaneous and smooth changes are considered. Particular emphasis is placed on determining the conditions that minimize the emittance growth and, generally, the number of particles that are found at large radius (so-called halo particles) after the beam compression. The experimental data are also compared with the results of particle-in-cell (PIC) simulations performed with the WARP code

  8. Giant Radio Halos in Galaxy Clusters as Probes of Particle ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Giant radio halos in galaxy clusters probe mechanisms of particle acceleration connected with cluster merger events. Shocks and turbulence are driven in the inter-galactic medium (IGM) during clusters mergers and may have a deep impact on the non-thermal properties of galaxy clusters. Models of ...

  9. Halo structure of strange particles in nuclei

    International Nuclear Information System (INIS)

    Akaishi, Yoshinori; Yamazaki, Toshimitsu.

    1997-01-01

    Some characteristic behaviors of hyperons in nuclei which have recently been revealed experimentally and theoretically are discussed with the emphasis on the repulsive part of the hyperon-nucleus interaction. The observed Σ 4 He nucleus is a bound state with J π = 0 + and T ≅ 1/2. Its nucleus-Σ potential derived from a realistic ΣN interaction is characterized by inner repulsion and a strong Lane term, which play important roles in forming the Σ-hypernuclear bound state. In 208 Pb a typical Coulomb-assisted bound state is expected, where Σ is trapped in the surface region by the nucleus-Σ potential with the aid of Coulomb and centrifugal interactions. In the double-strangeness (S=-2) sector, there is a possibility that the lightest double-Λ hypernucleus ΛΛ 4 H is abundantly populated by stopping Ξ - on 4 He. Its formation branching amounts to about 15%. A stopped Ξ - on 9 Be will also produce efficiently a variety of double-Λ hyperfragments. Discrete spectra of weak-decay pions from the fragments will provide a means of mass spectroscopy of double-Λ hypernuclei. In the S=-2 five-body system an excited state Ξ 5 H is predicted to appear with 'strangeness halo' and the ground state ΛΛ 5 H with almost pure ΛΛ component. (author)

  10. Halo's production in vitro on brachytherapy experiments

    International Nuclear Information System (INIS)

    Cuperschmid, Ethel M.; Sarmento, Eduardo V.; Campos, Tarcisio P.R.

    2011-01-01

    Since earlier of 1960, one of the most significant contributions of radiation biology has been the theory of cell killing as a function of increasing doses of a cytotoxic agent, as well as the demonstration of repair of sublethal or potentially lethal damage after irradiation. The impact of cellular and molecular radiobiology, by exploitation of cellular mechanisms related to apoptosis, may be the cell killing with irradiation by including changes other than unrepaired DNA damage. Based on the understanding of the tumor microenvironment and how growth factors and proteins produced by irradiated cells may alter cellular processes, improved combined-modality strategies may emerge. This effect was show since 1960's, but here we propose to demonstrate this phenomenon in Brachytherapy. The present goal is to verify the macroscopic response through the production and analysis of clonogenic control based on halos generation by radioactive seeds of Ho-165 and Sm-153, aiming to study the effect of this type of irradiation. Confluent cell culture flasks with HeLa cell line were subjected to radiation in a period up to five half-lives of radionuclide, respectively. Devices were introduced which set the polymer-ceramic Ho-165 and Sm-153 seeds in the vials. After a period of exposure, the flasks were stained with violet Gensiana. The results showed the formation of halos control of confluent cancer cells. This paper will describe these experiments in the current stage of the research and report the implications of this new way of therapy for cancer treatment. (author)

  11. The Splashback Radius of Halos from Particle Dynamics. I. The SPARTA Algorithm

    Science.gov (United States)

    Diemer, Benedikt

    2017-07-01

    Motivated by the recent proposal of the splashback radius as a physical boundary of dark-matter halos, we present a parallel computer code for Subhalo and PARticle Trajectory Analysis (SPARTA). The code analyzes the orbits of all simulation particles in all host halos, billions of orbits in the case of typical cosmological N-body simulations. Within this general framework, we develop an algorithm that accurately extracts the location of the first apocenter of particles after infall into a halo, or splashback. We define the splashback radius of a halo as the smoothed average of the apocenter radii of individual particles. This definition allows us to reliably measure the splashback radii of 95% of host halos above a resolution limit of 1000 particles. We show that, on average, the splashback radius and mass are converged to better than 5% accuracy with respect to mass resolution, snapshot spacing, and all free parameters of the method.

  12. Test of a Diamond Detector Using Unbunched Beam Halo Particles

    CERN Document Server

    Dehning, B; Pernegger, H; Dobos, D; Frais-Kolbl, H; Griesmayer, E

    2010-01-01

    A pCVD diamond detector has been evaluated as a beam loss monitor for future applications in the LHC accelerator. The test monitor was mounted in the SPS BA5 downstream of a LHC collimator during the LHC beam set-up. CVD diamond particle detectors are already in use in the CERN experiments ATLAS, CMS, LHCb and Alice. This is a proven technology with high radiation tolerance and very fast signal read-out. It can be used for single-particle detection, as well as for measuring particle cascades, for timing measurements on the nanosecond scale and for beam protection systems. Despite the read-out being made through 250 m of CK50 cable, the tests have shown a very good signal-to-noise ratio of 6.8, an excellent double-pulse resolution of less than 5 ns and a high dynamic range of 1:350 MIP particles. The efficiency of particle detection is practically 100% for charged particles.

  13. Frozen Hydrocarbon Particles of Cometary Halos as Carriers of ...

    Indian Academy of Sciences (India)

    coma temperature and pressure, bombardment with charged particles, or collisions with gaseous neutrals of cometary atmosphere. The width of each FHP luminescence spectral line seems to depend on the heliocentric distance, since the cometary sub- stance temperature changes with the distance from the sun. Lines of ...

  14. Partial coherence in the core/halo picture of Bose-Einstein n-particle correlations

    OpenAIRE

    Csorgo, T.; Lorstad, B.; Schmidt-Sorensen, J.; Ster, A.

    1998-01-01

    We study the influence of a possible coherent component in the boson source on the two-, three- and $n$-particle correlation functions in a generalized core/halo type of boson-emitting source. In particular, a simple formula is presented for the strengh of the $n$-particle correlation functions for such systems. Graph rules are obtained to evaluate the correlation functions of arbitrary high order. The importance of experimental determination of the 4-th and 5-th order Bose-Einstein correlati...

  15. Dynamics of particles around a pseudo-Newtonian Kerr black hole with halos

    International Nuclear Information System (INIS)

    Wang Ying; Wu Xin

    2012-01-01

    The regular and chaotic dynamics of test particles in a superposed field between a pseudo-Newtonian Kerr black hole and quadrupolar halos is detailed. In particular, the dependence of dynamics on the quadrupolar parameter of the halos and the spin angular momentum of the rotating black hole is studied. It is found that the small quadrupolar moment, in contrast with the spin angular momentum, does not have a great effect on the stability and radii of the innermost stable circular orbits of these test particles. In addition, chaos mainly occurs for small absolute values of the rotating parameters, and does not exist for the maximum counter-rotating case under some certain initial conditions and parameters. This means that the rotating parameters of the black hole weaken the chaotic properties. It is also found that the counter-rotating system is more unstable than the co-rotating one. Furthermore, chaos is absent for small absolute values of the quadrupoles, and the onset of chaos is easier for the prolate halos than for the oblate ones. (general)

  16. Stochastic-hydrodynamic model of halo formation in charged particle beams

    Directory of Open Access Journals (Sweden)

    Nicola Cufaro Petroni

    2003-03-01

    Full Text Available The formation of the beam halo in charged particle accelerators is studied in the framework of a stochastic-hydrodynamic model for the collective motion of the particle beam. In such a stochastic-hydrodynamic theory the density and the phase of the charged beam obey a set of coupled nonlinear hydrodynamic equations with explicit time-reversal invariance. This leads to a linearized theory that describes the collective dynamics of the beam in terms of a classical Schrödinger equation. Taking into account space-charge effects, we derive a set of coupled nonlinear hydrodynamic equations. These equations define a collective dynamics of self-interacting systems much in the same spirit as in the Gross-Pitaevskii and Landau-Ginzburg theories of the collective dynamics for interacting quantum many-body systems. Self-consistent solutions of the dynamical equations lead to quasistationary beam configurations with enhanced transverse dispersion and transverse emittance growth. In the limit of a frozen space-charge core it is then possible to determine and study the properties of stationary, stable core-plus-halo beam distributions. In this scheme the possible reproduction of the halo after its elimination is a consequence of the stationarity of the transverse distribution which plays the role of an attractor for every other distribution.

  17. Meniscus and beam halo formation in a tandem-type negative ion source with surface production

    International Nuclear Information System (INIS)

    Miyamoto, K.; Okuda, S.; Hatayama, A.

    2012-01-01

    A meniscus of plasma-beam boundary in H - ion sources largely affects the extracted H - ion beam optics. Although it is hypothesized that the shape of the meniscus is one of the main reasons for the beam halo observed in experiments, a physical mechanism of the beam halo formation is not yet fully understood. In this letter, it is first shown by the 2D particle in cell simulation that the H - ions extracted from the periphery of the meniscus cause a beam halo since the surface produced H - ions penetrate into the bulk plasma, and, thus, the resultant meniscus has a relatively large curvature.

  18. PHIPS-HALO: the airborne particle habit imaging and polar scattering probe - Part 2: Characterization and first results

    Science.gov (United States)

    Schnaiter, Martin; Järvinen, Emma; Abdelmonem, Ahmed; Leisner, Thomas

    2018-01-01

    The novel aircraft optical cloud probe PHIPS-HALO has been developed to establish clarity regarding the fundamental link between the microphysical properties of single atmospheric ice particles and their appropriated angular light scattering function. After final improvements were implemented in the polar nephelometer part and the acquisition software of PHIPS-HALO, the instrument was comprehensively characterized in the laboratory and was deployed in two aircraft missions targeting cirrus and Arctic mixed-phase clouds. This work demonstrates the proper function of the instrument under aircraft conditions and highlights the uniqueness, quality, and limitations of the data that can be expected from PHIPS-HALO in cloud-related aircraft missions.

  19. Accurate halo-galaxy mocks from automatic bias estimation and particle mesh gravity solvers

    Science.gov (United States)

    Vakili, Mohammadjavad; Kitaura, Francisco-Shu; Feng, Yu; Yepes, Gustavo; Zhao, Cheng; Chuang, Chia-Hsun; Hahn, ChangHoon

    2017-12-01

    Reliable extraction of cosmological information from clustering measurements of galaxy surveys requires estimation of the error covariance matrices of observables. The accuracy of covariance matrices is limited by our ability to generate sufficiently large number of independent mock catalogues that can describe the physics of galaxy clustering across a wide range of scales. Furthermore, galaxy mock catalogues are required to study systematics in galaxy surveys and to test analysis tools. In this investigation, we present a fast and accurate approach for generation of mock catalogues for the upcoming galaxy surveys. Our method relies on low-resolution approximate gravity solvers to simulate the large-scale dark matter field, which we then populate with haloes according to a flexible non-linear and stochastic bias model. In particular, we extend the PATCHY code with an efficient particle mesh algorithm to simulate the dark matter field (the FASTPM code), and with a robust MCMC method relying on the EMCEE code for constraining the parameters of the bias model. Using the haloes in the BigMultiDark high-resolution N-body simulation as a reference catalogue, we demonstrate that our technique can model the bivariate probability distribution function (counts-in-cells), power spectrum and bispectrum of haloes in the reference catalogue. Specifically, we show that the new ingredients permit us to reach percentage accuracy in the power spectrum up to k ∼ 0.4 h Mpc-1 (within 5 per cent up to k ∼ 0.6 h Mpc-1) with accurate bispectra improving previous results based on Lagrangian perturbation theory.

  20. Beam halo studies using a three-dimensional particle-core model

    Directory of Open Access Journals (Sweden)

    Ji Qiang

    2000-06-01

    Full Text Available In this paper we present a study of beam halo based on a three-dimensional particle-core model of an ellipsoidal bunched beam in a constant focusing channel including the effects of nonlinear rf focusing. For an initially mismatched beam, three linear envelope modes—a high frequency mode, a low frequency mode, and a quadrupole mode—are identified for an azimuthally symmetric bunched beam. The high frequency mode has three components all in phase; the low frequency mode has the transverse components in phase and the longitudinal component 180° out of phase; the quadrupole mode has no longitudinal component, and the two transverse components in the mode are 180° out of phase. We also study the case of an ellipsoidal bunched beam without azimuthal symmetry and find that the high frequency mode and the low frequency mode are still present but the quadrupole mode is replaced by a new mode with transverse components 180° out of phase and a nonzero longitudinal component. Previous studies, which generally addressed the situation where the longitudinal-to-transverse focusing strength is roughly 0.6 or less, conclude that the oscillation of the high frequency mode is predominantly transverse, and that of the low frequency mode is predominantly longitudinal. In this paper we present a systematic study of the features of the modes as a function of the longitudinal-to-transverse focusing strength ratio. We find that, when the ratio is greater than unity, the high frequency mode may contain a significant longitudinal component. Thus, excitation of the high frequency mode in this situation can be responsible for the formation of longitudinal beam halo. Furthermore, while previous studies have observed halo amplitudes roughly 2–3 times the matched beam edge, for the present parameters we observe much larger amplitudes (5 times or more. This is due to the fact that the longitudinal-to-transverse focusing ratio used here is greater than that of previous

  1. Comparing semi-analytic particle tagging and hydrodynamical simulations of the Milky Way's stellar halo

    Science.gov (United States)

    Cooper, Andrew P.; Cole, Shaun; Frenk, Carlos S.; Le Bret, Theo; Pontzen, Andrew

    2017-08-01

    Particle tagging is an efficient, but approximate, technique for using cosmological N-body simulations to model the phase-space evolution of the stellar populations predicted, for example, by a semi-analytic model of galaxy formation. We test the technique developed by Cooper et al. (which we call stings here) by comparing particle tags with stars in a smooth particle hydrodynamic (SPH) simulation. We focus on the spherically averaged density profile of stars accreted from satellite galaxies in a Milky Way (MW)-like system. The stellar profile in the SPH simulation can be recovered accurately by tagging dark matter (DM) particles in the same simulation according to a prescription based on the rank order of particle binding energy. Applying the same prescription to an N-body version of this simulation produces a density profile differing from that of the SPH simulation by ≲10 per cent on average between 1 and 200 kpc. This confirms that particle tagging can provide a faithful and robust approximation to a self-consistent hydrodynamical simulation in this regime (in contradiction to previous claims in the literature). We find only one systematic effect, likely due to the collisionless approximation, namely that massive satellites in the SPH simulation are disrupted somewhat earlier than their collisionless counterparts. In most cases, this makes remarkably little difference to the spherically averaged distribution of their stellar debris. We conclude that, for galaxy formation models that do not predict strong baryonic effects on the present-day DM distribution of MW-like galaxies or their satellites, differences in stellar halo predictions associated with the treatment of star formation and feedback are much more important than those associated with the dynamical limitations of collisionless particle tagging.

  2. Meniscus and beam halo formation in a tandem-type negative ion source with surface production

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2012-06-04

    A meniscus of plasma-beam boundary in H{sup -} ion sources largely affects the extracted H{sup -} ion beam optics. Although it is hypothesized that the shape of the meniscus is one of the main reasons for the beam halo observed in experiments, a physical mechanism of the beam halo formation is not yet fully understood. In this letter, it is first shown by the 2D particle in cell simulation that the H{sup -} ions extracted from the periphery of the meniscus cause a beam halo since the surface produced H{sup -} ions penetrate into the bulk plasma, and, thus, the resultant meniscus has a relatively large curvature.

  3. The Splashback Radius of Halos from Particle Dynamics. II. Dependence on Mass, Accretion Rate, Redshift, and Cosmology

    Science.gov (United States)

    Diemer, Benedikt; Mansfield, Philip; Kravtsov, Andrey V.; More, Surhud

    2017-07-01

    The splashback radius R sp, the apocentric radius of particles on their first orbit after falling into a dark matter halo, has recently been suggested to be a physically motivated halo boundary that separates accreting from orbiting material. Using the Sparta code presented in Paper I, we analyze the orbits of billions of particles in cosmological simulations of structure formation and measure R sp for a large sample of halos that span a mass range from dwarf galaxy to massive cluster halos, reach redshift 8, and include WMAP, Planck, and self-similar cosmologies. We analyze the dependence of R sp/R 200m and M sp/M 200m on the mass accretion rate Γ, halo mass, redshift, and cosmology. The scatter in these relations varies between 0.02 and 0.1 dex. While we confirm the known trend that R sp/R 200m decreases with Γ, the relationships turn out to be more complex than previously thought, demonstrating that R sp is an independent definition of the halo boundary that cannot trivially be reconstructed from spherical overdensity definitions. We present fitting functions for R sp/R 200m and M sp/M 200m as a function of accretion rate, peak height, and redshift, achieving an accuracy of 5% or better everywhere in the parameter space explored. We discuss the physical meaning of the distribution of particle apocenters and show that the previously proposed definition of R sp as the radius of the steepest logarithmic density slope encloses roughly three-quarters of the apocenters. Finally, we conclude that no analytical model presented thus far can fully explain our results.

  4. Pre-asymptotic behavior of single-particle overlap integrals of non-Borromean two-neutron halos

    International Nuclear Information System (INIS)

    Timofeyuk, N.K.; Tostevin, J.A.; Blokhintsev, L.D.

    2003-01-01

    For non-Borromean two-neutron halo nuclei, modifications to the behavior of single-particle overlap integrals will arise due to the correlations of the two interacting nucleons in the halo. An additional contribution to the overlap integral can be obtained using the Feynman diagram approach. This additional term is modeled using a simple local potential model. We show that these modifications may play a role in detailed interpretations of experimental results from single-nucleon knockout, transfer, and other reactions that probe the single-nucleon overlap functions

  5. Particle production by neutrinos

    International Nuclear Information System (INIS)

    Schreiner, P.

    1979-01-01

    A review is given of particle production by neutrinos in charged-current inclusive and exclusive channels. The production rates for various particles in neutrino-nucleon interactions at a beam energy of 25 GeV are compared. The mesons are, of course, dominated by pion production. The p 0 (760) rate is an order of magnitude smaller. Strange and charm pseudoscalar mesons are a further factor of two down in rate. The strange vector mesons are suppressed by more than an order of magnitude relative to K 0 production; however, the charmed D* + (2010) is only a factor of two smaller in rate than the D 0 (1860). With regards to the baryons, most of them are, of course, nucleons. The Λ 0 and Y*(1385) rates are down by one and two orders of magnitudes, respectively. The lower limit on the charmed Σ/sub c/ ++ baryon rate is similar to the Y*(1385) rate. Finally, the quasielastic and one-pion production exclusive channels have about the same cross section as that of the D* + ; associated production of strange particles in the νn → μ - K + Λ channel and the ΔS = +ΔΩ process νp → μ - pK + are down by factors of five and twenty, respectively, compared to the quasielastic cross section

  6. Relaxation from particle production

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Marques-Tavares, Gustavo [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States)

    2016-12-20

    We consider using particle production as a friction force by which to implement a “Relaxion” solution to the electroweak hierarchy problem. Using this approach, we are able to avoid superplanckian field excursions and avoid any conflict with the strong CP problem. The relaxation mechanism can work before, during or after inflation allowing for inflationary dynamics to play an important role or to be completely decoupled.

  7. Production of enhanced beam halos via collective modes and colored noise

    Directory of Open Access Journals (Sweden)

    Ioannis V. Sideris

    2004-10-01

    Full Text Available We investigate how collective modes and colored noise conspire to produce a beam halo with much larger amplitude than could be generated by either phenomenon separately. The collective modes are lowest-order radial eigenmodes calculated self-consistently for a configuration corresponding to a direct-current, cylindrically symmetric, warm-fluid Kapchinskij-Vladimirskij equilibrium. The colored noise arises from unavoidable machine errors and influences the internal space-charge force. Its presence quickly launches statistically rare particles to ever-growing amplitudes by continually kicking them back into phase with the collective-mode oscillations. The halo amplitude is essentially the same for purely radial orbits as for orbits that are initially purely azimuthal; orbital angular momentum has no statistically significant impact. Factors that do have an impact include the amplitudes of the collective modes and the strength and autocorrelation time of the colored noise. The underlying dynamics ensues because the noise breaks the Kolmogorov-Arnol’d-Moser tori that otherwise would confine the beam. These tori are fragile; even very weak noise will eventually break them, though the time scale for their disintegration depends on the noise strength. Both collective modes and noise are therefore centrally important to the dynamics of halo formation in real beams.

  8. Research Note--Should Consumers Use the Halo to Form Product Evaluations?

    OpenAIRE

    Peter Boatwright; Ajay Kalra; Wei Zhang

    2008-01-01

    In purchase situations where attribute information is either missing or difficult to judge, a well-known heuristic that consumers use to form evaluations is the halo effect. The psychology literature has widely considered the halo a reflection of consumers' inability to discriminate between different attributes and have therefore labeled it the "halo error" or the "logical error." The objective of this paper is to offer a rationale for the halo effect. We use a decision-theory framework to sh...

  9. Nuclear molecular halo: the ubiquitous occurrence of van der Waals molecular states near threshold in molecular, nuclear and particle physics

    International Nuclear Information System (INIS)

    Gai, Moshe

    1999-01-01

    The observation of large E1 strength near threshold in the electromagnetic dissociation of 11 Li poses a fundamental question: Is the large E1 strength due to the threshold or is it due to a low lying E1 state? Such molecular cluster states were observed in 18 O and in several nuclei near the drip line. We discuss the nature of the threshold effect as well as review the situation in Molecular (and Particle Physics) where such Molecular States are observed near the dissociation limit. We suggest that the situation in 11 Li is reminiscent of the argon-benzene molecule where the argon atom is loosely bound by a polarization (van der Waals) mechanism and thus leads to a very extended object lying near the dissociation limit. Such states are also suggested to dominate the structure of mesons [α 0 (980), f 0 (975)] and baryons [λ(1405)] with proposed Kaon molecular structure (Dalitz) near threshold. The inspection of such states throughout Physics allows us to gain insight into this phenomenon and suggest that a new collective Molecular Dipole Degree of Freedom plays a major role in the structure of hadrons (halo nuclei, mesons and baryons), and that quantitative tools such as the E1 Molecular Sum Rule are useful for elucidating the nature of the observed low lying E1 strength in halo nuclei. (author)

  10. Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model

    Energy Technology Data Exchange (ETDEWEB)

    Nishioka, S., E-mail: nishioka@ppl.appi.keio.ac.jp; Goto, I.; Hatayama, A. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Miyamoto, K. [School of Natural and Living Sciences Education, Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Fukano, A. [Toshiba, 33 Isogo-chou, Isogo-ku, Yokohama-shi, Kanagawa 235-001 (Japan)

    2014-02-15

    Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result.

  11. Study of plasma meniscus and beam halo in negative ion sources using three dimension in real space and three dimension in velocity space particle in cell model

    International Nuclear Information System (INIS)

    Nishioka, S.; Goto, I.; Hatayama, A.; Miyamoto, K.; Okuda, S.; Fukano, A.

    2014-01-01

    Our previous study by two dimension in real space and three dimension in velocity space-particle in cell model shows that the curvature of the plasma meniscus causes the beam halo in the negative ion sources. The negative ions extracted from the periphery of the meniscus are over-focused in the extractor due to the electrostatic lens effect, and consequently become the beam halo. The purpose of this study is to verify this mechanism with the full 3D model. It is shown that the above mechanism is essentially unchanged even in the 3D model, while the fraction of the beam halo is significantly reduced to 6%. This value reasonably agrees with the experimental result

  12. Particle production at collider energies

    International Nuclear Information System (INIS)

    Geich-Gimbel, C.

    1987-11-01

    Key features of the SPS panti p Collider and the detectors of the UA-experiments involved are dealt with in chapter 2, which includes and accord to the ramping mode of the Collider, which allowed to raise the c.m. energy to 900 GeV in the UA5/2 experiment. The following chapters concentrate on physics results. Starting with a discussion of cross sections and diffraction dissociation in chapter 3 we then continue with a presentation of basic features of particle production such as rapidity and multiplicity distributions in chapter 4. There one of the unexpected findings at Collider energies, the breakdown of the so-called KNO-scaling, and new regularities potentially governing multiplicity distributions, are discussed. The findings about correlations among the final state particles, which may tell about the underlying dynamics of multi-particle production and be relevant to models thereof, are described in due detail in chapter 5. Transverse spectra and their trends with energy are shown in chapter 6. Results on identified particles are collected in a separate chapter in order to stress that this piece of information was an important outcome of the UA5 experiment. (orig./HSI)

  13. Particle production at AGS energies

    International Nuclear Information System (INIS)

    Steadman, S.G.; Rothschild, P.J.; Sung, T.W.; Zachary, D.

    1995-01-01

    The authors discuss particle production from 14.6 A·GeV/c Si and 11.6 A·GeV/c Au projectiles on Al and Au targets. The second-level trigger utilized by E859 allows high precision measurements of K - , bar p, Λ and bar Λ. The bar Λ yield is larger than expected, and a surprisingly large fraction of the bar p's are observed to arise from the decay of bar Λ

  14. Study of heavy particle production

    International Nuclear Information System (INIS)

    1990-01-01

    The collaboration of Columbia University, Fermilab, University of Massachusetts, Mexico and Texas A ampersand M is working on installation of E690 at Fermilab and on analysis of data from the Brookhaven E766 experiment. All the major components of the E690 experiment are in place and final cabling and electronics check outs are being done. In addition to the Brookhaven set-up, the Fermilab set-up has a downstream spectrometer made up of five main ring magnets for detection of a fast 800 GeV proton. This allows us on-line to identify diffraction dissociation of the target proton and to select on the mass produced. We expect copious charm production and some bottom particles. This work should produce papers on charm production at Brookhaven, high mass diffraction dissociation, Lambda-Lambda correlations and polarization of Lamdas

  15. HALO | Arts at CERN

    CERN Multimedia

    Caraban Gonzalez, Noemi

    2018-01-01

    In 2015, the artists participated in a research residency at CERN and began to work with data captured by ATLAS, one of the four detectors at the Large Hadron Collider (LHC) that sits in a cavern 100 metres below ground near the main site of CERN, in Meyrin (Switzerland). For Art Basel, they created HALO, an installation that surrounds visitors with data collected by the ATLAS experiment at the LHC. HALO consists of a 10 m wide cylinder defined by vertical piano wires, within which a 4-m tall screen displays particle collisions. The data also triggers hammers that strike the vertical wires and set up vibrations to create a truly multisensory experience. More info: https://arts.cern/event/unveiling-halo-art-basel

  16. Production of strange particles in hadronization processes

    International Nuclear Information System (INIS)

    Hofmann, W.

    1987-08-01

    Strange particles provide an important tool for the study of the color confinement mechanisms involved in hadronization processes. We review data on inclusive strange-particle production and on correlations between strange particles in high-energy reactions, and discuss phenomenological models for parton fragmentation. 58 refs., 24 figs

  17. Neutron halo in deformed nuclei

    International Nuclear Information System (INIS)

    Zhou Shangui; Meng Jie; Ring, P.; Zhao Enguang

    2010-01-01

    Halo phenomena in deformed nuclei are investigated within a deformed relativistic Hartree Bogoliubov (DRHB) theory. These weakly bound quantum systems present interesting examples for the study of the interdependence between the deformation of the core and the particles in the halo. Contributions of the halo, deformation effects, and large spatial extensions of these systems are described in a fully self-consistent way by the DRHB equations in a spherical Woods-Saxon basis with the proper asymptotic behavior at a large distance from the nuclear center. Magnesium and neon isotopes are studied and detailed results are presented for the deformed neutron-rich and weakly bound nucleus 44 Mg. The core of this nucleus is prolate, but the halo has a slightly oblate shape. This indicates a decoupling of the halo orbitals from the deformation of the core. The generic conditions for the occurrence of this decoupling effects are discussed.

  18. Particle production in the new inflationary cosmology

    International Nuclear Information System (INIS)

    Abbott, L.F.; Farhi, E.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge; Wise, M.B.

    1982-01-01

    Techniques are developed for computing particle production due to the time dependence of a scalar field expectation value during a phase transition. We review the new version of the inflationary universe and discuss baryon production in this model. (orig.)

  19. Heavy particle production at the SSC

    International Nuclear Information System (INIS)

    Brodsky, S.J.; Haber, H.E.; Gunion, J.F.

    1984-03-01

    Predictions for the production of heavy quarks, supersymmetric particles, and other colored systems at high energy due to intrinsic twist-six components in the proton wavefunction are given. We also suggest the possibility of using asymmetric collision energies (e.g., via intersecting rings at the SSC) in order to facilitate the study of forward and diffractive particle production processes. 9 references

  20. Pion production and particle correlations

    International Nuclear Information System (INIS)

    Kristiansson, P.

    1985-10-01

    Intermediate energy heavy ion collisions have been studied using the carbon-beam produced at the CERN SC-accelerator. Cross-sections for π + and π - have been measured over a wide range of large angles at 60, 75 and 86 MeV/nucleon. The yields and shapes are compared to a nucleon-nucleon scattering approach, which underestimates the yields by orders of magnitude. The π - /π + -ratio observed is close to unity for 12 C + 12 C, but the enhancement for 12 C + 208 Pb is much larger than expected from the neutron excess in 208 Pb. Large-angle light-particle correlations for 86 MeV/nucleon carbon induced reactions on different targets (C, Al, Cu, Au) have been studied. An excess of correlations is observed in the particle-particle scattering plane. The strength of this effect increases with observed particle mass and decreases with target mass. (author)

  1. Gravitational particle production in braneworld cosmology.

    Science.gov (United States)

    Bambi, C; Urban, F R

    2007-11-09

    Gravitational particle production in a time variable metric of an expanding universe is efficient only when the Hubble parameter H is not too small in comparison with the particle mass. In standard cosmology, the huge value of the Planck mass M{Pl} makes the mechanism phenomenologically irrelevant. On the other hand, in braneworld cosmology, the expansion rate of the early Universe can be much faster, and many weakly interacting particles can be abundantly created. Cosmological implications are discussed.

  2. Charm and particle production in neutrino interactions

    International Nuclear Information System (INIS)

    Cazzoli, E.G.; Cnops, A.M.; Connolly, P.L.; Louttit, R.I.; Murtagh, M.J.; Palmer, R.B.; Samios, N.P.; Tso, T.T.; Williams, H.H.

    1976-01-01

    Ten strange particles were observed in a total of 1086 charged current neutrino interactions obtained in the analysis of 482,000 pictures taken in the Brookhaven Cryogenic 7' Bubble Chamber filled with hydrogen and deuterium. Details of these events are presented together with rates for associated strange particle and ΔS = +-ΔQ production in neutrino interactions

  3. Plasma analog of particle-pair production

    International Nuclear Information System (INIS)

    Tsidulko, Yu.A.; Berk, H.L.

    1996-09-01

    It is shown that the plasma axial shear flow instability satisfies the Klein-Gordon equation. The plasma instability is then shown to be analogous to spontaneous particle-pair production when a potential energy is present that is greater than twice the particle rest mass energy. Stability criteria can be inferred based on field theoretical conservation laws

  4. Particle production in higher derivative theory

    Indian Academy of Sciences (India)

    Lemaitre–Robertson–Walker cosmological model during the early stages of the universe is analysed in the framework of higher derivative theory. The universe has been considered as an open thermodynamic system where particle production ...

  5. Production method of α particles

    International Nuclear Information System (INIS)

    Prevot, F.

    1953-01-01

    It is proposed a method to get an intense beam of α particles. With a source of ordinary ions, we form a helium beam, once ionized, it is accelerated with an energy of a few hundreds of keV. While crossing a matter any that can be a thin leaf or a gaseous blade, the second electron of helium is pulled with a yield that only depends on the energy of the beam of helium and that is equal to 1/2 for 650 keV. (author) [fr

  6. Weak strange particle production: advantages and difficulties

    International Nuclear Information System (INIS)

    Angelescu, Tatiana; Baker, O.K.

    2002-01-01

    Electromagnetic strange particle production developed at Jefferson Laboratory was an important source of information on strange particle electromagnetic formfactors and induced and transferred polarization. The high quality of the beam and the detection techniques involved could be an argument for detecting strange particles in weak interactions and answer questions about cross sections, weak formfactors, neutrino properties, which have not been investigated yet. The paper analyses some aspects related to the weak lambda production and detection with the Hall C facilities at Jefferson Laboratory and the limitations in measuring the weak interaction quantities. (authors)

  7. Tracking the LHC halo

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In the LHC, beams of 25-ns-spaced proton bunches travel at almost the speed of light and pass through many different devices installed along the ring that monitor their properties. During their whirling motion, beam particles might interact with the collimation instrumentation or with residual gas in the vacuum chambers and this creates the beam halo – an annoying source of background for the physics data. Newly installed CMS sub-detectors are now able to monitor it.   The Beam Halo Monitors (BHM) are installed around the CMS rotating shielding. The BHM are designed and built by University of Minnesota, CERN, Princeton University, INFN Bologna and the National Technical University of Athens. (Image: Andrea Manna). The Beam Halo Monitor (BHM) is a set of 20 Cherenkov radiators – 10-cm-long quartz crystals – installed at each end of the huge CMS detector. Their design goal is to measure the particles that can cause the so-called “machine-induced...

  8. Reionization histories of Milky Way mass halos

    International Nuclear Information System (INIS)

    Li, Tony Y.; Wechsler, Risa H.; Abel, Tom; Alvarez, Marcelo A.

    2014-01-01

    We investigate the connection between the reionization era and the present-day universe by examining the mass reionization histories of z = 0 dark matter halos. In a 600 3 Mpc 3 volume, we combine a dark matter N-body simulation with a three-dimensional seminumerical reionization model. This tags each particle with a reionization redshift, so that individual present-day halos can be connected to their reionization histories and environments. We find that the vast majority of present-day halos with masses larger than ∼ few × 10 11 M ☉ reionize earlier than the rest of the universe. We also find significant halo-to-halo diversity in mass reionization histories, and find that in realistic inhomogeneous models, the material within a given halo is not expected to reionize at the same time. In particular, the scatter in reionization times within individual halos is typically larger than the scatter among halos. From our fiducial reionization model, we find that the typical 68% scatter in reionization times within halos is ∼115 Myr for 10 12±0.25 M ☉ halos, decreasing slightly to ∼95 Myr for 10 15±0.25 M ☉ halos. We find a mild correlation between reionization history and environment: halos with shorter reionization histories are typically in more clustered environments, with the strongest trend on a scale of ∼20 Mpc. Material in Milky Way mass halos with short reionization histories is preferentially reionized in relatively large H II regions, implying reionization mostly by sources external to the progenitors of the present-day halo. We investigate the impact on our results of varying the reionization model parameters, which span a range of reionization scenarios with varying timing and morphology.

  9. Gravitational Particle Production and the Moduli Problem

    CERN Document Server

    Felder, G; Linde, Andrei D; Felder, Gary; Kofman, Lev; Linde, Andrei

    2000-01-01

    A theory of gravitational production of light scalar particles during and after inflation is investigated. We show that in the most interesting cases where long-wavelength fluctuations of light scalar fields can be generated during inflation, these fluctuations rather than quantum fluctuations produced after inflation give the dominant contribution to particle production. In such cases a simple analytical theory of particle production can be developed. Application of our results to the theory of quantum creation of moduli fields demonstrates that if the moduli mass is smaller than the Hubble constant then these fields are copiously produced during inflation. This gives rise to the cosmological moduli problem even if there is no homogeneous component of the classical moduli field in the universe. To avoid this version of the moduli problem it is necessary for the Hubble constant H during the last stages of inflation and/or the reheating temperature T_R after inflation to be extremely small.

  10. Perturbative Universality in Soft Particle Production

    CERN Document Server

    Khoze, V A; Ochs, Wolfgang; Khoze, Valery A.; Lupia, Sergio; Ochs, Wolfgang

    1998-01-01

    The spectrum of partons in a QCD jet becomes independent of the primary energy in the low momentum limit. This follows within the perturbative QCD from the colour coherence in soft gluon branching. Remarkably, the hadrons follow such behaviour closely, suggesting the parton hadron duality picture to be appropriate also for the low momentum particles. More generally, this scaling property holds for particles of low transverse and arbitrary longitudinal momentum, which explains an old experimental observation (``fan invariance''). Further tests of the perturbatively based picture for soft particle production are proposed for three-jet events in e+e- annihilation and di-jet production events in gamma p, gamma-gamma and p\\bar p collisions. They are based upon the difference in the intensity of the soft radiation from primary q\\bar q and gg antennae.

  11. Main Injector Particle Production Experiment Status

    International Nuclear Information System (INIS)

    Lebedev, Andre

    2007-01-01

    MIPP (FNAL-E907) is a large acceptance spectrometer to measure hadronic particle production - TPC and wire chambers to measure track parameters - TPC dE/dx, ToF, differential Cherenkov and ring imaging Cherenkov give π/K/p separation up to 100 GeV/c

  12. Particle production in higher derivative theory

    Indian Academy of Sciences (India)

    Cosmological models; particle production; higher derivative theory of gravitation. PACS No. 98.80. 1. ... is of singular models where the cosmic expansion is driven by the big-bang impulse; all ... According to Gibbs integrability condition, one cannot independently specify an equa- .... [3] B Hartle and S W Hawking Phys. Rev.

  13. Interactions between massive dark halos and warped disks

    NARCIS (Netherlands)

    Kuijken, K; Persic, M; Salucci, P

    1997-01-01

    The normal mode theory for warping of galaxy disks, in which disks are assumed to be tilted with respect to the equator of a massive, flattened dark halo, assumes a rigid, fixed halo. However, consideration of the back-reaction by a misaligned disk on a massive particle halo shows there to be strong

  14. Exotic nuclei: Halos

    Energy Technology Data Exchange (ETDEWEB)

    Orr, Nigel [Lab. de Physique Corpusculaire, Caen Univ., 14 (France); Collaboration: La Direction des Sciences de la Matiere du CEA (FR); Le Fonds National de la Recherche Scientifique de Belgique (BE)

    1998-12-31

    A brief overview of the nuclear halo is presented. Following some historical remarks the general characteristics of the halo systems are discussed with reference to a simple model. The conditions governing the formation of halos are also explored, as are two subjects of current interest - low-lying resonances of halo nucleon correlations. (author) 54 refs., 16 figs., 1 tabs.

  15. Self-consistent beam halo studies ampersand halo diagnostic development in a continuous linear focusing channel

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1994-01-01

    Beam halos are formed via self-consistent motion of the beam particles. Interactions of single particles with time-varying density distributions of other particles are a major source of halo. Aspects of these interactions are studied for an initially equilibrium distribution in a radial, linear, continuous focusing system. When there is a mismatch, it is shown that in the self-consistent system, there is a threshold in space-charge and mismatch, above which a halo is formed that extends to ∼1.5 times the initial maximum mismatch radius. Tools are sought for characterizing the halo dynamics. Testing the particles against the width of the mismatch driving resonance is useful for finding a conservative estimate of the threshold. The exit, entering and transition times, and the time evolution of the halo, are also explored using this technique. Extension to higher dimensions is briefly discussed

  16. The Lithium isotope ratio in Population II halo dwarfs: A proposed test of the late decaying massive particle nucleosynthesis scenario

    International Nuclear Information System (INIS)

    Brown, L.; Schramm, D.N.

    1988-02-01

    It is shown that observations of the Lithium isotope ratio in high surface temperature Population II stars may be critical to cosmological nucleosynthesis models. In particular, decaying particle scenarios as derived in some supersymmetric models may stand or fall with such observations. 15 refs., 3 figs., 2 tabs

  17. Nuclear fuel particle and method of production

    International Nuclear Information System (INIS)

    Wagner-Loffler, M.

    1975-01-01

    The core consisting of fuel oxide (UO 2 or Th or Pu oxide) of a fuel particle coated with carbon-contained material is enriched with a small addition (max 6 wt.%) of a Ba or Sr compound (atomic ratio for nuclear fuel oxide Ba being 5 - 10 : 1) which is to prevent fission products breaking the protective carbon and/or silicon carbide coating; the Ba or Sr molybdate generated is to reduce the pressure of the carbon dioxide produced. Methods to manufacture such nuclear fuel particles are proposed where 1) an agglomerisation and shaping of the spheres in a fast cycling bowle and 2) a formation of drops from a colloidal solution which are made to congeal in a liquid paraffin column, take place followed by the pyrolytic coating of the particles. (UWI/LH) [de

  18. Nongaussian Features from Inflationary Particle Production

    International Nuclear Information System (INIS)

    Barnaby, Neil

    2010-01-01

    The inflaton field can be expected to couple to a number of additional fields whose energy density does not play any significant role in driving inflation. Such couplings may lead to isolated bursts of particle production during inflation, for example via parametric resonance or a phase transition, and leave observable imprints in the cosmological fluctuations. I illustrate this effect for a simple prototype interaction g 2 (φ - φ 0 ) 2 χ between the inflaton, φ, and iso-inflaton, χ. Using both classical lattice simulations and analytical quantum field theory computations, I show that this mechanism generates localized bump-like features in the power spectrum and also a completely new type of nongaussianity. Observations are consistent with relatively large features of this type and the nongaussianity from particle production may be observable in future missions.

  19. Neutral-particle-beam production and injection

    International Nuclear Information System (INIS)

    Post, D.; Pyle, R.

    1982-07-01

    This paper is divided into two sections: the first is a discussion of the interactions of neutral beams with confined plasmas, the second is concerned with the production and diagnosis of the neutral beams. In general we are dealing with atoms, molecules, and ions of the isotopes of hydrogen, but some heavier elements (for example, oxygen) will be mentioned. The emphasis will be on single-particle collisions; selected atomic processes on surfaces will be included

  20. Particle production in heavy ion collisions

    International Nuclear Information System (INIS)

    Braun-Munzinger, P.; Redlich, K.; Wroclaw Univ.; Stachel, J.

    2003-04-01

    The status of thermal model descriptions of particle production in heavy ion collisions is presented. We discuss the formulation of statistical models with different implementation of the conservation laws and indicate their applicability in heavy ion and elementary particle collisions. We analyze experimental data on hadronic abundances obtained in ultra-relativistic heavy ion collisions, in a very broad energy range starting from RHIC/BNL (√(s) = 200 A GeV), SPS/CERN (√(s) ≅ 20 A GeV) up to AGS/BNL (√(s) ≅ 5 A GeV) and SIS/GSI (√(s) ≅ 2 A GeV) to test equilibration of the fireball created in the collision. We argue that the statistical approach provides a very satisfactory description of experimental data covering this wide energy range. Any deviations of the model predictions from the data are indicated. We discuss the unified description of particle chemical freeze-out and the excitation functions of different particle species. At SPS and RHIC energy the relation of freeze-out parameters with the QCD phase boundary is analyzed. Furthermore, the application of the extended statistical model to quantitative understanding of open and hidden charm hadron yields is considered. (orig.)

  1. Leading Particle Production in Light Flavour Jets

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, Gideon; Allison, J; Anderson, K J; Arcelli, S; Asai, S; Ashby, S F; Axen, D A; Azuelos, Georges; Bailey, I; Ball, A H; Barberio, E; Barlow, R J; Batley, J Richard; Baumann, S; Behnke, T; Bell, K W; Bella, G; Bellerive, A; Bentvelsen, Stanislaus Cornelius Maria; Bethke, Siegfried; Betts, S; Biebel, O; Biguzzi, A; Bloodworth, Ian J; Bock, P; Böhme, J; Boeriu, O; Bonacorsi, D; Boutemeur, M; Braibant, S; Bright-Thomas, P G; Brigliadori, L; Brown, R M; Burckhart, Helfried J; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Ciocca, C; Clarke, P E L; Clay, E; Cohen, I; Conboy, J E; Cooke, O C; Couchman, J; Couyoumtzelis, C; Coxe, R L; Cuffiani, M; Dado, S; Dallavalle, G M; Dallison, S; Davis, R; de Roeck, A; Dervan, P J; Desch, Klaus; Dienes, B; Dixit, M S; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Estabrooks, P G; Etzion, E; Fabbri, Franco Luigi; Fanfani, A; Fanti, M; Faust, A A; Feld, L; Ferrari, P; Fiedler, F; Fierro, M; Fleck, I; Frey, A; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gaycken, G; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Gingrich, D M; Glenzinski, D A; Goldberg, J; Gorn, W; Grandi, C; Graham, K; Gross, E; Grunhaus, Jacob; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Harder, K; Harel, A; Hargrove, C K; Harin-Dirac, M; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hobson, P R; Höcker, Andreas; Hoffman, K; Homer, R James; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Igo-Kemenes, P; Imrie, D C; Ishii, K; Jacob, F R; Jawahery, A; Jeremie, H; Jimack, Martin Paul; Jones, C R; Jovanovic, P; Junk, T R; Kanaya, N; Kanzaki, J I; Karapetian, G V; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kim, D H; Klier, A; Kobayashi, T; Kobel, M; Kokott, T P; Kolrep, M; Komamiya, S; Kowalewski, R V; Kress, T; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Kyberd, P; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Lauber, J; Lawson, I; Layter, J G; Lellouch, Daniel; Letts, J; Levinson, L; Liebisch, R; Lillich, J; List, B; Littlewood, C; Lloyd, A W; Lloyd, S L; Loebinger, F K; Long, G D; Losty, Michael J; Lü, J; Ludwig, J; Macchiolo, A; MacPherson, A L; Mader, W F; Mannelli, M; Marcellini, S; Marchant, T E; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Méndez-Lorenzo, P; Merritt, F S; Mes, H; Meyer, I; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Montanari, A; Mori, T; Nagai, K; Nakamura, I; Neal, H A; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Okpara, A N; Oreglia, M J; Orito, S; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, James L; Plane, D E; Poli, B; Polok, J; Przybycien, M B; Quadt, A; Rembser, C; Rick, Hartmut; Robins, S A; Rodning, N L; Roney, J M; Rosati, S; Roscoe, K; Rossi, A M; Rozen, Y; Runge, K; Runólfsson, O; Rust, D R; Sachs, K; Saeki, T; Sahr, O; Sang, W M; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schmitt, S; Schöning, A; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Skuja, A; Smith, A M; Snow, G A; Sobie, Randall J; Söldner-Rembold, S; Spagnolo, S; Sproston, M; Stahl, A; Stephens, K; Stoll, K; Strom, D; Ströhmer, R; Surrow, B; Talbot, S D; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomas, J; Thomson, M A; Torrence, E; Towers, S; Trefzger, T M; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Van Kooten, R; Vannerem, P; Verzocchi, M; Voss, H; Wäckerle, F; Waller, D; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wetterling, D; White, J S; Wilson, G W; Wilson, J A; Wyatt, T R; Yamashita, S; Zacek, V; Zer-Zion, D

    2000-01-01

    The energy distribution and type of the particle with the highest momentum in quark jets are determined for each of the five quark flavours making only minimal model assumptions. The analysis is based on a large statistics sample of hadronic Z0 decays collected with the OPAL detector at the LEP e+e- collider. These results provide a basis for future studies of light flavour production at other centre-of-mass energies. We use our results to study the hadronisation mechanism in light flavour jets and compare the data to the QCD models JETSET and HERWIG. Within the JETSET model we also directly determine the suppression of strange quarks to be gamma_s=0.422+-0.049 (stat.)+-0.059 (syst.) by comparing the production of charged and neutral kaons in strange and non-strange light quark events. Finally we study the features of baryon production.

  2. V0 particle production studies at LHCb

    CERN Multimedia

    Knecht, M

    2009-01-01

    Although QCD is firmly established as the fundamental theory of strong interactions, the fragmentation process from partons into hadrons is still poorly understood. Phenomenological models tuned to Tevatron data show significant differences when extrapolated to LHC energies. The hadronization process can be probed at the LHC by studying V0 production, i.e. the production of KS mesons and Lambda hyperons. The LHCb experiment, with a rapidity range complementary to that of the other LHC detectors, offers a particularly interesting environment, covering the forward region where the existing models are very tunable but lack predictive power. The first 100 millions minimum bias events at LHCb will already provide a high-statistics and high-purity V0 sample. Measurements will include differential cross sections and production ratios for different strange particles as a function of rapidity and transverse momentum. The analysis can naturally be extended to cover heavier hyperons as well, and eventually lead, w...

  3. ORIGAMI: DELINEATING HALOS USING PHASE-SPACE FOLDS

    Energy Technology Data Exchange (ETDEWEB)

    Falck, Bridget L.; Neyrinck, Mark C.; Szalay, Alexander S. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2012-08-01

    We present the ORIGAMI method of identifying structures, particularly halos, in cosmological N-body simulations. Structure formation can be thought of as the folding of an initially flat three-dimensional manifold in six-dimensional phase space. ORIGAMI finds the outer folds that delineate these structures. Halo particles are identified as those that have undergone shell-crossing along three orthogonal axes, providing a dynamical definition of halo regions that is independent of density. ORIGAMI also identifies other morphological structures: particles that have undergone shell-crossing along 2, 1, or 0 orthogonal axes correspond to filaments, walls, and voids, respectively. We compare this method to a standard friends-of-friends halo-finding algorithm and find that ORIGAMI halos are somewhat larger, more diffuse, and less spherical, though the global properties of ORIGAMI halos are in good agreement with other modern halo-finding algorithms.

  4. ORIGAMI: DELINEATING HALOS USING PHASE-SPACE FOLDS

    International Nuclear Information System (INIS)

    Falck, Bridget L.; Neyrinck, Mark C.; Szalay, Alexander S.

    2012-01-01

    We present the ORIGAMI method of identifying structures, particularly halos, in cosmological N-body simulations. Structure formation can be thought of as the folding of an initially flat three-dimensional manifold in six-dimensional phase space. ORIGAMI finds the outer folds that delineate these structures. Halo particles are identified as those that have undergone shell-crossing along three orthogonal axes, providing a dynamical definition of halo regions that is independent of density. ORIGAMI also identifies other morphological structures: particles that have undergone shell-crossing along 2, 1, or 0 orthogonal axes correspond to filaments, walls, and voids, respectively. We compare this method to a standard friends-of-friends halo-finding algorithm and find that ORIGAMI halos are somewhat larger, more diffuse, and less spherical, though the global properties of ORIGAMI halos are in good agreement with other modern halo-finding algorithms.

  5. Remapping simulated halo catalogues in redshift space

    OpenAIRE

    Mead, Alexander; Peacock, John

    2014-01-01

    We discuss the extension to redshift space of a rescaling algorithm, designed to alter the effective cosmology of a pre-existing simulated particle distribution or catalogue of dark matter haloes. The rescaling approach was initially developed by Angulo & White and was adapted and applied to halo catalogues in real space in our previous work. This algorithm requires no information other than the initial and target cosmological parameters, and it contains no tuned parameters. It is shown here ...

  6. Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

    Science.gov (United States)

    Andreae, Meinrat O.; Afchine, Armin; Albrecht, Rachel; Amorim Holanda, Bruna; Artaxo, Paulo; Barbosa, Henrique M. J.; Borrmann, Stephan; Cecchini, Micael A.; Costa, Anja; Dollner, Maximilian; Fütterer, Daniel; Järvinen, Emma; Jurkat, Tina; Klimach, Thomas; Konemann, Tobias; Knote, Christoph; Krämer, Martina; Krisna, Trismono; Machado, Luiz A. T.; Mertes, Stephan; Minikin, Andreas; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; Rosenfeld, Daniel; Sauer, Daniel; Schlager, Hans; Schnaiter, Martin; Schneider, Johannes; Schulz, Christiane; Spanu, Antonio; Sperling, Vinicius B.; Voigt, Christiane; Walser, Adrian; Wang, Jian; Weinzierl, Bernadett; Wendisch, Manfred; Ziereis, Helmut

    2018-01-01

    Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German-Brazilian cooperative aircraft campaign ACRIDICON-CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September-October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable

  7. Halo Mitigation Using Nonlinear Lattices

    CERN Document Server

    Sonnad, Kiran G

    2005-01-01

    This work shows that halos in beams with space charge effects can be controlled by combining nonlinear focusing and collimation. The study relies on Particle-in-Cell (PIC) simulations for a one dimensional, continuous focusing model. The PIC simulation results show that nonlinear focusing leads to damping of the beam oscillations thereby reducing the mismatch. It is well established that reduced mismatch leads to reduced halo formation. However, the nonlinear damping is accompanied by emittance growth causing the beam to spread in phase space. As a result, inducing nonlinear damping alone cannot help mitigate the halo. To compensate for this expansion in phase space, the beam is collimated in the simulation and further evolution of the beam shows that the halo is not regenerated. The focusing model used in the PIC is analysed using the Lie Transform perturbation theory showing that by averaging over a lattice period, one can reuduce the focusing force to a form that is identical to that used in the PIC simula...

  8. Strange particle production from quark matter droplets

    International Nuclear Information System (INIS)

    Werner, K.; Hladik, M.

    1995-01-01

    We recently introduced new methods to study ultrarelativistic nuclear scattering by providing a link between the string model approach and a thermal description. The string model is used to provide information about fluctuations in energy density. Regions of high energy density are considered to be quark matter droplets and treated macroscopically. At SPS energies, we find mainly medium size droplets---with energies up to few tens of Gev. A key issue is the microcanonical treatment of individual quark matter droplets. Each droplet hadronizes instantaneously according to the available n-body phase space. Due to the huge number of possible hadron configurations, special Monte Carlo techniques have been developed to calculate this disintegration. We present results concerning the production of strange particles from such a hadronization as compared to string decay. copyright 1995 American Institute of Physics

  9. A beam halo event of the ATLAS Experiment

    CERN Multimedia

    ATLAS, Experiment

    2014-01-01

    Beam halo events: These occur as a single beam of protons is circulating in one direction in LHC, just passing through ATLAS. An outlier particle hits a part of the detector causing a spray of particles.

  10. Pair production of arbitrary spin particles by electromagnetic fields

    International Nuclear Information System (INIS)

    Kruglov, S.I.

    2006-01-01

    The exact solutions of the wave equation for arbitrary spin particles in the field of the soliton-like electric impulse were obtained. The differential probability of pair production of particles by electromagnetic fields has been evaluated on the basis of the exact solutions. As a particular case, the particle pair production in the constant and uniform electric field were studied

  11. Dark matter haloes: a multistream view

    Science.gov (United States)

    Ramachandra, Nesar S.; Shandarin, Sergei F.

    2017-09-01

    Mysterious dark matter constitutes about 85 per cent of all masses in the Universe. Clustering of dark matter plays a dominant role in the formation of all observed structures on scales from a fraction to a few hundreds of Mega-parsecs. Galaxies play a role of lights illuminating these structures so they can be observed. The observations in the last several decades have unveiled opulent geometry of these structures currently known as the cosmic web. Haloes are the highest concentrations of dark matter and host luminous galaxies. Currently the most accurate modelling of dark matter haloes is achieved in cosmological N-body simulations. Identifying the haloes from the distribution of particles in N-body simulations is one of the problems attracting both considerable interest and efforts. We propose a novel framework for detecting potential dark matter haloes using the field unique for dark matter-multistream field. The multistream field emerges at the non-linear stage of the growth of perturbations because the dark matter is collisionless. Counting the number of velocity streams in gravitational collapses supplements our knowledge of spatial clustering. We assume that the virialized haloes have convex boundaries. Closed and convex regions of the multistream field are hence isolated by imposing a positivity condition on all three eigenvalues of the Hessian estimated on the smoothed multistream field. In a single-scale analysis of high multistream field resolution and low softening length, the halo substructures with local multistream maxima are isolated as individual halo sites.

  12. Isospin conservation in many-particle production

    International Nuclear Information System (INIS)

    Reinders, L.J.

    1976-01-01

    Exact isospin conservation is incorporated into independent pion emission models at high energies. A multipion wave function is constructed which is an eigen state of the isospin operators I 2 and I 3 , with the only restriction being that the wave function is completely symmetric in all momentum variables. In this way isospin conservation can account for the observed broadening of the changed particle distribution, but not the positive changed-neutral correlation for pp and π + p inelastic scattering. The author shows that these difficulties can be overcome by the introduction of clusters. Using the generating function technique a general formalism is given for the production of isospin-zero and isospin-one clusters. In the simplest case of the uncorrelated production of clusters and their subsequent isotropic decay, the topological cross-sections for proton-proton scattering could be fitted fairly well resulting also in a possitive changed-neutral correlation. The number of clusters is approximately constant in an energy range between 110 and 400 GeV

  13. Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 2: The Chaco Halo, Mesa Verde, Pajarito Plateau/Bandelier, and Zuni Archaeological Regions

    Science.gov (United States)

    Benson, L.V.

    2011-01-01

    Chemical and nutrient analyses of 471 soil samples from 161 sites within four archaeological regions (Pajarito Plateau/Bandelier, Zuni, Mesa Verde, and the Chaco Halo) were combined with historical climate data in order to evaluate the agricultural productivity of each region. In addition, maize productivity and field-life calculations were performed using organic-nitrogen (N) values from the upper 50 cm of soil in each region and a range (1-3%/year) of N-mineralization rates. The endmember values of this range were assumed representative of dry and wet climate states. With respect to precipitation and heat, the Pajarito Plateau area has excellent agricultural potential; the agricultural potentials of the Zuni and Mesa Verde regions are good; and the agricultural potential of the Chaco Halo is poor. Calculations of N mineralization and field life indicate that Morfield Valley in Mesa Verde should be able to provide 10 bu/ac of maize for decades (without the addition of N) when organic N-mineralization rates exceed 2%. Productivity and field-life potential decrease in the following order: Zuni, Mesa Verde, Bandelier, Chaco Halo. The Chaco Halo is very unproductive; e. g., 10 bushels per acre can be achieved within the Halo only from soils having the highest organic N concentration (third quartile) and which undergo the highest rate (3%) of N mineralization. ?? 2010 US Government.

  14. MINIMARS interim report appendix halo model and computer code

    International Nuclear Information System (INIS)

    Santarius, J.F.; Barr, W.L.; Deng, B.Q.; Emmert, G.A.

    1985-01-01

    A tenuous, cool plasma called the halo shields the core plasma in a tandem mirror from neutral gas and impurities. The neutral particles are ionized and then pumped by the halo to the end tanks of the device, since flow of plasma along field lines is much faster than radial flow. Plasma reaching the end tank walls recombines, and the resulting neutral gas is vacuum pumped. The basic geometry of the MINIMARS halo is shown. For halo modeling purposes, the core plasma and cold gas regions may be treated as single radial zones leading to halo source and sink terms. The halo itself is differential into two major radial zones: halo scraper and halo dump. The halo scraper zone is defined by the radial distance required for the ion end plugging potential to drop to the central cell value, and thus have no effect on axial confinement; this distance is typically a sloshing plug ion Larmor diameter. The outer edge of the halo dump zone is defined by the last central cell flux tube to pass through the choke coil. This appendix will summarize the halo model that has been developed for MINIMARS and the methodology used in implementing that model as a computer code

  15. Particle production in a gravitational wave background

    Science.gov (United States)

    Jones, Preston; McDougall, Patrick; Singleton, Douglas

    2017-03-01

    We study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g +g →γ +γ . Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero vacuum expectation value (similar to what occurs in the Higgs mechanism) and a nonzero current. We associate this with the production of scalar field quanta by the gravitational field. This effect has potential consequences for the attenuation of gravitational waves since the massless field is being produced at the expense of the gravitational field. This is related to the time-dependent Schwinger effect, but with the electric field replaced by the gravitational wave background and the electron/positron field quanta replaced by massless scalar "photons." Since the produced scalar quanta are massless there is no exponential suppression, as occurs in the Schwinger effect due to the electron mass.

  16. Self-consistent construction of virialized wave dark matter halos

    Science.gov (United States)

    Lin, Shan-Chang; Schive, Hsi-Yu; Wong, Shing-Kwong; Chiueh, Tzihong

    2018-05-01

    Wave dark matter (ψ DM ), which satisfies the Schrödinger-Poisson equation, has recently attracted substantial attention as a possible dark matter candidate. Numerical simulations have, in the past, provided a powerful tool to explore this new territory of possibility. Despite their successes in revealing several key features of ψ DM , further progress in simulations is limited, in that cosmological simulations so far can only address formation of halos below ˜2 ×1011 M⊙ and substantially more massive halos have become computationally very challenging to obtain. For this reason, the present work adopts a different approach in assessing massive halos by constructing wave-halo solutions directly from the wave distribution function. This approach bears certain similarities with the analytical construction of the particle-halo (cold dark matter model). Instead of many collisionless particles, one deals with one single wave that has many noninteracting eigenstates. The key ingredient in the wave-halo construction is the distribution function of the wave power, and we use several halos produced by structure formation simulations as templates to determine the wave distribution function. Among different models, we find the fermionic King model presents the best fits and we use it for our wave-halo construction. We have devised an iteration method for constructing the nonlinear halo and demonstrate its stability by three-dimensional simulations. A Milky Way-sized halo has also been constructed, and the inner halo is found to be flatter than the NFW profile. These wave-halos have small-scale interferences both in space and time producing time-dependent granules. While the spatial scale of granules varies little, the correlation time is found to increase with radius by 1 order of magnitude across the halo.

  17. Collisionless analogs of Riemann S ellipsoids with halo

    International Nuclear Information System (INIS)

    Abramyan, M.G.

    1987-01-01

    A spheroidal halo ensures equilibrium of the collisionless analogs of the Riemann S ellipsoids with oscillations of the particles along the direction of their rotation. Sequences of collisionless triaxial ellipsoids begin and end with dynamically stable members of collisionless embedded spheroids. Both liquid and collisionless Riemann S ellipsoids with weak halo have properties that resemble those of bars of SB galaxies

  18. Thermal and nonthermal particle production without event horizons

    International Nuclear Information System (INIS)

    Sanchez, N.

    1979-01-01

    Usually, particle production in accelerated frames is discussed in connection with the presence of event horizons and with a planckian spectrum. Accelerated frames without event horizons, where particle production takes place with thermal as well as nonthermal distributions, are constructed. (Auth.)

  19. Cumulative particle production in the quark recombination model

    International Nuclear Information System (INIS)

    Gavrilov, V.B.; Leksin, G.A.

    1987-01-01

    Production of cumulative particles in hadron-nuclear inteactions at high energies is considered within the framework of recombination quark model. Predictions for inclusive cross sections of production of cumulative particles and different resonances containing quarks in s state are made

  20. Effect of limestone particle size on egg production and eggshell ...

    African Journals Online (AJOL)

    Different limestone particle sizes had no effect on any of the tested egg production and eggshell quality parameters. These results suggested that larger particles limestone are not necessarily essential to provide sufficient Ca2+ to laying hens for egg production and eggshell quality at end-of-lay, provided that the dietary Ca ...

  1. Neutron halos in hypernuclei

    CERN Document Server

    Lue, H F; Meng, J; Zhou, S G

    2003-01-01

    Properties of single-LAMBDA and double-LAMBDA hypernuclei for even-N Ca isotopes ranging from the proton dripline to the neutron dripline are studied using the relativistic continuum Hartree-Bogolyubov theory with a zero-range pairing interaction. Compared with ordinary nuclei, the addition of one or two LAMBDA-hyperons lowers the Fermi level. The predicted neutron dripline nuclei are, respectively, sup 7 sup 5 subLAMBDA Ca and sup 7 sup 6 sub 2 subLAMBDA Ca, as the additional attractive force provided by the LAMBDA-N interaction shifts nuclei from outside to inside the dripline. Therefore, the last bound hypernuclei have two more neutrons than the corresponding ordinary nuclei. Based on the analysis of two-neutron separation energies, neutron single-particle energy levels, the contribution of continuum and nucleon density distribution, giant halo phenomena due to the pairing correlation, and the contribution from the continuum are suggested to exist in Ca hypernuclei similar to those that appear in ordinary ...

  2. A cascade mechanism of three-particle resonance production

    International Nuclear Information System (INIS)

    Badalyan, A.M.; Polikarpov, M.I.; Simonov, Yu.A.

    1976-01-01

    We study the mechanism of the three-particle resonance production in a system consisting of a two-particle resonance and of one particle, the resonance and the particle permanently exchanging the decay product particle. The N/D method is used to show that the solution of the unitarity for the resonance-particle amplitude reduces to solving a one-dimensional nonsingular integral equation for the denominator of the amplitude D(y). The contribution from the right-hand cut of the exchange decay diagram is considered explicitly and the final equation contains only the integral over an arbitrary left-hand cut as in the case of the interaction amplitude of stable particles. It is as well shown that if only the right-hand cut is present, than the denominator D(y) for L=0 has no singularities, whereas the amplitude may have virtual or real poles at L=1

  3. Carbonaceous Particles Production in a Sputtering Discharge

    International Nuclear Information System (INIS)

    Dominique, Claire; Sant, Marco; Arnas, Cecile

    2005-01-01

    Spherical dust particles have been produced in argon glow discharge by sputtering of a graphite cathode. Their size varies from 40 to 200 nm depending on the distance between the two electrodes and the largest ones have a cauliflower shape. Simulations giving the evolution of the energy distribution of sputtered carbon atoms suggest a mechanism of growth by carbon vapour condensation. The chemical composition and structure of particles have been investigated by infrared spectroscopy and appear to be a complex arrangement of the carbon atoms and hetero-atoms

  4. On slow particle production in hadron-nucleus interactions

    International Nuclear Information System (INIS)

    Stenlund, E.; Otterlund, I.

    1982-01-01

    A model for slow particle production in hadron-nucleus interactions is presented. The model succesfully predicts correlations between the number of knock-on particles and the number of particles associated with the evaporation process as well as correlations with the number of collisions, ν, between the incident hadron and the nucleons inside the target nucleus. The model provides two independent possibilities to determine the number of primary intranuclear collisions, ν, i.e. by its correlation to the number of knock-on particles or to the number of evaporated particles. The good agreement indicates that the model gives an impact-parameter sensitive description of hardron nucleus reactions. (orig.)

  5. The fine particle emissions of energy production in Finland

    International Nuclear Information System (INIS)

    Ohlstroem, M.

    1998-01-01

    The main purpose of this master's thesis was to define the fine particle (PM2.5, diameter under 2,5 μm) emissions of the energy production and to compare the calculated emission factors between different energy production concepts. The purpose was also to define what is known about fine particle emissions and what should still be studied/measured. The purpose was also to compare briefly the fine particle emissions of energy production and vehicle traffic, and their correlations to the fine particle concentrations of urban air. In the theory part of this work a literature survey was made about fine particles in energy production, especially how they form and how they are separated from the flue gas. In addition, the health effects caused by fine particles, and different measuring instruments were presented briefly. In the experimental part of this work, the aim was to find out the fine particle emissions of different energy production processes by calculating specific emission factors (mg/MJ fuel ) from powerplants' annual total particulate matter emissions (t/a), which were obtained from VAHTI-database system maintained by the Finnish Environmental Institute, and by evaluating the share of fine particles from total emissions with the help of existing measurement results. Only those energy production processes which produce significantly direct emissions of solid particles have been treated (pulverised combustion and oil burners from burner combustion, fluidized bed combustion processes, grate boilers, recovery boilers and diesel engines). The processes have been classified according to boiler type, size category, main fuel and also according to dust separation devices. To be able to compare different energy production processes, shared specific emission factor have been calculated for the similar subprocesses. The fine particle emissions depend strongest on the boiler size category and dust separation devices used. Spent fuel or combustion technique does not have

  6. Direct neutrino production and charmed particles

    International Nuclear Information System (INIS)

    Pontecorvo, B.

    1975-01-01

    It is shown that it is feasible to detect electron neutrinos emitted by charmed particles in neutrino experiments characterized by the absence of the pion and kaon decay region. The absolute intensity of the effect looked for in such experiments is small but the background is not large

  7. Chataika Halo.pmd

    African Journals Online (AJOL)

    Prof. Adipala Ekwamu

    INHERITANCE OF HALO BLIGHT RESISTANCE IN COMMON BEAN ... pv phaseolicola (Psp) is a serious seed-borne disease of common bean ... a toxin produced by the Psp bacterium when ... stakes or in association with maize for support.

  8. Calcination of kaolinite clay particles for cement production

    DEFF Research Database (Denmark)

    Gebremariam, Abraham Teklay; Yin, Chungen; Rosendahl, Lasse

    2014-01-01

    Kaolinite rich clay particles calcined under certain conditions can attain favorable pozzolanic properties and can be used to substitute part of the CO2 intensive clinker in cement production. To better guide calcination of a clay material, a transient one-dimensional single particle model...

  9. Hadron and photon production of J particles and the origin of J particles

    International Nuclear Information System (INIS)

    Ting, S.C.C.

    1975-01-01

    Discovery of the J particles (psi-3105 and psi-3695) is detailed. A few experiments on the production of J particles are described, emphasizing photoproduction of J's by photons and hadrons. Finally, current theoretical attempts at explaining their origin are outlined. (29 figures) (U.S.)

  10. Renormalization and operator product expansion in theories with massless particles

    International Nuclear Information System (INIS)

    Anikin, S.A.; Smirnov, V.A.

    1985-01-01

    Renormalization procedure in theories including massless particles is presented. With the help of counterterm formalism the operator product expansion for arbitrary composite fields is derived. The coefficient functions are explicitly expressed in terms of certain Green's functions. (author)

  11. UHE particle production in close binary systems

    International Nuclear Information System (INIS)

    Hillas, A.M.

    1985-01-01

    Cygnus X-3 appears to generate so much power in the form of charged particles of up to approx 10 to the 17th power eV that the galaxy may need approx 1 such source on average to maintain its flux of ultra high energy cosmic rays. Accreting gas must supply the energy, and in a surprisingly ordered form, if it is correct to use a Vest-rand-Eichler model for radiation of gammas, modified by the introduction of an accretion wake. Certain relationships between 10 to the 12th power eV and 10 to the 15th power gamma rays are expected

  12. Cold dark matter. 1: The formation of dark halos

    Science.gov (United States)

    Gelb, James M.; Bertschinger, Edmund

    1994-01-01

    We use numerical simulations of critically closed cold dark matter (CDM) models to study the effects of numerical resolution on observable quantities. We study simulations with up to 256(exp 3) particles using the particle-mesh (PM) method and with up to 144(exp 3) particles using the adaptive particle-particle-mesh (P3M) method. Comparisons of galaxy halo distributions are made among the various simulations. We also compare distributions with observations, and we explore methods for identifying halos, including a new algorithm that finds all particles within closed contours of the smoothed density field surrounding a peak. The simulated halos show more substructure than predicted by the Press-Schechter theory. We are able to rule out all omega = 1 CDM models for linear amplitude sigma(sub 8) greater than or approximately = 0.5 because the simulations produce too many massive halos compared with the observations. The simulations also produce too many low-mass halos. The distribution of halos characterized by their circular velocities for the P3M simulations is in reasonable agreement with the observations for 150 km/s less than or = V(sub circ) less than or = 350 km/s.

  13. Investigation of the production of cobalt-60 via particle accelerator

    Directory of Open Access Journals (Sweden)

    Artun Ozan

    2017-01-01

    Full Text Available The production process of cobalt-60 was simulated by a particle accelerator in the energy range of 5 to 100 MeV, particle beam current of 1 mA, and irradiation time of 1 hour to perform yield, activity of reaction, and integral yield for charged particle-induced reactions. Based on nuclear reaction processes, the obtained results in the production process of cobalt-60 were also discussed in detail to determine appropriate target material, optimum energy ranges, and suitable reactions.

  14. The impact of particle production on gravitational baryogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Lima, J.A.S., E-mail: jas.lima@iag.usp.br [Departamento de Astronomia, Universidade de São Paulo, Rua do Matão 1226, 05508-900, São Paulo (Brazil); Singleton, D., E-mail: dougs@csufresno.edu [Department of Physics, California State University Fresno, Fresno, CA 93740-8031 (United States); ICTP South American Institute for Fundamental Research, UNESP – Univ. Estadual Paulista, Rua Dr. Bento T. Ferraz 271, 01140-070, São Paulo, SP (Brazil); Institute of Experimental and Theoretical Physics Al-Farabi KazNU, Almaty, 050040 (Kazakhstan)

    2016-11-10

    Baryogenesis driven by curvature effects is investigated by taking into account gravitationally induced particle production in the very early Universe. In our scenario, the baryon asymmetry is generated dynamically during an inflationary epoch powered by ultra-relativistic particles. The adiabatic particle production rate provides both the needed negative pressure to accelerate the radiation dominated Universe and a non-zero chemical potential which distinguishes baryons and anti-baryons thereby producing a baryon asymmetry in agreement with the observed value. Reciprocally, the present day asymmetry may be used to determine the inflationary scale at early times. Successful gravitational baryogenesis is dynamically generated for many different choices of the relevant model parameters.

  15. The crystallization processes in the aluminum particles production technology

    Directory of Open Access Journals (Sweden)

    Arkhipov Vladimir

    2015-01-01

    Full Text Available The physical and mathematical model of the crystallization process of liquid aluminum particles in the spray-jet of the ejection-type atomizer was proposed. The results of mathematical modeling of two-phase flow in the spray-jet and the crystallization process of fluid particles are given. The influence of the particle size, of the flow rate and the stagnation temperature gas in the ranges of industrial technology implemented for the production of powders aluminum of brands ASD, on the crystallization characteristics were investigated. The approximations of the characteristics of the crystallization process depending on the size of the aluminum particles on the basis of two approaches to the mathematical description of the process of crystallization of aluminum particles were obtained. The results allow to optimize the process parameters of ejection-type atomizer to produce aluminum particles with given morphology.

  16. Particle production and survival in muon acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Noble, R.J.

    1992-06-01

    Because of the relative immunity of muons to synchrotron radiation, the idea of using them instead of electrons as probes in high-energy physics experiments has existed for some time, but applications were limited by the short muon lifetime. The production and survival of an adequate supply of low-emittance muons will determine the available luminosity in a high-energy physics collider. In this paper the production of pions by protons, their decay to muons and the survival of muons during acceleration are studied. Based on a combination of the various efficiencies, the number of protons needed at the pion source for every muon required in the final high-energy collider is estimated.

  17. Backward particle production in neutrino neon interactions

    International Nuclear Information System (INIS)

    Matsinos, E.; Simopoulou, E.; Giannakopoulos, N.; Vayaki, A.; Guy, J.; Venus, W.; Allport, P.; Cooper-Sarkar, A.M.; Sansum, R.A.; Berggren, M.; Morrison, D.R.O.; Parker, M.A.; Wachsmuth, H.; Calicchio, M.; Erriquez, O.; Coghen, T.; Jones, G.T.; O'Neale, S.O.; Varvell, K.; Marage, P.; Sacton, J.; Mobayyen, M.M.; Schmitz, N.; Wittek, W.; Apeldoorn, G.W. van

    1989-01-01

    Backward proton and pion production is studied in ν and anti ν charged current interactions in neon. The results are compared with other experiments and theory. The complete backward proton data are compatible with protons produced by reinteractions in the nucleus. However in events with only one proton, muon variables appear correlated to those for the backward proton, as expected by the two-nucleon correlation model. (orig.)

  18. Halos and related structures

    DEFF Research Database (Denmark)

    Riisager, Karsten

    2013-01-01

    The halo structure originated from nuclear physics but is now encountered more widely. It appears in loosely bound, clustered systems where the spatial extension of the system is significantly larger than that of the binding potentials. A review is given on our current understanding of these stru......The halo structure originated from nuclear physics but is now encountered more widely. It appears in loosely bound, clustered systems where the spatial extension of the system is significantly larger than that of the binding potentials. A review is given on our current understanding...... of these structures, with an emphasis on how the structures evolve as more cluster components are added and on the experimental situation concerning halo states in light nuclei....

  19. Production of heavy particles by protons on protons

    International Nuclear Information System (INIS)

    Afek, Y.; Margolis, B.; Polvani, L.

    1982-01-01

    We calculate the production of heavy particles in the multi-GeV energy range using parton-model and statistical considerations. We discuss both central production and fragmentation. Our picture has implications for the question of the existence of a limiting temperature in hardron interaction

  20. Production of metal particles and clusters

    Science.gov (United States)

    Mcmanus, S. P.

    1982-01-01

    The feasibility of producing novel metals or metal clusters in a low gravity environment was studied. The production of coordinately unsaturated metal carbonyls by thermolysis or photolysis of stable metal carbonyls has the potential to generate novel catalysts by this technique. Laser irradiation of available metal carbonyls was investigated. It is found that laser induced decomposition of metal carbonyls is feasible for producing a variety of coordinately unsaturated species. Formation of clustered species does occur but is hampered by weak metal-metal bonds.

  1. Weighing halo nuclides

    International Nuclear Information System (INIS)

    Lunney, D.

    2009-01-01

    Weak binding energy is one of the fundamental criteria characterizing the unique properties of nuclear halos. As such, it must be known with great accuracy and is best obtained through direct mass measurements. The global mass market is now a competitive one. Of the many investment vehicles, the Penning trap has emerged as providing the best rate of return and reliability. We examine mass-market trends, highlighting the recent cases of interest. We also hazard a prediction for the halo futures market. (author)

  2. The role of Dark Matter sub-halos in the non-thermal emission of galaxy clusters

    Energy Technology Data Exchange (ETDEWEB)

    Marchegiani, Paolo; Colafrancesco, Sergio, E-mail: Paolo.Marchegiani@wits.ac.za, E-mail: Sergio.Colafrancesco@wits.ac.za [School of Physics, University of the Witwatersrand, Private Bag 3, WITS-2050, Johannesburg (South Africa)

    2016-11-01

    Annihilation of Dark Matter (DM) particles has been recognized as one of the possible mechanisms for the production of non-thermal particles and radiation in galaxy clusters. Previous studies have shown that, while DM models can reproduce the spectral properties of the radio halo in the Coma cluster, they fail in reproducing the shape of the radio halo surface brightness because they produce a shape that is too concentrated towards the center of the cluster with respect to the observed one. However, in previous studies the DM distribution was modeled as a single spherically symmetric halo, while the DM distribution in Coma is found to have a complex and elongated shape. In this work we calculate a range of non-thermal emissions in the Coma cluster by using the observed distribution of DM sub-halos. We find that, by including the observed sub-halos in the DM model, we obtain a radio surface brightness with a shape similar to the observed one, and that the sub-halos boost the radio emission by a factor between 5 and 20%, thus allowing to reduce the gap between the annihilation cross section required to reproduce the radio halo flux and the upper limits derived from other observations, and that this gap can be explained by realistic values of the boosting factor due to smaller substructures. Models with neutralino mass of 9 GeV and composition τ{sup +} τ{sup −}, and mass of 43 GeV and composition b b-bar can fit the radio halo spectrum using the observed properties of the magnetic field in Coma, and do not predict a gamma-ray emission in excess compared to the recent Fermi-LAT upper limits. These findings make these DM models viable candidate to explain the origin of radio halos in galaxy clusters, avoiding the problems connected to the excessive gamma-ray emission expected from proton acceleration in most of the currently proposed models, where the acceleration of particles is directly or indirectly connected to events related to clusters merging. Therefore, DM

  3. MEASUREMENT AND SIMULATION OF SOURCE-GENERATED HALOS IN THE UNIVERSITY OF MARYLAND ELECTRON RING (UMER)

    International Nuclear Information System (INIS)

    Haber, I.; Haber, I.; Bernal, S.; Kishek, R.A.; O'Shea, P.G.; Papadopoulos, C.; Reiser, M.; Feldman, R.B.; Stratakis, D.; Walter, M.; Vay, J.-L.; Friedman, A.; Grote, D.P.

    2007-01-01

    One of the areas of fundamental beam physics that have served as the rationale for recent research on UMER is the study of the generation and evolution of beam halos. Recent experiments and simulations have identified imperfections in the source geometry, particularly in the region near the emitter edge, as a significant potential source of halo particles. The edge-generated halo particles, both in the experiments and the simulations are found to pass through the center of the beam a short distance downstream of the anode plane. Understanding the detailed evolution of these particle orbits is therefore important to designing any aperture to remove the beam halo

  4. Universal behavior of charged particle production in heavy ion collisions

    Science.gov (United States)

    Phobos Collaboration; Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at sqrt(s_NN) = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/pbar-p and e+e- data. N_tot/(N_part/2) in nuclear collisions at high energy scales with sqrt(s) in a similar way as N_tot in e+e- collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  5. Hazardous Gas Production by Alpha Particles

    International Nuclear Information System (INIS)

    LaVerne, Jay A.

    2001-01-01

    This project focused on the production of hazardous gases in the radiolysis of solid organic matrices, such as polymers and resins, that may be associated with transuranic waste material. Self-radiolysis of radioactive waste is a serious environmental problem because it can lead to a change in the composition of the materials in storage containers and possibly jeopardize their integrity. Experimental determination of gaseous yields is of immediate practical importance in the engineering and maintenance of containers for waste materials. Fundamental knowledge on the radiation chemical processes occurring in these systems allows one to predict outcomes in materials or mixtures not specifically examined, which is a great aid in the management of the variety of waste materials currently overseen by Environmental Management

  6. Hidden particle production at the ILC

    International Nuclear Information System (INIS)

    Fujii, Keisuke; Itoh, Hideo; Okada, Nobuchika; Hano, Hitoshi; Yoshioka, Tamaki

    2008-01-01

    In a class of new physics models, the new physics sector is completely or partly hidden, namely, a singlet under the standard model (SM) gauge group. Hidden fields included in such new physics models communicate with the standard model sector through higher-dimensional operators. If a cutoff lies in the TeV range, such hidden fields can be produced at future colliders. We consider a scalar field as an example of the hidden fields. Collider phenomenology on this hidden scalar is similar to that of the SM Higgs boson, but there are several features quite different from those of the Higgs boson. We investigate productions of the hidden scalar at the International Linear Collider (ILC) and study the feasibility of its measurements, in particular, how well the ILC distinguishes the scalar from the Higgs boson, through realistic Monte Carlo simulations.

  7. Particle size distribution of selected electronic nicotine delivery system products.

    Science.gov (United States)

    Oldham, Michael J; Zhang, Jingjie; Rusyniak, Mark J; Kane, David B; Gardner, William P

    2018-03-01

    Dosimetry models can be used to predict the dose of inhaled material, but they require several parameters including particle size distribution. The reported particle size distributions for aerosols from electronic nicotine delivery system (ENDS) products vary widely and don't always identify a specific product. A low-flow cascade impactor was used to determine the particle size distribution [mass median aerodynamic diameter (MMAD); geometric standard deviation (GSD)] from 20 different cartridge based ENDS products. To assess losses and vapor phase amount, collection efficiency of the system was measured by comparing the collected mass in the impactor to the difference in ENDS product mass. The levels of nicotine, glycerin, propylene glycol, water, and menthol in the formulations of each product were also measured. Regardless of the ENDS product formulation, the MMAD of all tested products was similar and ranged from 0.9 to 1.2 μm with a GSD ranging from 1.7 to 2.2. There was no consistent pattern of change in the MMAD and GSD as a function of number of puffs (cartridge life). The collection efficiency indicated that 9%-26% of the generated mass was deposited in the collection system or was in the vapor phase. The particle size distribution data are suitable for use in aerosol dosimetry programs. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Validity of the negative binomial distribution in particle production

    International Nuclear Information System (INIS)

    Cugnon, J.; Harouna, O.

    1987-01-01

    Some aspects of the clan picture for particle production in nuclear and in high-energy processes are examined. In particular, it is shown that the requirement of having logarithmic distribution for the number of particles within a clan in order to generate a negative binomial should not be taken strictly. Large departures are allowed without distorting too much the negative binomial. The question of the undetected particles is also studied. It is shown that, under reasonable circumstances, the latter do not affect the negative binomial character of the multiplicity distribution

  9. Subthreshold particle production in heavy-ion collisions

    International Nuclear Information System (INIS)

    Mosel, U.

    1991-01-01

    Subthreshold production processes are discussed in the theoretical framework, checking data obtained from hard-photon production in the energy range from 20 to 100 MeV/u. The reactions at higher energies are described and the predictions for particle production cross sections are discussed. A particular attention to properties of hadrons (nucleons and mesons) in the nuclear medium is given. (M.C.K.)

  10. Strange Particle Production from SIS to LHC

    CERN Document Server

    Oeschler, H; Redlich, Krzysztof

    2003-01-01

    A review of meson emission in heavy ion collisions at incident energies from SIS up to collider energies is presented. A statistical model assuming chemical equilibrium and local strangeness conservation (i.e. strangeness conservation per collision) explains most of the observed features. Emphasis is put onto the study of $K^+$ and $K^-$ emission at low incident energies. In the framework of this statistical model it is shown that the experimentally observed equality of $K^+$ and $K^-$ rates at ``threshold-corrected'' energies $\\sqrt{s} - \\sqrt{s_{th}}$ is due to a crossing of two excitation functions. Furthermore, the independence of the $K^+$ to $K^-$ ratio on the number of participating nucleons observed between SIS and RHIC is consistent with this model. It is demonstrated that the $K^-$ production at SIS energies occurs predominantly via strangeness exchange and this channel is approaching chemical equilibrium. The observed maximum in the $K^+/\\pi^+$ excitation function is also seen in the ratio of stran...

  11. Particle Production under External Fields and Its Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States)

    2014-01-01

    The thesis presents studies of vacuum pair productions and its applications in early universe cosmology and high energy astrophysics. Vacuum often becomes unstable and spontaneously decays into pairs of particles in rapidly expanding universes or under strong external electromagnetic fields. Theoretically, spontaneous pair productions due to such non-trivial backgrounds of spacetimes or electromagnetic fields are well-understood. However, the effect of particle productions has not been observed so far because of experiemtal difficulties in obtaining large curvatures of space-times or strong electric fields. Although it may be impossible to observe the pair productions directly via laboratory experiments, there are still powerful sources of space-time curvatures or electric fields in cosmology and astrophysics, which result in observations. In Part I, we explore the inflationary models in early universe utilizing pair productions through gravity. We study observable signatures on the cosmic microwave background, such as isocurvature perturbations and non-Gaussianities, generated from the particle production of WIMPzillas and axions during or after inflation. In Part II, we investigate the electron-positron pair production in the magnetosphere of pulsars whose electromagnetic fields are expected to close to or even greater than the pair production threshold. In particular, we demonstrate that the pair production may be responsible for giant pulses from the Crab pulsar.

  12. Fission product released experiment of coated fuel particles

    Energy Technology Data Exchange (ETDEWEB)

    Shijiang, Xu; Bing, Yang; Chunhe, Tang; Junguo, Zhu; Jintao, Huang; Binzhong, Zhang [Inst. of Nucl. Energy Technology, Tsinghua Univ., Beijing (China); Jinghan, Luo [Inst. of Atomic Energy, Beijing (China)

    1992-01-15

    Four samples of coated fuel particles were irradiated in the Heavy-Water Research Reactor of the Institute of Atomic Energy. Each of them was divided into two groups and irradiated to the burn up of 0.394% fima and 0.788% fima in two static capsules, respectively. After irradiation and cooling, post irradiation annealing experiment was carried out, the release ratios of the fission product {sup 133}Xe and {sup 131}I were measured, they are in the order of 10{sup -6}{approx}10{sup -7}. The fission product release ratio of naked kernel was also measured under the same conditions as for the coated fuel particles, the ratio of the fission product release of the coated fuel particles and of the naked kernel was in the order of 10{sup -5}{approx}10{sup -4}.

  13. Spectrum of Sprite Halos

    Czech Academy of Sciences Publication Activity Database

    Gordillo-Vázquez, F.J.; Luque, A.; Šimek, Milan

    2011-01-01

    Roč. 116, č. 9 (2011), A09319-A09319 ISSN 0148-0227 Institutional research plan: CEZ:AV0Z20430508 Keywords : sprites * halos * spectroscopy Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.021, year: 2011 http://www.trappa.iaa.es/sites/all/files/papers/isi_journal_papers/2011/2011_08.pdf

  14. Isolation and characterization of biosurfactant production under extreme environmental conditions by alkali-halo-thermophilic bacteria from Saudi Arabia.

    Science.gov (United States)

    Elazzazy, Ahmed M; Abdelmoneim, T S; Almaghrabi, O A

    2015-07-01

    Twenty three morphologically distinct microbial colonies were isolated from soil and sea water samples, which were collected from Jeddah region, Saudi Arabia for screening of the most potent biosurfactant strains. The isolated bacteria were selected by using different methods as drop collapse test, oil displacement test, blue agar test, blood hemolysis test, emulsification activity and surface tension. The results showed that the ability of Virgibacillus salarius to grow and reduce surface tension under a wide range of pH, salinities and temperatures gives bacteria isolate an advantage in many applications such as pharmaceutical, cosmetics, food industries and bioremediation in marine environment. The biosurfactant production by V. salarius decreased surface tension and emulsifying activity (30 mN/m and 80%, respectively). In addition to reducing the production cost of biosurfactants by tested several plant-derived oils such as jatropha oil, castor oils, jojoba oil, canola oil and cottonseed oil. In this respect the feasibility to reusing old frying oil of sunflower for production rhamnolipids and sophorolipids, their use that lead to solve many ecological and industrial problems.

  15. Isolation and characterization of biosurfactant production under extreme environmental conditions by alkali-halo-thermophilic bacteria from Saudi Arabia

    Science.gov (United States)

    Elazzazy, Ahmed M.; Abdelmoneim, T.S.; Almaghrabi, O.A.

    2014-01-01

    Twenty three morphologically distinct microbial colonies were isolated from soil and sea water samples, which were collected from Jeddah region, Saudi Arabia for screening of the most potent biosurfactant strains. The isolated bacteria were selected by using different methods as drop collapse test, oil displacement test, blue agar test, blood hemolysis test, emulsification activity and surface tension. The results showed that the ability of Virgibacillus salarius to grow and reduce surface tension under a wide range of pH, salinities and temperatures gives bacteria isolate an advantage in many applications such as pharmaceutical, cosmetics, food industries and bioremediation in marine environment. The biosurfactant production by V. salarius decreased surface tension and emulsifying activity (30 mN/m and 80%, respectively). In addition to reducing the production cost of biosurfactants by tested several plant-derived oils such as jatropha oil, castor oils, jojoba oil, canola oil and cottonseed oil. In this respect the feasibility to reusing old frying oil of sunflower for production rhamnolipids and sophorolipids, their use that lead to solve many ecological and industrial problems. PMID:26150754

  16. Biasing secondary particle interaction physics and production in MCNP6

    International Nuclear Information System (INIS)

    Fensin, M.L.; James, M.R.

    2016-01-01

    Highlights: • Biasing secondary production and interactions of charged particles in the tabular energy regime. • Examining lower weight window bounds for rare events when using Russian roulette. • The new biasing strategy can speedup calculations by a factor of 1 million or more. - Abstract: Though MCNP6 will transport elementary charged particles and light ions to low energies (i.e. less than 20 MeV), MCNP6 has historically relied on model physics with suggested minimum energies of ∼20 to 200 MeV. Use of library data for the low energy regime was developed for MCNP6 1.1.Beta to read and use light ion libraries. Thick target yields of neutron production for alphas on fluoride result in 1 production event per roughly million sampled alphas depending on the energy of the alpha (for other isotopes the yield can be even rarer). Calculation times to achieve statistically significant and converged thick target yields are quite laborious, needing over one hundred processor hours. The MUCEND code possess a biasing technique for improving the sampling of secondary particle production by forcing a nuclear interaction to occur per each alpha transported. We present here a different biasing strategy for secondary particle production from charged particles. During each substep, as the charged particle slows down, we bias both a nuclear collision event to occur at each substep and the production of secondary particles at the collision event, while still continuing to progress the charged particle until reaching a region of zero importance or an energy/time cutoff. This biasing strategy is capable of speeding up calculations by a factor of a million or more as compared to the unbiased calculation. Further presented here are both proof that the biasing strategy is capable of producing the same results as the unbiased calculation and the limitations to consider in order to achieve accurate results of secondary particle production. Though this strategy was developed for MCNP

  17. Production of particles by a variable scalar field

    International Nuclear Information System (INIS)

    Dolgov, A.D.; Kirilova, D.P.

    1990-01-01

    The probability of particle production by a spatially homogeneous scalar field χ(t) is calculated. Explicit analytic expressions are obtained in two opposite limiting cases: in perturbation theory and in the quasiclassical approximation. It is shown that if the mass of the produced particles is determined by the field χ(t) is accordance with the expression gχ(t) anti ψψ, then for an oscillatory field χ(t) = χ 0 cos(ωt) the production probability in the limit of small ω is suppressed not exponentially, but only as ω 1/2 . Cosmological applications of these results are discussed

  18. SEEDING THE FORMATION OF COLD GASEOUS CLOUDS IN MILKY WAY-SIZE HALOS

    International Nuclear Information System (INIS)

    Keres, Dusan; Hernquist, Lars

    2009-01-01

    We use one of the highest resolution cosmological smoothed particle hydrodynamic simulations to date to demonstrate that cold gaseous clouds form around Milky Way-size galaxies. We further explore mechanisms responsible for their formation and show that a large fraction of clouds originate as a consequence of late-time filamentary 'cold mode' accretion. Here, filaments that are still colder and denser than the surrounding halo gas are not able to connect directly to galaxies, as they do at high redshift, but are instead susceptible to the combined action of cooling and Rayleigh-Taylor instabilities at intermediate radii within the halo leading to the production of cold, dense pressure-confined clouds, without an associated dark matter component. This process is aided through the compression of the incoming filaments by the hot halo gas and expanding shocks during the halo buildup. Our mechanism directly seeds clouds from gas with substantial local overdensity, unlike in previous models, and provides a channel for the origin of cloud complexes. These clouds can later 'rain' onto galaxies, delivering fuel for star formation. Owing to the relatively large cross-section of filaments and the net angular momentum carried by the gas, the clouds will be distributed in a modestly flattened region around a galaxy.

  19. Structure study in the 19C halo

    International Nuclear Information System (INIS)

    Angelique, J.C.; Le Brun, C.; Liegard, E.; Marques, F.M.; Orr, N.A.

    1997-01-01

    The halo nuclei are nuclei which have one or more neutrons (or protons) with very weak binding energy what results in a spatial extension beyond the core containing the other nucleons. This important spatial extension is related via the Heisenberg principle to a narrow momentum distribution which signs the halo structure of the nucleus under consideration. To extend our understanding of this phenomenon an experiment has been carried out with the DEMON multidetector in the frame of the collaboration E133. The subject was the study of 19 C, a nucleus susceptible of having a neutron halo due to the low binding energy of its last neutron (S n = 240 ± 100 keV). The 19 C secondary beam was produced by fragmentation of a primary 40 Ar beam in a carbon target between the two solenoids of SISSI and than directed to a GANIL experimental room. A silicon detector telescope was used to detect the charged particles issued from the reaction of 19 C nuclei with the tantalum target while the DEMON detection modular assembly separated by four meters from the target allowed the neutron detection between 0 and 42 degrees. The first results of this analysis are favorable to a halo structure for this nucleus for the reaction channel in which the 18 C core is destroyed. We have compared the angular distribution of the neutrons of 19 C with those obtained from the breakup reactions of other exotic nuclei ( 21 N, 22 O and 24 F) but having no halo structure. A net different behavior of these nuclei indicate a clear difference in structure. Actually, the 19 C distribution corresponds to the superposition of a broad distribution and narrow distribution. The last one having width of 42 ± 12 MeV/c, compatible with an important spatial extension, corresponds to neutrons coming from the halo. It is argued that the model in which the halo neutron moves on a s orbital cannot described the structure of 19 C halo. A more adequate description would be a mixture of s and d orbitals which would also

  20. Neutral strange particle production in neutrino interactions at Tevatron energies

    International Nuclear Information System (INIS)

    De, K.

    1988-05-01

    This thesis reports on a study of neutral strange particle production by high energy muon-neutrinos. The neutrinos were obtained from a 800 GeV proton beam-dump at Fermilab. Neutrino events were observed using a hybrid bubble chamber detector system. The data contained deep inelastic neutrino-nucleon interactions with an average momentum transfer 2 > = 23 (GeV/c) 2 . Rates for K 0 and Λ production in neutrino and anti-neutrino charged current events are presented. The distributions of these particles in Feynman x and rapidity are also studied. Significant differences were observed in the production mechanism for the K 0 meson and the Λ baryon. The production rates of K 0 's were observed to increase with energy, whereas the rates for Λ production remained essentially constant. In Feynman x, the K 0 's were produced in the central region and the Λ's were produced backwards. The data are compared with the LUND monte carlo for string fragmentation. In the monte carlo, K 0 's are mostly produced from s/bar s/ pair production during fragmentation. The Λ's are generally produced through recombination with the diquark from the target nucleon. The data agree with this model for strange particle production. 39 refs., 24 figs., 10 tabs

  1. MD 1691: Active halo control using tune ripple at injection

    CERN Document Server

    Garcia Morales, Hector; Bruce, Roderik; Redaelli, Stefano; Fitterer, Miriam; Fiascaris, Maria; Nisbet, David; Thiesen, Hugues; Valentino, Gianluca; Xu, Chen; CERN. Geneva. ATS Department

    2017-01-01

    In this MD we performed halo excitation through tune ripple. This consists in an excitation that introduces new resonance sidebands around the existing resonance lines. In presence of sufficient detuning with amplitude, these sidebands can in principle affect only the dynamics of the halo particles at large amplitudes. Tune ripple was induced through a current modulation of the warm trim quadrupoles in IR7. This is the first time this method is experimentally tested at the LHC.

  2. Testing approximate predictions of displacements of cosmological dark matter halos

    Energy Technology Data Exchange (ETDEWEB)

    Munari, Emiliano; Monaco, Pierluigi; Borgani, Stefano [Department of Physics, Astronomy Unit, University of Trieste, via Tiepolo 11, I-34143 Trieste (Italy); Koda, Jun [INAF – Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy); Kitaura, Francisco-Shu [Instituto de Astrofísica de Canarias, 38205 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Sefusatti, Emiliano, E-mail: munari@oats.inaf.it, E-mail: monaco@oats.inaf.it, E-mail: jun.koda@brera.inaf.it, E-mail: fkitaura@iac.es, E-mail: sefusatti@oats.inaf.it, E-mail: borgani@oats.inaf.it [INAF – Osservatorio Astronomico di Trieste, via Tiepolo 11, I-34143 Trieste (Italy)

    2017-07-01

    We present a test to quantify how well some approximate methods, designed to reproduce the mildly non-linear evolution of perturbations, are able to reproduce the clustering of DM halos once the grouping of particles into halos is defined and kept fixed. The following methods have been considered: Lagrangian Perturbation Theory (LPT) up to third order, Truncated LPT, Augmented LPT, MUSCLE and COLA. The test runs as follows: halos are defined by applying a friends-of-friends (FoF) halo finder to the output of an N-body simulation. The approximate methods are then applied to the same initial conditions of the simulation, producing for all particles displacements from their starting position and velocities. The position and velocity of each halo are computed by averaging over the particles that belong to that halo, according to the FoF halo finder. This procedure allows us to perform a well-posed test of how clustering of the matter density and halo density fields are recovered, without asking to the approximate method an accurate reconstruction of halos. We have considered the results at z =0,0.5,1, and we have analysed power spectrum in real and redshift space, object-by-object difference in position and velocity, density Probability Distribution Function (PDF) and its moments, phase difference of Fourier modes. We find that higher LPT orders are generally able to better reproduce the clustering of halos, while little or no improvement is found for the matter density field when going to 2LPT and 3LPT. Augmentation provides some improvement when coupled with 2LPT, while its effect is limited when coupled with 3LPT. Little improvement is brought by MUSCLE with respect to Augmentation. The more expensive particle-mesh code COLA outperforms all LPT methods, and this is true even for mesh sizes as large as the inter-particle distance. This test sets an upper limit on the ability of these methods to reproduce the clustering of halos, for the cases when these objects are

  3. Testing approximate predictions of displacements of cosmological dark matter halos

    Science.gov (United States)

    Munari, Emiliano; Monaco, Pierluigi; Koda, Jun; Kitaura, Francisco-Shu; Sefusatti, Emiliano; Borgani, Stefano

    2017-07-01

    We present a test to quantify how well some approximate methods, designed to reproduce the mildly non-linear evolution of perturbations, are able to reproduce the clustering of DM halos once the grouping of particles into halos is defined and kept fixed. The following methods have been considered: Lagrangian Perturbation Theory (LPT) up to third order, Truncated LPT, Augmented LPT, MUSCLE and COLA. The test runs as follows: halos are defined by applying a friends-of-friends (FoF) halo finder to the output of an N-body simulation. The approximate methods are then applied to the same initial conditions of the simulation, producing for all particles displacements from their starting position and velocities. The position and velocity of each halo are computed by averaging over the particles that belong to that halo, according to the FoF halo finder. This procedure allows us to perform a well-posed test of how clustering of the matter density and halo density fields are recovered, without asking to the approximate method an accurate reconstruction of halos. We have considered the results at z=0,0.5,1, and we have analysed power spectrum in real and redshift space, object-by-object difference in position and velocity, density Probability Distribution Function (PDF) and its moments, phase difference of Fourier modes. We find that higher LPT orders are generally able to better reproduce the clustering of halos, while little or no improvement is found for the matter density field when going to 2LPT and 3LPT. Augmentation provides some improvement when coupled with 2LPT, while its effect is limited when coupled with 3LPT. Little improvement is brought by MUSCLE with respect to Augmentation. The more expensive particle-mesh code COLA outperforms all LPT methods, and this is true even for mesh sizes as large as the inter-particle distance. This test sets an upper limit on the ability of these methods to reproduce the clustering of halos, for the cases when these objects are

  4. On thermal gravitational contribution to particle production and dark matter

    Directory of Open Access Journals (Sweden)

    Yong Tang

    2017-11-01

    Full Text Available We investigate the particle production from thermal gravitational annihilation in the very early universe, which is an important contribution for particles that might not be in thermal equilibrium or/and might only have gravitational interaction, such as dark matter (DM. For particles with spin 0,1/2 and 1 we calculate the relevant cross sections through gravitational annihilation and give the analytic formulas with full mass-dependent terms. We find that DM with mass between TeV and 1016 GeV could have the relic abundance that fits the observation, with small dependence on its spin. We also discuss the effects of gravitational annihilation from inflatons. Interestingly, contributions from inflatons could be dominant and have the same power dependence on Hubble parameter of inflation as that from vacuum fluctuation. Also, fermion production from inflaton, in comparison to boson, is suppressed by its mass due to helicity selection.

  5. Resonant particle production during inflation: a full analytical study

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Lauren; Peloso, Marco [School of Physics and Astronomy, University of Minnesota, 116 Church Street S.E., Minneapolis, MN 55455 (United States); Sorbo, Lorenzo, E-mail: lpearce@physics.umn.edu, E-mail: peloso@physics.umn.edu, E-mail: sorbo@physics.umass.edu [Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts, 1126 Lederle Graduate Research Tower (LGRT), Amherst, MA 01003 (United States)

    2017-05-01

    We revisit the study of the phenomenology associated to a burst of particle production of a field whose mass is controlled by the inflaton field and vanishes at one given instance during inflation. This generates a bump in the correlators of the primordial scalar curvature. We provide a unified formalism to compute various effects that have been obtained in the literature and confirm that the dominant effects are due to the rescattering of the produced particles on the inflaton condensate. We improve over existing results (based on numerical fits) by providing exact analytic expressions for the shape and height of the bump, both in the power spectrum and the equilateral bispectrum. We then study the regime of validity of the perturbative computations of this signature. Finally, we extend these computations to the case of a burst of particle production in a sector coupled only gravitationally to the inflaton.

  6. What sets the central structure of dark matter haloes?

    Science.gov (United States)

    Ogiya, Go; Hahn, Oliver

    2018-02-01

    Dark matter (DM) haloes forming near the thermal cut-off scale of the density perturbations are unique, since they are the smallest objects and form through monolithic gravitational collapse, while larger haloes contrastingly have experienced mergers. While standard cold dark matter (CDM) simulations readily produce haloes that follow the universal Navarro-Frenk-White (NFW) density profile with an inner slope, ρ ∝ r-α, with α = 1, recent simulations have found that when the free-streaming cut-off expected for the CDM model is resolved, the resulting haloes follow nearly power-law density profiles of α ∼ 1.5. In this paper, we study the formation of density cusps in haloes using idealized N-body simulations of the collapse of proto-haloes. When the proto-halo profile is initially cored due to particle free-streaming at high redshift, we universally find ∼r-1.5 profiles irrespective of the proto-halo profile slope outside the core and large-scale non-spherical perturbations. Quite in contrast, when the proto-halo has a power-law profile, then we obtain profiles compatible with the NFW shape when the density slope of the proto-halo patch is shallower than a critical value, αini ∼ 0.3, while the final slope can be steeper for αini ≳ 0.3. We further demonstrate that the r-1.5 profiles are sensitive to small-scale noise, which gradually drives them towards an inner slope of -1, where they become resilient to such perturbations. We demonstrate that the r-1.5 solutions are in hydrostatic equilibrium, largely consistent with a simple analytic model, and provide arguments that angular momentum appears to determine the inner slope.

  7. Energy dissipation and charged particle production in heavy ion collisions

    International Nuclear Information System (INIS)

    Mishra, Aditya Nath; Sahoo, Raghunath; Sarkisyan Edward, K.G.; )

    2013-01-01

    In this paper, we use a model combining the constituent quark picture with Landau relativistic hydrodynamics. Within this model, the secondary particle production in nucleus-nucleus or nucleon-nucleon (p-barp/pp) collisions is basically driven by the amount of the initial effective energy deposited by participants (quarks or nucleons) into the Lorentz contracted overlap region

  8. Production of new particles in electron-positron annihilation

    International Nuclear Information System (INIS)

    Gilman, F.J.

    1977-02-01

    A number of areas are reviewed where there is important progress in the production of new particles in electron--positron annihilation, but of a more detailed quantitative nature. Charmonium states, charmed mesons, and evidence for a charged heavy lepton are covered. 50 references

  9. THE OVERDENSITY AND MASSES OF THE FRIENDS-OF-FRIENDS HALOS AND UNIVERSALITY OF HALO MASS FUNCTION

    International Nuclear Information System (INIS)

    More, Surhud; Kravtsov, Andrey V.; Dalal, Neal; Gottloeber, Stefan

    2011-01-01

    The friends-of-friends algorithm (hereafter FOF) is a percolation algorithm which is routinely used to identify dark matter halos from N-body simulations. We use results from percolation theory to show that the boundary of FOF halos does not correspond to a single density threshold but to a range of densities close to a critical value that depends upon the linking length parameter, b. We show that for the commonly used choice of b = 0.2, this critical density is equal to 81.62 times the mean matter density. Consequently, halos identified by the FOF algorithm enclose an average overdensity which depends on their density profile (concentration) and therefore changes with halo mass, contrary to the popular belief that the average overdensity is ∼180. We derive an analytical expression for the overdensity as a function of the linking length parameter b and the concentration of the halo. Results of tests carried out using simulated and actual FOF halos identified in cosmological simulations show excellent agreement with our analytical prediction. We also find that the mass of the halo that the FOF algorithm selects crucially depends upon mass resolution. We find a percolation-theory-motivated formula that is able to accurately correct for the dependence on number of particles for the mock realizations of spherical and triaxial Navarro-Frenk-White halos. However, we show that this correction breaks down when applied to the real cosmological FOF halos due to the presence of substructures. Given that abundance of substructure depends on redshift and cosmology, we expect that the resolution effects due to substructure on the FOF mass and halo mass function will also depend on redshift and cosmology and will be difficult to correct for in general. Finally, we discuss the implications of our results for the universality of the mass function.

  10. Production and propagation of secondary particles near the earth

    International Nuclear Information System (INIS)

    Derome, L.

    2008-01-01

    A few years ago the AMS01 embarked experiment showed a particular high component of the cosmic particle flux detected below the geo-magnetic cut which was surprising because this cut represents the minimal energy that is required for cosmic radiation to reach the earth and any cosmic ray below the cut is pushed away by the earth's magnetic field. This work is based on Monte-Carlo simulations involving the generation of primary cosmic particles, their propagation in the earth magnetic field, their interaction with earth's atmosphere and the production of secondary particles. These simulations have shown that the particles below the cut are in fact particles generated in the upper part of the atmosphere, escaping from it and being trapped by the earth's magnetic field. These Monte-Carlo simulations have also been used to assess the composition of below-the-cut flux in terms of protons, electrons, positrons and light nuclei, to check the production of anti-matter in the atmosphere, and to estimate the flux of atmospheric neutrinos. (A.C.)

  11. Measurement of charmed particle production in hadronic reactions

    CERN Multimedia

    2002-01-01

    The aim of the experiment is to measure the production cross-section for charmed particles in hadronic reactions, study their production mechanism, and search for excited charmed hadrons.\\\\ \\\\ Charmed Mesons and Baryons will be measured in $\\pi$ and $p$ interactions on Beryllium between 100 and 200 GeV/c. The trigger will be on an electron from the leptonic decay of one charmed particle by signals from the Cerenkov counter (Ce), the electron trigger calorimeter (eCal), scintillation counters, and proportional wire chambers. The accompanying charmed particle will be measured via its hadronic decay in a two-stage magnetic spectrometer with drift chambers (arms 2, 3a, 3b, 3c), two large-area multicell Cerenkov counters (C2, C3) and a large-area shower counter ($\\gamma$-CAL). The particles which can be measured and identified include $\\gamma, e, \\pi^{\\pm}, \\pi^{0}, K^{\\pm}, p, \\bar{p}$ so that a large number of hadronic decay modes of charmed particles can be studied. \\\\ \\\\ A silicon counter telescope with 5 $\\m...

  12. Simulation on control of beam halo-chaos by power function in the hackle periodic-focusing channel

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The K-V beam through a hackle periodic-focusing magnetic field is studied using the particle-core model. The beam halo-chaos is found, and a power function controller is proposed based on mechanism of halo formation and strategy of controlling halo-chaos. Multiparticle simulation was performed to control the halo by using the power function control method. The results show that the halo-chaos and its regeneration can be eliminated effectively. We also find that the radial particle density evolvement is of uniformity at the beam's centre as long as appropriate paramours are chosen.

  13. Primordial black holes formation from particle production during inflation

    International Nuclear Information System (INIS)

    Erfani, Encieh

    2016-01-01

    We study the possibility that particle production during inflation can source the required power spectrum for dark matter (DM) primordial black holes (PBH) formation. We consider the scalar and the gauge quanta production in inflation models, where in the latter case, we focus in two sectors: inflaton coupled i) directly and ii) gravitationally to a U(1) gauge field. We do not assume any specific potential for the inflaton field. Hence, in the gauge production case, in a model independent way we show that the non-production of DM PBHs puts stronger upper bound on the particle production parameter. Our analysis show that this bound is more stringent than the bounds from the bispectrum and the tensor-to-scalar ratio derived by gauge production in these models. In the scenario where the inflaton field coupled to a scalar field, we put an upper bound on the amplitude of the generated scalar power spectrum by non-production of PBHs. As a by-product we also show that the required scalar power spectrum for PBHs formation is lower when the density perturbations are non-Gaussian in comparison to the Gaussian density perturbations

  14. Particle production in hot and dense nuclear matter

    International Nuclear Information System (INIS)

    Eklund, A.

    1992-08-01

    The charged particle production in heavy ion reactions at 200 A GeV has been studied for projectiles of 16 O and 32 S on targets of Al, Cu, Ag and Au. Up to 700 charged particles are measured in the pseudorapidity region -1.7 32 S+Au. The measured particle density is used to estimate the energy density attained in central collisions and gives a values of ≅2 GeV/fm 3 . This is close to the energy density predicted for the phase transition from hadronic matter to a quark-gluon plasma. To measure the large number of charged particle produced, finely granulated detector systems are employed. Streamer tube detectors with pad readout and large area, multi-step avalanche chambers with optical readout have been developed for the measurements. The widths of the pseudorapidity distributions of charged particles increase with decreasing centrality of the collision as well as with increasing mass of the target nucleus. This behaviour is assumed to be due to the target fragmentation. The Monte-Carlo model for nucleus-nucleus collisions, VENUS 3.11, which includes rescattering, is in reasonable agreement with the data. The yield of charged particles for central collisions of the heavy targets with 33 S is found to be proportional to the target mass, A, at target rapidity. At midrapidity it is approximately proportional to A 0.3 . At midrapidity the charged particle measurements are supplemented by measurements of the transverse energy. The dimensionless, normalized variances of the multiplicity and transverse energy distributions are, to a large extent, governed by the collision geometry. The change in the normalized variance when studying the charged particle distribution in a narrow angular region is explained as being of statistical nature. (au)

  15. Particle production in high energy nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Stock, R.

    1985-05-01

    Recent data on the production of pions and strange particles at the Bevalac and Synchrophasotron accelerators are reviewed, covering pion spectra and multiplicity distributions, Λ, K + and K - yields and spectra, and Λ polarization. Emphasis is placed on recent progress in determining the equation of state of compressed fireball nuclear matter from the observed pion yield in central collisions. Further, the information derived from apparent spectral temperatures is critically examined, along with a discussion of thermal and chemical equilibrium attainment in the reactions, as revealed by particle spectra and yields. (orig.)

  16. Intrinsic charm and charmed particle production at Serpukhov energies

    International Nuclear Information System (INIS)

    Zmushko, V.V.

    1995-01-01

    This paper presents a study of the charmed particle production by protons on nuclei in the framework of two-component model at the Serpukhov energies. This model combines the leading-twist QCD and intrinsic charm contributions. It is shown that both contributions are comparable at 70 GeV energy of a proton, which makes possible the testing of the intrinsic charm predictions: the asymmetry between the leading and non-leading charm production and the A dependence of charm production. The asymmetry for D-bar/D mesons and Λ c + /Λ c - baryons and the cross section ratios for different nuclei are estimated [ru

  17. Prospects for detecting supersymmetric dark matter in the Galactic halo

    NARCIS (Netherlands)

    Springel, V.; White, S. D. M.; Frenk, C. S.; Navarro, J. F.; Jenkins, A.; Vogelsberger, M.; Wang, J.; Ludlow, A.; Helmi, A.

    2008-01-01

    Dark matter is the dominant form of matter in the Universe, but its nature is unknown. It is plausibly an elementary particle, perhaps the lightest supersymmetric partner of known particle species(1). In this case, annihilation of dark matter in the halo of the Milky Way should produce gamma-rays at

  18. Multifield stochastic particle production: beyond a maximum entropy ansatz

    Energy Technology Data Exchange (ETDEWEB)

    Amin, Mustafa A.; Garcia, Marcos A.G.; Xie, Hong-Yi; Wen, Osmond, E-mail: mustafa.a.amin@gmail.com, E-mail: marcos.garcia@rice.edu, E-mail: hxie39@wisc.edu, E-mail: ow4@rice.edu [Physics and Astronomy Department, Rice University, 6100 Main Street, Houston, TX 77005 (United States)

    2017-09-01

    We explore non-adiabatic particle production for N {sub f} coupled scalar fields in a time-dependent background with stochastically varying effective masses, cross-couplings and intervals between interactions. Under the assumption of weak scattering per interaction, we provide a framework for calculating the typical particle production rates after a large number of interactions. After setting up the framework, for analytic tractability, we consider interactions (effective masses and cross couplings) characterized by series of Dirac-delta functions in time with amplitudes and locations drawn from different distributions. Without assuming that the fields are statistically equivalent, we present closed form results (up to quadratures) for the asymptotic particle production rates for the N {sub f}=1 and N {sub f}=2 cases. We also present results for the general N {sub f} >2 case, but with more restrictive assumptions. We find agreement between our analytic results and direct numerical calculations of the total occupation number of the produced particles, with departures that can be explained in terms of violation of our assumptions. We elucidate the precise connection between the maximum entropy ansatz (MEA) used in Amin and Baumann (2015) and the underlying statistical distribution of the self and cross couplings. We provide and justify a simple to use (MEA-inspired) expression for the particle production rate, which agrees with our more detailed treatment when the parameters characterizing the effective mass and cross-couplings between fields are all comparable to each other. However, deviations are seen when some parameters differ significantly from others. We show that such deviations become negligible for a broad range of parameters when N {sub f}>> 1.

  19. Halo Star Lithium Depletion

    International Nuclear Information System (INIS)

    Pinsonneault, M. H.; Walker, T. P.; Steigman, G.; Narayanan, Vijay K.

    1999-01-01

    The depletion of lithium during the pre-main-sequence and main-sequence phases of stellar evolution plays a crucial role in the comparison of the predictions of big bang nucleosynthesis with the abundances observed in halo stars. Previous work has indicated a wide range of possible depletion factors, ranging from minimal in standard (nonrotating) stellar models to as much as an order of magnitude in models that include rotational mixing. Recent progress in the study of the angular momentum evolution of low-mass stars permits the construction of theoretical models capable of reproducing the angular momentum evolution of low-mass open cluster stars. The distribution of initial angular momenta can be inferred from stellar rotation data in young open clusters. In this paper we report on the application of these models to the study of lithium depletion in main-sequence halo stars. A range of initial angular momenta produces a range of lithium depletion factors on the main sequence. Using the distribution of initial conditions inferred from young open clusters leads to a well-defined halo lithium plateau with modest scatter and a small population of outliers. The mass-dependent angular momentum loss law inferred from open cluster studies produces a nearly flat plateau, unlike previous models that exhibited a downward curvature for hotter temperatures in the 7Li-Teff plane. The overall depletion factor for the plateau stars is sensitive primarily to the solar initial angular momentum used in the calibration for the mixing diffusion coefficients. Uncertainties remain in the treatment of the internal angular momentum transport in the models, and the potential impact of these uncertainties on our results is discussed. The 6Li/7Li depletion ratio is also examined. We find that the dispersion in the plateau and the 6Li/7Li depletion ratio scale with the absolute 7Li depletion in the plateau, and we use observational data to set bounds on the 7Li depletion in main-sequence halo

  20. Study of beam optics and beam halo by integrated modeling of negative ion beams from plasma meniscus formation to beam acceleration

    International Nuclear Information System (INIS)

    Miyamoto, K.; Okuda, S.; Hatayama, A.; Hanada, M.; Kojima, A.

    2013-01-01

    To understand the physical mechanism of the beam halo formation in negative ion beams, a two-dimensional particle-in-cell code for simulating the trajectories of negative ions created via surface production has been developed. The simulation code reproduces a beam halo observed in an actual negative ion beam. The negative ions extracted from the periphery of the plasma meniscus (an electro-static lens in a source plasma) are over-focused in the extractor due to large curvature of the meniscus.

  1. Study of beam optics and beam halo by integrated modeling of negative ion beams from plasma meniscus formation to beam acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K. [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Okuda, S.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Hanada, M.; Kojima, A. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 319-0913 (Japan)

    2013-01-14

    To understand the physical mechanism of the beam halo formation in negative ion beams, a two-dimensional particle-in-cell code for simulating the trajectories of negative ions created via surface production has been developed. The simulation code reproduces a beam halo observed in an actual negative ion beam. The negative ions extracted from the periphery of the plasma meniscus (an electro-static lens in a source plasma) are over-focused in the extractor due to large curvature of the meniscus.

  2. Tune-Based Halo Diagnostics

    International Nuclear Information System (INIS)

    Cameron, Peter

    2003-01-01

    Tune-based halo diagnostics can be divided into two categories -- diagnostics for halo prevention, and diagnostics for halo measurement. Diagnostics for halo prevention are standard fare in accumulators, synchrotrons, and storage rings, and again can be divided into two categories -- diagnostics to measure the tune distribution (primarily to avoid resonances), and diagnostics to identify instabilities (which will not be discussed here). These diagnostic systems include kicked (coherent) tune measurement, phase-locked loop (PLL) tune measurement, Schottky tune measurement, beam transfer function (BTF) measurements, and measurement of transverse quadrupole mode envelope oscillations. We refer briefly to tune diagnostics used at RHIC and intended for the SNS, and then present experimental results. Tune-based diagnostics for halo measurement (as opposed to prevention) are considerably more difficult. We present one brief example of tune-based halo measurement

  3. EWKino Production and Long-Lived particles at LHC

    CERN Document Server

    Verducci, M; The ATLAS collaboration

    2013-01-01

    The Large Hadron Collider has extended the reach of particle-physics experiments with a potential for discovery of new physics at the TeV scale and many searches have been carried out by both ATLAS and CMS. Searches for long-lived particles and electroweak “ino” production using 2012 LHV data have been carried by both ATLAS and CMS. The methodology of the searches (reconstruction techniques, background suppression, etc.) and the sensitivity of these searches are reviewed. Many models of physics beyond the Standard Model predict new particles with long lifetimes. Examples include Supersymmetry with R-parity violation, suppressed decays of the next-to-lightest Supersymmetric particle, or models with hidden sectors. The decay vertices of particles with lifetimes of order 10 ps to 10 ns can be efficiently identified by the ATLAS and CMS detectors. In addition, in quark and gluons collisions it is easy to produce coloured objects like gluinos and squarks, which decay typically to jets and MET, while the cross ...

  4. Hot Gas Halos in Galaxies

    Science.gov (United States)

    Mulchaey, John

    Most galaxy formation models predict that massive low-redshift disk galaxies are embedded in extended hot halos of externally accreted gas. Such gas appears necessary to maintain ongoing star formation in isolated spirals like the Milky Way. To explain the large population of red galaxies in rich groups and clusters, most galaxy evolution models assume that these hot gas halos are stripped completely when a galaxy enters a denser environment. This simple model has been remarkably successful at reproducing many observed properties of galaxies. Although theoretical arguments suggest hot gas halos are an important component in galaxies, we know very little about this gas from an observational standpoint. In fact, previous observations have failed to detect soft X-ray emission from such halos in disk galaxies. Furthermore, the assumption that hot gas halos are stripped completely when a galaxy enters a group or cluster has not been verified. We propose to combine proprietary and archival XMM-Newton observations of galaxies in the field, groups and clusters to study how hot gas halos are impacted by environment. Our proposed program has three components: 1) The deepest search to date for a hot gas halo in a quiescent spiral galaxy. A detection will confirm a basic tenet of disk galaxy formation models, whereas a non-detection will seriously challenge these models and impose new constraints on the growth mode and feedback history of disk galaxies. 2) A detailed study of the hot gas halos properties of field early-type galaxies. As environmental processes such as stripping are not expected to be important in the field, a study of hot gas halos in this environment will allow us to better understand how feedback and other internal processes impact hot gas halos. 3) A study of hot gas halos in the outskirts of groups and clusters. By comparing observations with our suite of simulations we can begin to understand what role the stripping of hot gas halos plays in galaxy

  5. New halo formation mechanism at the KEK compact energy recovery linac

    Science.gov (United States)

    Tanaka, Olga; Nakamura, Norio; Shimada, Miho; Miyajima, Tsukasa; Ueda, Akira; Obina, Takashi; Takai, Ryota

    2018-02-01

    The beam halo mitigation is a very important challenge for reliable and safe operation of a high-energy machine. A systematic beam halo study was conducted at the KEK compact energy recovery linac (cERL) since non-negligible beam loss was observed in the recirculation loop during a common operation. We found that the beam loss can be avoided by making use of the collimation system. Beam halo measurements have demonstrated the presence of vertical beam halos at multiple locations in the beam line (except the region near the electron gun). Based on these observations, we made a conjecture that the transverse beam halo is attributed to the longitudinal bunch tail arising at the photocathode. The transfer of particles from the longitudinal space to a transverse halo may have been observed and studied in other machines, considering nonlinear effects as their causes. However, our study demonstrates a new unique halo formation mechanism, in which a transverse beam halo can be generated by a longitudinal bunch tail due to transverse rf kicks from the accelerating (monopole) fields of the radio-frequency cavities. This halo formation occurs when nonrelativistic particles enter the cavities with a transverse offset, even if neither nonlinear optics nor nonlinear beam effects are present. A careful realignment of the injector system will mitigate the present halo. Another possible cure is to reduce the bunch tails by changing the photocathode material from the present GaAs to a multi-alkali that is known to have a shorter longitudinal tail.

  6. First Attempts at using Active Halo Control at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Joschka [CERN; Bruce, Roderik [CERN; Garcia Morales, Hector [CERN; Höfle, Wolfgang [CERN; Kotzian, Gerd [CERN; Kwee-Hinzmann, Regina [CERN; Langner, Andy [CERN; Mereghetti, Alessio [CERN; Quaranta, Elena [CERN; Redaelli, Stefano [CERN; Rossi, Adriana [CERN; Salvachua, Belen [CERN; Stancari, Giulio [Fermilab; Tomás, Rogelio [CERN; Valentino, Gianluca [CERN; Valuch, Daniel [CERN

    2016-06-01

    The beam halo population is a non-negligible factor for the performance of the LHC collimation system and the machine protection. In particular this could become crucial for aiming at stored beam energies of 700 MJ in the High Luminosity (HL-LHC) project, in order to avoid beam dumps caused by orbit jitter and to ensure safety during a crab cavity failure. Therefore several techniques to safely deplete the halo, i.e. active halo control, are under development. In a first attempt a novel way for safe halo depletion was tested with particle narrow-band excitation employing the LHC Transverse Damper (ADT). At an energy of 450 GeV a bunch selective beam tail scraping without affecting the core distribution was attempted. This paper presents the first measurement results, as well as a simple simulation to model the underlying dynamics.

  7. Multiparticle production in particle and nuclear collisions, 2

    International Nuclear Information System (INIS)

    Kanki, Takeshi; Kinoshita, Kisei; Sumiyoshi, Hiroyuki; Takagi, Fujio.

    1990-01-01

    Multiparticle dynamics is related to many branches of particle and nuclear physics. This book provides a comprehensive review which covers the whole domain of multiparticle dynamics. The review consists of five chapters. Chapter D, which is the first chapter of this volume, is titled 'Mechanism of Fragmentation' and contains six sections dealing with 'parton densities inside hadrons', 'hadron fragmentation and quark picture', 'recombination type models', 'quark fragmentation models in soft interaction', 'diquark and its fragmentation' and 'fragmentation in string models'. Chapter E 'Diffractive Production of Hadrons' discusses 'diffractive inelastic processes of composite particles', 'diffractive processes and triple-pomeron coupling', 'properties of diffractive inelastic final states', and 'nature of pomeron'. Chapter F 'Unified Descriptions' focuses on 'general chain picture', 'dual parton model', 'Monte Carlo simulations' and 'unification of hard and soft interactions'. Chapter G, titled 'Multiparticle Production in Hadron-Nucleus Collisions and Other Nuclear Processes' and contains 11 sections. Chapter H presents conclusions. (N.K.)

  8. LEP measurements on production, mass, lifetime of beauty particles

    International Nuclear Information System (INIS)

    Wormser, G.

    1993-10-01

    Present knowledge about the individual properties of the different beauty particles is discussed using the results of the LEP experiments. Individual lifetimes for B d 0 and B + are found to be equal within 10% whilst a 15% precision is reached for B s 0 and Λ b . The Λ b lifetime is found to be smaller than τ B + with a 2.7 σ significance. The production rate of each of these particles is measured at the 20% level. Preliminary evidence for Ξ b production has been reported. Finally, the B s 0 meson mass has been measured to be 5373 ± 4 MeV/c 2 . (author) 24 refs., 9 figs., 5 tabs

  9. Production and decay of supersymmetric particles at future colliders

    International Nuclear Information System (INIS)

    Bartl, A.; Majerotto, W.; Moesslacher, B.

    1991-01-01

    We describe how supersymmetric particles could be detected at the new colliders HERA, LEP 200, LHC, SSC, and at the possible future linear e + e - collider. We shall present theoretical predictions for production cross sections and decay probabilities, as well as for the important signatures. Our calculations will be based on the Minimal Supersymmetric Standard Model (MSSM) which is the simplest supersymmetric extension of the Standard Model. (authors)

  10. Radiolytic gas production in the alpha particle degradation of plastics

    International Nuclear Information System (INIS)

    Reed, D.T.; Hoh, J.; Emery, J.; Hobbs, D.

    1992-01-01

    Net gas generation due to alpha particle irradiation of polyethylene and polyvinyl chloride was investigated. Experiments were performed in an air environment at 30, 60, and 100 degree C. The predominant radiolytic degradation products of polyethylene were hydrogen and carbon dioxide with a wide variety of trace organic species noted. Irradiation of polyvinyl chloride resulted in the formation of HCl in addition to the products observed for polyethylene. For both plastic materials, a strong enhancement of net yields was noted at 100 degree C

  11. LHCf: physics results on forward particle production at LHC

    CERN Document Server

    Adriani, O

    2013-01-01

    The LHCf experiment is dedicated to the measurement of very forward particle production in the high energy hadron-hadron collisions at LHC, with the aim of improving the cosmic-ray air shower developments models. The detector has taken data in p-p collisions at $\\sqrt s$ = 900 GeV, 2.76 TeV and 7 TeV, and in p/Pb collisions at $\\sqrt s$ = 5 TeV. The results of forward production spectra of photons, neutral pions and neutrons, compared with the models most widely used in the High Energy Cosmic Ray physics, are presented in this paper.

  12. Structure and reactions of quantum halos

    International Nuclear Information System (INIS)

    Jensen, A.S.; Riisager, K.; Fedorov, D.V.; Garrido, E.

    2004-01-01

    This article provides an overview of the basic principles of the physics of quantum halo systems, defined as bound states of clusters of particles with a radius extending well into classically forbidden regions. Exploiting the consequences of this definition, the authors derive the conditions for occurrence in terms of the number of clusters, binding energy, angular momentum, cluster charges, and excitation energy. All these quantities must be small. The article discusses the transitions between different cluster divisions and the importance of thresholds for cluster or particle decay, with particular attention to the Efimov effect and the related exotic states. The pertinent properties can be described by the use of dimensionless variables. Then universal and specific properties can be distinguished, as shown in a series of examples selected from nuclear, atomic, and molecular systems. The neutron dripline is especially interesting for nuclei and negative ions for atoms. For molecules, in which the cluster division comes naturally, a wider range of possibilities exists. Halos in two dimensions have very different properties, and their states are easily spatially extended, whereas Borromean systems are unlikely and spatially confined. The Efimov effect and the Thomas collapse occur only for dimensions between 2.3 and 3.8 and thus not for 2. High-energy reactions directly probe the halo structure. The authors discuss the reaction mechanisms for high-energy nuclear few-body halo breakup on light, intermediate, and heavy nuclear targets. For light targets, the strong interaction dominates, while for heavy targets, the Coulomb interaction dominates. For intermediate targets these processes are of comparable magnitude. As in atomic and molecular physics, a geometric impact-parameter picture is very appropriate. Finally, the authors briefly consider the complementary processes involving electroweak probes available through beta decay, electromagnetic transitions, and

  13. Studies on inclusive meson resonance and particle production

    International Nuclear Information System (INIS)

    Saarikko, Heimo

    1978-01-01

    Production and decay of meson resonances are studied in medium energy meson-proton collisions. Strong evidence is found that hadronic collisions are dominated by resonance production. Especially the vector mesons have often large inclusive cross sections, typically of the order of few millibarns at the present energies. In all, a majority of pions and kaons appear to be decay products of resonances or other unstable particles. The detailed kinematics of the parent resonance's decays is found to play an important role in determining inclusive pion spectra. The squared transverse momentum distributions of hadrons heavier than the pion appear to have in common an exponential behaviour, with a universal slope for the esponential fall-off. The observed vector meson yields suggest that only a small fraction of the direct lepton production observed at large transverse momentum in nucleon-nucleon interactions is accounted for by the ''old'' vector mesons. An attempt has been made to separate out the central production and fragmentation components of the meson production. Both the central production and the fragmentation of the incoming meson are found to be important mechanisms in the non-strange meson production whereas the central production of strange meson resonances is rare at our energies. The ratios of the observed meson yields are found to be generally in good agreement with a simple quark-counting model. (author)

  14. An experiment on particle and jet production at midrapidity

    International Nuclear Information System (INIS)

    Kadija, K.; Paic, G.; Vranic, D.; Brady, F.P.; Draper, J.E.; Romero, J.L.; Carroll, J.; Ghazikhanian, V.; Gulmez, E.; Igo, G.J.; Trentalange, S.; Whitten, C. Jr.; Cherney, M.; Heck, W.; Renfordt, R.E.; Roehrich, D.; Stock, R.; Stroebele, H.; Wenig, S.; Hallman, T.; Madansky, L.; Anderson, B.; Keane, D.; Madey, R.; Watson, J.; Bieser, F.; Bloomer, M.A.; Cebra, D.; Christie, W.; Friedlander, E.; Greiner, D.; Gruhn, C.; Harris, J.W.; Huang, H.; Jacobs, P.; Lindstrom, P.; Matis, H.; McParland, C.; Naudet, C.; Odyniec, G.; Olson, D.; Poskanzer, A.M.; Rai, G.; Rasmussen, J.; Ritter, H.G.; Schambach, J.; Schroeder, L.S.; Seidl, P.A.; Symons, T.J.M.; Tonse, S.; Wieman, H.; Carmony, D.D.; Choi, Y.; Hirsch, A.; Hjort, E.; Porile, N.; Scharenberg, R.P.; Srivastava, B.; Tincknell, M.L.; Chacon, A.D.; Wolf, K.L.; Dominik, W.; Gazdzicki, M.; Braithwaite, W.J.; Cramer, J.G.; Prindle, D.; Trainor, T.A.; Breskin, A.; Chechik, R.; Fraenkel, Z.; Shor, A.; Tserruya, I.

    1990-09-01

    The aim of this experiment is to search for signatures of Quark-Gluon Plasma (QGP) formation and investigate the behavior of strongly interacting matter at high energy density. Since there is no single accepted signature for the QGP, it is essential to use a flexible detection system at RHIC that can simultaneously measure many experimental observables. The experiment will utilize two aspects of hadron production that are fundamentally new at RHIC: correlations between global observables on an event-by-event basis and the use of hard scattering of partons as a probe of the properties of high density nuclear matter. The event-by-event measurement of global observables--such as temperature, flavor composition, collision geometry, reaction dynamics, and energy or entropy density fluctuations--is possible because of the very high charged particle densities. Event-by-event fluctuations are expected in the vicinity of a phase change, so experiments must be sensitive to threshold-like features in experimental observables as a function of energy density. Full azimuthal coverage with good particle identification and continuous tracking is required to perform these measurements at momenta where the particle yields are maximal. Measurable jet yields at RHIC will allow investigations of hard QCD processes via both highly segmented calorimetry and high p t single particle measurements in a tracking system. A systematic study of particle and jet production will be carried out over a range of colliding nuclei from p + p through Au + Au, over a range of impact parameters from peripheral to central, and over the range of energies available at RHIC. Correlations between observables will be made on an event-by-event basis to isolate potentially interesting event types. In particular, correlations of jet properties with full event reconstruction may lead to some surprising new physics

  15. Multiple particle production processes in the ''light'' of quantum optics

    International Nuclear Information System (INIS)

    Friedlander, E.M.

    1990-09-01

    Ever since the observation that high-energy ''nuclear active'' cosmic-ray particles create bunches of penetrating particles upon hitting targets, a controversy has raged about whether these secondaries are created in a ''single act'' or whether many hadrons are just the result of an intra-nuclear cascade, yielding one meson in every step. I cannot escape the impression that: the latter kind of model appeals naturally as a consequence of an innate bio-morphism in our way of thinking and that in one guise or another it has tenaciously survived to this day, also for hadron-hadron collisions, via multi-peripheral models to the modern parton shower approach. Indeed, from the very beginning of theoretical consideration of multiparticle production, the possibility of many particles arising from a single ''hot'' system has been explored, with many fruitful results, not the least of which are the s 1/4 dependence of the mean produced particle multiplicity and the ''thermal'' shape of the P T spectra. An important consequence of the thermodynamical-hydrodynamical models is that particle emission is treated in analogy to black-body radiation, implying for the secondaries a set of specific Quantum-Statistical properties, very similar to those observed in quantum optics. From here on I shall try to review a number of implications and applications of this QS analogy in the study of multiplicity distributions of the produced secondaries. I will touch only in passing another very important topic of this class, the Bose-Einstein two-particle correlations

  16. Convergence properties of halo merger trees; halo and substructure merger rates across cosmic history

    Science.gov (United States)

    Poole, Gregory B.; Mutch, Simon J.; Croton, Darren J.; Wyithe, Stuart

    2017-12-01

    We introduce GBPTREES: an algorithm for constructing merger trees from cosmological simulations, designed to identify and correct for pathological cases introduced by errors or ambiguities in the halo finding process. GBPTREES is built upon a halo matching method utilizing pseudo-radial moments constructed from radially sorted particle ID lists (no other information is required) and a scheme for classifying merger tree pathologies from networks of matches made to-and-from haloes across snapshots ranging forward-and-backward in time. Focusing on SUBFIND catalogues for this work, a sweep of parameters influencing our merger tree construction yields the optimal snapshot cadence and scanning range required for converged results. Pathologies proliferate when snapshots are spaced by ≲0.128 dynamical times; conveniently similar to that needed for convergence of semi-analytical modelling, as established by Benson et al. Total merger counts are converged at the level of ∼5 per cent for friends-of-friends (FoF) haloes of size np ≳ 75 across a factor of 512 in mass resolution, but substructure rates converge more slowly with mass resolution, reaching convergence of ∼10 per cent for np ≳ 100 and particle mass mp ≲ 109 M⊙. We present analytic fits to FoF and substructure merger rates across nearly all observed galactic history (z ≤ 8.5). While we find good agreement with the results presented by Fakhouri et al. for FoF haloes, a slightly flatter dependence on merger ratio and increased major merger rates are found, reducing previously reported discrepancies with extended Press-Schechter estimates. When appropriately defined, substructure merger rates show a similar mass ratio dependence as FoF rates, but with stronger mass and redshift dependencies for their normalization.

  17. Phenomenology of supersymmetric particle production process at the LHC

    International Nuclear Information System (INIS)

    Trenkel, Maike Kristina

    2009-01-01

    We study the hadronic production of strongly interacting SUSY particles in the framework of the MSSM. In particular, we consider top-squark pair, gluino. squark pair, and same sign squark-squark pair production processes. Aiming at precise theoretical predictions, we calculate the cross section contributions of electroweak origin up to the one-loop level. We find sizable effects both from tree-level electroweak subprocesses and next-to-leading order electroweak corrections, reaching the 20% level in kinematical distributions. In a second part of this thesis, we investigate the phenomenology of R-parity violating B 3 SUSY models with the lightest stau (τ 1 ) being the LSP. We analyze the possible τ 1 decay modes, taking into account the dynamical generation of non-zero R-parity violating couplings at lower scales. As an application of our studies which is interesting for experiments at particle accelators, we discuss single slepton production at the LHC and give numerical results for single smuon production. (orig.)

  18. Phenomenology of supersymmetric particle production process at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Trenkel, Maike Christina

    2009-07-20

    We study the hadronic production of strongly interacting SUSY particles in the framework of the MSSM. In particular, we consider top-squark pair, gluino. squark pair, and same sign squark-squark pair production processes. Aiming at precise theoretical predictions, we calculate the cross section contributions of electroweak origin up to the one-loop level. We find sizable effects both from tree-level electroweak subprocesses and next-to-leading order electroweak corrections, reaching the 20% level in kinematical distributions. In a second part of this thesis, we investigate the phenomenology of R-parity violating B{sub 3} SUSY models with the lightest stau ({tau}{sub 1}) being the LSP. We analyze the possible {tau}{sub 1} decay modes, taking into account the dynamical generation of non-zero R-parity violating couplings at lower scales. As an application of our studies which is interesting for experiments at particle accelators, we discuss single slepton production at the LHC and give numerical results for single smuon production. (orig.)

  19. Particle-production mechanism in relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Bush, B.W.; Nix, J.R.

    1994-01-01

    We discuss the production of particles in relativistic heavy-ion collisions through the mechanism of massive bremsstrahlung, in which massive mesons are emitted during rapid nucleon acceleration. This mechanism is described within the framework of classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic heavy-ion collisions that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons, and particle production. Inclusion of the finite nucleon size cures the difficulties with preacceleration and runaway solutions that have plagued the classical theory of self-interacting point particles. For the soft reactions that dominate nucleon-nucleon collisions, a significant fraction of the incident center-of-mass energy is radiated through massive bremsstrahlung. In the present version of the theory, this radiated energy is in the form of neutral scalar (σ) and neutral vector (ω) mesons, which subsequently decay primarily into pions with some photons also. Additional meson fields that are known to be important from nucleon-nucleon scattering experiments should be incorporated in the future, in which case the radiated energy would also contain isovector pseudoscalar (π + , π - , π 0 ), isovector scalar (δ + , δ - , δ 0 ), isovector vector (ρ + , ρ - , ρ 0 ), and neutral pseudoscalar (η) mesons

  20. HALOE test and evaluation software

    Science.gov (United States)

    Edmonds, W.; Natarajan, S.

    1987-01-01

    Computer programming, system development and analysis efforts during this contract were carried out in support of the Halogen Occultation Experiment (HALOE) at NASA/Langley. Support in the major areas of data acquisition and monitoring, data reduction and system development are described along with a brief explanation of the HALOE project. Documented listings of major software are located in the appendix.

  1. Proceedings of the meeting on multi-particle production

    International Nuclear Information System (INIS)

    Ochiai, Fumio; Suzuki, Atsuto; Noda, Hujio; Miyamura, Osamu

    1980-02-01

    This study meeting was held on September 6 and 7, 1979, at the National Laboratory for High Energy Physics for the purposes of discussing multiple production phenomena including the experiments in KEK, FNAL and CERN and those in cosmic ray domain and obtaining the clues to solve their mechanism. Altogether, 31 papers were presented on the hardware and software aspects of the multiple production phenomena at high energy. The production of particles in high energy p-p reaction and its mechanism, the inclusive production of high meson resonance in p-p collision, the inclusive hadron production in low momentum region at high energy, the cluster analysis using minimal spanning tree, the hadron beam jet in small transverse momentum region, quark-diquark cascade model and the hadron production in proton beam jet, quark recoupling model, the local number fluctuation in pp 405 GeV/c scattering and its analysis, the mode of change of the formula of Kopylov-Podgoretsky-Cocconi when incoherent and coherent emission sources coexist, the motion of fire balls in the mechanism of multiple production, inelastic diffraction and the geometrical structure of protons, cylinder amplitude, nuclear targets as the probes for hadrons and the constituents, the experimental study of pion-nucleus interaction and so on were discussed. (Kako, I.)

  2. Inflaton decay and heavy particle production with negative coupling

    International Nuclear Information System (INIS)

    Greene, B.R.; Prokopec, T.; Roos, T.G.

    1997-01-01

    We study the decay of the inflaton in a general Z 2 xZ 2 symmetric two scalar theory. Since the dynamics of the system is dominated by states with large occupation numbers which admit a semiclassical description, the decay can be studied by solving the classical equations of motion on the lattice. Of particular interest is the case when the cross coupling between the inflaton and the second scalar field is negative, which is naturally allowed in many realistic models. While the inflaton decays via parametric resonance in the positive coupling case we find that for negative coupling there is a new mechanism of particle production which we call negative coupling instability. Because of this new mechanism the variances of the fields grow significantly larger before the production is shut off by the back reaction of the created particles, which could have important consequences for symmetry restoration by nonthermal phase transitions. We also find that heavy particles are produced much more efficiently with negative coupling, which is of prime importance for GUT baryogenesis. Using a simple toy model for baryogenesis and the results of our lattice simulations we show that for natural values of the cross coupling enough 10 14 GeV bosons are created to produce a baryon to entropy ratio consistent with observation. This is to be contrasted with the situation for positive coupling, where the value of the cross coupling required to produce such massive particles is technically unnatural. In addition to our numerical results we obtain analytical estimates for the maximum variances of the fields in an expanding universe for all cases of interest: massive and massless inflaton, positive and negative cross coupling, with and without significant self-interactions for the second field. copyright 1997 The American Physical Society

  3. The effect of stellar feedback on a Milky Way-like galaxy and its gaseous halo

    NARCIS (Netherlands)

    Marasco, Antonino; Debattista, Victor P.; Fraternali, Filippo; van der Hulst, Thijs; Wadsley, James; Quinn, Thomas; Roškar, Rok

    We present the study of a set of N-body+smoothed particle hydrodynamics simulations of a Milky Way-like system produced by the radiative cooling of hot gas embedded in a dark matter halo. The galaxy and its gaseous halo evolve for 10 Gyr in isolation, which allows us to study how internal processes

  4. THE HALO MERGER RATE IN THE MILLENNIUM SIMULATION AND IMPLICATIONS FOR OBSERVED GALAXY MERGER FRACTIONS

    International Nuclear Information System (INIS)

    Genel, Shy; Genzel, Reinhard; Bouche, Nicolas; Naab, Thorsten; Sternberg, Amiel

    2009-01-01

    We have developed a new method to extract halo merger rates from the Millennium Simulation. First, by removing superfluous mergers that are artifacts of the standard friends-of-friends (FOF) halo identification algorithm, we find a lower merger rate compared to previous work. The reductions are more significant at lower redshifts and lower halo masses, and especially for minor mergers. Our new approach results in a better agreement with predictions from the extended Press-Schechter model. Second, we find that the FOF halo finder overestimates the halo mass by up to 50% for halos that are about to merge, which leads to an additional ∼20% overestimate of the merger rate. Therefore, we define halo masses by including only particles that are gravitationally bound to their FOF groups. We provide new best-fitting parameters for a global formula to account for these improvements. In addition, we extract the merger rate per progenitor halo, as well as per descendant halo. The merger rate per progenitor halo is the quantity that should be related to observed galaxy merger fractions when they are measured via pair counting. At low-mass/redshift, the merger rate increases moderately with mass and steeply with redshift. At high enough mass/redshift (for the rarest halos with masses a few times the 'knee' of the mass function), these trends break down, and the merger rate per progenitor halo decreases with mass and increases only moderately with redshift. Defining the merger rate per progenitor halo also allows us to quantify the rate at which halos are being accreted onto larger halos, in addition to the minor and major merger rates. We provide an analytic formula that converts any given merger rate per descendant halo into a merger rate per progenitor halo. Finally, we perform a direct comparison between observed merger fractions and the fraction of halos in the Millennium Simulation that have undergone a major merger during the recent dynamical friction time, and find a

  5. Resummation for supersymmetric particle production at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Brensing, Silja Christine

    2011-05-10

    The search for supersymmetry is among the most important tasks at current and future colliders. Especially the production of coloured supersymmetric particles would occur copiously in hadronic collisions. Since these production processes are of high relevance for experimental searches accurate theoretical predictions are needed. Higher-order corrections in quantum chromodynamics (QCD) to these processes are dominated by large logarithmic terms due to the emission of soft gluons from initial-state and final-state particles. A systematic treatment of these logarithms to all orders in perturbation theory is provided by resummation methods. We perform the resummation of soft gluons at next-to-leading-logarithmic (NLL) accuracy for all possible production processes in the framework of the Minimal Supersymmetric Standard Model. In particular we consider pair production processes of mass-degenerate light-flavour squarks and gluinos as well as the pair production of top squarks and non-mass-degenerate bottom squarks. We present analytical results for all considered processes including the soft anomalous dimensions. Moreover numerical predictions for total cross sections and transverse-momentum distributions for both the Large Hadron Collider (LHC) and the Tevatron are presented. We provide an estimate of the theoretical uncertainty due to scale variation and the parton distribution functions. The inclusion of NLL corrections leads to a considerable reduction of the theoretical uncertainty due to scale variation and to an enhancement of the next-to-leading order (NLO) cross section predictions. The size of the soft-gluon corrections and the reduction in the scale uncertainty are most significant for processes involving gluino production. At the LHC, where the sensitivity to squark and gluino masses ranges up to 3 TeV, the corrections due to NLL resummation over and above the NLO predictions can be as high as 35 % in the case of gluino-pair production, whereas at the

  6. Production of neutrons in particle accelerators: a PNRI safety concern

    International Nuclear Information System (INIS)

    Garcia, Corazon M.; Cayabo, Lynette B.; Artificio, Thelma P.; Melendez, Johnylen V.; Piquero, Myrna E.; Parami, Vangeline K.

    2002-09-01

    In the safety assessment made for the first cyclotron facility in the Philippines, that is the cyclotron in the P.E.T. (Positron Emission Tomography) center of the St. Luke's Medical Center, the concern on the production of neutrons associated with the operation of particle accelerators has been identified. This takes into consideration the principles in the operation of particle accelerators and the associated production of neutrons resulting from their operation, the hazards and risks in their operation. The Bureau of Health Devices and Technology (BHDT) of the Department of Health in the Philippines regulates and controls the presently existing six (6) linear accelerators distributed in different hospitals in the country, being classified as x-ray producing devices. From the results of this study, it is evident that the production of neutrons from the operation of accelerators, produces neutrons and that activation due to neutrons can form radioactive materials. The PNRI (Philippine Nuclear Research Institute) being mandated by law to regulate and control any equipment or devices producing or utilizing radioactive materials should take the proper steps to subject all accelerator facilities and devices in the Philippines such as linear accelerators under its regulatory control in the same manner as it did with the first cyclotron in the country. (Author)

  7. Galactic warps and the shape of heavy halos

    International Nuclear Information System (INIS)

    Sparke, L.S.

    1984-01-01

    The outer disks of many spiral galaxies are bent away from the plane of the inner disk; the abundance of these warps suggests that they are long-lived. Isolated galactic disks have long been thought to have no discrete modes of vertical oscillation under their own gravity, and so to be incapable of sustaining persistent warps. However, the visible disk contains only a fraction of the galactic mass; an invisible galactic halo makes up the rest. This paper presents an investigation of vertical warping modes in self-gravitating disks, in the imposed potential due to an axisymmetric unseen massive halo. If the halo matter is distributed so that the free precession rate of a test particle decreases with radius near the edge of the disk, then the disk has a discrete mode of vibration; oblate halos which become rapidly more flattened at large radii, and uniformly prolate halos, satisfy this requirement. Otherwise, the disk has no discrete modes and so cannot maintain a long-lived warp, unless the edge is sharply truncated. Computed mode shapes which resemble the observed warps can be found for halo masses consistent with those inferred from galactic rotation curves

  8. Dissipative dark matter halos: The steady state solution. II.

    Science.gov (United States)

    Foot, R.

    2018-05-01

    Within the mirror dark matter model and dissipative dark matter models in general, halos around galaxies with active star formation (including spirals and gas-rich dwarfs) are dynamical: they expand and contract in response to heating and cooling processes. Ordinary type II supernovae (SNe) can provide the dominant heat source, which is possible if kinetic mixing interaction exists with strength ɛ ˜10-9- 10-10 . Dissipative dark matter halos can be modeled as a fluid governed by Euler's equations. Around sufficiently isolated and unperturbed galaxies the halo can relax to a steady state configuration, where heating and cooling rates locally balance and hydrostatic equilibrium prevails. These steady state conditions can be solved to derive the physical properties, including the halo density and temperature profiles, for model galaxies. Here, we consider idealized spherically symmetric galaxies within the mirror dark particle model, as in our earlier paper [Phys. Rev. D 97, 043012 (2018), 10.1103/PhysRevD.97.043012], but we assume that the local halo heating in the SN vicinity dominates over radiative sources. With this assumption, physically interesting steady state solutions arise which we compute for a representative range of model galaxies. The end result is a rather simple description of the dark matter halo around idealized spherically symmetric systems, characterized in principle by only one parameter, with physical properties that closely resemble the empirical properties of disk galaxies.

  9. Dissipative dark matter halos: The steady state solution

    Science.gov (United States)

    Foot, R.

    2018-02-01

    Dissipative dark matter, where dark matter particle properties closely resemble familiar baryonic matter, is considered. Mirror dark matter, which arises from an isomorphic hidden sector, is a specific and theoretically constrained scenario. Other possibilities include models with more generic hidden sectors that contain massless dark photons [unbroken U (1 ) gauge interactions]. Such dark matter not only features dissipative cooling processes but also is assumed to have nontrivial heating sourced by ordinary supernovae (facilitated by the kinetic mixing interaction). The dynamics of dissipative dark matter halos around rotationally supported galaxies, influenced by heating as well as cooling processes, can be modeled by fluid equations. For a sufficiently isolated galaxy with a stable star formation rate, the dissipative dark matter halos are expected to evolve to a steady state configuration which is in hydrostatic equilibrium and where heating and cooling rates locally balance. Here, we take into account the major cooling and heating processes, and numerically solve for the steady state solution under the assumptions of spherical symmetry, negligible dark magnetic fields, and that supernova sourced energy is transported to the halo via dark radiation. For the parameters considered, and assumptions made, we were unable to find a physically realistic solution for the constrained case of mirror dark matter halos. Halo cooling generally exceeds heating at realistic halo mass densities. This problem can be rectified in more generic dissipative dark matter models, and we discuss a specific example in some detail.

  10. The gamma-ray-flux PDF from galactic halo substructure

    International Nuclear Information System (INIS)

    Lee, Samuel K.; Ando, Shin'ichiro; Kamionkowski, Marc

    2009-01-01

    One of the targets of the recently launched Fermi Gamma-ray Space Telescope is a diffuse gamma-ray background from dark-matter annihilation or decay in the Galactic halo. N-body simulations and theoretical arguments suggest that the dark matter in the Galactic halo may be clumped into substructure, rather than smoothly distributed. Here we propose the gamma-ray-flux probability distribution function (PDF) as a probe of substructure in the Galactic halo. We calculate this PDF for a phenomenological model of halo substructure and determine the regions of the substructure parameter space in which the PDF may be distinguished from the PDF for a smooth distribution of dark matter. In principle, the PDF allows a statistical detection of substructure, even if individual halos cannot be detected. It may also allow detection of substructure on the smallest microhalo mass scales, ∼ M ⊕ , for weakly-interacting massive particles (WIMPs). Furthermore, it may also provide a method to measure the substructure mass function. However, an analysis that assumes a typical halo substructure model and a conservative estimate of the diffuse background suggests that the substructure PDF may not be detectable in the lifespan of Fermi in the specific case that the WIMP is a neutralino. Nevertheless, for a large range of substructure, WIMP annihilation, and diffuse background models, PDF analysis may provide a clear signature of substructure

  11. Remapping dark matter halo catalogues between cosmological simulations

    Science.gov (United States)

    Mead, A. J.; Peacock, J. A.

    2014-05-01

    We present and test a method for modifying the catalogue of dark matter haloes produced from a given cosmological simulation, so that it resembles the result of a simulation with an entirely different set of parameters. This extends the method of Angulo & White, which rescales the full particle distribution from a simulation. Working directly with the halo catalogue offers an advantage in speed, and also allows modifications of the internal structure of the haloes to account for non-linear differences between cosmologies. Our method can be used directly on a halo catalogue in a self-contained manner without any additional information about the overall density field; although the large-scale displacement field is required by the method, this can be inferred from the halo catalogue alone. We show proof of concept of our method by rescaling a matter-only simulation with no baryon acoustic oscillation (BAO) features to a more standard Λ cold dark matter model containing a cosmological constant and a BAO signal. In conjunction with the halo occupation approach, this method provides a basis for the rapid generation of mock galaxy samples spanning a wide range of cosmological parameters.

  12. Strange-particle production via the weak interaction

    International Nuclear Information System (INIS)

    Adera, G. B.; Van Der Ventel, B. I. S.; Niekerk, D. D. van; Mart, T.

    2010-01-01

    The differential cross sections for the neutrino-induced weak charged current production of strange particles in the threshold energy region are presented. The general representation of the weak hadronic current is newly developed in terms of eighteen unknown invariant amplitudes to parametrize the hadron vertex. The Born-term approximation is used for the numerical calculations in the framework of the Cabibbo theory and SU(3) symmetry. For unpolarized octet baryons four processes are investigated, whereas in the case of polarized baryons only one process is chosen to study the sensitivity of the differential cross section to the various polarizations of the initial-state nucleon and the final-state hyperon.

  13. Dark matter from gravitational particle production at reheating

    Energy Technology Data Exchange (ETDEWEB)

    Markkanen, Tommi [Department of Physics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Nurmi, Sami, E-mail: tommi.markkanen@kcl.ac.uk, E-mail: sami.t.nurmi@jyu.fi [Department of Physics, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä (Finland)

    2017-02-01

    We show that curvature induced particle production at reheating generates adiabatic dark matter if there are non-minimally coupled spectator scalars weakly coupled to visible matter. The observed dark matter abundance implies an upper bound on spectator masses m and non-minimal coupling values ξ. For example, assuming quadratic inflation, instant reheating and a single spectator scalar with only gravitational couplings, the observed dark matter abundance is obtained for m ∼ 0.1 GeV and ξ ∼ 1. Larger mass and coupling values of the spectator are excluded as they would lead to overproduction of dark matter.

  14. Dark matter from gravitational particle production at reheating

    International Nuclear Information System (INIS)

    Markkanen, Tommi; Nurmi, Sami

    2017-01-01

    We show that curvature induced particle production at reheating generates adiabatic dark matter if there are non-minimally coupled spectator scalars weakly coupled to visible matter. The observed dark matter abundance implies an upper bound on spectator masses m and non-minimal coupling values ξ. For example, assuming quadratic inflation, instant reheating and a single spectator scalar with only gravitational couplings, the observed dark matter abundance is obtained for m ∼ 0.1 GeV and ξ ∼ 1. Larger mass and coupling values of the spectator are excluded as they would lead to overproduction of dark matter.

  15. Black holes with halos

    Science.gov (United States)

    Monten, Ruben; Toldo, Chiara

    2018-02-01

    We present new AdS4 black hole solutions in N =2 gauged supergravity coupled to vector and hypermultiplets. We focus on a particular consistent truncation of M-theory on the homogeneous Sasaki–Einstein seven-manifold M 111, characterized by the presence of one Betti vector multiplet. We numerically construct static and spherically symmetric black holes with electric and magnetic charges, corresponding to M2 and M5 branes wrapping non-contractible cycles of the internal manifold. The novel feature characterizing these nonzero temperature configurations is the presence of a massive vector field halo. Moreover, we verify the first law of black hole mechanics and we study the thermodynamics in the canonical ensemble. We analyze the behavior of the massive vector field condensate across the small-large black hole phase transition and we interpret the process in the dual field theory.

  16. Measurement of the particle production properties in ATLAS

    CERN Document Server

    Bruni, Alessia; The ATLAS collaboration

    2017-01-01

    Measurements of the particle production properties with the ATLAS detector A correct modelling of the underlying event in proton-proton collisions is important for the proper simulation of kinematic distributions of high-energy collisions. The ATLAS collaboration extended previous studies at 7 TeV with a leading track or jet or Z boson by a new study at 13 TeV, measuring the number and transverse-momentum sum of charged particles as a function of pseudorapidity and azimuthal angle in dependence of the reconstructed leading track. These measurements are sensitive to the underlying-event as well as the onset of hard emissions. The results are compared to predictions of several MC generators. A similar comparison between measurements and MC generator predictions will be shown for the strange meson content in topquark pair events. Studies of particle correlations in high-energy collisions can provide valuable insights into the detailed understanding of the space-time geometry of the hadronization region. The ATLA...

  17. Investigation of Rare Particle Production in High Energy Nuclear Collisions

    International Nuclear Information System (INIS)

    Crawford, Henry J.; Engelage, Jon M.

    1999-01-01

    Our program is an investigation of the hadronization process through measurement of rare particle production in high energy nuclear interactions. Such collisions of heavy nuclei provide an environment similar in energy density to the conditions in the Big Bang. We are currently involved in two major experiments to study this environment, E896 at the AGS and STAR at RHIC. We have completed our physics running of E896, a search for the H dibaryon and measurement of hyperon production in AuAu collisions, and are in the process of analyzing the data. We have produced the electronics and software for the STAR trigger and will begin to use these tools to search for anti-nuclei and strange hadrons when RHIC turns on later this year

  18. REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Cassano, R.; Brunetti, G.; Venturi, T.; Kale, R. [INAF/IRA, via Gobetti 101, I-40129 Bologna (Italy); Ettori, S. [INAF/Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Pratt, G. W. [Laboratoire AIM, IRFU/Service dAstrophysique-CEA/DSM-CNRS-Université Paris Diderot, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Dolag, K. [University Observatory Munich, Scheinerstr. 1, D-81679 Munich (Germany); Markevitch, M. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-11-10

    Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R{sub 500} as P{sub 1.4}∼L{sup 2.1±0.2}{sub 500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L{sub 500} > 5 × 10{sup 44} erg s{sup –1}) clusters branch into two populations—radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P{sub 1.4} scales with the cluster integrated SZ signal within R{sub 500}, measured by Planck, as P{sub 1.4}∼Y{sup 2.05±0.28}{sub 500}, in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that 'SZ-luminous' Y{sub 500} > 6 × 10{sup –5} Mpc{sup 2} clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the

  19. X-ray haloes around supernova remnants

    International Nuclear Information System (INIS)

    Morfill, G.E.; Aschenbach, B.

    1984-01-01

    Recent observations of the Cas-A supernova remnant have shown X-ray emissions not only from the interior, but also from a fainter 'halo' extending beyond what is normally regarded as the outer boundary, or shock front. The authors suggest that this may be due to the diffusion of energetic, charged particles out of the remnant giving rise to precursor structure of the type predicted by the theory of diffusive shock acceleration. If this is the case we are seeing thermal emission from ambient gas heated by compression and wave dissipation. (author)

  20. X-ray haloes around supernova remnants

    Energy Technology Data Exchange (ETDEWEB)

    Morfill, G.E.; Aschenbach, B. (Max-Planck-Institut fuer Physik und Astrophysik, Garching (Germany, F.R.). Inst. fuer Extraterrestrische Physik); Drury, L.O' C. (Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.))

    1984-09-27

    Recent observations of the Cas-A supernova remnant have shown X-ray emissions not only from the interior, but also from a fainter 'halo' extending beyond what is normally regarded as the outer boundary, or shock front. The authors suggest that this may be due to the diffusion of energetic charged particles out of the remnant giving rise to precursor structure of the type predicted by the theory of diffusive shock acceleration. If this is the case we are seeing thermal emission from ambient gas heated by compression and wave dissipation.

  1. Disruption, vertical displacement event and halo current characterization for ITER

    International Nuclear Information System (INIS)

    Wesley, J.; Fujisawa, N.; Ortolani, S.; Putvinski, S.; Rosenbluth, M.N.

    1997-01-01

    Characteristics, in ITER, of plasma disruptions, vertical displacement events (VDEs) and the conversion of plasma current to runaway electron current in a disruption are presented. In addition to the well known potential of disruptions to produce rapid thermal energy and plasma current quenches and theoretical predictions that show the likelihood of ∼ 50% runaway conversion, an assessment of VDE and halo current characteristics in vertically elongated tokamaks shows that disruptions in ITER will result in VDEs with peak in-vessel halo currents of up to 50% of the predisruption plasma current and with toroidal peaking factors (peak/average current density) of up to 4:1. However, the assessment also shows an inverse correlation between the halo current magnitude and the toroidal peaking factor; hence, ITER VDEs can be expected to have a product of normalized halo current magnitude times toroidal peaking factor of ≤ 75%. (author). 3 refs, 2 figs, 3 tabs

  2. Continuous production of nanostructured particles using spatial atomic layer deposition

    International Nuclear Information System (INIS)

    Ommen, J. Ruud van; Kooijman, Dirkjan; Niet, Mark de; Talebi, Mojgan; Goulas, Aristeidis

    2015-01-01

    In this paper, the authors demonstrate a novel spatial atomic layer deposition (ALD) process based on pneumatic transport of nanoparticle agglomerates. Nanoclusters of platinum (Pt) of ∼1 nm diameter are deposited onto titania (TiO 2 ) P25 nanoparticles resulting to a continuous production of an active photocatalyst (0.12–0.31 wt. % of Pt) at a rate of about 1 g min −1 . Tuning the precursor injection velocity (10–40 m s −1 ) enhances the contact between the precursor and the pneumatically transported support flows. Decreasing the chemisorption temperature (from 250 to 100 °C) results in more uniform distribution of the Pt nanoclusters as it decreases the reaction rate as compared to the rate of diffusion into the nanoparticle agglomerates. Utilizing this photocatalyst in the oxidation reaction of Acid Blue 9 showed a factor of five increase of the photocatalytic activity compared to the native P25 nanoparticles. The use of spatial particle ALD can be further expanded to deposition of nanoclusters on porous, micron-sized particles and to the production of core–shell nanoparticles enabling the robust and scalable manufacturing of nanostructured powders for catalysis and other applications

  3. Production and global transport of Titan's sand particles

    Science.gov (United States)

    Barnes, Jason W.; Lorenz, Ralph D.; Radebaugh, Jani; Hayes, Alexander G.; Arnold, Karl; Chandler, Clayton

    2015-06-01

    Previous authors have suggested that Titan's individual sand particles form by either sintering or by lithification and erosion. We suggest two new mechanisms for the production of Titan's organic sand particles that would occur within bodies of liquid: flocculation and evaporitic precipitation. Such production mechanisms would suggest discrete sand sources in dry lakebeds. We search for such sources, but find no convincing candidates with the present Cassini Visual and Infrared Mapping Spectrometer coverage. As a result we propose that Titan's equatorial dunes may represent a single, global sand sea with west-to-east transport providing sources and sinks for sand in each interconnected basin. The sand might then be transported around Xanadu by fast-moving Barchan dune chains and/or fluvial transport in transient riverbeds. A river at the Xanadu/Shangri-La border could explain the sharp edge of the sand sea there, much like the Kuiseb River stops the Namib Sand Sea in southwest Africa on Earth. Future missions could use the composition of Titan's sands to constrain the global hydrocarbon cycle.

  4. The Excursion Set Theory of Halo Mass Functions, Halo Clustering, and Halo Growth

    Science.gov (United States)

    Zentner, Andrew R.

    I review the excursion set theory with particular attention toward applications to cold dark matter halo formation and growth, halo abundance, and halo clustering. After a brief introduction to notation and conventions, I begin by recounting the heuristic argument leading to the mass function of bound objects given by Press and Schechter. I then review the more formal derivation of the Press-Schechter halo mass function that makes use of excursion sets of the density field. The excursion set formalism is powerful and can be applied to numerous other problems. I review the excursion set formalism for describing both halo clustering and bias and the properties of void regions. As one of the most enduring legacies of the excursion set approach and one of its most common applications, I spend considerable time reviewing the excursion set theory of halo growth. This section of the review culminates with the description of two Monte Carlo methods for generating ensembles of halo mass accretion histories. In the last section, I emphasize that the standard excursion set approach is the result of several simplifying assumptions. Dropping these assumptions can lead to more faithful predictions and open excursion set theory to new applications. One such assumption is that the height of the barriers that define collapsed objects is a constant function of scale. I illustrate the implementation of the excursion set approach for barriers of arbitrary shape. One such application is the now well-known improvement of the excursion set mass function derived from the "moving" barrier for ellipsoidal collapse. I also emphasize that the statement that halo accretion histories are independent of halo environment in the excursion set approach is not a general prediction of the theory. It is a simplifying assumption. I review the method for constructing correlated random walks of the density field in the more general case. I construct a simple toy model to illustrate that excursion set

  5. Nuclear emulsion experiments on particle production at high energies

    International Nuclear Information System (INIS)

    Otterlund, I.

    1976-08-01

    Various experimental results, including multiplicities of shower-particles and heavy prong particles, correlations between them and single particle distributions, from proton-emulsion nucleus reactions in the energy range 200-400 GeV are presented. (Auth.)

  6. Precise predictions for supersymmetric particle production at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Rothering, Marcel

    2016-07-01

    One of the main objectives of the Large Hadron Collider (LHC) is the search for physics beyond the Standard Model. Among the most promising candidates is the Minimal Supersymmetric Standard Model (MSSM) which postulates the existence of further particles. Since none of these supersymmetric particles have been found yet, their mass limits have been shifted to high values. Hence, with the available energy of the LHC they would always be produced close to their production threshold. This leads to predictions for cross sections which are characterized by the presence of dominant logarithmic terms stemming from multiple soft gluon emission. These contributions spoil the convergence of the perturbative series and require a resummation to predict reliable results in these critical kinematical phase space regions. As the attention of experimental searches has been shifted towards electroweak supersymmetric particle production at the LHC, we update in this thesis our predictions for direct slepton pair production at proton-proton collision to next-to-leading order (NLO) matched to resummation at the next-to-leading logarithmic (NLL) accuracy. As a benchmark scenario we choose simplified models which have the advantage of only containing a few relevant physical parameters. They are now commonly adopted by the experimental collaborations for slepton and electroweak gaugino searches. We find that the scale dependence is drastically reduced by including NLL corrections, especially for large slepton masses. For increasing mass limits we hint towards the significance of next-to-next-to-leading logarithmic contributions to the cross section. By using modern Monte Carlo techniques we reanalyze ATLAS and CMS results for slepton searches for different assumptions about the compositions of the sleptons and their neutralino decay products. We observe similar mass limits for selectrons and smuons as both collaborations and find that masses for left-handed (right-handed) selectrons and

  7. Bose-Einstein condensate haloes embedded in dark energy

    Science.gov (United States)

    Membrado, M.; Pacheco, A. F.

    2018-04-01

    Context. We have studied clusters of self-gravitating collisionless Newtonian bosons in their ground state and in the presence of the cosmological constant to model dark haloes of dwarf spheroidal (dSph) galaxies. Aim. We aim to analyse the influence of the cosmological constant on the structure of these systems. Observational data of Milky Way dSph galaxies allow us to estimate the boson mass. Methods: We obtained the energy of the ground state of the cluster in the Hartree approximation by solving a variational problem in the particle density. We have also developed and applied the virial theorem. Dark halo models were tested in a sample of 19 galaxies. Galaxy radii, 3D deprojected half-light radii, mass enclosed within them, and luminosity-weighted averages of the square of line-of-sight velocity dispersions are used to estimate the particle mass. Results: Cosmological constant repulsive effects are embedded in one parameter ξ. They are appreciable for ξ > 10-5. Bound structures appear for ξ ≤ ξc = 1.65 × 10-4, what imposes a lower bound for cluster masses as a function of the particle mass. In principle, these systems present tunnelling through a potential barrier; however, after estimating their mean lifes, we realize that their existence is not affected by the age of the Universe. When Milky Way dSph galaxies are used to test the model, we obtain 3.5-1.0+1.3 × 10-22 eV for the particle mass and a lower limit of 5.1-2.8+2.2 × 106 M⊙ for bound haloes. Conclusions: Our estimation for the boson mass is in agreement with other recent results which use different methods. From our particle mass estimation, the treated dSph galaxies would present dark halo masses 5-11 ×107 M⊙. With these values, they would not be affected by the cosmological constant (ξ 10-5) would already feel their effects. Our model that includes dark energy allows us to deal with these dark haloes. Assuming quantities averaged in the sample of galaxies, 10-5 < ξ ≤ ξc dark

  8. The Galactic Halo in Mixed Dark Matter Cosmologies

    NARCIS (Netherlands)

    Anderhalden, D.; Diemand, J.; Bertone, G.; Macciò, A.V.; Schneider, A.

    2012-01-01

    A possible solution to the small scale problems of the cold dark matter (CDM) scenario is that the dark matter consists of two components, a cold and a warm one. We perform a set of high resolution simulations of the Milky Way halo varying the mass of the WDM particle (mWDM) and the cosmic dark

  9. Insight into particle production mechanisms from angular correlations of identified particles in pp collisions measured by ALICE

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Two-particle angular correlations are a robust tool which provide access to the underlying physics phenomena of particle production in collisions of both protons and heavy ions by studying distributions of particles in pseudorapidity and azimuthal angle difference. The correlation measurement is sensitive to several phenomena, including mini-jets, elliptic flow, Bose-Einstein correlations, resonance decays, conservation laws, which can be separated by selections of momentum, particle type and by analysing the shapes of the correlation structures. In this talk, we report measurements of the correlations of identified particles and their antiparticles (for pions, kaons, protons, and lambdas) at low transverse momenta in pp collisions at sqrt(s) = 7 TeV, recently submitted for publication by the ALICE Collaboration [arXiv:1612.08975]. The analysis reveals differences in particle production between baryons and mesons. The correlation functions for mesons exhibit the expected peak dominated by effects of mini-jet...

  10. The influence of final state interaction on two-particle correlations in multiple production of particles and resonances

    International Nuclear Information System (INIS)

    Lednicky, R.; Lyuboshitz, V.L.

    1996-01-01

    The structure of pair correlations of interacting particles moving with nearby velocities is analysed. A general formalism of the two-particle space-time density matrix, taking into account the space-time coherence of the production process, is developed. The influence of strong final state interaction on two-particle correlations in the case of the production of a system resonance + particle is investigated in detail. It is shown that in the limit of small distances between the resonance and particle production points the effect of final state interaction is enhanced due to logarithmic singularity of the triangle diagram. Numerical estimates indicate that, in this limit, the effect of strong final state interaction becomes important even for two-pion correlations. (author)

  11. Disc-halo interactions in ΛCDM

    Science.gov (United States)

    Bauer, Jacob S.; Widrow, Lawrence M.; Erkal, Denis

    2018-05-01

    We present a new method for embedding a stellar disc in a cosmological dark matter halo and provide a worked example from a Λ cold dark matter zoom-in simulation. The disc is inserted into the halo at a redshift z = 3 as a zero-mass rigid body. Its mass and size are then increased adiabatically while its position, velocity, and orientation are determined from rigid-body dynamics. At z = 1, the rigid disc (RD) is replaced by an N-body disc whose particles sample a three-integral distribution function (DF). The simulation then proceeds to z = 0 with live disc (LD) and halo particles. By comparison, other methods assume one or more of the following: the centre of the RD during the growth phase is pinned to the minimum of the halo potential, the orientation of the RD is fixed, or the live N-body disc is constructed from a two rather than three-integral DF. In general, the presence of a disc makes the halo rounder, more centrally concentrated, and smoother, especially in the innermost regions. We find that methods in which the disc is pinned to the minimum of the halo potential tend to overestimate the amount of adiabatic contraction. Additionally, the effect of the disc on the subhalo distribution appears to be rather insensitive to the disc insertion method. The LD in our simulation develops a bar that is consistent with the bars seen in late-type spiral galaxies. In addition, particles from the disc are launched or `kicked up' to high galactic latitudes.

  12. El halo de la memoria

    OpenAIRE

    GAVINO ROSELLÓ, AARÓN

    2017-01-01

    The halo effect is one of the most classic cognitive biases of psychology, and one that we can observe frequently in everyday life. It consists in the realization of an erroneous generalization from a single characteristic or quality of an object or a person, that is, we make a previous judgment from which, we generalize the rest of characteristics. The halo effect manifests itself as continuous in our life. For example, if someone is very handsome or attractive we attribute another series...

  13. Gravitational particle production in inflation. A fresh look

    Science.gov (United States)

    Yajnik, Urjit A.

    1990-01-01

    Gravitational production of energy density in the case of a minimally coupled scalar field is treated using quantum field theory in curved spacetime. We calculate 0> of the produced particles. The results for the massless case can be applied to gravitons, but an unphysically large contribution is found from wavelengths longer than the horizon size. Gravitons of wavelengths smaller that the horizon give rise to energy density ϱgrav~H4 (H being the Hubble constant during inflation). In the case of a light scalar of mass m≪H the long wavelengths contribute ϱm~H5/m, which too can become unphysically large for sufficiently small m. We also discuss how this energy density subsequently evolves. Address after August 1989: Physics Department, Indian Institute of Technology, Bombay 400 076, India.

  14. Investigating the Wave Nature of the Outer Envelope of Halo Coronal Mass Ejections

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ryun-Young [College of Science, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States); Vourlidas, Angelos, E-mail: rkwon@gmu.edu [The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 (United States)

    2017-02-20

    We investigate the nature of the outer envelope of halo coronal mass ejections (H-CMEs) using multi-viewpoint observations from the Solar Terrestrial Relations Observatory-A , -B , and SOlar and Heliospheric Observatory coronagraphs. The 3D structure and kinematics of the halo envelopes and the driving CMEs are derived separately using a forward modeling method. We analyze three H-CMEs with peak speeds from 1355 to 2157 km s{sup −1}; sufficiently fast to drive shocks in the corona. We find that the angular widths of the halos range from 192° to 252°, while those of the flux ropes range between only 58° and 91°, indicating that the halos are waves propagating away from the CMEs. The halo widths are in agreement with widths of Extreme Ultraviolet (EUV) waves in the low corona further demonstrating the common origin of these structures. To further investigate the wave nature of the halos, we model their 3D kinematic properties with a linear fast magnetosonic wave model. The model is able to reproduce the position of the halo flanks with realistic coronal medium assumptions but fails closer to the CME nose. The CME halo envelope seems to arise from a driven wave (or shock) close to the CME nose, but it is gradually becoming a freely propagating fast magnetosonic wave at the flanks. This interpretation provides a simple unifying picture for CME halos, EUV waves, and the large longitudinal spread of solar energetic particles.

  15. Puzzle of the folding potential on the nuclear halo reactions

    International Nuclear Information System (INIS)

    Ismail, Atef; Lee, Yen Cheong; Mahmoud, Z.M.M.

    2015-01-01

    Folding potentials of the elastic scattering drip-line nuclei at various incident energies is one method to study nuclear matter density distributions and nuclear radii. The nuclei with density distributions consisting of a bulk (core) and an outer layer (halo), dilute and spatially extended are called the halo nuclei caused for the weak particle binding. Several halo nuclei are studied and many potential candidates are identified. All the cross-sections of the elastic scattering for the drip-line nuclei 11 Be and 6 He, are calculated to understand the exotic properties of these nuclei starting from its structure, extended radius, nuclear size till the large total reaction cross-sections for these nuclei when it interacts with a stable target 12 C. (author)

  16. Black hole production in particle collisions and higher curvature gravity

    International Nuclear Information System (INIS)

    Rychkov, Vyacheslav S.

    2004-01-01

    The problem of black hole production in trans-Planckian particle collisions is revisited, in the context of large extra dimensions scenarios of TeV-scale gravity. The validity of the standard description of this process (two colliding Aichelburg-Sexl shock waves in classical Einstein gravity) is questioned. It is observed that the classical spacetime has large curvature along the transverse collision plane, as signaled by the curvature invariant (R μνλσ ) 2 . Thus quantum gravity effects, and in particular higher curvature corrections to the Einstein gravity, cannot be ignored. To give a specific example of what may happen, the collision is reanalyzed in the Einstein-Lanczos-Lovelock gravity theory, which modifies the Einstein-Hilbert Lagrangian by adding a particular 'Gauss-Bonnet' combination of curvature squared terms. The analysis uses a series of approximations, which reduce the field equations to a tractable second order nonlinear PDE of the Monge-Ampere type. It is found that the resulting spacetime is significantly different from the pure Einstein case in the future of the transverse collision plane. These considerations cast serious doubts on the geometric cross section estimate, which is based on the classical Einstein gravity description of the black hole production process

  17. Productive interactions: heavy particles and non-Gaussianity

    International Nuclear Information System (INIS)

    Flauger, Raphael; Mirbabayi, Mehrdad; Senatore, Leonardo; Silverstein, Eva

    2017-01-01

    We analyze the shape and amplitude of oscillatory features in the primordial power spectrum and non-Gaussianity induced by periodic production of heavy degrees of freedom coupled to the inflaton φ. We find that non-adiabatic production of particles can contribute effects which are detectable or constrainable using cosmological data even if their time-dependent masses are always heavier than the scale φ̇ 1/2 , much larger than the Hubble scale. This provides a new role for UV completion, consistent with the criteria from effective field theory for when heavy fields cannot be integrated out. This analysis is motivated in part by the structure of axion monodromy, and leads to an additional oscillatory signature in a subset of its parameter space. At the level of a quantum field theory model that we analyze in detail, the effect arises consistently with radiative stability for an interesting window of couplings up to of order ∼< 1. The amplitude of the bispectrum and higher-point functions can be larger than that for Resonant Non-Gaussianity, and its signal/noise may be comparable to that of the corresponding oscillations in the power spectrum (and even somewhat larger within a controlled regime of parameters). Its shape is distinct from previously analyzed templates, but was partly motivated by the oscillatory equilateral searches performed recently by the Planck collaboration. We also make some general comments about the challenges involved in making a systematic study of primordial non-Gaussianity.

  18. Productive interactions: heavy particles and non-Gaussianity

    Energy Technology Data Exchange (ETDEWEB)

    Flauger, Raphael [Department of Physics, The University of Texas at Austin, Austin, TX, 78712 (United States); Mirbabayi, Mehrdad [Institute for Advanced Study, Princeton, NJ 08540 (United States); Senatore, Leonardo; Silverstein, Eva, E-mail: flauger@physics.ucsd.edu, E-mail: mehrdadm@ias.edu, E-mail: senatore@stanford.edu, E-mail: evas@slac.stanford.edu [Stanford Institute for Theoretical Physics, Stanford University, Stanford, CA 94305 (United States)

    2017-10-01

    We analyze the shape and amplitude of oscillatory features in the primordial power spectrum and non-Gaussianity induced by periodic production of heavy degrees of freedom coupled to the inflaton φ. We find that non-adiabatic production of particles can contribute effects which are detectable or constrainable using cosmological data even if their time-dependent masses are always heavier than the scale φ̇{sup 1/2}, much larger than the Hubble scale. This provides a new role for UV completion, consistent with the criteria from effective field theory for when heavy fields cannot be integrated out. This analysis is motivated in part by the structure of axion monodromy, and leads to an additional oscillatory signature in a subset of its parameter space. At the level of a quantum field theory model that we analyze in detail, the effect arises consistently with radiative stability for an interesting window of couplings up to of order ∼< 1. The amplitude of the bispectrum and higher-point functions can be larger than that for Resonant Non-Gaussianity, and its signal/noise may be comparable to that of the corresponding oscillations in the power spectrum (and even somewhat larger within a controlled regime of parameters). Its shape is distinct from previously analyzed templates, but was partly motivated by the oscillatory equilateral searches performed recently by the Planck collaboration. We also make some general comments about the challenges involved in making a systematic study of primordial non-Gaussianity.

  19. Halo modelling in chameleon theories

    Energy Technology Data Exchange (ETDEWEB)

    Lombriser, Lucas; Koyama, Kazuya [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Li, Baojiu, E-mail: lucas.lombriser@port.ac.uk, E-mail: kazuya.koyama@port.ac.uk, E-mail: baojiu.li@durham.ac.uk [Institute for Computational Cosmology, Ogden Centre for Fundamental Physics, Department of Physics, University of Durham, Science Laboratories, South Road, Durham, DH1 3LE (United Kingdom)

    2014-03-01

    We analyse modelling techniques for the large-scale structure formed in scalar-tensor theories of constant Brans-Dicke parameter which match the concordance model background expansion history and produce a chameleon suppression of the gravitational modification in high-density regions. Thereby, we use a mass and environment dependent chameleon spherical collapse model, the Sheth-Tormen halo mass function and linear halo bias, the Navarro-Frenk-White halo density profile, and the halo model. Furthermore, using the spherical collapse model, we extrapolate a chameleon mass-concentration scaling relation from a ΛCDM prescription calibrated to N-body simulations. We also provide constraints on the model parameters to ensure viability on local scales. We test our description of the halo mass function and nonlinear matter power spectrum against the respective observables extracted from large-volume and high-resolution N-body simulations in the limiting case of f(R) gravity, corresponding to a vanishing Brans-Dicke parameter. We find good agreement between the two; the halo model provides a good qualitative description of the shape of the relative enhancement of the f(R) matter power spectrum with respect to ΛCDM caused by the extra attractive gravitational force but fails to recover the correct amplitude. Introducing an effective linear power spectrum in the computation of the two-halo term to account for an underestimation of the chameleon suppression at intermediate scales in our approach, we accurately reproduce the measurements from the N-body simulations.

  20. Halo modelling in chameleon theories

    International Nuclear Information System (INIS)

    Lombriser, Lucas; Koyama, Kazuya; Li, Baojiu

    2014-01-01

    We analyse modelling techniques for the large-scale structure formed in scalar-tensor theories of constant Brans-Dicke parameter which match the concordance model background expansion history and produce a chameleon suppression of the gravitational modification in high-density regions. Thereby, we use a mass and environment dependent chameleon spherical collapse model, the Sheth-Tormen halo mass function and linear halo bias, the Navarro-Frenk-White halo density profile, and the halo model. Furthermore, using the spherical collapse model, we extrapolate a chameleon mass-concentration scaling relation from a ΛCDM prescription calibrated to N-body simulations. We also provide constraints on the model parameters to ensure viability on local scales. We test our description of the halo mass function and nonlinear matter power spectrum against the respective observables extracted from large-volume and high-resolution N-body simulations in the limiting case of f(R) gravity, corresponding to a vanishing Brans-Dicke parameter. We find good agreement between the two; the halo model provides a good qualitative description of the shape of the relative enhancement of the f(R) matter power spectrum with respect to ΛCDM caused by the extra attractive gravitational force but fails to recover the correct amplitude. Introducing an effective linear power spectrum in the computation of the two-halo term to account for an underestimation of the chameleon suppression at intermediate scales in our approach, we accurately reproduce the measurements from the N-body simulations

  1. Fluorosis: halo effect

    International Nuclear Information System (INIS)

    Diaz Madriz, Jose Esteban; Granados Quesada, Maria Pamela; Lopez Chacon, Angelica Maria; Monge Cantillo, Carol Paola; Munoz Aguero, Geiner Andres; Vargas Vargas, Jorge Andres

    2013-01-01

    The halo effect was determined from the consumption of potatoes from Tierra Blanca de Cartago and Palmira de Zarcero. Seminars were held to get to know the topic of fluorosis. A mini health fair was held to explain the effects of fluoride in a population affected by it. Samples of water and forest type potato were collected in the area of Zarcero and San Juan de Chicoa. Measurements of the samples were made in the Chemistry Laboratory of the Universidad de Costa Rica. 20 mg of potato from each zone and 80 ml of distilled water were weighed and then liquefied. Each shake was dispensed in 2 clean test tubes and 7 samples were obtained, of which, 2 test tubes contained the liquefied 1, 2 tubes the liquefied 2, 1 tube with the Rio Reventado water centrifuged. 1 tube with Zarcero irrigation water and 1 tube with distilled water, for the subsequent analysis of fluoride concentration. The samples were taken to the LAMBDA Chemical Laboratory, where the ion chromatography test was performed on each of the samples. A concentration of fluorides of 0.73 ppm was obtained in the water of the Rio Reventado, while a concentration of less than 0.60 ppm was obtained in the water collected in Zarcero. The highest concentration of fluoride was presented in the potato from the area of Palmira de Zarcero with 2.41 ppm compared to that obtained in Cartago, with a lower concentration of 1.34 ppm. The maximum recommended concentration was exceeded in both results. A concentration less than 0.02 ppm was obtained in the analysis of distilled water as a control test [es

  2. Production of sized particles of uranium oxides and uranium oxyfluorides

    International Nuclear Information System (INIS)

    Knudsen, I.E.; Randall, C.C.

    1976-01-01

    A process is claimed for converting uranium hexafluoride (UF 6 ) to uranium dioxide (UO 2 ) of a relatively large particle size in a fluidized bed reactor by mixing uranium hexafluoride with a mixture of steam and hydrogen and by preliminary reacting in an ejector gaseous uranium hexafluoride with steam and hydrogen to form a mixture of uranium and oxide and uranium oxyfluoride seed particles of varying sizes, separating the larger particles from the smaller particles in a cyclone separator, recycling the smaller seed particles through the ejector to increase their size, and introducing the larger seed particles from the cyclone separator into a fluidized bed reactor where the seed particles serve as nuclei on which coarser particles of uranium dioxide are formed. 9 claims, 2 drawing figures

  3. NLO corrections to production of heavy particles at hadron colliders

    International Nuclear Information System (INIS)

    Pagani, Davide

    2013-01-01

    In this thesis we study specific aspects of the production of heavy particles at hadron colliders, with emphasis on precision predictions including next-to-leading order (NLO) corrections from the strong and electroweak interactions. In the first part of the thesis we consider the top quark charge asymmetry. In particular, we discuss in detail the calculation of the electroweak contributions from the asymmetric part of the top quark pair production cross section at O(α 2 s α) and O(α 2 ) and their numerical impact on predictions for the asymmetry measurements at the Tevatron. These electroweak contributions provide a non-negligible addition to the QCD-induced asymmetry with the same overall sign and, in general, enlarge the Standard Model predictions by a factor around 1.2, diminishing the deviations from experimental measurements. In the second part of the thesis we consider the production of squarks, the supersymmetric partners of quarks, at the Large Hadron Collider (LHC). We discuss the calculation of the contribution of factorizable NLO QCD corrections to the production of squark-squark pairs combined at fully differential level with squark decays. Combining the production process with two different configurations for the squark decays, our calculation is used to provide precise phenomenological predictions for two different experimental signatures that are important for the search of supersymmetry at the LHC. We focus, for one signature, on the impact of our results on important physical differential distributions and on cut-and-count searches performed by the ATLAS and CMS collaborations. Considering the other signature, we analyze the effects from NLO QCD corrections and from the combination of production and decays on distributions relevant for parameter determination. In general, factorizable NLO QCD corrections have to be taken into account to obtain precise phenomenological predictions for the analyzed distributions and inclusive quantities. Moreover

  4. Production of uranium-molybdenum particles by spark-erosion

    International Nuclear Information System (INIS)

    Cabanillas, E.D.; Lopez, M.; Pasqualini, E.E.; Cirilo Lombardo, D.J.

    2004-01-01

    With the spark-erosion method we have produced spheroidal particles of an uranium-molybdenum alloy using pure water as dielectric. The particles were characterized by optical metallography, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Mostly spherical particles of UO 2 with a distinctive size distribution with peaks centered at 70 and 10 μm were obtained. The particles have central inclusions of U and Mo compounds

  5. Production of uranium-molybdenum particles by spark-erosion

    Energy Technology Data Exchange (ETDEWEB)

    Cabanillas, E.D. E-mail: cabanill@cnea.gov.ar; Lopez, M.; Pasqualini, E.E.; Cirilo Lombardo, D.J

    2004-01-01

    With the spark-erosion method we have produced spheroidal particles of an uranium-molybdenum alloy using pure water as dielectric. The particles were characterized by optical metallography, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Mostly spherical particles of UO{sub 2} with a distinctive size distribution with peaks centered at 70 and 10 {mu}m were obtained. The particles have central inclusions of U and Mo compounds.

  6. Nuclear halo and its related reactions

    International Nuclear Information System (INIS)

    Zhang Huanqiao

    2005-01-01

    In order to search proton halo, the reaction cross sections of 27,28 P, 29 S and the corresponding isotones on Si target were measured at intermediate energies. The measured reaction cross sections of the N=12 and 13 isotones show an abrupt increase at Z=15. The experimental results for the isotones with Z=14 as well as 28 P can be well described by the modified Glauber theory of the optical limit approach. The enhancement of the reaction cross sections for 28 P could be explained in the modified Glauber theory with an enlarged core. Theoretical analysis with the modified Glauber theory of the optical limit and few-body approaches underpredicted the experimental data of 27 P. Our theoretical analysis shows that an enlarged core together with proton halo is probably the mechanism responsible for the enhancement of the cross sections for the reaction of 27 P+ 28 Si. In addition, we find from the experimental results that 29 S may have a moderate proton halo structure. Except the nuclei near or at drop-lines, halo may appear in the excited states of stable nuclei. By means of the asymptotic normalization coefficients (ANC's) extracted from transfer reactions of 11 B(d, p) 12 B, 12 C(d, p) 13 C, and H( 6 He, n) 6 Li, we have verified that the second ( Jπ = 2 - ) and third (Jπ = 1 - ) excited states in 12 B and the first (Jπ =1/2 + ) excited state in 13 C are the neutron halo states, while the second excited state (3.56 MeV, Jπ = 0 + ) in 6 Li is a proton-neutron halo state. We have proposed a procedure to extract the probability for valence particle being out of the binding potential from the measured nuclear asymptotic normalization coefficients. With this procedure, available data regarding the nuclear halo candidates are systematically analyzed and a number of halo nuclei are confirmed. Based on these results we have got a much relaxed condition for nuclear halo occurrence. Furthermore, we have presented the scaling laws for the dimensionless quantity 2 >/R 2 of

  7. Annihilation physics of exotic galactic dark matter particles

    Science.gov (United States)

    Stecker, F. W.

    1990-01-01

    Various theoretical arguments make exotic heavy neutral weakly interacting fermions, particularly those predicted by supersymmetry theory, attractive candidates for making up the large amount of unseen gravitating mass in galactic halos. Such particles can annihilate with each other, producing secondary particles of cosmic-ray energies, among which are antiprotons, positrons, neutrinos, and gamma-rays. Spectra and fluxes of these annihilation products can be calculated, partly by making use of positron electron collider data and quantum chromodynamic models of particle production derived therefrom. These spectra may provide detectable signatures of exotic particle remnants of the big bang.

  8. Relation Between Initial Cosmological Conditions and the Properties of Dark Matter Haloes

    International Nuclear Information System (INIS)

    Semenov, Vadim

    2013-01-01

    The core-cusp problem is one of the essential issues in modern cosmology. The Entropy Theory of haloes Evolution recently suggested by Lukash, Doroshkevich and Mikheeva is one of the possible solutions to this problem. This work compares some results of numerical simulation of Large-Scale Structure with the conclusions of the Entropy Theory in order to verify this theory. The numerical simulation was performed in a volume 100 Mpc/h in a side using ∼ 17 million particles. Dark matter particles, which then form virialized haloes, were found in the initial perturbation field. This work investigates the distribution of these dark matter particles and measures the velocity dispersion profiles. It also traces evolution of haloes entropy profiles. On the whole, simulation results correspond to Entropy Theory of haloes evolution

  9. Beyond assembly bias: exploring secondary halo biases for cluster-size haloes

    Science.gov (United States)

    Mao, Yao-Yuan; Zentner, Andrew R.; Wechsler, Risa H.

    2018-03-01

    Secondary halo bias, commonly known as `assembly bias', is the dependence of halo clustering on a halo property other than mass. This prediction of the Λ Cold Dark Matter cosmology is essential to modelling the galaxy distribution to high precision and interpreting clustering measurements. As the name suggests, different manifestations of secondary halo bias have been thought to originate from halo assembly histories. We show conclusively that this is incorrect for cluster-size haloes. We present an up-to-date summary of secondary halo biases of high-mass haloes due to various halo properties including concentration, spin, several proxies of assembly history, and subhalo properties. While concentration, spin, and the abundance and radial distribution of subhaloes exhibit significant secondary biases, properties that directly quantify halo assembly history do not. In fact, the entire assembly histories of haloes in pairs are nearly identical to those of isolated haloes. In general, a global correlation between two halo properties does not predict whether or not these two properties exhibit similar secondary biases. For example, assembly history and concentration (or subhalo abundance) are correlated for both paired and isolated haloes, but follow slightly different conditional distributions in these two cases. This results in a secondary halo bias due to concentration (or subhalo abundance), despite the lack of assembly bias in the strict sense for cluster-size haloes. Due to this complexity, caution must be exercised in using any one halo property as a proxy to study the secondary bias due to another property.

  10. Nanoparticle production by UV irradiation of combustion generated soot particles

    International Nuclear Information System (INIS)

    Stipe, Christopher B.; Choi, Jong Hyun; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

    2004-01-01

    Laser ablation of surfaces normally produce high temperature plasmas that are difficult to control. By irradiating small particles in the gas phase, we can better control the size and concentration of the resulting particles when different materials are photofragmented. Here, we irradiate soot with 193 nm light from an ArF excimer laser. Irradiating the original agglomerated particles at fluences ranging from 0.07 to 0.26 J/cm 2 with repetition rates of 20 and 100 Hz produces a large number of small, unagglomerated particles, and a smaller number of spherical agglomerated particles. Mean particle diameters from 20 to 50 nm are produced from soot originally having a mean electric mobility diameter of 265nm. We use a non-dimensional parameter, called the photon/atom ratio (PAR), to aid in understanding the photofragmentation process. This parameter is the ratio of the number of photons striking the soot particles to the number of the carbon atoms contained in the soot particles, and is a better metric than the laser fluence for analyzing laser-particle interactions. These results suggest that UV photofragmentation can be effective in controlling particle size and morphology, and can be a useful diagnostic for studying elements of the laser ablation process

  11. Hadronic J/psi and charmed particle production and correlating quark rearrangement model

    International Nuclear Information System (INIS)

    Nishitani, Tadashi

    1979-01-01

    On the basis of the correlating quark rearrangement model, the exclusive and inclusive production cross sections of J/psi and charmed particles in hadron collisions are calculated. It is shown that the inclusive production cross section of charmed particles is several tens of μb at p sub( l) -- 100 GeV/c in hadron collisions. The OZI rule is discussed in connection with the production mechanism of J/psi particles. (author)

  12. Are baryonic galactic halos possible

    International Nuclear Information System (INIS)

    Olive, K.A.; Hegyi, D.J.

    1986-01-01

    There is little doubt from the rotation curves of spiral galaxies that galactic halos must contain large amounts of dark matter. In this contribution, the authors review arguments which indicate that it is very unlikely that galactic halos contain substantial amounts of baryonic matter. While the authors would like to be able to present a single argument which would rule out baryonic matter, at the present time they are only able to present a collection of arguments each of which argues against one form of baryonic matter. These include: 1) snowballs; 2) gas; 3) low mass stars and Jupiters; 4) high mass stars; and 5) high metalicity objects such as rooks or dust. Black holes, which do not have a well defined baryon number, are also a possible candidate for halo matter. They briefly discuss black holes

  13. Halo vest effect on balance.

    Science.gov (United States)

    Richardson, J K; Ross, A D; Riley, B; Rhodes, R L

    2000-03-01

    To determine the effect of a halo vest, a cervical orthosis, on clinically relevant balance parameters. Subjects performed unipedal stance (with eyes open and closed, on both firm and soft surfaces) and functional reach, with and without the application of a halo vest. A convenience sample of 12 healthy young subjects, with an equal number of men and women. Seconds for unipedal stance (maximum 45); inches for functional reach. Both unipedal stance times and functional reach (mean +/- standard deviation) were significantly decreased with the halo vest as compared to without it (29.1+/-5.8 vs. 32.8+/-6.4 seconds, p = .002; 12.9+/-1.4 vs. 15.1+/-2.1 inches, prisk for a fall, which could have devastating consequences.

  14. The Angular Momentum of Baryons and Dark Matter Halos Revisited

    Science.gov (United States)

    Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

    2011-01-01

    Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

  15. Beauty is distractive: particle production during multifield inflation

    Energy Technology Data Exchange (ETDEWEB)

    Battefeld, Diana; Battefeld, Thorsten [Institute for Astrophysics, University of Göttingen, Friedrich Hund Platz 1, D-37077 Göttingen (Germany); Byrnes, Christian [Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld (Germany); Langlois, David, E-mail: dbattefe@astro.physik.uni-goettingen.de, E-mail: tbattefe@astro.physik.uni-goettingen.de, E-mail: byrnes@physik.uni-bielefeld.de, E-mail: langlois@apc.univ-paris7.fr [APC (CNRS-Université Paris 7), 10, rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)

    2011-08-01

    We consider a two-dimensional model of inflation, where the inflationary trajectory is ''deformed'' by a grazing encounter with an Extra Species/Symmetry Point (ESP) after the observable cosmological scales have left the Hubble radius. The encounter entails a sudden production of particles, whose backreaction causes a bending of the trajectory and a temporary decrease in speed, both of which are sensitive to initial conditions. This ''modulated'' effect leads to an additional contribution to the curvature perturbation, which can be dominant if the encounter is close. We compute associated non-Gaussianities, the bispectrum and its scale dependence as well as the trispectrum, which are potentially detectable in many cases. In addition, we consider a direct modulation of the coupling to the light field at the ESP via a modulaton field, a mixed scenario whereby the modulaton is identified with a second inflaton, and an extended Extra Species Locus (ESL); all of these scenarios lead to similar additional contributions to observables. We conclude that inflaton interactions throughout inflation are strongly constrained if primordial non-Gaussianities remain unobserved in current experiments such as PLANCK. If they are observed, an ESP encounter leaves additional signatures on smaller scales which may be used to identify the model.

  16. Multiparticle Production in Particle and Nuclear Collisions. I

    Science.gov (United States)

    Kanki, T.; Kinoshita, K.; Sumiyoshi, H.; Takagi, F.

    The dominant phenomenon in high-energy particle and nuclear collisions is multiple production of hadrons. This had attracted may physicists in 1950's, the period of the first remarkable development of particle physics. Multiparticle production was already observed in cosmic-ray experiments and expected to be explained as a natural consequence of the strong Yukawa interaction. Statistical and hydrodynamical models were then proposed by Fermi, Landau and others. These theories are still surviving even today as a prototype of modern ``fire-ball'' models. After twenty years, a golden age came in this field of physics. It was closely related to the rapid development of accelerator facilities, especially, the invention of colliding-beam machines which yield high enough center-of-mass energies for studying reactions with high multiplicity. Abundant data on final states of multiparticle production have been accumulated mainly by measuring inclusive cross sections and multiplicity distributions. In super high-energy bar{p}p collisions at CERN S pmacr pS Collider, we confirmed the increasing total cross section and found violations of many scaling laws which seemed to be valid at lower energies. This suggests a fundamental complexity of the multiparticle phenomena and offers new materials for further development of theoretical investigations. In the same period, studies of constituent (quark-gluon) structure of hadrons had also been develped. Nowadays, pysicists believe that the quantum chromodynamics (QCD) is the fundamental law of the hadronic world. Multiparticle dynamics should also be described by QCD. We have known that the hard-jet phenomena are well explained by the perturbative QCD. On the other hand, the soft processes are considered to be non-perturbative phenomena which have not yet been solved, and related to the mechanism of the color confinement and formation of strings or color-flux tubes. Multiparticle production would offer useful information on this

  17. Multiparticle Production in Particle and Nuclear Collisions. II

    Science.gov (United States)

    Kanki, T.; Kinoshita, K.; Sumiyoshi, H.; Takagi, F.

    The dominant phenomenon in high-energy particle and nuclear collisions is multiple production of hadrons. This had attracted may physicists in 1950's, the period of the first remarkable development of particle physics. Multiparticle production was already observed in cosmic-ray experiments and expected to be explained as a natural consequence of the strong Yukawa interaction. Statistical and hydrodynamical models were then proposed by Fermi, Landau and others. These theories are still surviving even today as a prototype of modern ``fire-ball'' models. After twenty years, a golden age came in this field of physics. It was closely related to the rapid development of accelerator facilities, especially, the invention of colliding-beam machines which yield high enough center-of-mass energies for studying reactions with high multiplicity. Abundant data on final states of multiparticle production have been accumulated mainly by measuring inclusive cross sections and multiplicity distributions. In super high-energy bar{p}p collisions at CERN S pmacr pS Collider, we confirmed the increasing total cross section and found violations of many scaling laws which seemed to be valid at lower energies. This suggests a fundamental complexity of the multiparticle phenomena and offers new materials for further development of theoretical investigations. In the same period, studies of constituent (quark-gluon) structure of hadrons had also been develped. Nowadays, pysicists believe that the quantum chromodynamics (QCD) is the fundamental law of the hadronic world. Multiparticle dynamics should also be described by QCD. We have known that the hard-jet phenomena are well explained by the perturbative QCD. On the other hand, the soft processes are considered to be non-perturbative phenomena which have not yet been solved, and related to the mechanism of the color confinement and formation of strings or color-flux tubes. Multiparticle production would offer useful information on this

  18. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    CMS Collaboration

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. In this talk we will describ...

  19. Pushing down the low-mass halo concentration frontier with the Lomonosov cosmological simulations

    Science.gov (United States)

    Pilipenko, Sergey V.; Sánchez-Conde, Miguel A.; Prada, Francisco; Yepes, Gustavo

    2017-12-01

    We introduce the Lomonosov suite of high-resolution N-body cosmological simulations covering a full box of size 32 h-1 Mpc with low-mass resolution particles (2 × 107 h-1 M⊙) and three zoom-in simulations of overdense, underdense and mean density regions at much higher particle resolution (4 × 104 h-1 M⊙). The main purpose of this simulation suite is to extend the concentration-mass relation of dark matter haloes down to masses below those typically available in large cosmological simulations. The three different density regions available at higher resolution provide a better understanding of the effect of the local environment on halo concentration, known to be potentially important for small simulation boxes and small halo masses. Yet, we find the correction to be small in comparison with the scatter of halo concentrations. We conclude that zoom simulations, despite their limited representativity of the volume of the Universe, can be effectively used for the measurement of halo concentrations at least at the halo masses probed by our simulations. In any case, after a precise characterization of this effect, we develop a robust technique to extrapolate the concentration values found in zoom simulations to larger volumes with greater accuracy. Altogether, Lomonosov provides a measure of the concentration-mass relation in the halo mass range 107-1010 h-1 M⊙ with superb halo statistics. This work represents a first important step to measure halo concentrations at intermediate, yet vastly unexplored halo mass scales, down to the smallest ones. All Lomonosov data and files are public for community's use.

  20. High-energy particle production in solar flares (SEP, gamma-ray and neutron emissions). [solar energetic particles

    Science.gov (United States)

    Chupp, E. L.

    1987-01-01

    Electrons and ions, over a wide range of energies, are produced in association with solar flares. Solar energetic particles (SEPs), observed in space and near earth, consist of electrons and ions that range in energy from 10 keV to about 100 MeV and from 1 MeV to 20 GeV, respectively. SEPs are directly recorded by charged particle detectors, while X-ray, gamma-ray, and neutron detectors indicate the properties of the accelerated particles (electrons and ions) which have interacted in the solar atmosphere. A major problem of solar physics is to understand the relationship between these two groups of charged particles; in particular whether they are accelerated by the same mechanism. The paper reviews the physics of gamma-rays and neutron production in the solar atmosphere and the method by which properties of the primary charged particles produced in the solar flare can be deduced. Recent observations of energetic photons and neutrons in space and at the earth are used to present a current picture of the properties of impulsively flare accelerated electrons and ions. Some important properties discussed are time scale of production, composition, energy spectra, accelerator geometry. Particular attention is given to energetic particle production in the large flare on June 3, 1982.

  1. Production mechanism of negative pionlike particles in H2 gas discharge plasma

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1996-04-01

    Negative pionlike and muonlike particles are produced by an electron bunch and a positive ion bunch which are generated controllably from an electron beam and a gas. Physical characteristics of the negative pionlike particles are the same with those of negative pionlike particles extracted from the H 2 gas discharge. Thus, the production mechanism in the H 2 gas discharge is deduced. (author)

  2. Production and applications of neutrons using particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Chichester, David L. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2009-11-01

    Advances in neutron science have gone hand in hand with the development and of particle accelerators from the beginning of both fields of study. Early accelerator systems were developed simply to produce neutrons, allowing scientists to study their properties and how neutrons interact in matter, but people quickly realized that more tangible uses existed too. Today the diversity of applications for industrial accelerator-based neutron sources is high and so to is the actual number of instruments in daily use is high, and they serve important roles in the fields where they're used. This chapter presents a technical introduction to the different ways particle accelerators are used to produce neutrons, an historical overview of the early development of neutron-producing particle accelerators, a description of some current industrial accelerator systems, narratives of the fields where neutron-producing particle accelerators are used today, and comments on future trends in the industrial uses of neutron producing particle accelerators.

  3. Non-Gaussian halo assembly bias

    International Nuclear Information System (INIS)

    Reid, Beth A.; Verde, Licia; Dolag, Klaus; Matarrese, Sabino; Moscardini, Lauro

    2010-01-01

    The strong dependence of the large-scale dark matter halo bias on the (local) non-Gaussianity parameter, f NL , offers a promising avenue towards constraining primordial non-Gaussianity with large-scale structure surveys. In this paper, we present the first detection of the dependence of the non-Gaussian halo bias on halo formation history using N-body simulations. We also present an analytic derivation of the expected signal based on the extended Press-Schechter formalism. In excellent agreement with our analytic prediction, we find that the halo formation history-dependent contribution to the non-Gaussian halo bias (which we call non-Gaussian halo assembly bias) can be factorized in a form approximately independent of redshift and halo mass. The correction to the non-Gaussian halo bias due to the halo formation history can be as large as 100%, with a suppression of the signal for recently formed halos and enhancement for old halos. This could in principle be a problem for realistic galaxy surveys if observational selection effects were to pick galaxies occupying only recently formed halos. Current semi-analytic galaxy formation models, for example, imply an enhancement in the expected signal of ∼ 23% and ∼ 48% for galaxies at z = 1 selected by stellar mass and star formation rate, respectively

  4. Three Lectures on Multi-Particle Production in the Glasma

    International Nuclear Information System (INIS)

    Gelis, F.; Venugopalan, R.

    2006-01-01

    In the Color Glass Condensate (CGC) effective field theory, when two large sheets of Colored Glass collide, as in a central nucleus-nucleus collision, they form a strongly interacting, non-equilibrium state of matter called the Glasma. How Colored Glass shatters to form the Glasma, the properties of the Glasma, and the complex dynamics transforming the Glasma to a thermalized Quark Gluon Plasma (QGP) are questions of central interest in understanding the properties of the strongly interacting matter produced in heavy ion collisions. In the first of these lectures, we shall discuss how these questions may be addressed in the framework of particle production in a field theory with strong time dependent external sources. Albeit such field theories are non-perturbative even for arbitrarily weak coupling, moments of the multiplicity distribution can in principle be computed systematically in powers of the coupling constant. We will demonstrate that the average multiplicity can be (straightforwardly) computed to leading order in the coupling and (remarkably) to next-to-leading order as well. The latter are obtained from solutions of small fluctuation equations of motion with retarded boundary conditions. In the second lecture, we relate our formalism to results from previous 2+1 and 3+1 dimensional numerical simulations of the Glasma fields. The latter show clearly that the expanding Glasma is unstable; small fluctuations in the initial conditions grow exponentially with the square root of the proper time. Whether this explosive growth of small fluctuations leads to early thermalization in heavy ion collisions requires at present a better understanding of these fluctuations on the light cone. In the third and final lecture, motivated by recent work A. Bialas, M. Jezabek, Phys. Lett. B590, 233 (2004), we will discuss how the widely observed phenomenon of limiting fragmentation is realized in the CGC framework. (author)

  5. Beam losses and beam halos in accelerators for new energy sources

    International Nuclear Information System (INIS)

    Jameson, R.A.

    1995-01-01

    Large particle accelerators are proposed as drivers for new ways to produce electricity from nuclear fusion and fission reactions. The accelerators must be designed to deliver large particle beam currents to a target facility with very little beam spill along the accelerator itself, in order that accelerator maintenance can be accomplished without remote manipulators. Typically, particle loss is preceded by the formation of a tenuous halo of particles around the central beam core, caused by beam dynamics effects, often coupled with the slight imperfections inevitable in a practical design. If the halo becomes large enough, particles may be scraped off along the accelerator. The tolerance for beam spill in different applications is discussed, halo mechanisms and recent work to explore and understand their dynamics are reviewed, and possible directions for future investigation are outlined. 17 refs., 10 figs

  6. Softness of Nuclear Matter and the Production of Strange Particles in Neutron Stars

    Institute of Scientific and Technical Information of China (English)

    陈伟; 文德华; 刘良钢

    2003-01-01

    In the various models, we study the influences of the softness of nuclear matter, the vacuum fluctuation ofnucleons and σ mesons on the production of strange particles in neutron stars. Wefind that the stiffer the nuclear matter is, the more easily the strange particles is produced in neutron stars. The vacuum fluctuation of nucleons has large effect on strange particle production while that of σ meson has little effect on it.

  7. STIMULATION OF OXIDANT PRODUCTION IN ALVEOLAR MACROPHAGES BY POLLUTANT AND LATEX PARTICLES

    Science.gov (United States)

    Air pollutant dusts as well as chemically defined particles were examined for their activating effect on oxidant production (O2- and H2O2) in guinea pig alveolar macrophages (AM). Oxidant production was measured as chemiluminescence of albumin-bound luminol. All particles examine...

  8. The use of rotating electric arc for spherical particle production

    International Nuclear Information System (INIS)

    Bica, I.

    2000-01-01

    This work presents and experimental device designed to obtain spherical particles by mans of a rotating electric arc. A rotation frequency of the electric arc of 750 s''-1, a voltage of 50 V(dc) and a current of 100 A was used. The mass flow rate was 3 g.min''-1. Under these conditions particles of 15 to 20 μm in diameter were obtained. (Author) 8 refs

  9. Toward a Combined SAGE II-HALOE Aerosol Climatology: An Evaluation of HALOE Version 19 Stratospheric Aerosol Extinction Coefficient Observations

    Science.gov (United States)

    Thomason, L. W.

    2012-01-01

    Herein, the Halogen Occultation Experiment (HALOE) aerosol extinction coefficient data is evaluated in the low aerosol loading period after 1996 as the first necessary step in a process that will eventually allow the production of a combined HALOE/SAGE II (Stratospheric Aerosol and Gas Experiment) aerosol climatology of derived aerosol products including surface area density. Based on these analyses, it is demonstrated that HALOE's 3.46 microns is of good quality above 19 km and suitable for scientific applications above that altitude. However, it is increasingly suspect at lower altitudes and should not be used below 17 km under any circumstances after 1996. The 3.40 microns is biased by about 10% throughout the lower stratosphere due to the failure to clear NO2 but otherwise appears to be a high quality product down to 15 km. The 2.45 and 5.26 micron aerosol extinction coefficient measurements are clearly biased and should not be used for scientific applications after the most intense parts of the Pinatubo period. Many of the issues in the aerosol data appear to be related to either the failure to clear some interfering gas species or doing so poorly. For instance, it is clear that the 3.40micronaerosol extinction coefficient measurements can be improved through the inclusion of an NO2 correction and could, in fact, end up as the highest quality overall HALOE aerosol extinction coefficient measurement. It also appears that the 2.45 and 5.26 micron channels may be improved by updating the Upper Atmosphere Pilot Database which is used as a resource for the removal of gas species otherwise not available from direct HALOE measurements. Finally, a simple model to demonstrate the promise of mixed visible/infrared aerosol extinction coefficient ensembles for the retrieval of bulk aerosol properties demonstrates that a combined HALOE/SAGE II aerosol climatology is feasible and may represent a substantial improvement over independently derived data sets.

  10. Feasibility Study for Installing Machine in Production Line to Avoid Particle Contamination Based on CFD Simulation

    Science.gov (United States)

    Khaokom, Adisorn; Thongsri, Jatuporn

    2017-10-01

    Ventilation system inside production line for electronic component production needs to meet the factory standard. Because it can eliminate small particles which may cause of human or machine in production as well as it can distribute the circulating air temperature uniformly. CFD is used in this research in order to study the feasibility and plan for machine layout in production line before actual installation. The simulation shows the airflow in every area inside production line. From simulation with releasing the particles from human and machine is found that this ventilation system generates airflow that makes most particles float out of the machines and no particle downs to the conveyor, it results to contamination. In addition, the simulation also shows the range of 19-26 °C air temperature that meets the factory standard. The results of this research are the parts of the data to renovate the production line to get more efficiency and proper on the production.

  11. Implementation of a 3D halo neutral model in the TRANSP code and application to projected NSTX-U plasmas

    Science.gov (United States)

    Medley, S. S.; Liu, D.; Gorelenkova, M. V.; Heidbrink, W. W.; Stagner, L.

    2016-02-01

    A 3D halo neutral code developed at the Princeton Plasma Physics Laboratory and implemented for analysis using the TRANSP code is applied to projected National Spherical Torus eXperiment-Upgrade (NSTX-U plasmas). The legacy TRANSP code did not handle halo neutrals properly since they were distributed over the plasma volume rather than remaining in the vicinity of the neutral beam footprint as is actually the case. The 3D halo neutral code uses a ‘beam-in-a-box’ model that encompasses both injected beam neutrals and resulting halo neutrals. Upon deposition by charge exchange, a subset of the full, one-half and one-third beam energy components produce first generation halo neutrals that are tracked through successive generations until an ionization event occurs or the descendant halos exit the box. The 3D halo neutral model and neutral particle analyzer (NPA) simulator in the TRANSP code have been benchmarked with the Fast-Ion D-Alpha simulation (FIDAsim) code, which provides Monte Carlo simulations of beam neutral injection, attenuation, halo generation, halo spatial diffusion, and photoemission processes. When using the same atomic physics database, TRANSP and FIDAsim simulations achieve excellent agreement on the spatial profile and magnitude of beam and halo neutral densities and the NPA energy spectrum. The simulations show that the halo neutral density can be comparable to the beam neutral density. These halo neutrals can double the NPA flux, but they have minor effects on the NPA energy spectrum shape. The TRANSP and FIDAsim simulations also suggest that the magnitudes of beam and halo neutral densities are relatively sensitive to the choice of the atomic physics databases.

  12. Implementation of a 3D halo neutral model in the TRANSP code and application to projected NSTX-U plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Medley, S. S. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Liu, D. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy; Gorelenkova, M. V. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Heidbrink, W. W. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy; Stagner, L. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Univ. of California, Irvine, CA (United States). Dept. of Physics and Astronomy

    2016-01-12

    A 3D halo neutral code developed at the Princeton Plasma Physics Laboratory and implemented for analysis using the TRANSP code is applied to projected National Spherical Torus eXperiment-Upgrade (NSTX-U plasmas). The legacy TRANSP code did not handle halo neutrals properly since they were distributed over the plasma volume rather than remaining in the vicinity of the neutral beam footprint as is actually the case. The 3D halo neutral code uses a 'beam-in-a-box' model that encompasses both injected beam neutrals and resulting halo neutrals. Upon deposition by charge exchange, a subset of the full, one-half and one-third beam energy components produce first generation halo neutrals that are tracked through successive generations until an ionization event occurs or the descendant halos exit the box. The 3D halo neutral model and neutral particle analyzer (NPA) simulator in the TRANSP code have been benchmarked with the Fast-Ion D-Alpha simulation (FIDAsim) code, which provides Monte Carlo simulations of beam neutral injection, attenuation, halo generation, halo spatial diffusion, and photoemission processes. When using the same atomic physics database, TRANSP and FIDAsim simulations achieve excellent agreement on the spatial profile and magnitude of beam and halo neutral densities and the NPA energy spectrum. The simulations show that the halo neutral density can be comparable to the beam neutral density. These halo neutrals can double the NPA flux, but they have minor effects on the NPA energy spectrum shape. The TRANSP and FIDAsim simulations also suggest that the magnitudes of beam and halo neutral densities are relatively sensitive to the choice of the atomic physics databases.

  13. Electron Production and Collective Field Generation in Intense Particle Beams

    International Nuclear Information System (INIS)

    Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J; Covo, M K

    2006-01-01

    Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase in vacuum pressure, added heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation of present experience to significantly higher beam intensities is uncertain given the present level of understanding. With coordinated LDRD projects at LLNL and LBNL, we undertook a comprehensive R and D program including experiments, theory and simulations to better understand the phenomena, establish the essential parameters, and develop mitigating mechanisms. This LDRD project laid the essential groundwork for such a program. We developed insights into the essential processes, modeled the relevant physics, and implemented these models in computational production tools that can be used for self-consistent study of the effect on ion beams. We validated the models and tools through comparison with experimental data, including data from new diagnostics that we developed as part of this work and validated on the High-Current Experiment (HCX) at LBNL. We applied these models to High-Energy Physics (HEP) and other advanced accelerators. This project was highly successful, as evidenced by the two paragraphs above, and six paragraphs following that are taken from our 2003 proposal with minor editing that mostly consisted of changing the tense. Further benchmarks of outstanding performance are: we had 13 publications with 8 of them in refereed journals, our work was recognized by the accelerator and plasma physics communities by 8 invited papers and we have

  14. The effect of J2 on equatorial and halo orbits around a magnetic planet

    International Nuclear Information System (INIS)

    Inarrea, Manuel; Lanchares, Victor; Palacian, Jesus F.; Pascual, Ana I.; Pablo Salas, J.; Yanguas, Patricia

    2009-01-01

    We calculate equatorial and halo orbits around a non-spherical (both oblate and prolate) magnetic planet. It is known that circular equatorial and halo orbits exist for a dust grain orbiting a spherical magnetic planet. However, the frequency of the orbit is constrained by the charge-mass ratio of the particle. If the non-sphericity of the planet is taken into account this constraint is modified or, in some cases, it disappears.

  15. The effect of J{sub 2} on equatorial and halo orbits around a magnetic planet

    Energy Technology Data Exchange (ETDEWEB)

    Inarrea, Manuel [Universidad de la Rioja, Area de Fisica, 26006 Logrono (Spain); Lanchares, Victor [Dpto. de Matematicas y Computacion, CIEMUR: Centro de Investigacion en Informatica, Estadistica y Matematicas, Universidad de la Rioja, 26004 Logrono (Spain)], E-mail: vlancha@unirioja.es; Palacian, Jesus F. [Universidad Publica de Navarra, Departamento de Ingenieria Matematica e Informatica, 31006 Pamplona (Spain); Pascual, Ana I. [Dpto. de Matematicas y Computacion, CIEMUR: Centro de Investigacion en Informatica, Estadistica y Matematicas, Universidad de la Rioja, 26004 Logrono (Spain); Pablo Salas, J. [Universidad de la Rioja, Area de Fisica, 26006 Logrono (Spain); Yanguas, Patricia [Universidad Publica de Navarra, Departamento de Ingenieria Matematica e Informatica, 31006 Pamplona (Spain)

    2009-10-15

    We calculate equatorial and halo orbits around a non-spherical (both oblate and prolate) magnetic planet. It is known that circular equatorial and halo orbits exist for a dust grain orbiting a spherical magnetic planet. However, the frequency of the orbit is constrained by the charge-mass ratio of the particle. If the non-sphericity of the planet is taken into account this constraint is modified or, in some cases, it disappears.

  16. ULTRAVIOLET HALOS AROUND SPIRAL GALAXIES. I. MORPHOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Hodges-Kluck, Edmund; Cafmeyer, Julian; Bregman, Joel N., E-mail: hodgeskl@umich.edu [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-12-10

    We examine ultraviolet halos around a sample of highly inclined galaxies within 25 Mpc to measure their morphology and luminosity. Despite contamination from galactic light scattered into the wings of the point-spread function, we find that ultraviolet (UV) halos occur around each galaxy in our sample. Around most galaxies the halos form a thick, diffuse disk-like structure, but starburst galaxies with galactic superwinds have qualitatively different halos that are more extensive and have filamentary structure. The spatial coincidence of the UV halos above star-forming regions, the lack of consistent association with outflows or extraplanar ionized gas, and the strong correlation between the halo and galaxy UV luminosity suggest that the UV light is an extragalactic reflection nebula. UV halos may thus represent 10{sup 6}–10{sup 7} M {sub ⊙} of dust within 2–10 kpc of the disk, whose properties may change with height in starburst galaxies.

  17. The halo current in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Pautasso, G.; Giannone, L.; Gruber, O.; Herrmann, A.; Maraschek, M.; Schuhbeck, K.H.

    2011-01-01

    Due to the complexity of the phenomena involved, a self-consistent physical model for the prediction of the halo current is not available. Therefore the ITER specifications of the spatial distribution and evolution of the halo current rely on empirical assumptions. This paper presents the results of an extensive analysis of the halo current measured in ASDEX Upgrade with particular emphasis on the evolution of the halo region, on the magnitude and time history of the halo current, and on the structure and duration of its toroidal and poloidal asymmetries. The effective length of the poloidal path of the halo current in the vessel is found to be rather insensitive to plasma parameters. Large values of the toroidally averaged halo current are observed in both vertical displacement events and centred disruptions but last a small fraction of the current quench; they coincide typically with a large but short-lived MHD event.

  18. The halo current in ASDEX Upgrade

    Science.gov (United States)

    Pautasso, G.; Giannone, L.; Gruber, O.; Herrmann, A.; Maraschek, M.; Schuhbeck, K. H.; ASDEX Upgrade Team

    2011-04-01

    Due to the complexity of the phenomena involved, a self-consistent physical model for the prediction of the halo current is not available. Therefore the ITER specifications of the spatial distribution and evolution of the halo current rely on empirical assumptions. This paper presents the results of an extensive analysis of the halo current measured in ASDEX Upgrade with particular emphasis on the evolution of the halo region, on the magnitude and time history of the halo current, and on the structure and duration of its toroidal and poloidal asymmetries. The effective length of the poloidal path of the halo current in the vessel is found to be rather insensitive to plasma parameters. Large values of the toroidally averaged halo current are observed in both vertical displacement events and centred disruptions but last a small fraction of the current quench; they coincide typically with a large but short-lived MHD event.

  19. Brown dwarfs as dark galactic halos

    International Nuclear Information System (INIS)

    Adams, F.C.; Walker, T.P.

    1990-01-01

    The possibility that the dark matter in galactic halos can consist of brown dwarf stars is considered. The radiative signature for such halos consisting solely of brown dwarfs is calculated, and the allowed range of brown dwarf masses, the initial mass function (IMF), the stellar properties, and the density distribution of the galactic halo are discussed. The prediction emission from the halo is compared with existing observations. It is found that, for any IMF of brown dwarfs below the deuterium burning limit, brown dwarf halos are consistent with observations. Brown dwarf halos cannot, however, explain the recently observed near-IR background. It is shown that future satellite missions will either detect brown dwarf halos or place tight constraints on the allowed range of the IMF. 30 refs

  20. Cataract production in mice by heavy charged particles

    International Nuclear Information System (INIS)

    Ainsworth, E.H.; Jose, J.; Yang, V.V.; Barker, M.E.

    1981-03-01

    The cataractogenic effects of heavy charged particles have been evaluated in mice in relation to dose and ionization density (LET/sub infinity/). The study was undertaken due to the high potential for eye exposures to HZE particles among SPS personnel working in outer space. This has made it imperative that the relative biological effectiveness (RBE) in relation to LET/sub infinity/ for various particles be defined so that appropriate quality factors (Q) could be assigned for estimation of risk. Although mice and men differ in susceptibility to radiation-induced cataracts, the results from this project should assist in defining appropriate quality factors in relation to LET/sub infinity/, particle mass, charge, or velocity. Evaluation of results indicated that : (1) low single doses (5 to 20 rad) of iron ( 56 Fe) or argon ( 40 Ar) particles are cataractogenic at 11 to 18 months after irradiation; (2) onset and density of the opacification are dose related; (3) cataract density (grade) at 9, 11, 13, and 16 months after irradiation shows partial LET/sub infinity/-dependence; and (4) the severity of cataracts is reduced significantly when 417 rad of 60 Co gamma radiation is given in 24 weekly 17 rad fractions compared to giving this radiation as a single dose, but cataract severity is not reduced by fractionation of 12 C doses over 24 weeks

  1. Emanation of 232U and its radioactive daughter products from respirable size particles

    International Nuclear Information System (INIS)

    Cuddihy, R.G.; Griffith, W.C.; Hoover, M.D.; Kanapilly, G.M.; Stalnaker, N.D.

    1978-01-01

    This study is to develop a model for the emanation of 232 U and its radioactive daughter products from particles of Th-U fuel material. The radiation doses to internal organs following inhalation of these particles can only be calculated by knowing the rate of emanation of the daughters from particles in the lung and the subsequent excretion or translocation of the daughters to other organs. The emanation mechanisms are recoil of the daughter nuclei from the particle during alpha decay of the parent, diffusion of inert gas daughters from the particle and dissolution of the particle itself in biological fluids. Experiments to evaluate these mechanisms will involve ThO 2 and UO 2 particles in the size range 0.1 to 1.0 μm MMAD uniformly labeled with 232 U. The influence of the material temperature history on emanation will be investigated by heat treating particles at 600 and 1400 0 C

  2. Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

    Directory of Open Access Journals (Sweden)

    Toppi M.

    2016-01-01

    Full Text Available Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presented.

  3. Search for the H particle: Its production and weak decay

    International Nuclear Information System (INIS)

    Barnes, P.D.

    1991-01-01

    Jaffe has suggested that a six-quark state with the flavor content of two-lambda hyperons with all spins coupled to zero, the H particle, may be bound against strong decay. This particle has become the object of extensive discussion in the literature and of several experimental searches. We report here the present status of an investigation of the reaction: (Ξ-,d) atom → H + n in experiment E-813 at the BNL-AGS and describe plans for future running in 1992

  4. Inclusive neutral particle production in anti pp interactions at 22.4 GeV/c

    International Nuclear Information System (INIS)

    Boos, E.G.; Samojlov, V.V.; Takibaev, Zh.S.

    1978-01-01

    The results of an analysis of inclusive production of γ(πsup(0)), Ksub(s)ysup(0), Λ, anti Λ particles in anti pp interaction at 22.4 GeV/c are presented. The total and topological inclusive cross sections of neutral particles were obtained. The charged multiplicity dependences of the mean number of πsup(0), Ksup(0)/ anti Ksup(0), Λ/ anti Λ productions were studied. The mean number of Λ/ anti Λ particles decreases with increasing charged multiplicity. The KNO scaling hypothesis for πsup(0), Ksub(s)sup(0), Λ particles was confirmed

  5. Fission product behavior in HTGR fuel particles made from weak-acid resins

    International Nuclear Information System (INIS)

    Tiegs, T.N.; Henson, T.J.

    1979-04-01

    Fission product retention and behavior are of utmost importance in HTGR fuel particles. The present study concentrates on particles made from weak-acid resins, which can vary in composition from 100% UO 2 plus excess carbon to 100% UC 2 plus excess carbon. Five compositions were tested: UC 4 58 O 2 04 , UC 3 68 O 0 01 , UC 4 39 O 1 72 , UC 4 63 O 0 97 , and UC 4 14 O 1 53 . Metallographically sectioned particles were examined with a shielded electron microprobe. The distributions of the fission products were determined by monitoring characteristic x-ray lines while scanning the electron beam over the particle surface

  6. Production of slow particle in 1.7 AGeV 84Kr induced emulsion interaction

    International Nuclear Information System (INIS)

    Li Huiling; Zhang Donghai; Li Xueqin; Jia Huiming

    2008-01-01

    The production of slow particle in 1.7 AGeV 84 Kr induced emulsion interaction was studied. The experimental results show that the average multiplicity of black, grey and heavily ionized track particle increases with the increase of impact centrality and target size. The average multiplicity of grey track particle and heavily ionized track particle increases with the increase of the number of black track particle. The average multiplicity of heavily ionized track particle increases with the increase of the number of grey track particle, but average multiplicity of black track particle increases with the increase of the number of grey track particle and then saturated. The average multiplicity of grey track particle increases with the increase of the number of heavily ionized track particle, but average multiplicity of black track particle increases with the increase of the number of heavily ionized track particle and then saturated. Those experimental results can be well explained by using the nuclear impact geometry model. (authors)

  7. Systematic problems with using dark matter simulations to model stellar halos

    International Nuclear Information System (INIS)

    Bailin, Jeremy; Bell, Eric F.; Valluri, Monica; Stinson, Greg S.; Debattista, Victor P.; Couchman, H. M. P.; Wadsley, James

    2014-01-01

    The limits of available computing power have forced models for the structure of stellar halos to adopt one or both of the following simplifying assumptions: (1) stellar mass can be 'painted' onto dark matter (DM) particles in progenitor satellites; (2) pure DM simulations that do not form a luminous galaxy can be used. We estimate the magnitude of the systematic errors introduced by these assumptions using a controlled set of stellar halo models where we independently vary whether we look at star particles or painted DM particles, and whether we use a simulation in which a baryonic disk galaxy forms or a matching pure DM simulation that does not form a baryonic disk. We find that the 'painting' simplification reduces the halo concentration and internal structure, predominantly because painted DM particles have different kinematics from star particles even when both are buried deep in the potential well of the satellite. The simplification of using pure DM simulations reduces the concentration further, but increases the internal structure, and results in a more prolate stellar halo. These differences can be a factor of 1.5-7 in concentration (as measured by the half-mass radius) and 2-7 in internal density structure. Given this level of systematic uncertainty, one should be wary of overinterpreting differences between observations and the current generation of stellar halo models based on DM-only simulations when such differences are less than an order of magnitude.

  8. Helicity-flip in particle production on nuclei

    International Nuclear Information System (INIS)

    Faeldt, G.

    1977-01-01

    Coherent nuclear production processes are generally analyzed assuming helicity conserving production amplitudes. In view of the uncertainties of the actual helicity structure this could be a dangerous assumption. It is shown that helicity-flip contributions might be part of the explanation of the small effective (pππ)-nucleon cross sections observed in coherent production. (Auth.)

  9. THE SCALING RELATIONS AND THE FUNDAMENTAL PLANE FOR RADIO HALOS AND RELICS OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Yuan, Z. S.; Han, J. L.; Wen, Z. L.

    2015-01-01

    Diffuse radio emission in galaxy clusters is known to be related to cluster mass and cluster dynamical state. We collect the observed fluxes of radio halos, relics, and mini-halos for a sample of galaxy clusters from the literature, and calculate their radio powers. We then obtain the values of cluster mass or mass proxies from previous observations, and also obtain the various dynamical parameters of these galaxy clusters from optical and X-ray data. The radio powers of relics, halos, and mini-halos are correlated with the cluster masses or mass proxies, as found by previous authors, while the correlations concerning giant radio halos are in general the strongest. We found that the inclusion of dynamical parameters as the third dimension can significantly reduce the data scatter for the scaling relations, especially for radio halos. We therefore conclude that the substructures in X-ray images of galaxy clusters and the irregular distributions of optical brightness of member galaxies can be used to quantitatively characterize the shock waves and turbulence in the intracluster medium responsible for re-accelerating particles to generate the observed diffuse radio emission. The power of radio halos and relics is correlated with cluster mass proxies and dynamical parameters in the form of a fundamental plane

  10. Galaxy and Mass Assembly (GAMA): halo formation times and halo assembly bias on the cosmic web

    Science.gov (United States)

    Tojeiro, Rita; Eardley, Elizabeth; Peacock, John A.; Norberg, Peder; Alpaslan, Mehmet; Driver, Simon P.; Henriques, Bruno; Hopkins, Andrew M.; Kafle, Prajwal R.; Robotham, Aaron S. G.; Thomas, Peter; Tonini, Chiara; Wild, Vivienne

    2017-09-01

    We present evidence for halo assembly bias as a function of geometric environment (GE). By classifying Galaxy and Mass Assembly (GAMA) galaxy groups as residing in voids, sheets, filaments or knots using a tidal tensor method, we find that low-mass haloes that reside in knots are older than haloes of the same mass that reside in voids. This result provides direct support to theories that link strong halo tidal interactions with halo assembly times. The trend with GE is reversed at large halo mass, with haloes in knots being younger than haloes of the same mass in voids. We find a clear signal of halo downsizing - more massive haloes host galaxies that assembled their stars earlier. This overall trend holds independently of GE. We support our analysis with an in-depth exploration of the L-Galaxies semi-analytic model, used here to correlate several galaxy properties with three different definitions of halo formation time. We find a complex relationship between halo formation time and galaxy properties, with significant scatter. We confirm that stellar mass to halo mass ratio, specific star formation rate (SFR) and mass-weighed age are reasonable proxies of halo formation time, especially at low halo masses. Instantaneous SFR is a poor indicator at all halo masses. Using the same semi-analytic model, we create mock spectral observations using complex star formation and chemical enrichment histories, which approximately mimic GAMA's typical signal-to-noise ratio and wavelength range. We use these mocks to assert how well potential proxies of halo formation time may be recovered from GAMA-like spectroscopic data.

  11. Production of neutrinos and neutrino-like particles in proton-nucleus interactions

    International Nuclear Information System (INIS)

    Dishaw, J.P.

    1979-03-01

    An experimental search was performed to look for the direct production of neutrinos or neutrino-like particles, i.e., neutral particles which interact weakly with hadrons, in proton-nucleus interactions at 400 GeV incident proton energy. Possible sources of such particles include the semi-leptonic decay of new heavy particles such as charm, and the direct production of a light neutral Higgs particle such as the axion. The production of these particles has been inferred in this experiment by energy nonconservation in the collision of a proton with an iron nucleus. The total visible energy of the interaction was measured using a sampling ionization calorimeter. After correcting for beam intensity effects and cutting the data to eliminate systematic effects in the measurement, the final resolution of the calorimeter was 3.51% and increased with decreasing incident beam energy with a square root dependence on the beam energy. Energy nonconservation in the data is manifest as a non-Gaussian distribution on the low side of the calorimeter measured energy. Model calculations yield the fraction of events expected in this non-Gaussian behavior for the various sources of neutrinos or neutrino-like particles. A maximum likelihood fit to the data with the theoretical fraction of events expected yields the 95% confidence level production cross section upper limit values. The upper limits for general production of neutrino-like particles for various parameterizations of the production cross section are presented. The following specific upper limits have been established: charm particle production -3 times the π 0 production cross section. 144 references

  12. Search for additional muons in hadronic production of J/psi particles

    International Nuclear Information System (INIS)

    Anderson, K.J.; Coleman, R.N.; Karhi, K.P.; Newman, C.B.; Pilcher, J.E.; Rosenberg, E.I.; Thaler, J.J.; Hogan, G.E.; McDonald, K.T.; Sanders, G.H.; Smith, A.J.S.

    1980-01-01

    A sample of J/psi → μ + μ - decays produced by a 225-GeV/c π - beam on nuclear targets has been analyzed for extra muons. Muons observed in coincidence with J/psi production could indicate either the production of charmed particles or the production of pairs of J/psi particles. We find 90% confidence limits of sigma/sub J/DD-bar/sigma/sub J/<0.016 for associated charm production and sigma/sub J/J/sigma/sub J/<0.005 for the production of J/psi pairs

  13. Electroweak contributions to SUSY particle production processes at the LHC

    International Nuclear Information System (INIS)

    Mirabella, Edoardo

    2009-01-01

    In this thesis we have computed the electroweak contributions of O(α s α), O(α 2 ) and O(α s 2 ) to three different classes of processes leading to the hadronic production of the SUSY partners of quarks and gluons, i.e. squarks and gluinos. The theoretical framework is the Minimal Supersymmetric extension of the Standard Model, the MSSM. The three processes are gluino pair production, diagonal squark-antisquark and associated squark-gluino production.

  14. Neutral strange particle production in deep inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-04-01

    This paper presents measurements of K 0 and Λ production in neutral current, deep inelastic scattering of 26.7 GeV electrons and 820 GeV protons in the kinematic range 10 2 2 , 0.0003 0 and Λ production are determined for transverse momenta p T >0.5 GeV and pseudorapidities vertical stroke ηvertical stroke + e - experiments. The production properties of K 0 's in events with and without a large rapidity gap are compared. Within the present statistics no indication for different K 0 production properties between diffractive and non-diffractive events is observed. (orig.)

  15. Systematics of Charged Particle Production in Heavy-Ion Collisions with the PHOBOS Detector at Rhic

    Science.gov (United States)

    Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2002-03-01

    The multiplicity of charged particles produced in Au+Au collisions as a function of energy, centrality, rapidity and azimuthal angle has been measured with the PHOBOS detector at RHIC. These results contribute to our understanding of the initial state of heavy ion collisions and provide a means to compare basic features of particle production in nuclear collisions with more elementary systems.

  16. Sum rule limitations of kinetic particle-production models

    International Nuclear Information System (INIS)

    Knoll, J.; CEA Centre d'Etudes Nucleaires de Grenoble, 38; Guet, C.

    1988-04-01

    Photoproduction and absorption sum rules generalized to systems at finite temperature provide a stringent check on the validity of kinetic models for the production of hard photons in intermediate energy nuclear collisions. We inspect such models for the case of nuclear matter at finite temperature employed in a kinetic regime which copes those encountered in energetic nuclear collisions, and find photon production rates which significantly exceed the limits imposed by the sum rule even under favourable concession. This suggests that coherence effects are quite important and the production of photons cannot be considered as an incoherent addition of individual NNγ production processes. The deficiencies of present kinetic models may also apply for the production of probes such as the pion which do not couple perturbatively to the nuclear currents. (orig.)

  17. What to expect from dynamical modelling of galactic haloes - II. The spherical Jeans equation

    Science.gov (United States)

    Wang, Wenting; Han, Jiaxin; Cole, Shaun; More, Surhud; Frenk, Carlos; Schaller, Matthieu

    2018-06-01

    The spherical Jeans equation (SJE) is widely used in dynamical modelling of the Milky Way (MW) halo potential. We use haloes and galaxies from the cosmological Millennium-II simulation and hydrodynamical APOSTLE (A Project of Simulations of The Local Environment) simulations to investigate the performance of the SJE in recovering the underlying mass profiles of MW mass haloes. The best-fitting halo mass and concentration parameters scatter by 25 per cent and 40 per cent around their input values, respectively, when dark matter particles are used as tracers. This scatter becomes as large as a factor of 3 when using star particles instead. This is significantly larger than the estimated statistical uncertainty associated with the use of the SJE. The existence of correlated phase-space structures that violate the steady-state assumption of the SJE as well as non-spherical geometries is the principal source of the scatter. Binary haloes show larger scatter because they are more aspherical in shape and have a more perturbed dynamical state. Our results confirm that the number of independent phase-space structures sets an intrinsic limiting precision on dynamical inferences based on the steady-state assumption. Modelling with a radius-independent velocity anisotropy, or using tracers within a limited outer radius, result in significantly larger scatter, but the ensemble-averaged measurement over the whole halo sample is approximately unbiased.

  18. THE ROCKSTAR PHASE-SPACE TEMPORAL HALO FINDER AND THE VELOCITY OFFSETS OF CLUSTER CORES

    International Nuclear Information System (INIS)

    Behroozi, Peter S.; Wechsler, Risa H.; Wu, Hao-Yi

    2013-01-01

    We present a new algorithm for identifying dark matter halos, substructure, and tidal features. The approach is based on adaptive hierarchical refinement of friends-of-friends groups in six phase-space dimensions and one time dimension, which allows for robust (grid-independent, shape-independent, and noise-resilient) tracking of substructure; as such, it is named ROCKSTAR (Robust Overdensity Calculation using K-Space Topologically Adaptive Refinement). Our method is massively parallel (up to 10 5 CPUs) and runs on the largest current simulations (>10 10 particles) with high efficiency (10 CPU hours and 60 gigabytes of memory required per billion particles analyzed). A previous paper has shown ROCKSTAR to have excellent recovery of halo properties; we expand on these comparisons with more tests and higher-resolution simulations. We show a significant improvement in substructure recovery compared to several other halo finders and discuss the theoretical and practical limits of simulations in this regard. Finally, we present results that demonstrate conclusively that dark matter halo cores are not at rest relative to the halo bulk or substructure average velocities and have coherent velocity offsets across a wide range of halo masses and redshifts. For massive clusters, these offsets can be up to 350 km s –1 at z = 0 and even higher at high redshifts. Our implementation is publicly available at http://code.google.com/p/rockstar.

  19. Associated multiplicity of γ-particles in processes of lepton pair production on nuclei

    International Nuclear Information System (INIS)

    Gevorkyan, S.R.; Gulkanyan, H.R.; Vartanyan, V.A.

    1986-01-01

    An expression has been obtained for mean multiplicity of g-particles accompanying the process of deep-inelastic lepton pair production on nuclei. The expression allows one to get information on structure peculiarities of leading hadron in this process

  20. Production of charged Higgs particles in W+- decay

    International Nuclear Information System (INIS)

    Perez, M.A.; Soriano, M.A.

    1985-01-01

    It is pointed out that the recent detection by the UA1 collaboration of six candidates events for the semileptonic decays of the t quark would if confirmed exclude the existence of pointlike charged scalar particles H +- , includng charged Higgs bosons and charged hyperpions, with mass lower than the reported t-quark mass. This result comes from the fact that, if m/sub H/ + , which in turn implies that the branching ratio for the decay mode W +- →tb-bar(t-barb)→bb-barH +- can be as large as a few percent if the H +- -fermion conpling is proportional to the mass of the heaviest fermion available

  1. Constraints on the Galactic Halo Dark Matter from Fermi-LAT Diffuse Measurements

    Science.gov (United States)

    Ackermann, M.; Ajello, M.; Atwood, W. B.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; Bloom, E. D.; hide

    2012-01-01

    We have performed an analysis of the diffuse gamma-ray emission with the Fermi Large Area Telescope (LAT) in the Milky Way halo region, searching for a signal from dark matter annihilation or decay. In the absence of a robust dark matter signal, constraints are presented. We consider both gamma rays produced directly in the dark matter annihilation/decay and produced by inverse Compton scattering of the e+/e- produced in the annihilation/decay. Conservative limits are derived requiring that the dark matter signal does not exceed the observed diffuse gamma-ray emission. A second set of more stringent limits is derived based on modeling the foreground astrophysical diffuse emission using the GALPROP code. Uncertainties in the height of the diffusive cosmic-ray halo, the distribution of the cosmic-ray sources in the Galaxy, the index of the injection cosmic-ray electron spectrum, and the column density of the interstellar gas are taken into account using a profile likelihood formalism, while the parameters governing the cosmic-ray propagation have been derived from fits to local cosmic-ray data. The resulting limits impact the range of particle masses over which dark matter thermal production in the early universe is possible, and challenge the interpretation of the PAMELA/Fermi-LAT cosmic ray anomalies as the annihilation of dark matter.

  2. Optimization of physical factors affecting the production of thermo-stable organic solvent-tolerant protease from a newly isolated halo tolerant Bacillus subtilis strain Rand

    Directory of Open Access Journals (Sweden)

    Salleh Abu

    2009-04-01

    Full Text Available Abstract Background Many researchers have reported on the optimization of protease production; nevertheless, only a few have reported on the optimization of the production of organic solvent-tolerant proteases. Ironically, none has reported on thermostable organic solvent-tolerant protease to date. The aim of this study was to isolate the thermostable organic solvent-tolerant protease and identify the culture conditions which support its production. The bacteria of genus Bacillus are active producers of extra-cellular proteases, and the thermostability of enzyme production by Bacillus species has been well-studied by a number of researchers. In the present study, the Bacillus subtilis strain Rand was isolated from the contaminated soil found in Port Dickson, Malaysia. Results A thermostable organic solvent-tolerant protease producer had been identified as Bacillus subtilis strain Rand, based on the 16S rRNA analysis conducted, as well as the morphological characteristics and biochemical properties. The production of the thermostable organic solvent-tolerant protease was optimized by varying various physical culture conditions. Inoculation with 5.0% (v/v of (AB600 = 0.5 inoculum size, in a culture medium (pH 7.0 and incubated for 24 h at 37°C with 200 rpm shaking, was the best culture condition which resulted in the maximum growth and production of protease (444.7 U/ml; 4042.4 U/mg. The Rand protease was not only stable in the presence of organic solvents, but it also exhibited a higher activity than in the absence of organic solvent, except for pyridine which inhibited the protease activity. The enzyme retained 100, 99 and 80% of its initial activity, after the heat treatment for 30 min at 50, 55, and 60°C, respectively. Conclusion Strain Rand has been found to be able to secrete extra-cellular thermostable organic solvent-tolerant protease into the culture medium. The protease exhibited a remarkable stability towards temperature and organic

  3. Halo scale predictions of symmetron modified gravity

    Energy Technology Data Exchange (ETDEWEB)

    Clampitt, Joseph; Jain, Bhuvnesh; Khoury, Justin, E-mail: clampitt@sas.upenn.edu, E-mail: bjain@physics.upenn.edu, E-mail: jkhoury@sas.upenn.edu [Center for Particle Cosmology and Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd St., Philadelphia, PA 19104 (United States)

    2012-01-01

    We offer predictions of symmetron modified gravity in the neighborhood of realistic dark matter halos. The predictions for the fifth force are obtained by solving the nonlinear symmetron equation of motion in the spherical NFW approximation. In addition, we compare the three major known screening mechanisms: Vainshtein, Chameleon, and Symmetron around such dark matter halos, emphasizing the significant differences between them and highlighting observational tests which exploit these differences. Finally, we demonstrate the host halo environmental screening effect (''blanket screening'') on smaller satellite halos by solving for the modified forces around a density profile which is the sum of satellite and approximate host components.

  4. Electroweak contributions to SUSY particle production processes at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Mirabella, Edoardo

    2009-07-22

    In this thesis we have computed the electroweak contributions of O({alpha}{sub s}{alpha}), O({alpha}{sup 2}) and O({alpha}{sub s}{sup 2}) to three different classes of processes leading to the hadronic production of the SUSY partners of quarks and gluons, i.e. squarks and gluinos. The theoretical framework is the Minimal Supersymmetric extension of the Standard Model, the MSSM. The three processes are gluino pair production, diagonal squark-antisquark and associated squark-gluino production.

  5. Pair production of Dirac particles in a d + 1-dimensional noncommutative space-time

    Energy Technology Data Exchange (ETDEWEB)

    Ousmane Samary, Dine [Perimeter Institute for Theoretical Physics, Waterloo, ON (Canada); University of Abomey-Calavi, International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), Cotonou (Benin); N' Dolo, Emanonfi Elias; Hounkonnou, Mahouton Norbert [University of Abomey-Calavi, International Chair in Mathematical Physics and Applications (ICMPA-UNESCO Chair), Cotonou (Benin)

    2014-11-15

    This work addresses the computation of the probability of fermionic particle pair production in d + 1-dimensional noncommutative Moyal space. Using Seiberg-Witten maps, which establish relations between noncommutative and commutative field variables, up to the first order in the noncommutative parameter θ, we derive the probability density of vacuum-vacuum pair production of Dirac particles. The cases of constant electromagnetic, alternating time-dependent, and space-dependent electric fields are considered and discussed. (orig.)

  6. The landscape of particle production: results from PHOBOS

    Science.gov (United States)

    Steinberg, Peter; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Zhang, J.

    2004-08-01

    Recent results from the PHOBOS experiment at RHIC are presented, both from Au+Au collisions from the 2001 run and p+p and d+Au collisions from 2003. The centrality dependence of the total charged-particle multiplicity in p+p and d+Au shows features, such as Npart scaling and limiting fragmentation, similar to p+A collisions at lower energies. Multiparticle physics in Au+Au is found to be local in (pseudo)rapidity, both when observed by HBT correlations and by forward-backward pseudorapidity correlations. The shape of elliptic flow in Au+Au, measured over the full range of pseudorapidity, appears to have a very weak centrality dependence. Identified particle ratios in d+Au reactions show little difference between the shape of proton and anti-proton spectra, while the absolute yields show an approximate mT scaling. Finally, results on RdAu as a function of pseudorapidity show that this ratio decreases monotonically with η, even between 0.2 < η < 1.4.

  7. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers

    International Nuclear Information System (INIS)

    Fowler, W.B.

    1989-01-01

    Proton beams, from the 1GeV Cosmotron accelerator at Brookhaven, were used in the 1950s to produce strange particles. One big leap forward technologically was the development of the diffusion cloud chamber which made detecting particle tracks more accurate and sensitive. A large co-operative team worked on its development. By the mid 1950s enough tracks had been observed to show the associated production of strange particles. It was the same Brookhaven workers who developed the eighty-inch hydrogen bubble chamber which took the first photograph of the long predicted omega minus particle at the end of the decade. (UK)

  8. Particle production and targeting experience at the Brookhaven AGS

    International Nuclear Information System (INIS)

    Lazarus, D.M.

    1986-01-01

    Experience in production of secondary pions (neutrinos), kaons and antiprotons by 28.5 GeV/c protons incident on various target materials is given. The problems associated with various target materials with respect to target heating, physical degradation and in some cases, disintegration, are discussed. The effect of target length and production angle on secondary beam flux and optical quality will be illustrated by some incomplete but nonetheless informative data

  9. Numerical and analytical simulation of the production process of ZrO2 hollow particles

    Science.gov (United States)

    Safaei, Hadi; Emami, Mohsen Davazdah

    2017-12-01

    In this paper, the production process of hollow particles from the agglomerated particles is addressed analytically and numerically. The important parameters affecting this process, in particular, the initial porosity level of particles and the plasma gun types are investigated. The analytical model adopts a combination of quasi-steady thermal equilibrium and mechanical balance. In the analytical model, the possibility of a solid core existing in agglomerated particles is examined. In this model, a range of particle diameters (50μm ≤ D_{p0} ≤ 160 μ m) and various initial porosities ( 0.2 ≤ p ≤ 0.7) are considered. The numerical model employs the VOF technique for two-phase compressible flows. The production process of hollow particles from the agglomerated particles is simulated, considering an initial diameter of D_{p0} = 60 μm and initial porosity of p = 0.3, p = 0.5, and p = 0.7. Simulation results of the analytical model indicate that the solid core diameter is independent of the initial porosity, whereas the thickness of the particle shell strongly depends on the initial porosity. In both models, a hollow particle may hardly develop at small initial porosity values ( p disintegrates at high initial porosity values ( p > 0.6.

  10. Neutral strange particle production in antineutrino-neon charged current interactions

    Science.gov (United States)

    Willocq, S.; Marage, P.; Aderholz, M.; Allport, P.; Baton, J. P.; Berggren, M.; Clayton, E. F.; Cooper-Sarkar, A. M.; Erriquez, O.; Faulkner, P. J. W.; Guy, J.; Hulth, P. O.; Jones, G. T.; Mobayyen, M. M.; Morrison, D. R. O.; Neveu, M.; O'Neale, S.; Sacton, J.; Sansum, R. A.; Varvell, K.; Venus, W.; Wells, J.; Wittek, W.

    1992-06-01

    Neutral strange particle production inbar v Ne charged current interactions is studied using the bubble chamber BEBC, exposed to the CERN SPS antineutrino wide band beam. From a sample of 1191 neutral strange particles, the inclusive production rates are determined to be (15.7±0.8)% for K 0 mesons, (8.2±0.5)% for Λ, (0.4±0.2)% forbar Λ and (0.6±0.3)% for Σ0 hyperons. The inclusive production properties of K 0 mesons and Λ hyperons are investigated. The Λ hyperons are found to be polarized in the production plane.

  11. Rutile nanopowders for pigment production: Formation mechanism and particle size prediction

    Science.gov (United States)

    Zhang, Wu; Tang, Hongxin

    2018-01-01

    Formation mechanism and particle size prediction of rutile nanoparticles for pigment production were investigated. Anatase nanoparticles were observed by oriented attachment with parallel lattice fringe spaces of 0.2419 nm. Upon increasing the calcination temperature, the (1 1 0) plane of rutile was gradually observed, suggesting that the anatase (1 0 3) planes undergo internal structural rearrangement of oxygen and titanium ions into rutile phase due to ionic diffusion. Backpropagation neural network was used to predict particle size of rutile nanopowders, the prediction errors were all smaller than 2%, providing an efficient method to control particle size in pigment production.

  12. Semiclassical description of soliton-antisoliton pair production in particle collisions

    Energy Technology Data Exchange (ETDEWEB)

    Demidov, S.V.; Levkov, D.G. [Institute for Nuclear Research of the Russian Academy of Sciences,60th October Anniversary prospect 7a, Moscow 117312 (Russian Federation)

    2015-11-10

    We develop a consistent semiclassical method to calculate the probability of topological soliton-antisoliton pair production in collisions of elementary particles. In our method one adds an auxiliary external field pulling the soliton and antisoliton in the opposite directions. This transforms the original scattering process into a Schwinger pair creation of the solitons induced by the particle collision. One describes the Schwinger process semiclassically and recovers the original scattering probability in the limit of vanishing external field. We illustrate the method in (1+1)-dimensional scalar field model where the suppression exponents of soliton-antisoliton production in the multiparticle and two-particle collisions are computed numerically.

  13. Lepton pair production in deep inelastic scattering of polarized particles

    International Nuclear Information System (INIS)

    Hongan, P.; Danhua, Q.

    1981-08-01

    Using the leading order nucleon density function of QCD, we have calculated the differential cross sections and the helicity asymmetries Asub(L)(M 2 ) associated with definite initial helicity states in e(μ)+P→e(μ)+γsup(*), Z 0 +X→e(μ)+ll-bar+X at two energy ranges. The differential cross sections are too small to measure, but the integrated helicity asymmetry may be a measurable quantity which could be a clear test about the existence of Z 0 particle. We also show that the contributions of LPP where γsup(*),Z 0 radiated from e(μ) lepton lines are important when lepton pair mass M < or approx. 5 GeV., but becomes tiny as M is approximately equal to Msub(Z). (author)

  14. Recent results on new particle production at SPEAR

    International Nuclear Information System (INIS)

    Schwitters, R.

    1977-08-01

    Evidence for and properties of the charmed mesons D 0 , D/sup +-/, and their excited states is considered. Some very recent results on the structure of R, the ratio of the total cross section for hadron production by e + e - annihilation to the point-like muon pair cross section, in the center-of-mass energy region near 4 GeV are discussed. Evidence for D states, mass, spin, mixing, production cross sections, decay properties, and the observation of the psi (3772) are discussed. 38 references

  15. Analytic modeling of axisymmetric disruption halo currents

    International Nuclear Information System (INIS)

    Humphreys, D.A.; Kellman, A.G.

    1999-01-01

    Currents which can flow in plasma facing components during disruptions pose a challenge to the design of next generation tokamaks. Induced toroidal eddy currents and both induced and conducted poloidal ''halo'' currents can produce design-limiting electromagnetic loads. While induction of toroidal and poloidal currents in passive structures is a well-understood phenomenon, the driving terms and scalings for poloidal currents flowing on open field lines during disruptions are less well established. A model of halo current evolution is presented in which the current is induced in the halo by decay of the plasma current and change in enclosed toroidal flux while being convected into the halo from the core by plasma motion. Fundamental physical processes and scalings are described in a simplified analytic version of the model. The peak axisymmetric halo current is found to depend on halo and core plasma characteristics during the current quench, including machine and plasma dimensions, resistivities, safety factor, and vertical stability growth rate. Two extreme regimes in poloidal halo current amplitude are identified depending on the minimum halo safety factor reached during the disruption. A 'type I' disruption is characterized by a minimum safety factor that remains relatively high (typically 2 - 3, comparable to the predisruption safety factor), and a relatively low poloidal halo current. A 'type II' disruption is characterized by a minimum safety factor comparable to unity and a relatively high poloidal halo current. Model predictions for these two regimes are found to agree well with halo current measurements from vertical displacement event disruptions in DIII-D [T. S. Taylor, K. H. Burrell, D. R. Baker, G. L. Jackson, R. J. La Haye, M. A. Mahdavi, R. Prater, T. C. Simonen, and A. D. Turnbull, open-quotes Results from the DIII-D Scientific Research Program,close quotes in Proceedings of the 17th IAEA Fusion Energy Conference, Yokohama, 1998, to be published in

  16. THE PSEUDO-EVOLUTION OF HALO MASS

    International Nuclear Information System (INIS)

    Diemer, Benedikt; Kravtsov, Andrey V.; More, Surhud

    2013-01-01

    A dark matter halo is commonly defined as a spherical overdensity of matter with respect to a reference density, such as the critical density or the mean matter density of the universe. Such definitions can lead to a spurious pseudo-evolution of halo mass simply due to redshift evolution of the reference density, even if its physical density profile remains constant over time. We estimate the amount of such pseudo-evolution of mass between z = 1 and 0 for halos identified in a large N-body simulation, and show that it accounts for almost the entire mass evolution of the majority of halos with M 200ρ-bar ≲ 10 12 h -1 M ☉ and can be a significant fraction of the apparent mass growth even for cluster-sized halos. We estimate the magnitude of the pseudo-evolution assuming that halo density profiles remain static in physical coordinates, and show that this simple model predicts the pseudo-evolution of halos identified in numerical simulations to good accuracy, albeit with significant scatter. We discuss the impact of pseudo-evolution on the evolution of the halo mass function and show that the non-evolution of the low-mass end of the halo mass function is the result of a fortuitous cancellation between pseudo-evolution and the absorption of small halos into larger hosts. We also show that the evolution of the low-mass end of the concentration-mass relation observed in simulations is almost entirely due to the pseudo-evolution of mass. Finally, we discuss the implications of our results for the interpretation of the evolution of various scaling relations between the observable properties of galaxies and galaxy clusters and their halo masses.

  17. UARS Halogen Occultation Experiment (HALOE) Level 2 V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The HALOE home page on the WWW is http://haloe.gats-inc.com/home/index.php The Halogen Occultation Experiment (HALOE) on NASA's Upper Atmosphere Research Satellite...

  18. International conference on production of particles with new quantum numbers: Proceedings

    International Nuclear Information System (INIS)

    1976-01-01

    This report contains papers on the following topics: mechanisms of new particle production; the total cross section for e + e/sup /minus// → hadrons and its associated spectroscopy; recent results on the new particle states below 3.7 GeV produced in e + e/sup /minus// annihilations; new results on J//psi/ and /psi/' decays from DASP; excess muons and new results in /psi/ photoproduction; probing the new particles with hadron beams; properties of prompt leptons; muon production in hadron-hadron collisions; large transverse momentum photons from high energy proton proton collisions; dimuon and trimuon production in deep inelastic muon interactions; streamer chamber search for narrow hadrons with a muon-enriched trigger; threshold effects of new particle production by high energy neutrinos and antineutrinos; the observation of neutrino induced μ/sup /minus//e + events in the Fermilab bubble chamber; search for antineutrino induced μ + e/sup /minus// events; observation of muon-neutrino reactions producing a positron and a strange particle; observation of the reaction ν/sub μ/ + p → ν/sub μ/ + p; search for muonic pairs; strange particle production in neutrino interactions; neutral currents---the structure of the coupling; evidence for parity non-conservation in the weak neutral current; observation of elastic neutrino-proton scattering; threshold and other properties of U particle production in e + e/sup /minus// annihilation; anomalous muon production in e + e/sup /minus// collisions; electron production; strongly interacting heavy lepton; and /psi/'s without charm

  19. Particle production from nuclear targets and the structure of hadrons

    International Nuclear Information System (INIS)

    Bialas, A.

    Production processes from nuclear targets allow studying interactions of elementary hadronic constituents in nuclear matter. The information thus obtained on the structure of hadrons and on the properties of hadronic constituents is presented. Both soft (low momentum transfer) and hard (high momentum transfer) processes are discussed. (author)

  20. New results from PETRA on fragmentation and neutral particles production

    International Nuclear Information System (INIS)

    Fournier, Daniel.

    1981-10-01

    New results on the neutral component of jets are presented, including first measurements of π 0 production. Then a short review is made of the description of multihadronic events by first order QCD and fragmentation models, and some differences between the Lund and Feynman-Field models are analyzed

  1. The use of rotating electric are for spherical particle production

    Directory of Open Access Journals (Sweden)

    Bica, Ion

    2000-08-01

    Full Text Available This work presents an experimental device designed to obtain spherical partióles by means of a rotating electric are. A rotation frequency of the electric are of 750 s-1, a voltage of 50 V (dc and a current of 100 A was used. The mass flow rate was 3 g.min-1. Under these conditions particles of 15 to 20 μm in diameter were obtained.

    Este trabajo presenta la instalación experimental destinada a la obtención de partículas esféricas utilizando un arco eléctrico rotatorio. Para ello se utilizó una frecuencia de rotación del arco eléctrico de 750 s-1 a un voltaje del arco de 50 V (cc y una corriente de 100 A. La velocidad de flujo de materia fue de 3 g.min-1 obteniéndose partículas de diámetros comprendidos entre 15 y 20 μm.

  2. A mechanism for the production of ultrafine particles from concrete fracture.

    Science.gov (United States)

    Jabbour, Nassib; Rohan Jayaratne, E; Johnson, Graham R; Alroe, Joel; Uhde, Erik; Salthammer, Tunga; Cravigan, Luke; Faghihi, Ehsan Majd; Kumar, Prashant; Morawska, Lidia

    2017-03-01

    While the crushing of concrete gives rise to large quantities of coarse dust, it is not widely recognized that this process also emits significant quantities of ultrafine particles. These particles impact not just the environments within construction activities but those in entire urban areas. The origin of these ultrafine particles is uncertain, as existing theories do not support their production by mechanical processes. We propose a hypothesis for this observation based on the volatilisation of materials at the concrete fracture interface. The results from this study confirm that mechanical methods can produce ultrafine particles (UFP) from concrete, and that the particles are volatile. The ultrafine mode was only observed during concrete fracture, producing particle size distributions with average count median diameters of 27, 39 and 49 nm for the three tested concrete samples. Further volatility measurements found that the particles were highly volatile, showing between 60 and 95% reduction in the volume fraction remaining by 125 °C. An analysis of the volatile fraction remaining found that different volatile material is responsible for the production of particles between the samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. NLO corrections to the pair production of supersymmetric particles

    International Nuclear Information System (INIS)

    Obikhod, T.V.; Verbytskyy, A.A.

    2014-01-01

    The analysis of recent experimental data received from LHC (CMS) restricts the range of MSSM parameters. Using computer programs SOFTSUSY, SDECAY the mass spectrum and partial width of superpartners are calculated. With the help of computer program PROSPINO the calculations of the next-to-leading order (NLO) corrections to the production cross sections of superpartners are made. With the help of computer program PYTHIA the NLO corrections on differential distributions of p T and η for squarks and gluino are represented.

  4. Charged particle radioisotope production at Instituto de Engenharia Nuclear - IEN

    International Nuclear Information System (INIS)

    Lemos Junior, O.F.

    1992-05-01

    A variable energy isochronous cyclotron (CV-28) was installed in 1974 at the Instituto de Engenharia Nuclear in Rio de Janeiro, with the purpose, among others, of irradiating suitable targets to produce radioisotopes for medical diagnostic studies. This papers is an overview of the work done in the last two decades and reports the present status on the production of iodine-123 and gallium-67. (author)

  5. Halo star streams in the solar neighborhood

    NARCIS (Netherlands)

    Kepley, Amanda A.; Morrison, Heather L.; Helmi, Amina; Kinman, T. D.; Van Duyne, Jeffrey; Martin, John C.; Harding, Paul; Norris, John E.; Freeman, Kenneth C.

    2007-01-01

    We have assembled a sample of halo stars in the solar neighborhood to look for halo substructure in velocity and angular momentum space. Our sample ( 231 stars) includes red giants, RR Lyrae variable stars, and red horizontal branch stars within 2.5 kpc of the Sun with [Fe/H] less than -1.0. It was

  6. Studying dark matter haloes with weak lensing

    NARCIS (Netherlands)

    Velander, Malin Barbro Margareta

    2012-01-01

    Our Universe is comprised not only of normal matter but also of unknown components: dark matter and dark energy. This Thesis recounts studies of dark matter haloes, using a technique known as weak gravitational lensing, in order to learn more about the nature of these dark components. The haloes

  7. THE UNORTHODOX ORBITS OF SUBSTRUCTURE HALOS

    NARCIS (Netherlands)

    Ludlow, Aaron D.; Navarro, Julio F.; Springel, Volker; Jenkins, Adrian; Frenk, Carlos S.; Helmi, Amina

    2009-01-01

    We use a suite of cosmological N-body simulations to study the properties of substructure halos (subhalos) in galaxy-sized cold dark matter halos. We extend prior work on the subject by considering the whole population of subhalos physically associated with the main system. These are defined as

  8. Efimov effect in 2-neutron halo nuclei

    Indian Academy of Sciences (India)

    This paper presents an overview of our theoretical investigations in search of Efimov states in light 2-neutron halo nuclei. The calculations have been carried out within a three-body formalism, assuming a compact core and two valence neutrons forming the halo. The calculations provide strong evidence for the occurrence ...

  9. Beam halo formation from space-charge dominated beams in uniform focusing channels

    International Nuclear Information System (INIS)

    O'Connell, J.S.; Wangler, T.P.; Mills, R.S.; Crandall, K.R.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which results in a 2-component beam consisting of an inner core and an outer halo. The halo is very prominent in mismatched beams, and the potential for accelerator activation is of concern for a next generation of cw, high-power proton linacs that could be applied for intense neutron generators to process nuclear materials. We present new results about beam halo and the evolution of space-charge dominated beams from multiparticle simulation of initial laminar beams in a uniform linear focusing channel, and from a model consisting of single particle interactions with a uniform-density beam core. We study the energy gain from particle interactions with the space-charge field of the core, and we identify the resonant characteristic of this interaction as the basic cause of the separation of the beam into the two components. We identify three different particle-trajectory types, and we suggest that one of these types may lead to continuous halo growth, even after the halo is removed by collimators

  10. Applied metrology in the production of superconducting model magnets for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Ferradas Troitino, Jose [CERN; Bestmann, Patrick [CERN; Bourcey, Nicolas [CERN; Carlon Zurita, Alejandro [CERN; Cavanna, Eugenio [ASG Supercond., Genova; Ferracin, Paolo [CERN; Ferradas Troitino, Salvador [CERN; Holik, Eddie Frank [Fermilab; Izquierdo Bermudez, Susana [CERN; Lackner, Friedrich [CERN; Löffler, Christian [CERN; Maury, Gregory [CERN; Perez, Juan Carlos [CERN; Savary, Frederic [CERN; Semeraro, Michela [CERN; Vallone, Giorgio [CERN

    2017-12-22

    The production of superconducting magnets for particle accelerators involves high precision assemblies and tight tolerances, in order to achieve the requirements for their appropriate performance. It is therefore essential to have a strict control and traceability over the geometry of each component of the system, and also to be able to compensate possible inherent deviations coming from the production process.

  11. The production of charmed particles in high-energy 16O-emulsion central interactions

    International Nuclear Information System (INIS)

    Aoki, S.; Hoshino, K.; Kitamura, H.; Kobayashi, M.; Kodama, K.; Miyanishi, M.; Nakamura, K.; Nakamura, M.; Nakanishi, S.; Niu, K.; Niwa, K.; Nomura, M.; Tajima, H.; Tsukagoshi, K.; Mazzoni, M.A.; Poulard, G.; Meddi, F.; Rosa, G.; Muciaccia, M.T.; Simone, S.; Nakazawa, K.; Tasaka, S.; Sato, Y.

    1989-01-01

    The production of charmed particles has been detected in 200 GeV per nucleon 16 O-emulsion central interactions. Their production cross section in elementary nucleon-nucleon processes has been estimated to be σ charm =[14.1±9.3(stat.) -8.4 +5.6 (syst.)]μb. (orig.)

  12. Halo formation in three-dimensional bunches

    International Nuclear Information System (INIS)

    Gluckstern, R.L.; Fedotov, A.V.; Kurennoy, S.; Ryne, R.

    1998-01-01

    We have constructed, analytically and numerically, a class of self-consistent six-dimensional (6D) phase space stationary distributions. Stationary distributions allow us to study the halo development mechanism without it being obscured by beam redistribution and its effect on halo formation. The beam is then mismatched longitudinally and/or transversely, and we explore the formation of longitudinal and transverse halos in 3D axisymmetric beam bunches. We find that the longitudinal halo forms first for comparable longitudinal and transverse mismatches because the longitudinal tune depression is more severe than the transverse one for elongated bunches. Of particular importance is the result that, due to the coupling between longitudinal and transverse motion, a longitudinal or transverse halo is observed for a mismatch less than 10% if the mismatch in the other plane is large. copyright 1998 The American Physical Society

  13. Imbalance in the Local Galactic halo?

    International Nuclear Information System (INIS)

    Croswell, K.; Latham, D.W.; Carney, B.W.; North Carolina Univ., Chapel Hill)

    1987-01-01

    In a kinematically biased sample of 119 single halo stars, 65 percent of the stars are traveling away from the plane of the Galaxy. Halo spectroscopic binaries do not show this imbalance. Other kinematically biased halo surveys exhibit the same effect. Combining these samples with those of the authors' results in 223 halo stars, 63 percent of which are heading away from the plane of the Galaxy. The probability that the first result could be obtained from a symmetric w velocity distribution is 0.2 percent; the probability that the second result could be so obtained is 0.02 percent. Single halo stars traveling away from the disk appear to have a larger w velocity dispersion than those traveling toward it. Selection effects are analyzed and rejected as the cause of the observed asymmetry. Possible mechanisms for producing the imbalance are discussed, but each has serious difficulties accounting for the observations. 28 references

  14. Direct search for pair production of heavy stable charged particles in Z decays

    International Nuclear Information System (INIS)

    Soderstrom, E.; McKenna, J.A.; Abrams, G.S.; Adolphsen, C.E.; Averill, D.; Ballam, J.; Barish, B.C.; Barklow, T.; Barnett, B.A.; Bartelt, J.; Bethke, S.; Blockus, D.; Bonvicini, G.; Boyarski, A.; Brabson, B.; Breakstone, A.; Bulos, F.; Burchat, P.R.; Burke, D.L.; Cence, R.J.; Chapman, J.; Chmeissani, M.; Cords, D.; Coupal, D.P.; Dauncey, P.; DeStaebler, H.C.; Dorfan, D.E.; Dorfan, J.M.; Drewer, D.C.; Elia, R.; Feldman, G.J.; Fernandes, D.; Field, R.C.; Ford, W.T.; Fordham, C.; Frey, R.; Fujino, D.; Gan, K.K.; Gero, E.; Gidal, G.; Glanzman, T.; Goldhaber, G.; Gomez Cadenas, J.J.; Gratta, G.; Grindhammer, G.; Grosse-Wiesmann, P.; Hanson, G.; Harr, R.; Harral, B.; Harris, F.A.; Hawkes, C.M.; Hayes, K.; Hearty, C.; Heusch, C.A.; Hildreth, M.D.; Himel, T.; Hinshaw, D.A.; Hong, S.J.; Hutchinson, D.; Hylen, J.; Innes, W.R.; Jacobsen, R.G.; Jaros, J.A.; Jung, C.K.; Kadyk, J.A.; Kent, J.; King, M.; Koetke, D.S.; Komamiya, S.; Koska, W.; Kowalski, L.A.; Kozanecki, W.; Kral, J.F.; Kuhlen, M.; Labarga, L.; Lankford, A.J.; Larsen, R.R.; Le Diberder, F.; Levi, M.E.; Litke, A.M.; Lou, X.C.; Lueth, V.; Matthews, J.A.J.; Mattison, T.; Milliken, B.D.; Moffeit, K.C.; Munger, C.T.; Murray, W.N.; Nash, J.; Ogren, H.; O'Shaughnessy, K.F.; Parker, S.I.; Peck, C.; Perl, M.L.; Petradza, M.; Pitthan, R.; Porter, F.C.; Rankin, P.; Riles, K.; Rouse, F.R.; Rust, D.R.; Sadrozinski, H.F.W.; Schaad, M.W.; Schumm, B.A.; Seiden, A.; Smith, J.G.; Snyder, A.; Stoker, D.P.; Stroynowski, R.; Swartz, M.; Thun, R.; Trilling, G.H.; Van Kooten, R.; Voruganti, P.; Wagner, S.R.; Watson, S.; Weber, P.; Weinstein, A.J.; Weir, A.J.; Wicklund, E.; Woods, M.; Wu, D.Y.; Yurko, M.; Zaccardelli, C.; von Zanthie, C.

    1990-01-01

    A search for pair production of stable charged particles from Z decay has been performed with the Mark II detector at the SLAC Linear Collider. Particle masses are determined from momentum, ionization energy loss, and time-of-flight measurements. A limit excluding pair production of stable fourth-generation charged leptons and stable mirror fermions with masses between the muon mass and 36.3 GeV/c 2 is set at the 95% confidence level. Pair production of stable supersymmetric scalar leptons with masses between the muon mass and 32.6 GeV/c 2 is also excluded

  15. Impact-parameter dependence of the electromagnetic particle production in ultrarelativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Vidovic, M.; Greiner, M.; Best, C.; Soff, G.

    1992-08-01

    The cross section for the electromagentic production of different particles in heavy-ion collision is derived within the external field approach. The underlying assumption leading to the equivalent photon method is that the transverse components of the virtual photon momenta are small compared to their longitudinal components. Introducing polarized photon-fusion cross sections, it is possible to generalize the equivalent photon method to describe the impact- parameter dependence of the particle production. The impact- parameter dependent production of scalar and pseudoscalar (spin 0) bosons, charged (spin 0) boson pairs and fermion pairs is discussed in general. (orig.)

  16. Role of hydrotreating products in deposition of fine particles in reactors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.; Chung, K.; Gray, M.R. [University of Alberta, Edmonton, AB (Canada). Dept. of Chemical and Materials Engineering

    2001-06-11

    Hydrotreating reactions may affect the deposition of fine particles, which can eventually lead to reactor plugging. The deposition of fine particles from gas oil was measured in an internally recirculating reactor at 375{degree}C under hydrogen. H{sub 2}S from hydrodesulfurization would convert corrosion products to metal sulfides. Iron sulfide deposited rapidly in the packed bed because the mineral surface did not retain a stabilizing layer of asphaltenic material. Addition of water, to test the role of hydrodeoxygenation, doubled the deposition of clay particles by reducing the surface coating of organic material. Neither ammonia or quinoline had any effect on particle deposition, therefore, hydrodenitrogenation did not affect particle behavior. 16 refs., 4 figs., 3 tabs.

  17. Neutron secondary-particle production cross sections and their incorporation into Monte-Carlo transport codes

    International Nuclear Information System (INIS)

    Brenner, D.J.; Prael, R.E.; Little, R.C.

    1987-01-01

    Realistic simulations of the passage of fast neutrons through tissue require a large quantity of cross-sectional data. What are needed are differential (in particle type, energy and angle) cross sections. A computer code is described which produces such spectra for neutrons above ∼14 MeV incident on light nuclei such as carbon and oxygen. Comparisons have been made with experimental measurements of double-differential secondary charged-particle production on carbon and oxygen at energies from 27 to 60 MeV; they indicate that the model is adequate in this energy range. In order to utilize fully the results of these calculations, they should be incorporated into a neutron transport code. This requires defining a generalized format for describing charged-particle production, putting the calculated results in this format, interfacing the neutron transport code with these data, and charged-particle transport. The design and development of such a program is described. 13 refs., 3 figs

  18. Microfluidic Production of Alginate Hydrogel Particles for Antibody Encapsulation and Release.

    Science.gov (United States)

    Mazutis, Linas; Vasiliauskas, Remigijus; Weitz, David A

    2015-12-01

    Owing to their biocompatibility and reduced side effects, natural polymers represent an attractive choice for producing drug delivery systems. Despite few successful examples, however, the production of monodisperse biopolymer-based particles is often hindered by high viscosity of polymer fluids. In this work, we present a microfluidic approach for production of alginate-based particles carrying encapsulated antibodies. We use a triple-flow micro-device to induce hydrogel formation inside droplets before their collection off-chip. The fast mixing and gelation process produced alginate particles with a unique biconcave shape and dimensions of the mammalian cells. We show slow and fast dissolution of particles in different buffers and evaluate antibody release over time. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Universal behavior of charged particle production in heavy ion collisions at RHIC energies

    Science.gov (United States)

    Steinberg, Peter A.; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Phobos Collaboration

    2003-04-01

    The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at √ SNN = 19.6, 130 and 200 GeV. Two kinds of universal behavior are observed in charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/ overlinepp and e +e - data. / in nuclear collisions at high energy scales with √ s in a similar way as Nch in e +e - collisions and has a very weak centrality dependence. This feature may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

  20. Particle production at large transverse momentum and hard collision models

    International Nuclear Information System (INIS)

    Ranft, G.; Ranft, J.

    1977-04-01

    The majority of the presently available experimental data is consistent with hard scattering models. Therefore the hard scattering model seems to be well established. There is good evidence for jets in large transverse momentum reactions as predicted by these models. The overall picture is however not yet well enough understood. We mention only the empirical hard scattering cross section introduced in most of the models, the lack of a deep theoretical understanding of the interplay between quark confinement and jet production, and the fact that we are not yet able to discriminate conclusively between the many proposed hard scattering models. The status of different hard collision models discussed in this paper is summarized. (author)

  1. Halo control, beam matching, and new dynamical variables for beam distributions

    International Nuclear Information System (INIS)

    Lysenko, W.; Parsa, Z.

    1997-01-01

    We present the status of our work on physics models that relate release to the understanding and control of beam halo, which is a cause of particle loss in high power ion linear accelerators. We can minimize these particle losses, even in the presence of nonlinearities, by ensuring the beam is matched to high order. Our goal is to determine new dynamical variables that enable us to more directly solve for the evolution of the halo. We considered moments and several new variables, using a Lie-Poisson formulation whenever possible. Using symbolic techniques, we computed high-order matches and mode invariants (analogs of moment invariants) in the new variables. A promising new development developments is that of the variables we call weighted moments, which allow us to compute high-order nonlinear effects (like halos) while making use of well-developed existing results and computational techniques developed for studying first order effects. copyright 1997 American Institute of Physics

  2. Particle shedding from peristaltic pump tubing in biopharmaceutical drug product manufacturing.

    Science.gov (United States)

    Saller, Verena; Matilainen, Julia; Grauschopf, Ulla; Bechtold-Peters, Karoline; Mahler, Hanns-Christian; Friess, Wolfgang

    2015-04-01

    In a typical manufacturing setup for biopharmaceutical drug products, the fill and dosing pump is placed after the final sterile filtration unit in order to ensure adequate dispensing accuracy and avoid backpressure peaks. Given the sensitivity of protein molecules, peristaltic pumps are often preferred over piston pumps. However, particles may be shed from the silicone tubing employed. In this study, particle shedding and a potential turbidity increase during peristaltic pumping of water and buffer were investigated using three types of commercially available silicone tubing. In the recirculates, mainly particles of around 200 nm next to a very small fraction of particles in the lower micrometer range were found. Using 3D laser scanning microscopy, surface roughness of the inner tubing surface was found to be a determining factor for particle shedding from silicone tubing. As the propensity toward particle shedding varied between tubing types and also cannot be concluded from manufacturer's specifications, individual testing with the presented methods is recommended during tubing qualification. Choosing low abrasive tubing can help to further minimize the very low particle counts to be expected in pharmaceutical drug products. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  3. Hard scattering contribution to particle production in high energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Pareek, Pooja; Mishra, Aditya Nath; Sahoo, Pragati; Sahoo, Raghunath

    2014-01-01

    Global observables like the multiplicity of produced charged particles and transverse energy, are the key observables used to characterize the properties of the matter created in heavy-ion collisions. In order to study the dependence of the charged particle density on colliding system, center of mass energy and collision centrality, there have been measurements starting few GeV to TeV energies at LHC. There is a need to understand the particle production contribution coming from the QCD hard processes, which scale with number of binary nucleon-nucleon collisions, N coll and soft processes scaling with number of participant nucleons, N part

  4. Exotic particles at the LHC. Production via the Higgs portal and WIMP dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Hessler, Andre Georg

    2016-09-05

    This thesis addresses two different aspects of the search for Physics Beyond the Standard Model at the Large Hadron Collider (LHC). First, and motivated by the recent discovery of a new interaction mediated by the Higgs boson, we systematically analyze the impact of the Higgs interaction on the production of new particles at the LHC. Second, we investigate the collider signatures of long-lived particles decaying into leptons and invisible energy, and which are predicted to exist in a class of neutrino mass models with a weakly interacting dark matter particle.

  5. Combinative Particle Size Reduction Technologies for the Production of Drug Nanocrystals

    Directory of Open Access Journals (Sweden)

    Jaime Salazar

    2014-01-01

    Full Text Available Nanosizing is a suitable method to enhance the dissolution rate and therefore the bioavailability of poorly soluble drugs. The success of the particle size reduction processes depends on critical factors such as the employed technology, equipment, and drug physicochemical properties. High pressure homogenization and wet bead milling are standard comminution techniques that have been already employed to successfully formulate poorly soluble drugs and bring them to market. However, these techniques have limitations in their particle size reduction performance, such as long production times and the necessity of employing a micronized drug as the starting material. This review article discusses the development of combinative methods, such as the NANOEDGE, H 96, H 69, H 42, and CT technologies. These processes were developed to improve the particle size reduction effectiveness of the standard techniques. These novel technologies can combine bottom-up and/or top-down techniques in a two-step process. The combinative processes lead in general to improved particle size reduction effectiveness. Faster production of drug nanocrystals and smaller final mean particle sizes are among the main advantages. The combinative particle size reduction technologies are very useful formulation tools, and they will continue acquiring importance for the production of drug nanocrystals.

  6. SEPARATION OF FISCHER-TROPSCH WAX PRODUCTS FROM ULTRAFINE IRON CATALYST PARTICLES

    Energy Technology Data Exchange (ETDEWEB)

    James K. Neathery; Gary Jacobs; Burtron H. Davis

    2004-03-31

    In this reporting period, a fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of production since the reaction is highly exothermic. Consequently, heavy wax products must be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase FTS. The separation problem is further compounded by catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. Existing pilot-scale equipment was modified to include a filtration test apparatus. After undergoing an extensive plant shakedown period, filtration tests with cross-flow filter modules using simulant FTS wax slurry were conducted. The focus of these early tests was to find adequate mixtures of polyethylene wax to simulate FTS wax. Catalyst particle size analysis techniques were also developed. Initial analyses of the slurry and filter permeate particles will be used by the research team to design improved filter media and cleaning strategies.

  7. Evaluation of co-immobilized lactobacillus delbrueckii with porous particles for lactic acid production

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Seki, M.; Furusaki, S. [The University of Tokyo, Tokyo (Japan)

    1996-02-01

    Lactic acid production using co-immobilized L.defbrveckii with porous particles has been studied. The effect of co-immobilization with porous particles was verified by measuring the variations of both overall production rate of lactic acid and effective diffusion coefficient in the co-immobilized gel. The effective diffusion coefficient decreased with increasing cell concentration in the co-immobilized gel. However, in the high cell density regimes, the effective diffusion coefficient in co-immobilized gel was higher than that without co-immobilized porous particles. The optimal volume fraction of porous particles in the co-immobilizing gel beads leas estimated experimentally at about 10%(v/v). An approximately 30% increase of the overall production rate was obtained compared to the control culture. Mathematical analysis showed that by co-immobilizing cells with porous particles, the steady-state concentration profiles of proton and undissociated lactic acid changed favorably inside the gel beads. The result indicates that co-immobilization with porous particles is a useful method to improve fermentation efficiency in processes using immobilized cells. 19 refs., 8 figs.

  8. Particle Production in Two-Photon Collisions at Belle

    International Nuclear Information System (INIS)

    Nakazawa, Hideyuki

    2010-01-01

    Experimental study of η η production in two-photon collisions: The differential cross section for the process γ γ → η η has been measured in the kinematic range above the η η threshold, 1.096 GeV -1 data sample collected with the Belle detector at the KEKB e + e - collider. In the W range 1.1-2.0 GeV/c 2 we perform an analysis of resonance amplitudes for various partial waves; at higher energy we extract the contributions of χ cJ charmonia and compare the energy and angular dependence of the cross section with the predictions of theoretical models. Observation of η c (2S) in six-prong final states produced in two-photon collisions: We report the observation of η c (2S), produced in two-photon collisions, and decaying to the six-prong final states 3(π + π - ), K + K - 2(π + π - ), and K 0 S K + ππ + π - (including the charge-conjugate state). This analysis is based on a large data sample accumulated by the Belle experiment at the KEKB asymmetric-energy electron-positron collider. This is the first observation of decay modes of the η c (2S) other than K 0 S K + π - . (author)

  9. High velocity electromagnetic particle launcher for aerosol production studies

    International Nuclear Information System (INIS)

    Benson, D.A.; Rader, D.J.

    1986-05-01

    This report describes the development of a new device for study of metal combustion, breakup and production of aerosols in a high velocity environment. Metal wires are heated and electromagnetically launched with this device to produce molten metal droplets moving at velocities ranging up to about Mach 1. Such tests are presently intended to simulate the behavior of metal streamers ejected from a high-explosive detonation. A numerical model of the launcher performance in terms of sample properties, sample geometry and pulser electrical parameters is presented which can be used as a tool for design of specific test conditions. Results from several tests showing the range of sample velocities accessible with this device are described and compared with the model. Photographic measurements showing the behavior of tungsten and zirconium metal droplets are presented. Estimates of the Weber breakup and drag on the droplets, as well as calculations of the droplet trajectories, are described. Such studies may ultimately be useful in assessing environmental hazards in the handling and storage of devices containing metallic plutonium

  10. Strange particle production in ν and anti ν neon interactions

    International Nuclear Information System (INIS)

    Bosetti, P.; Fritze, P.; Graessler, H.; Schulte, R.; Schultze, K.; Mermikides, M.; Simopoulou, E.; Vayaki, A.; Butterworth, I.; Chima, J.S.; Clayton, E.; Iaselli, G.; Mobayyen, M.M.; Petrides, A.; Albajar, C.; Wells, J.

    1982-01-01

    The inclusive production of K 0 's and ν's has been investigated in neutrino and antineutrino interactions in BEBC, filled with a neon-hydrogen mixture. The inclusive rates for the 3083 (1022) ν(anti ν) induced charged current events are (23.0 +- 1.7)% ((21.9 +- 2.8)%) for K 0 's and (5.7 +- 0.7)% ((6.5 +- 1.2)%) for ν's. The general behaviour of the K 0 's and ν's is found to be similar to that in νp interactions and π + p interactions at lower . In the hadronic c.m.s. K 0 's are produced mostly forwards. ν's predominantly in the backward hemisphere. The data indicate that the K 0 's produced in anti ν interactions on average carry a larger fraction of the total available momentum than those in ν induced reactions. The dependences of the average transverse momentum on the variables Q 2 , W 2 and Bjorken x are presented. (orig.)

  11. Caustic ring model of the Milky Way halo

    International Nuclear Information System (INIS)

    Duffy, L. D.; Sikivie, P.

    2008-01-01

    We present a proposal for the full phase-space distribution of the Milky Way halo. The model is axially and reflection symmetric and its time evolution is self-similar. It describes the halo as a set of discrete dark matter flows with stated densities and velocity vectors everywhere. We first discuss the general conditions under which the time evolution of a cold collisionless self-gravitating fluid is self-similar, and show that symmetry is not necessary for self-similarity. When spherical symmetry is imposed, the model is the same as described by Fillmore and Goldreich, and by Bertschinger, twenty-three years ago. The spherically symmetric model depends on one dimensionless parameter ε and two dimensionful parameters. We set ε=0.3, a value consistent with the slope of the power spectrum of density perturbations on galactic scales. The dimensionful parameters are determined by the galactic rotation velocity (220 km/s) at the position of the Sun and by the age of the Galaxy (13.7 Gyr). The properties of the outer caustics are derived in the spherically symmetric model. The structure of the inner halo depends on the angular momentum distribution of the dark matter particles. We assume that distribution to be axial and reflection symmetric, and dominated by net overall rotation. The inner caustics are rings whose radii are determined in terms of a single additional parameter j max . We summarize the observational evidence in support of the model. The evidence is consistent with j max =0.18 in Concordance cosmology, equivalent to j max,old =0.26 in Einstein-de Sitter cosmology. We give formulas to estimate the flow densities and velocity vectors anywhere in the Milky Way halo. The properties of the first 40 flows at the location of the Earth are listed.

  12. Toward a combined SAGE II-HALOE aerosol climatology: an evaluation of HALOE version 19 stratospheric aerosol extinction coefficient observations

    Directory of Open Access Journals (Sweden)

    L. W. Thomason

    2012-09-01

    Full Text Available Herein, the Halogen Occultation Experiment (HALOE aerosol extinction coefficient data is evaluated in the low aerosol loading period after 1996 as the first necessary step in a process that will eventually allow the production of a combined HALOE/SAGE II (Stratospheric Aerosol and Gas Experiment aerosol climatology of derived aerosol products including surface area density. Based on these analyses, it is demonstrated that HALOE's 3.46 μm is of good quality above 19 km and suitable for scientific applications above that altitude. However, it is increasingly suspect at lower altitudes and should not be used below 17 km under any circumstances after 1996. The 3.40 μm is biased by about 10% throughout the lower stratosphere due to the failure to clear NO2 but otherwise appears to be a high quality product down to 15 km. The 2.45 and 5.26 μm aerosol extinction coefficient measurements are clearly biased and should not be used for scientific applications after the most intense parts of the Pinatubo period. Many of the issues in the aerosol data appear to be related to either the failure to clear some interfering gas species or doing so poorly. For instance, it is clear that the 3.40 μm aerosol extinction coefficient measurements can be improved through the inclusion of an NO2 correction and could, in fact, end up as the highest quality overall HALOE aerosol extinction coefficient measurement. It also appears that the 2.45 and 5.26 μm channels may be improved by updating the Upper Atmosphere Pilot Database which is used as a resource for the removal of gas species otherwise not available from direct HALOE measurements. Finally, a simple model to demonstrate the promise of mixed visible/infrared aerosol extinction coefficient ensembles for the retrieval of bulk aerosol properties demonstrates that a combined HALOE/SAGE II aerosol climatology is feasible and may represent a substantial improvement over independently derived

  13. Particle production at energies available at the CERN Large Hadron Collider within an evolutionary model

    Science.gov (United States)

    Sinyukov, Yu. M.; Shapoval, V. M.

    2018-06-01

    The particle yields and particle number ratios in Pb+Pb collisions at the CERN Large Hadron Collider (LHC) energy √{sN N}=2.76 TeV are described within the integrated hydrokinetic model (iHKM) at two different equations of state (EoS) for quark-gluon matter and the two corresponding hadronization temperatures T =165 MeV and T =156 MeV. The role of particle interactions at the final afterburner stage of the collision in the particle production is investigated by means of comparison of the results of full iHKM simulations with those where the annihilation and other inelastic processes (except for resonance decays) are switched off after hadronization/particlization, similarly as in the thermal models. An analysis supports the picture of continuous chemical freeze-out in the sense that the corrections to the sudden chemical freeze-out results, which arise because of the inelastic reactions at the subsequent evolution times, are noticeable and improve the description of particle number ratios. An important observation is that, although the particle number ratios with switched-off inelastic reactions are quite different at different particlization temperatures which are adopted for different equations of state to reproduce experimental data, the complete iHKM calculations bring very close results in both cases.

  14. Analysis of the beam halo in negative ion sources by using 3D3V PIC code

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, K., E-mail: kmiyamot@naruto-u.ac.jp [Naruto University of Education, 748 Nakashima, Takashima, Naruto-cho, Naruto-shi, Tokushima 772-8502 (Japan); Nishioka, S.; Goto, I.; Hatayama, A. [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Hanada, M.; Kojima, A.; Hiratsuka, J. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 319-0913 (Japan)

    2016-02-15

    The physical mechanism of the formation of the negative ion beam halo and the heat loads of the multi-stage acceleration grids are investigated with the 3D PIC (particle in cell) simulation. The following physical mechanism of the beam halo formation is verified: The beam core and the halo consist of the negative ions extracted from the center and the periphery of the meniscus, respectively. This difference of negative ion extraction location results in a geometrical aberration. Furthermore, it is shown that the heat loads on the first acceleration grid and the second acceleration grid are quantitatively improved compared with those for the 2D PIC simulation result.

  15. Halo assembly bias and the tidal anisotropy of the local halo environment

    Science.gov (United States)

    Paranjape, Aseem; Hahn, Oliver; Sheth, Ravi K.

    2018-05-01

    We study the role of the local tidal environment in determining the assembly bias of dark matter haloes. Previous results suggest that the anisotropy of a halo's environment (i.e. whether it lies in a filament or in a more isotropic region) can play a significant role in determining the eventual mass and age of the halo. We statistically isolate this effect, using correlations between the large-scale and small-scale environments of simulated haloes at z = 0 with masses between 1011.6 ≲ (m/h-1 M⊙) ≲ 1014.9. We probe the large-scale environment, using a novel halo-by-halo estimator of linear bias. For the small-scale environment, we identify a variable αR that captures the tidal anisotropy in a region of radius R = 4R200b around the halo and correlates strongly with halo bias at fixed mass. Segregating haloes by αR reveals two distinct populations. Haloes in highly isotropic local environments (αR ≲ 0.2) behave as expected from the simplest, spherically averaged analytical models of structure formation, showing a negative correlation between their concentration and large-scale bias at all masses. In contrast, haloes in anisotropic, filament-like environments (αR ≳ 0.5) tend to show a positive correlation between bias and concentration at any mass. Our multiscale analysis cleanly demonstrates how the overall assembly bias trend across halo mass emerges as an average over these different halo populations, and provides valuable insights towards building analytical models that correctly incorporate assembly bias. We also discuss potential implications for the nature and detectability of galaxy assembly bias.

  16. Improvement in retention of solid fission products in HTGR fuel particles by ceramic kernel additives

    International Nuclear Information System (INIS)

    Foerthmann, R.; Groos, E.; Gruebmeier, H.

    1975-08-01

    Increased requirements concerning the retention of long-lived solid fission products in fuel elements for use in advanced High Temperature Gas-cooled Reactors led to the development of coated particles with improved fission product retention of the kernel, which represent an alternative to silicon carbide-coated fuel particles. Two irradiation experiments have shown that the release of strontium, barium, and caesium from pyrocarbon-coated particles can be reduced by orders of magnitude if the oxide kernel contains alumina-silica additives. It was detected by electron microprobe analysis that the improved retention of the mentioned fission products in the fuel kernel is caused by formation of the stable aluminosilicates SrAl 2 Si 2 O 8 , BaAl 2 Si 2 O 8 and CsAlSi 2 O 6 in the additional aluminasilica phase of the kernel. (orig.) [de

  17. Particle production in e+e- annihilation at 29 GeV

    International Nuclear Information System (INIS)

    Derrick, M.

    1986-01-01

    Recent results on particle production in e + e - annihilation at 29 GeV are reviewed. The data were obtained using the High Resolution Spectrometer at PEP and correspond to an integrated luminosity of 300 pb -1 . The mean charged particle multiplicity in gluon jets from the three-jet events is found not to differ from that measured for quark jets. The production of the scalar meson S(975) and the tensor mesons f 0 (1270) and K*(1430) are observed and the rates are compared to the previously observed vector mesons, rho and K*(890). Finally, some of the global properties of charged particle production are presented and compared with similar results from soft hadronic collisions. 16 refs., 7 figs

  18. Rapidity correlations in inclusive two-particle production at storage ring energies

    CERN Document Server

    Dibon, Heinz; Gottfried, Christian; Nefkens, B M K; Neuhofer, G; Niebergall, F; Regler, Meinhard; Schmidt-Parzefall, W; Schubert, K R; Schumacher, P E; Winter, Klaus

    1973-01-01

    Inclusive two-particle production in the reaction pp to gamma +ch+ (anything) has been measured at the CERN ISR for four energies ( square root s=23, 30.5, 45, and 53 GeV) at two production angles of the charged particles (ch) and at eight production angles of the gamma -rays. The rapidity correlation of the two particles is weak and of short range. The peak correlation is sigma /sub inel/(d/sup 2/ sigma /sub gamma ch//d sigma /sub gamma /d sigma /sub ch/)-1=0.62+or-0.08, the correlation range (y/sub gamma /-y/sub ch/)=1.17+or-0.05, independently of s. The phi correlation extends over a wide gap in rapidity; its strength is increasing with increasing transverse momentum. (7 refs).

  19. MD 2179: Scraping of off-momentum halo after injection

    CERN Document Server

    Garcia Morales, Hector; Patecki, Marcin; Wretborn, Sven Joel; CERN. Geneva. ATS Department

    2018-01-01

    In this MD, a beam scraping was performed using the momentum primary collimator in IR3 where dispersion is high. A second scraping was performed using a TCSG in IR7 where dispersion is almost negligible. In such a way, we aim to disentangle the contribution of off-momentum particles to halo population. These scrapings will provide useful information to better understand the usual off-momentum losses we see at the start of the ramp. The MD results would also be used to benchmark simulations of off-momentum beam losses in order to gain confidence in simulation models.

  20. Effective field theory description of halo nuclei

    Science.gov (United States)

    Hammer, H.-W.; Ji, C.; Phillips, D. R.

    2017-10-01

    Nuclear halos emerge as new degrees of freedom near the neutron and proton driplines. They consist of a core and one or a few nucleons which spend most of their time in the classically-forbidden region outside the range of the interaction. Individual nucleons inside the core are thus unresolved in the halo configuration, and the low-energy effective interactions are short-range forces between the core and the valence nucleons. Similar phenomena occur in clusters of 4He atoms, cold atomic gases near a Feshbach resonance, and some exotic hadrons. In these weakly-bound quantum systems universal scaling laws for s-wave binding emerge that are independent of the details of the interaction. Effective field theory (EFT) exposes these correlations and permits the calculation of non-universal corrections to them due to short-distance effects, as well as the extension of these ideas to systems involving the Coulomb interaction and/or binding in higher angular-momentum channels. Halo nuclei exhibit all these features. Halo EFT, the EFT for halo nuclei, has been used to compute the properties of single-neutron, two-neutron, and single-proton halos of s-wave and p-wave type. This review summarizes these results for halo binding energies, radii, Coulomb dissociation, and radiative capture, as well as the connection of these properties to scattering parameters, thereby elucidating the universal correlations between all these observables. We also discuss how Halo EFT's encoding of the long-distance physics of halo nuclei can be used to check and extend ab initio calculations that include detailed modeling of their short-distance dynamics.

  1. DAMA RESULTS: DARK MATTER IN THE GALACTIC HALO

    Directory of Open Access Journals (Sweden)

    R. Bernabei

    2013-12-01

    Full Text Available Experimental efforts and theoretical developmens support that most of the Universe is Dark and a large fraction of it should be made of relic particles; many possibilities are open on their nature and interaction types. In particular, the DAMA/LIBRA experiment at Gran Sasso Laboratory (sensitive mass: ~250 kg is mainly devoted to the investigation of Dark Matter (DM particles in the Galactic halo by exploiting the model independent DM annual modulation signature with higly radiopure Na I(Tl targets. DAMA/LIBRA is the succesor of the first generation DAMA/NaI (sensitive mass: ~100 kg; cumulatively the two experiments have released so far the results obtained by analyzing an exposure of 1.17 t yr, collected over 13 annual cycles. The data show a model independent evidence of the presence of DM particles in the galactic halo at 8.9σ confidence level (C.L.. Some of the already achieved results are shortly reminded, the last upgrade occurred at fall 2010 is mentioned and future perspectives are sumarized.

  2. A THEORY OF CONSUMER’S PERCEIVED RISK UNDER THE HALO EFFECT

    Directory of Open Access Journals (Sweden)

    Dorian-Laurenţiu FLOREA

    2015-06-01

    Full Text Available Despite being largely tackled by a manifold of sciences, perceived risk is still a rather unclear concept concerning its formation and update. In today’s economy, where poor purchase decisions are so easy to make, consumers have developed mental shields residing in actions based on perceived risk. This paper develops and tests a theory of perceived risk formation under the halo effect, based on correlation analysis in two forms: rankings individuals on their contribution to the correlations increase and partial correlations. Both internal and external halo effects were found, emerging from the perceived risk component – functional risk, financial risk, social risk, physical risk, psychological risk and time risk –, brand attitude, product category attitude, consumer’s regret, others’ regret expressed through word-of-mouth, recency, and awareness of awareness. The intricate halo that was revealed needs further attention from the scientific community in order to better delimit halo sources and, eventually, to explain its variability.

  3. Production cross-sections for high mass particles and transverse momentum spectra

    International Nuclear Information System (INIS)

    Arnold, R.C.; Halzen, F.

    1977-06-01

    The concept of transverse-mass (msub(T)) scaling is examined. It is suggested that: (1) experimental data on pion transverse momentum (psub(T)) spectra provide a reliable guide to expectations for high mass particle production; (2) dimensional scaling, e.g. implied by quark-gluon dynamics, yields an estimate of msub(T) -4 spectra at ultra-high energies; however, stronger damping is expected at currently accessible energies; (3) values increase linearly with the produced particle mass. The results of msub(T) scaling are compared with estimates for high mass production in the context of the Drell-Yan model. (author)

  4. Entropy production by Q-ball decay for diluting long-lived charged particles

    International Nuclear Information System (INIS)

    Kasuya, S.

    2007-09-01

    The cosmic abundance of a long-lived charged particle such as a stau is tightly constrained by the catalyzed big bang nucleosynthesis. One of the ways to evade the constraints is to dilute those particles by a huge entropy production. We evaluate the dilution factor in a case that non-relativistic matter dominates the energy density of the universe and decays with large entropy production. We find that large Q balls can do the job, which is naturally produced in the gauge-mediated supersymmetry breaking scenario. (orig.)

  5. Structure functions and particle production in the cumulative region: two different exponentials

    International Nuclear Information System (INIS)

    Braun, M.; Vechernin, V.

    1997-01-01

    In the framework of the recently proposed (QCD-based parton model for the cumulative phenomena in the interactions with nuclei two mechanisms for particle production, direct and spectator ones, are analyzed. It is shown that due to final-state interactions the leading terms of the direct mechanism contribution are cancelled and the spectator mechanism is the dominant one. It leads to a smaller slope of the cumulative particle production rates compared to the slope of the nuclear structure function in the cumulative region x ≥ 1, in agreement with the recent experimental data

  6. Vacuum pumping by the halo plasma

    International Nuclear Information System (INIS)

    Barr, W.L.

    1985-01-01

    An estimate is made of the effective vacuum pumping speed of the halo plasma in a tandem mirror fusion reactor, and it is shown that, if the electron temperature and line density are great enough, the halo can be a very good vacuum pump. One can probably obtain the required density by recycling the ions at the halo dumps. An array of small venting ports in the dump plates allows local variation of the recycle fraction and local removal of the gas at a conveniently high pressure. This vented-port concept could introduce more flexibility in the design of pumped limiters for tokamaks

  7. Production and propagation of secondary particles near the earth; Production et propagation de particules secondaires au voisinage de la Terre

    Energy Technology Data Exchange (ETDEWEB)

    Derome, L

    2008-01-15

    A few years ago the AMS01 embarked experiment showed a particular high component of the cosmic particle flux detected below the geo-magnetic cut which was surprising because this cut represents the minimal energy that is required for cosmic radiation to reach the earth and any cosmic ray below the cut is pushed away by the earth's magnetic field. This work is based on Monte-Carlo simulations involving the generation of primary cosmic particles, their propagation in the earth magnetic field, their interaction with earth's atmosphere and the production of secondary particles. These simulations have shown that the particles below the cut are in fact particles generated in the upper part of the atmosphere, escaping from it and being trapped by the earth's magnetic field. These Monte-Carlo simulations have also been used to assess the composition of below-the-cut flux in terms of protons, electrons, positrons and light nuclei, to check the production of anti-matter in the atmosphere, and to estimate the flux of atmospheric neutrinos. (A.C.)

  8. Characterization of complete particles (VSV-G/SIN-GFP) and empty particles (VSV-G/EMPTY) in human immunodeficiency virus type 1-based lentiviral products for gene therapy: potential applications for improvement of product quality and safety.

    Science.gov (United States)

    Zhao, Yuan; Keating, Kenneth; Dolman, Carl; Thorpe, Robin

    2008-05-01

    Lentiviral vectors persist in the host and are therefore ideally suited for long-term gene therapy. To advance the use of lentiviral vectors in humans, improvement of their production, purification, and characterization has become increasingly important and challenging. In addition to cellular contaminants derived from packaging cells, empty particles without therapeutic function are the major impurities that compromise product safety and efficacy. Removal of empty particles is difficult because of their innate similarity in particle size and protein composition to the complete particles. We propose that comparison of the properties of lentiviral products with those of purposely expressed empty particles may reveal potential differences between empty and complete particles. For this, three forms of recombinant lentiviral samples, that is, recombinant vesicular stomatitis virus glycoprotein (VSV-G) proteins, empty particles (VSV-G/Empty), and complete particles (VSV-G/SIN-GFP) carrying viral RNA, were purified by size-exclusion chromatography (SEC). The SEC-purified samples were further analyzed by immunoblotting with six antibodies to examine viral and cellular proteins associated with the particles. This study has demonstrated, for the first time, important differences between VSV-G/Empty particles and complete VSV-G/SIN-GFP particles. Differences include the processing of Gag protein and the inclusion of cellular proteins in the particles. Our findings support the development of improved production, purification, and characterization methods for lentiviral products.

  9. Isospin quantum number and structure of the excited states in halo nuclei. Halo-isomers

    International Nuclear Information System (INIS)

    Izosimov, I.N.

    2015-01-01

    It has been shown that isobar-analog (IAS), double isobar-analog (DIAS), configuration (CS), and double configuration states (DCS) can simultaneously have n-n, n-p, and p-p halo components in their wave functions. Differences in halo structure of the excited and ground states can result in the formation of isomers (halo-isomers). Both the Borromean and tango halo types can be observed for n-p configurations of atomic nuclei. The structure of the ground and excited states with different isospin quantum number in halo-like nuclei is discussed. B(Mλ) and B(Eλ) for γ-transitions in 6-8 Li, 8-10 Be, 8,10,11 B, 10-14 C, 13-17 N, 15-17,19 O, and 17 F are analyzed. Special attention is given to nuclei whose ground state does not exhibit halo structure, but the excited state may have one.

  10. Review of intermediate and final product characterization on coated particles preparation

    International Nuclear Information System (INIS)

    Sukarsono; Kristanti Nurwidyaningrum

    2015-01-01

    Review of the intermediate and final product characterization on preparation of coated particles was done. Product characterization included a tool to measure the character of raw materials, intermediate product and the final product of the process, which affects the success of getting the high temperature reactor fuel are eligible. Equipment's for the characterization of such materials were pH meter, viscometer, microbalance, turbidity meter, tab density measurement, true density measurement and auto pycnometer. Being for the measurement of particles there are two types destructive testing and non destructive. Destructive testing was done by polished the particles then cross sectional imaging of particle observed using an optical microscope. In this way contains errors due to polishing treatment that could not be right on the equator section so it needs correction. Destructive testing also create waste that must be processed from the remnants of the polishing process. By using non-destructive testing, waste was not formed but the imaging results are often unclear due to lack of contrast. Development of non-destructive test equipment has been made using radiographic method and automated microscopy. The overall activity is still much needed additional tools for measurement and for processing, so that the results obtained will not rejected as the specification of nuclear fuel. Similarly, in the case of a sampling test method and limits to a product accepted or rejected, it should be determined based on statistical methods. (author)

  11. Simulation of high-energy particle production through sausage and kink instabilities in pinched plasma discharges

    International Nuclear Information System (INIS)

    Haruki, Takayuki; Yousefi, Hamid Reza; Masugata, Katsumi; Sakai, Jun-Ichi; Mizuguchi, Yusuke; Makino, Nao; Ito, Hiroaki

    2006-01-01

    In an experimental plasma, high-energy particles were observed by using a plasma focus device, to obtain energies of a few hundred keV for electrons, up to MeV for ions. In order to study the mechanism of high-energy particle production in pinched plasma discharges, a numerical simulation was introduced. By use of a three-dimensional relativistic and fully electromagnetic particle-in-cell code, the dynamics of a Z-pinch plasma, thought to be unstable against sausage and kink instabilities, are investigated. In this work, the development of sausage and kink instabilities and subsequent high-energy particle production are shown. In the model used here, cylindrically distributed electrons and ions are driven by an external electric field. The driven particles spontaneously produce a current, which begins to pinch by the Lorentz force. Initially the pinched current is unstable against a sausage instability, and then becomes unstable against a kink instability. As a result high-energy particles are observed

  12. The growth of galaxies and their gaseous haloes

    NARCIS (Netherlands)

    Voort, Frederieke van de

    2012-01-01

    Galaxies grow by accreting gas, which they need to form stars, from their surrounding haloes. These haloes, in turn, accrete gas from the diffuse intergalactic medium. Feedback from stars and black holes returns gas from the galaxy to the halo and can even expel it from the halo. This cycle of gas

  13. Hot beta particles in the lung: Results from dogs exposed to fission product radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, F.F.; Griffith, W.C.; Hobbs, C.H. [and others

    1995-12-01

    The Chernobyl nuclear reactor accident resulted in the release of uranium dioxide fuel and fission product radionuclides into the environment with the fallout of respirable, highly radioactive particles that have been termed {open_quotes}hot beta particles.{close_quotes} There is concern that these hot beta particles (containing an average of 150-20,000 Bq/particle), when inhaled and deposited in the lung, may present an extraordinary hazard for the induction of lung cancer. We reviewed data from a group of studies in dogs exposed to different quantities of beta-emitting radionuclides with varied physical half-lives to determine if those that inhaled hot beta particles were at unusual risk for lung cancer. This analysis indicates that the average dose to the lung is adequate to predict biologic effects of lung cancer for inhaled beta-emitting radionuclides in the range of 5-50 Gy to the lung and with particle activities in the range of 0.10-50 Bq/particle.

  14. Indoor fine particles: the role of terpene emissions from consumer products.

    Science.gov (United States)

    Sarwar, Golam; Olson, David A; Corsi, Richard L; Weschler, Charles J

    2004-03-01

    Consumer products can emit significant quantities of terpenes, which can react with ozone (O3). Resulting byproducts include compounds with low vapor pressures that contribute to the growth of secondary organic aerosols (SOAs). The focus of this study was to evaluate the potential for SOA growth, in the presence of O3, following the use of a lime-scented liquid air freshener, a pine-scented solid air freshener, a lemon-scented general-purpose cleaner, a wood floor cleaner, and a perfume. Two chamber experiments were performed for each of these five terpene-containing agents, one at an elevated O3 concentration and-the other at a lower O3 concentration. Particle number and mass concentrations increased and O3 concentrations decreased during each experiment. Experiments with terpene-based air fresheners produced the highest increases in particle number and mass concentrations. The results of this study clearly demonstrate that homogeneous reactions between O3 and terpenes from various consumer products can lead to increases in fine particle mass concentrations when these products are used indoors. Particle increases can occur during periods of elevated outdoor O3 concentrations or indoor O3 generation, coupled with elevated terpene releases. Human exposure to fine particles can be reduced by minimizing indoor terpene concentrations or O3 concentrations.

  15. Neutral strange particle production in neutrino and antineutrino charged-current interactions on neon

    Science.gov (United States)

    Deprospo, D.; Kalelkar, M.; Aderholz, M.; Akbari, H.; Allport, P. P.; Ammosov, V. V.; Andryakov, A.; Asratyan, A.; Badyal, S. K.; Ballagh, H. C.; Baton, J.-P.; Barth, M.; Bingham, H. H.; Brucker, E. B.; Burnstein, R. A.; Cence, R. J.; Chatterjee, T. K.; Clayton, E. F.; Corrigan, G.; Coutures, C.; Devanand; de Wolf, E.; Ermolov, P.; Erofeeva, I.; Faulkner, P. J.; Foeth, H.; Fretter, W. B.; Gapienko, G.; Gupta, V. K.; Hanlon, J.; Harigel, G.; Harris, F. A.; Ivanilov, A.; Jabiol, M.; Jacques, P.; Jain, V.; Jones, G. T.; Jones, M. D.; Kafka, T.; Kaftanov, V.; Kasper, P.; Kobrin, V.; Kohli, J. M.; Koller, E. L.; Korablev, V.; Kubantsev, M.; Lauko, M.; Lukina, O.; Lys, J. E.; Lyutov, S.; Marage, P.; Milburn, R. H.; Mittra, I. S.; Mobayyen, M. M.; Moreels, J.; Morrison, D. R.; Moskalev, V.; Murzin, V.; Myatt, G.; Nailor, P.; Naon, R.; Napier, A.; Neveu, M.; Passmore, D.; Peters, M. W.; Peterson, V. Z.; Plano, R.; Rao, N. K.; Rubin, H. A.; Ryasakov, S.; Sacton, J.; Sambyal, S. S.; Schmitz, N.; Schneps, J.; Singh, J. B.; Singh, S.; Sivoklokov, S.; Smart, W.; Smirnova, L.; Stamer, P.; Varvell, K. E.; Verluyten, L.; Wachsmuth, H.; Wainstein, S.; Willocq, S.; Yost, G. P.

    1994-12-01

    A study has been made of neutral strange particle production in νμNe and ν¯μNe charged-current interactions at a higher energy than any previous study. The experiment was done at the Fermilab Tevatron using the 15-ft. bubble chamber, and the data sample consists of 814(154) observed neutral strange particles from 6263(1115) ν(ν¯) charged-current events. For the ν beam (average event energy =150 GeV), the average multiplicities per charged-current event have been measured to be 0.408+/-0.048 for K0, 0.127+/-0.014 for Λ, and 0.015+/-0.005 for Λ¯, which are significantly greater than for lower-energy experiments. The dependence of rates on kinematical variables has been measured, and shows that both K0 and Λ production increase strongly with Eν, W2, Q2, and yB. Compared to lower-energy experiments, single-particle distributions indicate that there is much more K0 production for xF>-0.2, and the enhanced Λ production spans most of the kinematic region. Λ¯ production is mostly in the region ||xF||-0.2 there is a significant excess of Λ production over the model's prediction. The Λ hyperons are found to be polarized in the production plane.

  16. Advances in Automated QA/QC for TRISO Fuel Particle Production

    International Nuclear Information System (INIS)

    Hockey, Ronald L.; Bond, Leonard J.; Batishko, Charles R.; Gray, Joseph N.; Saurwein, John J.; Lowden, Richard A.

    2004-01-01

    Fuel in most Generation IV reactor designs typically encompasses billions of the TRISO particles. Present day QA/QC methods, done manually and in many cases destructively, cannot economically test a statistically significant fraction of the large number of the individual fuel particles required. Fully automated inspection technologies are essential to economical TRISO fuel particle production. A combination of in-line nondestructive (NDE) measurements employing electromagnetic induction and digital optical imaging analysis is currently under investigation and preliminary data indicate the potential for meeting the demands of this application. To calibrate high-speed NDE methods, surrogate fuel particle samples are being coated with layers containing a wide array of defect types found to degrade fuel performance and these are being characterized via high-resolution CT and digital radiographic images

  17. Simultaneous Polymerization and Polypeptide Particle Production via Reactive Spray-Drying.

    Science.gov (United States)

    Glavas, Lidija; Odelius, Karin; Albertsson, Ann-Christine

    2016-09-12

    A method for producing polypeptide particles via in situ polymerization of N-carboxyanhydrides during spray-drying has been developed. This method was enabled by the development of a fast and robust synthetic pathway to polypeptides using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as an initiator for the ring-opening polymerization of N-carboxyanhydrides. The polymerizations finished within 5 s and proved to be very tolerant toward impurities such as amino acid salts and water. The formed particles were prepared by mixing the monomer, N-carboxyanhydride of l-glutamic acid benzyl ester (NCAGlu) and the initiator (DBU) during the atomization process in the spray-dryer and were spherical with a size of ∼1 μm. This method combines two steps; making it a straightforward process that facilitates the production of polypeptide particles. Hence, it furthers the use of spray-drying and polypeptide particles in the pharmaceutical industry.

  18. Signatures of energy flux in particle production: a black hole birth cry and death gasp

    Energy Technology Data Exchange (ETDEWEB)

    Good, Michael R.R. [Department of Physics, Nazarbayev University,53 Kabanbay Batyr Ave., Astana, Republic of (Kazakhstan); Ong, Yen Chin [Nordic Institute for Theoretical Physics, KTH Royal Institute of Technology Stockholm University,Roslagstullsbacken 23, SE-106 91 Stockholm (Sweden)

    2015-07-27

    It is recently argued that if the Hawking radiation process is unitary, then a black hole’s mass cannot be monotonically decreasing. We examine the time dependent particle count and negative energy flux in the non-trivial conformal vacuum via the moving mirror approach. A new, exactly unitary solution is presented which emits a characteristic above-thermal positive energy burst, a thermal plateau, and negative energy flux. It is found that the characteristic positive energy flare and thermal plateau is observed in the particle outflow. However, the results of time dependent particle production show no overt indication of negative energy flux. Therefore, a black hole’s birth cry is detectable by asymptotic observers via particle count, whereas its death gasp is not.

  19. Study of charm and bottom particle production using a holographic bubble chamber

    CERN Multimedia

    2002-01-01

    The experimental arrangement consists mainly of a small, rapid cycling, heavy liquid bubble chamber, HOBC, equipped for holography and a muon detector. The high spatial resolution which can be obtained in a small holographic bubble chamber (5-10 $\\mu$m) allows a good efficiency for the detection of shortlived particles like charm and bottom particles. With the one muon trigger the proportion of these particles is greatly enhanced. \\\\\\\\For the first phase of the experiment the emphasis is on the determination of charm cross-sections. The aim is to determine the production cross-sections at 100, 200 and 300 GeV/c for different incident particles, and consequently determine the energy dependence of the charm cross-sections.

  20. Study of particle production in hadron-nucleus interactions for neutrino experiments

    CERN Document Server

    Palczewski, Tomasz Jan

    The dissertation presents a study of hadron product ion in the NA61/SHINE large acceptance spectrometer at CERN SPS. The differential cross se ctions were obtained for the production of negatively charged pions, neutral Kaons, and Lam bdas from the proton-Carbon interactions at 31 GeV/c. Methods of particle yields extraction from proton Carbon interactions were developed. An analysis chain of global correction m ethod (h- method) was established for the thin carbon target and as well for T2K replica targ et and compared to the results obtained with full particle identification. The h- method permits to cover larger phase space region not otherwise accessible. In addition, a full chain of V 0 analysis was prepared to obtain neutral Kaon and Lambda results in polar angle and momentum variables (p, θ ). Results on the differential production cross sections and mean mul tiplicities in production processes for negatively charge...

  1. Azimuthal asymmetry of particle production in Au + Au collisions at 11.6 A·GeV/c

    International Nuclear Information System (INIS)

    Kurita, Kazuyoshi

    1996-01-01

    Particle production was measured by the E866 forward spectrometer. It was reported earlier in our publication that a correlation between particle ratios and the asymmetry of energy deposition in zero degree calorimeter(ZCAL) was found. To further investigate the azimuthal asymmetry analysis, the forward hodoscope (HODO) was incorporated and the correlation between the particle production and the ''reaction plane'' will be discussed. Preliminary analysis shows enhanced in- plain proton production

  2. Constituent quarks and charge particle production in heavy-ion collisions

    International Nuclear Information System (INIS)

    Mishra, Aditya Nath; Mazumder, Rakesh; Sahoo, Raghunath; Nandi, Basanta Kumar

    2012-01-01

    Relativistic heavy-ion collisions aims at producing a state of matter which is governed by partonic degree of freedom. The pseudorapidity density of particle multiplicity and transverse energy are the key observables which provide the properties of matter produced in heavy-ion collisions. Study of their dependence on centrality and collision energy is of paramount importance to understand the particle production mechanism. This may provide insight into the partonic phase that might be created in nuclear collisions. Here, in a constituent quarks framework, charged particle and transverse energy production in heavy-ion collisions are studied both as a function of centrality and collision energy, and hence the study gives a prediction for Pb + Pb collisions

  3. Fission product Pd-SiC interaction in irradiated coated particle fuels

    International Nuclear Information System (INIS)

    Tiegs, T.N.

    1980-04-01

    Silicon carbide is the main barrier to fission product release from coated particle fuels. Consequently, degradation of the SiC must be minimized. Electron microprobe analysis has identified that palladium causes corrosion of the SiC in irradiated coated particles. Further ceramographic and electron microprobe examinations on irradiated particles with kernels ranging in composition from UO 2 to UC 2 , including PuO/sub 2 -x/ and mixed (Th, Pu) oxides, and in enrichment from 0.7 to 93.0% 235 U revealed that temperature is the major factor affecting the penetration rate of SiC by Pd. The effects of kernel composition, Pd concentration, other fission products, and SiC properties are secondary

  4. Study of conditions of production and characterization of noble metal micro-particles suspensions

    International Nuclear Information System (INIS)

    Malabre, Catherine

    1983-01-01

    As the production and identification of metal micro-particle suspensions are some aspects of issues related to nuclear fuel reprocessing, this research thesis reports the use of ruthenium, molybdenum, niobium, palladium and rhodium (fission metals) to generate such micro-particles. They are produced by erosion of two electrodes between which occurs an electric arc discharge in aqueous media. Different analytic methods are developed to determine the characteristics of so-produced colloidal solutions. A granulometry study is performed by transmission electronic microscopy, light quasi-elastic scattering, and turbidimetry associated to centrifugation. This has lead to the production of steady micro-particle suspensions which have been used in a first set of industrial trials [fr

  5. Comprehensive Analysis of the Gas- and Particle-Phase Products of VOC Oxidation

    Science.gov (United States)

    Bakker-Arkema, J.; Ziemann, P. J.

    2017-12-01

    Controlled environmental chamber studies are important for determining atmospheric reaction mechanisms and gas and aerosol products formed in the oxidation of volatile organic compounds (VOCs). Such information is necessary for developing detailed chemical models for use in predicting the atmospheric fate of VOCs and also secondary organic aerosol (SOA) formation. However, complete characterization of atmospheric oxidation reactions, including gas- and particle-phase product yields, and reaction branching ratios, are difficult to achieve. In this work, we investigated the reactions of terminal and internal alkenes with OH radicals in the presence of NOx in an attempt to fully characterize the chemistry of these systems while minimizing and accounting for the inherent uncertainties associated with environmental chamber experiments. Gas-phase products (aldehydes formed by alkoxy radical decomposition) and particle-phase products (alkyl nitrates, β-hydroxynitrates, dihydroxynitrates, 1,4-hydroxynitrates, 1,4-hydroxycarbonyls, and dihydroxycarbonyls) formed through pathways involving addition of OH to the C=C double bond as well as H-atom abstraction were identified and quantified using a suite of analytical techniques. Particle-phase products were analyzed in real time with a thermal desorption particle beam mass spectrometer; and off-line by collection onto filters, extraction, and subsequent analysis of functional groups by derivatization-spectrophotometric methods developed in our lab. Derivatized products were also separated by liquid chromatography for molecular quantitation by UV absorbance and identification using chemical ionization-ion trap mass spectrometry. Gas phase aldehydes were analyzed off-line by collection onto Tenax and a 5-channel denuder with subsequent analysis by gas chromatography, or by collection onto DNPH-coated cartridges and subsequent analysis by liquid chromatography. The full product identification and quantitation, with careful

  6. On physical scales of dark matter halos

    International Nuclear Information System (INIS)

    Zemp, Marcel

    2014-01-01

    It is common practice to describe formal size and mass scales of dark matter halos as spherical overdensities with respect to an evolving density threshold. Here, we critically investigate the evolutionary effects of several such commonly used definitions and compare them to the halo evolution within fixed physical scales as well as to the evolution of other intrinsic physical properties of dark matter halos. It is shown that, in general, the traditional way of characterizing sizes and masses of halos dramatically overpredicts the degree of evolution in the last 10 Gyr, especially for low-mass halos. This pseudo-evolution leads to the illusion of growth even though there are no major changes within fixed physical scales. Such formal size definitions also serve as proxies for the virialized region of a halo in the literature. In general, those spherical overdensity scales do not coincide with the virialized region. A physically more precise nomenclature would be to simply characterize them by their very definition instead of calling such formal size and mass definitions 'virial'. In general, we find a discrepancy between the evolution of the underlying physical structure of dark matter halos seen in cosmological structure formation simulations and pseudo-evolving formal virial quantities. We question the importance of the role of formal virial quantities currently ubiquitously used in descriptions, models, and relations that involve properties of dark matter structures. Concepts and relations based on pseudo-evolving formal virial quantities do not properly reflect the actual evolution of dark matter halos and lead to an inaccurate picture of the physical evolution of our universe.

  7. Coherent production on nuclei and measurements of total cross sections for unstable particles

    International Nuclear Information System (INIS)

    Czyz, W.; Zielinski, M.

    1980-01-01

    The Koelbig-Margolis Formula is fitted to some explicity nonperturbative models of diffractive production. It is shown that, in spite of the fact that the standard procedure of fitting the integrated cross sections may give acceptable fits, thus obtained ''cross sections of unstable particles'', grossly disagree with the ''true'' cross sections known exactly from the models. (author)

  8. Higher-order QCD corrections to inclusive particle production in panti p collisions

    International Nuclear Information System (INIS)

    Borzumati, F.M.; Kniehl, B.A.; Kramer, G.

    1992-10-01

    Inclusive single-particle production cross sections have been calculated including higher-order QCD corrections. Transverse-momentum and rapidity distributions are presented and the scale dependence is studied. The results are compared with experimental data from the CERN Spanti pS Collider and the Fermilab Tevatron. (orig.)

  9. Quantum production of particles (the Hawking effect) in nonstationary black holes

    International Nuclear Information System (INIS)

    Volovich, I.V.; Zagrebnov, V.A.; Frolov, V.P.; AN SSSR, Moscow. Fizicheskij Inst.)

    1976-01-01

    Particle production in a gravitational field of a black hole with changing mass is considered. It is shown that in the case when parameters are changed adiabatically taking into account the nonstationarity is reduced effectively to the taking into account the dependence of the Hawking radiation temperature on the retarded time

  10. Quantum production of particles (the Hawking effect) in nonstationary black holes

    Energy Technology Data Exchange (ETDEWEB)

    Volovich, I V; Zagrebnov, V A; Frolov, V P [Joint Inst. for Nuclear Research, Dubna (USSR); AN SSSR, Moscow. Fizicheskij Inst.)

    1976-11-01

    Particle production in a gravitational field of a black hole with changing mass is considered. It is shown that in the case when parameters are changed adiabatically taking into account the nonstationarity is reduced effectively to the taking into account the dependence of the Hawking radiation temperature on the retarded time.

  11. Reheating via Gravitational Particle Production in Simple Models of Quintessence or ΛCDM Inflation

    Directory of Open Access Journals (Sweden)

    Jaume de Haro

    2017-11-01

    Full Text Available We have tested some simple Λ CDM (the same test is also valid for quintessence inflation models, imposing that they match with the recent observational data provided by the BICEP and Planck’s team and leading to a reheating temperature, which is obtained via gravitational particle production after inflation, supporting the nucleosynthesis success.

  12. Study of strange particle production by neutral currents induced by 1 and 12 GeV neutrinos and antineutrinos

    International Nuclear Information System (INIS)

    Francois, T.L.B.

    1977-01-01

    Strange particles production by weak neutral currents was experimentally studied. The first result is a direct confirmation that neutral currents conserve strangeness (by an upper limit on ΔS=-1 production). The two other results, production rate of strange neutral particles and ratio of strange particles production for antineutrinos and neutrinos, prove that these particles are mainly produced in the final hadronic state rather than on strange sea-quarks and give an upper limit on the rate of this type of quark in the nucleon [fr

  13. Model for GCR-particle fluxes in stony meteorites and production rates of cosmogenic nuclides

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1984-01-01

    A model is presented for the differential fluxes of galactic-cosmic-ray (GCR) particles with energies above 1 MeV inside any spherical stony meteorite as a function of the meteorite's radius and the sample's depth. This model is based on the Reedy-Arnold equations for the energy-dependent fluxes of GCR particles in the moon and is an extension of flux parameters that were derived for several meteorites of various sizes. This flux is used to calculate the production rates of many cosmogenic nuclides as a function of radius and depth. The peak production rates for most nuclides made by the reactions of energetic GCR particles occur near the centers of meteorites with radii of 40 to 70 g cm -2 . Although the model has some limitations, it reproduces well the basic trends for the depth-dependent production of cosmogenic nuclides in stony meteorites of various radii. These production profiles agree fairly well with measurements of cosmogenic nuclides in meteorites. Some of these production profiles are different than those calculated by others. The chemical dependence of the production rates for several nuclides varies with size and depth. 25 references, 8 figures

  14. MODIFIED GRAVITY SPINS UP GALACTIC HALOS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jounghun [Astronomy Program, Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747 (Korea, Republic of); Zhao, Gong-Bo [National Astronomy Observatories, Chinese Academy of Science, Beijing 100012 (China); Li, Baojiu [Institute of Computational Cosmology, Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Koyama, Kazuya, E-mail: jounghun@astro.snu.ac.kr [Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom)

    2013-01-20

    We investigate the effect of modified gravity on the specific angular momentum of galactic halos by analyzing the halo catalogs at z = 0 from high-resolution N-body simulations for a f(R) gravity model that meets the solar-system constraint. It is shown that the galactic halos in the f(R) gravity model tend to acquire significantly higher specific angular momentum than those in the standard {Lambda}CDM model. The largest difference in the specific angular momentum distribution between these two models occurs for the case of isolated galactic halos with mass less than 10{sup 11} h {sup -1} M {sub Sun }, which are likely least shielded by the chameleon screening mechanism. As the specific angular momentum of galactic halos is rather insensitive to other cosmological parameters, it can in principle be an independent discriminator of modified gravity. We speculate a possibility of using the relative abundance of low surface brightness galaxies (LSBGs) as a test of general relativity given that the formation of the LSBGs occurs in fast spinning dark halos.

  15. ANGULAR MOMENTUM ACQUISITION IN GALAXY HALOS

    International Nuclear Information System (INIS)

    Stewart, Kyle R.; Brooks, Alyson M.; Bullock, James S.; Maller, Ariyeh H.; Diemand, Jürg; Wadsley, James; Moustakas, Leonidas A.

    2013-01-01

    We use high-resolution cosmological hydrodynamic simulations to study the angular momentum acquisition of gaseous halos around Milky-Way-sized galaxies. We find that cold mode accreted gas enters a galaxy halo with ∼70% more specific angular momentum than dark matter averaged over cosmic time (though with a very large dispersion). In fact, we find that all matter has a higher spin parameter when measured at accretion than when averaged over the entire halo lifetime, and is well characterized by λ ∼ 0.1, at accretion. Combined with the fact that cold flow gas spends a relatively short time (1-2 dynamical times) in the halo before sinking to the center, this naturally explains why cold flow halo gas has a specific angular momentum much higher than that of the halo and often forms ''cold flow disks.'' We demonstrate that the higher angular momentum of cold flow gas is related to the fact that it tends to be accreted along filaments.

  16. Shell closures, loosely bound structures, and halos in exotic nuclei

    International Nuclear Information System (INIS)

    Saxena, G.; Singh, D.

    2013-01-01

    Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

  17. Shell closures, loosely bound structures, and halos in exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, G., E-mail: gauravphy@gmail.com [Govt. Women Engineering College, Department of Physics (India); Singh, D. [University of Rajasthan, Department of Physics (India)

    2013-04-15

    Inspired by the recent experiments indicating doubly magic nuclei that lie near the drip-line and encouraged by the success of our relativistic mean-field (RMF) plus state-dependent BCS approach to the description of the ground-state properties of drip-line nuclei, we develop this approach further, across the entire periodic table, to explore magic nuclei, loosely bound structures, and halo formation in exotic nuclei. In our RMF+BCS approach, the single-particle continuum corresponding to the RMF is replaced by a set of discrete positive-energy states for the calculations of pairing energy. Detailed analysis of the single-particle spectrum, pairing energies, and densities of the nuclei predict the unusual proton shell closures at proton numbers Z = 6, 14, 16, 34, and unusual neutron shell closures at neutron numbers N = 6, 14, 16, 34, 40, 70, 112. Further, in several nuclei like the neutron-rich isotopes of Ca, Zr, Mo, etc., the gradual filling of lowlying single-particle resonant state together with weakly bound single-particle states lying close to the continuum threshold helps accommodate more neutrons but with an extremely small increase in the binding energy. This gives rise to the occurrence of loosely bound systems of neutron-rich nuclei with a large neutron-to-proton ratio. In general, the halo-like formation, irrespective of the existence of any resonant state, is seen to be due to the large spatial extension of the wave functions for the weakly bound single-particle states with low orbital angular momentum having very small or no centrifugal barriers.

  18. Exhaust, ELM and halo physics using the MAST tokamak

    International Nuclear Information System (INIS)

    Counsell, G. F.

    2002-01-01

    Scalings for the SOL width on MAST extend the parameter range of conventional devices but confirm a negative dependence on power flow across the separatrix. In L-mode and at ELM peaks, >95% of power to the targets arrives to the outboard side. Peak heat flux densities rise by a factor 2∼6 during ELMs and are accompanied by a shift in the strike-point location but by little change in the target heat flux width. Energy loss per ELM as a percentage of pedestal energy and pedestal collisionality appear uncorrelated, possibly because ELMs on MAST are dominated by convective transport. Modelling shows that parallel gradients in the magnitude of the magnetic field in MAST may drive strong upstream flows. Broadening of the target heat flux width by divertor biasing is being explored as a means of reducing target power loading in next-step devices and has facilitated halo current measurements using series resistors. Halo currents are always less than 30% of plasma current and the product of toroidal peaking factor and halo current fraction is ∼50% of the ITER design limit. Varying the series resistance demonstrates that the VDE behaves more as a voltage source than a current source. (author)

  19. Exhaust, ELM and Halo physics using the MAST tokamak

    International Nuclear Information System (INIS)

    Counsell, G.F.; Ahn, J-W.; Kirk, A.; Helander, P.; Martin, R.; Tabasso, A.; Wilson, H.R.; Cohen, R.H.; Ryutov, D.D.; Yang, Y.

    2003-01-01

    The scrape-off layer (Sol) and divertor target plasma of a large spherical tokamak (ST) is characterised in detail for the first time. Scalings for the SOL heat flux width in MAST are developed and compared to conventional tokamaks. Modelling reveals the significance of the mirror force to the ST SOL. Core energy losses, including during ELMs, in MAST arrive predominantly (>80%) to the outboard targets in all geometries. Convective transport dominates energy losses during ELMs and MHD analysis suggests ELMs in MAST are Type III even at auxiliary heating powers well above the L-H threshold. ELMs are associated with a poloidally and/or toroidally localised radial efflux at ∼1 km/s well into the far SOL but not with any broadening of the target heat flux width. Toroidally asymmetric divertor biasing experiments have been conducted in an attempt to broaden the target heat flux width, with promising results. During vertical displacement events, the maximum product of the toroidal peaking factor and halo current fraction remains below 0.3, around half the ITER design limit. Evidence is presented that the resistance of the halo current path may have an impact on the distribution of halo current. (author)

  20. Decay Properties of the Halo Nucleus $^{11}$Li

    CERN Multimedia

    2002-01-01

    During the past years a considerable experimental effort has been devoted to the production and study of nuclei close to the neutron and proton drip-lines. The most spectacular phenomenon encountered is the occurrence of neutron halos in the loosely bound neutron rich nuclei. \\\\ \\\\ Another interesting feature, observed at ISOLDE, which most likely is connected to the halo structure, is the very strong (super-allowed) Gamow-Teller $\\beta$- transitions to highly excited states which are systematically observed for the lightest neutron rich drip-line nuclei. These transitions might be viewed as arising from the quasi-free $\\beta$ -decay of the halo neutrons. It is proposed to make a detailed study of the $\\beta$- strength function for $^{11}$Li, a nuclide having a half-life of 8.2 ms and a Q $\\beta$-value of 20.73~MeV. \\\\ \\\\ So far only a lower limit of the Gamow-Teller transition rate to highly excited states ($\\approx$~18.5~MeV) in the daughter nucleus has been obtained from measurements of $\\beta$-delayed tri...

  1. Astrophysical dark matter: candidates from particle physics and detection possibilities

    International Nuclear Information System (INIS)

    Freese, K.

    1989-01-01

    In this talk, I will discuss the arguments that 50% to 90% of the matter in galaxies, including our own, is made of an unknown type of dark matter. I will review the reason why cosmologists believe Ω = 1 and illustrate the contrast with the limits on the amount of baryonic matter from element abundances in Big Bang Nucleosynthesis. Other arguments for nonbaryonic dark matter will also be discussed. Candidates for the dark matter from particle physics will be presented. I will focus on cold dark matter candidates known as WIMPs, weakly interacting massive (O(GeV)) particles. I will try to illustrate why these particles are interesting for astrophysics and outline ideas for cornering them. Detection possibilities for these particles include indirect detection, which takes advantage of the annihilation products of these particles in the galactic halo, the sun, or the earth. Direct detection via newly proposed cryogenic detectors must be sensitive to <∼ keV energy deposits. Annual modulation of the dark matter signal can be used as a signature for these halo particles. I hope to motivate the interest in these particles and discuss ideas for finding them

  2. Structures of the particles of the condensed dispersed phase in solid fuel combustion products plasma

    International Nuclear Information System (INIS)

    Samaryan, A.A.; Chernyshev, A.V.; Nefedov, A.P.; Petrov, O.F.; Fortov, V.E.; Mikhailov, Yu.M.; Mintsev, V.B.

    2000-01-01

    The results of experimental investigations of a type of dusty plasma which has been least studied--the plasma of solid fuel combustion products--were presented. Experiments to determine the parameters of the plasma of the combustion products of synthetic solid fuels with various compositions together with simultaneous diagnostics of the degree of ordering of the structures of the particles of the dispersed condensed phase were performed. The measurements showed that the charge composition of the plasma of the solid fuels combustion products depends strongly on the easily ionized alkali-metal impurities which are always present in synthetic fuel in one or another amount. An ordered arrangement of the particles of a condensed dispersed phase in structures that form in a boundary region between the high-temperature and condensation zones was observed for samples of aluminum-coated solid fuels with a low content of alkali-metal impurities

  3. Particle production after inflation with non-minimal derivative coupling to gravity

    International Nuclear Information System (INIS)

    Ema, Yohei; Jinno, Ryusuke; Nakayama, Kazunori; Mukaida, Kyohei

    2015-01-01

    We study cosmological evolution after inflation in models with non-minimal derivative coupling to gravity. The background dynamics is solved and particle production associated with rapidly oscillating Hubble parameter is studied in detail. In addition, production of gravitons through the non-minimal derivative coupling with the inflaton is studied. We also find that the sound speed squared of the scalar perturbation oscillates between positive and negative values when the non-minimal derivative coupling dominates over the minimal kinetic term. This may lead to an instability of this model. We point out that the particle production rates are the same as those in the Einstein gravity with the minimal kinetic term, if we require the sound speed squared is positive definite

  4. Transverse energy and charged particle production in heavy-ion collisions: from RHIC to LHC

    International Nuclear Information System (INIS)

    Sahoo, Raghunath; Mishra, Aditya Nath

    2014-01-01

    We study the charged particle and transverse energy production mechanism from AGS, SPS, Relativistic Heavy-Ion Collider (RHIC) to Large Hadron Collider (LHC) energies in the framework of nucleon and quark participants. At RHIC and LHC energies, the number of nucleons-normalized charged particle and transverse energy density in pseudorapidity, which shows a monotonic rise with centrality, turns out to be an almost centrality independent scaling behavior when normalized to the number of participant quarks. A universal function which is a combination of logarithmic and power-law, describes well the charged particle and transverse energy production both at nucleon and quark participant level for the whole range of collision energies. Energy dependent production mechanisms are discussed both for nucleonic and partonic level. Predictions are made for the pseudorapidity densities of transverse energy, charged particle multiplicity and their ratio (the barometric observable, [dE T /dη]/[dN ch /dη] ≡ E T /N ch ) at mid-rapidity for Pb + Pb collisions at √s NN = 5.5 TeV. A comparison with models based on gluon saturation and statistical hadron gas is made for the energy dependence of E T /N ch . (author)

  5. Collision dynamics and particle production in relativistic nucleus- nucleus collisions at CERN

    International Nuclear Information System (INIS)

    Harris, J.W.

    1990-03-01

    The possibility of forming a quark-gluon plasma is the primary motivation for studying nucleus-nucleus collisions at very high energies. Various ''signatures'' for the existence of a quark-gluon plasma in these collisions have been proposed. These include an enhancement in the production of strange particles, suppression of J/Ψ production, observation of direct photons from the plasma, event-by-event fluctuations in the rapidity distributions of produced particles, and various other observables. However, the system will evolve dynamically from a pure plasma or mixed phase through expansion, cooling, hadronization and freezeout into the final state particles. Therefore, to be able to determine that a new, transient state of matter has been formed it will be necessary to understand the space-time evolution of the collision process and the microscopic structure of hadronic interactions, at the level of quarks and gluons, at high temperatures and densities. In this talk I will review briefly the present state of our understanding of the dynamics of these collisions and, in addition, present a few recent results on particle production from the NA35 experiment at CERN. 21 refs., 5 figs

  6. Particle production in field theories coupled to strong external sources, I: Formalism and main results

    International Nuclear Information System (INIS)

    Gelis, Francois; Venugopalan, Raju

    2006-01-01

    We develop a formalism for particle production in a field theory coupled to a strong time-dependent external source. An example of such a theory is the color glass condensate. We derive a formula, in terms of cut vacuum-vacuum Feynman graphs, for the probability of producing a given number of particles. This formula is valid to all orders in the coupling constant. The distribution of multiplicities is non-Poissonian, even in the classical approximation. We investigate an alternative method of calculating the mean multiplicity. At leading order, the average multiplicity can be expressed in terms of retarded solutions of classical equations of motion. We demonstrate that the average multiplicity at next-to-leading order can be formulated as an initial value problem by solving equations of motion for small fluctuation fields with retarded boundary conditions. The variance of the distribution can be calculated in a similar fashion. Our formalism therefore provides a framework to compute from first principles particle production in proton-nucleus and nucleus-nucleus collisions beyond leading order in the coupling constant and to all orders in the source density. We also provide a transparent interpretation (in conventional field theory language) of the well-known Abramovsky-Gribov-Kancheli (AGK) cancellations. Explicit connections are made between the framework for multi-particle production developed here and the framework of reggeon field theory

  7. Products and kinetics of the heterogeneous reaction of suspended vinclozolin particles with ozone.

    Science.gov (United States)

    Gan, Jie; Yang, Bo; Zhang, Yang; Shu, Xi; Liu, Changgeng; Shu, Jinian

    2010-11-25

    Vinclozolin is a widely used fungicide that can be released into the atmosphere via application and volatilization. This paper reports an experimental investigation on the heterogeneous ozonation of vinclozolin particles. The ozonation of vinclozolin adsorbed on azelaic acid particles under pseudo-first-order conditions is investigated online with a vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS). The ozonation products are analyzed with a combination of VUV-ATOFMS and GC/MS. Two main ozonation products are observed. The formation of the ozonation products results from addition of O(3) on the C-C double bond of the vinyl group. The heterogeneous reactive rate constant of vinclozolin particles under room temperature is (2.4 ± 0.4) × 10(-17) cm(3) molecules(-1) s(-1), with a corresponding lifetime at 100 ppbv O(3) of 4.3 ± 0.7 h, which is almost comparable with the estimated lifetime due to the reaction with atmospheric OH radicals (∼1.7 h). The reactive uptake coefficient for O(3) on vinclozolin particles is (6.1 ± 1.0) × 10(-4).

  8. In situ thermal polymerisation of natural oils as novel sustainable approach in nanographite particle production

    Science.gov (United States)

    Datsyuk, Vitaliy; Trotsenko, Svitlana; Reich, Stephanie

    2018-01-01

    A sustainable approach to graphite exfoliation via in situ thermal polymerization of fish oil results in the production of nanographite particles. The material was characterized by elemental analysis, transmission electron microscopy, and Raman spectroscopy. The thermal polymerization of fish oil was controlled by monitoring the viscosity and measuring the iodine number. The number of structural defects on the graphitic surface remained constant during the synthesis. The protocol leads to a hydrophobization of the nanographite surface. Immobilized polyoil islands create sterical hindrance and stabilize the nanographite particles in engineering polymers.

  9. High flux Particle Bed Reactor systems for rapid transmutation of actinides and long lived fission products

    International Nuclear Information System (INIS)

    Powell, J.; Ludewig, H.; Maise, G.; Steinberg, M.; Todosow, M.

    1993-01-01

    An initial assessment of several actinide/LLFP burner concepts based on the Particle Bed Reactor (PBR) is described. The high power density/flux level achievable with the PBR make it an attractive candidate for this application. The PBR based actinide burner concept also possesses a number of safety and economic benefits relative to other reactor based transmutation approaches including a low inventory of radionuclides, and high integrity, coated fuel particles which can withstand extremely high in temperatures while retaining virtually all fission products. In addition the reactor also posesses a number of ''engineered safety features,'' which, along with the use of high temperature capable materials further enhance its safety characteristics

  10. Absence of particle production and factorization of the s-matrix in 1 + 1 dimensional models

    International Nuclear Information System (INIS)

    Parke, S.

    1980-01-01

    In massive, 1 + 1 dimensional, local, quantum field theories the existence of two conserved charges is shown to be a sufficient condition for the absence of particle production and factorization of the s-matrix. These charges must commute and be integrals of local current densities. Their transformation properties under the Lorentz group must be different and also different from the transformation properties under the Lorentz group must be different and also different from the transformation properties pf a vector or a scalar. Also, they must not annihilate any single-particle momentum eigenstate. (orig.)

  11. Gravitationally induced particle production and its impact on the WIMP abundance

    Directory of Open Access Journals (Sweden)

    I. Baranov

    2015-12-01

    Full Text Available A large set of independent astronomical observations have provided a strong evidence for nonbaryonic dark matter in the Universe. One of the most investigated candidates is an unknown long-lived Weakly Interacting Massive Particle (WIMP which was in thermal equilibrium with the primeval plasma. Here we investigate the WIMP abundance based on the relativistic kinetic treatment for gravitationally induced particle production recently proposed in the literature (Lima and Baranov, 2014 [16]. The new evolution equation is deduced and solved both numerically and through a semi-analytical approach. The predictions of the WIMP observables are discussed and compared with the ones obtained in the standard approach.

  12. Measurements of very forward particles production spectra at LHC: the LHCf experiment

    CERN Document Server

    Berti, Eugenio; Bonechi, Lorenzo; Bongi, Massimo; Castellini, Guido; D'Alessandro, Raffaello; Haguenauer, Maurice; Itow, Yoshitaka; Iwata, Taiki; Kasahara, Katsuaki; Makino, Yuya; Masuda, Kimiaki; Matsubayashi, Eri; Menjo, Hiroaki; Muraki, Yasushi; Papini, Paolo; Ricciarini, Sergio; Sako, Takashi; Suzuki, Takuya; Tamura, Tadahisa; Tiberio, Alessio; Torii, Shoji; Tricomi, Alessia; Turner, W C; Ueno, Mana; Zhou, Qi Dong

    2017-01-01

    Thanks to two small sampling calorimeters installed in the LHC tunnel at ±140 m from IP1, the LHC forward (LHCf) experiment is able to detect neutral particles produced by high energy proton-ion collisions in the very forward region (pseudo-rapidity η > 8.4). The main aim of LHCf is to provide precise measurements of the production spectra relative to these particles, in order to tune hadronic interaction models used by ground-based cosmic rays experiments. In this paper we will present the current status of the LHCf experiment, regarding in particular collected data and analysis results, as well as future prospects

  13. Gravitationally induced adiabatic particle production: from big bang to de Sitter

    Science.gov (United States)

    de Haro, Jaume; Pan, Supriya

    2016-08-01

    In the background of a flat homogeneous and isotropic space-time, we consider a scenario of the Universe driven by the gravitationally induced ‘adiabatic’ particle production with constant creation rate. We have shown that this Universe attains a big bang singularity in the past and at late-time it asymptotically becomes de Sitter. To clarify this model Universe, we performed a dynamical analysis and found that the Universe attains a thermodynamic equilibrium in this late de Sitter phase. Finally, for the first time, we have discussed the possible effects of ‘adiabatic’ particle creations in the context of loop quantum cosmology.

  14. Gravitationally induced adiabatic particle production: from big bang to de Sitter

    International Nuclear Information System (INIS)

    Haro, Jaume de; Pan, Supriya

    2016-01-01

    In the background of a flat homogeneous and isotropic space–time, we consider a scenario of the Universe driven by the gravitationally induced ‘adiabatic’ particle production with constant creation rate. We have shown that this Universe attains a big bang singularity in the past and at late-time it asymptotically becomes de Sitter. To clarify this model Universe, we performed a dynamical analysis and found that the Universe attains a thermodynamic equilibrium in this late de Sitter phase. Finally, for the first time, we have discussed the possible effects of ‘adiabatic’ particle creations in the context of loop quantum cosmology. (paper)

  15. Production and characterization of monodisperse uranium particles for nuclear safeguards applications

    International Nuclear Information System (INIS)

    Knott, Alexander

    2016-01-01

    Environmental sampling is a very effective measure to detect undeclared nuclear activities. Generally, samples are taken as swipe samples on cotton. These swipes contain minute quantities of particulates which have an inherent signature of their production and release scenario. These inspection samples are assessed for their morphology, elemental composition and their isotopic vectors. Mass spectrometry plays a crucial role in determining the isotopic ratios of uranium. Method validation and instrument calibration with well-characterized quality control (QC)-materials, reference materials (RMs) and certified reference materials (CRMs) ensures reliable data output. Currently, the availability of suitable well defined microparticles containing uranium and plutonium reference materials is very limited. Primarily, metals, oxides and various uranium and plutonium containing solutions are commercially available. Therefore, the IAEA's Safeguards Analytical Services (SGAS) cooperates with the Institute of Nuclear Waste Management and Reactor Safety (IEK-6) at the Forschungszentrum Juelich GmbH in a joint task entitled ''Production of Particle Reference Materials''. The work presented in this thesis has been partially funded by the IAEA, Forschungszentrum Juelich GmbH and the Federal Ministry of Economic Affairs and Energy (BMWi) through the ''Joint Program on the Technical Development and Further Improvement of IAEA Safeguards between the Government of the Federal Republic of Germany and the IAEA''. The first step towards monodisperse microparticles was the development of pure uranium oxide particles made from certified reference materials. The focus of the dissertation is (1) the implementation of a working setup to produce monodisperse uranium oxide particles and (2) the characterization of these particles towards the application as QC-material. Monodisperse uranium oxide particles were produced by spray pyrolysis. It was demonstrated that the particle size can be

  16. Ultra Light Axionic Dark Matter: Galactic Halos and Implications for Observations with Pulsar Timing Arrays

    Science.gov (United States)

    de Martino, Ivan; Broadhurst, Tom; Tye, S.-H. Henry; Chiueh, Tzihong; Shive, Hsi-Yu; Lazkoz, Ruth

    2018-01-01

    The cold dark matter (CDM) paradigm successfully explains the cosmic structure over an enormous span of redshifts. However, it fails when probing the innermost regions of dark matter halos and the properties of the Milky Way's dwarf galaxy satellites. Moreover, the lack of experimental detection of Weakly Interacting Massive Particle (WIMP) favors alternative candidates such as light axionic dark matter that naturally arise in string theory. Cosmological N-body simulations have shown that axionic dark matter forms a solitonic core of size of ≃ 150 pc in the innermost region of the galactic halos. The oscillating scalar field associated to the axionic dark matter halo produces an oscillating gravitational potential that induces a time dilation of the pulse arrival time of ≃ 400 ns/(m_B/10^{-22} eV) for pulsar within such a solitonic core. Over the whole galaxy, the averaged predicted signal may be detectable with current and forthcoming pulsar timing array telescopes.

  17. Large-scale structure after COBE: Peculiar velocities and correlations of cold dark matter halos

    Science.gov (United States)

    Zurek, Wojciech H.; Quinn, Peter J.; Salmon, John K.; Warren, Michael S.

    1994-01-01

    Large N-body simulations on parallel supercomputers allow one to simultaneously investigate large-scale structure and the formation of galactic halos with unprecedented resolution. Our study shows that the masses as well as the spatial distribution of halos on scales of tens of megaparsecs in a cold dark matter (CDM) universe with the spectrum normalized to the anisotropies detected by Cosmic Background Explorer (COBE) is compatible with the observations. We also show that the average value of the relative pairwise velocity dispersion sigma(sub v) - used as a principal argument against COBE-normalized CDM models-is significantly lower for halos than for individual particles. When the observational methods of extracting sigma(sub v) are applied to the redshift catalogs obtained from the numerical experiments, estimates differ significantly between different observation-sized samples and overlap observational estimates obtained following the same procedure.

  18. A Halo Event observed by the Hybrid Experiment at Mt. Chacaltaya

    International Nuclear Information System (INIS)

    Aoki, H.; Hashimoto, K.; Honda, K.; Inoue, N.; Kawasumi, N.; Martinic, N.; Navia O, C.; Ochi, N.; Ohmori, N.; Ohsawa, A.; Oliveira, C.; Shinozaki, K.; Tamada, M.; Ticona, R.; Tsushima, I.

    2006-01-01

    An experiment using an air shower array, a hadron calorimeter and an emulsion chamber is under way at Mt. Chacaltaya (5200 m, Bolivia). One of the highest energy events, having a halo (∼ 1 cm) in the centre of the family together with many γ-ray and hadron showers, is analyzed in detail. Available data for the event are on the halo (E halo =750 TeV) and on the high energy particles of electron/photon components by the emulsion chamber, and on the characteristics of the accompanied air shower (Ne=7.0x10 7 , s=0.59) by the air shower array. The diagram of the air shower size and the total energy of electron/photon components in the family, which shows discrepancy between the experimental data and simulated events (QGSJET code for nuclear collisions) in our previous reports, is discussed including the present event

  19. Dark matter halos with cores from hierarchical structure formation

    International Nuclear Information System (INIS)

    Strigari, Louis E.; Kaplinghat, Manoj; Bullock, James S.

    2007-01-01

    We show that dark matter emerging from late decays (z or approx. 0.1 Mpc), and simultaneously generates observable constant-density cores in small dark matter halos. We refer to this class of models as meta-cold dark matter (mCDM), because it is born with nonrelativistic velocities from the decays of cold thermal relics. The constant-density cores are a result of the low phase-space density of mCDM at birth. Warm dark matter cannot produce similar size phase-space limited cores without saturating the Lyα power spectrum bounds. Dark matter-dominated galaxy rotation curves and stellar velocity dispersion profiles may provide the best means to discriminate between mCDM and CDM. mCDM candidates are motivated by the particle spectrum of supersymmetric and extra dimensional extensions to the standard model of particle physics

  20. Mini-jet production in proton-antiproton interactions and particle production in heavy-ion collisions

    International Nuclear Information System (INIS)

    Wang Haiqiao.

    1997-04-01

    The thesis is based on the data analysis and detector development of the EMU01/CERN, E863/BNL and UA1/CERN experiments. Particle fluctuations are studied with the scaled factorial moments in the fragmentation region of oxygen induced emulsion interactions from 3.7 to 200 A GeV. The intermittency indices show an energy independent behaviour in the target and projectile regions of pseudorapidity. In order to study the origin of the fluctuations, jet-like and ring-like substructures of particles produced in the azimuthal plane are investigated for the S - Au, S - Em and O - Em interactions at 200 A GeV. The study shows that the two particle azimuthal correlations can be well understood if Bose-Einstein correlations and γ-conversion are included. A nuclear rescattering model, which incorporates the FRITIOF model, has been developed. The model can well describe multiplicity distributions of slow recoiling protons, evaporation particles and their correlations with particles produced in high energy heavy ion collisions. In order to improve the measurements of Pb induced collisions, an automatic system based on the CCD technique and image processing was developed. This system has been used to measure densities of the particles produced. Mini-jet production is studied using the UA1 1987 minimum bias data sample for p (anti) interaction at s 1/2 0 630 GeV. The study shows that the transverse energy distribution of mini-jets is in good agreement with the QCD prediction. The angular distributions of two leading jets show the behaviour of elastic scattering of partons with gluon exchange. 86 refs

  1. Revealing the Cosmic Web-dependent Halo Bias

    Science.gov (United States)

    Yang, Xiaohu; Zhang, Youcai; Lu, Tianhuan; Wang, Huiyuan; Shi, Feng; Tweed, Dylan; Li, Shijie; Luo, Wentao; Lu, Yi; Yang, Lei

    2017-10-01

    Halo bias is the one of the key ingredients of the halo models. It was shown at a given redshift to be only dependent, to the first order, on the halo mass. In this study, four types of cosmic web environments—clusters, filaments, sheets, and voids—are defined within a state-of-the-art high-resolution N-body simulation. Within these environments, we use both halo-dark matter cross correlation and halo-halo autocorrelation functions to probe the clustering properties of halos. The nature of the halo bias differs strongly between the four different cosmic web environments described here. With respect to the overall population, halos in clusters have significantly lower biases in the {10}11.0˜ {10}13.5 {h}-1 {M}⊙ mass range. In other environments, however, halos show extremely enhanced biases up to a factor 10 in voids for halos of mass ˜ {10}12.0 {h}-1 {M}⊙ . Such a strong cosmic web environment dependence in the halo bias may play an important role in future cosmological and galaxy formation studies. Within this cosmic web framework, the age dependency of halo bias is found to be only significant in clusters and filaments for relatively small halos ≲ {10}12.5 {h}-1 {M}⊙ .

  2. GRAVITATIONALLY CONSISTENT HALO CATALOGS AND MERGER TREES FOR PRECISION COSMOLOGY

    International Nuclear Information System (INIS)

    Behroozi, Peter S.; Wechsler, Risa H.; Wu, Hao-Yi; Busha, Michael T.; Klypin, Anatoly A.; Primack, Joel R.

    2013-01-01

    We present a new algorithm for generating merger trees and halo catalogs which explicitly ensures consistency of halo properties (mass, position, and velocity) across time steps. Our algorithm has demonstrated the ability to improve both the completeness (through detecting and inserting otherwise missing halos) and purity (through detecting and removing spurious objects) of both merger trees and halo catalogs. In addition, our method is able to robustly measure the self-consistency of halo finders; it is the first to directly measure the uncertainties in halo positions, halo velocities, and the halo mass function for a given halo finder based on consistency between snapshots in cosmological simulations. We use this algorithm to generate merger trees for two large simulations (Bolshoi and Consuelo) and evaluate two halo finders (ROCKSTAR and BDM). We find that both the ROCKSTAR and BDM halo finders track halos extremely well; in both, the number of halos which do not have physically consistent progenitors is at the 1%-2% level across all halo masses. Our code is publicly available at http://code.google.com/p/consistent-trees. Our trees and catalogs are publicly available at http://hipacc.ucsc.edu/Bolshoi/.

  3. Halo Intrinsic Alignment: Dependence on Mass, Formation Time, and Environment

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Qianli; Kang, Xi; Wang, Peng; Luo, Yu [Purple Mountain Observatory, the Partner Group of MPI für Astronomie, 2 West Beijing Road, Nanjing 210008 (China); Yang, Xiaohu; Jing, Yipeng [Center for Astronomy and Astrophysics, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Huiyuan [Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Mo, Houjun, E-mail: kangxi@pmo.ac.cn [Astronomy Department and Center for Astrophysics, Tsinghua University, Beijing 10084 (China)

    2017-10-10

    In this paper we use high-resolution cosmological simulations to study halo intrinsic alignment and its dependence on mass, formation time, and large-scale environment. In agreement with previous studies using N -body simulations, it is found that massive halos have stronger alignment. For the first time, we find that for a given halo mass older halos have stronger alignment and halos in cluster regions also have stronger alignment than those in filaments. To model these dependencies, we extend the linear alignment model with inclusion of halo bias and find that the halo alignment with its mass and formation time dependence can be explained by halo bias. However, the model cannot account for the environment dependence, as it is found that halo bias is lower in clusters and higher in filaments. Our results suggest that halo bias and environment are independent factors in determining halo alignment. We also study the halo alignment correlation function and find that halos are strongly clustered along their major axes and less clustered along the minor axes. The correlated halo alignment can extend to scales as large as 100 h {sup −1} Mpc, where its feature is mainly driven by the baryon acoustic oscillation effect.

  4. Mean size among the particles of short-lived radon daughter products in the atmosphere

    International Nuclear Information System (INIS)

    Nakatani, S.

    1980-01-01

    The diffusion-battery method is used to classify the radioactive particles according to their sizes. The diffusion coefficient is determined from the fractional penetration of the particles through the battery. Particle radii are derived from the diffusion coefficients with the Stokes-Cunningham-Millikan formula. At the exit and entrance of the battery, individual concentrations of radon daughter products 218 Po, 214 Pb, 214 Bi are determined. Thus the mean sizes of individual radon daughters can be obtained from the fractional penetration of individual nuclides through the diffusion battery. Despite large statistical fluctuations the mean size of 214 Bi is always shifted toward the larger size region as compared with those of other radionuclides

  5. Finite-width effects in unstable-particle production at hadron colliders

    International Nuclear Information System (INIS)

    Falgari, P.; Signer, A.; Zuerich Univ.

    2013-03-01

    We present a general formalism for the calculation of finite-width contributions to the differential production cross sections of unstable particles at hadron colliders. In this formalism, which employs an effective-theory description of unstable-particle production and decay, the matrix element computation is organized as a gauge-invariant expansion in powers of Γ X /m X , with Γ X and m X the width and mass of the unstable particle. This framework allows for a systematic inclusion of off-shell and non-factorizable effects whilst at the same time keeping the computational effort minimal compared to a full calculation in the complex-mass scheme. As a proof-of-concept example, we give results for an NLO calculation of top-antitop production in the q anti q partonic channel. As already found in a similar calculation of single-top production, the finite-width effects are small for the total cross section, as expected from the naive counting ∝Γ t /m t ∝1%. However, they can be sizeable, in excess of 10%, close to edges of certain kinematical distributions. The dependence of the results on the mass renormalization scheme, and its implication for a precise extraction of the top-quark mass, is also discussed.

  6. Finite-width effects in unstable-particle production at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Falgari, P. [Utrecht Univ. (Netherlands). Inst. for Theoretical Physics; Utrecht Univ. (Netherlands). Spinoza Inst.; Papanastasiou, A.S. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Signer, A. [Paul Scherrer Institut, Villigen (Switzerland); Zuerich Univ. (Switzerland). Inst. for Theoretical Physics

    2013-03-15

    We present a general formalism for the calculation of finite-width contributions to the differential production cross sections of unstable particles at hadron colliders. In this formalism, which employs an effective-theory description of unstable-particle production and decay, the matrix element computation is organized as a gauge-invariant expansion in powers of {Gamma}{sub X}/m{sub X}, with {Gamma}{sub X} and m{sub X} the width and mass of the unstable particle. This framework allows for a systematic inclusion of off-shell and non-factorizable effects whilst at the same time keeping the computational effort minimal compared to a full calculation in the complex-mass scheme. As a proof-of-concept example, we give results for an NLO calculation of top-antitop production in the q anti q partonic channel. As already found in a similar calculation of single-top production, the finite-width effects are small for the total cross section, as expected from the naive counting {proportional_to}{Gamma}{sub t}/m{sub t}{proportional_to}1%. However, they can be sizeable, in excess of 10%, close to edges of certain kinematical distributions. The dependence of the results on the mass renormalization scheme, and its implication for a precise extraction of the top-quark mass, is also discussed.

  7. A Study of Particle Production in Proton Induced Collisions Using the MIPP Detector at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Mahajan, Sonam [Panjab Univ., Chandigarh (India)

    2015-01-01

    The Main Injector Particle Production (MIPP) experiment is a fixed target hadron production experiment at Fermilab. MIPP is a high acceptance spectrometer which provides excellent charged particle identification using Time Projection Chamber (TPC), Time of Flight (ToF), multicell Cherenkov (Ckov), ring imaging Cherenkov (RICH) detectors, and Calorimeter for neutrons. The MIPP experiment is designed to measure particle production in interactions of 120 GeV/c primary protons from the Main Injector and secondary beams of $\\pi^{\\pm}, \\rm{K}^{\\pm}$, p and $\\bar{\\rm{p}}$ from 5 to 90 GeV/c on nuclear targets which include H, Be, C, Bi and U, and a dedicated run with the NuMI target. The goal of the experiment is to measure hadron production cross sections or yields using these beams and targets. These hadronic interaction data can have a direct impact on the detailed understanding of the neutrino fluxes of several accelerator-based neutrino experiments like MINOS, MINER$\

  8. Beam halo in high-intensity hadron linacs

    Energy Technology Data Exchange (ETDEWEB)

    Gerigk, F

    2006-12-21

    This document aims to cover the most relevant mechanisms for the development of beam halo in high-intensity hadron linacs. The introduction outlines the various applications of high-intensity linacs and it will explain why, in the case of the CERN Superconducting Proton Linac (SPL) study a linac was chosen to provide a high-power beam, rather than a different kind of accelerator. The basic equations, needed for the understanding of halo development are derived and employed to study the effects of initial and distributed mismatch on high-current beams. The basic concepts of the particle-core model, envelope modes, parametric resonances, the free-energy approach, and the idea of core-core resonances are introduced and extended to study beams in realistic linac lattices. The approach taken is to study the behavior of beams not only in simplified theoretical focusing structures but to highlight the beam dynamics in realistic accelerators. All effects which are described and derived with simplified analytic models, are tested in realistic lattices and are thus related to observable effects in linear accelerators. This approach involves the use of high-performance particle tracking codes, which are needed to simulate the behavior of the outermost particles in distributions of up to 100 million macro particles. In the end a set of design rules are established and their impact on the design of a typical high-intensity machine, the CERN SPL, is shown. The examples given in this document refer to two different design evolutions of the SPL study: the first conceptual design report (SPL I) and the second conceptual design report (SPL II). (orig.)

  9. RHAPSODY. I. STRUCTURAL PROPERTIES AND FORMATION HISTORY FROM A STATISTICAL SAMPLE OF RE-SIMULATED CLUSTER-SIZE HALOS

    International Nuclear Information System (INIS)

    Wu, Hao-Yi; Hahn, Oliver; Wechsler, Risa H.; Mao, Yao-Yuan; Behroozi, Peter S.

    2013-01-01

    We present the first results from the RHAPSODY cluster re-simulation project: a sample of 96 'zoom-in' simulations of dark matter halos of 10 14.8±0.05 h –1 M ☉ , selected from a 1 h –3 Gpc 3 volume. This simulation suite is the first to resolve this many halos with ∼5 × 10 6 particles per halo in the cluster mass regime, allowing us to statistically characterize the distribution of and correlation between halo properties at fixed mass. We focus on the properties of the main halos and how they are affected by formation history, which we track back to z = 12, over five decades in mass. We give particular attention to the impact of the formation history on the density profiles of the halos. We find that the deviations from the Navarro-Frenk-White (NFW) model and the Einasto model depend on formation time. Late-forming halos tend to have considerable deviations from both models, partly due to the presence of massive subhalos, while early-forming halos deviate less but still significantly from the NFW model and are better described by the Einasto model. We find that the halo shapes depend only moderately on formation time. Departure from spherical symmetry impacts the density profiles through the anisotropic distribution of massive subhalos. Further evidence of the impact of subhalos is provided by analyzing the phase-space structure. A detailed analysis of the properties of the subhalo population in RHAPSODY is presented in a companion paper.

  10. Fatty acid biosynthesis is involved in the production of hepatitis B virus particles

    International Nuclear Information System (INIS)

    Okamura, Hitomi; Nio, Yasunori; Akahori, Yuichi; Kim, Sulyi; Watashi, Koichi; Wakita, Takaji; Hijikata, Makoto

    2016-01-01

    Hepatitis B virus (HBV) proliferates in hepatocytes after infection, but the host factors that contribute to the HBV lifecycle are poorly understood at the molecular level. We investigated whether fatty acid biosynthesis (FABS), which was recently reported to contribute to the genomic replication of hepatitis C virus, plays a role in HBV proliferation. We examined the effects of inhibitors of the enzymes in the FABS pathway on the HBV lifecycle by using recombinant HBV-producing cultured cells and found that the extracellular HBV DNA level, reflecting HBV particle production, was decreased by treatment with inhibitors suppressed the synthesis of long-chain saturated fatty acids with little cytotoxicity. The reduced HBV DNA level was reversed when palmitic acid, which is the product of fatty acid synthase (FAS) during FABS, was used simultaneously with the inhibitor. We also observed that the amount of intracellular HBV DNA in the cells was increased by FAS inhibitor treatment, suggesting that FABS is associated with HBV particle production but not its genome replication. This suggests that FABS might be a potent target for anti-HBV drug with a mode of action different from current HBV therapy. -- Highlights: •Inhibitors of ACC1 and FAS but not SCD1 decreased production of extracellular HBV DNA. •Products of FABS, long chain fatty acids, increased production of extracellular HBV DNA. •FAS inhibitor increased intracellular levels of HBV DNA and HBcAg. •FABS was suggested to contribute to HBV particle production without significant relation with secretory pathway of the cells.

  11. Fatty acid biosynthesis is involved in the production of hepatitis B virus particles

    Energy Technology Data Exchange (ETDEWEB)

    Okamura, Hitomi [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyoku, Kyoto 606-8501 (Japan); Nio, Yasunori, E-mail: yasunori.nio@takeda.com [Takeda Pharmaceutical Company Limited, Pharmaceutical Research Division, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555 (Japan); Akahori, Yuichi [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyoku, Kyoto 606-8501 (Japan); Kim, Sulyi [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Watashi, Koichi [Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640 (Japan); Department of Applied Biological Science, Tokyo University of Sciences, Noda 278-8510 (Japan); CREST, Japan Science and Technology Agency (JST), Saitama 332-0012 (Japan); Wakita, Takaji [Department of Virology II, National Institute of Infectious Diseases, Tokyo 162-8640 (Japan); Hijikata, Makoto, E-mail: mhijikat@virus.kyoto-u.ac.jp [Laboratory of Human Tumor Viruses, Institute for Virus Research, Kyoto University, 53 Kawaharacho, Shogoin, Sakyoku, Kyoto 606-8507 (Japan); Graduate School of Biostudies, Kyoto University, Yoshida-Konoecho, Sakyoku, Kyoto 606-8501 (Japan)

    2016-06-17

    Hepatitis B virus (HBV) proliferates in hepatocytes after infection, but the host factors that contribute to the HBV lifecycle are poorly understood at the molecular level. We investigated whether fatty acid biosynthesis (FABS), which was recently reported to contribute to the genomic replication of hepatitis C virus, plays a role in HBV proliferation. We examined the effects of inhibitors of the enzymes in the FABS pathway on the HBV lifecycle by using recombinant HBV-producing cultured cells and found that the extracellular HBV DNA level, reflecting HBV particle production, was decreased by treatment with inhibitors suppressed the synthesis of long-chain saturated fatty acids with little cytotoxicity. The reduced HBV DNA level was reversed when palmitic acid, which is the product of fatty acid synthase (FAS) during FABS, was used simultaneously with the inhibitor. We also observed that the amount of intracellular HBV DNA in the cells was increased by FAS inhibitor treatment, suggesting that FABS is associated with HBV particle production but not its genome replication. This suggests that FABS might be a potent target for anti-HBV drug with a mode of action different from current HBV therapy. -- Highlights: •Inhibitors of ACC1 and FAS but not SCD1 decreased production of extracellular HBV DNA. •Products of FABS, long chain fatty acids, increased production of extracellular HBV DNA. •FAS inhibitor increased intracellular levels of HBV DNA and HBcAg. •FABS was suggested to contribute to HBV particle production without significant relation with secretory pathway of the cells.

  12. Study of strange particle production in jets with the ALICE experiment at the LHC

    CERN Document Server

    AUTHOR|(CDS)2082140; Kuhn, Christian

    Quark–gluon plasma is a state of matter existing under extreme energy densities and temperatures where quarks and gluons are deconfined. Complex phenomena occurring in the plasma emerge from the strong interaction of its constituents. This hot and dense strongly interacting matter can be created in ultra-relativistic heavy-ion collisions and its properties can be studied by measuring particles produced in the collisions. Partons produced in hard scatterings interact with the medium which modifies the production of particles in jets. Measurements of spectra of identified particles produced in jets represent an important tool for understanding the interplay of various hadronization mechanisms which contribute to the particle production in the medium created in heavy-ion collisions. In this thesis, we present the measurement of the $p_\\text{T}$ spectra of Λ baryons and $\\text{K}^{\\text{0}}_{\\text{S}}$ mesons produced in charged jets in central Pb–Pb collisions at the energy $\\sqrt{s_{\\text{NN}}} = 2.76\\ \\te...

  13. Phenomenology of the minimal inflation scenario: inflationary trajectories and particle production

    CERN Document Server

    Alvarez-Gaume, Luis; Jimenez, Raul

    2012-01-01

    We discuss the phenomenology of the minimal inflation scenario. We concentrate on two aspects: inflationary trajectories and particle production. Our findings can be summarized in two main results: first, that inflationary trayectories that are very flat and provide enough number of e-foldings are very natural in the scenario without fine tunning. We present a general formalism to identify attractors in multi-field inflation regardless of trajectories fulfilling the slow-roll conditions. We then explore particle production in the model and show how the inflaton naturally transmutes into the current dark matter particle, thus providing a mechanism to identify the inflaton today: it is the dark matter. One interesting feature of our model is that it provides a novel mechanism to generate particles and entropy in the universe: the filling of the Fermi sphere up to a given momentum pF due to the sea of goldstinos that are an important part of the matter generated after inflation. With this mechanism in hand we pr...

  14. Smooth halos in the cosmic web

    International Nuclear Information System (INIS)

    Gaite, José

    2015-01-01

    Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of inequality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in cold dark matter N-body simulations. These entropic measures provide us with a quantitative description of the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these ''smoothness sizes'' have no direct relation to the virial radii. Finally, we discuss the influence of N-body discreteness parameters on smoothness

  15. MAPPING THE GALACTIC HALO. VIII. QUANTIFYING SUBSTRUCTURE

    International Nuclear Information System (INIS)

    Starkenburg, Else; Helmi, Amina; Van Woerden, Hugo; Morrison, Heather L.; Harding, Paul; Frey, Lucy; Oravetz, Dan; Mateo, Mario; Dohm-Palmer, R. C.; Olszewski, Edward W.; Sivarani, Thirupathi; Norris, John E.; Freeman, Kenneth C.; Shectman, Stephen A.

    2009-01-01

    We have measured the amount of kinematic substructure in the Galactic halo using the final data set from the Spaghetti project, a pencil-beam high-latitude sky survey. Our sample contains 101 photometrically selected and spectroscopically confirmed giants with accurate distance, radial velocity, and metallicity information. We have developed a new clustering estimator: the '4distance' measure, which when applied to our data set leads to the identification of one group and seven pairs of clumped stars. The group, with six members, can confidently be matched to tidal debris of the Sagittarius dwarf galaxy. Two pairs match the properties of known Virgo structures. Using models of the disruption of Sagittarius in Galactic potentials with different degrees of dark halo flattening, we show that this favors a spherical or prolate halo shape, as demonstrated by Newberg et al. using the Sloan Digital Sky Survey data. One additional pair can be linked to older Sagittarius debris. We find that 20% of the stars in the Spaghetti data set are in substructures. From comparison with random data sets, we derive a very conservative lower limit of 10% to the amount of substructure in the halo. However, comparison to numerical simulations shows that our results are also consistent with a halo entirely built up from disrupted satellites, provided that the dominating features are relatively broad due to early merging or relatively heavy progenitor satellites.

  16. Smooth halos in the cosmic web

    Energy Technology Data Exchange (ETDEWEB)

    Gaite, José, E-mail: jose.gaite@upm.es [Physics Dept., ETSIAE, IDR, Universidad Politécnica de Madrid, Pza. Cardenal Cisneros 3, E-28040 Madrid (Spain)

    2015-04-01

    Dark matter halos can be defined as smooth distributions of dark matter placed in a non-smooth cosmic web structure. This definition of halos demands a precise definition of smoothness and a characterization of the manner in which the transition from smooth halos to the cosmic web takes place. We introduce entropic measures of smoothness, related to measures of inequality previously used in economy and with the advantage of being connected with standard methods of multifractal analysis already used for characterizing the cosmic web structure in cold dark matter N-body simulations. These entropic measures provide us with a quantitative description of the transition from the small scales portrayed as a distribution of halos to the larger scales portrayed as a cosmic web and, therefore, allow us to assign definite sizes to halos. However, these ''smoothness sizes'' have no direct relation to the virial radii. Finally, we discuss the influence of N-body discreteness parameters on smoothness.

  17. Multiple sampling ionization chamber (MUSIC) for investigation of fusion induced by halo nuclei

    International Nuclear Information System (INIS)

    Petrascu, H.; Kumagai, H.; Tanihata, I.; Fueloep, Zs.; Petrascu, M.

    1999-01-01

    A high resolution MUSIC for low and medium energy ions up to ∼ 20 AMeV, for investigation of fusion processes induced by halo nuclei, has been achieved. The chamber was used in the first experiments, aiming at investigating fusion processes induced by 9,11 Li with light targets. In these experiments MUSIC was used for the identification of the inclusive evaporation residues produced in the Si detector target, mounted inside the chamber. By using MUSIC it was possible to separate the inclusive spectra corresponding to the fusion processes, from the background due to the energy degraded beam particles. In principle such a chamber could be also used for investigation of particular fusion channels produced in the entrance window. In this case one could obtain the fusion product trajectory angle with the horizontal plane, by coupling each anode pad to a TDC. The chamber was also provided by a position grid, mounted between the Frisch grid and the anode pads. The energy loss distribution widths were measured using α particles. The chamber was filled with P-10 gas at pressures between 200 and 300 torr. The obtained resolution corresponding to a single pad, is close to the limit derived from the theory of Badhwar. (authors)

  18. Production of charmed particles in nuN collisions due to neutral weak currents

    International Nuclear Information System (INIS)

    Rekalo, M.P.

    1980-01-01

    A study is made of associated production of charmed particles in neutrino-nucleon interactions due to neutral weak currents. The angular distribution of the jets of charmed hadrons in nN interactions is determined in the lowest approximation in the quark-gluon coupling constant, according to which a charmed quark and antiquark are produced in an annihilation of a vector gluon and a virtual Z boson. It is shown that only a P-even dependence on the azimuthal angle v occurs in the studied approximation, the P-odd dependence which is possible in the general case being equal to zero. The total cross section for charmed-particle production in neutrino-nucleon interactions is calculated, and the origin of the violation of scale invariance is demonstrated

  19. Measurement of strange particle production in the NICA fixed-target programme

    Energy Technology Data Exchange (ETDEWEB)

    Friese, Volker [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2016-08-15

    Strange particles provide a sensitive tool to study the dense and hot matter created in relativistic nuclear collisions. Although strangeness production in such collisions has been a topic of experimental and theoretical research for many years, its understanding is far from being complete. This holds in particular for multi-strange hyperons and for lower collision energies as relevant for NICA and FAIR. Multi-strange particles, being sensitive to both the mechanism of strangeness production and the net-baryon density, are expected to shed light on the state of the created matter and to indicate possible transitions to new phases of strongly interacting matter. We thus advocate the measurement of hyperons and φ mesons in a fixed-target experiment at NICA (BM rate at N), which can be achieved by a relatively compact detector system. (orig.)

  20. Neutron-induced particle production in the cumulative and noncumulative regions at intermediate energies

    International Nuclear Information System (INIS)

    Mashnik, S.G.

    1992-01-01

    The first systematic measurements of neutron-induced inclusive production of protons, deuterons, tritons and charged pions on carbon, copper, and bismuth in the bombarding energy range of 300-580 MeV and in the angular interval from 51 deg to 165 deg have been analyzed in the framework of the cascade-exciton model. The role of single-particle scattering, the effects of rescattering, the pre-equilibrium emission and 'coalescence' mechanism in particle production in the cumulative (i.e., kinematically - forbidden for quasi-free intranuclear projectile-nucleon collisions) and noncumulative regions are discussed. A week sensitivity of the inclusive distributions to the specific reaction mechanisms and a need of correlation and polarization measurements are noted. 27 refs.; 12 figs.; 1 tab

  1. Alpha particles emitted from the surface of granite, clay, and its fired products, 1

    International Nuclear Information System (INIS)

    Aratani, Michi; Otsuka, Hideko

    1975-01-01

    As a part of an investigation on ''the effect of long-time irradiation from a trace amount of radioisotopes'', the emitting rate of alpha particles per unit surface area (apparent) coming from natural alpha-particle emitters has been measured. The samples measured were granite and its weathered product; clay, especially potter's clay, and its fired product; pottery ware. The values obtained were 39.1 +-0.9--0.73+-0.08 cpm/100 cm 2 in granite, 16.8+-0.4--6.4+-0.2 cpm/100cm 2 in potter's clay, and 1.36+-0.04--0.82+-0.04 cpm/100cm 2 in pottery ware on substrate, and 1.33+-0.05--0.32+-0.02 cpm/100cm 2 on glazer. (auth.)

  2. Production of neutrinos and neutrino-like particles in proton-nucleus interactions. [400 GeV, cross sections

    Energy Technology Data Exchange (ETDEWEB)

    Dishaw, J.P.

    1979-03-01

    An experimental search was performed to look for the direct production of neutrinos or neutrino-like particles, i.e., neutral particles which interact weakly with hadrons, in proton-nucleus interactions at 400 GeV incident proton energy. Possible sources of such particles include the semi-leptonic decay of new heavy particles such as charm, and the direct production of a light neutral Higgs particle such as the axion. The production of these particles has been inferred in this experiment by energy nonconservation in the collision of a proton with an iron nucleus. The total visible energy of the interaction was measured using a sampling ionization calorimeter. After correcting for beam intensity effects and cutting the data to eliminate systematic effects in the measurement, the final resolution of the calorimeter was 3.51% and increased with decreasing incident beam energy with a square root dependence on the beam energy. Energy nonconservation in the data is manifest as a non-Gaussian distribution on the low side of the calorimeter measured energy. Model calculations yield the fraction of events expected in this non-Gaussian behavior for the various sources of neutrinos or neutrino-like particles. A maximum likelihood fit to the data with the theoretical fraction of events expected yields the 95% confidence level production cross section upper limit values. The upper limits for general production of neutrino-like particles for various parameterizations of the production cross section are presented. The following specific upper limits have been established: charm particle production < 670 ..mu..barns, supersymmetric particle production carrying an additional quantum number R < 33 ..mu..barns (mass of 1 GeV), 8 ..mu..barns (mass of 3 GeV); axion production < 10/sup -3/ times the ..pi../sup 0/ production cross section. 144 references.

  3. Issues in leading particle and charm production in DIS at HERA

    International Nuclear Information System (INIS)

    Chekanov, S. V.

    1999-01-01

    A Monte Carlo simulation based on Ο(α s ) QCD matrix elements matched to parton showers shows that final-state hadrons in DIS can be used to tag events with a single (anti)quark recoiled against the proton. The method is particularly suited to study the mean charge of leading particles, which is sensitive to fragmentation and sea quark contribution to the proton structure function. They also discuss methods to study the charm production in DIS using the Breit frame

  4. Electromagnetic production of Higgs bosons, SUSY particles, glueballs and mesons in ultrarelativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Greiner, M.; Soff, G.

    1992-12-01

    The electromagnetic creation of various exotic particles in ultrarelativistic heavy-ion collisions is discussed. The production of intermediate mass Higgs bosons of the minimal supersymmetric extension of the Standard Model is enhanced over the Standard Model Higgs boson formation for certain model parameter choices and as a consequence might be detectable at LCH and SSC. We also investigate the electromagnetic generation of supersymmetric fermions and bosons as well as glueballs, mesons and fermions. (orig.)

  5. Multiple particles production for hadron-hadron reactions with finite hadronization time

    International Nuclear Information System (INIS)

    Arbex, N.

    1991-01-01

    Experimental data on multiple particle production for proton-proton reaction are analysed in the context of a very simple analytical model. The model exhibits the essential features of hydrodynamical calculations as, e.g., the formation of an intermediate object, which undergoes expansion. The simultaneous analysis of different types of data allows for the conclusion that such data reflect the dynamics of this intermediate object and have a very deem connection to the elementary processes. (author)

  6. J/psi particle production by 70 GeV/c protons

    International Nuclear Information System (INIS)

    Antipov, Yu.M.; Bessubov, V.A.; Bubanov, N.P.; Bushmin, Yu.B.; Denisov, S.P.; Gorin, Yu.P.; Lebedev, A.A.; Lednev, A.A.; Mikhailov, Yu.V.; Petrukhin, A.I.

    1975-01-01

    Invariant mass spectrum of μ + μ - pairs produced by 70 GeV/c protons in Be target are presented. Distinct enhancements in the mass region of rho, ω mesons, PHI meson and J/psi particle are observed. For J/psi production, x, ysup(*) and p 2 distributions are given. The total cross section for the reaction p + Be → (J/psi → μ + μ - ) + ... is equal to 9.5 +- 2.5 nb/nucleus

  7. SCALP: Scintillating ionization chamber for ALPha particle production in neutron induced reactions

    Science.gov (United States)

    Galhaut, B.; Durand, D.; Lecolley, F. R.; Ledoux, X.; Lehaut, G.; Manduci, L.; Mary, P.

    2017-09-01

    The SCALP collaboration has the ambition to build a scintillating ionization chamber in order to study and measure the cross section of the α-particle production in neutron induced reactions. More specifically on 16O and 19F targets. Using the deposited energy (ionization) and the time of flight measurement (scintillation) with a great accuracy, all the nuclear reaction taking part on this project will be identify.

  8. Study of diffusion processes in pumpkin particles during candied fruits production

    Directory of Open Access Journals (Sweden)

    V. Atamanyuk

    2017-12-01

    Full Text Available The production of candied fruits is a priority development area of the food industry. The basic process in candied fruits production is diffusion of sugar syrup into vegetable raw material. Kinetics of the diffusion processes depends on sucrose concentration, medium temperature, particles size and internal structure of the fruits.The experiments to determine the factors influencing the diffusion processes were carried out using the installation designed by the authors; the experimental dependences of sucrose concentration change in pumpkin candied fruits on time have been determined at temperatures of 20, 40, 60 and 80°C. Cell sizes and diameter of pores between the cells in raw and blanched pumpkin have been determined. This makes it possible to determine the internal porosity of the pumpkin particle, the value of which determines the coefficient of mass transfer.On the basis of the experiments we derived the dependence, allowing to determine the mass transfer coefficients for sucrose molecules in blanched pumpkin fruits within the temperatures corresponding to the quality of the finished product. The experimental studies and the chosen mathematical model allow us to calculate the change in sucrose concentration in the pumpkin fruits in time at different temperatures and to determine the time required for the candied fruits to reach the equilibrium concentration. Also, the coefficients not depending on temperature, but depending only on the shape of the particles being saturated with sugar syrup, have been determined using the kinetic model of diffusion processes. The obtained theoretical dependences are in good agreement with the experimental data and substantiate the expediency of the chosen temperature and concentration ranges. The designed installation, the obtained experimental and theoretical dependences, and the calculated coefficients allow to create an intensive sucrose diffusion process in pumpkin particles during pumpkin candied

  9. Measurements of Particle Production, Underlying Event and Double Parton Interactions at the LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00439671; The ATLAS collaboration

    2016-01-01

    The effects of soft, non-pertubative strong interactions (QCD) are an important part of the phenomenology of the events at hadron colliders, as the LHC. In order to constrain the parameters of models of soft QCD, diverse measurements are provided by the ALICE, ATLAS and CMS collaborations. Measurements of particle production, underlying event and double parton interactions are presented. In general, reasonable agreement between the measured data and the models is found, but discrepancies hint at the need for a better description.

  10. Resonance particle production in inelastic N-N and π-N interactions

    International Nuclear Information System (INIS)

    Amelin, N.S.; Barashenkov, V.S.; Slavin, N.V.

    1984-01-01

    Using the considerations connected with the scaling hypothesis and the Regge pole model the phenomenological expressions are obtained for differential single-particle inclusive production cross sections (Δ + , Δ 0 , Δ ++ ) and (p +- , p 0 , ω) resonances in inelastic π-N and N-N collisions at high energies. These expressions describe the known experimental data in a wide region of kinematic variables from 10 to several thousand GeV

  11. Production of massless particles in collisions of strings at high energy

    International Nuclear Information System (INIS)

    Lipatov, L.N.

    1988-01-01

    The authors obtain explicit formulas (generalizing the Low-Gribov expressions) for the production amplitude of massless particles (gluons and gravitons) with low transverse momenta in the scattering of lower-mass excitations of open and closed strings. In the limit α' → 0 they reproduce the results of calculation of effective vertices for inelastic scattering amplitudes in multi-Regge kinematics in the Yang-Mills theory and in gravitation

  12. Improvement in retention of solid fission products in HTGR fuel particles by ceramic kernel additives

    Energy Technology Data Exchange (ETDEWEB)

    Foerthmann, R.; Groos, E.; Gruebmeier, H.

    1975-08-15

    Increased requirements concerning the retention of long-lived solid fission products in fuel elements for use in advanced High Temperature Gas-cooled Reactors led to the development of coated particles with improved fission product retention which represent an alternative to silicon carbide-coated fuel particles. Two irradiation experiments have shown that the release of strontium, barium, and caesium from pyrocarbon-coated particles can be reduced by orders of magnitude if the oxide kernel contains alumina-silica additives. It was detected by electron microprobe analysis that the improved retention of the mentioned fission products in the fuel kernel is caused by formation of the stable aluminosilicates SrAl2Si2O8, BaAl2Si2O8and CsAlSi2O6 in the additional alumina-silica phase of the kernel.

  13. Research on in-pile release of fission products from coated particle fuels

    International Nuclear Information System (INIS)

    Fukuda, K.; Iwamoto, K.

    1985-01-01

    Coated particle fuels fabricated in accordance with VHTR (Very High Temperature gas-cooled Reactor) fuel design have been irradiated by both capsules and an in-pile gas loop (OGL-1), and data on the fission products release under irradiation were obtained for loose coated particles, fuel compacts and fuel rods in the temperature range between 800 deg. C and 1600 deg. C. For the fission gases, temperature- and time dependences of the fractional release(R/B) were measured. Relation between release and failure fraction of the coated particles was elucidated on the VHTR reference fuels. Also measured was tritium concentration in the helium coolant of OGL-1. In-pile release behavior of the metallic fission products was studied by measuring the activities of the fission products adsorbed in the graphite sleeves of the OGL-1 fuel rods and the graphite fuel container of the sweep gas capsules in the PIE. Investigation on palladium interaction with SiC coating layer was included. (author)

  14. Characterization of Spatial Impact of Particles Emitted from a Cement Material Production Facility on Outdoor Particle Deposition in the Surrounding Community.

    Science.gov (United States)

    Yu, Chang Ho; Fan, Zhihua Tina; McCandlish, Elizabeth; Stern, Alan H; Lioy, Paul J

    2011-10-01

    The objective of this study was to estimate the contribution of a facility that processes steel production slag into raw material for cement production to local outdoor particle deposition in Camden, NJ. A dry deposition sampler that can house four 37-mm quartz fiber filters was developed and used for the collection of atmospheric particle deposits. Two rounds of particle collection (3-4 weeks each) were conducted in 8-11 locations 200-800 m downwind of the facility. Background samples were concurrently collected in a remote area located ∼2 km upwind from the facility. In addition, duplicate surface wipe samples were collected side-by-side from each of the 13 locations within the same sampling area during the first deposition sampling period. One composite source material sample was also collected from a pile stored in the facility. Both the bulk of the source material and the particle deposition flux in the study area was higher (24-83 mg/m 2 ·day) than at the background sites (13-17 mg/m 2 ·day). The concentration of Ca, a major element in the cement source production material, was found to exponentially decrease with increasing downwind distance from the facility (P particle deposition. The contribution of the facility to outdoor deposited particle mass was further estimated by three independent models using the measurements obtained from this study. The estimated contributions to particle deposition in the study area were 1.8-7.4% from the regression analysis of the Ca concentration in particle deposition samples against the distance from the facility, 0-11% from the U.S. Environmental Protection Agency (EPA) Chemical Mass Balance (CMB) source-receptor model, and 7.6-13% from the EPA Industrial Source Complex Short Term (ISCST3) dispersion model using the particle-size-adjusted permit-based emissions estimates. [Box: see text].

  15. Fission product behaviour - in particular Cs-137 - in HTR-TRISO-coated particle fuel

    International Nuclear Information System (INIS)

    Allelein, H.J.

    1980-12-01

    This work is performed between 1977 and 1979. The main task is to determine a temperature dependent diffusion coefficient of the fission product Cs-137 in the silicon carbide interlayer of HTR particles. The raw material is laso presented as the used measuring techniques and computer codes. The results are discussed in detail and some critical remarks are made about the efficiency of the silicon carbide interlayer to retent fission products including Ag-110m, Sr-90, and Ru-106, which temperature dependent diffusion coefficient is also been determined. (orig.) [de

  16. Hydrogen Production by a Hyperthermophilic Membrane-Bound Hydrogenase in Soluble Nanolipoprotein Particles

    Energy Technology Data Exchange (ETDEWEB)

    Baker, S E; Hopkins, R C; Blanchette, C; Walsworth, V; Sumbad, R; Fischer, N; Kuhn, E; Coleman, M; Chromy, B; Letant, S; Hoeprich, P; Adams, M W; Henderson, P T

    2008-10-22

    Hydrogenases constitute a promising class of enzymes for ex vivo hydrogen production. Implementation of such applications is currently hindered by oxygen sensitivity and, in the case of membrane-bound hydrogenases (MBH), poor water solubility. Nanolipoprotein particles (NLPs), formed from apolipoproteins and phospholipids, offer a novel means to incorporate MBH into in a well-defined water-soluble matrix that maintains the enzymatic activity and is amenable to incorporation into more complex architectures. We report the synthesis, hydrogen-evolving activity and physical characterization of the first MBH-NLP assembly. This may ultimately lead to the development of biomimetic hydrogen production devices.

  17. Particle production in high energy nucleus--nucleus experiments at Berkeley

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1976-09-01

    A review of high energy nucleus-nucleus experiments performed at the Berkeley Bevalac is presented. Earlier results on projectile and target fragmentation and pion production are briefly summarized. More recent results on Coulomb effects in projectile fragmentation, heavy ion total cross-sections, γ-ray production, and charged particle multiplicities are presented. Also, recent experiments which may shed light on phenomena arising from the central collision of two energetic nuclei, including recent evidence for and against the observation of nuclear shock waves, are reviewed

  18. Population II brown dwarfs and dark haloes

    International Nuclear Information System (INIS)

    Zinnecker, H.

    1986-01-01

    Opacity-limited fragmentation is investigated as a function of the dust-to-gas ratio and it is found that the characteristic protostellar mass Msub(*) is metallicity-dependent. This dependence is such that, for the low metallicity gas out of which the stars of Population II formed in the halo, Msub(*) is less than 0.1 M solar mass. If applicable, these theoretical considerations would predict that substellar masses have formed more frequently under the metal-poor conditions in the early Galaxy (Population II brown dwarfs). Thus the missing mass in the Galactic halo and in the dark haloes around other spirals may well reside in these metal-poor Population II brown dwarfs. (author)

  19. Beam halo in high-intensity beams

    International Nuclear Information System (INIS)

    Wangler, T.P.

    1993-01-01

    In space-charge dominated beams the nonlinear space-charge forces produce a filamentation pattern, which in projection to the 2-D phase spaces results in a 2-component beam consisting of an inner core and a diffuse outer halo. The beam-halo is of concern for a next generation of cw, high-power proton linacs that could be applied to intense neutron generators for nuclear materials processing. The author describes what has been learned about beam halo and the evolution of space-charge dominated beams using numerical simulations of initial laminar beams in uniform linear focusing channels. Initial results are presented from a study of beam entropy for an intense space-charge dominated beam

  20. Stability of BEC galactic dark matter halos

    Energy Technology Data Exchange (ETDEWEB)

    Guzmán, F.S.; Lora-Clavijo, F.D.; González-Avilés, J.J.; Rivera-Paleo, F.J., E-mail: guzman@ifm.umich.mx, E-mail: fadulora@ifm.umich.mx, E-mail: javiles@ifm.umich.mx, E-mail: friverap@ifm.umich.mx [Instituto de Física y Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio C-3, Cd. Universitaria, 58040 Morelia, Michoacán (Mexico)

    2013-09-01

    In this paper we show that spherically symmetric BEC dark matter halos, with the sin r/r density profile, that accurately fit galactic rotation curves and represent a potential solution to the cusp-core problem are unstable. We do this by introducing back the density profiles into the fully time-dependent Gross-Pitaevskii-Poisson system of equations. Using numerical methods to track the evolution of the system, we found that these galactic halos lose mass at an approximate rate of half of its mass in a time scale of dozens of Myr. We consider this time scale is enough as to consider these halos are unstable and unlikely to be formed. We provide some arguments to show that this behavior is general and discuss some other drawbacks of the model that restrict its viability.

  1. Chemical enrichment in halo planetary nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Peimbert, S; Rayo, J F; Peimbert, M [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    Photoelectric spectrophotometry of emission lines in the 3400-7400 A region is presented for the planetary nebulae 108-76/sup 0/1(BB1). From these observations the relative abundances of H, He, C, N, O and Ne are derived. The abundances of the halo PN (BB1, H4-1 and K648) are compared to those predicted by stellar evolution theory under the assumption that the envelope has the chemical composition of the matter located between the H burning shell and the surface. The observed He/H and C/O values are higher than predicted which implies that halo PN contain matter from deeper layers than the H burning shell. Furthermore, the O/Ar, N/Ar and Ne/Ar values in halo PN are higher than in the solar neighbourhood, at least part of this enrichment is produced by the PN progenitors.

  2. Vacuum Potentials for the Two Only Permanent Free Particles, Proton and Electron. Pair Productions

    International Nuclear Information System (INIS)

    Zheng-Johansson, J X

    2012-01-01

    The two only species of isolatable, smallest, or unit charges +e and −e present in nature interact with the universal vacuum in a polarisable dielectric representation through two uniquely defined vacuum potential functions. All of the non-composite subatomic particles containing one-unit charges, +e or −e, are therefore formed in terms of the IED model of the respective charges, of zero rest masses, oscillating in either of the two unique vacuum potential fields, together with the radiation waves of their own charges. In this paper we give a first principles treatment of the dynamics of charge in a dielectric vacuum, based on which, combined with solutions for the radiation waves obtained previously, we subsequently derive the vacuum potential function for a given charge q, which we show to be quadratic and consist each of quantised potential levels, giving therefore rise to quantised characteristic oscillation frequencies of the charge and accordingly quantised, sharply-defined masses of the IED particles. By further combining with relevant experimental properties as input information, we determine the IED particles built from the charges +e, −e at their first excited states in the respective vacuum potential wells to be the proton and the electron, the observationally two only stable (permanently lived) and 'free' particles containing one-unit charges. Their antiparticles as produced in pair productions can be accordingly determined. The characteristics of all of the other more energetic single-charged non-composite subatomic particles can also be recognised. We finally discuss the energy condition for pair production, which requires two successive energy supplies to (1) first disintegrate the bound pair of vaculeon charges +e, −e composing a vacuuon of the vacuum and (2) impart masses to the disintegrated charges.

  3. Galaxy halo occupation at high redshift

    Science.gov (United States)

    Bullock, James S.; Wechsler, Risa H.; Somerville, Rachel S.

    2002-01-01

    We discuss how current and future data on the clustering and number density of z~3 Lyman-break galaxies (LBGs) can be used to constrain their relationship to dark matter haloes. We explore a three-parameter model in which the number of LBGs per dark halo scales like a power law in the halo mass: N(M)=(M/M1)S for M>Mmin. Here, Mmin is the minimum mass halo that can host an LBG, M1 is a normalization parameter, associated with the mass above which haloes host more than one observed LBG, and S determines the strength of the mass-dependence. We show how these three parameters are constrained by three observable properties of LBGs: the number density, the large-scale bias and the fraction of objects in close pairs. Given these three quantities, the three unknown model parameters may be estimated analytically, allowing a full exploration of parameter space. As an example, we assume a ΛCDM cosmology and consider the observed properties of a recent sample of spectroscopically confirmed LBGs. We find that the favoured range for our model parameters is Mmin~=(0.4-8)×1010h- 1Msolar, M1~=(6-10)×1012h- 1Msolar, and 0.9acceptable if the allowed range of bg is permitted to span all recent observational estimates. We also discuss how the observed clustering of LBGs as a function of luminosity can be used to constrain halo occupation, although because of current observational uncertainties we are unable to reach any strong conclusions. Our methods and results can be used to constrain more realistic models that aim to derive the occupation function N(M) from first principles, and offer insight into how basic physical properties affect the observed properties of LBGs.

  4. DARK MATTER HALO MERGERS: DEPENDENCE ON ENVIRONMENT

    International Nuclear Information System (INIS)

    Hester, J. A.; Tasitsiomi, A.

    2010-01-01

    This paper presents a study of the specific major merger rate as a function of group membership, local environment, and redshift in a very large, 500 h -1 Mpc, cosmological N-body simulation, the Millennium Simulation. The goal is to provide environmental diagnostics of major merger populations in order to test simulations against observations and provide further constraints on major merger driven galaxy evolution scenarios. A halo sample is defined using the maximum circular velocity, which is both well defined for subhalos and closely correlated with galaxy luminosity. Subhalos, including the precursors of major mergers, are severely tidally stripped. Major mergers between subhalos are therefore rare compared to mergers between subhalos and their host halos. Tidal stripping also suppresses dynamical friction, resulting in long major merger timescales when the more massive merger progenitor does not host other subhalos. When other subhalos are present, however, major merger timescales are several times shorter. This enhancement may be due to inelastic unbound collisions between subhalos, which deplete their orbital angular momentum and lead to faster orbital decay. Following these results, we predict that major mergers in group environments are dominated by mergers involving the central galaxy, that the specific major merger rate is suppressed in groups when all group members are considered together, and that the frequency of fainter companions is enhanced for major mergers and their remnants. We also measure an 'assembly bias' in the specific major merger rate in that major mergers of galaxy-like halos are slightly suppressed in overdense environments while major mergers of group-like halos are slightly enhanced. A dynamical explanation for this trend is advanced which calls on both tidal effects and interactions between bound halos beyond the virial radii of locally dynamically dominant halos.

  5. Cost Minimization for Joint Energy Management and Production Scheduling Using Particle Swarm Optimization

    Science.gov (United States)

    Shah, Rahul H.

    production planning framework are discussed. A modified Particle Swarm Optimization solution technique is adopted to solve the proposed scheduling problem. The algorithm is described in detail and compared to Genetic Algorithm. Case studies are presented to illustrate the benefits of using the proposed model and the effectiveness of the Particle Swarm Optimization approach. Numerical Experiments are implemented and analyzed to test the effectiveness of the proposed model. The proposed scheduling strategy can achieve savings of around 19 to 27 % in cost per part when compared to the baseline scheduling scenarios. By optimizing key production system parameters from the cost per part model, the baseline scenarios can obtain around 20 to 35 % in savings for the cost per part. These savings further increase by 42 to 55 % when system parameter optimization is integrated with the proposed scheduling problem. Using this method, the most influential parameters on the cost per part are the rated power from production, the production rate, and the initial machine reliabilities. The modified Particle Swarm Optimization algorithm adopted allows greater diversity and exploration compared to Genetic Algorithm for the proposed joint model which results in it being more computationally efficient in determining the optimal scheduling. While Genetic Algorithm could achieve a solution quality of 2,279.63 at an expense of 2,300 seconds in computational effort. In comparison, the proposed Particle Swarm Optimization algorithm achieved a solution quality of 2,167.26 in less than half the computation effort which is required by Genetic Algorithm.

  6. Radio halo sources in clusters of galaxies

    International Nuclear Information System (INIS)

    Hanisch, R.J.

    1986-01-01

    Radio halo sources remain one of the most enigmatic of all phenomena related to radio emission from galaxies in clusters. The morphology, extent, and spectral structure of these sources are not well known, and the models proposed to explain them suffer from this lack of observational detail. However, recent observations suggest that radio halo sources may be a composite of relic radio galaxies. The validity of this model could be tested using current and planned high resolutions, low-frequency radio telescopes. 31 references

  7. Blazars with arcminute-scale radio halos

    International Nuclear Information System (INIS)

    Ulvestad, J.S.; Antonucci, R.R.J.; Space Telescope Science Institute, Baltimore, MD)

    1986-01-01

    About 10-arcsec resolution 20-cm wavelength maps are presented for three nearby BL Lac objects: Mkn 180, whose halo has a linear size of 85 kpc, 2155-304, with a halo about 375 kpc across, and 1727 + 502, whose one-sided diffuse emission extends to a distance of about 145 kpc from its radio core. Little evidence is found for strong radio variability in the cores of the three blazars; these and other results obtained are consistent with the assertion that the three objects should be classified as normal low luminosity double radio galaxies with optically dull nuclei, if seen from other directions. 20 references

  8. Dark energy and extended dark matter halos

    Science.gov (United States)

    Chernin, A. D.; Teerikorpi, P.; Valtonen, M. J.; Dolgachev, V. P.; Domozhilova, L. M.; Byrd, G. G.

    2012-03-01

    The cosmological mean matter (dark and baryonic) density measured in the units of the critical density is Ωm = 0.27. Independently, the local mean density is estimated to be Ωloc = 0.08-0.23 from recent data on galaxy groups at redshifts up to z = 0.01-0.03 (as published by Crook et al. 2007, ApJ, 655, 790 and Makarov & Karachentsev 2011, MNRAS, 412, 2498). If the lower values of Ωloc are reliable, as Makarov & Karachentsev and some other observers prefer, does this mean that the Local Universe of 100-300 Mpc across is an underdensity in the cosmic matter distribution? Or could it nevertheless be representative of the mean cosmic density or even be an overdensity due to the Local Supercluster therein. We focus on dark matter halos of groups of galaxies and check how much dark mass the invisible outer layers of the halos are able to host. The outer layers are usually devoid of bright galaxies and cannot be seen at large distances. The key factor which bounds the size of an isolated halo is the local antigravity produced by the omnipresent background of dark energy. A gravitationally bound halo does not extend beyond the zero-gravity surface where the gravity of matter and the antigravity of dark energy balance, thus defining a natural upper size of a system. We use our theory of local dynamical effects of dark energy to estimate the maximal sizes and masses of the extended dark halos. Using data from three recent catalogs of galaxy groups, we show that the calculated mass bounds conform with the assumption that a significant amount of dark matter is located in the invisible outer parts of the extended halos, sufficient to fill the gap between the observed and expected local matter density. Nearby groups of galaxies and the Virgo cluster have dark halos which seem to extend up to their zero-gravity surfaces. If the extended halo is a common feature of gravitationally bound systems on scales of galaxy groups and clusters, the Local Universe could be typical or even

  9. The Production of FRW Universe and Decay to Particles in Multiverse

    Science.gov (United States)

    Ghaffary, Tooraj

    2017-09-01

    In this study, first, it will be shown that as the Hubble parameter, " H", increases the production cross section for closed and flat Universes increases rapidly at smaller values of " H" and becomes constant for higher values of " H". However in the case of open Universe, the production cross section has been encountered a singularity. Before this singularity, as the H parameter increases, the cross section increases, for smaller H, ( H < 2.5), exhibits a turn-over at moderate values of H, (2.5 < H < 3.5), decreases for larger amount of H After that and for a special value of H, the cross section has been encountered with a singularity. Although the cross section cannot be defined at this singularity but before and after this point, it is certainly equal to zero. After this singularity, the cross section increases rapidly, when H increases. It is shown that if the production cross section of Universe happens before this singularity, it can't achieve to higher values of Hubble parameter after singularity. More over if the production cross section of Universe situates after the singularity, it won't get access to values of Hubble parameter less than the singularity. After that the thermal distribution for particles inside the FRW Universes are obtained. It is found that a large amount of particles are produced near apparent horizon due to their variety in their energy and their probabilities. Finally, comparing the particle production cross sections for flat, closed and open Universes, it is concluded that as the value of k increases, the cross section decreases.

  10. Irradiation performance of coated fuel particles with fission product retaining kernel additives

    International Nuclear Information System (INIS)

    Foerthmann, R.

    1979-10-01

    The four irradiation experiments FRJ2-P17, FRJ2-P18, FRJ2-P19, and FRJ2-P20 for testing the efficiency of fission product-retaining kernel additives in coated fuel particles are described. The evaluation of the obtained experimental data led to the following results: - zirconia and alumina kernel additives are not suitable for an effective fission product retention in oxide fuel kernels, - alumina-silica kernel additives reduce the in-pile release of Sr 90 and Ba 140 from BISO-coated particles at temperatures of about 1200 0 C by two orders of magnitude, and the Cs release from kernels by one order of magnitude, - effective transport coefficients including all parameters which contribute to kernel release are given for (Th,U)O 2 mixed oxide kernels and low enriched UO 2 kernels containing 5 wt.% alumina-silica additives: 10g sub(K)/cm 2 s -1 = - 36 028/T + 6,261 (Sr 90), 10g Dsub(K)/cm 2 c -2 = - 29 646/T + 5,826 (Cs 134/137), alumina-silica kernel additives are ineffective for retaining Ag 110 m in coated particles. However, also an intact SiC-interlayer was found not to be effective at temperatures above 1200 0 C, - the penetration of the buffer layer by fission product containing eutectic additive melt during irradiation can be avoided by using additives which consist of alumina and mullite without an excess of silica, - annealing of LASER-failed irradiated particles and the irradiation test FRJ12-P20 indicate that the efficiency of alumina-silica kernel additives is not altered if the coating becomes defect. (orig.) [de

  11. Control of beam halo-chaos using fuzzy logic controller

    International Nuclear Information System (INIS)

    Gao Yuan; Yuan Haiying; Tan Guangxing; Luo Wenguang

    2012-01-01

    Considering the ion beam with initial K-V distribution in the periodic focusing magnetic filed channels (PFCs) as a typical sample, a fuzzy control method for control- ling beam halo-chaos was studied. A fuzzy proportional controller, using output of fuzzy inference as a control factor, was presented for adjusting exterior focusing magnetic field. The stability of controlled system was proved by fuzzy phase plane analysis. The simulation results demonstrate that the chaotic radius of envelope can be controlled to the matched radius via controlling magnetic field. This method was also applied to the multi-particle model. Under the control condition, the beam halos and its regeneration can be eliminated effectively, and that both the compactness and the uniformity of ion beam are improved evidently. Since the exterior magnetic field can be rather easily adjusted by proportional control and the fuzzy logic controller is independent to the mathematical model, this method has adaptive ability and is easily realized in experiment. The research offers a valuable reference for the design of the PFCs in the high- current linear ion accelerators. (authors)

  12. Production method of {alpha} particles; Une methode de production des particules {alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Prevot, F [Commissariat a l' Energie Atomique, Saclay(France). Centre d' Etudes Nucleaires

    1953-07-01

    It is proposed a method to get an intense beam of {alpha} particles. With a source of ordinary ions, we form a helium beam, once ionized, it is accelerated with an energy of a few hundreds of keV. While crossing a matter any that can be a thin leaf or a gaseous blade, the second electron of helium is pulled with a yield that only depends on the energy of the beam of helium and that is equal to 1/2 for 650 keV. (author) [French] Il est propose une methode pour obtenir un faisceau intense de particules {alpha}. Avec une source d'ions ordinaire, on forme un faisceau d'helium une fois ionise qu'on accelere avec une energie de quelques centaines de keV. En traversant une matiere quelconque qui peut etre sous forme de feuille mince ou de lame gazeuse, le deuxieme electron de l'helium est arrache avec un rendement qui ne depend que de l'energie du faisceau d'helium et qui vaut 1/2 pour 650 keV. (auteur)

  13. Charged Particle, Photon Multiplicity, and Transverse Energy Production in High-Energy Heavy-Ion Collisions

    Directory of Open Access Journals (Sweden)

    Raghunath Sahoo

    2015-01-01

    Full Text Available We review the charged particle and photon multiplicities and transverse energy production in heavy-ion collisions starting from few GeV to TeV energies. The experimental results of pseudorapidity distribution of charged particles and photons at different collision energies and centralities are discussed. We also discuss the hypothesis of limiting fragmentation and expansion dynamics using the Landau hydrodynamics and the underlying physics. Meanwhile, we present the estimation of initial energy density multiplied with formation time as a function of different collision energies and centralities. In the end, the transverse energy per charged particle in connection with the chemical freeze-out criteria is discussed. We invoke various models and phenomenological arguments to interpret and characterize the fireball created in heavy-ion collisions. This review overall provides a scope to understand the heavy-ion collision data and a possible formation of a deconfined phase of partons via the global observables like charged particles, photons, and the transverse energy measurement.

  14. Search for charged-particle d-d fusion products in an encapsulated Pd thin film

    International Nuclear Information System (INIS)

    Lopez, E.; Neuhauser, B.; Ziemba, F.; Jackson, J.; Mapoles, E.; McVittie, J.; Powell, R.

    1991-01-01

    Motivated by reports by Fleischmann and Pons and also Jones et al. of nuclear fusion occurring at room temperature, we attempted to look for charged particle reaction products from d-d fusion in a deuterated palladium thin film. A silicon nitride encapsulated palladium thin film (340 nanometers thick and one square centimeter in area) was fabricated on top of a semiconductor particle detector and implanted with an 80 keV D 2 + beam. The purpose of the nitride cap was to prevent deuterium from diffusing out or from being sputtered away during implantation. The detector temperature was maintained below 200 K in order to reduce pressure on the cap. During the first run of this experiment, after the ion implanter had been turned off, apparent charged particle pulses as well as bursts of activity in two nearby Geiger counters were observed with the film loaded to a nominal 150% deuterium-to-palladium ratio and a 1.3% does of 6 Li. No spectrum was obtained because of equipment malfunction. In a second run no apparent charged particles pulses were observed, but a record of the neutron flux due to induced fusion during implantation suggested that the nitride cap had failed. More experimental runs are expected in the near future

  15. Lattice QCD Thermodynamics and RHIC-BES Particle Production within Generic Nonextensive Statistics

    Science.gov (United States)

    Tawfik, Abdel Nasser

    2018-05-01

    The current status of implementing Tsallis (nonextensive) statistics on high-energy physics is briefly reviewed. The remarkably low freezeout-temperature, which apparently fails to reproduce the firstprinciple lattice QCD thermodynamics and the measured particle ratios, etc. is discussed. The present work suggests a novel interpretation for the so-called " Tsallis-temperature". It is proposed that the low Tsallis-temperature is due to incomplete implementation of Tsallis algebra though exponential and logarithmic functions to the high-energy particle-production. Substituting Tsallis algebra into grand-canonical partition-function of the hadron resonance gas model seems not assuring full incorporation of nonextensivity or correlations in that model. The statistics describing the phase-space volume, the number of states and the possible changes in the elementary cells should be rather modified due to interacting correlated subsystems, of which the phase-space is consisting. Alternatively, two asymptotic properties, each is associated with a scaling function, are utilized to classify a generalized entropy for such a system with large ensemble (produced particles) and strong correlations. Both scaling exponents define equivalence classes for all interacting and noninteracting systems and unambiguously characterize any statistical system in its thermodynamic limit. We conclude that the nature of lattice QCD simulations is apparently extensive and accordingly the Boltzmann-Gibbs statistics is fully fulfilled. Furthermore, we found that the ratios of various particle yields at extreme high and extreme low energies of RHIC-BES is likely nonextensive but not necessarily of Tsallis type.

  16. Production and detection of axion-like particles at the VUV-FEL. Letter of intent

    International Nuclear Information System (INIS)

    Koetz, U.; Ringwald, A.; Tschentscher, T.

    2006-06-01

    Recently, the PVLAS collaboration has reported evidence for an anomalously large rotation of the polarization of light generated in vacuum in the presence of a transverse magnetic field. This may be explained through the production of a new light spin-zero particle coupled to two photons. In this Letter of Intent, we propose to test this hypothesis by setting up a photon regeneration experiment which exploits the photon beam of the Vacuum-UltraViolet Free-Electron Laser VUV-FEL, sent along the transverse magnetic field of a linear arrangement of dipole magnets of size B L ∼ 30 Tm. The high photon energies available at the VUV-FEL increase substantially the expected photon regeneration rate in the mass range implied by the PVLAS anomaly, in comparison to the rate expected at visible lasers of similar power. We find that the particle interpretation of the PVLAS result can be tested within a short running period. The pseudoscalar vs. scalar nature can be determined by varying the direction of the magnetic field with respect to the laser polarization. The mass of the particle can be measured by running at different photon energies. The proposed experiment offers a window of opportunity for a firm establishment or exclusion of the particle interpretation of the PVLAS anomaly before other experiments can compete. (Orig.)

  17. Dynamical or static radio halo - Is there a galactic wind

    International Nuclear Information System (INIS)

    Lerche, I.; Schlickeiser, R.

    1981-01-01

    The effect of a galactic wind on a radio halo can be best observed at frequencies smaller than about 1 GHz. At higher frequencies static halo models predict the same features as dynamical halo models. External galaxies, which exhibit a break by 0.5 in their high frequency nonthermal integral flux spectrum, are the best candidates for studying the influence of galactic winds on the formation of relativistic electron haloes around these systems. Several such cases are presented

  18. Determination of nanoscale particles in the air of working zone at the metallurgical production

    Directory of Open Access Journals (Sweden)

    Т.S. Ulanova

    2015-03-01

    Full Text Available The results of studies of the air of working zone at the metallurgical production on the example of Avisma OJSC (Berezniki, the Perm Territory for the content of nanoscale particles are specified. The maximum nanoparticles concentration in the range of 13523–28609 mln./m3 is determined at the working place of the titanium production smelter with the maximum size of particles of 10–15 nm. At the working place in the administrative building (reference working place the maximum concentration is determined within the range of 524–1000 mln./m3; the maximum size of nanoparticles is 20 nm. It was established that the number concentration of nanoparticles at the reference working places (administration of Avisma OJSC is significantly lower than at the working places of main production processes. The presented studies can be used as the additional factors in the assessment of labor conditions and occupational risk during the manufacture and use of materials containing nanoparticles as well as the production processes with the nanoparticles formation.

  19. Inclusive charged particle production at large angles at the CERN ISR

    CERN Document Server

    Alper, B; Booth, P; Bulos, F; Carroll, L J; Damgaard, G; Duff, Brian G; Heymann, Franz F; Jackson, J N; Jarlskog, G; Jönsson, L B; Klovning, A; Leistam, L; Lillethun, E; Lynch, G; Manning, Geoffrey; Prentice, M; Quarrie, D; von Dardel, Guy F; Weiss, J M

    1973-01-01

    Three different sets of results are presented: 1. Data on the inclusive production of pi /sup +or-/, K/sup +or-/, p, and p, at low transverse momenta over an angular range of 29 degrees to 90 degrees in the centre-of-mass system and for centre-of-mass energies square root s=31 and 53 GeV. 2. Results from a search for massive particles at 62.5 degrees in the laboratory, square root s=53 GeV-in particular, cross-sections for the production of deuterons and antideuterons are given. 3. Data on inclusive charged particle production of high transverse momentum P/sub T/ between 1.5 and 4.4 GeV/c, at centre-of- mass angles 59.4 degrees and 90 degrees , square root s=44 and 53 GeV. In addition, preliminary measurements have been made at square root s =31 and 44 GeV of pi /sup +or-/, K/sup +or-/, p, and p production ratios at 90 degrees for p/sub T/ between 2.0 and 3.5 GeV.c. (14 refs) .

  20. Mass production of polymer nano-wires filled with metal nano-particles.

    Science.gov (United States)

    Lomadze, Nino; Kopyshev, Alexey; Bargheer, Matias; Wollgarten, Markus; Santer, Svetlana

    2017-08-17

    Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers. In this paper, we report on a technique for producing arrays of ordered, flexible and free-standing polymer nano-wires filled with different types of nano-particles. The process utilizes the strong response of photosensitive polymer brushes to irradiation with UV-interference patterns, resulting in a substantial mass redistribution of the polymer material along with local rupturing of polymer chains. The chains can wind up in wires of nano-scale thickness and a length of up to several centimeters. When dispersing nano-particles within the film, the final arrangement is similar to a core-shell geometry with mainly nano-particles found in the core region and the polymer forming a dielectric jacket.

  1. Radon decay products and 10–1100 nm aerosol particles in Postojna Cave

    Directory of Open Access Journals (Sweden)

    M. Bezek

    2013-03-01

    Full Text Available At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn decay products and the number concentration and size distribution of aerosol particles in the size range of 10–1100 nm were monitored, with the focus on the unattached fraction (fun of radon decay products (RnDPs, a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm−3 than in winter (2800 cm−3, and was dominated by 50 nm particles (related to the attached RnDPs in winter. This explains the higher fun values in summer (0.75 and the lower winter measurement (0.04 and, consequently, DCFD values of 43.6 and 13.1 mSv WLM−1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

  2. Radon decay products and 10-1100 nm aerosol particles in Postojna Cave

    Science.gov (United States)

    Bezek, M.; Gregorič, A.; Vaupotič, J.

    2013-03-01

    At the lowest point along the tourist route in Postojna Cave, the activity concentration of radon (222Rn) decay products and the number concentration and size distribution of aerosol particles in the size range of 10-1100 nm were monitored, with the focus on the unattached fraction (fun) of radon decay products (RnDPs), a key parameter in radon dosimetry. The total number concentration of aerosols during visits in summer was lower (700 cm-3) than in winter (2800 cm-3), and was dominated by 50 nm particles (related to the attached RnDPs) in winter. This explains the higher fun values in summer (0.75) and the lower winter measurement (0.04) and, consequently, DCFD values of 43.6 and 13.1 mSv WLM-1 respectively for the calculated dose conversion factors. The difference is caused by an enhanced inflow of fresh outside air, driven in winter by the higher air temperature in the cave compared to outside, resulting in the introduction of outside aerosol particles into the cave.

  3. Understanding the core-halo relation of quantum wave dark matter from 3D simulations.

    Science.gov (United States)

    Schive, Hsi-Yu; Liao, Ming-Hsuan; Woo, Tak-Pong; Wong, Shing-Kwong; Chiueh, Tzihong; Broadhurst, Tom; Hwang, W-Y Pauchy

    2014-12-31

    We examine the nonlinear structure of gravitationally collapsed objects that form in our simulations of wavelike cold dark matter, described by the Schrödinger-Poisson (SP) equation with a particle mass ∼10(-22)  eV. A distinct gravitationally self-bound solitonic core is found at the center of every halo, with a profile quite different from cores modeled in the warm or self-interacting dark matter scenarios. Furthermore, we show that each solitonic core is surrounded by an extended halo composed of large fluctuating dark matter granules which modulate the halo density on a scale comparable to the diameter of the solitonic core. The scaling symmetry of the SP equation and the uncertainty principle tightly relate the core mass to the halo specific energy, which, in the context of cosmological structure formation, leads to a simple scaling between core mass (Mc) and halo mass (Mh), Mc∝a(-1/2)Mh(1/3), where a is the cosmic scale factor. We verify this scaling relation by (i) examining the internal structure of a statistical sample of virialized halos that form in our 3D cosmological simulations and by (ii) merging multiple solitons to create individual virialized objects. Sufficient simulation resolution is achieved by adaptive mesh refinement and graphic processing units acceleration. From this scaling relation, present dwarf satellite galaxies are predicted to have kiloparsec-sized cores and a minimum mass of ∼10(8)M⊙, capable of solving the small-scale controversies in the cold dark matter model. Moreover, galaxies of 2×10(12)M⊙ at z=8 should have massive solitonic cores of ∼2×10(9)M⊙ within ∼60  pc. Such cores can provide a favorable local environment for funneling the gas that leads to the prompt formation of early stellar spheroids and quasars.

  4. Measurement of airborne concentrations of radon-220 daughter products by alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Kerr, G.D.; Ryan, M.T.; Perdue, P.T.

    1978-01-01

    The decay of naturally occurring uranium-238 and thorium-232 produces radon-222 and radon-220 isotopes which can escape into the atmosphere. If these radon gases become concentrated in air, their daughter products may present an inhalation hazard to man. The airborne concentrations of radon-222 can usually be measured very accurately in the presence of normal airborne concentrations of radon-220 and its daughters. In contrast, the measurements of the airborne concentrations of radon-220 daughters are usually complicated by the presence of radon-222 and its daughters even at normally occurring airborne concentrations. The complications involved in these measurements can be overcome in most situations by using an alpha particle spectrometer to distinguish the activity of radon-222 daughters from that due to radon-220 daughters collected on a filter. A practical spectrometer for field measurements of alpha particle activity on a filter is discussed

  5. Pair production of exotic particles at pp(p-barp) colliding beams

    International Nuclear Information System (INIS)

    Borisov, G.V.; Pirogov, Yu.F.; Rudakov, K.R.

    1986-01-01

    A complete set of differential cross sections has been obtained in Born approximation for pair production of exotic particles with various spins J=0, 1/2, 1 and quantum numbers (colored and colorless) both in qq-bar and gg-collisions. The connection of the unitarity of vector boson processes with gauge invariance, factorization properties of non-Abelian gauge amplitudes and the presence of kinematic zeros is used. Besides, the problem of admissibility of massless limit for these processes is being discussed. The yield of exotic particle pairs at pp(p-barp) colliding beams in TeV energy range have been calculated and limits for the accessible mass range have been found

  6. Finite-size effects on two-particle production in continuous and discrete spectrum

    CERN Document Server

    Lednicky, R

    2005-01-01

    The effect of a finite space-time extent of particle production region on the lifetime measurement of hadronic atoms produced by a high energy beam in a thin target is discussed. Particularly, it is found that the neglect of this effect on the pionium lifetime measurement in the experiment DIRAC at CERN could lead to the lifetime overestimation on the level of the expected 10% statistical error. It is argued that the data on correlations of identical particles obtained in the same experimental conditions, together with transport code simulation, allow to diminish the systematic error in the extracted lifetime to an acceptable level. The theoretical systematic errors arising in the calculation of the finite-size effect due to the neglect of non-equal emission times in the pair c.m.s., the space-time coherence and the residual charge are shown to be negligible.

  7. Heterogeneous kinetics, products, and mechanisms of ferulic acid particles in the reaction with NO3 radicals

    Science.gov (United States)

    Liu, Changgeng; Zhang, Peng; Wen, Xiaoying; Wu, Bin

    2017-03-01

    Methoxyphenols, as an important component of wood burning, are produced by lignin pyrolysis and considered to be the potential tracers for wood smoke emissions. In this work, the heterogeneous reaction between ferulic acid particles and NO3 radicals was investigated. Six products including oxalic acid, 4-vinylguaiacol, vanillin, 5-nitrovanillin, 5-nitroferulic acid, and caffeic acid were confirmed by gas chromatography-mass spectrometry (GC-MS). In addition, the reaction mechanisms were proposed and the main pathways were NO3 electrophilic addition to olefin and the meta-position to the hydroxyl group. The uptake coefficient of NO3 radicals on ferulic acid particles was 0.17 ± 0.02 and the effective rate constant under experimental conditions was (1.71 ± 0.08) × 10-12 cm3 molecule-1 s-1. The results indicate that ferulic acid degradation by NO3 can be an important sink at night.

  8. Particle production and Boltzmann integral form of relativistic quantum transport theory

    International Nuclear Information System (INIS)

    Rafelski, J.; Davis, E.D.; Bialynicki-Birula, I.

    1993-01-01

    The 3+3+1 dimensional relativistic quantum transport equation for the fermion matter field, combines the particle pair production with flow phenomena, which occur at very different time scale. A direct numerical treatment of dynamical situations is therefore practically impossible. The authors attempt a seperation of these two sectors by the method of prediagonalization of the integral equations. They exploit the structure of the resolvent of the transport equations: it contains two poles corresponding to the flow sector and two to the pair production sector. Their hope for practical applications is to treat matter flow as a classical phenomenon and to be able to obtain an integral term describing the pair production accurately

  9. Neutral strange particle production in neutrino and antineutrino charged current interactions on protons

    Science.gov (United States)

    Jones, G. T.; Jones, R. W. L.; Kennedy, B. W.; O'Neale, S. W.; Villalobos-Baillie, O.; Klein, H.; Morrison, D. R. O.; Schmid, P.; Wachsmuth, H.; Miller, D. B.; Mobayyen, M. M.; Wainstein, S.; Aderholz, M.; Hantke, D.; Katz, U. F.; Kern, J.; Schmitz, N.; Wittek, W.; Borner, H. P.; Myatt, G.; Radojicic, D.; Bullock, F. W.; Burke, S.

    1993-06-01

    The production of the neutral strange particles K 0, Λ andbar Λ in vp andbar vp charged current interactions is studied in an experiment with the Big European Bubble Chamber. Mean multiplicities are measured as a function of the event variables E v, W 2 and Q 2 and of the hadron variables x F, z and p {T/2}. K *± (892) and ∑ *± (1385) signals are observed, whereas there is no evidence for ∑ *- (1385) production in vp scattering. Forward, backward and total mean multiplicities are found to compare well with the predictions of an empirical model for deep-inelastic reactions in the case of the strange mesons K 0 and K *± (892) but less so for the strange baryons Λ,bar Λ and ∑ *± (1385). The strange baryon multiplicities are used to obtain the decuplet to octet baryon production ratio and to assess the probabilities of a uu or ud system to break up.

  10. Solid sand particle addition can enhance the production of resting cysts in dinoflagellates

    Science.gov (United States)

    Yang, Aoao; Hu, Zhangxi; Tang, Yingzhong

    2018-03-01

    Resting cysts are an important part of the life cycle for many harmful algal bloom-forming dinoflagellates, and play vital roles in the recurrence and geographical spread of harmful algal blooms. Numerous factors have been suggested to regulate the formation of resting cysts, although only a few have been proven to be significant. Cyst formation can be induced by adverse environmental conditions such as drastic changes in temperature, light, salinity, and nutrient levels, and by biological interactions. In this study, we evaluated the ability of an artificial factor (fine sand particles) to enhance the formation of resting cysts. Fine sand particles were added to cultures of dinoflagellates that are known to produce cysts. The addition of fine sand particles significantly increased both the production rate and final yield of cysts in cultures of Scrippsiella trochoidea, Biecheleria brevisulcata, and Levanderina fissa (= Gymnodinium fissum, Gyrodinium instriatum, Gyrodinium uncatenum). The largest increase in the final yield (107-fold) of cysts as a result of sand addition was in S. trochoidea. However, addition of fine sand particles did not induce cyst formation, or barely affected cyst formation, in Akashiwo sanguinea, Cochlodinium polykrikoides and Pheopolykrikos hartmannii, which are also known to be cyst-producing species. We speculated that addition of sand significantly increased the chances of cell collision, which triggered cyst formation. However, further research is required to test this idea. Importantly, our findings indicate that the addition of fine sand particles is a useful method to obtain a large quantity of cysts in a short time for laboratory studies or tests; for example, if a cyst viability test is being used to assess the effectiveness of ships' ballast water treatment.

  11. Binary White Dwarfs in the Galactic Halo

    NARCIS (Netherlands)

    van Oirschot, Pim; Nelemans, Gijs; Helmi, Amina; Starkenburg, Else; Pols, Onno; Brown, Anthony G. A.

    We use the stellar population synthesis code SeBa (Portegies Zwart & Verbunt (1996), Toonen, Nelemans & Portegies Zwart (2012)) to study the halo white dwarf population. Here we assume a Kroupa initial mass function and compare 4 models, varying two parameters: the star formation (SF) history of the

  12. Numerical experiments on galactic halo formation

    International Nuclear Information System (INIS)

    Quinn, P.J.; Salmon, J.K.; Zurek, W.H.

    1986-01-01

    We have used a hybrid N-body-FFT approach to solving Poisson's equation in a cosmological setting. Using this method, we have explored the connection between the form of the initial Gaussian density perturbations that by today have grown into galaxies and the internal properties of the individual galactic halos that are formed. 19 refs., 4 figs

  13. Reflection halo twins : subsun and supersun

    NARCIS (Netherlands)

    Konnen, Gunther P.; van der Werf, Siebren Y.

    2011-01-01

    From an aircraft, a short distinct vertical structure is sometimes seen above the setting sun. Such a feature can be understood as a halo, which is the counterpart of the well-known subsun. Whereas the latter arises from reflections off basal faces of plate-oriented ice crystals illuminated from

  14. Cosmology and cluster halo scaling relations

    NARCIS (Netherlands)

    Araya-Melo, Pablo A.; van de Weygaert, Rien; Jones, Bernard J. T.

    2009-01-01

    We explore the effects of dark matter and dark energy on the dynamical scaling properties of galaxy clusters. We investigate the cluster Faber-Jackson (FJ), Kormendy and Fundamental Plane (FP) relations between the mass, radius and velocity dispersion of cluster-sized haloes in cosmological N-body

  15. Production of particle clustern in 50 GeV/cπ- -N and cosmic ray interactions

    International Nuclear Information System (INIS)

    Kaul, S.K.

    1977-01-01

    The role of particle clusters in multiple-pion production at accelerator and cosmic ray energies is studied employing the high multiplicity (nsub(c) > = 9) accelerator data at 50 GeV/c, and cosmic ray α-N and N-N data at 0.1-1.21 TeV and 0.25-42.3 TeV respectively. The clusters in individual interactions have been identified by employing three methods. In interactions where the measurement of the secondaries was possible, the parameters of the clusters were found from the kinematics of the cluster production process and in it rest of the cases the parameters were determined by the conventional method. A phenomeological investigation of the following aspects has been made: (i) mass and decay particles of the cluster, (ii) transverse momentum of the cluster, (iii) angular distribution of the secondary particles in the cluster system, and (iv) average momentum (Psub(0)) of the pions in the cluster-rest system. In majority of the events of each type of interactions, at least one cluster is emitted. The average characteristics of clusters produced in double and single cluster events have been found to be similar. The average mass of the cluster and the number of its charged decay particles have been found to be 1.79 +- 0.2 GeV and 5.78 +- 0.4 GeV respectively. Value of (Psub(0)) has been found to be (161.2 +- 12) MeV/c. It has been observed that the features of the clusters at accelerator and cosmic ray energies are almost similar. (author)

  16. Molecular and process design for rotavirus-like particle production in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Palomares Laura A

    2011-05-01

    Full Text Available Abstract Background Virus-like particles (VLP have an increasing range of applications including vaccination, drug delivery, diagnostics, gene therapy and nanotechnology. These developments require large quantities of particles that need to be obtained in efficient and economic processes. Production of VLP in yeast is attractive, as it is a low-cost protein producer able to assemble viral structural proteins into VLP. However, to date only single-layered VLP with simple architecture have been produced in this system. In this work, the first steps required for the production of rotavirus-like particles (RLP in S. cerevisiae were implemented and improved, in order to obtain the recombinant protein concentrations required for VLP assembly. Results The genes of the rotavirus structural proteins VP2, VP6 and VP7 were cloned in four Saccharomyces cerevisiae strains using different plasmid and promoter combinations to express one or three proteins in the same cell. Performance of the best constructs was evaluated in batch and fed-batch cultures using a complete synthetic media supplemented with leucine, glutamate and succinate. The strain used had an important effect on recombinant protein concentration, while the type of plasmid, centromeric (YCp or episomal (YEp, did not affect protein yields. Fed-batch culture of the PD.U-267 strain resulted in the highest concentration of rotavirus proteins. Volumetric and specific productivities increased 28.5- and 11-fold, respectively, in comparison with batch cultures. Expression of the three rotavirus proteins was confirmed by immunoblotting and RLP were detected using transmission electron microscopy. Conclusions We present for the first time the use of yeast as a platform to express multilayered rotavirus-like particles. The present study shows that the combined use of molecular and bioprocess tools allowed the production of triple-layered rotavirus RLP. Production of VLP with complex architecture in yeasts

  17. Hazardous gas production by alpha particles in solid organic transuranic waste matrices. 1998 annual progress report

    International Nuclear Information System (INIS)

    LaVerne, J.A.

    1998-01-01

    'This project uses fundamental radiation chemical techniques to elucidate the basic processes occurring in the heavy-ion radiolysis of solid hydrocarbon matrices such as polymers and organic resins that are associated with many of the transuranic waste deposits or the transportation of these radionuclides. The environmental management of mixed waste containing transuranic radionuclides is difficult because these nuclides are alpha particle emitters and the energy deposited by the alpha particles causes chemical transformations in the matrices accompanying the waste. Most radiolysis programs focus on conventional radiation such as gamma rays, but the chemical changes induced by alpha particles and other heavy ions are typically very different and product yields can vary by more than an order of magnitude. The objective of this research is to measure the production of gases, especially molecular hydrogen, produced in the proton, helium ion, and carbon ion radiolysis of selected solid organic matrices in order to obtain fundamental mechanistic information on the radiolytic decomposition of these materials. This knowledge can also be used to directly give reasonable estimates of explosive or flammability hazards in the storage or transport of transuranic wastes in order to enhance the safety of DOE sites. This report summarizes the work after eight months of a three-year project on determining the production of hazardous gases in transuranic waste. The first stage of the project was to design and build an assembly to irradiate solid organic matrices using accelerated ion beams. It is necessary to measure absolute radiolytic yields, and simulate some of the conditions found in the field. A window assembly was constructed allowing the beam to pass consecutively through a collimator, a vacuum exit window and into the solid sample. The beam is stopped in the sample and the entire end of the assembly is a Faraday cup. Integration of the collected current, in conjunction

  18. Neutral strange particle production at top SPS energy measured by the CERES experiment

    International Nuclear Information System (INIS)

    Radomski, S.

    2006-01-01

    Systematics of strange particle production in collisions of ultrarelativistic nuclei provides an insight into the properties of the strongly interacting matter. Hadrochemistry, the study of the relative yields, provides information about chemical freeze-out and the position of the system in the phase diagram. Strangeness production at Super Proton Synchrotron (SPS) energies is not fully explained by the thermal model of hadron gas. Data reported by one experiment show sharp structures as a function of energy which are interpreted as a signature for a phase transition, but due to discrepancies in the results between two different experiments, a conclusion can not be drawn. This thesis is part of an effort to build a database of the strangeness production at SPS energy. The particular subject of this work is a precise measurement of the production of K S 0 . The results are compared with two other experiments and the prediction of the thermal model. The high precision data shed light on the systematics of strangeness production and allow clarification of the experimental status. The study of transverse momentum spectra provides information about the temperature and the radial expansion of the system. Here, as in the case of particle yields, interesting structures are visible as a function of energy. A rapid increase in the number of degrees of freedom is visible in the SPS region. A large part of the strangeness is carried by the neutral strange baryon Λ. Here the experimental situation is even more complicated because the reconstruction of the Λ yield requires large extrapolation to low transverse momentum. In this work first results on Λ production will be presented. (orig.)

  19. Neutral strange particle production at top SPS energy measured by the CERES experiment

    Energy Technology Data Exchange (ETDEWEB)

    Radomski, S.

    2006-07-05

    Systematics of strange particle production in collisions of ultrarelativistic nuclei provides an insight into the properties of the strongly interacting matter. Hadrochemistry, the study of the relative yields, provides information about chemical freeze-out and the position of the system in the phase diagram. Strangeness production at Super Proton Synchrotron (SPS) energies is not fully explained by the thermal model of hadron gas. Data reported by one experiment show sharp structures as a function of energy which are interpreted as a signature for a phase transition, but due to discrepancies in the results between two different experiments, a conclusion can not be drawn. This thesis is part of an effort to build a database of the strangeness production at SPS energy. The particular subject of this work is a precise measurement of the production of K{sub S}{sup 0}. The results are compared with two other experiments and the prediction of the thermal model. The high precision data shed light on the systematics of strangeness production and allow clarification of the experimental status. The study of transverse momentum spectra provides information about the temperature and the radial expansion of the system. Here, as in the case of particle yields, interesting structures are visible as a function of energy. A rapid increase in the number of degrees of freedom is visible in the SPS region. A large part of the strangeness is carried by the neutral strange baryon {lambda}. Here the experimental situation is even more complicated because the reconstruction of the {lambda} yield requires large extrapolation to low transverse momentum. In this work first results on {lambda} production will be presented. (orig.)

  20. Applications of SCET to the pair production of supersymmetric particles at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Broggio, Alessandro

    2013-02-04

    In this thesis we investigate the phenomenology of supersymmetric particles at hadron colliders beyond next-to-leading order (NLO) in perturbation theory. We discuss the foundations of Soft-Collinear Effective Theory (SCET) and, in particular, we explicitly construct the SCET Lagrangian for QCD. As an example, we discuss factorization and resummation for the Drell-Yan process in SCET. We use techniques from SCET to improve existing calculations of the production cross sections for slepton-pair production and top-squark-pair production at hadron colliders. As a first application, we implement soft-gluon resummation at next-to-next-to-next-to-leading logarithmic order (NNNLL) for slepton-pair production in the minimal supersymmetric extension of the Standard Model (MSSM). This approach resums large logarithmic corrections arising from the dynamical enhancement of the partonic threshold region caused by steeply falling parton luminosities. We evaluate the resummed invariant-mass distribution and total cross section for slepton-pair production at the Tevatron and LHC and we match these results, in the threshold region, onto NLO fixed-order calculations. As a second application we present the most precise predictions available for top-squark-pair production total cross sections at the LHC. These results are based on approximate NNLO formulas in fixed-order perturbation theory, which completely determine the coefficients multiplying the singular plus distributions. The analysis of the threshold region is carried out in pair invariant mass (PIM) kinematics and in single-particle inclusive (1PI) kinematics. We then match our results in the threshold region onto the exact fixed-order NLO results and perform a detailed numerical analysis of the total cross section.

  1. Double gate graphene nanoribbon field effect transistor with single halo pocket in channel region

    Science.gov (United States)

    Naderi, Ali

    2016-01-01

    A new structure for graphene nanoribbon field-effect transistors (GNRFETs) is proposed and investigated using quantum simulation with a nonequilibrium Green's function (NEGF) method. Tunneling leakage current and ambipolar conduction are known effects for MOSFET-like GNRFETs. To minimize these issues a novel structure with a simple change of the GNRFETs by using single halo pocket in the intrinsic channel region, "Single Halo GNRFET (SH-GNRFET)", is proposed. An appropriate halo pocket at source side of channel is used to modify potential distribution of the gate region and weaken band to band tunneling (BTBT). In devices with materials like Si in channel region, doping type of halo and source/drain regions are different. But, here, due to the smaller bandgap of graphene, the mentioned doping types should be the same to reduce BTBT. Simulations have shown that in comparison with conventional GNRFET (C-GNRFET), an SH-GNRFET with appropriately halo doping results in a larger ON current (Ion), smaller OFF current (Ioff), a larger ON-OFF current ratio (Ion/Ioff), superior ambipolar characteristics, a reduced power-delay product and lower delay time.

  2. Baryonic pinching of galactic dark matter halos

    International Nuclear Information System (INIS)

    Gustafsson, Michael; Fairbairn, Malcolm; Sommer-Larsen, Jesper

    2006-01-01

    High resolution cosmological N-body simulations of four galaxy-scale dark matter halos are compared to corresponding N-body/hydrodynamical simulations containing dark matter, stars and gas. The simulations without baryons share features with others described in the literature in that the dark matter density slope continuously decreases towards the center, with a density ρ DM ∝r -1.3±0.2 , at about 1% of the virial radius for our Milky Way sized galaxies. The central cusps in the simulations which also contain baryons steepen significantly, to ρ DM ∝r -1.9±0.2 , with an indication of the inner logarithmic slope converging. Models of adiabatic contraction of dark matter halos due to the central buildup of stellar/gaseous galaxies are examined. The simplest and most commonly used model, by Blumenthal et al., is shown to overestimate the central dark matter density considerably. A modified model proposed by Gnedin et al. is tested and it is shown that, while it is a considerable improvement, it is not perfect. Moreover, it is found that the contraction parameters in their model not only depend on the orbital structure of the dark-matter-only halos but also on the stellar feedback prescription which is most relevant for the baryonic distribution. Implications for dark matter annihilation at the galactic center are discussed and it is found that, although our simulations show a considerable reduced dark matter halo contraction as compared to the Blumenthal et al. model, the fluxes from dark matter annihilation are still expected to be enhanced by at least a factor of a hundred, as compared to dark-matter-only halos. Finally, it is shown that, while dark-matter-only halos are typically prolate, the dark matter halos containing baryons are mildly oblate with minor-to-major axis ratios of c/a=0.73±0.11, with their flattening aligned with the central baryonic disks

  3. THE HALO OCCUPATION DISTRIBUTION OF SDSS QUASARS

    International Nuclear Information System (INIS)

    Richardson, Jonathan; Chatterjee, Suchetana; Nagai, Daisuke; Zheng Zheng; Shen Yue

    2012-01-01

    We present an estimate of the projected two-point correlation function (2PCF) of quasars in the Sloan Digital Sky Survey (SDSS) over the full range of one- and two-halo scales, 0.02 h –1 Mpc p –1 Mpc. This was achieved by combining data from SDSS DR7 on large scales and Hennawi et al. (with appropriate statistical corrections) on small scales. Our combined clustering sample is the largest spectroscopic quasar clustering sample to date, containing ∼48, 000 quasars in the redshift range 0.4 ∼ sat = (7.4 ± 1.4) × 10 –4 , be satellites in dark matter halos. At z ∼ 1.4, the median masses of the host halos of central and satellite quasars are constrained to be M cen = 4.1 +0.3 –0.4 × 10 12 h –1 M ☉ and M sat = 3.6 +0.8 –1.0 × 10 14 h –1 M ☉ , respectively. To investigate the redshift evolution of the quasar-halo relationship, we also perform HOD modeling of the projected 2PCF measured by Shen et al. for SDSS quasars with median redshift 3.2. We find tentative evidence for an increase in the mass scale of quasar host halos—the inferred median mass of halos hosting central quasars at z ∼ 3.2 is M cen = 14.1 +5.8 –6.9 × 10 12 h –1 M ☉ . The cutoff profiles of the mean occupation functions of central quasars reveal that quasar luminosity is more tightly correlated with halo mass at higher redshifts. The average quasar duty cycle around the median host halo mass is inferred to be f q = 7.3 +0.6 –1.5 × 10 –4 at z ∼ 1.4 and f q = 8.6 +20.4 –7.2 × 10 –2 at z ∼ 3.2. We discuss the implications of our results for quasar evolution and quasar-galaxy co-evolution.

  4. Insight into particle production mechanisms via angular correlations of identified particles in pp collisions at √(s) = 7 TeV

    International Nuclear Information System (INIS)

    Adam, J.; Adamova, D.; Aggarwal, M.M.

    2017-01-01

    Two-particle angular correlations were measured in pp collisions at √(s) = 7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon-baryon and anti-baryon-anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an open question. (orig.)

  5. Insight into particle production mechanisms via angular correlations of identified particles in pp collisions at √(s) = 7 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Adam, J. [Czech Technical Univ., Prague (Czech Republic). Faculty of Nuclear Sciences and Physical Engineering; Adamova, D. [Academy of Sciences of the Czech Republic, Rez u Prahy (Czech Republic). Nuclear Physics Inst.; Aggarwal, M.M. [Panjab Univ., Chandigarh (India). Physics Dept.; Collaboration: ALICE Collaboration; and others

    2017-08-15

    Two-particle angular correlations were measured in pp collisions at √(s) = 7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon-baryon and anti-baryon-anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an open question. (orig.)

  6. Effect of raw soya bean particle size on productive performance and digestion of dairy cows.

    Science.gov (United States)

    Naves, A B; Freitas Júnior, J E; Barletta, R V; Gandra, J R; Calomeni, G D; Gardinal, R; Takiya, C S; Vendramini, T H A; Mingoti, R D; Rennó, F P

    2016-08-01

    Differing soya bean particle sizes may affect productive performance and ruminal fermentation due to the level of fatty acid (FA) exposure of the cotyledon in soya bean grain and because the protein in small particles is more rapidly degraded than the protein in large particles, which influence ruminal fibre digestion and the amounts of ruminally undegradable nutrients. The objective of this experiment was to investigate the effects of raw soya bean particle size on productive performance, digestion and milk FA profile of dairy cows. Twelve Holstein cows were assigned to three 4 × 4 Latin squares with 21-day periods. At the start of the experiment, cows were 121 days in milk (DIM) and yielded 30.2 kg/day of milk. Cows were fed 4 diets: (i) control diet (CO), without raw soya bean; (ii) whole raw soya bean (WRS); (iii) cracked raw soya bean in Wiley mill 4-mm screen (CS4); and (iv) cracked raw soya bean in Wiley mill 2-mm screen (CS2). The inclusion of soya beans (whole or cracked) was 200 g/kg on dry matter (DM) basis and partially replaced ground corn and soya bean meal. Uncorrected milk yield and composition were not influenced by experimental diets; however, fat-corrected milk (FCM) decreased when cows were fed soya bean treatments. Soya bean diets increased the intake of ether extract (EE) and net energy of lactation (NEL ), and decreased the intake of DM and non-fibre carbohydrate (NFC). Ruminal propionate concentration was lower in cows fed WRS than cows fed CS2 or CS4. Cows fed cracked raw soya bean presented lower nitrogen in faeces than cows fed WRS. The milk of cows fed WRS, CS2 and CS4 presented higher unsaturated FA than cows fed CO. The addition of raw soya bean in cow diets, regardless of the particle size, did not impair uncorrected milk yield and nutrient digestion, and increased the concentration of unsaturated FA in milk. Cows fed cracked raw soya bean presented similar productive performance to cows fed whole raw soya bean. Journal of

  7. Data Products From Particle Detectors On-Board NOAA's Newest Space Weather Monitor

    Science.gov (United States)

    Kress, B. T.; Rodriguez, J. V.; Onsager, T. G.

    2017-12-01

    NOAA's newest Geostationary Operational Environmental Satellite, GOES-16, was launched on 19 November 2016. Instrumentation on-board GOES-16 includes the new Space Environment In-Situ Suite (SEISS), which has been collecting data since 8 January 2017. SEISS is composed of five magnetospheric particle sensor units: an electrostatic analyzer for measuring 30 eV - 30 keV ions and electrons (MPS-LO), a high energy particle sensor (MPS-HI) that measures keV to MeV electrons and protons, east and west facing Solar and Galactic Proton Sensor (SGPS) units with 13 differential channels between 1-500 MeV, and an Energetic Heavy Ion Sensor (EHIS) that measures 30 species of heavy ions (He-Ni) in five energy bands in the 10-200 MeV/nuc range. Measurement of low energy magnetospheric particles by MPS-LO and heavy ions by EHIS are new capabilities not previously flown on the GOES system. Real-time data from GOES-16 will support space weather monitoring and first-principles space weather modeling by NOAA's Space Weather Prediction Center (SWPC). Space weather level 2+ data products under development at NOAA's National Centers for Environmental Information (NCEI) include the Solar Energetic Particle (SEP) Event Detection algorithm. Legacy components of the SEP event detection algorithm (currently produced by SWPC) include the Solar Radiation Storm Scales. New components will include, e.g., event fluences. New level 2+ data products also include the SEP event Linear Energy Transfer (LET) Algorithm, for transforming energy spectra from EHIS into LET spectra, and the Density and Temperature Moments and Spacecraft Charging algorithm. The moments and charging algorithm identifies electron and ion signatures of spacecraft surface (frame) charging in the MPS-LO fluxes. Densities and temperatures from MPS-LO will also be used to support a magnetopause crossing detection algorithm. The new data products will provide real-time indicators of potential radiation hazards for the satellite

  8. Fission product retention in TRISO coated UO2 particle fuels subjected to HTR simulated core heating tests

    International Nuclear Information System (INIS)

    Baldwin, C.A.; Kania, M.J.

    1991-01-01

    Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbounded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 deg. C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 deg. C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 deg. C and above may exist. (author). 6 refs, 6 figs, 4 tabs

  9. Fission product retention in TRISCO coated UO2 particle fuels subjected to HTR simulated core heating tests

    International Nuclear Information System (INIS)

    Baldwin, C.A.; Kania, M.J.

    1990-11-01

    Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbonded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 degree C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 degree C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 degree C and above may exist. 6 refs., 6 figs., 4 tabs

  10. Liquid-borne nano particles impact on the random yield during critical processes in IC’s production

    NARCIS (Netherlands)

    Wali, F.; Knotter, D. Martin; Kuper, F.G.

    2008-01-01

    Semiconductor industry faces a continuous challenge to decrease the transistor size as well as to increase the yield by eliminating defect sources. One of the sources of particle defects is ultra pure water used in different production tools at different stages of processing. In this paper, particle

  11. Hyperon and negative particle production at central rapidity in proton-beryllium interactions at 158 GeV/c

    Czech Academy of Sciences Publication Activity Database

    Antinori, F.; Bakke, H.; Beusch, W.; Staroba, Pavel; Závada, Petr

    1999-01-01

    Roč. 661, - (1999), 476c-480c ISSN 0375-9474 Institutional research plan: CEZ:AV0Z1010920 Keywords : CERN SPS * WA97 * proton-beryllium collisions * hyperon * negaive particle production Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 2.088, year: 1999

  12. Investigations of the neutron halo by radioactive beam experiments

    International Nuclear Information System (INIS)

    Mueller, A.C.

    1993-01-01

    Recently, a new tool has become available to study the behaviour of nuclei at the limits of particle stability. Heavy-ion projectile fragmentation, in combination with efficient recoil spectrometers, allows to prepare 'exotic' beams which can be used to induce secondary nuclear reactions. First experiments have revealed surprising features in the reactions of the most neutron-rich light nuclei. There is now conclusive evidence that the observed effects are due to long-tail matter distributions ('neutron halo') which occur for the last, very weakly bound neutrons. The results of some recent radioactive beam experiments, made by means of the spectrometer LISE3 at GANIL, are presented. (author) 24 refs.; 7 figs

  13. Robust production of virus-like particles and monoclonal antibodies with geminiviral replicon vectors in lettuce

    Science.gov (United States)

    Lai, Huafang; He, Junyun; Engle, Michael; Diamond, Michael S.; Chen, Qiang

    2011-01-01

    Summary Pharmaceutical protein production in plants has been greatly promoted by the development of viral-based vectors and transient expression systems. Tobacco and related Nicotiana species are currently the most common host plants for generation of plant-made pharmaceutical proteins (PMPs). Downstream processing of target PMPs from these plants, however, is hindered by potential technical and regulatory difficulties due to the presence of high levels of phenolics and toxic alkaloids. Here, we explored the use of lettuce, which grows quickly yet produces low levels of secondary metabolites, and viral vector-based transient expression systems to develop a robust PMP production platform. Our results showed that a geminiviral replicon system based on the bean yellow dwarf virus permits high-level expression in lettuce of virus-like particles (VLP) derived from the Norwalk virus capsid protein and therapeutic monoclonal antibodies (mAbs) against Ebola and West Nile viruses. These vaccine and therapeutic candidates can be readily purified from lettuce leaves with scalable processing methods while fully retaining functional activity. Furthermore, this study also demonstrated the feasibility of using commercially produced lettuce for high-level PMP production. This allows our production system to have access to unlimited quantities of inexpensive plant material for large-scale production. These results establish a new production platform for biological pharmaceutical agents that is effective, safe, low-cost, and amenable to large-scale manufacturing. PMID:21883868

  14. Production and characterization of monodisperse uranium particles for nuclear safeguards applications

    Energy Technology Data Exchange (ETDEWEB)

    Knott, Alexander

    2016-07-01

    Environmental sampling is a very effective measure to detect undeclared nuclear activities. Generally, samples are taken as swipe samples on cotton. These swipes contain minute quantities of particulates which have an inherent signature of their production and release scenario. These inspection samples are assessed for their morphology, elemental composition and their isotopic vectors. Mass spectrometry plays a crucial role in determining the isotopic ratios of uranium. Method validation and instrument calibration with well-characterized quality control (QC)-materials, reference materials (RMs) and certified reference materials (CRMs) ensures reliable data output. Currently, the availability of suitable well defined microparticles containing uranium and plutonium reference materials is very limited. Primarily, metals, oxides and various uranium and plutonium containing solutions are commercially available. Therefore, the IAEA's Safeguards Analytical Services (SGAS) cooperates with the Institute of Nuclear Waste Management and Reactor Safety (IEK-6) at the Forschungszentrum Juelich GmbH in a joint task entitled ''Production of Particle Reference Materials''. The work presented in this thesis has been partially funded by the IAEA, Forschungszentrum Juelich GmbH and the Federal Ministry of Economic Affairs and Energy (BMWi) through the ''Joint Program on the Technical Development and Further Improvement of IAEA Safeguards between the Government of the Federal Republic of Germany and the IAEA''. The first step towards monodisperse microparticles was the development of pure uranium oxide particles made from certified reference materials. The focus of the dissertation is (1) the implementation of a working setup to produce monodisperse uranium oxide particles and (2) the characterization of these particles towards the application as QC-material. Monodisperse uranium oxide particles were produced by spray pyrolysis. It was

  15. Analytic mappings: a new approach in particle production by accelerated observers

    International Nuclear Information System (INIS)

    Sanchez, N.

    1982-01-01

    This is a summary of the authors recent results about physical consequences of analytic mappings in the space-time. Classically, the mapping defines an accelerated frame. At the quantum level it gives rise to particle production. Statistically, the real singularities of the mapping have associated temperatures. This concerns a new approach in Q.F.T. as formulated in accelerated frames. It has been considered as a first step in the understanding of the deep connection that could exist between the structure (geometry and topology) of the space-time and thermodynamics, mainly motivated by the works of Hawking since 1975. (Auth.)

  16. Neutral strange particle production in π-p interactions at 16 GeV/c

    International Nuclear Information System (INIS)

    Balea, E.; Berceanu, S.; Coca, C.; Sararu, A.; Karnaukhov, M.V.; Moroz, I.V.; Kellner, G.; Mihul, A.

    1979-06-01

    The production of Ksub(s)sup(0), Λ and anti Λ in π - p interactions at 16 GeV/c is investigated. Cross sections for single strange particle are determined, both inclusively and as functions of the charged multiplicity. Some characteristics of the multiplicity distributions are also discussed. Inclusive distributions are studied as function of longitudinal and transverse variables of Vsup(0) and missing mass squared. The average charged multiplicities of the systems recoiling against the Λ and Ksub(s)sup(0) are presented. (author)

  17. Negative particle production in the fragmentation region at the CERN ISR

    CERN Document Server

    Albrow, M G; Barber, D P; Bogaerts, A; Bosnjakovic, B; Brooks, J R; Clegg, A B; Erné, F C; Gee, C N P; Locke, D H; Loebinger, F K; Murphy, P G; Rudge, A; Sens, Johannes C; Van der Veen, F

    1973-01-01

    Data are reported on the production of pi /sup -/, K/sup -/ and p in proton-proton collisions at the CERN ISR. Measurements have been made at fixed c.m. angles in the range (x, p/sub T/)=(0.12, 0.16 GeV/c) to (x, p/sub T/)=(0.82, 1.1 GeV/c), over a range of squared c.m. energy 558particles. The approach to scaling is discussed. (7 refs).

  18. Studying generalised dark matter interactions with extended halo-independent methods

    Energy Technology Data Exchange (ETDEWEB)

    Kahlhoefer, Felix [DESY, Notkestraße 85,D-22607 Hamburg (Germany); Wild, Sebastian [Physik-Department T30d, Technische Universität München,James-Franck-Straße 1, D-85748 Garching (Germany)

    2016-10-20

    The interpretation of dark matter direct detection experiments is complicated by the fact that neither the astrophysical distribution of dark matter nor the properties of its particle physics interactions with nuclei are known in detail. To address both of these issues in a very general way we develop a new framework that combines the full formalism of non-relativistic effective interactions with state-of-the-art halo-independent methods. This approach makes it possible to analyse direct detection experiments for arbitrary dark matter interactions and quantify the goodness-of-fit independent of astrophysical uncertainties. We employ this method in order to demonstrate that the degeneracy between astrophysical uncertainties and particle physics unknowns is not complete. Certain models can be distinguished in a halo-independent way using a single ton-scale experiment based on liquid xenon, while other models are indistinguishable with a single experiment but can be separated using combined information from several target elements.

  19. Studying generalised dark matter interactions with extended halo-independent methods

    International Nuclear Information System (INIS)

    Kahlhoefer, Felix; Wild, Sebastian

    2016-07-01

    The interpretation of dark matter direct detection experiments is complicated by the fact that neither the astrophysical distribution of dark matter nor the properties of its particle physics interactions with nuclei are known in detail. To address both of these issues in a very general way we develop a new framework that combines the full formalism of non-relativistic effective interactions with state-of-the-art halo-independent methods. This approach makes it possible to analyse direct detection experiments for arbitrary dark matter interactions and quantify the goodness-of-fit independent of astrophysical uncertainties. We employ this method in order to demonstrate that the degeneracy between astrophysical uncertainties and particle physics unknowns is not complete. Certain models can be distinguished in a halo-independent way using a single ton-scale experiment based on liquid xenon, while other models are indistinguishable with a single experiment but can be separated using combined information from several target elements.

  20. Effective description of dark matter self-interactions in small dark matter haloes

    International Nuclear Information System (INIS)

    Kummer, Janis

    2017-07-01

    Self-interacting dark matter may have striking astrophysical signatures, such as observ- able offsets between galaxies and dark matter in merging galaxy clusters. Numerical N-body simulations used to predict such observables typically treat the galaxies as collisionless test particles, a questionable assumption given that each galaxy is embedded in its own dark matter halo. To enable a more accurate treatment we develop an effective description of small dark matter haloes taking into account the two major effects due to dark matter self-scatterings: deceleration and evaporation. We point out that self-scatterings can have a sizeable impact on the trajectories of galaxies, diminishing the separation between galaxies and dark matter in merging clusters. This effect depends sensitively on the underlying particle physics, in particular the angular dependence of the self-scattering cross section, and cannot be predicted from the momentum transfer cross section alone.

  1. Variable production of transparent exopolymeric particles by haploid and diploid life stages of coccolithophores grown under different CO2 concentrations

    NARCIS (Netherlands)

    Pedrotti, M.L.; Fiorini, S.; Kerros, M.E.; Middelburg, J.J.; Gattuso, J.P.

    2012-01-01

    The production of transparent exopolymeric particles (TEP) by the coccolithophores, Emiliania huxleyi, Calcidiscus leptoporus and Syracosphaera pulchra was investigated in batch cultures. The abundance, size spectra and carbon content of TEP were examined during the exponential growth phase of both

  2. CARBON-ENHANCED METAL-POOR STARS IN THE INNER AND OUTER HALO COMPONENTS OF THE MILKY WAY

    International Nuclear Information System (INIS)

    Carollo, Daniela; Norris, John E.; Freeman, Ken C.; Beers, Timothy C.; Lee, Young Sun; Kennedy, Catherine R.; Bovy, Jo; Sivarani, Thirupathi; Aoki, Wako

    2012-01-01

    Carbon-enhanced metal-poor (CEMP) stars in the halo components of the Milky Way are explored, based on accurate determinations of the carbon-to-iron ([C/Fe]) abundance ratios and kinematic quantities for over 30,000 calibration stars from the Sloan Digital Sky Survey. Using our present criterion that low-metallicity stars exhibiting [C/Fe] ratios ( c arbonicity ) in excess of [C/Fe] =+0.7 are considered CEMP stars, the global frequency of CEMP stars in the halo system for [Fe/H] 5 kpc, the CarDF exhibits a strong tail toward high values, up to [C/Fe] > +3.0. We also find a clear increase in the CEMP frequency with |Z|. For stars with –2.0 < [Fe/H] <–1.5, the frequency grows from 5% at |Z| ∼2 kpc to 10% at |Z| ∼10 kpc. For stars with [Fe/H] <–2.0, the frequency grows from 8% at |Z| ∼2 kpc to 25% at |Z| ∼10 kpc. For stars with –2.0 < [Fe/H] <–1.5, the mean carbonicity is ([C/Fe]) ∼+1.0 for 0 kpc < |Z| < 10 kpc, with little dependence on |Z|; for [Fe/H] <–2.0, ([C/Fe]) ∼+1.5, again roughly independent of |Z|. Based on a statistical separation of the halo components in velocity space, we find evidence for a significant contrast in the frequency of CEMP stars between the inner- and outer-halo components—the outer halo possesses roughly twice the fraction of CEMP stars as the inner halo. The carbonicity distribution also differs between the inner-halo and outer-halo components—the inner halo has a greater portion of stars with modest carbon enhancement ([C/Fe] ∼+0.5]); the outer halo has a greater portion of stars with large enhancements ([C/Fe] ∼+2.0), although considerable overlap still exists. We interpret these results as due to the possible presence of additional astrophysical sources of carbon production associated with outer-halo stars, beyond the asymptotic giant-branch source that may dominate for inner-halo stars, with implications for the progenitors of these populations.

  3. Large revealing similarity in multihadron production in nuclear and particle collisions

    International Nuclear Information System (INIS)

    Mishra, Aditya Nath; Sahoo, Raghunath; Sarkisyan, Edward K.G.; Sakharov, Alexander S.; )

    2016-01-01

    The dependencies of charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity as well as of charged particle total multiplicity on the collision energy and on the number of nucleon participants, or centrality, measured in nucleus-nucleus collisions are studied in the energy range spanning a few GeV to a few TeV per nucleon. The model in which the multiparticle production is driven by the dissipating effective energy of participants is considered. The model extends the earlier proposed approach, combining the constituent quark picture together with Landau relativistic hydrodynamics shown to interrelate the measurements from different types of collisions. Within this model, the dependence of the charged particle pseudorapidity density and transverse energy pseudorapidity density at midrapidity on the number of participants in heavy-ion collisions are found to be well described in terms of the effective energy defined as a centrality-dependent fraction of the collision energy. For both variables the effective energy approach reveals a similarity in the energy dependence obtained for the most central collisions and centrality data in the entire available energy range

  4. Strange Particle Production in $p+p$ Collisions at $\\sqrt{s}$= 200GeV

    Energy Technology Data Exchange (ETDEWEB)

    Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett,J.; Anderson, B.D.; Anderson, M.; Arkhipkin, D.; Averichev, G.S.; Bai,Y.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Bhardwaj, S.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L.C.; Blyth, S.-L.; Bonner, B.E.; Botje, M.; Bouchet, J.; Brandin, A.V.; Bravar, A.; Bystersky, M.; Cadman, R.V.; Cai,X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Castillo, J.; Catu,O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen,H.F.; Chen, J.H.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cosentino, M.R.; Cramer, J.G.; Crawford,H.J.; Das, D.; Das, S.; Daugherity, M.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Djawotho,P.; Dogra, S.M.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dunin, V.B.; Dunlop, J.C.; Dutta Mazumdar, M.R.; Eckardt, V.; Edwards, W.R.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch,E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Ganti,M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.S.; Gorbunov, Y.G.; Gos,H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guimaraes, K.S.F.F.; Guo,Y.; Gupta,N.; Gutierrez, T.D.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Henry, T.W.; Hepplemann, S.; Hippolyte,B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Horner, M.J.; Huang, H.Z.; Huang, S.L.; Hughes, E.W.; Humanic, T.J.; Igo, G.; Jacobs,P.; Jacobs, W.W.; Jakl, P.; Jia, F.; Jiang, H.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev, V.Yu.; Kim, B.C.; Kiryluk, J.; Kisiel, A.; Kislov, E.M.; Klein,S.R.; Kocoloski, A.; Koetke, D.D.; et al.

    2006-07-31

    We present strange particle spectra and yields measured atmid-rapidity in sqrt text s=200 GeV proton-proton (p+p) collisions atRHIC. We find that the previously observed universal transverse mass(mathrm mT \\equiv\\sqrt mathrm p_T 2+\\mathrm m2) scaling of hadronproduction in p+p collisions seems to break down at higher \\mt and thatthere is a difference in the shape of the \\mt spectrum between baryonsand mesons. We observe mid-rapidity anti-baryon to baryon ratios nearunity for Lambda and Xi baryons and no dependence of the ratio ontransverse momentum, indicating that our data do not yet reach thequark-jet dominated region. We show the dependence of the mean transversemomentum (\\mpt) on measured charged particle multiplicity and on particlemass and infer that these trends are consistent with gluon-jet dominatedparticle production. The data are compared to previous measurements fromCERN-SPS, ISR and FNAL experiments and to Leading Order (LO) and Next toLeading order (NLO) string fragmentation model predictions. We infer fromthese comparisons that the spectral shapes and particle yields from $p+p$collisions at RHIC energies have large contributions from gluon jetsrather than quark jets.

  5. An new MHD/kinetic model for exploring energetic particle production in macro-scale systems

    Science.gov (United States)

    Drake, J. F.; Swisdak, M.; Dahlin, J. T.

    2017-12-01

    A novel MHD/kinetic model is being developed to explore magneticreconnection and particle energization in macro-scale systems such asthe solar corona and the outer heliosphere. The model blends the MHDdescription with a macro-particle description. The rationale for thismodel is based on the recent discovery that energetic particleproduction during magnetic reconnection is controlled by Fermireflection and Betatron acceleration and not parallel electricfields. Since the former mechanisms are not dependent on kineticscales such as the Debye length and the electron and ion inertialscales, a model that sheds these scales is sufficient for describingparticle acceleration in macro-systems. Our MHD/kinetic model includesmacroparticles laid out on an MHD grid that are evolved with the MHDfields. Crucially, the feedback of the energetic component on the MHDfluid is included in the dynamics. Thus, energy of the total system,the MHD fluid plus the energetic component, is conserved. The systemhas no kinetic scales and therefore can be implemented to modelenergetic particle production in macro-systems with none of theconstraints associated with a PIC model. Tests of the new model insimple geometries will be presented and potential applications will bediscussed.

  6. Search for electroweak production of supersymmetric particles with photonic final states at CMS

    Energy Technology Data Exchange (ETDEWEB)

    Feld, Lutz; Lange, Johannes; Schulz, Johannes [1. Physikalisches Institut B, RWTH Aachen University (Germany)

    2016-07-01

    Supersymmetry (SUSY) is a prominent extension of the standard model of particle physics, providing possible solutions to the hierarchy problem, unification of the coupling constants and the existence of dark matter. In the context of gauge mediated SUSY breaking the next-to-lightest SUSY particle (NLSP) is the lightest neutralino, while the gravitino is the lightest SUSY particle. For a bino-like mixture, the NLSP predominantly decays to a photon and a gravitino, the latter leaving the detector undetected. This analysis focuses on final states containing at least one photon, missing transverse energy and low hadronic activity, thus increasing the sensitivity to electroweak gaugino production and complementing searches requiring the presence of jets. The main background contributions are estimated using a template fit of the background simulations to the data in a control region. The search has already been carried out using a special parked data set recorded by the CMS detector at √(s)=8 TeV and an integrated luminosity of 7.4 fb{sup -1}. We present the current status of the analysis for the LHC RunII at √(s)=13 TeV.

  7. Study of Particle Production and Nuclear Fragmentation in Relativistic Heavy-Ion Collisions in Nuclear Emulsions

    CERN Multimedia

    2002-01-01

    % EMU11 \\\\ \\\\ We propose to use nuclear emulsions for the study of nuclear collisions of $^{207}$Pb, $^{197}$Au, and any other heavy-ion beams when they are available. We have, in the past, used $^{32}$S at 200A~GeV and $^{16}$O at 200A and 60A~GeV from CERN (Experiment EMU08) and at present the analysis is going on with $^{28}$Si beam from BNL at 14.5A~GeV. It will be important to compare the previous and the present investigations with the new $^{207}$Pb beam at 60-160A~GeV. We want to measure in nuclear emulsion, on an event by event basis, shower particle multiplicity, pseudorapidity density and density fluctuations of charged particles, charge multiplicity and angular distributions of projectile fragments, production and interaction cross-sections of heavily ionizing particles emitted from the target fragmentation. Special emphasis will be placed on the analysis of events produced in the central collisions which are selected on the basis of low energy fragments emitted from the target excitation. It woul...

  8. Characteristic time for halo current growth and rotation

    Energy Technology Data Exchange (ETDEWEB)

    Boozer, Allen H., E-mail: ahb17@columbia.edu [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)

    2015-10-15

    A halo current flows for part of its path through the plasma edge and for part through the chamber walls and during tokamak disruptions can be as large as tenths of the plasma current. The primary interest in halo currents is the large force that they can exert on machine components particularly if the toriodal rotation of the halo current resonates with a natural oscillation frequency of the tokamak device. Halo currents arise when required to slow down the growth of a kink that is too unstable to be stabilized by the chamber walls. The width of the current channel in the halo plasma is comparable to the amplitude of the kink, and the halo current grows linearly, not exponentially, in time. The current density in the halo is comparable to that of the main plasma body. The rocket force due to plasma flowing out of the halo and recombining on the chamber walls can cause the non-axisymmetric magnetic structure produced by the kink to rotate toroidally at a speed comparable to the halo speed of sound. Gerhardt's observations of the halo current in NSTX shot 141 687 [Nucl. Fusion 53, 023005 (2013)] illustrate many features of the theory of halo currents and are discussed as a summary of the theory.

  9. Research Progresses of Halo Streams in the Solar Neighborhood

    Science.gov (United States)

    Xi-long, Liang; Jing-kun, Zhao; Yu-qin, Chen; Gang, Zhao

    2018-01-01

    The stellar streams originated from the Galactic halo may be detected when they pass by the solar neighborhood, and they still keep some information at their birth times. Thus, the investigation of halo streams in the solar neighborhood is very important for understanding the formation and evolution of our Galaxy. In this paper, the researches of halo streams in the solar neighborhood are briefly reviewed. We have introduced the methods how to detect the halo streams and identify their member stars, summarized the progresses in the observation of member stars of halo streams and in the study of their origins, introduced in detail how to analyze the origins of halo streams in the solar neighborhood by means of numerical simulation and chemical abundance, and finally discussed the prospects of the LAMOST and GAIA in the research of halo streams in the solar neighborhood.

  10. A novel approach to derive halo-independent limits on dark matter properties

    OpenAIRE

    Ferrer, Francesc; Ibarra, Alejandro; Wild, Sebastian

    2015-01-01

    We propose a method that allows to place an upper limit on the dark matter elastic scattering cross section with nucleons which is independent of the velocity distribution. Our approach combines null results from direct detection experiments with indirect searches at neutrino telescopes, and goes beyond previous attempts to remove astrophysical uncertainties in that it directly constrains the particle physics properties of the dark matter. The resulting halo-independent upper limits on the sc...

  11. Production and supply of radioisotopes with high-energy particle accelerators current status and future directions

    International Nuclear Information System (INIS)

    Srivastava, S.C.; Mausner, L.F.

    1994-01-01

    Although the production of radioisotopes in reactors or in low to medium energy cyclotrons appears to be relatively well established, especially for those isotopes that are routinely used and have a commercial market, certain isotopes can either be made only in high-energy particle accelerators or their production is more cost effective when made this way. These facilities are extremely expensive to build and operate, and isotope production is, in general, either not cost-effective or is in conflict with their primary mandate or missions which involve physics research. Isotope production using high-energy accelerators in the US, therefore, has been only an intermittent and parasitic activity. However, since a number of isotopes produced at higher energies are emerging as being potentially useful for medical and other applications, there is a renewed concern about their availability in a continuous and reliable fashion. In the US, in particular, the various aspects of the prediction and availability of radioisotopes from high-energy accelerators are presently undergoing a detailed scrutiny and review by various scientific and professional organizations as well as the Government. A number of new factors has complicated the supply/demand equation. These include considerations of cost versus needs, reliability factors, mission orientation, research and educational components, and commercial viability. This paper will focus on the present status and projected needs of radioisotope production with high-energy accelerators in the US, and will compare and examine the existing infrastructure in other countries for this purpose

  12. Generalized Boltzmann equations for on-shell particle production in a hot plasma

    International Nuclear Information System (INIS)

    Jakovac, A.

    2002-01-01

    A novel refinement of the conventional treatment of Kadanoff-Baym equations is suggested. In addition to the Boltzmann equation, another differential equation is used for calculating the evolution of the nonequilibrium two-point function. Although it was usually interpreted as a constraint on the solution of the Boltzmann equation, we argue that its dynamics is relevant to the determination and resummation of the particle production cut contributions. The differential equation for this new contribution is illustrated in the example of the cubic scalar model. The analogue of the relaxation time approximation is suggested. It results in the shift of the threshold location and in a smearing out of the nonanalytic threshold behavior of the spectral function. The possible consequences for the dilepton production are discussed

  13. Characteristics of particle production in high energy nuclear collisions a model-based analysis

    CERN Document Server

    Guptaroy, P; Bhattacharya, S; Bhattacharya, D P

    2002-01-01

    The present work pertains to the production of some very important negatively charged secondaries in lead-lead and gold-gold collisions at AGS, SPS and RHIC energies. We would like to examine here the role of the particular version of sequential chain model (SCM), which was applied widely in the past in analysing data on various high-energy hadronic collisions, in explaining now the latest findings on the features of particle production in the relativistic nucleus-nucleus collisions. The agreement between the model of our choice and the measured data is found to be modestly satisfactory in cases of the most prominent and abundantly produced varieties of the secondaries in the above-stated two nuclear collisions. (25 refs).

  14. Search for pair-production of long-lived heavy charged particles in $e^+ e^-$ annihilation

    CERN Document Server

    Barate, R.; Decamp, D.; Ghez, Philippe; Goy, C.; Lees, J.P.; Lucotte, A.; Minard, M.N.; Nief, J.Y.; Pietrzyk, B.; Casado, M.P.; Chmeissani, M.; Comas, P.; Crespo, J.M.; Delfino, M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Juste, A.; Martinez, M.; Miquel, R.; Mir, L.M.; Orteu, S.; Padilla, C.; Park, I.C.; Pascual, A.; Perlas, J.A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; De Palma, M.; Gelao, G.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Alemany, R.; Bazarko, A.O.; Becker, U.; Bright-Thomas, P.; Cattaneo, M.; Cerutti, F.; Dissertori, G.; Drevermann, H.; Forty, R.W.; Frank, M.; Hagelberg, R.; Hansen, J.B.; Harvey, John; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Lutters, G.; Mato, P.; Minten, A.; Moneta, L.; Pacheco, A.; Pusztaszeri, J.F.; Ranjard, F.; Rizzo, G.; Rolandi, Gigi; Schlatter, D.; Schmitt, M.; Schneider, O.; Tejessy, W.; Tomalin, I.R.; Wachsmuth, H.; Wagner, A.; Ajaltouni, Z.; Barres, A.; Boyer, C.; Falvard, A.; Ferdi, C.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rosnet, P.; Rossignol, J.M.; Fearnley, T.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Nilsson, B.S.; Rensch, B.; Waananen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Blondel, A.; Brient, J.C.; Machefert, F.; Rouge, A.; Rumpf, M.; Valassi, A.; Videau, H.; Focardi, E.; Parrini, G.; Zachariadou, K.; Cavanaugh, R.; Corden, M.; Georgiopoulos, C.; Huehn, T.; Jaffe, D.E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G.P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S.J.; Halley, A.W.; Knowles, I.G.; Lynch, J.G.; O'Shea, V.; Raine, C.; Scarr, J.M.; Smith, K.; Teixeira-Dias, P.; Thompson, A.S.; Thomson, Evelyn J.; Thomson, F.; Turnbull, R.M.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Schmidt, M.; Sommer, J.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Dornan, P.J.; Girone, M.; Goodsir, S.; Martin, E.B.; Morawitz, P.; Moutoussi, A.; Nash, J.; Sedgbeer, J.K.; Stacey, A.M.; Williams, M.D.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A.P.; Bowdery, C.K.; Colrain, P.; Crawford, G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.; Sloan, T.; Whelan, E.P.; Williams, M.I.; Hoffmann, C.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J.J.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Coyle, P.; Diaconu, C.; Konstantinidis, N.; Leroy, O.; Motsch, F.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Tilquin, A.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Berlich, R.; Blum, W.; Buescher, Volker; Dietl, H.; Ganis, G.; Gotzhein, C.; Kroha, H.; Lutjens, G.; Lutz, G.; Manner, W.; Moser, H.G.; Richter, Robert, 1; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, Richard Dante; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, P.; Hocker, Andreas; Jacholkowska, A.; Jacquet, M.; Kim, D.W.; Le Diberder, F.; Lefrancois, J.; Lutz, A.M.; Nikolic, Irina; Schune, M.H.; Simion, S.; Tournefier, E.; Veillet, J.J.; Videau, I.; Zerwas, D.; Azzurri, P.; Bagliesi, Giuseppe; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M.A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Giassi, A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P.S.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciaba, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Venturi, A.; Verdini, P.G.; Blair, G.A.; Bryant, L.M.; Chambers, J.T.; Gao, Y.; Green, M.G.; Medcalf, T.; Perrodo, P.; Strong, J.A.; von Wimmersperg-Toeller, J.H.; Botterill, D.R.; Clifft, R.W.; Edgecock, T.R.; Haywood, S.; Maley, P.; Norton, P.R.; Thompson, J.C.; Wright, A.E.; Bloch-Devaux, Brigitte; Colas, P.; Fabbro, B.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Rosowsky, A.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S.N.; Dann, J.H.; Kim, H.Y.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Boswell, R.; Brew, C.A.J.; Cartwright, S.; Combley, F.; Kelly, M.S.; Lehto, M.; Newton, W.M.; Reeve, J.; Thompson, L.F.; Affholderbach, K.; Boehrer, Armin; Brandt, S.; Cowan, G.; Foss, J.; Grupen, C.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Putz, J.; Rothberg, J.; Wasserbaech, S.; Williams, R.W.; Armstrong, S.R.; Charles, E.; Elmer, P.; Ferguson, D.P.S.; Gonzalez, S.; Greening, T.C.; Hayes, O.J.; Hu, H.; Jin, S.; McNamara, P.A., III; Nachtman, J.M.; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Walsh, J.; Wu, S.L.; Wu, X.; Yamartino, J.M.; Zobernig, G.

    1997-01-01

    A search for pair-production of long-lived, heavy, singly-charged particles has been performed with data collected by the ALEPH detector at a centre-of-mass energy of 172 GeV. Data at \\sqrt{s} = 161, 136, and 130 GeV are also included to improve the sensitivity to lower masses. No candidate is found in the data. A model-independent 95 % confidence level upper limit on the production cross section at 172 GeV of 0.2-0.4 pb is derived for masses between 45 and 86 GeV/c^2. This cross section limit implies, assuming the MSSM, a lower limit of 67 (69) GeV/c^2 on the mass of right- (left-) handed long-lived scalar taus or scalar muons and of 86 GeV/c^2 on the mass of long-lived charginos.

  15. Inclusive neutral particle production in anti pp interactions at 22.4 GeV/c

    International Nuclear Information System (INIS)

    Boos, E.G.; Samojlov, V.V.; Takibaev, Zh.S.

    1978-01-01

    The differential distributions over longitudinal and transvers Feynman variables for inclusive γ, Ksub(s)sup(0), Λ production in anti pp interactions at 22.4 GeV/c are presented. The rapidity distributions in the c.m.s. for γ and K 0 /K 0 particles are well described by the quark-antiquark fusion model. In the central region there is some evidence for scaling behaviour of the invariant differential cross sections F for the anti pp → γ+all in the range from 22.4 GeV/c to 100 GeV/c while for the K 0 / K 0 tilde production Frises in this energy interval. A non-zero Λ polarization of -0.414+-0.206 was measured

  16. Coherent production of {epsilon}{sup +} particles in crystal using proton beam from SSC

    Energy Technology Data Exchange (ETDEWEB)

    Okorokov, V.V.; Dubin, A.Yu. [ITER, Moscow, (Russian Federation)

    1995-05-01

    The unique possibilities of the SSC can be ideally used for a new generation of coherent generation experiments with relativistic protons which require 20 Tev energy of the incident beam. The availability of 20 Tev proton beam at SSC allows new experiments on coherent production of {var_epsilon}{sup +} particle by relativistic proton in crystal. Experiment carried out at low energies can now be extended with protons in very narrow energy region (resonance energy, which easy can be calculated) using the new accelerator facilities at SSC. We propose to study coherent production via the Coulomb field of the cristal atoms to excite the transition p + {gamma}{implies} {var_epsilon} {sup +} (1189).

  17. Impacts of Limestone Multi-particle Size on Production Performance, Egg Shell Quality, and Egg Quality in Laying Hens

    Directory of Open Access Journals (Sweden)

    X. Y. Guo

    2012-06-01

    Full Text Available This experiment was conducted to evaluate the effects of single or multi-particle size limestone on the egg shell quality, egg production, egg quality and feed intake in laying hens. A total of 280 laying hens (ISA brown were used in this 10-wk trial. Laying hens were randomly assigned to 4 treatments with 14 replications per treatment and 5 adjacent cages as a replication (hens were caged individually. The experimental treatments were: i L, basal diet+10% large particle limestone; ii LS1, basal diet+8% large particle limestone+2% small particle limestone; iii LS2, basal diet+6% large particle limestone+4% small particle limestone; iv S, basal diet+10% small particle limestone. The egg production was unaffected by dietary treatments. The egg weight in S treatment was lighter than other treatments (p<0.05. The egg specific gravity in S treatment was lower than other treatments (p<0.05. The eggshell strength and eggshell thickness in S treatment were decreased when compared with other dietary treatments (p<0.05. The laying hens in LS1 and LS2 treatment had a higher average feed intake than the other two treatments (p<0.05. Collectively, the dietary multi-particle size limestone supplementation could be as efficient as large particle size limestone.

  18. A GIANT RADIO HALO IN THE MASSIVE AND MERGING CLUSTER ABELL 1351

    International Nuclear Information System (INIS)

    Giacintucci, S.; Venturi, T.; Cassano, R.; Dallacasa, D.; Brunetti, G.

    2009-01-01

    We report on the detection of diffuse radio emission in the X-ray luminous and massive galaxy cluster A 1351 (z = 0.322) using archival Very Large Array data at 1.4 GHz. Given its central location, morphology, and Mpc-scale extent, we classify the diffuse source as a giant radio halo. X-ray and weak lensing studies show A 1351 to be a system undergoing a major merger. The halo is associated with the most massive substructure. The presence of this source is explained assuming that merger-driven turbulence may re-accelerate high-energy particles in the intracluster medium and generate diffuse radio emission on the cluster scale. The position of A 1351 in the log P 1.4GHz -log L X plane is consistent with that of all other radio-halo clusters known to date, supporting a causal connection between the unrelaxed dynamical state of massive (>10 15 M sun ) clusters and the presence of giant radio halos.

  19. Hydrodynamical simulations of coupled and uncoupled quintessence models - I. Halo properties and the cosmic web

    Science.gov (United States)

    Carlesi, Edoardo; Knebe, Alexander; Lewis, Geraint F.; Wales, Scott; Yepes, Gustavo

    2014-04-01

    We present the results of a series of adiabatic hydrodynamical simulations of several quintessence models (both with a free and an interacting scalar field) in comparison to a standard Λ cold dark matter cosmology. For each we use 2 × 10243 particles in a 250 h-1 Mpc periodic box assuming 7-year Wilkinson Microwave Anisotropy Probe cosmology. In this work we focus on the properties of haloes in the cosmic web at z = 0. The web is classified into voids, sheets, filaments and knots depending on the eigenvalues of the velocity shear tensor, which are an excellent proxy for the underlying overdensity distribution. We find that the properties of objects classified according to their surrounding environment show a substantial dependence on the underlying cosmology; for example, while Vmax shows average deviations of ≈5 per cent across the different models when considering the full halo sample, comparing objects classified according to their environment, the size of the deviation can be as large as 20 per cent. We also find that halo spin parameters are positively correlated to the coupling, whereas halo concentrations show the opposite behaviour. Furthermore, when studying the concentration-mass relation in different environments, we find that in all cosmologies underdense regions have a larger normalization and a shallower slope. While this behaviour is found to characterize all the models, differences in the best-fitting relations are enhanced in (coupled) dark energy models, thus providing a clearer prediction for this class of models.

  20. Is Sextans dwarf galaxy in a scalar field dark matter halo?

    International Nuclear Information System (INIS)

    Lora, V.; Magaña, Juan

    2014-01-01

    The Bose-Einstein condensate/scalar field dark matter model, considers that the dark matter is composed by spinless-ultra-light particles which can be described by a scalar field. This model is an alternative model to the Λ-cold dark matter paradigm, and therefore should be studied at galactic and cosmological scales. Dwarf spheroidal galaxies have been very useful when studying any dark matter theory, because the dark matter dominates their dynamics. In this paper we study the Sextans dwarf spheroidal galaxy, embedded in a scalar field dark matter halo. We explore how the dissolution time-scale of the stellar substructures in Sextans, constrain the mass, and the self-interacting parameter of the scalar field dark matter boson. We find that for masses in the range (0.12< m φ <8) ×10 -22 eV, scalar field dark halos without self-interaction would have cores large enough to explain the longevity of the stellar substructures in Sextans, and small enough mass to be compatible with dynamical limits. If the self-interacting parameter is distinct to zero, then the mass of the boson could be as high as m φ ≈2×10 -21 eV, but it would correspond to an unrealistic low mass for the Sextans dark matter halo . Therefore, the Sextans dwarf galaxy could be embedded in a scalar field/BEC dark matter halo with a preferred self-interacting parameter equal to zero