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Sample records for intermediate energies pion

  1. Experimental studies of pion-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    1991-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991 under a great from the US Department of Energy. Most of these studies have involved investigations of various pion-nucleus interactions. The work has been carried out both with the LAMPF accelerator at the Los Alamos National Laboratory and with the cyclotron at the Paul Scherrer Institute (PSI) near Zurich, Switzerland. Part of the experimental work involves measurements of new data on double-charge-exchange scattering, using facilities at LAMPF which we helped modify, and on pion absorption, using a new detector system at PSI that covers nearly the full solid-angle region which we helped construct. Other work involved preparation for future experiments using polarized nuclear targets and a new high-resolution spectrometer system for detecting π 0 mesons. We also presented several proposals for works to be done in future years, involving studies related to pi-mesonic atoms, fundamental pion-nucleon interactions, studies of the difference between charged and neutral pion interactions with the nucleon, studies of the isospin structure of pion-nucleus interactions, and pion scattering from polarized 3 He targets. This work is aimed at improving our understanding of the pion-nucleon interaction, of the pion-nucleus interaction mechanism, and of nuclear structure

  2. Pion deuteron scattering at intermediate energies

    International Nuclear Information System (INIS)

    Ferreira, E.M.

    1978-09-01

    A comparison is made of results of calculations of πd elastic scattering cross section using multiple scattering and three-body equations, in relation to their ability to reproduce the experimental data at intermediate energies. It is shown that the two methods of theoretical calculation give quite similar curves for the elastic differential cross sections, and that both fail in reproducing backward scattering data above 200MeV. The new accurate experimental data on πd total cross section as a function of the energy are confronted with the theoretical values obtained from the multiple scattering calculation through the optical theorem. Comparison is made between the values of the real part of the forward amplitude evaluated using dispersion relations and using the multiple scattering method [pt

  3. Intermediate-energy nuclear photoabsorption and the pion optical potential

    International Nuclear Information System (INIS)

    Christillin, P.

    1984-01-01

    Nuclear photoabsorption around the pion threshold is schematised as photoproduction of a pion which undergoes final-stae interaction with the nucleus, accounted for by the pion optical potential. It is shown that real pion photoproduction and exchange effects are naturally described by the same mechanism with a non-static pion. The complementarity of photoabsorption to pion physics and its usefulness in gaining new information about pion-nucleus dynamics are stressed. (author)

  4. Pion- and proton-nucleus interactions at intermediate energy

    International Nuclear Information System (INIS)

    Dehnhard, D.

    1992-12-01

    We report on scattering and reaction experiments on light nuclei using the π-meson and proton beams from the Los Alamos Meson Physics Facility (LAMPF) and the Indiana University Cyclotron Facility (IUCF). Differential cross sections, cross section asymmetries, and angular correlation functions have been measured in order to test models of the reaction mechanism and of nuclear structure. At LAMPF we have measured asymmetries for pion scattering from polarized 13 C which are uniquely sensitive to the isoscalar spin density. In order to determine details of the reaction mechanism, we have obtained approval for a scattering experiment on polarized 3 He for which the nuclear structure is very well known. We have completed data taking for two studies of elastic scattering of π + from 6 Li and l3 C. The detailed differential cross sections from these experiments will be used to constrain theoretical analyses of previous polarization experiments done at the Pierre-Scherrer-Institute (PSI) and at LAMPF. We have analyzed π-triton coincidence events from the 4 He(π,π' t)p reaction and have found evidence for direct triton knockout from 4 He. We have extended these angular correlation measurements to higher energies and to 2 H and 3 He targets. At IUCF we have performed the first 4 He(p,n) experiment at intermediate energies, T p = 100, 147, and 200 MeV, in a search for previously reported narrow states in 4 Li of widths of ∼ 1 MeV. Within the statistics of the data we have found no evidence for such narrow structures

  5. Coherent pion photoproduction from deuterium at intermediate energies

    International Nuclear Information System (INIS)

    Osland, P.; Rej, A.K.

    1975-12-01

    The coherent photoproduction of neutral pions on deuterons is studied at energies around the (3,3) resonance and discuss the effects of the Fermi motion, rescattering and kinematical approximations. The results are very dependent upon what kinematical approximations one adopts for the impulse approximation term, which dominates up to very large angles. Allowing for this uncertainty in the kinematics, our results are in good agreement with the most recent experimental data

  6. Experimental studies of pion-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    1992-01-01

    This report summarizes investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, and at Indiana University (IUCF), as a collaborative effort among several laboratories and universities. The experimental activity at LAMPF involved measurements of new data on pion double-charge-exchange scattering, some initial work on a new Neutral Meson Spectrometer system, a search for deeply-bound pionic atoms, measurements of elastic scattering, and studies of the (n,p) reaction on various nuclei. At PSI measurements of pion quasielastic scattering were carried out, with detection of the recoil proton. Work on the analysis of data from a previous experiment at PSI on pion absorption in nuclei was continued. This experiment involved using a detector system that covered nearly the full solid angle

  7. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    1990-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988--91. Most of these studies have involved investigations of neutron-proton and pion-nucleus interactions. The neutron-proton research is part of a program of studies of interactions between polarized nucleons that we have been involved with for more than ten years. Its purpose has been to help complete the determination of the full set of ten complex nucleon-nucleon amplitudes at energies up to 800 MeV, as well as to continue investigating the possibility of the existence of dibaryon resonances. The give complex isospin-one amplitudes have been fairly well determined, partly as a result of this work. Our work in this period has involved measurements and analysis of data on elastic scattering and total cross sections for polarized neutrons on polarized protons. The pion-nucleus research continues our studies of this interaction in regions where it has not been well explored. One set of experiments includes studies of pion elastic and double-charge-exchange scattering at energies between 300 and 550 MeV, where our data is unique. Another involves elastic and single-charge-exchange scattering of pions from polarized nuclear targets, a new field of research which will give the first extensive set of information on spin-dependent pion-nucleus amplitudes. Still another involves the first set of detailed studies of the kinematic correlations among particles emitted following pion absorption in nuclei

  8. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies: Final report

    International Nuclear Information System (INIS)

    Burleson, G.R.

    1987-01-01

    We are applying for a three-year grant from the US Department of Energy to New Mexico State University to continue its support of our work on experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies, which has been carried out in collaboration with groups from various laboratories and universities. The nucleon-nucleon work is aimed at making measurements that will contribute to a determination of the isospin-zero amplitudes, as well as continuing our investigations of evidence for dibaryon resonances. It is based at the LAMPF accelerator in Los Alamos, New Mexico. Current and planned experiments include measurements of total cross-section differences in pure spin states and of spin parameters in neutron-proton scattering. The pion-nucleus work is aimed at improving our understanding both of the nature of the pion-nucleus interaction and of nuclear structure. It consists of two programs, one based at LAMPF and one based principally at the SIN laboratory in Switzerland. The LAMPF-based work involves studies of large-angle scattering, double-charge-exchange scattering, including measurements at a new energy range above 300 MeV, and a new program of experiments with polarized nuclear targets. The SIN-based work involves studies of quasielastic scattering and absorption, including experiments with a new large-acceptance detector system planned for construction there. We are requesting support to continue the LAMPF-based work at its current level and to expand the SIN-based work to allow for increased involvement in experiments with the new detector system. 57 refs

  9. Low and intermediate energy pion-nucleus interactions in the cascade-exciton model

    International Nuclear Information System (INIS)

    Mashnik, S.G.

    1993-01-01

    A large variety of experimental data on pion-nucleus interactions in the bombarding energy range of 0-3000 MeV, on nucleon-induced pion production and on cumulative nucleon production, when a two-step process of pion production followed by absorption on nucleon pairs within a target is taken into account, are analyzed with the Cascade-Exciton Model of nuclear reactions.Comparison is made with other up-to-date models of these processes. The contributions of different pion absorption mechanisms and the relative role of different particle production mechanisms in these reactions are discussed

  10. Interplay between one-body and two-body dynamics in the subthreshold pion production at intermediate energies

    International Nuclear Information System (INIS)

    Cassing, W.

    1984-12-01

    The role of the time-dependent mean field in subthreshold pion production by first chance nucleon-nucleon collisions is studied for heavy-ion reactions at intermediate energies in a finite two-center shell model. It is found that the energy distribution of the nucleons for overlapping ions can roughly be approximated by shifted groundstate momentum distributions using a quasi-free dispersion relation. The absolute cross sections for the production of neutron pions can be reproduced from 35 MeV/u to 150 MeV/u. (orig.)

  11. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies: Annual progress report, 1988--1989

    International Nuclear Information System (INIS)

    1988-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1988 under a grant from the US Department of Energy. The nucleon-nucleon research has involved studies of interactions between polarized neutrons and polarized protons. Its purpose is to help complete the determination of the nucleon-nucleon amplitudes at energies up to 800 MeV, as part of a program currently in progress at LAMPF, as well as to investigate the possibility of the existence of dibaryon resonances. The pion-nucleus research involves studies of this interaction in regions where it has not been adequately explored. These include experiments on elastic and double charge exchange scattering at energies above the /Delta/(1232) resonance, interactions with polarized nuclear targets, and investigations of pion absorption using a detector covering nearly the full solid angle region. 21 refs., 4 figs

  12. Quasielastic knock out of light fragments from 12C and 16O by intermediate energy pions

    International Nuclear Information System (INIS)

    Abramov, B.M.; Borodin, Yu.A.; Bulychev, S.A.

    2006-01-01

    Using 0.72 GeV s -1 pulse π - -meson beam one studied the quasi-elastic knocking out of deuterons and of tritons from 12 C and 16 O nuclei. One derived the quasi-deuteron intranuclear motion pulse distributions, the residual nucleus excitation energy spectra and the effective number of quasi-deuterons. The parameters of quasi-deuteron intranuclear motion pulse distributions are in line with the measurement results for other beams. The effective numbers of quasi-deuterons in nuclei from 6 Li up to 16 O do not depend on the atomic number. One observed knocking out of tritons from the mentioned nuclei enabling to evaluate the cross section of elastic pion-triton backscattering [ru

  13. Evidence for pion exchange currents in the analysis of the /sup 4/He(p,d)/sup 3/He reaction at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Shepard, J R; Rost, E; Smith, G R [Colorado Univ., Boulder (USA). Nuclear Physics Lab.

    1979-12-01

    Previous unsuccessful analyses of /sup 4/He(p,d)/sup 3/He at intermediate energies have employed densities based directly on the measured e/sup -/ + /sup 4/He elastic scattering. When the effects of pion exchange currents are removed, the resulting DWBA analysis is in qualitative agreement with the experimental data.

  14. Experimental studies of nucleon-nucleon and pion-nucleus interactions at intermediate energies: Progress report, January 1, 1985-December 31, 1987

    International Nuclear Information System (INIS)

    1987-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear and particle physics carried out by New Mexico State University in 1985-87. These studies have involved investigations of nucleon-nucleon and pion-nucleus interactions. They have been carried out at the LAMPF accelerator at the Los Alamos National Laboratory, at the SIN laboratory near Zurich, Switzerland, and at the TRIUMF accelerator in Vancouver, Canada. 86 refs., 5 figs

  15. Measurement of neutron-production double-differential cross sections for intermediate energy pion incident reaction

    International Nuclear Information System (INIS)

    Iwamoto, Yosuke; Shigyo, Nobuhiro; Satoh, Daiki

    2002-01-01

    Neutron-production double-differential cross sections for 870-MeV π + and π - and 2.1-GeV π + mesons incident on iron and lead targets were measured with NE213 liquid scintillators by time-of-flight technique. NE213 liquid scintillators 12.7 cm in diameter and 12.7 cm thick were placed in directions of 15, 30, 60, 90, 120 and 150deg. The typical flight path length was 15 m. Neutron detection efficiencies were derived from the calculation results of SCINFUL and CECIL codes. The experimental results were compared with the JAM code. The double differential cross sections calculated by the JAM code disagree with experimental data at neutron energies below about 30 MeV. JAM overestimates π + -incident neutron-production cross sections in forward angles at neutron energies of 100 to 500 MeV. (author)

  16. Pion- and proton-nucleus interactions at intermediate energy: Progress report, 1 June 1988--31 May 1989

    International Nuclear Information System (INIS)

    Dehnard, D.

    1989-01-01

    Data were taken for elastic scattering of π + and π/sup /minus// at far forward angles as part of our continuing study of this system near [3,3] resonance energies. The work on data reduction of the 4 He (π/sup +-/,π/sup +-/,p) and 12 C(π/sup +-/,π/sup +-/,p) reactions was completed. Comparisons with DWIA predictions for quasifree knockout yield evidence for an interference of two processes: quasifree knockout, and formation and decay of states of good isospin in the giant resonance region. The replay and analysis of our 4 He(p,p') data at 500 and 800 MeV were continued and gave new information on the monopole strength in 4 He. Preparations were made for the pion scattering experiments on polarized 13 C which is scheduled for the summer of 1989

  17. [Intermediate energy nuclear physics

    International Nuclear Information System (INIS)

    1989-01-01

    This report summarizes work in experimental Intermediate Energy Nuclear Physics carried out between October 1, 1988 and October 1, 1989 at the Nuclear Physics Laboratory of the University of Colorado, Boulder, under grant DE-FG02-86ER-40269 with the United States Department of Energy. The experimental program is very broadly based, including pion-nucleon studies at TRIUMF, inelastic pion scattering and charge exchange reactions at LAMPF, and nucleon charge exchange at LAMPF/WNR. In addition, a number of other topics related to accelerator physics are described in this report

  18. Experimental studies of pion-nucleus and nucleon-nucleus interactions at intermediate energies. Progress report, April 1, 1991--March 31, 1994

    International Nuclear Information System (INIS)

    1993-01-01

    This report summarizes the work on experimental research in intermediate energy nuclear physics carried out at New Mexico State University in 1991-94 under a grant from the U.S. Department of Energy. Most of these studies involved investigations of various pion-nucleus interactions and nucleon-nucleus charge-exchange reactions. The work was carried out with the LAMPF accelerator at the Los Alamos National Laboratory and the cyclotrons at the Paul Scherrer Institute (PSI) near Zurich, Switzerland, at Indiana University (IUCF), and at TRIUMF in Vancouver, Canada, as collaborative efforts among several laboratories and universities. We have also worked on plans and preparations for new experiments involving studies of the quark structure of nucleons and nuclei, which would be carried out at Fermilab (FNAL), near Chicago, and at the HERA facility at the DESY laboratory in Hamburg, Germany. The NMSU personnel included two faculty members, five postdoctoral research associates, nine graduate students, and one undergraduate student

  19. Low energy pion--nucleon and pion--deuteron interactions

    International Nuclear Information System (INIS)

    Burman, R.L.

    1975-01-01

    This survey concentrates upon current experiments in the fields of pion-nucleon and pion-deuteron interactions, for low-energy incident pions--below 300 MeV. The discussion is restricted to very recent work. The topics to be covered are: π +- p → π +- p, Elastic Scattering; π +- p → π +- pγ, Bremsstrahlung; π + d → pp, Absorption; π d → π + d, Elastic Scattering; and π + d → π + pn, Breakup. (14 figures) (U.S.)

  20. Analytic approach to the relativistic problem of constructing effective nucleon-nucleon and pion-nucleon interaction operators at low and intermediate energies

    International Nuclear Information System (INIS)

    Safronov, A.N.; Safronov, A.A.

    2006-01-01

    Full text: A nonperturbative character of QCD at low and intermediate energies generates serious mathematical difficulties in describing the dynamics of hadron-hadron interactions in terms quark-gluon degrees of freedom. Therefore much effort has gone in past years into developing QCD-motivated approaches that formulate the theory of strong interaction in terms of hadron degrees of freedom. The path-integral technique together with idea of spontaneous chiral-symmetry breaking leads to Effective Field Theory (EFT) [1]. Unfortunately EFT can be applied to description of hadron-hadron interactions only at very low energies. On the other hand, meson theories of nuclear forces have long since been used to describe the properties of nucleon systems and scattering processes. Now it is not quite clear, up to what distances the meson-exchange pattern of nuclear forces is valid. Recently the new relativistic approach to the problem of constructing effective hadron-hadron interaction operators has been proposed [2-4] on the basis of analytic S-matrix theory and Gelfand-Levitan-Marchenko-Martin methods for solving the inverse quantum scattering problem. In this approach effective potential is defined as a local operator in a partial-wave equation of the quasipotential type such that it generates on-shell relativistic (Feynman) scattering amplitude that has required discontinuities at dynamical cuts. The discontinuities of partial-wave amplitudes are determined by model-independent quantities (renormalized vertex constants and amplitudes of subprocesses involving on-mass-shell particles off the physical region) and can be calculated by methods of relativistic quantum field theory within various dynamical approaches. In particular, EFT can be used to calculate the discontinuities across dynamical-cut segments closest to the physical region. In [2-4] we have examined the basic features of the proposed approach. Attention has been given primarily to analyzing the new mechanism of

  1. Pion form factor in QCD at intermediate momentum transfers

    Science.gov (United States)

    Braun, V. M.; Khodjamirian, A.; Maul, M.

    2000-04-01

    We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of the pion distribution amplitude and allows us to estimate the deviation: [∫du/uφπ(u)]/[∫du/uφasπ(u)]=1.1+/-0.1 at the scale of 1 GeV. Special attention is paid to the precise definition and interplay of soft and hard contributions at intermediate momentum transfer, and to the matching of the sum rule to the perturbative QCD prediction. We observe a strong numerical cancellation between the soft (end-point) contribution and power-suppressed hard contributions of higher twist, so that the total nonperturbative correction to the usual PQCD result turns out to be of the order of 30% for Q2~1 GeV2.

  2. Measuring pion beta decay with high-energy pion beams

    International Nuclear Information System (INIS)

    McFarlane, W.K.; Hoffman, C.M.

    1993-01-01

    Improved measurements of the pion beta decay rate are possible with an intense high-energy pion beam. The rate for the decay π + → π 0 e + vε is predicted by the Standard Model (SM) to be R(π + → π 0 e + vε) = 0.3999±0.0005 s -1 . The best experimental number, obtained using in-flight decays, is R(π + → π 0 e + vε) = 0.394 ± 0.015 s -1 . A precise measurement would test the SM by testing the unitarity of the Cabibbo-Kobayashi-Maskawa matrix for which one analysis of the nuclear beta decay data has shown a 0.4% discrepancy. Several nuclear correction factors, needed for nuclear decay, are not present for pion beta decay, so that an experiment at the 0.2% level would be a significant one. Detailed study of possible designs will be needed, as well as extensive testing of components. The reduction of systematic errors to the 0.1% level can only be done over a period of years with a highly stable apparatus and beam. At a minimum, three years of occupancy of a beam line, with 800 hours per year, would be required

  3. [Studies in intermediate energy nuclear physics

    International Nuclear Information System (INIS)

    Peterson, R.J.

    1993-01-01

    This report summarizes work carried out between October 1, 1992 and September 30, 1993 at the Nuclear Physics Laboratory of the University of Colorado, Boulder. The experimental program in intermediate-energy nuclear physics is very broadly based; it includes pion-nucleon and pion-nucleus studies at LAMPF and TRIUMF, kaon-nucleus scattering at the AGS, and equipment development for experiments at the next generation of accelerator facilities

  4. Physics with low energy pions and muons

    International Nuclear Information System (INIS)

    Konijn, J.

    1981-01-01

    This document is a collection of texts used for a course of lectures given by the author at the Technical University of Delft (NL) in 1981. It is therefore a comprehensive, Dutch language, review article starting with the discovery of pions and muons, describing their properties and finally discussing their applications in low energy physics. (C.F.)

  5. Pion photoproduction in nucleons at low energies

    International Nuclear Information System (INIS)

    Carvalho, F.A.B.R. de.

    1983-01-01

    A new semiphenomenological analysis of the multipoles for pion photoproduction from nucleons, in the region of the first π-N resonance is presented. Through an energy dependent model, multipoles with isospin 1/2 and 3/2 and total angular momentum J [pt

  6. Solving the relativistic inverse scattering problem on the basis of n/d equations and application of the resulting solution to analysis of pion-nucleon interaction at low and intermediate energies

    International Nuclear Information System (INIS)

    Safronov, A.N.

    2007-01-01

    Full text: The pion-nucleon dynamics is one of the most fundamental problems in nuclear and particle physics. It is now widely believed that QCD is fundamental theory of strong interactions. On this basis all hadron-hadron interactions are completely determined by the underlying quark-gluon dynamics. However, due to the formidable mathematical problems raised by the non-perturbative character of QCD at low and intermediate energies, we are still far from a quantitative understanding hadron-hadron interactions from this point of view. Recently the relativistic approaches to constructing effective interaction operators between strongly interacting composite particles has been proposed on the basis of analytic S-matrix theory and methods for solving the inverse quantum scattering problem. The kernel of Marchenko equation in theory of inverse scattering problem can be expressed in terms of the discontinuity of the partial wave amplitude on dynamic cut in the complex s=k 2 plane, k being the relative momentum of colliding particles. The discontinuities of partial-wave amplitudes are determined by model-independent quantities (renormalized vertex constants and amplitudes of sub-processes involving on-mass-shell particles off physical region) and can be calculated by methods of relativistic quantum field theory within various dynamical approaches. In particular, effective field theory can be used to calculate the discontinuities across dynamical cuts closest to physical region. In present work a new manifestly Poincare-invariant approach to solving the inverse scattering problem is developed with allowance for inelasticity effects. The equations of the N/D method are used as dynamical equations in this approach. With the help of N/D-equations it was earlier shown that solution of a scattering problem in case of nonzero angular momentum does not exist for arbitrary discontinuity of partial-wave amplitude. The method is elaborated allowing to determine contributions of

  7. Low-energy photo- and electroproduction for physical pions

    International Nuclear Information System (INIS)

    MacMullen, J.T.

    1979-02-01

    The Ward identities of current algebra are combined with gauge invariance constraints, on-shell PCAC and the Bjorken limit to obtain the low-energy expressions of the pion photo- and electroproduction invariant amplitudes for physical pions

  8. Low energy scattering with a nontrivial pion

    International Nuclear Information System (INIS)

    Fariborz, Amir H.; Jora, Renata; Schechter, Joseph

    2007-01-01

    An earlier calculation in a generalized linear sigma model showed that the well-known current algebra formula for low energy pion-pion scattering held even though the massless Nambu Goldstone pion contained a small admixture of a two-quark two-antiquark field. Here we turn on the pion mass and note that the current algebra formula no longer holds exactly. We discuss this small deviation and also study the effects of a SU(3) symmetric quark mass type term on the masses and mixings of the eight SU(3) multiplets in the model. We calculate the s-wave scattering lengths, including the beyond current algebra theorem corrections due to the scalar mesons, and observe that the effect of the scalar mesons is to improve the agreement with experiment. In the process, we uncover the way in which linear sigma models give controlled corrections (due to the presence of scalar mesons) to the current algebra scattering formula. Such a feature is commonly thought to exist only in the nonlinear sigma model approach

  9. Low energy pion-pion phase shifts from chiral perturbation theory

    International Nuclear Information System (INIS)

    Borges, J. Sa; Barbosa, J. Soares; Oguri, V.

    1997-01-01

    The low energy pion-pion S- and P- experimental phase-shifts are fitted with chiral perturbation theory (Ch PT) amplitude. The low energy pion-pion S- and P- experimental phase-shifts. The parameters l 1 and l 2 of the one loop corrected amplitude are fixed and the corresponding values of the scattering lengths are calculated. We propose that the present method is the best way to fix Ch P T parameters. The unitarization program of current algebra is also discussed. (author)

  10. Low-energy pion-nucleon scattering

    International Nuclear Information System (INIS)

    Gibbs, W.R.; Ai, L.; Kaufmann, W.B.

    1998-01-01

    An analysis of low-energy charged pion-nucleon data from recent π ± p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f 2 =0.0756±0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P 31 and P 13 partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the Σ term. Off-shell amplitudes are also provided. copyright 1998 The American Physical Society

  11. Low energy pion detection by a silicon surface barrier telescope

    International Nuclear Information System (INIS)

    Sealock, R.M.; Caplan, H.S.; Leung, M.K.

    1978-01-01

    Four telescopes of three (2-ΔE, 1-E) silicon surface barrier detectors each, mounted in the focal plane of a magnetic spectrometer, have been used to detect positive pions in the energy range from 4.7-17.9 MeV and negative pions from 14.1-17.9 MeV. Positive pions from 4.7-12.7 MeV were stopped in the third detector while positive and negative pions from 14.1-17.9 MeV were detected in transmission. For energies greater than 7.4 MeV aluminum moderators were placed in front of the first detector to degrade the pion energy. Energy spectra show well resolved pion peaks with extremely low background. Double differential cross sections for the 12 C(e,π + ) 12 B,e' reaction have been measured. (Auth.)

  12. Low energy pion-16O scattering

    International Nuclear Information System (INIS)

    Wafelbakker, C.K.

    1981-01-01

    In spite of some outward appearances, the modern microscopic theories of the pion-nucleus (πA) interaction are not fundamentally very different from each other. They can all be derived from the same source, multiple-scattering theory. They all treat the first-order optical potential in a comparatively detailed way and in all of them it is necessary to incorporate higher-order effects in general and pion-annihilation in particular phenomenologically. Basically the same physical features can be embodied in all of them. The presentation of the theoretical scheme underlying the present thesis is designed to stress this conceptual unity of current πA theory. In this thesis the methods developed by De Kam to incorporate Pauli- and binding-corrections to the impulse-approximation first-order optical potential for 4 He are extended to a more complicated nucleus, 16 O, for the first time. In concreto two situations are considered: π- 16 O scattering at energies below nucleon-knockout threshold (13.5 MeV) - 7 and 12 MeV - and at energies 40 and 49.7 MeV, above nucleon-knockout threshold but still well within the low-energy region. (Auth.)

  13. Intermediate-energy nuclear chemistry workshop

    Energy Technology Data Exchange (ETDEWEB)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

  14. Intermediate-energy nuclear chemistry workshop

    International Nuclear Information System (INIS)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities

  15. Pion-nucleon interactions in low energy region

    International Nuclear Information System (INIS)

    Hiroshige, Noboru; Tsujimura, Tadakuni.

    1977-01-01

    Pion-nucleon interactions in low energy region (below 320 MeV in kinetic energy) are investigated on the basis of the one-particle-exchange model. The model is directly compared with the experimental data, i.e., differential cross sections and recoil nucleon polarizations, since phase shifts have not been uniquely determined. It is shown that these experimental data can be well reproduced by taking account of N (nucleon), Δ 33 , N 11 , N 13 , rho, f 0 and S (scalar meson) in the intermediate state. Some comments are given on the coupling constants which are determined so as to minimize chi-squared value (chi 2 ). Our predicted phase shifts for s-, p- and d-waves are also compared with other authors'. (auth.)

  16. Role of compound nuclei in intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1988-05-01

    Hot compound nuclei are frequently produced in intermediate-energy reactions through a variety of processes. Their decay is shown to be an important and at times dominant source of complex fragments, high energy-gamma rays, and even pions

  17. Low energy theorems in pion production

    International Nuclear Information System (INIS)

    Holstein, B.R.; Washington Univ., Seattle, WA

    1992-01-01

    Considerable activity-both theoretical and experimental-has recently taken place involving the threshold and near threshold of pion photo- and electroproduction. This activity is herein summarized and a program for future work is outlined

  18. Experiments in intermediate energy physics

    International Nuclear Information System (INIS)

    Dehnhard, D.

    2003-01-01

    Research in experimental nuclear physics was done from 1979 to 2002 primarily at intermediate energy facilities that provide pion, proton, and kaon beams. Particularly successful has been the work at the Los Alamos Meson Physics Facility (LAMPF) on unraveling the neutron and proton contributions to nuclear ground state and transition densities. This work was done on a wide variety of nuclei and with great detail on the carbon, oxygen, and helium isotopes. Some of the investigations involved the use of polarized targets which allowed the extraction of information on the spin-dependent part of the triangle-nucleon interaction. At the Indiana University Cyclotron Facility (IUCF) we studied proton-induced charge exchange reactions with results of importance to astrophysics and the nuclear few-body problem. During the first few years, the analysis of heavy-ion nucleus scattering data that had been taken prior to 1979 was completed. During the last few years we created hypernuclei by use of a kaon beam at Brookhaven National Laboratory (BNL) and an electron beam at Jefferson Laboratory (JLab). The data taken at BNL for a study of the non-mesonic weak decay of the A particle in a nucleus are still under analysis by our collaborators. The work at JLab resulted in the best resolution hypernuclear spectra measured thus far with magnetic spectrometers

  19. Experiments in intermediate energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Dehnhard, D.

    2003-02-28

    Research in experimental nuclear physics was done from 1979 to 2002 primarily at intermediate energy facilities that provide pion, proton, and kaon beams. Particularly successful has been the work at the Los Alamos Meson Physics Facility (LAMPF) on unraveling the neutron and proton contributions to nuclear ground state and transition densities. This work was done on a wide variety of nuclei and with great detail on the carbon, oxygen, and helium isotopes. Some of the investigations involved the use of polarized targets which allowed the extraction of information on the spin-dependent part of the triangle-nucleon interaction. At the Indiana University Cyclotron Facility (IUCF) we studied proton-induced charge exchange reactions with results of importance to astrophysics and the nuclear few-body problem. During the first few years, the analysis of heavy-ion nucleus scattering data that had been taken prior to 1979 was completed. During the last few years we created hypernuclei by use of a kaon beam at Brookhaven National Laboratory (BNL) and an electron beam at Jefferson Laboratory (JLab). The data taken at BNL for a study of the non-mesonic weak decay of the A particle in a nucleus are still under analysis by our collaborators. The work at JLab resulted in the best resolution hypernuclear spectra measured thus far with magnetic spectrometers.

  20. Intermediate energy data

    International Nuclear Information System (INIS)

    Koning, A.J.; Fukahori, T.; Hasegawa, A.

    1998-01-01

    Subgroup 13 (SG13) on Intermediate Energy Nuclear data was formed by NEA Nuclear Science Committee to solve common problems of these types of data for nuclear applications. An overview is presented in this final report of the present activities of SG13, including data needs, high-priority nuclear data request list (nuclides), compilation of experimental data, specialists meetings and benchmarks, data formats and data libraries. Some important accomplishments are summarized, and recommendations are presented. (R.P.)

  1. High-energy pion beams: Problems and prospects

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1992-01-01

    The investigation of relatively unexplored research areas with high energy pion beams requires new facilities. Presently existing meson factories such as LAMPF, TRIUMF and PSI provide insufficient pion fluxes above the 3,3 resonance region for access to topics such as strangeness production with the (π, K) reaction, baryon resonances, rare meson decays, and nuclear studies with penetrating pion beams. The problems and prospects of useful beams for these studies will be reviewed, both for existing facilities such as the AGS and KEK, and for possible future facilities like KAON and PILAC

  2. Intermediate energy proton and light-ion scattering

    International Nuclear Information System (INIS)

    Moss, J.M.

    1981-01-01

    A review is presented of recent (1979-81) developments in the field of intermediate-energy proton and light-ion scattering from nuclei. New theoretical and calculational techniques of particular interest to experimentalists are discussed. Emphasis is placed on topics in nuclear structure physics - giant resonances, pion-condensation precursor phenomena, and polarization transfer (spin-flip) experiments - where intermediate energy proton and light-ion scattering has made new and unique contributions

  3. The TRIUMF low energy pion spectrometer and channel

    International Nuclear Information System (INIS)

    Sobie, R.J.; Drake, T.E.; Barnett, B.M.; Erdman, K.L.; Gyles, W.; Johnson, R.R.; Roser, H.W.; Tacik, R.; Blackmore, E.W.; Gill, D.R.

    1983-08-01

    A low energy pion spectrometer has been developed for use with the TRIUMF M13 pion channel. The combined channel and spectrometer resolution is presently 1.1 MeV at T = 50 MeV. This is limited by the amount of gas and detector material in the spectrometer in addition to the inherent resolution of the channel. Improvements to both the spectrometer and channel are discussed

  4. Nuclear structure at intermediate energies

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1991-01-01

    The theme that unites the sometimes seemingly disparate experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in their radiative decays in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of our BNL experiments E810, E854, as well as our approved experiment at RHIC), -- all these projects share this common goal. Our other experiments represent different approaches to the same broad undertaking. LAMPF E1097 will provide definitive answers to the question of the spin dependence of the inelastic channel of pion production in the n-p interaction. FNAL E683 may well open a new field of investigation in nuclear physics: that of just how quarks and gluons interact with nuclear matter as they transverse nuclei of different sizes. In most all of the experiments mentioned above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are unavailable to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do

  5. Pion interactions at medium energies: Progress report

    International Nuclear Information System (INIS)

    Allred, J.C.; Goodman, C.

    1970-01-01

    Accelerating equipment, radiation detectors, and data acquisition equipment are described for a proposed study of 300 MeV pion scattering on deuterium targets at the Space Radiation Effects Laboratory in Newport News, Virginia. A key concept in the proposed program of measurements is a proposal by G.C Phillips to develop planes of proportional counters compatible with fast scintillation logic from pre-existing counters. The impetus for the research is the eventual use of the LAMPF accelerator at Los Alamos

  6. Pion linac as an energy-tagged ν source

    Directory of Open Access Journals (Sweden)

    T. Goldman

    2008-12-01

    Full Text Available The energy spectrum and flux of neutrinos from a linear pion accelerator are calculated analytically under the assumption of a uniform accelerating gradient. The energy of a neutrino from this source reacting in a detector can be determined from timing and event position information.

  7. The pion (muon) energy production cost in muon catalyzed fusion

    International Nuclear Information System (INIS)

    Fadeev, N.G.; Solov'ev, M.I.

    1995-01-01

    The article presents the main steps in the history of the study on the muon catalysis of nuclear fusion. The practical application of the muon catalysis phenomenon to obtain the energy gain is briefly discussed. The details of the problem to produce pion (muon) yield with minimal energy expenses have been considered. 31 refs., 4 tabs

  8. Multiplicity correlations of intermediate-mass fragments with pions and fast protons in 12C + 197AU

    International Nuclear Information System (INIS)

    Turzo, K.; Begemann-Blaich, M.L.; Auger, G.

    2003-12-01

    Low-energy π + (E π 12 C+ 197 Au collisions at incident energies from 300 to 1800 MeV per nucleon were detected with the Si-Si(Li)-CsI(Tl) calibration telescopes of the INDRA multidetector. The inclusive angular distributions are approximately isotropic, consistent with multiple rescattering in the target spectator. The multiplicity correlations of the low-energy pions and of energetic protons (E p >or ≤ 150 MeV) with intermediate-mass fragments were determined from the measured coincidence data. The deduced correlation functions 1 + R ∼ 1.3 for inclusive event samples reflect the strong correlations evident from the common impact-parameter dependence of the considered multiplicities. For narrow impact-parameter bins (based on charged-particle multiplicity), the correlation functions are close to unity and do not indicate strong additional correlations. Only for pions at high particle multiplicities (central collisions) a weak anticorrelation is observed, probably due to a limited competition between these emissions. Overall, the results are consistent with the equilibrium assumption made in statistical multifragmentation scenarios. Predictions obtained with intranuclear cascade models coupled to the statistical multifragmentation model are in good agreement with the experimental data. (orig.)

  9. Workshop on hadron structure from photo-reactions at intermediate energies: Proceedings

    International Nuclear Information System (INIS)

    Nathan, A.M.; Sandorfi, A.M.

    1992-01-01

    This report contains papers on the following topics: The proton compton effect: Recent measurements of the electric and magnetic polorizabilities of the proton; experiments on the electric polarizability of the neutron; chiral symmetry and nucleon polarizabilities; chiral model predictions for electromagnetic polarizabilities of the nucleon, a consumer report; the polarizabilities of bound nucleons; nucleon polarizability in free space and in nuclear matter; mechanisms of photon scattering on nucleons at intermediate energies; pion polarizabilities in chiral perturbation theory; pion polarizabilities and the shielding of σ(700)-meson exchange in γγ→ππ processes; pion and kaon polarizabilities in the quark confinement model; radiative pion photoproduction and pion polarizabilities; pion and sigma polarizabilities and radiative transitions; the quadrupole amplitude in the γΝ-Δ transition; pion photoproduction and the γΝ-Δ amplitudes; effective- lagrangians, Watson's theorem, and the E2/M1 mixing ratio in the excitation of the delta resonance; new measurements of the p(rvec γ, π o ) reaction; multipole analyses and photo-decay couplings at intermediate energies; compton scattering off the proton; connections between compton scattering and pion photoproduction in the delta region; single-pion electroproduction and the transverse one-half and scalar helicity transition form factors; relativistic effects, QCD mixing angles, and Ν → Νγ and Δ → γΝ transition form factors; electroproduction studies of the Ν → Δ transition at bates and CEBAF

  10. Workshop on hadron structure from photo-reactions at intermediate energies: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Nathan, A.M.; Sandorfi, A.M. [eds.

    1992-10-01

    This report contains papers on the following topics: The proton compton effect: Recent measurements of the electric and magnetic polorizabilities of the proton; experiments on the electric polarizability of the neutron; chiral symmetry and nucleon polarizabilities; chiral model predictions for electromagnetic polarizabilities of the nucleon, a consumer report; the polarizabilities of bound nucleons; nucleon polarizability in free space and in nuclear matter; mechanisms of photon scattering on nucleons at intermediate energies; pion polarizabilities in chiral perturbation theory; pion polarizabilities and the shielding of {sigma}(700)-meson exchange in {gamma}{gamma}{yields}{pi}{pi} processes; pion and kaon polarizabilities in the quark confinement model; radiative pion photoproduction and pion polarizabilities; pion and sigma polarizabilities and radiative transitions; the quadrupole amplitude in the {gamma}{Nu}-{Delta} transition; pion photoproduction and the {gamma}{Nu}-{Delta} amplitudes; effective- lagrangians, Watson`s theorem, and the E2/M1 mixing ratio in the excitation of the delta resonance; new measurements of the p({rvec {gamma}}, {pi}{sup o}) reaction; multipole analyses and photo-decay couplings at intermediate energies; compton scattering off the proton; connections between compton scattering and pion photoproduction in the delta region; single-pion electroproduction and the transverse one-half and scalar helicity transition form factors; relativistic effects, QCD mixing angles, and {Nu} {yields} {Nu}{gamma} and {Delta} {yields} {gamma}{Nu} transition form factors; electroproduction studies of the {Nu} {yields} {Delta} transition at bates and CEBAF.

  11. The quasi deuteron model for low energy pion absorption

    International Nuclear Information System (INIS)

    Gouweloos, M.

    1986-01-01

    In this thesis pion absorption in complex nuclei is studied in the quasi-deuteron model in which the pion is absorbed on a nucleon pair in the nucleus. The mechanism is studied in the low-energy domain since then the in-medium (pi→NN) operator turns out to be of simple character. In Ch. 2 and 3 this operator is constructed and analytical expressions are derived for (pi,NN) distributions in a plane wave impulse approximation for nuclei. The results turn out to be very useful for developing insight in the possibilities inherent in the QDM and the interpretation of the results in later chapters. Ch. 4 to 6 are devoted to the more realistic distorted wave calculations. In Ch. 4 the formal framework is presented and the calculational details are discussed. Ch.5 and 6 contain the comparison to stopped pion and in-flight data respectively. In Ch. 7 the main results are summarized. (Auth.)

  12. Low-energy photo- and electroproduction for physical pions

    International Nuclear Information System (INIS)

    MacMullen, J.T.

    1979-02-01

    The background resonance Δ(1230), Nsup(*)(1520), Nsup(*)(1470) and Nsup(*)(1535)pion and axial-vector amplitudes are first calculated in the soft pion and on-shell configuration, respectively. Then a comparison is made with the usual soft pion theorems and on-shell low-energy expansions of current algebra as worked out in the previous paper. The agreement is good and we also deduce a nucleon dipole form factor axial-vector mass of msub(A)approximately equal to 1,23 GeV. Finally an approximate value for the non-strange current quark mass of m equal to 0,64 +- 1,11μ is extracted from the data

  13. Measurement of the pion form factor at higher energies

    Energy Technology Data Exchange (ETDEWEB)

    Mack, D.J. [CEBAF, Newport News, VA (United States)

    1994-04-01

    One of the strongest arguments for increasing the nominal CEBAF beam energy to equal or exceed 6 GeV is that one would be able to make quality high Q{sup 2} measurements of the charged pion form factor.

  14. On two-particle correlations of identical pions

    International Nuclear Information System (INIS)

    Podgoretskij, M.I.

    1991-01-01

    The pion generation processes, in which the interference term describing the correlations of identical pions seems to be negative, have been analyzed. It is shown that similar processes can take place, in particular, in nuclear collisions at intermediate energies

  15. Theory of the low-energy pion-nucleon interaction

    International Nuclear Information System (INIS)

    Banerjee, M.K.; Cammarata, J.B.

    1978-01-01

    A once-subtracted form of the Low equation for the pion-nucleon scattering amplitude is derived, with partial conservation of axial-vector current used to define the amplitude when one pion is off the mass shell. The static approximation is not made and both the seagull terms and the antinucleon contribution (z graphs) are retained. The theory is applied to calculate the S-wave amplitudes in the elastic scattering region. Good agreement is found with the phase shift fits to the data when we use vertical-barg/sub π/(4M 2 ) vertical-bar = 11.69 and 25.5 MeV for the πN sigma commutator. The implications of this work for the analysis of low-energy elastic scattering of pions form nuclei are discussed. In particular, we point out how this work establishes the presence of a Laplacian term in the pion-nucleus optical potential with a magnitude that is fixed from the value of the sigma commutator

  16. Single- and double-charge exchange at low pion energies

    International Nuclear Information System (INIS)

    Baer, H.W.

    1991-01-01

    A review is given of pion single- and double-charge exchange reactions at incident energies of 25 to 65 MeV leading to isobaric analog states, and in the case of double-charge exchange leading to the ground state of the residual nucleus. The crucial role of the higher nuclear transparency at low pion energies for the analysis of the data in terms of single and double scattering is demonstrated. The large effects on double-charge exchange produced by the spatial correlations in nuclear wave functions are evident. The data on 1f 7/2 nuclei at 35 MeV are used to establish the general validity of a shell-model-based two-amplitude model for these transitions. Recent measurements of the energy dependence between 25 and 65 MeV of double-charge exchange cross sections at forward angles are presented and discussed. 33 refs., 19 figs

  17. Low-energy pion double charge exchange and nucleon-nucleon correlations in nuclei

    International Nuclear Information System (INIS)

    Leitch, M.J.

    1989-01-01

    Recent measurements of pion double-charge exchange (DCX) at energies 20 to 70 MeV are providing a new means for studying nucleon-nucleon correlations in nuclei. At these energies the nucleus is relatively transparent, allowing simpler theoretical models to be used in interpreting the data and leading to a clearer picture. Also the contribution to DCX of sequential charge-exchange scattering through the intermediate analog state is suppressed near 50 MeV and transitions through non-analog intermediate states become very important. Recent theoretical studies by several groups have shown that while transitions through the analog route involve relatively long nucleon-nucleon distances, those through non-analog intermediate states obtain nearly half their strength from nucleon pairs with less than 1 fermi separation. Thus DCX near 50 MeV is an excellent way to study short-range nucleon-nucleon correlations. 31 refs., 29 figs., 4 tabs

  18. Inelastic pion scattering by 13C at low energies

    International Nuclear Information System (INIS)

    Mitchell, J.H.

    1987-03-01

    Angular distributions for inelastically scattered pions were obtained for several states in 13 C at an incident energy of 65 MeV. The data include results from both π + and π - measurements. In addition, π - measurements were made at T/sub π/ = 50 MeV at one angle to give a two point fixed-q excitation function. The data are compared to theory and the data of others. As might be expected, medium corrections are shown to be considerably more important at low energies than at resonance. This is true for inelastic transitions of multipolarity 0,2 and 3. Parameters derived from an analysis of elastic pion scattering and SCX data also provide an adequate description of the inelastic transitions. The charge asymmetry in the cross sections for the 9/2 + state that was seen at resonance persists at these energies. This result is consistent with an impulse approximation treatment of the spin-flip amplitude. This is true even though the incoming energy of the pions is far below the range where the validity of an impulse treatment is expected. 65 refs., 45 figs

  19. Future possibilities with intermediate-energy neutron beams

    International Nuclear Information System (INIS)

    Brady, F.P.

    1987-01-01

    Future possibilities for using neutrons of intermediate energies (50 - 200 MeV) as a probe of the nucleus are discussed. Some of the recent thinking concerning a systematic approach for studying elastic and inelastic scattering of electrons and hadrons and the important role of medium- and intermediate-energy neutrons in such a programme is reviewed. The advantages of neutrons in this energy range over neutrons with lower energies and over intermediate-energy pions for determining nuclear-transition and ground state densities, and for distinguishing proton from neutron density (isovector sensitivity), are noted. The important role of (n,p) charge exchange reactions in nuclear excitation studies is also reviewed. Experimental methods for utilizing neutrons as probes in elastic, inelastic, and charge exchange studies at these energies are discussed

  20. Intermediate energy nuclear fission

    International Nuclear Information System (INIS)

    Hylten, G.

    1982-01-01

    Nuclear fission has been investigated with the double-kinetic-energy method using silicon surface barrier detectors. Fragment energy correlation measurements have been made for U, Th and Bi with bremsstrahlung of 600 MeV maximum energy. Distributions of kinetic energy as a function of fragment mass are presented. The results are compared with earlier photofission data and in the case of bismuth, with calculations based on the liquid drop model. The binary fission process in U, Yb, Tb, Ce, La, Sb, Ag and Y induced by 600 MeV protons has been investigated yielding fission cross sections, fragment kinetic energies, angular correlations and mass distributions. Fission-spallation competition calculations are used to deduce values of macroscopic fission barrier heights and nuclear level density parameter values at deformations corresponding to the saddle point shapes. We find macroscopic fission barriers lower than those predicted by macroscopic theories. No indication is found of the Businaro Gallone limit expected to occur somewhere in the mass range A = 100 to A = 140. For Ce and La asymmetric mass distributions similar to those in the actinide region are found. A method is described for the analysis of angular correlations between complementary fission products. The description is mainly concerned with fission induced by medium-energy protons but is applicable also to other projectiles and energies. It is shown that the momentum and excitation energy distributions of cascade residuals leading to fission can be extracted. (Author)

  1. Partial inelasticity coefficients of negative pions produced in hadron-nucleus and nucleus-nucleus collisions at high energies

    International Nuclear Information System (INIS)

    OLIMOV, K.; LUTPULLAEV, S.L.; PETROV, V.I.; OLIMOV, A.K.

    2015-01-01

    New experimental data on the partial inelasticity coefficients of negative pions produced in "1"6Op-collisions at 3.25 A GeV/s, pC-interactions at 4.2 and 9.9 GeV/s, and d,α,C(C)-collisions at 4.2 A GeV/s are presented. It is established that the behavior of partial inelasticity coefficients of pions at intermediate energies (<10 GeV) in hadron-nucleus collisions has a transitional character, reaching the limiting value at ultrahigh energies. It is shown that the mean values of partial inelasticity coefficients of pions produced in nucleus-nucleus collisions decrease with an increase in mass number of the projectile nucleus. (authors)

  2. Pion nucleon interaction at low energy

    International Nuclear Information System (INIS)

    Banerjee, M.K.

    1979-03-01

    A theory of the πN interaction at low energy is described. An analogy is made with an unusual approach to potential scattering theory. Phase shifts, cross sections, and scattering amplitudes and lengths are calculated. 28 references

  3. Scattering of low-energy pions by p-shell nuclei

    International Nuclear Information System (INIS)

    Khankhasaev, M.Kh.

    1987-01-01

    Low-energy pion-carbon scattering (up to 50 MeV) is analysed in the framework of the unitary approach based on the method of evolution in the coupling constant. It is shown that at pion energy ∼ 50 MeV the differential cross section arises as a result of the strong interference between the pure potential scattering and absorption channels. In this energy region the scattering data are very sensitive to the dynamics of the pion-nucleus interaction

  4. High yield of low-energy pions from a high-energy primary proton beam

    International Nuclear Information System (INIS)

    Bertin, A.; Capponi, S.; De Castro, S.

    1987-01-01

    This paper presents the results of the first measurement on the yield of pions with momentum smaller than 220 MeV/c, produced by a 300 GeV/c proton beam. The measurements, performed at the CERN super proton synchrotron using tungsten production targets of different lengths, are discussed referring to the possibility of extending to high-energy laboratories the access to fundamental research involving low-energy pions and muons

  5. Virtual photons in the pion form factors and the energy-momentum tensor

    Energy Technology Data Exchange (ETDEWEB)

    Kubis, Bastian E-mail: b.kubis@fz-juelich.de; Meissner, Ulf-G. E-mail: ulf-g.meissner@fz-juelich.de

    2000-05-22

    We evaluate the vector and scalar form factor of the pion in the presence of virtual photons at next-to-leading order in two-flavor chiral perturbation theory. We also consider the scalar and tensor pion form factors of the energy-momentum tensor. We find that the intrinsic electromagnetic corrections are very small for the vector as well as the charged pion scalar form factor. The scalar radius of the neutral pion is reduced by two percent. We perform infrared regularization by considering electron-positron annihilation into pions and the decay of a light Higgs boson into a pion pair. We discuss the detector resolution dependent contributions to the various form factors and pion radii.

  6. Virtual photons in the pion form factors and the energy-momentum tensor

    International Nuclear Information System (INIS)

    Kubis, Bastian; Meissner, Ulf-G.

    2000-01-01

    We evaluate the vector and scalar form factor of the pion in the presence of virtual photons at next-to-leading order in two-flavor chiral perturbation theory. We also consider the scalar and tensor pion form factors of the energy-momentum tensor. We find that the intrinsic electromagnetic corrections are very small for the vector as well as the charged pion scalar form factor. The scalar radius of the neutral pion is reduced by two percent. We perform infrared regularization by considering electron-positron annihilation into pions and the decay of a light Higgs boson into a pion pair. We discuss the detector resolution dependent contributions to the various form factors and pion radii

  7. Isotensor electromagnetic current in low energy pion photoproduction

    International Nuclear Information System (INIS)

    Aznauryan, I.G.; Nagorskaya, I.A.; Zaslavskij, A.N.

    1974-01-01

    Recent experimental data on single pion photoproduction in the Δ (1236) resonance region are discussed. The role of the high energy contributions into the dispersion integrals are analyzed. Estimates for the magnitude of the isotensor contributions are obtained in the dispersion approach using the experimental data of various groups. In spite of the great number of the experiments the estimate is ambiguous yet since there are direct discrepancies between the data of various groups, besides, certain available data are incomplete. The data of some groups are compatible with 10% isotensor contribution

  8. Theoretical contributions to coherent pion production in subthreshold and relativistic heavy-ion collisions

    International Nuclear Information System (INIS)

    Deutchman, P.A.; Norbury, J.W.; Townsend, L.W.

    1986-01-01

    The analysis results from a microscopic calculation for pion production in heavy-ion collisions at intermediate to relativistic energies both above and below pion threshold are presented and the most important terms that contribute to the pion spectrum are determined. The energy dependence and the effects on the pion spectrum due to the various parameters in the theory are examined. The model is applied to coherent pion-production in 16 O + 12 C collisions. (orig.)

  9. Review of recent experiments in intermediate energy nuclear physics

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P D [Carnegie-Mellon Univ., Pittsburgh, PA (USA)

    1978-01-01

    The data generated at intermediate-energy accelerator facilities has expanded rapidly over the past few years. A number of recent experiments chosen for their impact on nuclear structure questions are reviewed. Proton scattering together with pionic and muonic atom X-ray measurements are shown to be giving very precise determinations of gross nuclear properties. Pion scattering and reaction data although less precise, are starting to generate a new understanding of wave functions of specific nuclear states. Specific examples where new unpublished data are now available are emphasized. In addition, other medium-energy experiments that are starting to contribute to nuclear structure physics are summarized.

  10. Large-angle theory for pion-nucleus scattering at high energies

    International Nuclear Information System (INIS)

    Hoock, D.W. Jr.

    1978-01-01

    An approximate solution for high-energy, projectile-nucleus, multiple scattering is developed from the exact Watson series and applied to pion scattering for 12 C and 4 He. Agreement with measured differential cross sections available from the literature for the range 150 to 260 MeV pion laboratory energies is surprisingly good. The approximation method expands the propagators of the Watson series about the transverse component of the momentum transfer. Contributions of each of the first two terms to double scattering from a Gaussian potential are compared to the exact solution. The purely plane-wave propagation produces a scattering amplitude that agrees to order (k 0 a) -1 with the exact solution at the forward and backward directions at high energies. The second (off-axis) propagation term produces an amplitude that is one order smaller at forward angles and two orders smaller at 180 0 than the exact amplitude. At intermediate angles it is of the same order. The general multiple-scattering series is approximated with selection of plane-wave propagation as the fundamental process at large and small angles. This model suggests that a single nucleon accepts most of the momentum transfer for backward scattering. The resulting multiple-scattering formula agrees with the well-known high-energy eikonal theory at small angles and the backward-angle scattering formula of Chen at exactly 180 0 . A lowest-order formula that includes off-axis propagation is also derived. Predicted differential cross sections are found to be sensitive to nucleon motion and binding. For 4 He the effect of the nuclear potential on the pion kinetic energy is also examined and found to produce significant changes in the predicted cross sections

  11. Theoretical research in intermediate-energy nuclear physics

    International Nuclear Information System (INIS)

    Seki, R.

    1991-01-01

    This report discusses progress that has been made on the following six problems: (1) final state interactions in (e,e'p) at high momentum transfer; (2) a numerical calculation of skyrmion-antiskyrmion annihilation; (3) pion-nucleus interactions above 0.5 GeV/c; (4) pionic atom anomaly; (5) baryon interactions in Skyrme model; and (6) large N c quantum hydrodynamics. The problems deal with various topics in intermediate-energy nuclear physics. Since we plan to continue the investigation of these problems in the third year, we describe the plan of the investigation together

  12. Tensor polarized deuteron targets for intermediate energy physics experiments

    International Nuclear Information System (INIS)

    Meyer, W.; Schilling, E.

    1985-03-01

    At intermediate energies measurements from a tensor polarized deuteron target are being prepared for the following reactions: the photodisintegration of the deuteron, the elastic pion-deuteron scattering and the elastic electron-deuteron scattering. The experimental situation of the polarization experiments for these reactions is briefly discussed in section 2. In section 3 the definitions of the deuteron polarization and the possibilities to determine the vector and tensor polarization are given. Present tensor polarization values and further improvements in this field are reported in section 4. (orig.)

  13. Possibility of investigation of pion degrees of freedom in atomic nuclei with the help of quasielastic pions knocking out by high energy electrons

    CERN Document Server

    Neudachin, V G; Sviridova, L L

    2002-01-01

    The attention is paid to the interesting possibilities of studying the pion degrees of freedom in the atomic nuclei by means of the quasielastic knocking out of pion (e, ep) from the nuclei by the electrons with the energy of several GeV. It appears, that the pulse distribution of the pions, knocked out from the separate nucleons and the nuclei, is in the whole differ essentially different

  14. Galileo-invariant theory of low energy pion-nucleus scattering

    International Nuclear Information System (INIS)

    Mach, R.

    1980-01-01

    Two classes of Galileo-invariant optical models are constructed for pion elastic scattering by nuclei. The first, the two-body model, has been obtained assuming that the pion-bound nucleon dynamics is determined by the pion-nucleon kinetic energy. In deriving the second model, the (A+1)-body dynamics has been taken into account. The technique of effective nucleon momenta maintains the nonlocal propagation of the pion-target nucleon subsystem through the nucleus in contrast with the standard static approximation

  15. Galileo-invariant theory of low energy pion-nucleus scattering. II

    International Nuclear Information System (INIS)

    Mach, R.

    1983-01-01

    Two classes of Galileo-invariant optical models are constructed for pion elastic scattering by nuclei. The former, the two-body model, was obtained assuming that the pion-bound nucleon dynamics is determined by the pion-nucleon kinetic energy. In deriving the latter model, the (A+1)-body dynamics was taken into account. The technique of effective nucleon momenta maintains the nonlocal propagation of the pion-target nucleon subsystem through the nucleus in contrast with the standard static approximation. (author)

  16. Nuclear structure at intermediate energies

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1989-01-01

    This paper discusses the following topics: Σdegree C Spin Transfer Experiment; Strangeness Production in Heavy Ion Collisions; Search for a J PC Exotic Hybrid Meson; Antiproton-Nucleus Interactions; Single Pion Production in np Scattering; Two-and Three-Spin Measurements in pp-pp; Proton-Deuteron Elastic Scattering at 800 MeV Two- and Three-Spin Observables; pp Elastic Absolute Cross-Section Measurements; Single Pion Production in np Scattering; Photojets from Nuclei; CCD Development; Computer Acquisition and Computer Software

  17. Nuclear structure at intermediate energies

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1990-01-01

    This paper discusses the following topics: antiproton nucleus interactions; strangeness production in heavy ion collisions; search for a J PC exotic hybrid meson; the SMC experiment; pion production in rvec np scattering; spin transfer measurements for rvec np elastic scattering; pion production in rvec n rvec p scattering; radiative muon capture (RMC) on hydrogen; radiative decays of low-lying hyperons; photoproduction of jets in nuclei; cylindrical multiplicity detector; MWPC detectors and electronics; lead glass array; cylindrical wire chamber; beam calorimeter; shower counter; and muon veto hodoscope

  18. Workshop on hadron structure from photo-reactions at intermediate energies: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Nathan, A.M.; Sandorfi, A.M. (eds.)

    1992-01-01

    This report contains papers on the following topics: The proton compton effect: Recent measurements of the electric and magnetic polorizabilities of the proton; experiments on the electric polarizability of the neutron; chiral symmetry and nucleon polarizabilities; chiral model predictions for electromagnetic polarizabilities of the nucleon, a consumer report; the polarizabilities of bound nucleons; nucleon polarizability in free space and in nuclear matter; mechanisms of photon scattering on nucleons at intermediate energies; pion polarizabilities in chiral perturbation theory; pion polarizabilities and the shielding of [sigma](700)-meson exchange in [gamma][gamma][yields][pi][pi] processes; pion and kaon polarizabilities in the quark confinement model; radiative pion photoproduction and pion polarizabilities; pion and sigma polarizabilities and radiative transitions; the quadrupole amplitude in the [gamma][Nu]-[Delta] transition; pion photoproduction and the [gamma][Nu]-[Delta] amplitudes; effective- lagrangians, Watson's theorem, and the E2/M1 mixing ratio in the excitation of the delta resonance; new measurements of the p([rvec [gamma

  19. Photonuclear reactions at intermediate energy

    International Nuclear Information System (INIS)

    Koch, J.H.

    1982-01-01

    The dominant feature of photonuclear reactions at intermediate energies is the excitation of the δ resonance and one can therefore use such reactions to study the dynamics of δ propagation in a nucleus. Following an introductory section the author comments on photoabsorption on a single nucleon in Section II. A review of the δ-n Greens function and of the photonuclear amplitude is given in Section III. Results for photoabsorption on 4 He are shown in Section IV and compared with the data. Coherent π 0 photoproduction is discussed in Section V and calculations for 12 C are compared to recent measurements. (Auth.)

  20. Pion production in high energy heavy ion collisions

    International Nuclear Information System (INIS)

    Wolf, K.L.; Bock, R.; Brockmann, R.

    1984-01-01

    Experimental data for heavy ion pion production reactions are compared with the predictions of a number of versions of cascade models. Pion suppression effects observed in the experimental data are fit by introducing refinements into cascade theory. Impact parameter adjustment, off-shell effects on the potential and perturbations due to nuclear matter are considered

  1. A few aspects of intermediate energy heavy ion reactions

    International Nuclear Information System (INIS)

    Guet, C.

    1982-10-01

    Some aspects of reactions induced by intermediate energy heavy ions, with a special emphasis of 85 MeV/nucleon 12 C data, are discussed and compared to low energy and relativistic energy features. Transition from mean field to independant nucleon picture is advocated by an increase of nuclear transparency illuminated by reaction cross section estimations. Projectile-like fragment distributions, while demonstrating a typical high energy fragmentation behaviour, exhibit low energy regime distortions. Light fragments, associated to large parallel momentum transfer may result from total explosion. Proton emission is investigated and discussed in terms of opposite models such as thermal equilibrium and nucleon-nucleon scattering. First pion production data are well explained by single nucleon-nucleon inelastic scattering

  2. Spin physics at intermediate energies

    International Nuclear Information System (INIS)

    Burkert, V.

    1986-01-01

    In this session a total of 25 contributed papers were presented studying a broad range of spin effects in nucleons and nuclei using electromagnetic (electrons and photons) and hadronic (pions and nucleons) probes. The status of the theory was characterized by its almost total absence. Only one theoretical contribution was presented at this session. Those experiments examining electromagnetic-, electroweak- and weak-strong interactions were emphasized

  3. Production of charged pions in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Bernard, V.; Girard, J.; Julien, J.

    1983-03-01

    Cross-sections for the production of π + and π - have been measured over a wide range of angles for 12 C + 7 Li, 12 C + 12 C and 12 C + 208 Po collisions at 60A, 75A and 85A MeV. Spectral shapes and absolute yields are reproduced reasonably well by nucleon-nucleon scattering calculations, assuming interacting soft momentum spheres. The apparent velocity of the system in which the π + emission is symmetric is closer to the nucleus-nucleus c.m. velocity than to the mean speed system. The Coulomb corrected π - /π + ratio is close to unity for 12 C + 12 C. The corresponding ratio for 12 C + 208 Pb is however much larger than expected only from the neutron excess in 208 Pb. (Authors)

  4. Pion-pion interactions in particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Martin, B R; Morgan, D; Shaw, G

    1976-01-01

    The aim of the book is to review the experimental and theoretical work on the processes involving pion-pion interactions. Sources of information on pion-pion scattering are examined, including pion production, dipion exchange, and weak and electromagnetic interactions. The theory and models of pion-pion scattering are discussed with reference to fixed momentum transfer, partial wave amplitudes, models and phenomenology, dynamical and field theoretic models, finite-energy sum rules, duality and the Veneziano model, resonance spectra and lastly, predictions from current algebra.

  5. Effect of pion external distortion on low energy pion double-charge-exchange

    International Nuclear Information System (INIS)

    Khankhasaev, M.Kh.; Kurmanov, Zh.B.; Johnson, M.B.

    1993-01-01

    The effects of the external pion distortion for iso-elastic charge exchange scattering (within the framework of the isospin invariant optical model) is considered. An approximated method of taking into account the distortion based on the separable expansion of the optical potential in momentum space is developed. The result of external distortions for sequential scattering 14 C(π + , π - ) 14 O at 50 MeV is presented. It is shown that this distortion gives a small enhancement to forward and reduced the differential cross sections at large angels. 22 refs., 5 figs., 1 tab

  6. Parameterization of pion production and reaction cross sections at LAMPF energies

    International Nuclear Information System (INIS)

    Burman, R.L.; Smith, E.S.

    1989-05-01

    A parameterization of pion production and reaction cross sections is developed for eventual use in modeling neutrino production by protons in a beam stop. Emphasis is placed upon smooth parameterizations for proton energies up to 800 MeV, for all pion energies and angles, and for a wide range of materials. The resulting representations of the data are well-behaved and can be used for extrapolation to regions where there are no measurements. 22 refs., 16 figs., 2 tabs

  7. Photoproduction of pions on low-energy protons

    International Nuclear Information System (INIS)

    Grushin, V.F.

    1989-01-01

    This paper reports that a study is made of the complete experiment problem and photoproduction of pions on protons. The problem of the volume and content of a complete experiment is solved in the area of photon energies up to 500 MeV for the channels γp-π + n and γp-π → π 0 p. Experimental data assuring a complete experiment are used for multipole analysis of the channels γp → π + n, π 0 p and the real and imaginary parts of s- and p-wave multipole amplitudes are obtained. Estimates are produced for the pole parameters (mass and width) of the Δ + 33 isobar. An electrical quadrupole amplitude of the transition γp → Δ + 33 was found which is significantly different form zero, indicating the existence of a tensor interaction between quarks in hadrons. Data on photoproduction on mesons are used to extract quantitative estimates of the vector and tensor constants of interaction of an ω meson with nucleons

  8. Electron-atom scattering at intermediate energies

    International Nuclear Information System (INIS)

    Kingston, A.E.; Walters, H.R.J.

    1982-01-01

    The problems of intermediate energy scattering are approached from the low and high energy ends. At low intermediate energies difficulties associated with the use of pseudostates and correlation terms are discussed, special consideration being given to nonphysical pseudoresonances. Perturbation methods appropriate to high intermediate energies are described and attempts to extend these high energy approximations down to low intermediate energies are studied. It is shown how the importance of electron exchange effects develops with decreasing energy. The problem of assessing the 'effective completeness' of pseudostate sets at intermediate energies is mentioned and an instructive analysis of a 2p pseudostate approximation to elastic e - -H scattering is given. It is suggested that at low energies the Pauli Exclusion Principle can act to hide short range defects in pseudostate approximations. (author)

  9. Neutral pion production in heavy ion collisions at SIS-energies

    International Nuclear Information System (INIS)

    Sumbera, M.; Loehner, H.; Raschke, A.E.; Venema, L.B.; Wilschut, H.W.

    1993-01-01

    The production of π 0 mesons has been studied in the reactions 40 Ar+Ca and 197 Au+Au at 1.0 GeV/u. While the pion transverse momentum spectrum from the reaction Ar+Ca is consistent with a simple thermal exponential slope a second component is seen for the system Au+Au. Both neutral pions, neutrons and charged particles exhibit an anisotropy in the reaction plane azimuth. At midrapidity the emission of pions perpendicular to the reaction plane increases with their energy. (orig.)

  10. Pion production differential cross section of heavy-ion collisions at subthreshold energies

    International Nuclear Information System (INIS)

    Abumurad, K.M.

    1987-01-01

    A revised model for pion production in heavy-ion peripheral collisions at subthreshold energies is presented. The pion-production mechanism investigated here is a two step process involving the formation and subsequent decay of an isobar resonance in the projectile nucleus. The independent-particle shell model with harmonic oscillator states is used to approximate the internal structure of the nucleus. The pion production cross section shows a definite angular distribution characteristic of coherent production. It also gives an indication of the quantum signature of the emitted pions. The results show the disappearance of the quantum signature from the energy spectra because of the inclusion of higher order multipoles. The theory is compared to recent experimental data. The comparison reveals that the general trend is reproduced, which is encouraging

  11. Energy cost of negative pion production on deuterium-tritium target

    Energy Technology Data Exchange (ETDEWEB)

    Kuzminov, V.V. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation)); Petrov, Yu.V. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation)); Shabelski, Yu.M. (Petersburg Nuclear Physics Inst., Gatchina, St. Petersburg (Russian Federation))

    1993-12-01

    The negative pion production by deuterons (T[sub 0] = 0.8 GeV/nucl.) was calculated for a cylindrical gaseous deuterium-tritium target (the density of DT-mixture is [phi] = 0.5). Revised cross sections of nucleon-nucleus interaction were used in a Monte Carlo simulation and multiple nucleon-nuclei collisions were taken into account. The energy cost of negative pion production is [epsilon][sub [pi][sup -

  12. Probing nuclear correlations with pion-nucleus double charge exchange

    International Nuclear Information System (INIS)

    Ginocchio, J.N.

    1988-01-01

    In this paper we have calculated the lowest order pion double charge reaction mechanism using shell model wavefunctions of medium weight nuclei. We have the sequential reaction mechanism in which the pion undergoes two single-charge exchange scatterings on the valence neutrons. The distortion of the incoming, intermediate, and outgoing pion are included. The closure approximation is made for the intermediate states with an average excitation energy used in the pion propagator. The double-charge exchange is assumed to take place on the valence nucleons which are assumed to be in one spherical shell model orbital. 34 refs., 5 figs., 3 tabs

  13. Kaon production in intermediate-energy nuclear collisions

    International Nuclear Information System (INIS)

    Russkikh, V.N.; Ivanov, Yu.B.

    1992-01-01

    Production of positive kaons in nuclear collisions at intermediate energies (∝ 1-2 GeV/nucleon) is studied within the 3-dimensional fluid dynamics combined with the hadrochemical kinetics for strangeness production. Sensitivity of the kaon probe to a form of the nuclear equation of state is analyzed. The model reproduces total and differential cross sections of Ne+NaF→K + +X and Ne+Pb→K + +X reactions at E lab =2.1 GeV/nucleon, provided a soft equation of state is used. The pion-production data are also well described employing the same equation of state. Predictions are made for the current experiment on kaon production at the SIS accelerator. The obtained results are compared with the predictions of other models. (orig.)

  14. The low-energy theorem of pion photoproduction using the Skyrme model

    International Nuclear Information System (INIS)

    Ikehashi, T.; Ohta, K.

    1995-01-01

    We reassess the validity of the current-algebra based low-energy theorem of pion photoproduction on the nucleon using the Skyrme model. We find that one of the off-shell electromagnetic form factors of the nucleon exhibits infrared divergence in the chiral limit. This contribution introduces an additional term to the threshold amplitude predicted by the low-energy theorem. The emergence of the additional term indicates an unavoidable necessity of off-shell form factors in deriving the low-energy theorem. In the case of neutral pion production, the new contribution to the threshold amplitude is found to be comparable in magnitude to the low-energy theorem's prediction and has the opposite sign. In the charged pion production channels, the correction to the theorem is shown to be relatively small. (orig.)

  15. Nuclear structure at intermediate energies: Progress report, January 1-December 31, 1988

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1988-01-01

    This report discusses the progress in the following experiments: Λ Spin Transfer Experiment; Σ 0 Spin Transfer Experiment; Strangeness Production in Heavy Ion Collisions; Measurement of the Imaginary Part of the I=1 /bar N/N S-Wave Scattering Length; Single Pion Production in np Scattering; Measurements of the π + d→Δ ++ n at Intermediate Energy; and PhotoJets from Nuclei

  16. Nuclear energy density functional from chiral pion-nucleon dynamics revisited

    Science.gov (United States)

    Kaiser, N.; Weise, W.

    2010-05-01

    We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from 1 π-exchange, iterated 1 π-exchange, and irreducible 2 π-exchange with intermediate Δ-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass M(ρ) entering the energy density functional is identical to the one of Fermi-liquid theory when employing the improved density-matrix expansion. The strength F(ρ) of the ( surface-term as provided by the pion-exchange dynamics is in good agreement with that of phenomenological Skyrme forces in the density region ρ/2short-range spin-orbit interaction. The strength function F(ρ) multiplying the square of the spin-orbit density comes out much larger than in phenomenological Skyrme forces and it has a pronounced density dependence.

  17. (p,n) reaction at intermediate energy

    International Nuclear Information System (INIS)

    Goodman, C.D.

    1979-01-01

    The use of the (p,n) reaction in exploring effective interactions is reviewed. Some recent data on self-conjugate nuclei taken at the Indiana University Cyclotron Facility (IUCF) are presented, and the differences between low- and high-energy data are emphasized. Experimental problems and techniques used are briefly described. It is concluded that forward-angle (p,n) spectra at energies greater than 100 MeV are dominated by Gamow-Teller (GT) transitions, while Fermi transitions (IAS transitions) dominate near 45 MeV. Prominent GT transitions are expected from a pion-exchange interaction, and it is expected that OPEP is the dominant component of the interaction in the energy range of 100 to 200 MeV. 27 figures, 2 tables

  18. Subthreshold pion production study with heavy ions at low and medium energy

    International Nuclear Information System (INIS)

    Rebreyend, D.

    1988-02-01

    In the domain of subthreshold pion production with heavy ions at low and medium energy (40-100 MeV/u), only Π 0 have been up to now, extensively studied. The incompleteness of the charged pion data and especially the lack of results for pions of energy less than 30 MeV have led to conceive the magnetic spectrometer SPIC. In the present work, we demonstrate that this spectrometer is particularly well suited for the detection of low energy charged pions (Inferior threshold of detection: T Π = 7 MeV), emitted around 0 0 in heavy ion collisions. Principle and performances, successfully tested at 38 and 93 MeV/u, are described in detail. The main characteristics of a Π 0 spectrometer, that was used to realize a comparative experiment of Π 0 production, are then given. The last chapter is devoted to experimental results. First, we present the results obtained with the 16 0 beam of 38 MeV/u of the SARA accelerator, in charged pions (Al and Ni targets) and in Π 0 (Al and Au targets). A comparison of the data Π - /Π 0 seems to indicate that coulomb effects are surprisingly small. Finally, we report the data obtained with the 16 0 beam of 93 MeV/u of GANIL. In contrast with low energy data, coulomb effects are very strong (ratio Π - /Π + = 100 for pions of low energy with heavy targets) and allowed us to extract informations on the geometry of the collision [fr

  19. Nuclear studies with intermediate energy probes

    International Nuclear Information System (INIS)

    Norum, B.E.

    1992-01-01

    Data from measurements at NIKHEF-K of the electro-production of neutral pions from the proton were completely analyzed and axe about to be submitted for publication. These results represent the first precise measurement of this fundamental process in the threshold region. The results are completely consistent with calculations based upon the Low Energy Theorems. Results from studies of a gas jet target in the electron storage ring of the Saskatchewan Accelerator Laboratory (SAL) have been fully analyzed and are being prepared for publication. An Internal Target Development Facility (ITDF), established at NIKHEF-K in a collaborative effort for the purpose of developing higher density gas jet targets suitable for use in electron rings, is operational. Diagnostic techniques are being evaluated in preparation for evaluating jet technology options. Our study of the calcium isotopes ( 42 C and 44 C) is nearing completion. Both the electron and proton scattering data have been completely analyzed. Consistent proton and neutron transition densities have been extracted, and are being compared to corresponding results from pion scattering. Preparations for (γ,π - ) measurements at SAL have been completed, and data taking is about to commence

  20. Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    Vary, J.P.

    1992-01-01

    Progress during the last year is reviewed under the following topics: relativistic hadron--nucleus and nucleus--nucleus collisions (heavy meson production, photon production and fragmentation functions--direct photon production with the QCM and photon fragmentation functions, Cronin efffect and multiple scattering, effective nuclear parton distributions); solving quantum field theories in nonperturbative regime; light-front dynamics and high-spin states (soft form factor of the pion and nucleon for transverse and longitudinal momentum transfers, light front spinors for high-spin objects); high-energy spin physics; relativistic wave equations, quarkonia, and e + e - resonances; associated production of Higgs boson at collider energies, and microscopic nuclear many-body theory and reactions. 135 refs

  1. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    International Nuclear Information System (INIS)

    Abat, E; Arik, E; Abdallah, J M; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T P A; Aleksa, M; Anghinolfi, F; Baron, S; Alexa, C; Anderson, K; Andreazza, A; Banfi, D; Antonaki, A; Arabidze, G; Atkinson, T; Baines, J; Baker, O K

    2011-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  2. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    Energy Technology Data Exchange (ETDEWEB)

    Abat, E; Arik, E [Bogazici University, Faculty of Sciences, Department of Physics, TR - 80815 Bebek-Istanbul (Turkey); Abdallah, J M [Institut de Fisica d' Altes Energies, IFAE, Universitat Autonoma de Barcelona, Edifici Cn, ES - 08193 Bellaterra (Barcelona) Spain (Spain); Addy, T N [Hampton University, Department of Physics, Hampton, VA 23668 (United States); Adragna, P [Queen Mary, University of London, Mile End Road, E1 4NS, London (United Kingdom); Aharrouche, M [Universitaet Mainz, Institut fuer Physik, Staudinger Weg 7, DE 55099 (Germany); Ahmad, A [Insitute of Physics, Academia Sinica, TW - Taipei 11529, Taiwan (China); Akesson, T P A [Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Box 118, SE - 221 00, Lund (Sweden); Aleksa, M; Anghinolfi, F; Baron, S [European Laboratory for Particle Physics CERN, CH-1211 Geneva 23 (Switzerland); Alexa, C [National Institute of Physics and Nuclear Engineering (Bucharest -IFIN-HH), P.O. Box MG-6, R-077125 Bucharest (Romania); Anderson, K [University of Chicago, Enrico Fermi Institute, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Andreazza, A; Banfi, D [INFN Sezione di Milano, via Celoria 16, IT - 20133 Milano (Italy); Antonaki, A; Arabidze, G [University of Athens, Nuclear and Particle Physics Department of Physics, Panepistimiopouli Zografou, GR 15771 Athens (Greece); Atkinson, T [School of Physics, University of Melbourne, AU - Parkvill, Victoria 3010 (Australia); Baines, J [Rutherford Appleton Laboratory, Science and Technology Facilities Council, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom); Baker, O K, E-mail: kjg@particle.kth.se [Yale University, Department of Physics , PO Box 208121, New Haven, CT06520-8121 (United States)

    2011-06-15

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  3. Can pions created in high-energy heavy-ion collisions produce a Centauro-type effect?

    International Nuclear Information System (INIS)

    Martinis, M.; Mikuta-Martinis, V.; Crnugelj, J.

    1995-01-01

    We study a Centauro-type phenomenon in high-energy heavy-ion collisions by assuming that pions are produced semiclassically both directly and in pairs through the isovector channel. The leading-particle effect and the factorization property of the scattering amplitude in the impact-parameter space are used to define the classical pion field. We show that the Centauro-type effect is strongly suppressed if a large number of pions are produced in isovector pairs. Our conclusion is supported through the calculation of two pion correlation parameters, f 2 0- and f 2 00 , as well as f 2, n - 0 and the average number of neutral pions (left-angle n 0 right-angle n- ) a a function of negative pions (n - ) produced

  4. Pion production - a probe for coherence in medium energy heavy ion collisions

    International Nuclear Information System (INIS)

    Stachel, J.

    1985-01-01

    Neutral pion production is observed in heavy ion collisions at beam energies as low as 25 MeV/u, where this process is consumming the major portion of the total center of mass energy available. At these low beam energies single nucleon nucleon collision models and also models that incorporate the cooperative sharing of the beam energy of several nucleons do not reproduce the data. Rather, the data presented here call for a fully coherent production mechanism. (orig.)

  5. Proton scattering at intermediate energies

    International Nuclear Information System (INIS)

    Chaumeaux, A.; Layly, V.; Schaeffer, R.

    1977-01-01

    This article is devoted to the analysis of the most recent Saclay data of elastic and inelastic proton scattering on nuclei at incident energies around 1GeV ( 16 O, the Ca isotopes, the Ni isotopes, 90 Zr and 208 Pb). Various theories (Impulse or Glauber approximation) are comapred. It is shown that the reaction mechanism is very well understood at 1GeV and that, at these energies, absorption and distortion is small enough, so one can extract nuclear densities from the experiment. In particular, the shape of the neutron densities is given, and compared to the Hartree-Fock predictions. The uncertainties, especially in the determination of the neutron radii are discussed [fr

  6. Nuclear photoreactions at intermediate energies

    International Nuclear Information System (INIS)

    Christillin, P.

    1989-02-01

    We review the interaction of real photons with nuclei up to the GeV region. The common microscopic description of exchange effects below threshold and of the corresponding real photoproduction above, is emphasized. The theoretical problems connected with π photoproduction in Δ region and vector meson photoproduction are spelled out and solved. The gross features of the reaction mechanism are shown to explain both the low energy region, the bulk properties around the Δ resonance as well as the appearance of shadowing only above ρ threshold

  7. Reaction mechanism and nuclear correlations study by low energy pion double charge exchange

    International Nuclear Information System (INIS)

    Weinfeld, Z.

    1993-06-01

    In pion double-charge-exchange (DCX) reactions, a positive (negative) pion is incident on a nucleus and a negative (positive) pion emerges. These reactions are of fundamental interest since the process must involve at least two nucleons in order to conserve charge. Although two nucleon processes are present in many reactions they are usually masked by the dominant single nucleon processes. DCX is unique in that respect since it is a two nucleon process in lowest order and thus may be sensitive to two-nucleon correlations. Measurements of low energy pion double-charge-exchange reactions to the double-isobaric-analog-state (DIAS) and ground-state (GS) of the residual nucleus provide new means for studying nucleon-nucleon correlations in nuclei. At low energies (T π 7/2 shell at energies ranging from 25 to 65 MeV. Cross sections were measured on 42,44,48 Ca, 46,50 Ti and 54 Fe. The calcium isotopes make a good set of nuclei on which to study the effects of correlations in DCX reactions

  8. Chiral symmetry and low energy pion-nucleon scattering

    International Nuclear Information System (INIS)

    Coon, S.A.

    1999-01-01

    In these lectures, I examine the effect of the meson factory πN data on the current algebra/PCAC program which describes chiral symmetry breaking in this system. After historical remarks on the current algebra/PCAC versus chiral Lagrangians approaches to chiral symmetry, and description of the need for πN amplitudes with virtual (off-mass-shell) pions in nuclear force models and other nuclear physics problems, I begin with kinematics and isospin aspects of the invariant amplitudes. A detailed introduction to the hadronic vector and axial-vector currents and the hypothesis of partially conserved axial-vector currents (PCAC) follows. I review and test against contemporary data the PCAC predictions of the Goldberger-Treiman relation, and the Adler consistency condition for a πN amplitude. Then comes a detailed description of the current algebra Ward-Takahashi identities in the chiral limit and a brief account of the on-shell current algebra Ward-Takahashi identities. The latter identities form the basis of so-called current algebra models of πN scattering. I then test these models against the contemporary empirical πN amplitudes extrapolated into the subthreshold region via dispersion relations. The scale and the t dependence of the 'sigma term' is determined by the recent data. (author)

  9. Influence of the nuclear symmetry energy on the collective flows of charged pions

    Science.gov (United States)

    Gao, Yuan; Yong, Gao-Chan; Zhang, Lei; Zuo, Wei

    2018-01-01

    Based on the isospin-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) transport model, we studied charged pion transverse and elliptic flows in semicentral 197Au+197Au collisions at 600 MeV/nucleon. It is found that π+-π- differential transverse flow and the difference of π+ and π- transverse flows almost show no effects of the symmetry energy. Their corresponding elliptic flows are largely affected by the symmetry energy, especially at high transverse momenta. The isospin-dependent pion elliptic flow at high transverse momenta thus provides a promising way to probe the high-density behavior of the symmetry energy in heavy-ion collisions at the Facility for Antiproton and Ion Research (FAIR) at GSI, Darmstadt or at the Cooling Storage Ring (CSR) at HIRFL, Lanzhou.

  10. Intermediate-energy nuclear theory. Progress report, July 1, 1977--June 30, 1978

    International Nuclear Information System (INIS)

    Bryan, R.A.

    1978-03-01

    The research reported has centered on the nucleon-nucleon interaction at medium energies, with especial emphasis on the reaction NN → NNπ up to 800 MeV. Elastic NN scattering near the pion production threshold was also investigated, both through phase-shift analysis of data and theoretical interpretation of the intermediate-range force. The quasi-elastic amplitude N anti N → ππ for 4m/sub pi/ 2 less than or equal to t less than or equal to 50m/sub pi/ 2 was studied because of its bearing on the NN problem; a simple but useful model was developed. Finally, work on the pion-photoproduction reaction γN → πΔ was completed, and the close correspondence with the amplitude NN → NNπ exploited. A list of publications is included

  11. Rho meson self-energy and dielectron emissivity in an isospin-asymmetric pion medium

    International Nuclear Information System (INIS)

    Gulamov, T.I.; Titov, A.I.; Forschungszentrum Rossendorf e.V.; Kaempfer, B.; Technische Univ., Dresden

    1995-06-01

    The ρ meson self-energy in an isospin asymmetric pion gas at finite temperature and charged-pion chemical potential is evaluated. We utilize a conventional effective π-ρ Lagrangian and the functional integral representation of the partition function in the second order in the ρππ coupling constant. We analyze the gauge invariant rho meson polarization operator and its dependence on the invariant mass M and spatial momentum vertical stroke pvertical stroke of the ρ meson. The pole positions and the values of the imaginary parts of the self-energy for different polarization states have different functional dependences on M and vertical stroke pvertical stroke . The corresponding dielectron rate (calculated from the imaginary part of the polarization operators) shows a distinctive asymmetry when the momentum t=p + -p - is perpendicular or parallel to p, where p ± are the momenta of the electron pair. (orig.)

  12. ρ-meson self-energy and dielectron emissivity in an isospin-asymmetric pion medium

    International Nuclear Information System (INIS)

    Titov, A.I.; Gulamov, T.I.; Kaempfer, B.

    1996-01-01

    The ρ-meson self-energy in an isospin-asymmetric pion gas at finite temperature and charged-pion chemical potential is evaluated. We utilize a conventional effective π-ρ Lagrangian and the functional integral representation of the partition function in the second order in the ρππ coupling constant. We analyze the ρ-meson polarization operator and its dependence on the invariant mass M and spatial momentum parallel p parallel of the ρ meson. The pole positions and the values of the imaginary parts of the self-energy for different polarization states have different functional dependences on M and parallel p parallel. The corresponding dielectron rate (calculated from the imaginary part of the in-medium ρ-meson propagator) shows a distinctive asymmetry when the momentum t=p + -p - is perpendicular or parallel to p, where p ± are the e ± momenta of the electron pair. copyright 1996 The American Physical Society

  13. Parity violation experiments at intermediate energies

    International Nuclear Information System (INIS)

    Van Oers, W.T.H.

    1996-06-01

    The status of the TRIUMF 221 MeV proton-proton violation experiment is reviewed. Several other proton-proton parity violation experiments in the in the intermediate energy range, currently in various stages of preparation, are discussed. A new experiment at an energy of 5.13 GeV (and if confirmed also at an energy of tens of GeV) is needed to follow on the earlier unexpected large result obtained at 5.13 GeV. (author)

  14. Isospin violation in low-energy pion-nucleon scattering revisited

    Energy Technology Data Exchange (ETDEWEB)

    Hoferichter, Martin, E-mail: hoferichter@hiskp.uni-bonn.d [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (IKP-3), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)

    2010-02-01

    We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently included. As an application, we discuss the energy dependence of the triangle relation that connects elastic scattering on the proton pi{sup +}-p->pi{sup +}-p with the charge exchange reaction pi{sup -}p->pi{sup 0}n.

  15. Isospin violation in low-energy pion-nucleon scattering revisited

    International Nuclear Information System (INIS)

    Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.

    2010-01-01

    We calculate isospin breaking in pion-nucleon scattering in the threshold region in the framework of covariant baryon chiral perturbation theory. All effects due to quark mass differences as well as real and virtual photons are consistently included. As an application, we discuss the energy dependence of the triangle relation that connects elastic scattering on the proton π ± p→π ± p with the charge exchange reaction π - p→π 0 n.

  16. Pion elastic scattering from polarized 13C in the energy region of the P33 resonance

    International Nuclear Information System (INIS)

    Yifen, Yen

    1992-08-01

    Asymmetries (A y ) and differential cross sections (dσ/dΩ) were measured for π + and π - elastic scattering using polarized and unpolarized 13 C targets. The experiment was done at the Los Alamos Meson Physics Facility with the pion beam from the Low Energy Pion channel. The scattered pions were detected with the Large Acceptance Spectrometer. The 13 C nuclei in 13 C-enriched 1-butanol were polarized by the dynamic nuclear polarilization method. Angular distributions of both A y and dσ/dΩ were measured below the P 33 resonance at the incident energy of 130 MeV for π + and π - , and above the resonance at 223 MeV for π + and at 226 MeV for π - . In addition, A y and dσ/dΩ were measured in a range of momentum transfers, 1.75 ≤ q ≤ 2.05 fm - , at several energies. At 130 MeV, the values of A y are significantly different from zero for π - scattering. For π + at 130 MeV and for both π - and π + at all other energies, the A y are mostly consistent with zero. Theoretical analyses were done using different nuclear structure models. The data were not reproduced by the presently available nuclear wave functions. It was found that the asymmetry is strongly sensitive to the quadrupole spin flip part of the transition. The data of this thesis complement measurements of the magnetic form factor from electron scattering. In attempts to fit both the asymmetry and the magnetic form factor, it was found that the pion asymmetry data are not reproduced by the wavefunctions which fit the magnetic form factor at low momentum transfers

  17. Pion minus energy measurement by a multilayer semiconductor spectrometer

    International Nuclear Information System (INIS)

    Gornov, M.G.; Gurov, Yu.B.; Lapushkin, S.V.

    1981-01-01

    A technique for determining π - meson energy by a laminated semiconductor spectrometer is described. Results of experimental test of the technique carried out using beams of meson track of the JINR synchrocyclotron and three Si(Li) detectors are given. A specific feature of the technique is that chi 2 criterium with a functional written through exact thicknesses of semiconductor detectors was used for separating events with disturbance of ionization dependence and determining particle energy. It is shown that the absolute resolution can be not worse than 0.5 MeV in a wide energy range. It is concluded that the technique suggested is suitable for measuring energy of any charged particles with indefinite energy release during stoppage [ru

  18. Charge exchange during pion-nucleon scattering at low energy: experiment and analysis

    International Nuclear Information System (INIS)

    Vernin, Pascal

    1972-01-01

    This research thesis lies within the frame of a more general study of pion-nucleon scattering according to the following processes: π + p → π + p; π - p → π - p; π - p → π 0 n. It more precisely addresses the last reaction, so-called charge exchange. Pion-nucleon interactions are described by phase shifts of scattering waves. But the measurement of one of these phase shifts (that of the S wave) requires very low energy pions, and could not have been performed until now with a good precision. In order to fill this gap, the author performed charge exchange experiments at 180 deg. and for energies of 22.6, 33.9 and 42.6 MeV. After a recall on involved theoretical data, the author describes the experimental setup, and reports the detailed study of problems raised by neutron detection. He shows that the analysis of experimental data allows (a 3 - a 1 ) to be obtained with a precision which, without being as high as desired, is nevertheless satisfying [fr

  19. Intermediate Energy Activation File (IEAF-99)

    International Nuclear Information System (INIS)

    Korovin, Yu.; Konobeev, A.; Pereslavtsev, P.; Stankovskij, A.; Fischer, U.; Moellendorff, U. von

    1999-01-01

    Nuclear data library IEAF-99, elaborated to study processes of interactions of intermediate energy neutrons with materials in accelerator driven systems, is described. The library is intended for activation and transmutation studies for materials irradiated by neutrons. IEAF-99 contains evaluated neutron induced reaction cross sections at the energies 0-150 MeV for 665 stable and unstable nuclei from C to Po. Approximately 50,000 excitation functions are included in the library. The IEAF-99 data are written in the ENDF-6 format combining MF = 3,6 MT = 5 data recording. (author)

  20. Intermediate-energy particle physics with real photons at the new direct-current accelerator ELSA

    International Nuclear Information System (INIS)

    Menze, D.

    1987-12-01

    The author reviews the physics of intermediate-energy photon interactions with nucleons and light nuclei. After a consideration of the photoproduction of mesons in the framework of the quark model and a description of the different polarization observables he discusses the photoproduction of pions, vector mesons, and kaons. In this connection the decay of baryon resonances of dibaryon resonances by photoexcitation of the deuteron are considered whereby also the polarization observables are described. Finally the photon reactions on three-nucleon systems are considered. (HSI)

  1. Multipole analyses and photo-decay couplings at intermediate energies

    International Nuclear Information System (INIS)

    Workman, R.L.; Arndt, R.A.; Zhujun Li

    1992-01-01

    The authors describe the results of several multipole analyses of pion-photoproduction data to 2 GeV in the lab photon energy. Comparisons are made with previous analyses. The photo-decay couplings for the delta are examined in detail. Problems in the representation of photoproduction data are discussed, with an emphasis on the recent LEGS data. 16 refs., 4 tabs

  2. Beam energy and centrality dependence of two-pion Bose-Einstein correlations at SPS energies

    International Nuclear Information System (INIS)

    Adamova, D.; Agakichiev, G.; Appelshaeuser, H.; Belaga, V.; Braun-Munzinger, P.; Campagnolo, R.; Castillo, A.; Cherlin, A.; Damjanovic, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S.I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glaessel, P.; Hering, G.; Holeczek, J.; Kushpil, V.; Lenkeit, B.; Ludolphs, W.; Maas, A.; Marin, A.; Milosevic, J.; Milov, A.; Miskowiec, D.; Musa, L.; Panebrattsev, Yu.; Petchenova, O.; Petracek, V.; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Richter, M.; Sako, H.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Seipp, W.; Sharma, A.; Shimansky, S.; Slivova, J.; Specht, H.J.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, I.; Wessels, J.P.; Wienold, T.; Windelband, B.; Wurm, J.P.; Xie, W.; Yurevich, S.; Yurevich, V.V.

    2003-01-01

    Results are presented of a two-pion interferometry (HBT) analysis in Pb+Au collisions at 40, 80, and 158 A GeV. A detailed study of the Bertsch-Pratt HBT radius parameters has been performed as function of the mean pair transverse momentum k t and in bins of the centrality of the collision. From these results we extract model-dependent information about the space-time evolution of the reaction. An investigation of the effective volume of the pion emitting system provides an important tool to study the properties of thermal pion freeze-out

  3. Beam energy and centrality dependence of two-pion Bose-Einstein correlations at SPS energies

    Energy Technology Data Exchange (ETDEWEB)

    Adamova, D.; Agakichiev, G.; Appelshaeuser, H. E-mail: appels@physi.uni-heidelberg.de; Belaga, V.; Braun-Munzinger, P.; Campagnolo, R.; Castillo, A.; Cherlin, A.; Damjanovic, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S.I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glaessel, P.; Hering, G.; Holeczek, J.; Kushpil, V.; Lenkeit, B.; Ludolphs, W.; Maas, A.; Marin, A.; Milosevic, J.; Milov, A.; Miskowiec, D.; Musa, L.; Panebrattsev, Yu.; Petchenova, O.; Petracek, V.; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Richter, M.; Sako, H.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Seipp, W.; Sharma, A.; Shimansky, S.; Slivova, J.; Specht, H.J.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, I.; Wessels, J.P.; Wienold, T.; Windelband, B.; Wurm, J.P.; Xie, W.; Yurevich, S.; Yurevich, V.V

    2003-02-10

    Results are presented of a two-pion interferometry (HBT) analysis in Pb+Au collisions at 40, 80, and 158 A GeV. A detailed study of the Bertsch-Pratt HBT radius parameters has been performed as function of the mean pair transverse momentum k{sub t} and in bins of the centrality of the collision. From these results we extract model-dependent information about the space-time evolution of the reaction. An investigation of the effective volume of the pion emitting system provides an important tool to study the properties of thermal pion freeze-out.

  4. Transverse Phenomena in Pion Production in Hadronic Collisions at SPS energy

    CERN Document Server

    Chvála, Ondrej

    A comparative study of pion production in hadronic collisio ns at SPS energies focusing on transverse phenomena is presented. Charged pion densities in p+p, p+C, p+Pb and Pb+Pb interactions, obtained at the CERN SPS with the NA49 detecto r setup, are discussed in the forward hemisphere covering ranges in Feynman x F between 0 and 0.4 and in transverse momentum from 0 to 2.1 GeV/c. A detailed description of the da ta analysis, the corrections and centrality determination is given for p+Pb interaction s using a sample of 2 M events. These data are compared to p+p collisions in order to extract those physics quantities which indicate deviations from the elementary reaction specific t o the presence of the nucleus. The evolution of these quantities as a function of centrality is discussed. Their comparison to p+C and Pb+Pb collisions reveals a smooth dependence on the n umber of collisions per participant. In particular, the enhancement of pion yields at high transverse momentum is studied. It is shown to be gove...

  5. delta. -isobars and photodisintegration at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Suzumura, Jun-ichi; Futami, Yasuhiko [Science Univ. of Tokyo, Noda, Chiba (Japan). Faculty of Science and Technology

    1982-12-01

    The dynamics of the peak considered to be due to the two-nucleon process in the reaction /sup 9/Be(gamma, p) anything is investigated with the quasi-deuteron model. We show that the process is dominated by a two-nucleon mechanism with pion and rho-meson exchange through virtual delta-isobar formation (author).

  6. Photoneutron multiplicities of preactinide nuclei at energies above the pion threshold

    International Nuclear Information System (INIS)

    Arruda-Neto, J.D.T.; Simionatto, S.; Likhachev, V.P.; Garcia, F.; Mesa, J.

    1998-01-01

    The average photoneutron multiplicities anti ν of Au, Ta and 182 W were deduced from their previously measured excitation energies anti E x , from 160 to 250 MeV. A combined analysis of these data and those measured at Saclay up to 140 MeV allowed the extraction of information on anti E x at the ''pure evaporation'' and quasideuteron energy regions. A theoretical approach for the study of anti ν above 140 MeV, which incorporates photopion reabsorption processes by two-body, was proposed, allowing a tentative delineation of the pion mean free path in the nucleus. (orig.)

  7. Extracting the σ-term from low-energy pion-nucleon scattering

    Science.gov (United States)

    Ruiz de Elvira, Jacobo; Hoferichter, Martin; Kubis, Bastian; Meißner, Ulf-G.

    2018-02-01

    We present an extraction of the pion-nucleon (π N) scattering lengths from low-energy π N scattering, by fitting a representation based on Roy-Steiner equations to the low-energy data base. We show that the resulting values confirm the scattering-length determination from pionic atoms, and discuss the stability of the fit results regarding electromagnetic corrections and experimental normalization uncertainties in detail. Our results provide further evidence for a large π N σ-term, {σ }π N=58(5) {{MeV}}, in agreement with, albeit less precise than, the determination from pionic atoms.

  8. Fission cross section measurements at intermediate energies

    International Nuclear Information System (INIS)

    Laptev, Alexander

    2005-01-01

    The activity in intermediate energy particle induced fission cross-section measurements of Pu, U isotopes, minor actinides and sub-actinides in PNPI of Russia is reviewed. The neutron-induced fission cross-section measurements are under way in the wide energy range of incident neutrons from 0.5 MeV to 200 MeV at the GNEIS facility. In number of experiments at the GNEIS facility, the neutron-induced fission cross sections were obtained for many nuclei. In another group of experiments the proton-induced fission cross-section have been measured for proton energies ranging from 200 to 1000 MeV at 100 MeV intervals using the proton beam of PNPI synchrocyclotron. (author)

  9. Multifragmentation in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Jacak, B.V.; Britt, H.C.; Claesson, G.

    1986-01-01

    There has been considerable recent interest in the production of intermediate mass fragments (A > 4) in intermediate and high energy nucleus-nucleus collisions. The mechanism for production of these fragments is not well understood and has been described by models employing a variety of assumptions. Some examples are: disassembly of a system in thermal equilibrium into nucleons and nuclear fragments, liquid-vapor phase transitions in nuclear matter, final state coalescence of nucleons and dynamical correlations between nucleons at breakup. Previous studies of fragment production, with one exception, have been single particle inclusive measurements; the observed fragment mass (or charge) distributions can be described by all of the models above. To gain insight into the fragment production mechanism, the authors used the GSI/LBL Plastic Ball detector system to get full azimuthal coverage for intermediate mass fragments in the forward hemisphere in the center of mass system while measuring all the light particles in each event. The authors studied the systems 200 MeV/nucleon Au + Au and Au + Fe

  10. Neutrino-nucleus collision at intermediate energy

    International Nuclear Information System (INIS)

    Kosmas, T.S.; Oset, E.

    1999-01-01

    Neutrino-nucleus reactions at low and intermediate energy up to E ν = 500 MeV are studied for the most interesting nuclei from an experimental point of view. We focus on neutrino-nucleus cross-sections of semi-inclusive processes, for which recent measurements from radiochemical experiments at LAMPF and KARMEN laboratories are available. The method employed uses the modified Lindhard function for the description of the particle-hole excitations of the final nucleus via a local density approximation. (authors)

  11. Photofissility of heavy nuclei at intermediate energies

    International Nuclear Information System (INIS)

    Deppman, A.; Arruda Neto, J.D.T.; Likhachev, V.P.; Goncalves, M.

    2002-10-01

    We use the recently developed MCMC/MCEF (Multi Collisional Monte Carlo plus Monte Carlo for Evaporation-Fission calculations) model to calculate the photo fissility and the photofission cross section at intermediate energies for the 243 Am and for 209 Bi, and compare them to results obtained for other actinides and to available experimental data. As expected, the results for 243 Am are close to those for 237 Np. The fissility for pre actinide nuclei is nearly one order of magnitude lower than that for the actinides. Both fissility and photofission cross section for 209 Bi are in good agreement with the experimental data. (author)

  12. Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

    International Nuclear Information System (INIS)

    Jacob, N.P. Jr.

    1975-07-01

    The effect of free-particle collisions in simple ''knockout'' reactions of the form (a,aN) and in more complex nuclear reactions of the form (a,X) was investigated by using protons and pions. Cross sections for the 48 Ti(p,2p) 47 Sc and the 74 Ge(p,2p) 73 Ga reactions were measured from 0.3 to 4.6 GeV incident energy. The results indicate a rise in (p,2p) cross section for each reaction of about (25 +- 3) percent between the energies 0.3 and 1.0 GeV, and are correlated to a large increase in the total free-particle pp scattering cross sections over the same energy region. Results are compared to previous (p,2p) excitation functions in the GeV energy region and to (p,2p) cross section calculations based on a Monte Carlo intranuclear cascade-evaporation model. Cross section measurements for (π/sup +-/, πN) and other more complex pion-induced spallation reactions were measured for the light target nuclei 14 N, 16 O, and 19 F from 45 to 550 MeV incident pion energy. These measurements indicate a broad peak in the excitation functions for both (π,πN) and (π,X) reactions near 180 MeV incident energy. This corresponds to the large resonances observed in the free-particle π + p and π - p cross sections at the same energy. Striking differences in (π,πN) cross section magnitudes are observed among the light nuclei targets. The experimental cross section ratio sigma(π - ,π - n)/sigma(π + ,πN) at 180 MeV is 1.7 +- 0.2 for all three targets. The experimental results are compared to previous pion and analogous proton-induced reactions, to Monte Carlo intranuclear cascade-evaporation calculations, and to a semi-classical nucleon charge exchange model. (108 references) (auth)

  13. Transfer and breakup reactions at intermediate energies

    International Nuclear Information System (INIS)

    Stokstad, R.G.

    1986-04-01

    The origin of the quasi-elastic peak in peripheral heavy-ion reactions is discussed in terms of inelastic scattering and transfer reactions to unbound states of the primary projectile-like fragment. The situation is analogous to the use of reverse kinematics in fusion reactions, a technique in which the object of study is moving with nearly the beam velocity. It appears that several important features of the quasi-elastic peak may be explained by this approach. Projectile-breakup reactions have attractive features for the study of nuclear structure. They may also be used to determine the partition of excitation energy in peripheral reactions. At intermediate energies, neutron-pickup reactions leading to four-body final states become important. Examples of experiments are presented that illustrate these points. 15 refs., 14 figs

  14. q-Gamow states for intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Plastino, A. [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina); Rocca, M.C., E-mail: mariocarlosrocca@gmail.com [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina); Ferri, G.L. [Fac. de C. Exactas, National University La Pampa, Peru y Uruguay, Santa Rosa, La Pampa (Argentina); Zamora, D.J. [La Plata National University and Argentina' s National Research Council, (IFLP-CCT-CONICET)-C. C. 727, 1900 La Plata (Argentina)

    2016-11-15

    In a recent paper Plastino and Rocca (2016) [18] we have demonstrated the possible existence of Tsallis' q-Gamow states. Now, accelerators' experimental evidence for Tsallis' distributions has been ascertained only at very high energies. Here, instead, we develop a different set of q-Gamow states for which the associated q-Breit–Wigner distribution could easily be found at intermediate energies, for which accelerators are available at many locations. In this context, it should be strongly emphasized Vignat and Plastino (2009) [2] that, empirically, one never exactly and unambiguously “detects” pure Gaussians, but rather q-Gaussians. A prediction is made via Eq. (3.4).

  15. Magnetic polarizability of pion

    Energy Technology Data Exchange (ETDEWEB)

    Luschevskaya, E.V., E-mail: luschevskaya@itep.ru [Institute for Theoretical and Experimental Physics, Bolshaia Cheremushkinskaia 25, 117218 Moscow (Russian Federation); School of Biomedicine, Far Eastern Federal University, 690950 Vladivostok (Russian Federation); Solovjeva, O.E., E-mail: olga.solovjeva@itep.ru [Institute for Theoretical and Experimental Physics, Bolshaia Cheremushkinskaia 25, 117218 Moscow (Russian Federation); Teryaev, O.V., E-mail: teryaev@theor.jinr.ru [Joint Institute for Nuclear Research, Dubna, 141980 (Russian Federation); National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Kashirskoe highway, 31, 115409 Moscow (Russian Federation)

    2016-10-10

    We explore the energy dependence of π mesons off the background Abelian magnetic field on the base of quenched SU(3) lattice gauge theory and calculate the magnetic dipole polarizability of charged and neutral pions for various lattice volumes and lattice spacings. The contribution of the magnetic hyperpolarizability to the neutral pion energy has been also found.

  16. Pion form factor

    Energy Technology Data Exchange (ETDEWEB)

    Ryong Ji, C.; Pang, A.; Szczepaniak, A. [North Carolina State Univ., Raleigh, NC (United States)

    1994-04-01

    It is pointed out that the correct criterion to define the legal PQCD contribution to the exclusive processes in the lightcone perturbative expansion should be based on the large off-shellness of the lightcone energy in the intermediate states. In the lightcone perturbative QCD calculation of the pion form factor, the authors find that the legal PQCD contribution defined by the lightcone energy cut saturates in the smaller Q{sup 2} region compared to that defined by the gluon four-momentum square cut. This is due to the contribution by the highly off-energy-shell gluons in the end point regions of the phase space, indicating that the gluon four-momentum-square cut may have cut too much to define the legal PQCD.

  17. Pion production and fragmentation of nuclei in high energy nucleus-nucleus collisions

    International Nuclear Information System (INIS)

    Oskarsson, A.

    1983-01-01

    In collisions between nuclei at high energies one can study the behaviour of nuclear matter under extreme conditions, regarding nuclear density and temperature. The Bevalac and the CERN SC beams have been used and nuclear emulsion and scintillation telescopes have measured the reaction products. Collisions at 50A-200A MeV and at 2A GeV have been investigated. Proton spectra from 12 C induced reactions at 85A MeV have been recorded for different targets. Energetic protons at large angles can be assumed to be emitted from a source moving with half the beam velocity and a temperature between 13 and 17 MeV, depending on the target. In collisions between nuclei, pions can be produced below 290A MeV due to the internal Fermi motion of the nucleons. Subthreshold pion production has been studied for 12 C induced reactions at 85A and 75A Mev. The cross-sections are consistent with a quasi-free nucleon-nucleon scattering picture, involving Fermi motion, Pauli blocking and pion reabsorption. 16 C induced reactions in emulsion have been studied at 75A, 175A and 2000A MeV. It is shown that the excitation of the parts of the nuclei which are not overlapping (the spectators) increases with the beam energy. The 16 O projectile frequently breaks up into multiple He fragments. These events are associated with large impact parameters. Central collisions with Ag, Br target at 50A-110A MeV have been analysed separately. It is shown that the momentum transfer to the target nucleus is limited to a value considerably lower than the full momentum transfer in a fusion reactions. Events are observed where there are numerous fragments with 3< Z<8. These multifragmentation events cannot be understood in a thermal approach. (author)

  18. N → Δ (1232) electromagnetic transition form factor and pion-nucleon dynamics at moderate energies

    International Nuclear Information System (INIS)

    Jurewicz, A.

    1980-01-01

    The dependence of the electromagnetic N → Δ (1232) transition form factor G/sup asterisk//sub M/(q 2 ) on q 2 , the four-momentum transfer squared, has been calculated with the use of relativistic dispersion relations supplemented with some dynamical assumptions. In the first place, they regard the phase of the magnetic dipole amplitude of electroproduction of pions on nucleons in the p 33 final state beyond the region of elastic unitarity. Namely, over the range from the lowest inelastic threshold up to 1780 MeV pion-nucleon c.m. energy, the phase in question has been identified with the real part of the respective phase shift of pion-nucleon scattering. Secondly, contributions to the dispersion integral from the higher energy region have been neglected. Finally, the polynomial ambiguity which appears in the problem has been fixed by requiring that the foregoing amplitude of electroproduction vanishes, independently of q 2 , at the upper end of the integration interval as defined above. These assumptions which preserve unitarity were shown previously to lead to very good results when applied to the calculation of the multipole amplitudes M/sup() 3/2/ 1 /sub +/ and E/sup() 3/2/ 1 /sub +/ of photopion production on nucleons in the Δ (1232) region. Now it is also shown that G/sup asterisk//sub M/(q 2 ) calculated in that fashion follows remarkably well the data over the whole range 0 2 2 currently covered by quantitative experimental studies. Some speculation concerning a possible dynamical rooting of the foregoing assumptions is presented

  19. Electron scattering from sodium at intermediate energies

    International Nuclear Information System (INIS)

    Mitroy, J.; McCarthy, I.E.

    1986-10-01

    A comprehensive comparison is made between theoretical calculations and experimental data for intermediate energy (≥ 10 eV) electron scattering from sodium vapour. The theoretical predictions of coupled-channels calculations (including one, two or four channels) do not agree with experimental values of the differential cross sections for elastic scattering or the resonant 3s to 3p excitation. Increasingly-more-sophisticated calculations, incorporating electron correlations in the target states, and also including core-excited states in the close-coupling expansion, are done at a few selected energies in an attempt to isolate the cause of the discrepancies between theory and experiment. It is found that these more-sophisticated calculations give essentially the same results as the two- and four-channel calculations using Hartree-Fock wavefunctions. Comparison of the sodium high-energy elastic differential cross sections with those of neon suggests that the sodium differential cross section experiments may suffer from systematic errors. There is also disagreement, at the higher energies, between theoretical values for the scattering parameters and those that are derived from laser-excited superelastic scattering and electron photon coincidence experiments. When allowance is made for the finite acceptance angle of the electron spectrometers used in the experiments by convoluting the theory with a function representing the distribution of electrons entering the electron spectrometer it is found that the magnitudes of the differences between theory and experiment are reduced

  20. Fission in intermediate energy heavy ion reactions

    International Nuclear Information System (INIS)

    Wilhelmy, J.B.; Begemann-Blaich, M.; Blaich, T.; Boissevain, J.; Fowler, M.M.; Gavron, A.; Jacak, B.V.; Lysaght, P.S.; Britt, H.C.; Fields, D.J.; Hansen, L.F.; Lanier, R.G.; Massoletti, D.J.; Namboodiri, M.M.; Remington, B.A.; Sangster, T.C.; Struble, G.L.; Webb, M.L.; Chan, Y.D.; Dacai, A.; Harmon, A.; Leyba, J.; Pouliot, J.; Stokstad, R.G.; Hansen, O.; Levine, M.J.; Thorn, C.E.; Trautmann, W.; Dichter, B.; Kaufman, S.; Videbaek, F.; Fraenkel, Z.; Mamane, G.; Cebra, D.; Westfall, G.D.

    1989-01-01

    A systematic study of reaction mechanisms at intermediate energies (50-100 MeV/A) has been performed at the Lawrence Berkeley Laboratory's BeValac using medium weight projectiles on medium and heavy element targets. A gas and plastic phoswich detector system was employed which gave large geometric coverage and a wide dynamic response. The particles identified with the gas detectors could be characterized into three components - intermediate mass fragments (IMF), fission fragments (FF) and heavy residues (HR). Major observed features are: The reaction yields are similar in the 50 to 100 MeV/A range, central collisions have high multiplicty of IMF's with broad angular correlations consistent with a large participant region, effects of final state Coulomb interactions are observed and give information on the size and temporal behavior of the source, true fission yields are dependent on target fissility and correlated with relatively peripheral collisions. Analysis of fission and evaporation yields implies limiting conditions for which fission decay remains a viable deexcitation channel. (orig.)

  1. Fission in intermediate energy heavy ion reactions

    International Nuclear Information System (INIS)

    Wilhelmy, J.B.; Begemann-Blaich, M.; Blaich, T.

    1989-01-01

    A systematic study of reaction mechanisms at intermediate energies (50--100 MeV/A) has been performed at the Lawrence Berkeley Laboratory's BeValac using medium weight projectiles on medium and heavy element targets. A gas and plastic phoswich detector system was employed which gave large geometric coverage and a wide dynamic response. The particles identified with the gas detectors could be characterized into three components - intermediate mass fragments (IMF), fission fragments (FF) and heavy residues (HR). Major observed features are: the reaction yields are similar in the 50 to 100 MeV/A range, central collisions have high multiplicity of IMF's with broad angular correlations consistent with a large participant region, effects of final state Coulomb interactions are observed and give information on the size and temporal behavior of the source, true fission yields are dependent on target fissility and correlated with relatively peripheral collisions. Analysis of fission and evaporation yields implies limiting conditions for which fission decay remains a viable deexcitation channel. 7 figs

  2. Pion, pion-pion, and pion-nucleus interactions

    CERN Document Server

    Mukhin, K N; Tikhonov, V N

    2002-01-01

    This survey is devoted to describing the early studies of 1.1. Gurevich on pion physics that were performed by the photoemulsion method and the studies of the pion-pion interaction that were made by his colleagues on the basis of the hydrogen-bubble-chamber and the magnetic-spectrometer method (as well-as on the basis of the photoemulsion method). Two approaches-an extrapolation of experimental data from the physical region to the pion pole and a theoretical calculation based on the Roy integral equations-are used to deduce information about the pion-pion interaction. The first results obtained for pion-pion and pion-nucleus interactions in the experiments that are being currently performed in Brookhaven and at CERN ( pi pi interaction) and at TRIUMF (Canada) and in Brookhaven (pion-nucleus interaction) are presented, along with the existing theoretical concepts in these realms of physics. (80 refs).

  3. Intermediate and high energy nuclear reactions at the hadronic structural level

    Energy Technology Data Exchange (ETDEWEB)

    Slowinski, B [Institute of Physics, Warsaw, University of Technology, Poland, Institute of Atomic Energy, Swierk, (Poland)

    1997-12-31

    Form tens of MeV to several hundred of GeV is stretched out quite a large interval of energy when the interaction between hadrons (for instance, pion/nucleon-nucleus and nucleus-nucleus reactions) can be described by the considerably simplified way with still acceptable accuracy. This happens because in this energy region hadrons (i.e. pions, nucleons etc.) remain quasiparticles of nuclear matter mostly without revealing any internal structure, their de Broglie`s wavelength is much shorter as compared to the average intranuclear nucleon`s distance, and the energy transfers in the reaction are, on the average, significantly greater than the binding energy of nucleons inside nuclei. Consequently an approach to the analysis of these phenomena based on simple geometric and probabilistic considerations is justifiable, especially for many practical purposes, in particular, for shielding and dosimetric estimations, material behaviour prediction, as well as for the approximate evaluation of electronuclear breeding effects in different composites of target materials, for nuclear passivation problems and so on. In this work basic physical reasons of such a simplified picture of intermediate and high energy nuclear reactions are presented. The most usual phenomenological models of hadronic multiple emission/production and recent results of the cascade evaporation type models, are also discussed. 2 figs.

  4. Distributions of energy losses of electrons and pions in the CBM TRD

    International Nuclear Information System (INIS)

    Akishina, E.P.; Akishina, T.P.; Ivanov, V.V.; Denisova, O.Yu.

    2007-01-01

    The distributions of energy losses of electrons and pions in the TRD detector of the CBM experiment are considered. We analyze the measurements of the energy deposits in one-layer TRD prototype obtained during the test beam (GSI, Darmstadt, February 2006) and Monte Carlo simulations for the n-layered TRD realized with the help of GEANT in frames of the CBM ROOT. We show that 1) energy losses both for real measurements and GEANT simulations are approximated with a high accuracy by a log-normal distribution for π and a weighted sum of two log-normal distributions for e; 2) GEANT simulations noticeably differ from real measurements and, as a result, we have a significant loss in the efficiency of the e/π identification. A procedure to control and correct the process of the energy deposit of electrons in the TRD is developed

  5. Different aspects of nuclear physics from low energies up to intermediate energies

    International Nuclear Information System (INIS)

    Lallouet, Y.

    2011-12-01

    This study focuses on different aspects of nuclear physics from low energies to intermediate ones. For the low energies, the nuclear matter is essentially constituted from interacting nucleons. Part I is on the fusion-fission of super-heavy elements, while Part II is on the Skyrme interactions associated sum rules. In the case of the intermediate energies, where the nuclear matter is considered as being an hadronic phase mainly constituted from pions, Part III is focused on nuclear matter relativistic hydrodynamics with spontaneous chiral symmetry breaking. In Part I, the formation and the deexcitation of super-heavy nuclei are being studied. The memory effect must be taken into consideration within the super-heavy nuclei formation dynamics. Therefore we analyzed the formation of compound nuclei including the memory effects. As for the intermediate memory effects some oscillations appear, which is very different from the Markovian dynamics. For super-heavy nuclei deexcitation, the existence of isomeric state within the potential barrier cannot explain the results of experiments performed at GANIL with the crystal blocking technique, and this despite of the fact that it modifies the deexcitation dynamics and increases the fission time. However, this latter study could be useful for the study of the actinides fission. In Part II, the phenomenological Skyrme effective interactions-associated M 1 and M 3 sum rules are being calculated based on their intrinsic definitions. We identify then M 1 up to the tensorial level and M 3 with central potential. In Part III, as for the hadronic matter hydrodynamics being applied to heavy ions collisions, and as a first approach only, we can neglect spontaneous chiral symmetry but certainly not the dissipative impact. (author)

  6. Photonucleon reactions in 40Ca at intermediate energies

    International Nuclear Information System (INIS)

    Adler, J.-O.; Bulow, B.; Jonsson, G.G.; Lindgren, K.

    1976-01-01

    The yields of the reactions 40 Ca(γ,n) 39 Ca* and 40 Ca(γ,p) 39 K* to the first three excited states have been measured for bremsstrahlung with end-point energies in the region 100-750 MeV. The C 2 S values for the first excited state were deduced from the pion photoproduction contribution to the measured yields. (Auth.)

  7. Measurement of energy spectra of charged particles emitted after the absorption of stopped negative pions in carbon

    International Nuclear Information System (INIS)

    Mechtersheimer, G.

    1978-06-01

    The energy spectra of charged particles (p,d,t, 3 He, 4 He and Li-nuclei) emitted after the absorption of stopped negative pions in carbon targets of different thickness (1.227, 0.307, 0.0202 g/cm 2 ) have been measured from the experimental threshold energy of about 0.5 MeV up to the kinematical limit of about 100 MeV. The experiments have been carried out at the biomedical pion channel πE3 of the Swiss Institute of Nuclear Research (SIN). (orig.) [de

  8. Differential flux measurement of atmospheric pion, muon, electron and positron energy spectra at balloon altitudes

    Energy Technology Data Exchange (ETDEWEB)

    Grimani, C.; Brunetti, M.T.; Codino, A. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Papini, P.; Massimo Brancaccio, F.; Finetti, N. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Stephens, S.A. [Tata Institute of Fundamental Researc, Bombay (International Commission on Radiation Units and Measurements); Basini, G.; Bongiorno, F. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Golden, R.L. [New Mexico State Univ. Las Cruces, NM (United States). Particle Astrophysics Lab.

    1995-09-01

    The fluxes of atmospheric electrons, positrons, positive and negative muons and negative pions have been determined using the NMSU Wizard-MASS2 balloons-borne instrument. The instrument was launched from Fort Sumner, New Mexico, (geomagnetic cut-off about 4.5 GV/c) on september 23, 1991. The flight lasted 9.8 hours and remained above 100.000 ft. Muons and negative pions were observed and their momenta were determined. Since these particles are not a part of the primary component, the measurement of their fluxes provides information regarding production and propagation of secondary particles in the atmosphere. Similarly, observations of electrons and positrons well below the geomagnetic cut-off provides insight into electromagnetic cascade processes in the upper atmosphere. In addition, the determination of the energy spectra of rare particles such as positrons can be used for background subtraction for cosmic ray experiments gathering data below a few g/cm{sup 2} of overlying atmosphere.

  9. P-odd two-pion potentials and asymmetry of pp scattering at low energies

    International Nuclear Information System (INIS)

    Musakhanov, M.M.; Podgornov, Y.Y.

    1986-01-01

    The asymmetry of pp scattering A/sub p//sub p/ is calculated using the potential approach for incident proton energies of 15 and 45 MeV taking into account the isovector P-odd two-pion interaction. The corresponding 2π potentials are obtained in the static approximation of the noncovariant technique taking into account Δ-isobar configurations. The pion-baryon cutoff form factors are taken from chiral bag models. Owing to the lack of reliable information on the nucleon bag radius R, the contribution of 2π exchange to A/sub p//sub p/ is given for the fairly wide range R = 0.4--1.0 F. The strong interaction is taken into account by the introduction of the phenomenological Reid soft-core and Paris potentials. It is shown that most of the 2π-exchange contribution comes from the region where the internucleon separations are larger than they are where the contribution of rho 0 - and ω-meson exchange dominates and that the former contribution must be included in A/sub p//sub p/. The resulting contribution of the 2π potential to A/sub p//sub p/ is of the same order as the contribution of the rho 0 and ω potentials

  10. Selected problems in experimental intermediate energy physics

    International Nuclear Information System (INIS)

    Mayes, B.W.; Hungerford, E.V.; Pinsky, L.S.

    1990-09-01

    The objectives of this research program are to: investigate forefront problems in experimental intermediate energy physics; educate students in this field of research; and, develop the instrumentation necessary to undertake this experimental program. Generally, the research is designed to search for physical processes which cannot be explained by conventional models of elementary interactions. This includes the use of nuclear targets where the nucleus provides a many body environment of strongly perturbation of a known interaction by this environment. Unfortunately, such effects may be masked by the complexity of the many body problem and may be difficult to observe. Therefore, experiments must be carefully chosen and analyzed for deviations from the more conventional models. There were three major thrusts of the program; strange particle physics, where a strange quark is embedded in the nuclear medium; muon electro-weak decay, which involves a search for a violation of the standard model of the electro-weak interaction; and measurement of the spin dependent structure function of the neutron

  11. [Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    1989-01-01

    We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. The effort in quantum field theory provides theoretical results to test or replace assumed ingredients of the QCM. By the explicit example of a scalar field theory in 2D we have solved the long-standing problem of how to treat the dynamics of the vacuum in light-front quantization. We now propose to solve the same problem for simple Fermion field theories in 2D such as the Gross-Neveu model. We propose in subsequent years to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We have completed our analysis of the SLAC E101 and E133 experiments on Deuterium to elucidate the degree to which a six-quark cluster contribution is admissable in the Bjorken x > 1 data. We have completed our development of a parameterized thermal liquid drop model for light nuclei. In addition we have completed a set of predictions for the formation of a ''nuclear stratosphere'' in nuclei created by intermediate energy heavy ion interactions. These results motivate a new investigation of the temperature dependence of the ion-ion potential with particular emphasis on the thermal dependence of the barrier height and radius. We have also shown that a consistent treatment of relativistic effects is important for a theoretical description of the elastic magnetic form factor of 17 O. 85 refs

  12. Beam energy and centrality dependence of two-pion Bose-Einstein correlations at SPS energies

    Czech Academy of Sciences Publication Activity Database

    Adamová, Dagmar; Agakichiev, G.; Appelshäuser, H.; Belaga, V.; Braun-Munzinger, P.; Campagnolo, R.; Castillo, A.; Cherlin, A.; Damjanović, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S. I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glässel, P.; Hering, G.; Holeczek, J.; Kushpil, Vasilij; Lenkeit, B.; Ludolphs, W.; Maas, A.; Marín, A.; Milošević, J.; Milov, A.; Miśkowiec, D.; Musa, L.; Panebrattsev, Yu.; Petchenova, O.; Petráček, Vojtěch; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Richter, M.; Sako, H.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Seipp, W.; Sharma, A.; Shimansky, S.; Slívová, J.; Specht, H. J.; Stachel, J.; Šumbera, Michal; Tilsner, H.; Tserruya, I.; Wessels, J. P.; Wienold, T.; Windelband, B.; Wurm, J. P.; Xie, W.; Yurevich, S.; Yurevich, V. V.

    2003-01-01

    Roč. 714, 1/2 (2003), s. 124-144 ISSN 0375-9474 R&D Projects: GA ČR GA202/03/0879; GA AV ČR KSK1048102 Institutional research plan: CEZ:AV0Z1048901 Keywords : two-pion correlation function * heavy-ion collisions Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.761, year: 2003

  13. Final Technical Report - Nuclear Studies with Intermediate Energy Probes

    Energy Technology Data Exchange (ETDEWEB)

    Norum, Blaine [Univ. of Virginia, Charlottesville, VA (United States)

    2017-12-14

    During the almost 20 year period of this grant research was carried out on atomic nuclei and their constituents using both photons and electrons. Research was carried out at the electron accelerator facility of the Netherlands Institute for Nuclear and High Energy Physics (NIKHEFK, Amsterdam) until the electron accelerator facility was closed in 1998. Subsequently, research was carried out at the Laser-Electron Gamma Source (LEGS) of the National Synchrotron Light Source (NSLS) located at the Brookhaven National Laboratory (BNL) until the LEGS was closed at the end of 2006. During the next several years research was carried out at both the Thomas Jefferson National Accelerator Facility (JLAB) and the High Intensity Gamma Source (HIGS) of the Tri-Universities Nuclear Laboratory (TUNL) located on the campus of Duke University. Since approximately 2010 the principal focus was on research at TUNL, although analysis of data from previous research at other facilities continued. The principal early focus of the research was on the role of pions in nuclei. This was studied by studying the production of pions using both photons (at LEGS) and electrons (at NIKHEF-K and JLAB). Measurements of charged pion photoproduction from deuterium at LEGS resulted in the most interesting result of these two decades of work. By measuring the production of a charged pion (p + ) in coincidence with an emitted photon we observed structures in the residual two-nucleon system. These indicated the existence of long-lived states not explicable by standard nuclear theory; they suggest a set of configurations not explicable in terms of a nucleon-nucleon pair. The existence of such “exotic” structures has formed the foundation for most of the work that has ensued.

  14. Theoretical research in intermediate-energy nuclear physics. [Technical progress report, April 1, 1993--March 31, 1994

    International Nuclear Information System (INIS)

    Seki, R.

    1994-01-01

    This paper discusses progress that has been made on the following seven problems: (1) (e, e'p) at high momentum transfer; (2) post,acceleration effects in two-nucleon interferometry of heavy-ion collisions; (3) pion-nucleus interactions above 0.5 GeV; (4) chiral symmetry breaking in nuclei and picnic atom anomaly; (5) atomic screening on nuclear astronomical reactions; (6) QCD related work (coherent pion production from skyrmion-antiskyrmion annihilation, QCD in 1 + 1 dimensions, and correlation functions in the QCD vacuum), and (7) kaonic hydrogen atom experiment. The problems deal with various topics mostly in intermediate-energy nuclear physics. We place priority on (1) and (2), and describe them somewhat in detail below. Other problems are our on-going projects, but we are placing lower priority on them in the second and third year

  15. Polarization of protons produced in diffractive disintegration of deuterons by high-energy pions

    International Nuclear Information System (INIS)

    Gakh, G.Yi.; Rekalo, M.P.

    1996-01-01

    For the process of diffractive disintegration of unpolarized deuterons by the high-energy pions, π + d → π + p + n, the polarization characteristics of produced protons are calculated. Using the vector nature of the Pomeron exchange, the general structure of all components of proton polarization vector is found for d (π, π p) n. By the Pomeron-photon analogy, the amplitude of the process P + d → n + p is approximated by the isoscalar contribution of four Born diagrams similar to the case of deuteron electrodisintegration. Unitarization of the amplitude is achieved by introducing in multipole amplitudes the corresponding phases of np-scattering. The numerical calculation of all components of the polarization vector of protons, produced in the case of noncomplanar kinematics of the reaction π + d → π + p + n, is realized

  16. Bumping structure of initial energy density distributions and peculiarities of pion spectra in A + A collisions

    International Nuclear Information System (INIS)

    Borysova, M.S.

    2012-01-01

    The effect of a fluctuating bumping structure of the initial conditions on spectra and the collective evolution of matter created in heavy-ion collisions in the frameworks of the Hydro-Kinetic Model is investigated. As motivated by the glasma-flux-tube scenario, the initial conditions are modeled by the set of four high energy-density tube-like fluctuations with longitudinally homogeneous structure within some space-rapidity region in a boost-invariant 2D geometry. It was found that the presence of transversally bumping tube-like fluctuations in initial conditions strongly affects the hydrodynamic evolution and leads to emergence of conspicuous structures in the calculated pion spectra. It was observed that the 4 tube initial configuration generates a four-peak structure in the final azimuthal distributions of one-particle spectra.

  17. Nuclear structure at intermediate energies. Progress report

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.

    1992-01-01

    We report here oil the progress that we made for the nine months beginning October 1, 1991 for DOE Grant No. DE-FG05-87ER40309. The report covers the third year of a three year grant. Since we are submitting an accompanying Grant Renewal Proposal, we provide in this report more background information than usual for the different projects. The theme that unites the experiments undertaken by the Bonner Lab Medium Energy Group is a determination to understand in detail the many facets and manifestations of the strong interaction, that which is now referred to as nonperturbative QCD. Whether we are investigating the question of just what does carry the spin of baryons, or the extent of the validity of the SU(6) wavefunctions for the excited hyperons (as will be measured in our CEBAF experiment), or questions associated with the formation of a new state of matter predicted by QCD (the subject of AGS bar p experiment E854, AGS heavy ion experiment E810, as-well as the approved STAR experiment at RHIC), - all these projects share this common goal. FNAL E683 may well open a new field of investigation in nuclear physics: That of just how colored quarks and gluons interact with nuclear matter as they traverse nuclei of different-sizes. In most all of the experiments mentioned, above, the Bonner Lab Group is playing major leadership roles as well as doing a big fraction of the hard work that such experiments require. We use many of the facilities that are available to the intermediate energy physics community and we use our expertise to design and fabricate the detectors and instrumentation that are required to perform the measurements which we decide to do. The format we follow in the Progress Report is,to provide a concise, but fairly complete write-up on each project. The publications listed in Section In give much greater detail on many of the projects. The aim in this report is to focus on the physics goals, the results, and their significance

  18. System size and beam energy effects on probing the high-density behavior of nuclear symmetry energy with pion ratio

    International Nuclear Information System (INIS)

    Zhang Ming; Xiao Zhigang; Li Baoan; Chen Liewen; Yong Gaochan; Zhu Shengjiang

    2010-01-01

    Based on the isospin-and momentum-dependent hadronic transport model IBUU04, we have investigated the π - /π + ratio in the following three reactions: 48 Ca+ 48 Ca, 124 Sn + 124 Sn and 197 Au + 197 Au with nearly the same isospin asymmetry but different masses, at the bombarding energies from 0.25 to 0.6 AGeV. It is shown that the sensitivity of probing the E sym (ρ) with π - /π + increases with increasing the system size or decreasing the beam energy, showing a correlation to the degree of isospin fractionation. Therefore, with a given isospin asymmetry, heavier system at energies near the pion threshold is preferential to study the behavior of nuclear symmetry energy at supra-saturation densities.

  19. The expanding pion liquid and the pion spectra

    International Nuclear Information System (INIS)

    Ayala, A.

    1999-01-01

    We compute the pion inclusive momentum distribution in heavy-ion collisions for energies at the Alternating Gradient Synchrotron (AGS), assuming thermal equilibrium and accounting for density and expansion effects at freeze out. We compare to data on mid-rapidity charged pions produced in central Au + Au collisions and find a very good agreement. The shape of the distribution at low transverse mass is explained in part as an effect arising from the high mean pion density achieved in these reactions. The difference between the positive and negative pion distributions in the same region is attributed in part to the different average yields of each kind of charged pions. (Author)

  20. Pion photoproduction in the Skyrme model and low-energy theorem

    International Nuclear Information System (INIS)

    Saito, Sakae; Takeuchi, Fuminaka; Uehara, Masayuki

    1993-01-01

    We investigate pion photoproduction on the nucleon in the Skyrme model. We employ the formulation, which was recently developed by Hayashi et al., that the full pion field is treated as an interpolating field between asymptotic in and out fields. It is shown that the amplitude of the pion photoproduction is correctly given by the direct and the crossed baryon-pole terms, and the equal-time commutator terms between the axial-vector current and the electromagnetic current and between the pion field and the latter. We show that the lowest-order Kroll-Ruderman and the pion pole terms are reproduced, and that the seagull terms inherent to the Skyrme model are present. Further, the threshold behavior of the amplitude is discussed. (orig.)

  1. Energy dependence of negatively charged pion production in proton-proton interactions at the CERN SPS

    CERN Document Server

    AUTHOR|(SzGeCERN)663936; Dominik, Wojciech; Gaździck, Marek

    2016-01-01

    This thesis presents inclusive spectra of the negatively charged pions produced in inelastic proton-proton interactions measured at five beam momenta: 20, 31, 40, 80 and 158 GeV/c. The measurements were conducted in the NA61/SHINE experiment at CERN using a system of five Time Projection Chambers. The negatively charged pion spectra were calculated based on the negatively charged hadron spectra. Contribution of hadrons other than the primary pions was removed using EPOS simulations. The results were corrected for effects related to detection, acceptance, reconstruction efficiency and the analysis technique. Two-dimensional spectra were derived as a function of rapidity and transverse momentum or transverse mass. The spectra were parametrised by widths of the rapidity distributions, inverse slope parameters of the transverse mass distributions, mean transverse masses and the total pion multiplicities. The negatively charged pion spectra in proton-proton interactions belong to a broad NA61/SHINE programme of se...

  2. Magnetic effects in heavy-ion collisions at intermediate energies

    International Nuclear Information System (INIS)

    Ou Li; Li Baoan

    2011-01-01

    The time evolution and space distribution of internal electromagnetic fields in heavy-ion reactions at beam energies between 200 and 2000 MeV/nucleon are studied within an isospin-dependent Boltzmann-Uhling-Uhlenbeck transport model (ibuu11). While the magnetic field can reach about 7x10 16 G, which is significantly higher than the estimated surface magnetic field (∼1x10 15 G) of magnetars, it has almost no effect on nucleon observables because the Lorentz force is normally much weaker than the nuclear force. Very interestingly, however, the magnetic field generated by the projectilelike (targetlike) spectator has a strong focusing and defocusing effect on positive and negative pions at forward (backward) rapidities. Consequently, the differential π - /π + ratio as a function of rapidity is significantly altered by the magnetic field, whereas the total multiplicities of both positive and negative pions remain about the same. At beam energies above about 1 GeV/nucleon, while the integrated ratio of total π - to π + multiplicities is not, the differential π - /π + ratio is sensitive to the density dependence of nuclear symmetry energy E sym (ρ). Our findings suggest that magnetic effects should be carefully considered in future studies of using the differential π - /π + ratio as a probe of the E sym (ρ) at suprasaturation densities.

  3. Unified analysis of pionic atoms and low-energy pion-nuclear scattering: hybrid analysis

    International Nuclear Information System (INIS)

    Seki, R.; Masutani, K.; Yazaki, K.

    1983-01-01

    Using the method of effective nuclear density, we apply a simple, π-nucleus optical potential (without rho 2 terms and the Lorentz-Lorenz effect) to π - atoms and low-energy π-nucleus elastic scatterings. Data of both phenomena are analyzed in a unified, hybrid (phenomenological and theoretical) manner: The π - -atom data are analyzed first to determine phenomenologically the potential parameters at threshold. The parameters are then extrapolated successfully up to 50 MeV incident pion laboratory energy by a microscopic calculation in which the energy-dependence correction is made after including the Fermi-averaging and Pauli-blocking effects. In contrast to other work, our potential includes the minimum number of the parameters that describe the full information content of the data. We can thus conclude that these effects are the important microscopic corrections for the extrapolation, but neither the Lorentz-Lorenz effect nor some highly nonlocal effects are crucial ones. The potential we have used has angular transformation terms which are also found to be crucial in the unified treatment. During the course of this work we have found an interesting behavior of the terms. A short account of its discussion is also presented

  4. Generation and scaling behaviour of high-energy pions in relativistic heavy ion reactions

    International Nuclear Information System (INIS)

    Riess, F.

    1979-12-01

    Calculations with the help of a collision approximation as carried out in this study, are certainly linked with many uncertainties. The different forms of pulse distributions and cross sections used cover however such a broad region of possibilities, that even detailed calculations will not give any results essentially deviating from those obtained here. The various assumptions and statements could be relatively easily investigated using the collision approximation. Hence the above-mentioned aim, to pick out the principal information from the statement is achieved. It was shown that taking the two assumptions - nucleon-nucleon collisions only and - consideration of a cluster effect, in both cases the experimental results for a given reaction can be well reproduced as long as one only regards one projectile energy. It is important in the first case that the pulse distribution in the region of 0,5 to 1 GeV/c contains sufficiently large components - a simple Gauss distribution with a 'normal' parameter from nuclean physics is not sufficient here. The cluster statement provides the high-energy pions through the changed kinematics, compared to pure nucleon-nucleon collisions, and through the greater energy provided by a cluster in the reaction. (orig./HSI) [de

  5. Pion-nucleus scatter and the Pauli principle

    International Nuclear Information System (INIS)

    Dover, C.B.; Lemmer, R.H.

    1976-01-01

    A density expansion of the pion self-energy for pions in nuclear matter is reexamined. It is shown that a single hole-line expansion of the self-energy (i) is equivalent to using a strongly quenched πN scattering amplitude in the medium, and (ii) results in an inconsistent treatment of the virtual pions necessarily present in a field-theoretic description of the problem. Exchange of intermediate pions gives rise to nucleon-nucleon, as well as pion-nucleon scattering diagrams that both contribute to the pion self-energy in an essential way. The nucleon-nucleon scattering proceeds, for instance, via a one-pion-exchange potential that is, however, highly nonstatic for energy transfers between nucleons close to the incident energy. Such interactions are singled out automatically for special treatment in a field-theory approach to the problem, and should not be introduced in an ad hoc manner as part of an empirical NN interaction in nuclear matter. We evaluate the coherent and charge exchange contributions to the pion-nucleus optical potential, proportional to the total density and the neutron-proton density difference, respectively. The Pauli principle is found to provide a small correction to the coherent part, both in the hole-line and density expansion formalisms. However, the charge exchange part of the potential is almost completely damped at low energies in the hole-line expansion, while the inclusion of backward-going graphs (random-phase-approximation-type correlations) restores it to its value based on free space πN charge exchange amplitudes (i.e., no net Pauli effect)

  6. Beam-energy-dependent two-pion interferometry and the freeze-out eccentricity of pions measured in heavy ion collisions at the STAR detector

    Science.gov (United States)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2015-07-01

    We present results of analyses of two-pion interferometry in Au +Au collisions at √{sNN}=7.7 , 11.5, 19.6, 27, 39, 62.4, and 200 GeV measured in the STAR detector as part of the BNL Relativistic Heavy Ion Collider Beam Energy Scan program. The extracted correlation lengths (Hanbury-Brown-Twiss radii) are studied as a function of beam energy, azimuthal angle relative to the reaction plane, centrality, and transverse mass (mT) of the particles. The azimuthal analysis allows extraction of the eccentricity of the entire fireball at kinetic freeze-out. The energy dependence of this observable is expected to be sensitive to changes in the equation of state. A new global fit method is studied as an alternate method to directly measure the parameters in the azimuthal analysis. The eccentricity shows a monotonic decrease with beam energy that is qualitatively consistent with the trend from all model predictions and quantitatively consistent with a hadronic transport model.

  7. Nuclear energy density functional from chiral pion-nucleon dynamics revisited

    OpenAIRE

    Kaiser, N.; Weise, W.

    2009-01-01

    We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from $1\\pi$-exchange, iterated $1\\pi$-exchange, and irreducible $2\\pi$-exchange with intermediate $\\Delta$-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass $M^*(\\rho)$ entering the energy density functional is iden...

  8. Energy loss of pions and electrons of 1 to 6 GeV/c in drift chambers operated with Xe,CO2(15\\%)

    CERN Document Server

    Andronic, A; Braun-Munzinger, P; Bucher, D; Busch, O; Catanescu, V; Ciobanu, M; Daues, H W; Emschermann, D; Fateev, O V; Foka, Y; Garabatos, C; Gunji, T; Herrmann, N; Inuzuka, M; Kislov, E; Lindenstruth, V; Ludolphs, W; Mahmoud, T; Petracek, V; Petrovici, M; Rusanov, I R; Sandoval, A; Santo, R; Schicker, R; Simon, R S; Smykov, L P; Soltveit, H K; Stachel, J; Stelzer, H; Tsiledakis, G; Vulpescu, B; Wessels, J P; Windelband, B; Xu, C; Zaudtke, O; Zanevsky, Yu; Yurevich, V

    2004-01-01

    We present measurements of the energy loss of pions and electrons in drift chambers operated with a Xe,CO2(15%) mixture. The measurements are carried out for particle momenta from 1 to 6 GeV/c using prototype drift chambers for the ALICE TRD. Microscopic calculations are performed using input parameters calculated with GEANT3. These calculations reproduce well the measured average and most probable values for pions, but a higher Fermi plateau is required in order to reproduce our electron data. The widths of the measured distributions are smaller for data compared to the calculations. The electron/pion identification performance using the energy loss is also presented.

  9. Proceedings of the 6. National Meeting on Intermediate Energy Physics

    International Nuclear Information System (INIS)

    1986-01-01

    Several works on nuclear, hadron and quark physics are presented covering both aspects; theoretical and experimental, are presented. Emphasis is given in the intermediate energy region, several MeV centil few GeV. (L.C.) [pt

  10. Study of the response of the ATLAS central calorimeter to pions of energies from 3 to 9 GeV

    International Nuclear Information System (INIS)

    Abat, E.; Abdallah, J.M.; Addy, T.N.; Adragna, P.; Aharrouche, M.; Ahmad, A.; Akesson, T.P.A.; Aleksa, M.; Alexa, C.; Anderson, K.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.; Baker, O.K.; Banfi, D.; Baron, S.; Beck, H.P.

    2009-01-01

    A fully instrumented slice of the ATLAS central detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the response of the central calorimeters to pions with energies in the range between 3 and 9 GeV is presented. The linearity and the resolution of the combined calorimetry (electromagnetic and hadronic calorimeters) was measured and compared to the prediction of a detector simulation program using the toolkit Geant 4.

  11. Study of the response of the ATLAS central calorimeter to pions of energies from 3 to 9 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Abat, E [Bogazici University, Faculty of Sciences, Department of Physics, TR - 80815 Bebek-Istanbul (Turkey); Abdallah, J M [Institut de Fisica d' Altes Energies, IFAE, Universitat Autonoma de Barcelona, Edifici Cn, ES - 08193 Bellaterra, Barcelona (Spain); Addy, T N [Hampton University, Department of Physics, Hampton VA 23668 (United States); Adragna, P [Queen Mary, University of Landon, Mile End Road, E1 4NS London, United Kingdoom (United Kingdom); Aharrouche, M [Universitaet Mainz, Institut fuer Physik, Staudinger Weg 7, DE 55099 (Germany); Ahmad, A [Department of Physics and Astronomy, Stony Brook, NY 11794-3800 (United States); Akesson, T P.A. [Lunds universitet, Naturvetenskapliga fakulteten, Fysiska institutionen, Box 118, SE - 221 00, Lund (Sweden); Aleksa, M [European Laboratory for Particle Physics (CERN), CH-1211 Geneva 23 (Switzerland); Alexa, C [National Institute of Physics and Nuclear Engineering (Bucharest -IFIN-HH), P.O. Box MG-6, R-077125 Bucharest (Romania); Anderson, K [University of Chicago, Enrico Fermi Institute, 5640 S. Ellis Avenue, Chicago, IL 60637 (United States); Anghinolfi, F [European Laboratory for Particle Physics (CERN), CH-1211 Geneva 23 (Switzerland); Antonaki, A; Arabidze, G [University of Athens, Nuclear and Particle Physics Department of Physics, Panepistimiopouli Zografou, GR 15771 Athens (Greece); Arik, E [Bogazici University, Faculty of Sciences, Department of Physics, TR - 80815 Bebek-Istanbul (Turkey); Baker, O K [Yale University, Department of Physics , PO Box 208121, New Haven, CT06520-8121 (United States); Banfi, D [Universita di Milano , Dipartimento di Fisica and INFN, via Celoria 16, IT - 20133 Milano (Italy); Baron, S [European Laboratory for Particle Physics (CERN), CH-1211 Geneva 23 (Switzerland); Beck, H P [University of Bern, Laboratory for High Energy Physics, Sidlerstrasse 5, CH - 3012 Bern (Switzerland)

    2009-08-11

    A fully instrumented slice of the ATLAS central detector was exposed to test beams from the SPS (Super Proton Synchrotron) at CERN in 2004. In this paper, the response of the central calorimeters to pions with energies in the range between 3 and 9 GeV is presented. The linearity and the resolution of the combined calorimetry (electromagnetic and hadronic calorimeters) was measured and compared to the prediction of a detector simulation program using the toolkit Geant 4.

  12. Intermediate-energy neutron beams from reactors for NCT

    International Nuclear Information System (INIS)

    Brugger, R.M.; Less, T.J.; Passmore, G.G.

    1986-01-01

    This paper discusses ways that a beam of intermediate-energy neutrons might be extracted from a nuclear reactor. The challenge is to suppress the fast-neutron component and the gamma-ray component of the flux while leaving enough of the intermediate-energy neutrons in the beam to be able to perform neutron capture therapy in less than an hour exposure time. Moderators, filters, and reflectors are considered. 11 references, 7 figures, 3 tables

  13. Processing and validation of intermediate energy evaluated data files

    International Nuclear Information System (INIS)

    2000-01-01

    Current accelerator-driven and other intermediate energy technologies require accurate nuclear data to model the performance of the target/blanket assembly, neutron production, activation, heating and damage. In a previous WPEC subgroup, SG13 on intermediate energy nuclear data, various aspects of intermediate energy data, such as nuclear data needs, experiments, model calculations and file formatting issues were investigated and categorized to come to a joint evaluation effort. The successor of SG13, SG14 on the processing and validation of intermediate energy evaluated data files, goes one step further. The nuclear data files that have been created with the aforementioned information need to be processed and validated in order to be applicable in realistic intermediate energy simulations. We emphasize that the work of SG14 excludes the 0-20 MeV data part of the neutron evaluations, which is supposed to be covered elsewhere. This final report contains the following sections: section 2: a survey of the data files above 20 MeV that have been considered for validation in SG14; section 3: a summary of the review of the 150 MeV intermediate energy data files for ENDF/B-VI and, more briefly, the other libraries; section 4: validation of the data library against an integral experiment with MCNPX; section 5: conclusions. (author)

  14. The two-nucleon system above pion threshold

    International Nuclear Information System (INIS)

    Poepping, H.; Sauer, P.U.; Zhang Xizhen

    1987-01-01

    A force model is presented for the description of the two-nucleon system below and above pion threshold and its coupled inelastic channels with one pion. It uses Δ-isobar and pion degrees of freedom in addition to the nucleonic one. The force model is based on a hamiltonian approach within the framework of noncovariant quantum mechanics. It extends the traditional approach with purely nucleonic potentials in isospin-triplet partial waves. It is constructed to remain valid up to 500 MeV c.m. energy. The characteristics of the force model is its mechanism for pion production and pion absorption which is mediated by the Δ-isobar. Even without any fit of phenomenological parameters the force model is able to account for the experimental data of elastic nucleon-nucleon scattering' of the inelastic reactions pp ↔ π + d and of elastic pion-deuteron scattering with satisfactory accuracy. No need for the introduction of dibaryon degrees of freedom has been found yet. The force model is a realistic one in the two-nucleon system. In many-nucleon systems it forms the unifying basis for a microscopic description of nuclear structure and nuclear reactions at low and intermediate energies. (orig.)

  15. Breakup reactions at intermediate and high energy

    International Nuclear Information System (INIS)

    Shotter, A.C.; Bice, A.N.

    1981-01-01

    Having considered some general aspects of peripheral break-up reactions involving heavy ions for the incident energy range 10-2000 MeV/A, specific experiments carried out at Berkeley in 1980 in the energy range 10-20 MeV/A are discussed. These indicate that sequential break-up processes from non-sequential inelastic processes both play significant roles in the mechanism. (UK)

  16. Dynamical effects in multifragmentation at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Colin, J.; Cussol, D.; Normand, J. [Caen Univ., Lab. de Physique Corpusculaire, IN2P3-CNRS/ENSICAEN, 14 (France)] [and others

    2003-04-01

    The fragmentation of the quasi-projectile is studied with the INDRA multidetector for different colliding systems and incident energies in the Fermi energy range. Different experimental observations show that a large part of the fragmentation is not compatible with the statistical fragmentation of a fully equilibrated nucleus. The study of internal correlations is a powerful tool, especially to evidence entrance channel effects. These effects have to be included in the theoretical descriptions of nuclear multifragmentation. (authors)

  17. Charged pion coherent production in nucleus-nucleus collisions at incident energies between 86 and 330 MeV/nucleon

    International Nuclear Information System (INIS)

    Fassnacht, P.

    1984-01-01

    We have studied pion production in nucleus-nucleus collisions at foward angles for about twenty projectile target combinations. The incident energies were below or around 300 MeV/nucleon which is the threshold of the elementary reaction NN → NNπ. The study of the inclusive spectra shows some new ideas: shell effects in pion production, collective resonances excitations. These spectra have been analyzed following different models: hard-scattering models which describe the interaction on the basis of the elementary reaction NN → NNπ, statistical model and the pionic cloud model which is a coherent description of the interaction. In the study of the exclusive reactions, we established some empiric rules concerning the cross-section variations. These exclusive spectra were then analyzed in the framework of two-models: the semi-phenomenological model and the pionic fusion [fr

  18. Positron scattering by atomic hydrogen at intermediate energies

    International Nuclear Information System (INIS)

    Higgins, K.; Burke, P.G.; Walters, H.R.J.

    1990-01-01

    Results of an accurate calculation based upon the intermediate energy R-matrix theory are reported for elastic scattering of positrons by atomic hydrogen. T-matrix elements for both low and intermediate energy scattering are evaluated for the S e , P o , D e and F o partial wave symmetries. The low-energy elastic phaseshifts are found to be in good agreement with previous accurate variational calculations. Using an optical potential approach to include the effect of the higher partial waves, elastic and total cross sections are presented for energies ranging from near threshold to 3.7 Rydbergs. (author)

  19. Low energy constituent quark and pion effective couplings in a weak external magnetic field

    Science.gov (United States)

    Braghin, Fábio L.

    2018-03-01

    An effective model with pions and constituent quarks in the presence of a weak external background electromagnetic field is derived by starting from a dressed one gluon exchange quark-quark interaction. By applying the auxiliary field and background field methods, the structureless pion limit is considered to extract effective pion and constituent quark couplings in the presence of a weak magnetic field. The leading terms of a large quark and gluon masses expansion are obtained by resolving effective coupling constants which turn out to depend on a weak magnetic field. Two pion field definitions are considered for that. Several relations between the effective coupling constants and parameters can be derived exactly or in the limit of very large quark mass at zero and weak constant magnetic field. Among these ratios, the Gell-Mann-Oakes-Renner and the quark level Goldberger-Treiman relations are obtained. In addition to that, in the pion sector, the leading terms of Chiral Perturbation Theory coupled to the electromagnetic field are recovered. Some numerical estimates are provided for the effective coupling constants and parameters.

  20. Multiplicities of pions and slow protons in nuclear interactions at relativistic energies

    International Nuclear Information System (INIS)

    Idh, J.

    1993-02-01

    The distributions of the transverse energy and the multiplicity of charged particles in oxygen induced reactions are examined in the Fritiof Monte Carlo model. The shape of the distributions are found to be determined by the distribution of the number of particle-emitting sources, i.e. strings. The fluctuations in particle emission from each string is hidden by these much larger fluctuations. The fluctuations of these distributions when partial phase space coverage is used is well described by purely stochastic emission. Distributions of slow singly-charged fragments in the target region is measured for both hadron and oxygen induced reactions. The distributions extends to much larger values than simulated data from the Monte Carlo models Fritiof 1.7 and Venus 3.14. The hadron induced reactions give distributions that can be reproduced assuming that each participating target nucleon produced fragments according to a geometric distribution, where the average number of fragments per participating target nucleon is target dependent. The extracted average number of produced fragments are similar for proton and pion induced reactions. When the tails of the distributions are studied their extension can be parametrized, and for such an approach a target dependence of A 2/3 is found for all projectiles. The data for 60 and 200 A GeV are almost identical for distributions as well as angular and energy examined distributions. The angular distributions follow an exponential in cos(θ). If the slopes of the angular distributions are examined and target dependences as well as centrality dependences are extracted. For light targets there is a strong target dependence, but for targets heavier than copper there is not any great differences. The centrality dependence is almost negligible for a gold-target but for a copper-target the most central collisions have more forward peaked distributions. (62 refs.)

  1. Negotiating comfort in low energy housing: The politics of intermediation

    International Nuclear Information System (INIS)

    Grandclément, Catherine; Karvonen, Andrew; Guy, Simon

    2015-01-01

    Optimising the energy performance of buildings is technically and economically challenging but it also has significant social implications. Maintaining comfortable indoor conditions while reducing energy consumption involves careful design, construction, and management of the built environment and its inhabitants. In this paper, we present findings from the study of a new low energy building for older people in Grenoble, France where conflicts emerged over the simultaneous pursuit of energy efficiency and comfort. The findings contribute to the contemporary literature on the sociotechnical study of buildings and energy use by focusing on intermediation, those activities that associate a technology to end users. Intermediation activities take many forms, and in some cases, can result in the harmonisation or alignment of energy efficiency goals and comfort goals. In other cases, intermediation is unsuccessful, leading to the conventional dichotomy between optimising technical performance and meeting occupant preferences. By highlighting the multiple ways that comfort and energy efficiency is negotiated, we conclude that buildings are provisional achievements that are constantly being intermediated. This suggests that building energy efficiency policies and programmes need to provide opportunities for intermediaries to negotiate the desires and preferences of the multiple stakeholders that are implicated in low energy buildings. -- Highlights: •Energy efficiency and comfort are two possibly contradictory aims of buildings. •We study the pursuit of these aims at the occupation stage of a new building. •Aligning these aims involve negotiating them with occupants. •Intermediation processes are key to such negotiations. •Intermediation processes involve both actors and technical devices

  2. Microdosimetry of negative pions

    International Nuclear Information System (INIS)

    Amols, H.I.; Dicello, J.F.; Lane, T.F.

    1976-01-01

    The radiation quality of negative and positive pions of initial momentum 168MeV/c has been determined at eight different depths in a liquid phantom. The measurements were made with a 2.5cm diameter spherical proportional counter with Shonka A-150 neutron tissue equivalent plastic walls. The gas pressure in the sensitive volume was chosen to stimulate a diameter of 2μm in unit density material. Dose distributions as a function of lineal energy change slowly in the entrance and plateau regions with a dose mean lineal energy of 6-8keV/μm. Less than 3% of the dose is delivered in excess of 50keV/μm in this region. In the Bragg peak region the distributions change rapidly as a function of depth with the dose mean lineal energy increasing to 38keV/μm at the peak and to 57keV/μm just beyond the peak. On the basis of these microdosimetric data predictions of RBE and OER have been made with the use of both the theory of dual radiation action and also the delta ray theory of cell survival. The former has been used to predict biological response at low doses and the latter at high doses. A comparison is made between the two theories at intermediate doses. The results of these calculations are not inconsistant with recent biological data

  3. Heavy ion collisions at intermediate energy

    International Nuclear Information System (INIS)

    Bertsch, G.; Amsden, A.A.

    1978-01-01

    Two types of measurement are proposed for the analysis of heavy ion collisions in the range of energy of 20--200 MeV/A. First, measurement of the longitudinal component of the kinetic energy of the collision products characterizes the impact parameter of the collision. The distribution in this quantity allows the dissipation in the theoretical models to be determined. A second kind of measurement is that of the coefficients of a spherical harmonic expansion of the angular distribution of the products. Besides giving independent information on the impact parameter and reaction dynamics, measurement of these coefficients offers the possibility of measuring the stiffness of the equation of state of nuclear matter. These ideas are explored in the context of a hydrodynamic model for the collision. In the purely hydrodynamic model there is a large measurable asymmetry in the angular distribution, but the dependence on the equation of state is small

  4. Intermediate energy proton scattering from 10B

    International Nuclear Information System (INIS)

    Lewis, P.R.; Shute, G.G.; Spicer, R.S.; Henderson, R.S.

    1990-01-01

    Differential cross sections have been measured for 200 MeV proton scattering from 10 B. Data for six low lying natural parity levels below 6 MeV excitation energy are presented. Distorted wave analysis using a density dependent nucleon-nucleon interaction has assessed model spectroscopies of these excited states. The significance of the contribution from quadrupole scattering to the elastic cross section is discussed. 49 refs., 5 tabs., 21 figs

  5. Observations on transverse moments of pions neutral and gamma rays of intermediate mass state ∼3GeW/c2 (MIRIM) in meson multiple production

    International Nuclear Information System (INIS)

    Fauth, A.C.

    1986-01-01

    The transverse moment distribution of pions neutral of 32 mirin c-jets with ΣΕγ>20 TeV by tw methods of 2γ->Π 0 coupling. This results independ of any particle production model. A simulation of pion production by Monte Carlo method is carried out and it is shown that, the two methods provide to obtain approximately 50% of correct couplings. The form of pions neutral distribution depends weakly of the percentage of correct couplings. The pions neutral transverse moment distribution of Mirins events is obtained by a third model which is completely independent from the two first, which consists in a composition between an analytical solution and the Monte Carlo method. The results of the three methods are consistents among themselves. (M.C.K.) [pt

  6. Photofissility of actinide nuclei at intermediate energies

    International Nuclear Information System (INIS)

    Deppman, A.; Tavares, O.A.P.; Duarte, S.B.; Oliveira, E.C. de; Arruda-Neto, J.D.T.; Pina, S.R. de; Likhachev, V.P.; Mesa, J.; Goncalves, M.

    2001-08-01

    We analyze the recent experimental data on photofissility for 237 Np, 238 U, and 232 Th at incident photon energies above 200 MeV. For this analysis, we developed a Monte carlo algorithm for the nuclear evaporation process in photonuclear reactions. This code is used in association with the multi-collisional model for the photon-induced intranuclear cascade process. Our results show a good quantitative and qualitative agreement with the experimental data. It is shown that the emission of protons and alpha particles at the evaporation stage is an important component for the non-saturation of the actinides photofissility up to, at least, 1GeV. (author)

  7. Innovative spin precessor for intermediate energy protons

    International Nuclear Information System (INIS)

    Hoffman, E.W.

    1979-01-01

    A spin precessor has been designed to provide arbitrary orientation of the polarization in the external proton beam at LAMPF. The device utilizes two superconducting solenoids, three conventional dipoles, and conversion of polarized H - to H + to provide an achromatic, undeflected beam with tunable spin orientation over a range of energies from 400 MeV to 800 MeV. A portion of this device is being installed to provide compatibility between two facilities which simultaneously use two branches of the external proton beam at LAMPF

  8. Production and decay of baryonic resonances in pion induced reactions

    Directory of Open Access Journals (Sweden)

    Przygoda Witold

    2016-01-01

    Full Text Available Pion induced reactions give unique opportunities for an unambiguous description of baryonic resonances and their coupling channels. A systematic energy scan and high precision data, in conjunction with a partial wave analysis, allow for the study of the excitation function of the various contributions. A review of available world data unravels strong need for modern facilities delivering measurements with a pion beam. Recently, HADES collaboration collected data in pion-induced reactions on light (12C and heavy (74W nuclei at a beam momentum of 1.7 GeV/c dedicated to strangeness production. It was followed by a systematic scan at four different pion beam momenta (0.656, 0.69, 0.748 and 0.8 GeV/c in π− − p reaction in order to tackle the role of N(1520 resonance in conjunction with the intermediate ρ production. First results on exclusive channels with one pion (π− p and two pions (nπ+π−, pπ−π0 in the final state are discussed.

  9. Deuterons and flow: At intermediate AGS energies

    International Nuclear Information System (INIS)

    Kahana, D.E.; Pang, Y.; Kahana, S.H.

    1996-06-01

    A quantitative model, based on hadronic physics and Monte Carlo cascading is applied to heavy ion collisions at BNL-AGS and BEVALAC energies. The model was found to be in excellent agreement with particle spectra where data previously existed, for Si beams, and was able to successfully predict the spectra where data was initially absent, for Au beams. For Si + Au collisions baryon densities of three or four times the normal nuclear matter density (ρ 0 ) are seen in the theory, while for Au + Au collisions, matter at densities up to 10 ρ 0 is anticipated. The possibility that unusual states of matter may be created in the Au beams and potential signatures for its observation, in particular deuterons and collective flow, are considered

  10. Light fragment formation at intermediate energies

    International Nuclear Information System (INIS)

    Boal, D.H.

    1982-03-01

    This paper concerns itself mainly with the production of energetic protons and light fragments at wide angles. The experiments point to nucleon emission in proton-induced reactions as involving a mechanism in which the observed nucleon is directly knocked out of the nucleus. A similar feature seems to be required to explain (p,F) and (e,F) reactions: an energetic nucleon is produced in one scattering of the projectile, and the struck nucleon subsequently loses some of its energy as it traverses the remaining part of the nucleus, gathering up other nucleons as it goes, to become a fragment. This is what one might call the extreme snowball model, and a more accurate description probably involves multiple scattering of the projectile in addition to the extreme snowball contribution. This will be particularly true for fragments in the mass 6 to 9 region. This scenario also appears to apply to deuteron-induced fragment production. However, for alpha-induced reactions it would appear that the nucleons forming a fragment can originate from collisions involving different incident nucleons in the projectile. For heavy ions, this effect is even stronger, and the snowball contribution is greatly reduced compared to that of the traditional coalescence model

  11. Energy-independent multipole analysis of single-pion photoproduction from protons

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Sanin, V.M.; Telegin, Y.N.; Shalatskii, S.V.

    1983-08-01

    For the first time photoproduction multipole amplitudes are evaluated unambiguously on the basis of new experimental data on pion photoproduction from protons and the latest ..pi..N scattering phase shifts. The multipole amplitudes obtained are compared with the results of previous multipole analyses and dispersion-relation predictions.

  12. Energy-independent multipole analysis of single-pion photoproduction from protons

    International Nuclear Information System (INIS)

    Get'man, V.A.; Sanin, V.M.; Telegin, Y.N.; Shalatskii, S.V.

    1983-01-01

    For the first time photoproduction multipole amplitudes are evaluated unambiguously on the basis of new experimental data on pion photoproduction from protons and the latest πN scattering phase shifts. The multipole amplitudes obtained are compared with the results of previous multipole analyses and dispersion-relation predictions

  13. Intermediate-energy neutron beam for NCT at MURR

    International Nuclear Information System (INIS)

    Brugger, R.M.; Less, T.J.; Passmore, G.G.

    1986-01-01

    The University of Missouri Research Reactor (MURR) is one of the high-flux reactors in the USA and it can be used to produce an intense beam of intermediate-energy neutrons for neutron capture therapy. Two methods are being evaluated at MURR to produce such a beam. The first uses a moderator of Al 2 O 3 replacing part of the graphite and water on one side of the core of the reactor to produce a source of predominantly intermediate-energy neutrons. The second method is a filter of 238 U between the core and the patient position to pass only intermediate-energy neutrons. The results of these evaluations are presented in this paper along with an outline of the other resources at the University of Missouri-Columbia that are available to support an NCT program. 4 references, 7 figures, 1 table

  14. Microdosimetry of intermediate energy neutrons in fast neutron fields

    International Nuclear Information System (INIS)

    Saion, E.B.; Watt, D.E.

    1988-01-01

    A coaxial double cylindrical proportional counter has been constructed for microdosimetry of intermediate energy neutrons in mixed fields. Details are given of the measured gas gain and resolution characteristics of the counter for a wide range of anode voltages. Event spectra due to intermediate neutrons in any desired energy band is achieved by an appropriate choice of thickness of the common dividing wall in the counter and by appropriate use of the coincidence, anticoincidence pulse counting arrangements. Calculated estimates indicate that the dose contribution by fast neutrons to the energy deposition events in the intermediate neutron range may be as large as 25%. Empirical procedures being investigated aim to determine the necessary corrections to be applied to the microdose distributions, with a precision of 10%. (author)

  15. [Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    1987-01-01

    We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. We have solved a non-trivial model field theory in the strong coupling regime using a discretized light front quantization (DLFQ) scheme. The method we developed expands upon the method of Pauli and Brodsky by incorporating a dynamical treatment of the vacuum. This is a major result since we have shown directly that the light-cone vacuum is not structureless as has been traditionally claimed by some particle theorists. We have thus succeeded in elucidating the consequences of spontaneous symmetry breaking in light-cone quantization. We now propose to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We will complete our analysis of the SLAC NE3 data to explicate the degree to which they confirm the QCM prediction of ''steps'' in the ratio of nuclear structure functions when Bjorken x exceeds unity. In another effort, we will perform a search for narrow resonances in electron-positron interactions high in the continuum using the Bethe-Salpeter equation. We have completed our development of microscopic effective Hamiltonians for nuclear structure which include the explicit treatment of delta resonances. These effective Hamiltonians were successfully used in constrained mean field calculations evaluating conditions for nuclei to undergo a transition from nucleon matter to delta matter. 73 refs

  16. Pion-pair formation and the pion dispersion relation in a hot pion gas

    Energy Technology Data Exchange (ETDEWEB)

    Chanfay, G. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Alm, T. [Rostock Univ. (Germany); Schuck, P. [Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires; Welke, G. [Wayne State Univ., Detroit, MI (United States). Dept. of Physics and Astronomy

    1996-09-01

    The possibility of pion-pair formation in a hot pion gas, based on the bosonic gap equation, is pointed out and discussed in detail. The critical temperature for condensation of pion pairs (Evans-Rashind transition) is determined as a function of the pion density. As for fermions, this phase transition is signaled by the appearance of a pole in the two-particle propagator. In Bose systems there exists a second, lower critical temperature, associated with the appearance of the single-particle condensate. Between the two critical temperatures the pion dispersion relation changes from the usual quasiparticle dispersion to a Bogoliubov-like dispersion relation at low momenta. This generalizes the non-relativistic results for an attractive Bose gas by Evans et al. Possible consequences for the inclusive pion spectra measured in heavy-ion collisions at ultra-relativistic energies are discussed. 21 refs.

  17. Singlet channel coupling in deuteron elastic scattering at intermediate energies

    International Nuclear Information System (INIS)

    Al-Khalili, J.S.; Tostevin, J.A.; Johnson, R.C.

    1990-01-01

    Intermediate energy deuteron elastic scattering is investigated in a three-body model incorporating relativistic kinematics. The effects of deuteron breakup to singlet spin intermediate states, on the elastic scattering observables for the 58 Ni(d vector, d) 58 Ni reaction at 400 and 700 MeV, are studied quantitatively. The singlet-breakup contributions to the elastic amplitude are estimated within an approximate two-step calculation. The calculation makes an adiabatic approximation in the intermediate states propagator which allows the use of closure over the np intermediate states continuum. The singlet channel coupling is found to produce large effects on the calculated reaction tensor analysing power A yy , characteristic of a dynamically induced second-rank tensor interaction. By inspection of the calculated breakup amplitudes we show this induced interaction to be of the T L tensor type. (orig.)

  18. Fission cross sections in the intermediate energy region

    International Nuclear Information System (INIS)

    Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J.; Carlson, A.D.; Wasson, O.A.; Hill, N.W.

    1991-01-01

    Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for 235 U and 238 U compared to intranuclear cascade and statistical model predictions

  19. Fission cross sections in the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Lisowski, P.W.; Gavron, A.; Parker, W.E.; Ullmann, J.L.; Balestrini, S.J. (Los Alamos National Lab., NM (USA)); Carlson, A.D.; Wasson, O.A. (National Inst. of Standards and Technology, Gaithersburg, MD (USA)); Hill, N.W. (Oak Ridge National Lab., TN (USA))

    1991-01-01

    Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission cross section data for {sup 235}U and {sup 238}U compared to intranuclear cascade and statistical model predictions.

  20. Beam-energy dependence of the directed flow of protons, antiprotons, and pions in Au+Au collisions.

    Science.gov (United States)

    Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Davila Leyva, A; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; Derradi de Souza, R; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; Levine, M J; Li, C; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Madagodagettige Don, D M M D; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Poljak, N; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-04-25

    Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y=0) are reported in sNN=7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton dv1/dy|y=0 changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.

  1. Beam-Energy Dependence of the Directed Flow of Protons, Antiprotons, and Pions in Au+Au Collisions

    Science.gov (United States)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2014-04-01

    Rapidity-odd directed flow (v1) measurements for charged pions, protons, and antiprotons near midrapidity (y =0) are reported in √sNN =7.7, 11.5, 19.6, 27, 39, 62.4, and 200 GeV Au+Au collisions as recorded by the STAR detector at the Relativistic Heavy Ion Collider. At intermediate impact parameters, the proton and net-proton slope parameter dv1/dy|y=0 shows a minimum between 11.5 and 19.6 GeV. In addition, the net-proton dv1/dy|y=0 changes sign twice between 7.7 and 39 GeV. The proton and net-proton results qualitatively resemble predictions of a hydrodynamic model with a first-order phase transition from hadronic matter to deconfined matter, and differ from hadronic transport calculations.

  2. Pion source parameters in heavy ion collisions

    International Nuclear Information System (INIS)

    Crowe, K.M.; Bistirlich, J.A.; Bossingham, R.R.

    1984-12-01

    Following the early work of Goldhaber, Lee, and Pais, many experiments have used the momentum correlations between identical bosons to determine the space-time extent of the pion source for various reactions between elementary hadrons. This technique, known as intensity interferometry, has recently been applied to nuclear collisions at both intermediate and very high energies. Here we report on measurements of the radius and lifetime of the pion source in the reactions 1.8 A GeV 40 Ar + KCl → 2π/sup +-/ + X, 1.8 A GeV 20 Na + NaF → 2π - + X, and 1.71 A GeV 56 Fe + Fe → 2π - + X. 11 references

  3. Study of the response of the ATLAS central calorimeter to pions of energies from 3 to 9 GeV

    Czech Academy of Sciences Publication Activity Database

    Abat, E.; Abdallah, J.M.; Addy, T.N.; Lokajíček, Miloš; Němeček, Stanislav

    2009-01-01

    Roč. 607, č. 2 (2009), s. 372-386 ISSN 0168-9002 R&D Projects: GA MŠk LC527; GA MŠk LA08047 Institutional research plan: CEZ:AV0Z10100502 Keywords : ATLAS * calorimeter * pions Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.317, year: 2009 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TJM-4WHDD3N-5&_user=10&_coverDate=08%2F11%2F2009&_rdoc=1&_fmt=high&_orig=search&_sort=d&_do

  4. Mechanism of pion absorption in complex nuclei

    International Nuclear Information System (INIS)

    Doss, K.G.N.; Wharton, W.R.

    Basic geometrical arguments are used to analyze the A dependence of the total pion absorption cross section, the effective number of nucleons sharing the pion momentum and energy, and the proton yields from π + - and π - -induced reactions. The results are consistent with the pions penetrating some distance through the nuclear volume and annihilating on a pair of nucleons. 3 figures

  5. Theoretical research in intermediate energy nuclear physics: Final report

    International Nuclear Information System (INIS)

    Seki, R.

    1987-01-01

    This paper discusses the progress that has been made on the following problems: a numerical calculation of Skyrmiron scattering; (e,e'p) at high momentum transfer; spin-orbit nucleon-nucleon potential from Skyrme model; pionic atom anomaly; and field theory problems. The problems deal with various topics in intermediate-energy nuclear physics

  6. Proceedings of the 5. National Meeting on Intermediate Energy Physics

    International Nuclear Information System (INIS)

    1984-05-01

    Several papers concerning the physics at intermediate energies (∼ 100-1000MeV) are presented in this proceedings. Almost all the works show overlapping between Nuclear and Particles Physics. There is a predominance in theoretical papers. (L.C.) [pt

  7. Electron emission in collisions of intermediate energy ions with atoms

    International Nuclear Information System (INIS)

    Garibotti, C.R.

    1988-01-01

    The aim of this work, is the analysis of the processes of electronic emission produced in the collisions of small ions (H + , He ++ ) of intermediate energy (50 a 200 KeV/amu) with light gaseous targets. (A.C.A.G.) [pt

  8. Polarization phenomena in electromagnetic interactions at intermediate energies

    International Nuclear Information System (INIS)

    Burkert, V.

    1990-01-01

    Recent results of polarization measurements in electromagnetic interactions at intermediate energies are discussed. Prospects of polarization experiments at the new CW electron accelerators, as well as on upgraded older machines are outlined. It is concluded that polarization experiments will play a very important role in the study of the structure of the nucleon and of light nuclei. 72 refs

  9. An improved optical potential for low-energy pion-nucleus scattering

    International Nuclear Information System (INIS)

    Khankhasaev, M.Kh.; Topil'skaya, N.S.

    1988-01-01

    A new procedure for calculating the imaginary part the of Stricker, McManus and Carr (SMC) optical potential is proposed. It is based on an approximate expression for the pion-nucleon scattering amplitude including nuclear structure effects. It is shown that the resulting potential with the absorption parameters fitted to the pionic atom data provides a good description of the scattering up to 50 MeV

  10. Short range correlations in the pion s-wave self-energy of pionic atoms

    OpenAIRE

    Salcedo, L. L.; Holinde, K.; Oset, E.; Schütz, C.

    1995-01-01

    We evaluate the contribution of second order terms to the pion-nucleus s-wave optical potential of pionic atoms generated by short range nuclear correlation. The corrections are sizeable because they involve the isoscalar s-wave $\\pi N$ amplitude for half off-shell situations where the amplitude is considerably larger than the on-shell one. In addition, the s-wave optical potential is reanalyzed by looking at all the different conventional contributions together lowest order, Pauli corrected ...

  11. Energy-independent multiple analysis of one-pion photoproduction processes on protons

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Sanin, V.M.; Telegin, Yu.N.; Shalatskij, S.V. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst.)

    1983-08-01

    For the first time unambiguous estimates are obtained for the multipole photoproduction amplitudes which are based upon the new experimental data on the pion photoproduction on protons combined with the new estiamtes of the ..pi..N-scattering phase shifts. The obtained estimates of the multipole amplitudes are compared with the results of the previous multipole analyses and with the predictions based uoon the dispersion relations.

  12. Studies on the dynamics of heavy ion collisions at intermediate energies

    International Nuclear Information System (INIS)

    David, C.; Hartnack, C; Aichelin, J.

    1997-01-01

    We use the Quantum Molecular Dynamics model for the investigation of the dynamics of heavy ion collisions at intermediate energies. A detailed comparison between different versions of the models demonstrate the influence of not exactly known parameters in the description of nuclei like interaction range or initial densities and thus describes the limits of predictive power. The dynamics of the reaction are discussed quite similarly in the different models. A radial expansion with a linear velocity profile is found at central collisions. A strong interaction of pions with nuclear matter is reported. This interaction is strongly influenced by the lifetime of baryonic resonances in nuclear matter. These lifetimes depend strongly on the mass distribution of the resonances. These mass distributions are influenced by the momentum distribution in the nuclei. Here the inclusion of the spectral function shows visible effects. These effects influence the energy dissipation in nuclei and thus enter e.g. into the analysis of p + A collisions for the GEDEON project. (author)

  13. Probing the density dependence of the symmetry potential in intermediate-energy heavy ion collisions

    International Nuclear Information System (INIS)

    Li Qingfeng; Li Zhuxia; Soff, Sven; Gupta, Raj K; Bleicher, Marcus; Stoecker, Horst

    2005-01-01

    Based on the ultrarelativistic quantum molecular dynamics model, the effects of the density-dependent symmetry potential for baryons and of the Coulomb potential for produced mesons are investigated for neutron-rich heavy ion collisions at intermediate energies. The calculated results of the Δ - /Δ ++ and π - /π + production ratios show a clear beam-energy dependence on the density-dependent symmetry potential, which is stronger for the π - /π + ratio close to the pion production threshold. The Coulomb potential of the mesons changes the transverse momentum distribution of the π - /π + ratio significantly, though it alters only slightly the π - and π + total yields. The π - yields, especially at midrapidity or at low transverse momenta and the π - /π + ratios at low transverse momenta are shown to be sensitive probes of the density-dependent symmetry potential in dense nuclear matter. The effect of the density-dependent symmetry potential on the production of both K 0 and K + mesons is also investigated

  14. Pion correlations and calorimeter design for high energy heavy ion collisions. Progress report

    International Nuclear Information System (INIS)

    Wolf, K.L.

    1997-01-01

    Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV 208 Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered 208 Pb + Pb collisions. An updated multi-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-pion interferometry in the 1.2 A GeV Au + Au reaction, taken with full event characterization

  15. Pion and kaon correlations in high energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Wolf, K.L.

    1996-01-01

    Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV 208 Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered 208 Pb + Pb collisions. An upgraded multi-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-pion interferometry in the 1.2 A GeV Au+Au reaction, taken with full event characterization. 35 refs., 15 figs., 5 tabs

  16. Systematics of elastic scattering at high and intermediate energy

    Energy Technology Data Exchange (ETDEWEB)

    Dias De Deus, J [Instituto de Fisica e Matematica, Lisboa (Portugal); Kroll, P [Wuppertal Univ. (Gesamthochschule) (Germany, F.R.)

    1977-01-01

    A model for elastic scattering valid in the intermediate and high-energy region is proposed. The model includes three kinds of entities: the pomeron, a universal GS pomeron; the reggeons, also universal and of GS type; and the core, a low-energy central real piece required by dispersion relations. The number of free functions and parameters is rather small. The approach supports naive duality and, in general, agrees with the results of absorptive models.

  17. Relativistic generalizations of simple pion-nucleon models

    International Nuclear Information System (INIS)

    McLeod, R.J.; Ernst, D.J.

    1981-01-01

    A relativistic, partial wave N/D dispersion theory is developed for low energy pion-nucleon elastic scattering. The theory is simplified by treating crossing symmetry only to lowest order in the inverse nucleon mass. The coupling of elastic scattering to inelastic channels is included by taking the necessary inelasticity from experimental data. Three models are examined: pseudoscalar coupling of pions and nucleons, pseudovector coupling, and a model in which all intermediate antinucleons are projected out of the amplitude. The phase shifts in the dominant P 33 channel are quantitatively reproduced for P/sub lab/ 33 phase shifts. Thus a model of the pion-nucleon interaction which does not include antinucleon degrees of freedom is found to be unphysical

  18. Phenomenological model for particle production from the collisions of nucleons and pions with fissile elements at medium energies

    International Nuclear Information System (INIS)

    Alsmiller, F.S.; Alsmiller, R.G. Jr.; Gabriel, T.A.; Lillie, R.A.; Barish, J.

    1981-03-01

    A fission channel has been added to the intranuclear-cascade-evaporation model of nuclear reactions so that this model may be used to obtain the differential particle production data that are needed to study the transport of medium-energy nucleons and pions through fissionable material. The earlier work of Hahn and Bertini on the incorporation of fission-evaporation competition into the intranuclear-cascade-evaporation model has been retained, and the statistical model of fission has been utilized to predict particle production from the fission process. Approximate empirically derived kinetic energies and deformation energies are used in the statistical model. The calculated number of emitted neutrons and residual nuclei distributions are in reasonable agreement with experimental data, but the number of emitted neutrons at the higher incident nucleon energies (approx. > 500 MeV) are sensitive to the level density parameter used. 9 figures, 2 tables

  19. Quark bag coupling to finite size pions

    International Nuclear Information System (INIS)

    De Kam, J.; Pirner, H.J.

    1982-01-01

    A standard approximation in theories of quark bags coupled to a pion field is to treat the pion as an elementary field ignoring its substructure and finite size. A difficulty associated with these treatments in the lack of stability of the quark bag due to the rapid increase of the pion pressure on the bad as the bag size diminishes. We investigate the effects of the finite size of the qanti q pion on the pion quark bag coupling by means of a simple nonlocal pion quark interaction. With this amendment the pion pressure on the bag vanishes if the bag size goes to zero. No stability problems are encountered in this description. Furthermore, for extended pions, no longer a maximum is set to the bag parameter B. Therefore 'little bag' solutions may be found provided that B is large enough. We also discuss the possibility of a second minimum in the bag energy function. (orig.)

  20. On spallation and fragmentation of heavy ions at intermediate energies

    International Nuclear Information System (INIS)

    Musulmanbekov, G.; Al-Haidary, A.

    2002-01-01

    A new code for simulation of spallation and (multi)fragmentation of nuclei in proton and nucleus induced collisions at intermediate and high energies is developed. The code is a combination of modified intranuclear cascade model with traditional fission - evaporation part and multifragmentation part based on lattice representation of nuclear structure and percolation approach. The production of s-wave resonances and formation time concept included into standard intranuclear cascade code provides correct calculation of excitation energy of residues. This modified cascade code served as a bridge between low and high energy model descriptions of nucleus-nucleus collisions. A good agreement with experiments has been obtained for multiparticle production at intermediate and relatively high energies. Nuclear structure of colliding nuclei is represented as face centered cubic lattice. This representation, being isomorphic to the shell model of nuclear structure, allows to apply percolation approach for nuclear fragmentation. The offered percolation model includes both site and bond percolation. Broken sites represent holes left by nucleons knocked out at cascade state. Therefore, in the first cascade stage mutual rescattering of the colliding nuclei results in knocking some nucleons out of them. After this fast stage paltrily destruct and excited residues remain. On the second stage residual nuclei either evaporate nucleons and light nuclei up to alpha-particles or fragment into pieces with intermediate masses. The choice depends on residue's destruction degree. At low excitation energy and small destruction of the residue the evaporation and fission mechanisms are preferable. The more excitation energy and destruction the more probability of (multi)fragmentation process. Moreover, the more destruction degree of the residual the more the site percolation probability. It is concluded, that at low and intermediate excitation energies the fragmentation of nuclei is slow

  1. Neutral pion cross section and spin asymmetries at intermediate pseudorapidity in polarized proton collisions at root s=200 GeV

    Czech Academy of Sciences Publication Activity Database

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C.; Aparin, A. A.; Arkhipkin, D.; Barnovská, Zuzana; Bielčík, J.; Bielčíková, Jana; Chaloupka, P.; Pachr, M.; Rusňák, Jan; Šumbera, Michal; Tlustý, David; Vértési, Robert

    2014-01-01

    Roč. 89, č. 1 (2014), 012001 ISSN 1550-7998 R&D Projects: GA ČR GA13-20841S Institutional support: RVO:61389005 Keywords : pions production * transverse momentum * STAR Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 4.643, year: 2014

  2. Isospin effects in intermediate energy heavy ion collision

    International Nuclear Information System (INIS)

    Liu Jianye; Zuo Wei; Yang Yanfang; Zhao Qiang; Guo Wenjun

    2001-01-01

    Based on the achievements for the intermediate energy heavy ion collision in authors' recent work and the progresses in the world, the isospin effects and the dependence of the entrance channel conditions on them in the intermediate energy heavy ion collisions were introduced, analysed and commended. From the calculation results by using isospin dependence quantum molecular dynamics, it is clear to see that the nuclear stopping power strongly depends on the in-medium isospin dependence nucleon-nucleon cross section and weakly on the symmetry potential in the energy region from about Fermi energy to 150 MeV/u and the intermediate mass fragment multiplicity also sensitively depends on the in-medium isospin dependent nucleon-nucleon cross section and weakly on the symmetry potential in a selected energy region. But the preequilibrium emission neutron-proton ratio is quite contrary, it sensitively depends on the symmetry potential and weakly on the in-medium isospin dependent nucleon-nucleon cross section. In addition to the nuclear stopping sensitively depending on the beam energy, impact parameter and the mass of colliding system and weakly on the neutron-proton ratio of the colliding systems with about the same mass, the preequilibrium emission neutron-neutron ratio sensitively depends on the beam energy and the neutron-proton ratio of colliding system, but weakly on the impact parameter. From above results it is proposed that the nuclear stopping is a new probe to extract the information on the in-medium isospin dependence nucleon-nucleon cross section in energy region from about Fermi energy to 150 MeV/u and the preequilibrium emission neutron-proton ratio is a good probe for extracting the information about the symmetry potential from the lower energy to about 150 MeV/u

  3. The calculation of the contributions to low energy e+H2 scattering from sigma u+ and pion u symmetries using the Kohn variational method

    International Nuclear Information System (INIS)

    Armour, E.A.G.; Baker, D.J.; Plummer, M.

    1990-01-01

    Above incident energies of about 2 eV, the contribution to the total cross section in positron+H2 scattering from the sigma g+ symmetry is insufficient to account for the experimental value. Calculations carried out of the lowest partial waves of sigma u+ symmetry and Pion u symmetry using the Kohn variational method are described. The contributions to the total cross section from the two equivalent partial waves of Pion u symmetry significantly reduce the discrepancy with experiment up to incident energies of 4 to 5 eV. Comparisons are made with recent R-matrix calculations performed by Danby and Tennyson

  4. Determination of amplitudes in neutral pion photoproduction and comparison with partial waves analysis in the energy range of 1.3 to 2.1 GeV

    International Nuclear Information System (INIS)

    Forozani, G.

    2004-01-01

    The magnitude of four independent amplitudes are obtained pion photoproduction in the energy range of 1300 to 2100 MeV incident photon. Different cross section and three polarization parameters are required for such amplitudes reconstruction at different pion scattering angles. Results of the direct amplitudes reconstruction have been compared with the solution of partial wave analysis SM95 and SM00K at all energies. This analysis indicates that we have a fair agreement between the present work and the results of partial wave analysis at many angles

  5. Determination of amplitudes in neutral pion photoproduction and comparison with partial waves analysis in the energy range of 1.3 to 2.1 GeV

    International Nuclear Information System (INIS)

    Forozani, G.

    2004-01-01

    The magnitude of four independent amplitudes are obtained in neutral pion photoproduction in the energy range of 1300 to 2100 MeV incident photon. Differential gross section and three polarization parameters are required for such amplitudes reconstruction at different pion scattering angles. Results of the direct amplitudes reconstruction have been compared with the solution of partial wave analysis SM95 and SM00K at all energies. This analysis indicates that we have a fair agreement between the present work and the results of partial wave analysis at meny angles (Author)

  6. The calculation of the contributions to low energy e+H2 scattering from sigma u+ and Pion u symmetries using the Kohn variational method

    Science.gov (United States)

    Armour, E. A. G.; Baker, D. J.; Plummer, M.

    1990-01-01

    Above incident energies of about 2 eV, the contribution to the total cross section in positron+H2 scattering from the sigma g+ symmetry is insufficient to account for the experimental value. Calculations carried out of the lowest partial waves of sigma u+ symmetry and Pion u symmetry using the Kohn variational method are described. The contributions to the total cross section from the two equivalent partial waves of Pion u symmetry significantly reduce the discrepancy with experiment up to incident energies of 4 to 5 eV. Comparisons are made with recent R-matrix calculations performed by Danby and Tennyson.

  7. Role of delta excitations in pion-, photon- and nucleon-nucleus reactions studied with microscopic models

    International Nuclear Information System (INIS)

    Engel, A.

    1995-01-01

    Delta excitation plays a prominent role in intermediate heavy reactions. In this paper, comment is made on the calculations done for pion-, photon- and nucleon-nucleus reactions using the Boltzmann-Uehling-Uhlenbeck (BUU) model and the antisymmetrized molecular dynamics (AMD) model. First, it is recalled how to include delta degrees in microscopic models in general. Then, the comparison of the microscopic calculation performed by the author with the experimental data is presented. Deltas in microscopic models are discussed. Pion-nucleus reactions have been studied since pion beams became available, especially for exploring the delta resonance in a nuclear medium. The dependence of pion absorption cross section on incident pion energy is shown. The photon-induced pion production in the resonance energy region was studied with the BUU model. The calculated results of neutral pion photo-production are shown. In both inelastic proton scattering and (p,n) charge exchange reaction, the excitation of delta resonance can be observed clearly in the experimental data. The results of the AMD calculation for 12 C(p,p') reaction are shown. (K.I.)

  8. Angular correlations and fragmentation in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Kristiansson, Anders.

    1990-05-01

    Intermediate energy heavy-ion collisions have been studied from 35 A MeV up to 94 A MeV at various accelerators. Angular correlations between light particles and detection of projectile- and target-fragments have been used to investigate the reaction mechanisms in this transition region between low- and high energy. An excess of correlations is observed in the particle-particle elastic scattering plane. This excess increases with particle mass and can be understood in terms of momentum conservation. The fragmentation measurements gives an indication that both energy and momentum transfer to the spectator volumes does occur. (author)

  9. Nuclear transparencies from photoinduced pion production

    Energy Technology Data Exchange (ETDEWEB)

    W. Cosyn; M.C. Martinez; J. Ryckebusch; B. Van Overmeire

    2006-12-01

    We present a relativistic and cross-section factorized framework for computing nuclear transparencies extracted from A({gamma}, {pi} N) reactions at intermediate energies. The proposed quantum mechanical model adopts a relativistic extension to the multiple-scattering Glauber approximation to account for the final state interactions of the ejected nucleon and pion. The theoretical predictions are compared against the experimental {sup 4}He({gamma},p {pi}{sup -}) data from Jefferson Lab. For those data, our results show no conclusive evidence for the onset of mechanisms related to color transparency.

  10. Chiral Dynamics in Pion-Photon Reactions Habilitation

    CERN Document Server

    Friedrich, Jan Michael

    As the lightest particle of the strong force, the pion plays a central role in the field of strong interactions, and understanding its properties is of prime relevance for understanding the strong interaction in general. The low-energy behaviour of pions is of particular interest. Although the quark-gluon substructure and their quantum chromodynamics is not apparent then, this specific inner structure causes the presence of approximate symmetries in pion-pion interactions and in pion decays, which gives rise to the systematic description of processes involving pions in terms of few low-energy constants. Specifically, the chiral symmetry and its spontaneous and explicit breaking, treated in chiral perturbation theory (ChPT), leads to firm predictions for low-energy properties of the pion. To those belong the electromagnetic polarisabilities of the pion, describing the leading-order structure effect in pion Compton scattering. The research presented in this work is concerned with the interaction of pions and ph...

  11. Measurement of inverse pion photoproduction at energies spanning the N(1440) resonance

    International Nuclear Information System (INIS)

    Shafi, A.; Strakovsky, I.I.; Briscoe, W.J.; Arndt, R.A.; Bennhold, C.; Workman, R.L.; Prakhov, S.; Nefkens, B.M.K.; Clajus, M.; Marusic, A.; McDonald, S.; Phaisangittisakul, N.; Price, J.W.; Tippens, W.B.; Allgower, C.E.; Spinka, H.; Bekrenev, V.; Kulbardis, A.; Kozlenko, N.; Kruglov, S.

    2004-01-01

    Differential cross sections for the process π - p→γn have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E γ for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the γn multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations

  12. Transport code and nuclear data in intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Akira; Odama, Naomitsu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Maekawa, F.; Ueki, K.; Kosaka, K.; Oyama, Y.

    1998-11-01

    We briefly reviewed the problems of intermediate energy nuclear data file and transport codes in connection with processing of the data. This is a summary of our group in the task force on JENDL High Energy File Integral Evaluation (JHEFIE). In this article we stress the necessity of the production of intermediate evaluated nuclear data file up to 3 GeV for the application of accelerator driven transmutation (ADT) system. And also we state the necessity of having our own transport code system to calculate the radiation fields using these evaluated files from the strategic points of view to keep our development of the ADT technology completely free from other conditions outside of our own such as imported codes and data with poor maintenance or unknown accuracy. (author)

  13. Transport code and nuclear data in intermediate energy region

    International Nuclear Information System (INIS)

    Hasegawa, Akira; Odama, Naomitsu; Maekawa, F.; Ueki, K.; Kosaka, K.; Oyama, Y.

    1998-01-01

    We briefly reviewed the problems of intermediate energy nuclear data file and transport codes in connection with processing of the data. This is a summary of our group in the task force on JENDL High Energy File Integral Evaluation (JHEFIE). In this article we stress the necessity of the production of intermediate evaluated nuclear data file up to 3 GeV for the application of accelerator driven transmutation (ADT) system. And also we state the necessity of having our own transport code system to calculate the radiation fields using these evaluated files from the strategic points of view to keep our development of the ADT technology completely free from other conditions outside of our own such as imported codes and data with poor maintenance or unknown accuracy. (author)

  14. ''Super-radiant'' states in intermediate energy nuclear physics

    International Nuclear Information System (INIS)

    Auerbach, N.

    1994-01-01

    A ''super-radiant'' state emerges when, under certain conditions, one or a few ''internal'' states acquire a large collective decay width due to the coupling to one or a few ''external'' decay channels. The rest of the internal states are ''stripped'' of their decay width and become long lived quasistationary states. The essentials of such mechanism and its possible role in intermediate energy nuclear physics are discussed in this work

  15. Intermediate energy heavy ion reactions. A program for CELSIUS

    International Nuclear Information System (INIS)

    Jakobsson, B.

    1986-02-01

    The accelerator system under construction in Uppsala with the ECR-source + the K equals 200 synchrocyclotron + the CELSIUS synchrotron ring for storage, cooling and acceleration opens up possibilities for a very fruitful heavy ion physics program. Some recently obtained results and some recent ideas on intermediate energy reactions are discussed and speculations are made about some experiments where the unconventional qualities of CELSIUS beams could be utilized. (author)

  16. Pion production in nucleus--nucleus collisions

    International Nuclear Information System (INIS)

    Schroeder, L.S.

    1975-06-01

    Current work on pion production in high-energy nucleus-nucleus collisions is reviewed. The majority of existing data are of the inclusive variety in which a single final state pion is detected. Experimental data are compared and their possible contributions to obtaining new information on nuclear structure is discussed. Various models which attempt to explain the observed single-inclusive-pion spectra either on the basis of a nucleon-nucleus interaction in which Fermi motion is included or on some type of cooperative model are examined. Other areas of interest involving pion production include tests of charge symmetry and pion multiplicities. (9 figures, 1 table) (U.S.)

  17. Needs for experiment and theory in intermediate energy reactions

    International Nuclear Information System (INIS)

    Blann, M.

    1991-01-01

    We summarize several reasons intermediate energy data are needed in both basic and applied science. The status of the data base at energies up to 2 GeV is cursorily reviewed. Experimental excitation functions, single and double differential cross sections are compared with predictions of the nuclear model code ALICE. The strengths and weaknesses of the code to reproduce data are summarized. Opinions are given as to areas where data are too few or totally lacking, yet are needed for the verification of models and theories. (author). 25 refs, 22 figs

  18. Intermediate energy nuclear physics (Task C) and charge exchange reactions (Task W). Technical progress report, October 1, 1985-October 1, 1986

    International Nuclear Information System (INIS)

    Kraushaar, J.J.

    1986-10-01

    This report describes the experimental work in intermediate energy research carried out over the past year at the University of Colorado. The experimental program is very broad in nature, ranging from investigations in pion-nucleus interactions, nucleon charge exchange, inelastic electron scattering, and nucleon transfer reactions. The experiments were largely carried out at the Los Alamos Meson Physics Facility, but important programs were conducted at the Tri-University Meson Facility at the University of British Columbia, the Indiana University Cyclotron Facility and Netherlands Institute for Nuclear Physics Research (NIKHEF-K)

  19. Fluctuations in transverse energy and multiplicity, energy densities, and neutral pion spectra in nucleus-nucleus collissions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    Plasil, F.; Albrecht, R.; Awes, T.C.

    1989-01-01

    The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The quantity most crucial to the probability of QGP formation is the thermalized energy density attained during the heavy-ion reaction. The amount of energy radiated transverse to the beam direction is the experimental quantity which is believed to be a measure of the amount of energy deposition in the reaction, and hence to reflect the energy density attained. In this presentation we consider the systematics of transverse energy production at CERN SPS energies, and we use the results to make estimates, under various assumptions, of attained energy densities. Measurements of direct photons and lepton pairs are considered to be among the most promising methods for studies of the QGP. In contrast to hadrons, direct photons are not expected to undergo any interactions after their creation. The WA80 collaboration has undertaken the measurement of direct photons, which is a difficult task due to the presence of a high background of photons from the decay of neutral pions. The π 0 spectra themselves, however, provide us with the opportunity to study the excited reaction zone during the hadronization phase. We present here measurements of neutral pions produced in 16 O + Au collisions at 200 GeV/nucleon. 22 refs., 11 figs

  20. Radiation quality of beams of negative pions

    International Nuclear Information System (INIS)

    Dicello, J.F.; Brenner, D.J.

    1981-01-01

    As a negative pion stops in tissue, it attaches itself to an adjacent atom to form a mesonic atom. Subsequently, the wave function of the pion interacts with that of the nucleus and the pion is absorbed. Because the energy associated with the rest mass of the pion is greater than the separation energy of the nuclear particles, the nucleus disintegrates (pion star). In tissue, approximately 40 MeV goes into overcoming the binding energies; 20 MeV goes into kinetic energy of charged particles; 80 MeV goes into kinetic energy of neutrons. In cases where biological studies are performed with beams of negative pions, as much as 20% of the total absorbed dose in the treatment volume and about 50% of the high-LET dose (> 100 keV/μm) can result from neutrons. The degree of biological response and the variation of that response throughout the treatment volume can be altered by the neutron dose

  1. The radial shapes of intermediate energy microscopic optical potentials

    International Nuclear Information System (INIS)

    Shen Qingbiao; Wang Chang; Tian Ye; Zhuo Yizhong

    1984-01-01

    The radial shapes of intermediate energy proton microscopic optical potentials of 40 Ca are calculated with nuclear matter approach by Skyrme interactions. The calculated results show that the real central potential in central region of nucleus changes from attractive to repulsive when the energy of incident nucleon is above 150 MeV and appears apparently a 'wine-bottle-bottom' shape in the transition energy region (from 150 MeV to 300 MeV). This tendency is consistent with empirical optical potential obtained through fitting experiments and microscopic optical potential calculated with relativistic mean field theory as well as with the BHF theory. The calculated imaginary part of the microscopic optical potential changes from the dominant surface absorption into the volume absorption and its absolute value become larger as energy increases. The effects of Skyrme force parameters to the radial shape of the calculated microscopic optical potential are analysed in detail

  2. Radiative corrections to the charged pion-pair production process {pi}{sup -}{gamma} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -} at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, N.; Petschauer, S. [Technische Universitaet Muenchen, Physik-Department T39, Garching (Germany)

    2013-12-15

    We calculate the one-photon loop radiative corrections to the charged pion-pair production process {pi}{sup -}{gamma} {yields} {pi}{sup +}{pi}{sup -}{pi}{sup -}. In the low-energy region this reaction is governed by the chiral pion-pion interaction. The pertinent set of 42 irreducible photon-loop diagrams is calculated by using the package FeynCalc. Electromagnetic counterterms with two independent low-energy constants k{sub 1} and k{sub 2} are included in order to remove the ultraviolet divergences generated by the photon loops. Infrared finiteness of the virtual radiative corrections is achieved by including soft photon radiation below an energy cut-off {Lambda}. The purely electromagnetic interaction of the charged pions mediated by one-photon exchange is also taken into account. The radiative corrections to the total cross section (in the isospin limit) vary between +10% close to threshold and about -1% at a center-of-mass energy of 7m{sub {pi}}. The largest contribution comes from the simple one-photon exchange. Radiative corrections to the {pi}{sup +}{pi}{sup -} and {pi}{sup -}{pi}{sup -} mass spectra are studied as well. The Coulomb singularity of the final-state interaction produces a kink in the dipion mass spectra. The virtual radiative corrections to elastic {pi}{sup -}{pi}{sup -} scattering are derived additionally. (orig.)

  3. Physics of the pion liquid

    International Nuclear Information System (INIS)

    Shuryak, E.V.

    1990-01-01

    Excited hadronic matter in the temperature interval T = 100-200 MeV is not an ideal pion gas, but ratehr a liquid, in which attractive interaction among particles plays an important role. Pion dispersion curve is in this case essentially modified by a kind of collective momentum-dependent potential, which becomes important as the quasipion comes to the boundary of the system. The author shows that these effects can provide an explanation for a number of recent experimental puzzles, in particular, for the observed copious production of soft pions and soft photons in high energy hadronic reactions

  4. Physics of the pion liquid

    International Nuclear Information System (INIS)

    Shuryak, E.V.

    1990-04-01

    Excited hadronic matter in the temperature interval T = 100--200 MeV is not an ideal pion gas, but rather a liquid, in which attractive interaction among particles plays an important role. Pion dispersion curve is in this case essentially modified by a kind of collective momentum-dependent potential, which becomes important as the ''quasipion'' comes to the boundary of the system. We show that effects can provide and explanation for a number of recent experimental puzzles, in particular, for the observed copious production of soft pions and soft photons in high energy hadronic reactions. 31 refs., 13 figs

  5. Real and virtual pions in nuclei

    International Nuclear Information System (INIS)

    Giraud, N.

    1984-02-01

    The thesis first part is concerned with physical pion interaction with deuton, studied in a three-body problem frame. The elastic cross-section in the energy range near the resonance (3-3), has been deduced taking in account the pion virtual absorption. The second part is concerned with virtual pion in nuclei. In particular the virtual pion cloud around the nucleus has been studied and the effective constant coupling pion-nucleus has been deduced. This one is strongly reduced by polorazation effects of the nuclear medium (essentially by virtual excitation of the Δ isobar), in relation to its value for free nucleon collection. In the frame of the same polarization model, the pion field inside the nucleus has been studied also. This field is lowered for small momentum transfer. It is increased for large momentum transfer. This last phenomenon corresponds to critical opalescence related to phase transition of pion condensation [fr

  6. Pion nucleus optical potential

    International Nuclear Information System (INIS)

    Kam, J. de.

    1981-01-01

    The main goal of the investigations, presented is to establish the contributions to the optical potential, coming from scattering processes which involve 1p-1h nuclear states in the intermediate scattering system. The effects of the Pauli principle corrections and the binding corrections are studied in detail. A phenomenological study of pion absorption effects is also presented. The calculations all concern π- 4 He scattering. The simplicity of the 4 He structure makes the π- 4 He system quite an ideal tool for studying the reaction mechanism. (Auth.)

  7. MCNP6 fragmentation of light nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Mashnik, Stepan G., E-mail: mashnik@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Kerby, Leslie M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); University of Idaho, Moscow, ID 83844 (United States)

    2014-11-11

    Fragmentation reactions induced on light target nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the latest Los Alamos Monte Carlo transport code MCNP6 and with its cascade-exciton model (CEM) and Los Alamos version of the quark-gluon string model (LAQGSM) event generators, version 03.03, used as stand-alone codes. Such reactions are involved in different applications, like cosmic-ray-induced single event upsets (SEU's), radiation protection, and cancer therapy with proton and ion beams, among others; therefore, it is important that MCNP6 simulates them as well as possible. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. Both CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to {sup 4}He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.

  8. Intermediate energy semileptonic probes of the hadronic neutral current

    International Nuclear Information System (INIS)

    Musolf, M.J.; Donnelly, T.W.; Dubach, J.; Beise, E.J.; Maryland Univ., College Park, MD

    1993-06-01

    The present status and future prospects of intermediate-energy semileptonic neutral current studies are reviewed. Possibilities for using parity-violating electron scattering from nucleons and nuclei to study hadron structure and nuclear dynamics are emphasized, with particular attention paid to probes of strangeness content in the nucleon. Connections are drawn between such studies and tests of the electroweak gauge theory using electron or neutrino scattering. Outstanding theoretical issues in the interpretation of semileptonic neutral current measurements are highlighted and the prospects for undertaking parity-violating electron or neutrino scattering experiments in the near future are surveyed

  9. Scaling of anisotropy flows in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Ma, Y.G.; Yan, T.Z.; Cai, X.Z.; Chen, J.G.; Fang, D.Q.; Guo, W.; Liu, G.H.; Ma, C.W.; Ma, E.J.; Shen, W.Q.; Shi, Y.; Su, Q.M.; Tian, W.D.; Wang, H.W.; Wang, K.

    2007-01-01

    Anisotropic flows (v 1 , v 2 and v 4 ) of light nuclear clusters are studied by a nucleonic transport model in intermediate energy heavy ion collisions. The number-of-nucleon scalings of the directed flow (v 1 ) and elliptic flow (v 2 ) are demonstrated for light nuclear clusters. Moreover, the ratios of v 4 /v 2 2 of nuclear clusters show a constant value of 1/2 regardless of the transverse momentum. The above phenomena can be understood by the coalescence mechanism in nucleonic level and are worthy to be explored in experiments

  10. Spin observables in proton-neutron scattering at intermediate energy

    International Nuclear Information System (INIS)

    Spinka, H.

    1986-05-01

    A summary of np elastic scattering spin measurements at intermediate energy is given. Preliminary results from a LAMPF experiment to measure free neutron-proton elastic scattering spin-spin correlation parameters are presented. A longitudinally polarized proton target was used. These measurements are part of a program to determine the neutron-proton amplitudes in a model independent fashion at 500, 650, and 800 MeV. Some new proton-proton total cross sections in pure helicity states (Δσ/sub L/(pp)) near 3 GeV/c are also given. 37 refs., 2 figs

  11. Electron capture in ion-molecule collisions at intermediate energy

    International Nuclear Information System (INIS)

    Kumura, M.

    1986-01-01

    Recent progress of theoretical charge transfer study in ion-molecule collisions at the intermediate energy is reviewed. Concept of close and distant collisions obtained from extensive ion-atom collision studies is identified so that it can be utilized to model two distinct collision processes. For a close collision, explicit representation of the whole collision complex is necessary to describe collision dynamics correctly, while a model potential approach for molecule is appropriate for a distant collision. It is shown that these two distinct models are indeed capable of reproducing experimental charge transfer cross sections. Some remarks for further theoretical study of ion-molecule collisions are also given. 21 refs., 8 figs

  12. An analytic distorted wave approximation for intermediate energy proton scattering

    International Nuclear Information System (INIS)

    Di Marzio, F.; Amos, K.

    1982-01-01

    An analytic Distorted Wave approximation has been developed for use in analyses of intermediate energy proton inelastic scattering from nuclei. Applications are made to analyse 402 and 800 MeV data from the isoscalar and isovector 1 + and 2 + states in 12 C and to the 800 MeV data from the excitation of the 2 - (8.88MeV) state in 16 O. Comparisons of predictions made using different model two-nucleon t-matrices and different models of nuclear structure are given

  13. Production of intermediate energy beams by high speed rotors

    International Nuclear Information System (INIS)

    Nutt, C.W.; Bale, T.J.; Cosgrove, P.; Kirby, M.J.

    1975-01-01

    A rotor apparatus intended for the study of gas/surface interaction processes is presently nearing completion. The carbon fiber rotors under consideration are constructed with shapes derived from long thin cylindrical rods oriented with the longest axis in a horizontal plane, and spun in a horizontal plane about an axis which is perpendicular to the long axis and passes through the mid-point of the cylinder. The beam formation processes are discussed and rotor diagrams presented. Performance of these types of high speed rotor show them to have a very important future as sources of intermediate energy molecular beams

  14. Pion inelastic scattering, pion photoproduction and inelastic electron scattering on light nuclei

    International Nuclear Information System (INIS)

    Ehramzhyan, R.A.

    1985-01-01

    Partial transitions in pion photoproduction reaction on 6 Li, 10 B, 12 C nuclei are considered. Particular stress is paied to simultaneous analysis both of (γ, π) ad (e, e'), (π, π') reactions. Such analysis is concretely ixemplified with the use of both phenomenological and microscopic approaches. Microscopic analysis is shown to give correct representation of reaction mechanism (γ, π), (e, e') and (π, π') at intermediate energies. Spin-isospin dipole resonances in 1p-shell nuclei are considered. It is shown that nuclear system excitation spectrum gross-structure is a result of resonance configuration splitting

  15. Connected and disconnected contractions in pion-pion scattering

    Science.gov (United States)

    Acharya, Neramballi Ripunjay; Guo, Feng-Kun; Meißner, Ulf-G.; Seng, Chien-Yeah

    2017-09-01

    We show that the interplay of chiral effective field theory and lattice QCD can be used in the evaluation of so-called disconnected diagrams, which appear in the study of the isoscalar and isovector channels of pion-pion scattering and have long been a major challenge for the lattice community. By means of partially-quenched chiral perturbation theory, we distinguish and analyze the effects from different types of contraction diagrams to the pion-pion scattering amplitude, including its scattering lengths and the energy-dependence of its imaginary part. Our results may be used to test the current degree of accuracy of lattice calculation in the handling of disconnected diagrams, as well as to set criteria for the future improvement of relevant lattice computational techniques that may play a critical role in the study of other interesting QCD matrix elements.

  16. Monte Carlo calculations for intermediate-energy standard neutron field

    International Nuclear Information System (INIS)

    Joneja, O.P.; Subbukutty, K.; Iyengar, S.B.D.; Navalkar, M.P.

    Intermediate-Energy Standard Neutron Field (ISNF) which produces a well characterised spectrum in the energy range of interest for fast reactors including breeders, has been set up at NBS using thin enriched 235 U fission sources. A proposal has been made for setting up a similar facility at BARC using however, easily available natural U instead of enriched U sources, to start with. In order to simulate the neutronics of such a facility Monte Carlo method of calculations has been adopted and developed. The results of these calculations have been compared with those of NBS and it is found that there may be a maximum difference of 10% in spectrum characteristics for the two cases of using thick and thin fission sources. (K.B.)

  17. Macroscopic/microscopic simulation of nuclear reactions at intermediate energies

    International Nuclear Information System (INIS)

    Lacroix, D.; Van Lauwe, A.; Durand, D.

    2003-01-01

    An event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedicated to the description of nuclear collisions in the intermediate energy range is presented. The model simulates events for reactions close to the fusion barrier (5-10 MeV/A) up to higher energy (100 MeV/A) and it gives access to the phase-space explored during the collision. The development of HIPSE has been largely influenced by experimental observations. We have separated the reaction into 4 steps: contact, fragment formation, chemical freeze-out, and in-flight deexcitation. HIPSE will be useful for a study of various mechanisms such as neck fragmentation or multi-fragmentation

  18. Dynamical and statistical aspects of intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Knoll, J.

    1987-01-01

    The lectures presented deal with three different topics relevant for the discussion of nuclear collisions at medium to high energies. The first lecture concerns a subject of general interest, the description of statistical systems and their dynamics by the concept of missing information. If presents an excellent scope to formulate statistical theories in such a way that they carefully keep track of the known (relevant) information while maximizing the ignorance about the irrelevant, unknown information. The last two lectures deal with quite actual questions of intermediate energy heavy-ion collisions. These are the multi-fragmentation dynamics of highly excited nuclear systems, and the so called subthreshold particle production. All three subjects are self-contained, and can be read without the knowledge about the other ones. (orig.)

  19. Nuclear data evaluation at intermediate energies: An introduction

    International Nuclear Information System (INIS)

    Koning, A.J.

    2001-01-01

    An outline is presented of the status of nuclear data evaluation for intermediate energies. Our specific contribution to the field concerns neutron and proton transport data libraries, for energies below about 150 MeV. The evaluated data are calculated and stored in ENDF6-format with the computer codes ECIS96, GNASH and MINGUS. New phenomenological optical model potentials up to 200 MeV are presented and we illustrate the library production with a short outline of the other employed physical methods. The calculated results are compared with the available experimental data. A 68 MeV neutron transmission experiment on iron has been analyzed with MCNPX using the Los Alamos LA150 neutron data library, the ECN/BRC 150 MeV neutron data library and with the intranuclear cascade code LAHET. The clear improvement by using the data libraries is confirmed. (author)

  20. Theoretical and computational studies in intermediate energy nuclear physics

    International Nuclear Information System (INIS)

    Elster, C.

    1993-08-01

    The research includes applications of many-body scattering theory to nuclear systems and studies of few-body systems described by effective hadronic field theories. Progress was made in bringing all first-order effects into the nonrelativistic elastic nucleon-nucleus scattering in a consistent fashion. This work is directed towards completely and reliably calculating the first-order term in a Watson expansion including a modification through the nulear medium. The research effort in few-body physics was concentrated on nucleon-nucleon (NN) scattering below pion production threshold, where recent measurements indicated that the backward-angle neutron-proton (np) differential cross section may show sensitivity to the size of the pion-nucleon coupling constant

  1. Intermediate evaluation of USAID/Cairo energy policy planning project

    Energy Technology Data Exchange (ETDEWEB)

    Wilbanks, T.J.; Wright, S.B. (Oak Ridge National Lab., TN (United States)); Barron, W.F. (Hong Kong Univ. (Hong Kong)); Kamel, A.M. (Ain Shams Univ., Cairo (Egypt)); Santiago, H.T. (USDOE, Washington, DC (United States))

    1992-01-01

    Three years ago, a team from the Oak Ridge National Laboratory and the Oak Ridge Associated Universities, supplemented by an expert from the US Department of Energy and a senior Egyptian energy professional, carried out what was termed an intermediate evaluation'' of a major energy policy project in Egypt. Supported by USAID/Cairo, the project had concentrated on developing and strengthening an Organization for Energy Planning (OEP) within the Government of India, and it was actually scheduled to end less than a year after this evaluation. The evaluation was submitted to USAID/Cairo and circulated elsewhere in the US Agency for International Development and the Government of Egypt as an internal report. Over the next several years, the USAID energy planning project ended and the functions performed by OEP were merged with planning capabilities in the electric power sector. Now that the major issues addressed by the evaluation report have been resolved, we are making it available to a broader audience as a contribution to the general literature on development project evaluation and institution-building.

  2. Intermediate evaluation of USAID/Cairo energy policy planning project

    Energy Technology Data Exchange (ETDEWEB)

    Wilbanks, T.J.; Wright, S.B. [Oak Ridge National Lab., TN (United States); Barron, W.F. [Hong Kong Univ. (Hong Kong); Kamel, A.M. [Ain Shams Univ., Cairo (Egypt); Santiago, H.T. [USDOE, Washington, DC (United States)

    1992-09-01

    Three years ago, a team from the Oak Ridge National Laboratory and the Oak Ridge Associated Universities, supplemented by an expert from the US Department of Energy and a senior Egyptian energy professional, carried out what was termed an ``intermediate evaluation`` of a major energy policy project in Egypt. Supported by USAID/Cairo, the project had concentrated on developing and strengthening an Organization for Energy Planning (OEP) within the Government of India, and it was actually scheduled to end less than a year after this evaluation. The evaluation was submitted to USAID/Cairo and circulated elsewhere in the US Agency for International Development and the Government of Egypt as an internal report. Over the next several years, the USAID energy planning project ended and the functions performed by OEP were merged with planning capabilities in the electric power sector. Now that the major issues addressed by the evaluation report have been resolved, we are making it available to a broader audience as a contribution to the general literature on development project evaluation and institution-building.

  3. International codes and model intercomparison for intermediate energy activation yields

    International Nuclear Information System (INIS)

    Rolf, M.; Nagel, P.

    1997-01-01

    The motivation for this intercomparison came from data needs of accelerator-based waste transmutation, energy amplification and medical therapy. The aim of this exercise is to determine the degree of reliability of current nuclear reaction models and codes when calculating activation yields in the intermediate energy range up to 5000 MeV. Emphasis has been placed for a wide range of target elements ( O, Al, Fe, Co, Zr and Au). This work is mainly based on calculation of (P,xPyN) integral cross section for incident proton. A qualitative description of some of the nuclear models and code options employed is made. The systematics of graphical presentation of the results allows a quick quantitative measure of agreement or deviation. This code intercomparison highlights the fact that modeling calculations of energy activation yields may at best have uncertainties of a factor of two. The causes of such discrepancies are multi-factorial. Problems are encountered which are connected with the calculation of nuclear masses, binding energies, Q-values, shell effects, medium energy fission and Fermi break-up. (A.C.)

  4. Pion distribution in the nucleon

    International Nuclear Information System (INIS)

    Lee, T.-S.H.

    1989-01-01

    A model is presented for calculating the pion wave function inside the nucleon. By assuming that all pions around a core of the nucleon are in the lowest eigenstate of the system, it is shown that both the bound state and πN scattering amplitude can be consistently described by an exactly soluble model defined in the subspace spanned by the core state and the physical πN state. The parameters of the model are determined by fitting the data of the nucleon mass, πNN coupling constant and low energy πN scattering phase shifts. The model predicts that the probability of finding the pion component inside the nucleon is about 20%. The calculated πNN form factor differs significantly from the conventional monopole form. The dynamical consequences of the differences are demonstrated in a calculation of electromagnetic production of pions from the nucleon and the deuteron. 7 refs., 4 figs., 1 tab

  5. Scale of corrections to the t-pole approximation in the quasielastic knockout of pions from nucleon by high energy electrons

    CERN Document Server

    Neudachin, V G; Yudin, N P

    2002-01-01

    Investigation of the dominant role of the simplest t-pole diagrams is completed in the processes of pion electroproduction on nucleons at quasielastic knock out kinematics and electron energies of a few GeV. Competition role of pi- and rho-meson t-pole diagrams and s-pole diagram (tree diagram) is regarded. When virtual photon mass is large enough (Q sup 2 >= 2 (GeV/c) sup 2), the latter amplitude is not essential both for longitudinal (d sigma sub L /dt) and for transverse (d sigma sub T /dt) cross sections. At Q sup 2 = 0.7 (GeV/c) sup 2 in the longitudinal cross section the interference term between pion t-pole and s-pole amplitudes is still essential. Vertex functions g subrho sub N sub N (t), obtained from the cross sections of the quasielastic knockout of rho mesons and from cross section of pion photoproduction, are compared. Their discrepancy must give impulse to the development of gauge invariant theory of pion photoproduction

  6. Statistical and dynamical aspects of intermediate energy nuclear collisions

    International Nuclear Information System (INIS)

    Ghetti, R.

    1997-01-01

    Studies of intermediate energy heavy ion reactions have revealed that the probability of emitting n-fragments is reducible to the probability of emitting a single fragment through the binomial distribution. The resulting one-fragment probability shows a dependence on the thermal energy that is characteristic of statistical decay. Similarly, the charge distributions associated with n-fragment emission are reducible to the one-fragment charge distribution, and thermal scaling is observed. The reducibility equation for the n-fragment charge distribution contains a quantity with a value that starts from zero, at low transverse energies, and saturates at high transverse energies. This evolution may signal a transition from a coexistence phase to a vapour phase. In the search for a signal of liquid-gas phase transition, the appearance of intermittency is reconsidered. Percolation calculations, as well as data analysis, indicate that an intermittent-like signal appears from classes of events that do not coincide with the critical one. 232 refs

  7. Modelling interaction cross sections for intermediate and low energy ions

    International Nuclear Information System (INIS)

    Toburen, L.H.; Shinpaugh, J.L.; Justiniano, E.L.B.

    2002-01-01

    When charged particles slow in tissue they undergo electron capture and loss processes than can have profound effects on subsequent interaction cross sections. Although a large amount of data exists for the interaction of bare charged particles with atoms and molecules, few experiments have been reported for these 'dressed' particles. Projectile electrons contribute to an impact-parameter-dependent screening of the projectile charge that precludes straightforward scaling of energy loss cross sections from those of bare charged particles. The objective of this work is to develop an analytical model for the energy-loss-dependent effects of screening on differential ionisation cross sections that can be used in track structure calculations for high LET ions. As a first step a model of differential ionisation cross sections for bare ions has been combined with a simple screening model to explore cross sections for intermediate and low energy dressed ions in collisions with atomic and molecular gas targets. The model is described briefly and preliminary results compared to measured electron energy spectra. (author)

  8. Statistical and dynamical aspects of intermediate energy nuclear collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ghetti, R.

    1997-01-01

    Studies of intermediate energy heavy ion reactions have revealed that the probability of emitting n-fragments is reducible to the probability of emitting a single fragment through the binomial distribution. The resulting one-fragment probability shows a dependence on the thermal energy that is characteristic of statistical decay. Similarly, the charge distributions associated with n-fragment emission are reducible to the one-fragment charge distribution, and thermal scaling is observed. The reducibility equation for the n-fragment charge distribution contains a quantity with a value that starts from zero, at low transverse energies, and saturates at high transverse energies. This evolution may signal a transition from a coexistence phase to a vapour phase. In the search for a signal of liquid-gas phase transition, the appearance of intermittency is reconsidered. Percolation calculations, as well as data analysis, indicate that an intermittent-like signal appears from classes of events that do not coincide with the critical one. 232 refs.

  9. Proceedings of the Workshop on Program Options in Intermediate-Energy Physics. Keynote address: New directions in intermediate-energy nuclear physics

    International Nuclear Information System (INIS)

    Brown, G.E.

    1980-05-01

    This report presents the keynote address given by G.E. Brown at a LASL colloquium on August 21, 1979, for the Workshop on Program Options in Intermediate-Energy Physics. Professor Brown reviewed major topics of interest in intermediate-energy nuclear physics and suggested experimental approaches that might be most productive in the near future. 22 figures

  10. Spin effects in intermediate-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Xu Jun; Li Baoan; Xia Yin; Shen Wenqing

    2014-01-01

    In this paper, we report and extend our recent work where the nucleon spin-orbit interaction and its spin degree of freedom were introduced explicitly for the first time in the isospin-dependent Boltzmann-Uehling-Uhlenbeck transport model for heavy-ion reactions. Despite of the significant cancellation of the time-even and time-odd spin-related mean-field potentials from the spin-orbit interaction,an appreciable local spin polarization is observed in heavy-ion collisions at intermediate energies because of the dominating role of the time-odd terms. It is also found that the spin up-down differential transverse flow in heavy-ion collisions is a useful probe of the strength, density dependence, and isospin dependence of the in-medium spin-orbit interaction, and its magnitude is still considerable even at smaller systems. (authors)

  11. Nucleon charge-exchange reactions at intermediate energy

    International Nuclear Information System (INIS)

    Alford, W.P.; Spicer, B.M.

    1997-01-01

    An historical review of the development of ideas pertaining to Gamow-Teller giant resonances is given, and a description of the emergence of techniques for the study of charge exchange reactions - particularly the technical advances which yielded the recent volume of new date. The present status of charge exchange reactions is reviewed and assessed. Evidence is presented from the 14 C(p,n) reaction for the dominance of the spin-isospin component of the nucleon-nucleon interaction in intermediate energy reactions. In (p,n) reactions the Gamow-Teller giant resonance dominates the spectra, with higher multipoles contributing. By contrast, in (n,p) reactions in the heavier nuclei, the Gamow-Teller transitions are substantially Pauli-blocked and the spin dipole resonance dominates, with contributions from higher multipoles. Discussions of the multipole decomposition process, used to obtain from the data the contributions of the different multipoles, and the contributions of the multipoles, are given

  12. Hipse: an event generator for nuclear collisions at intermediate energies

    International Nuclear Information System (INIS)

    Lacroix, D.; Van Lauwe, A.; Durand, D.

    2003-11-01

    An event generator, HIPSE (Heavy-Ion Phase-Space Exploration), dedicated to the description of nuclear collisions in the intermediate energy range is presented. Based on the sudden approximation and on geometrical hypothesis, it can conveniently simulate heavy-ion interactions at all impact parameters and thus can constitute a valuable tool for the understanding of processes such as neck emission or multifragmentation in peripheral or/and central collisions. After a detailed description of the ingredients of the model, first comparisons with experimental data collected by the INDRA collaboration are shown. Special emphasis is put on the kinematical characteristics of fragments and light particles observed at all impact parameters for Xe+Sn reactions at 25 and 50 MeV/u and Ni + Ni at 82 MeV/u. (authors)

  13. Pitfalls in looking for color transparency at intermediate energies

    International Nuclear Information System (INIS)

    Frankfurt, L.L.; Strikman, M.I.; Zhalov, M.B.

    1994-01-01

    The problems and uncertainties in the search for color transparency at intermediate Q 2 are considered. We show that conventional (optical) model [distorted wave impulse approximation (DWIA)] predicts a substantial change of the transparency, T, with Q 2 in the kinematics of the Ne-18 (e,e ' p) experiment, while the color transparency phenomenon may lead to nearly Q 2 independent T. In the case of A(p,2p) reaction we demonstrate that the conventional optical model describes well the 1 GeV A(p,2p) data but not the transparency observed at higher energies. We find also that DWIA (with or without color transparency) predicts strong dependence of T on the momentum of the struck nucleon which is consistent with the pattern of the Brookhaven National Laboratory A(p,2p) data at p N =6 GeV/c and 10 GeV/c

  14. On selection rules and inelastic electron scattering at intermediate energies

    International Nuclear Information System (INIS)

    Nuroh, K.

    1986-12-01

    Correlation effects are included in the Bethe-Born theory for the generalized oscillator strength of inelastic scattering of electrons on atoms. The formulation is such as to allow for the calculation of relative line strengths of multiplets. It is used to analyze line strengths of the 4d → 4f transition in La 3+ and Ce 4+ within LS-coupling. The analysis indicates that only singlet states of the intermediate 4d 9 4f configuration are allowed. Calculated line strengths are compared with a recent core electron energy loss spectra of metallic La and tetravalent CeO 2 and there is an overall qualitative agreement between theory and experiment. (author). 11 refs, 4 figs, 2 tabs

  15. (γ,2n) reactions in complexe nuclei at intermediate energies

    International Nuclear Information System (INIS)

    Pinheiro Filho, J. de D.

    1976-01-01

    The Monte Carlo Method has been used in the intranuclear cascade model for the calculation of the cross sections of the (γ,2n) reactions in complex nuclei 9 Be, 12 C, 16 O, 59 Co, 103 Rh, 127 I, 197 Au and 209 Bi at intermediate energies (200MeV-1000MeV). The initial photon-interaction via the photomesonic and quasi-deuteron mechanisms have been taken into account. The nuclear model used was a degenerate Fermi gas of nucleons, and the Pauli exclusion principle was considered in all secondary interactions. To improve accuracy in the results of the calculations, 30000 cascades have been followed for each target nucleus at a given incident photon energy. The probabilities of the various (γ,2n) reactions, as well as the correspondent cross section obtained, are summarized in tables and graphs. New data on the cross sections of the 59 Co (γ,2n) and 209 Bi (γ,2n) reactions at photon energies between 300 MeV and 1000MeV are also reported. These measurements were obtained with the Bremsstrahlung beams of the Frascati 1 GeV Electron Synchrotron. A comparison between all existing data in the literature on the (γ,2n) reaction cross sections and the estimates by the Monte Carlo Method, is presented. (Author) [pt

  16. Production of pions and anomalous projectile fragments in heavy ion collisions

    International Nuclear Information System (INIS)

    Noren, B.

    1988-05-01

    Results are presented from investigations of the mean free path (mfp) of multiply charged fragments, produced by 1.8 A GeV argon nuclei. The mfp's have been studied experimentally, and no dependence of the mfp on the distance from the preceeding collision is observed. In a Monte Carlo simulation, the mfp estimators are investigated for different statistics, with or without an enhanced reaction probability. Intermediate energy heavy ion collisions have been studied using the carbon beam produced at the CERN SC-accelerator. Cross-sections for pion + and pion - have been measured over a wide range of angles and targets. Also, coincidence measurements with projectile-like fragments have been performed. The pion - /pion + ratio has been studied for C+Li, C+C, C+Pb, C+ 116 Sn and C+ 124 Sn. Inconsistencies in the target mass dependence of the pion yield disappear if a correction for reabsorption in the target nucleus is included. The projectile breakup is significantly stronger for pion producing collisions than for the average collision, thus indicating a much stronger abundance of central collisions. (With 32 refs.) (author)

  17. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    OpenAIRE

    Kovalenko, S.; Khoriauli, G.; C. Driouchi; J. D. Peso; L. Santi; Soloviev, I.; Arik, E.; Bernabeu, J; M. V. Castillo; Atkinson, T; Tegenfeldt, F.; Weidberg, A.R.; Røhne, O.; F. Anghinolfi; S. Chouridou

    2016-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Gea...

  18. Pion radiation therapy

    International Nuclear Information System (INIS)

    Kligerman, M.M.

    1975-01-01

    Results are summarized from studies on the relative biological effects as compared with x or γ radiation and OER of negative pi mesons produced by the Berkeley 184-inch synchrocyclotron or the NIMROD 7-GeV proton synchrocyclotron at the Rutherford High Energy Laboratory in England using cultured animal cells or Vicia faba cells as the test system. Preliminary results are reported from similar radiobiological studies at the Los Alamos Meson Physics Facility. The relative response of human tissues to peak pion irradiation was compared with 140 kV x rays in a single patient with multiple malignant melanoma by observing the acute response of the skin surrounding metastatic modules following exposure to either pions or x radiation. Color photographs of the irradiated areas made at least twice weekly and densitometry measurements and observations by radiation therapists indicated that maximum erythemia occurred during the fifth, sixth, or seventh week after the start of a schedule of fractionated exposure to 15 fractions over 19 elapsed days. X irradiation was delivered at a dose rate of 500 rads/min to modules to deliver 55, 66, or 75 percent of a skin surface dose of 5,200 rads and pion irradiation, at doses numerically 50 percent of the x ray dose, was delivered at a dose rate of 5 to 7 rads/min. Dose response curves were plotted. Results of histological examinations of skin samples taken 24 weeks following irradiation are reported. Results are discussed relative to the destruction of melanoma cells following pion or x ray treatment

  19. Central collisions in intermediate energy heavy-ion reactions

    International Nuclear Information System (INIS)

    Wong, C.Y.

    1979-01-01

    The critical collisions in intermediate energy heavy-ion reactions are examined from both a microscopic and macroscopic viewpoint. In the microscopic description the proper tool is the extended TDHF approximation involving both the mean field and the particle collisions. To understand the underlying physics, the effect of the mean field and the effect of particle collisions are studied separately. It is found that th sudden increase in the density of the overlapping region can cause the volcano effect, leading to the complete disintegration of one of the nuclei. The self-consistent mean field also gives rise to the bunching instability when the two Fermi spheres of the colliding nucleons separate. The collision between nucleons, on the other hand, leads to irreversible dissipation, thermalization, and the possibility of a hydrodynamical description of the dynamics. Next is studied the dynamics of central collisions using the hydrodynamical description for many combinations of targets and projectiles at different energies. The formation of shock waves, sidesplash, and the complete disintegration of the whole nucleus are examined. Nuclear viscosity is found to affect the angular distribution of the reaction products and also the maximum compression ratio achieved during the collision. 28 references

  20. Pion double charge exchange and nuclear structure

    International Nuclear Information System (INIS)

    Ginocchio, J.N.

    1987-01-01

    Pion double charge exchange to both the double-analog state and the ground state is studied for medium weight nuclei. The relative cross section of these two transitions and the importance of nuclear structure as a function of pion kinetic energy is examined. 16 figs., 5 tabs

  1. Nucleon multiplicities after pion absorption in 160

    International Nuclear Information System (INIS)

    Hamers, R.

    1989-01-01

    The experiment described in this thesis concerns a simultaneous measurement of two- and higher-fold coincidences following positive and negative pion absorption in 16 0. The detected particles are protons, neutrons and deuterons. The detection and analysis of charged particles is discussed. The incident pion energy was 65 MeV, thus well below the delta resonance. The low pion energy was 65 MeV, thus well below the delta resonance. The low pion energy ensures that contributions of initial state interactions, i.e. pion-nucleon scattering preceding absorption, are minimized. The following reaction channels were selected and analyzed: π + ,pp), (π + ,pd). Evidence for quasifree reaction precessed has been investigated by comparing the data with phase-space calculations incorporating the geometry of the experimental setup. (author). 36 refs.; 1 figs.; 3 tabs

  2. Multiplicity fluctuations of pions and protons at SPS energy – An in ...

    Indian Academy of Sciences (India)

    but none of them can explain all the datasets simultaneously. ... in a collision, a new parameter named as 'compound multiplicity' (nc = ng + ns ... sion plates by 32S beam with 200 A GeV incident energy at CERN SPS. ... (b) Grey particles: They are mainly fast target recoil protons with energy up to ..... occurs reverse result.

  3. Radiative pion-proton scattering

    International Nuclear Information System (INIS)

    Ho-Kim, Q.; Lavine, J.P.

    1977-01-01

    The results are presented of a non-relativistic calculation of the π +- proton bremsstrahlung cross section at the pion kinetic energy of 298 MeV for backward photon angles. The pion-nucleon interaction is given by models that are based on the p-wave Chew-Low theory. An interaction current is included in an attempt to make the overall bremsstrahlung amplitude gauge-invariant. The predicted cross sections show little of the expected resonance, and are in fair agreement with the data. The authors have also calculated the cross sections at other kinetic energies, and have studied effects of the off-mass-shell electromagnetic vertex. (Auth.)

  4. Pion-induced fission of 209Bi and 119Sn: measurements, calculations, analyses and comparison

    International Nuclear Information System (INIS)

    Rana, M.A.; Sher, G.; Manzoor, S.; Shehzad, M.I.

    2011-01-01

    Cross-sections for the π - -induced fission of 209 Bi and 119 Sn have been measured using the most sensitive CR-39 solid-state nuclear track detector. In experiments, target–detector stacks were exposed to negative pions of energy 500, 672, 1068, and 1665 MeV at the Brookhaven National Laboratory, USA. An important aspect of the present paper is the comparison of pion-induced fission fragment spectra of above mentioned nuclei with the spontaneous fission fragment spectra of 252 Cf. This comparison is made in terms of fission fragment track lengths in the CR-39 detectors. Measurement results are compared with calculations of Monte Carlo and statistical weight functions methods using the computer code CEM95. Agreement between measurements and calculations is fairly good for 209 Bi target nuclei whereas it is indigent for the case of 119 Sn. The possibilities of the trustworthy calculations, using the computer code CEM95, comparable with measurements of pion-induced fission in intermediate and heavy nuclei are explored by employing various systematics available in the code. Energy dependence of pion-induced fission in 119 Sn and 209 Bi is analyzed employing a newly defined parameter geometric-size-normalized fission cross-section (χ f g ). It is found that the collective nuclear excitations, which may lead to fission, become more probable for both 209 Bi and 119 Sn nuclei with increasing energy of negative pions from 500 to 1665 MeV. (author)

  5. Formation of large target residues in intermediate energy nuclear collisions

    International Nuclear Information System (INIS)

    Loveland, W.; Aleklett, K.; Sihver, L.; Xu, Z.; Seaborg, G.T.

    1987-04-01

    We have used radiochemical techniques to measure the yields, angular distributions and velocity spectra of the large (A/sub frag/ ≥ 2/3 A/sub tgt/) target residues from the fragmentation of 197 Au by intermediate energy 12 C, 20 Ne, 32 S, 40 Ar, 84 Kr, and 139 La projectiles. The fragment moving frame angular distributions are asymmetric for the lighter projectiles (C-Ar). The fragment velocity spectra are Maxwellian for the Kr induced reactions and non-Maxwellian for the reactions induced by the lighter ions. We interpret these results in terms of a change in the dominant fragment production mechanism(s) from one(s) involving a fast non-equilibrium process for the lighter ions to a slow, equilibrium process for Kr. Comparison of the measured yields and angular distributions with calculations made using a Boltzmann transport equation with appropriate modifications for Pauli blocking, etc., show excellent agreement between data and theory. 12 refs., 12 figs

  6. Protons scattering on Li isotopes at intermediate energies

    International Nuclear Information System (INIS)

    Zhusupov, M.A.; Imambekov, O.; Sanfirova, A.V.; Ibraeva, E.T.

    2003-01-01

    The protons scattering differential cross section on the 6,7,8 Li nuclei are calculated within the framework the Glauber-Sitenko multiple scattering theory at intermediate energies (from 100 to 1000 MeV). In the calculations the multi-cluster wave functions (αt for 7 Li, αnp for 6 Li, and αtn for 8 Li) considering within potential cluster model have been used. Differential cross sections for 6 Li, 7 Li, 8 Li and 9 Li nuclei are similar: absolute cross sections are almost the same, diffraction minimum for large A shifting to the field of the least scattering angles that reflecting increase of the material radius. For the 11 Li the differential cross section absolute value is smaller about in two time than for the rest isotopes. At present it is reliably established, that the 11 Li nucleus has an exotic structure - the nine-nucleon core ( 9 Li) around which the two-neutron halo is rotating. The principal characteristics of the Li nuclei are presented in tabular form

  7. Nucleon charge-exchange reactions at intermediate energy

    Energy Technology Data Exchange (ETDEWEB)

    Alford, W.P. [Western Ontario Univ., London, ON (Canada). Dept. of Physics]|[TRIUMF, Vancouver, BC (Canada); Spicer, B.M. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1997-12-31

    An historical review of the development of ideas pertaining to Gamow-Teller giant resonances is given, and a description of the emergence of techniques for the study of charge exchange reactions - particularly the technical advances which yielded the recent volume of new date. The present status of charge exchange reactions is reviewed and assessed. Evidence is presented from the {sup 14}C(p,n) reaction for the dominance of the spin-isospin component of the nucleon-nucleon interaction in intermediate energy reactions. In (p,n) reactions the Gamow-Teller giant resonance dominates the spectra, with higher multipoles contributing. By contrast, in (n,p) reactions in the heavier nuclei, the Gamow-Teller transitions are substantially Pauli-blocked and the spin dipole resonance dominates, with contributions from higher multipoles. Discussions of the multipole decomposition process, used to obtain from the data the contributions of the different multipoles, and the contributions of the multipoles, are given. 226 refs., 19 figs.

  8. Study of the baryon-baryon interaction in nucleon-nucleon and pion-deuteron scattering

    International Nuclear Information System (INIS)

    Fuchs, M.

    1993-01-01

    After the definition of the Hamiltonian in general form by meson production and absorption the transition to operators pursued, which connect only spaces with definite meson numbers. In this approximation first the self-energy of a single baryon was calculated in its full energy and momentum dependence. Then the formal expressions for the T matrices of nucleon-nucleon and pion-deuteron scattering were derived. The essential components of these expressions are the baryon-baryon T matrix ant transition amplitudes from pion-deuteron channels to baryon-baryon states. The central chapter dealt with the calculation of the baryon-baryon interaction for the general form of the vertices, with the solution of the binding problem and the baryon-baryon T matrix. Finally followed the results on the nucleon-nucleon and pion-deuteron scattering. For this first the transition amplitudes from pion-deuteron states to intermediate baryon-baryon states and the Born graphs of the pion-deuteron scattering had to be calculated. After some remarks to the transition from partial-wave decomposed T matrices to scattering observables an extensive representation of the total, partial, and differential cross sections and a series of spin observables (analyzing powers and spin correlations) for the elastic proton-proton, neutron-proton, and pion-deuteron scattering as well for the fusion reaction pp→πd and the breakup reaction πd→pp follows. Thereby the energies reached from the nucleon-nucleon respectively pion-deuteron threshold up to 100 MeV above the delta resonance

  9. Galileo-invariant theory of low energy pion-nucleus scattering. III

    International Nuclear Information System (INIS)

    Mach, R.

    1983-01-01

    Using two versions of the Galileo-invariant optical model, π - - 4 He elastic scattering cross sections were calculated in the energy interval 50 to 260 MeV. Level shifts and widths of several light π-mesoatoms were estimated in the Born approximation. Whereas the (A+1)-body model appears to be more suitable in the resonance region, the two-body model yields surprisingly good results for both the low-energy scattering and the characteristics of π-mesoatoms. (author)

  10. Nuclear structure studies with pions and light and heavy ions. Progress report, June 1, 1981-May 31, 1984

    International Nuclear Information System (INIS)

    Dehnhard, D.

    1984-01-01

    A large number of experiments were done using pion and proton beams at intermediate energies to investigate different excitation modes of the nucleus. Pions were found to be especially suited to excite magnetic transitions of high multipolarity (M4's). The isospin, or neutron/proton, structure of many transitions could be unraveled and detailed comparisons with the predictions of large-space shell-model calculations were successful in many cases. A few glaring exceptions were found to the general good agreement between theory and experiment. For the collectively enhanced electric quadrupole (E2) and octupole (E3) transitions, effective charge enhancements were needed to fit the pion and proton data. The polarization charges were usually found to be in good agreement with the results of electromagnetic measurements. Studies of the excitation of giant resonances by pion inelastic scattering indicated a large isovector component in the transitions to isoscalar giant resonances. This result, although theoretically unexpected, is supported by comparison of electron and alpha-particle scattering and requires further study. A very recent experiment on pion inelastic scattering from 4 He showed little evidence for isospin mixing in this nucleus, in contrast to the conclusions drawn from (γ,n) and (γ,p) work. A high precision elastic π + scattering experiment on 4 He is underway. The work on heavy-ion elastic scattering was completed and terminated. Two experiments are presently being done at lower energies to supplement the work at intermediate energy

  11. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    Czech Academy of Sciences Publication Activity Database

    Abat, E.; Abdallah, J.M.; Addy, T.N.; Lokajíček, Miloš; Němeček, Stanislav

    2010-01-01

    Roč. 6, č. 6 (2010), P06001/1-P06001/28 ISSN 1748-0221 R&D Projects: GA MŠk LA08047 Institutional research plan: CEZ:AV0Z10100502 Keywords : ATLAS * calorimeter methods * calorimeters * detector modelling and simulations * pattern recognition * cluster finding * calibration and fitting methods Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 3.148, year: 2010

  12. Electronic emission produced by light projectiles at intermediate energies

    International Nuclear Information System (INIS)

    Bernardi, G.C.

    1989-01-01

    Two aspects of the electronic emission produced by light projectiles of intermediate energies have been studied experimentally. In the first place, measurements of angular distributions in the range from θ = 0 deg -50 deg induced by collisions of 50-200 keV H + incident on He have been realized. It was found that the double differential cross section of electron emission presents a structure focussed in the forward direction and which extends up to relatively large angles. Secondly, the dependence of the double differential cross section on the projectile charge was studied using H + and He 3 2+ projectiles of 50 and 100 keV/amu incident on He. Strong deviations from a constant scaling factor were found for increasing projectile charge. The double differential cross sections and the single differential cross sections as a function of the emission angle, and the ratios of the emissions induced by He 3 2+ and H + at equal incident projectile velocities are compared with the 'Continuum Distorted Wave-Eikonal Initial State' (CDW-EIS) approximation and the 'Classical Trajectory Monte Carlo' (CTMC) method. Both approximations, in which the potential of the projectile exercises a relevant role, reproduce the general aspects of the experimental results. An electron analyzer and the corresponding projectile beam line has been designed and installed; it is characterized by a series of properties which are particularly appropriate for the study of double differential electronic emission in gaseous as well as solid targets. The design permits to assure the conditions to obtain a well localized gaseous target and avoid instrumental distortions of the measured distributions. (Author) [es

  13. Production of positive pions from polarized protons by linearly polarized photons in the energy region 300--420 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Gorbenko, V.G.; Grushin, V.F.; Derkach, A.Y.; Zhebrovskii, Y.V.; Karnaukhov, I.M.; Kolesnikov, L.Y.; Luchanin, A.A.; Rubashkin, A.L.; Sanin, V.M.; Sorokin, P.V.; Sporov, E.A.; Telegin, Y.N.; Shalatskii, S.V.

    1980-10-01

    A technique for measurement of the polarization observables ..sigma.., P, and T for the reaction ..gamma..p..-->..n..pi../sup +/ in a doubly polarized experiment (polarized proton target + linearly polarized photon beam) is described. Measurements of the angular distributions of these observables in the range of pion emission angles 30--150/sup 0/ are presented for four photon energies from 300 to 420 MeV. Inclusion of the new experimental data in an energy-independent multipole analysis of photoproduction from protons permits a more reliable selection of solutions to be made.

  14. Double charge exchange of pions on nuclei

    International Nuclear Information System (INIS)

    Dzhibuti, R.I.; Kezerashvili, R.Y.

    1985-01-01

    An analysis is made of the results of experimental and theoretical studies during the last ten years of a unique process: double charge exchange of pions on nuclei. On the one hand, the commissioning of meson factories and the use of new and more accurate experimental methods have led to the accumulation of rich and reliable material for not only light but also medium and heavy nuclei. On the other hand, the development and application of new microscopic theoretical approaches have led to a deepening of our ideas about the mechanism of these exotic reactions at low, intermediate, and high energies. The currently existing methods of theoretical investigation and all possible reaction mechanisms are considered. Particular attention is devoted to double charge exchange of pions on the lightest nuclei, for the theoretical description of which it is possible to use the well-developed methods for investigating few-particle systems. The experimental investigations of double-isobar analog and nonanalog transitions in the reaction of double charge exchange are systematized

  15. Dosimetry of pion beams

    International Nuclear Information System (INIS)

    Dicello, J.F.

    1975-01-01

    Negative pion beams are probably the most esoteric and most complicated type of radiation which has been suggested for use in clinical radiotherapy. Because of the limited availability of pion beams in the past, even to nuclear physicists, there exist relatively fewer basic data for this modality. Pion dosimetry is discussed

  16. Pion interferometric tests of transport models

    Energy Technology Data Exchange (ETDEWEB)

    Padula, S.S.; Gyulassy, M.; Gavin, S. (Lawrence Berkeley Lab., CA (USA). Nuclear Science Div.)

    1990-01-08

    In hadronic reactions, the usual space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. We derive a general interferometry formula based on the Wigner density formalism that allows for arbitrary phase space and multiparticle correlations. Correction terms due to intermediate state pion cascading are derived using semiclassical hadronic transport theory. Finite wave packets are used to reveal the sensitivity of pion interference effects on the details of the production dynamics. The covariant generalization of the formula is shown to be equivalent to the formula derived via an alternate current ensemble formalism for minimal wave packets and reduces in the nonrelativistic limit to a formula derived by Pratt. The final expression is ideally suited for pion interferometric tests of Monte Carlo transport models. Examples involving gaussian and inside-outside phase space distributions are considered. (orig.).

  17. Pion interferometric tests of transport models

    International Nuclear Information System (INIS)

    Padula, S.S.; Gyulassy, M.; Gavin, S.

    1990-01-01

    In hadronic reactions, the usual space-time interpretation of pion interferometry often breaks down due to strong correlations between spatial and momentum coordinates. We derive a general interferometry formula based on the Wigner density formalism that allows for arbitrary phase space and multiparticle correlations. Correction terms due to intermediate state pion cascading are derived using semiclassical hadronic transport theory. Finite wave packets are used to reveal the sensitivity of pion interference effects on the details of the production dynamics. The covariant generalization of the formula is shown to be equivalent to the formula derived via an alternate current ensemble formalism for minimal wave packets and reduces in the nonrelativistic limit to a formula derived by Pratt. The final expression is ideally suited for pion interferometric tests of Monte Carlo transport models. Examples involving gaussian and inside-outside phase space distributions are considered. (orig.)

  18. Backward pion photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Sibirtsev, A; Haidenbauer, J; Huang, F; Krewald, S; Meissner, U -G

    2009-04-01

    We present a systematic analysis of backward pion photoproduction for the reactions $ \\gamma$ p $ \\rightarrow$ $ \\pi^{0}_{}$ p and $ \\gamma$ p $ \\rightarrow$ $ \\pi^{+}_{}$ n . Regge phenomenology is applied at invariant collision energies above 3GeV in order to fix the reaction amplitude. A comparision with older data on $ \\pi^{0}_{}$ - and $ \\pi^{+}_{}$ -photoproduction at $ \\vartheta$ = 180° indicates that the high-energy limit as given by the Regge calculation could be reached possibly at energies of around $ \\sqrt{{s}}$ ≃ 3 GeV. In the energy region of $ \\sqrt{{s}}$ $ \\le$2.5 GeV, covered by the new measurements of $ \\gamma$ p $ \\rightarrow$ $ \\pi^{0}_{}$ p differential cross-sections at large angles at ELSA, JLab, and LEPS, we see no clear signal for a convergence towards the Regge results. The baryon trajectories obtained in our analysis are in good agreement with those given by the spectrum of excited baryons.

  19. Single pion production by high energy neutrinos in a hydrogen bubble chamber

    International Nuclear Information System (INIS)

    French, H.T.

    1977-01-01

    The reaction νp → μ - pπ + was observed in the Fermilab 15 foot bubble chamber. The wide band horn focused neutrino beam provided neutrinos with energies from less than 5 GeV to more than 100 GeV. Of 51 νp → μ - pπ + events seen 33 are consistent with the pπ + coming from the Δ ++ (1232) resonance, corresponding to a cross section for νp → μ - Δ ++ 0.65 +- 20 x 10 -38 cm 2 . The data are consistent with the hypothesis that the cross section is independent of neutrino energy above 1 GeV. No evidence is seen for production of higher mass Δ resonances. More events are seen at high Q 2 (four momentum transfer squared to the hadron system) than are expected for presently accepted axial vector form factors. The values of M/sub A/ in the axial vector form factors were found which maximize likelihood that Adler's model fits the cross section and kinematic distribution of the Δ ++ events. For dipole form factors M/sub A/ = 1.6 +- 3 GeV. For monopole form factors M/sub A/ = 0.9 +- 3 GeV. No preference is shown between the monopole and the dipole pages

  20. Experimental study of the pion-xenon nucleus collisions at 3.5 GeV/c. Neutral pion production

    International Nuclear Information System (INIS)

    Strugalski, Z.; Abrosimov, A.T.; Wosinska, K.; Pawlak, T.; Nluta, J.; Sredniawa, B.; Il'ina, A.N.; Okhrimenko, L.S.; Peryt, W.; Miller, K.

    1983-01-01

    Experimental investigations of the neutral pion production are performed in pion-xenon collisions at 3.5 GeV/c. It is obtained that: 1) the average neutral pion multiplicity changes with the multiplicity of the protons emitted; 2) nearly 20% of the pions produced are emitted into the backward hemisphere; 3) the energy spectrum of the neutral pions is smooth; 4) the longitudinal component of the neutral pion momentum changes within the limits from -600 MeV/c to +1800 MeV/c; 5) the average value of the transversal component of the neutral pion momentum changes with the multiplicity of the protons emitted from approximately 270 to approximately 170 MeV/c; 6) the average value of the cosine of the neutral pion emission angle decreases with the multiplicity of the protons emitted

  1. Measurement of the dechanneling length for high-energy negative pions

    International Nuclear Information System (INIS)

    Scandale, W.; Losito, R.; Bagli, E.; Bandiera, L.; Dalpiaz, P.; Fiorini, M.; Guidi, V.; Mazzolari, A.; Vincenzi, D.; Della Mea, G.; Vallazza, E.; Afonin, A.G.; Chesnokov, Yu.A.; Maisheev, V.A.; Yazynin, I.A.; Kovalenko, A.D.; Taratin, A.M.; Denisov, A.S.; Gavrikov, Yu.A.; Ivanov, Yu.M.

    2013-01-01

    We studied the dechanneling length of 150 GeV/cπ − interacting with a short bent silicon crystal. Dechanneling length measures the rate and the strength of incoherent interactions of channeled particles in a crystal. The mechanism of dechanneling of negatively charged particles has been elucidated through simulation and experiment. It was found that the dechanneling length for negative particles is comparable to the nuclear dechanneling length for positive charges. Indeed, dechanneling of negative particles occurs as a result of incoherent interactions with the nuclei because the trajectories of such particles always intersect atomic planes, explaining the lower channeling efficiency for such particles. Obtained results can be useful for the design of crystals for manipulating high-energy negative particle beams through channeling

  2. Dynamic processes in heavy-ion collisions at intermediate energies

    Science.gov (United States)

    Prendergast, E. P.

    1999-03-01

    This thesis describes the study of the reaction dynamics in heavy-ion collisions of small nuclear systems at intermediate energies. For this, experiments were performed of 24Mg+27A1 at 45 and 95 AMeV. The experiments described in this thesis were performed at the GANIL accelerator facility in Caeri (France) using the Huygens detectors in conjunction with the ‘MUR’. The Huygens detectors consist of the CsI(Tl)-Wall (CIW) covering the backward hemisphere and, located at mid-rapidity, the central trigger detector (CTD), a gas chamber with microstrip read-out backed by 48 plastic scintillators. The forward region is covered by 16 of the plastic scintillators of the CTD and by the MUR, a time-of-flight wall consisting of 96 plastic scintillator sheets. In earlier experiments only fragments with atomic number, Z, greater then two could be identifled in the CTD. Therefore, an investigation was done into the properties of different drift gases. The use of freon (CF4) in the drift chamber, combined with an increase of the gas pressure to 150 mbar, makes it possible to identify all particles with Z ≥ 2. Under these conditions particles with Z = 1 can only be identifled to approximately 25 AMeV. The Isospin Quantum Molecular Dynamics (IQMD) model has been used, to interpret the measured data. This model gives a microscopical description of heavy-ion collisions and simulates collisions on an event by event basis. In IQMD all protons and neutrons are represented as individual Gaussian wave packets. After initialisation the path of each nucleon is calculated for 200 fm/c, after which the simulation is stopped. At this time, nucleons which are close in space are clustered into fragments. The events generated by IQMD can then be processed by a GEANT detector simulation. This calculation takes into account the effects of the detector on the incoming particles. By using the GEANT simulation it is possible to give a direct comparison between the results of IQMD and the

  3. Contribution to π+p inelastic scattering at incoming pion energies near 1 GeV

    International Nuclear Information System (INIS)

    Deler, B.

    1969-01-01

    Results on π + p scattering at 810 and 1300 MeV incoming kinetic energy are presented. In the three-body final states (π + p → π + π 0 p or π + π + n) the N * 33 production is strongly dominant. At 1300 MeV one also observes the ρ, N * 1/2 3/2 and N * 1/2 5/2 productions. The difficulty in correctly separating these channels demands trying a more general analysis, taking simultaneously into account several processes (N * π, ρN,...). A generalized isobaric model is discussed. Assuming the interaction of particles by pairs, we can carry out a partial wave analysis of the three body final state reactions. The expansion of the differential cross section in spherical harmonics for data between 600 and 1460 MeV (compilation of data from different laboratories) leads to a simple discussion of the angular effects for different parts of the Dalitz plot. A partial wave analysis has been made below 1 GeV. The reaction p π + π 0 is correctly explained by considering only the N * 33 production. The different partial waves are in agreement with the elastic phase shift analysis, except for the wave SD1 (corresponding to the elastic wave S31) which is found to be small. Therefore, the S31 resonance appears weakly coupled to the N * 33 -π channel. (author) [fr

  4. Multi-pion production

    International Nuclear Information System (INIS)

    Beavis, D.; Fung, S.Y.; Gorn, W.; Keane, D.; Liu, Y.M.; Poe, R.T.; VanDalen, G.; Vient, M.

    1984-01-01

    Preliminary analysis of pion production in 1.2 GeV/nucleon Kr-RbBr collisions is presented. The negative pion multiplicity is consistent with a convolution of Poisson distributions and a freeze-out density between 1/3 and 1/2 normal nuclear density is extracted. Global negative pion kinematic variables are used to search for possible structure in the multi-pion emission. No evidence for structured emission or conservation constraints is found. Pion interferometry analysis gives a source radius of 5.4 +- 1.2 Fermi and a freeze-out density of .3 +- .2 times normal nuclear density. 10 refs., 5 figs

  5. Carbon emission, energy consumption and intermediate goods trade: A regional study of East Asia

    International Nuclear Information System (INIS)

    Zhang, Jingjing

    2015-01-01

    Using country level panel data from East Asia over the period 1998–2011, this paper examines the implications of international production fragmentation-induced intermediate goods trade on the link between energy consumption and carbon pollution. The paper focuses on the interaction effect between energy consumption and trade in intermediate goods on carbon emission. The empirical results presented suggest that international trade in intermediate goods decreases the positive impact on carbon emission of energy consumption. When compared with the trade in final goods, intermediate goods trade contributes to a greater decrease in carbon pollution resulting from energy consumption. These results confirm that the link between energy consumption and carbon pollution in East Asia is significantly affected by international production fragmentation-induced trade in intermediate goods. The results presented in this paper have some important policy implications. - Highlights: • This paper tests the role of intermediates trade in energy-development nexus. • Empirical study is based on data of East Asia. • International trade can reduce the carbon pollution caused by energy use. • Intermediates trade has higher moderating effect than non-intermediate trade.

  6. Multiplicity dependence of charged pion, kaon, and (anti)proton production at large transverse momentum in p-Pb collisions at $\\sqrt{s_{\\rm NN}}$= 5.02 TeV

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Shakeel; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Millan Almaraz, Jesus Roberto; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Benacek, Pavel; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biro, Gabor; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blair, Justin Thomas; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botta, Elena; Bourjau, Christian; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Bashir Butt, Jamila; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Carnesecchi, Francesca; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Ceballos Sanchez, Cesar; Cerello, Piergiorgio; Cerkala, Jakub; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chauvin, Alex; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Cho, Soyeon; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danisch, Meike Charlotte; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Conti, Camila; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; Deplano, Caterina; Dhankher, Preeti; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Drozhzhova, Tatiana; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Endress, Eric; Engel, Heiko; Epple, Eliane; Erazmus, Barbara Ewa; Erdemir, Irem; Erhardt, Filip; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Feuillard, Victor Jose Gaston; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Fleck, Martin Gabriel; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fronze, Gabriele Gaetano; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Gasik, Piotr Jan; Gauger, Erin Frances; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Coral, Diego Mauricio; Gomez Ramirez, Andres; Gonzalez, Victor; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Grachov, Oleg Anatolievich; Graczykowski, Lukasz Kamil; Graham, Katie Leanne; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Gronefeld, Julius Maximilian; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hamon, Julien Charles; Harris, John William; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hillemanns, Hartmut; Hippolyte, Boris; Horak, David; Hosokawa, Ritsuya; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Inaba, Motoi; Incani, Elisa; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacazio, Nicolo; Jacobs, Peter Martin; Jadhav, Manoj Bhanudas; Jadlovska, Slavka; Jadlovsky, Jan; Jahnke, Cristiane; Jakubowska, Monika Joanna; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karayan, Lilit; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Do Won; Kim, Dong Jo; Kim, Daehyeok; Kim, Hyeonjoong; Kim, Jinsook; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; Klewin, Sebastian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Kondratyuk, Evgeny; Konevskikh, Artem; Kopcik, Michal; Kostarakis, Panagiotis; Kour, Mandeep; Kouzinopoulos, Charalampos; Kovalenko, Oleksandr; Kovalenko, Vladimir; Kowalski, Marek; Koyithatta Meethaleveedu, Greeshma; Kralik, Ivan; Kravcakova, Adela; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kubera, Andrew Michael; Kucera, Vit; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kumar, Ajay; Kumar, Jitendra; Lokesh, Kumar; Kumar, Shyam; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; Laudi, Elisa; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Lee, Seongjoo; Lehas, Fatiha; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Li, Shuang; Li, Xiaomei; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loginov, Vitaly; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lowe, Andrew John; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Lutz, Tyler Harrison; Maevskaya, Alla; Mager, Magnus; Mahajan, Sanjay; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Margutti, Jacopo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martin, Nicole Alice; Martin Blanco, Javier; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martinez Pedreira, Miguel; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Mcdonald, Daniel; Meddi, Franco; Melikyan, Yuri; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mieskolainen, Matti Mikael; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Minervini, Lazzaro Manlio; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Moreira De Godoy, Denise Aparecida; Perez Moreno, Luis Alberto; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Munzer, Robert Helmut; Murakami, Hikari; Murray, Sean; Musa, Luciano; Musinsky, Jan; Naik, Bharati; Nair, Rahul; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Ferreira Natal Da Luz, Pedro Hugo; Nattrass, Christine; Rosado Navarro, Sebastian; Nayak, Kishora; Nayak, Ranjit; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Cabanillas Noris, Juan Carlos; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Orava, Risto; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pal, Susanta Kumar; Pan, Jinjin; Pandey, Ashutosh Kumar; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Pei, Hua; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Perez Lezama, Edgar; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Ozelin De Lima Pimentel, Lais; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Rami, Fouad; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sarkar, Debojit; Sarma, Pranjal; Scapparone, Eugenio; Scarlassara, Fernando; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Sefcik, Michal; Seger, Janet Elizabeth; Sekiguchi, Yuko; Sekihata, Daiki; Selyuzhenkov, Ilya; Senosi, Kgotlaesele; Senyukov, Serhiy; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabanov, Arseniy; Shabetai, Alexandre; Shadura, Oksana; Shahoyan, Ruben; Shahzad, Muhammed Ikram; Shangaraev, Artem; Sharma, Ankita; Sharma, Mona; Sharma, Monika; Sharma, Natasha; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Sielewicz, Krzysztof Marek; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Snellman, Tomas Wilhelm; Soegaard, Carsten; Song, Jihye; Song, Myunggeun; Song, Zixuan; Soramel, Francesca; Sorensen, Soren Pontoppidan; Derradi De Souza, Rafael; Sozzi, Federica; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Stachel, Johanna; Stan, Ionel; Stankus, Paul; Stefanek, Grzegorz; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Suljic, Miljenko; Sultanov, Rishat; Sumbera, Michal; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Tabassam, Uzma; Takahashi, Jun; Tambave, Ganesh Jagannath; Tanaka, Naoto; Tangaro, Marco-Antonio; Tarhini, Mohamad; Tariq, Mohammad; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trombetta, Giuseppe; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vechernin, Vladimir; Veen, Annelies Marianne; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Villatoro Tello, Abraham; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Watanabe, Daisuke; Watanabe, Yosuke; Weber, Michael; Weber, Steffen Georg; Weiser, Dennis Franz; Wessels, Johannes Peter; Westerhoff, Uwe; Whitehead, Andile Mothegi; Wiechula, Jens; Wikne, Jon; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yasin, Zafar; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yoon, Jin Hee; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

    2016-09-10

    The production of charged pions, kaons and (anti)protons has been measured at mid-rapidity ($-0.5 10$ GeV/$c$), the particle ratios are consistent with those reported for pp and Pb-Pb collisions at the LHC energies. At intermediate $p_{\\rm T}$ the (anti)proton $R_{\\rm pPb}$ shows a Cronin-like enhancement, while pions and kaons show little or no nuclear modification. At high $p_{\\rm T}$ the charged pion, kaon and (anti)proton $R_{\\rm pPb}$ are consistent with unity within statistical and systematic uncertainties.

  7. Scrutinizing the pion condensed phase

    Energy Technology Data Exchange (ETDEWEB)

    Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)

    2017-02-15

    When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)

  8. SCATPI, a subroutine for calculating πN cross sections and polarizations for incident pion kinetic energies between 90 and 300 MeV

    International Nuclear Information System (INIS)

    Walter, J.B.; Rebka, G.A. Jr.

    1979-03-01

    A subroutine, SCATPI, was written which calculates π + p elastic differential cross sections for incident pion kinetic energies between 90 and 310 MeV for π - p. The calculation is based upon the phase shift analysis of Carter, Bugg, and Carter, and is reliable to about 2% for π + p and 3% for π - p differential cross sections. SCATPI also calculates other scattering parameters for the π+-p systems. The calculations are compared with the measurements used in the phase shift analysis, and with selected recent measurements. The use of SCATPI is described. 14 figures, 4 tables

  9. The pion electromagnetic form factor in the time-like energy range 1.35≤√s≤2.4 GeV

    International Nuclear Information System (INIS)

    1988-10-01

    The e + e - → π + π - cross section has been measured from about 280 events (an order of magnitude more than the previous world statistics) in the energy interval 1.35≤√s≤2.4 GeV with the DM2 detector at DCI. The pion squared form factor shows a deep minimum around 1.6 GeV/c 2 and is best fit under the hypothesis of two ρ like resonances ≅ 0.2 GeV/c 2 wide with 1.43 and 1.76 GeV/c 2 masses

  10. Pion-nucleus cross sections approximation

    International Nuclear Information System (INIS)

    Barashenkov, V.S.; Polanski, A.; Sosnin, A.N.

    1990-01-01

    Analytical approximation of pion-nucleus elastic and inelastic interaction cross-section is suggested, with could be applied in the energy range exceeding several dozens of MeV for nuclei heavier than beryllium. 3 refs.; 4 tabs

  11. Funny hills in pion spectra from heavy-ion collisions

    International Nuclear Information System (INIS)

    Rasmussen, J.O.

    1982-03-01

    A discussion of some of the systematic features of the pion spectra in heavy-ions reactions is given. A discussion of the hills and valleys in heavy ion pion spectra that show up at the lower pion energies is given. The following topics are discussed: (1) three kinds of funny hills; (2) π - / + ratios near center of mass; (3) new Monte Carlo studies of charged pion spectra; and (4) pion orbiting about fireballs and Bose-Einstein behavior as explanation for the mid-rapidity P/sub perpendicular to/ approx. = 0.4 to 0.5 m/sub π/c hill

  12. Elliptic flow of charged pions, protons and strange particles emitted in Pb + Au collisions at top SPS energy

    International Nuclear Information System (INIS)

    Adamová, D.; Agakichiev, G.; Andronic, A.; Antończyk, D.; Appelshäuser, H.; Belaga, V.; Bielčíková, J.; Braun-Munzinger, P.; Busch, O.; Cherlin, A.; Damjanović, S.; Dietel, T.; Dietrich, L.; Drees, A.; Dubitzky, W.; Esumi, S.I.; Filimonov, K.

    2012-01-01

    Differential elliptic flow spectra v 2 (p T ) of π - , K S 0 , p, Λ have been measured at √(s NN )=17.3 GeV around midrapidity by the CERN-CERES/NA45 experiment in mid-central Pb + Au collisions (10% of σ geo ). The p T range extends from about 0.1 GeV/c (0.55 GeV/c for Λ) to more than 2 GeV/c. Protons below 0.4 GeV/c are directly identified by dE/dx. At higher p T , proton elliptic flow is derived as a constituent, besides π + and K + , of the elliptic flow of positive pion candidates. This retrieval requires additional inputs: (i) of the particle composition, and (ii) of v 2 (p T ) of positive pions. For (i), particle ratios obtained by NA49 are adapted to CERES conditions; for (ii), the measured v 2 (p T ) of negative pions is substituted, assuming π + and π - elliptic flow magnitudes to be sufficiently close. The v 2 (p T ) spectra are compared to ideal-hydrodynamics calculations. In synopsis of the series π - -K S 0 -p-Λ, flow magnitudes are seen to fall with decreasing p T progressively even below hydro calculations with early kinetic freeze-out (T f =160 MeV) leaving not much time for hadronic evolution. The proton v 2 (p T ) data show a downward swing towards low p T with excursions into negative v 2 values. The pion-flow isospin asymmetry observed recently by STAR at RHIC, invalidating in principle our working assumption, is found in its impact on proton flow bracketed from above by the direct proton flow data, and not to alter any of our conclusions. Results are discussed in perspective of recent viscous hydrodynamics studies which focus on late hadronic stages.

  13. Elliptic flow of charged pions, protons and strange particles emitted in Pb + Au collisions at top SPS energy

    Science.gov (United States)

    Adamová, D.; Agakichiev, G.; Andronic, A.; Antończyk, D.; Appelshäuser, H.; Belaga, V.; Bielčíková, J.; Braun-Munzinger, P.; Busch, O.; Cherlin, A.; Damjanović, S.; Dietel, T.; Dietrich, L.; Drees, A.; Dubitzky, W.; Esumi, S. I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glässel, P.; Hering, G.; Holeczek, J.; Kalisky, M.; Krobath, G.; Kushpil, V.; Maas, A.; Marín, A.; Milošević, J.; Miśkowiec, D.; Panebrattsev, Y.; Petchenova, O.; Petráček, V.; Radomski, S.; Rak, J.; Ravinovich, I.; Rehak, P.; Sako, H.; Schmitz, W.; Schuchmann, S.; Sedykh, S.; Shimansky, S.; Stachel, J.; Šumbera, M.; Tilsner, H.; Tserruya, I.; Tsiledakis, G.; Wessels, J. P.; Wienold, T.; Wurm, J. P.; Yurevich, S.; Yurevich, V.; Ceres Collaboration

    Differential elliptic flow spectra v2(pT) of π-, KS0, p, Λ have been measured at √{sNN}=17.3 GeV around midrapidity by the CERN-CERES/NA45 experiment in mid-central Pb + Au collisions (10% of σgeo). The pT range extends from about 0.1 GeV/c (0.55 GeV/c for Λ) to more than 2 GeV/c. Protons below 0.4 GeV/c are directly identified by dE/dx. At higher pT, proton elliptic flow is derived as a constituent, besides π+ and K+, of the elliptic flow of positive pion candidates. This retrieval requires additional inputs: (i) of the particle composition, and (ii) of v2(pT) of positive pions. For (i), particle ratios obtained by NA49 are adapted to CERES conditions; for (ii), the measured v2(pT) of negative pions is substituted, assuming π+ and π- elliptic flow magnitudes to be sufficiently close. The v2(pT) spectra are compared to ideal-hydrodynamics calculations. In synopsis of the series π--KS0-p-Λ, flow magnitudes are seen to fall with decreasing pT progressively even below hydro calculations with early kinetic freeze-out (Tf=160 MeV) leaving not much time for hadronic evolution. The proton v2(pT) data show a downward swing towards low pT with excursions into negative v2 values. The pion-flow isospin asymmetry observed recently by STAR at RHIC, invalidating in principle our working assumption, is found in its impact on proton flow bracketed from above by the direct proton flow data, and not to alter any of our conclusions. Results are discussed in perspective of recent viscous hydrodynamics studies which focus on late hadronic stages.

  14. Design and construction of a spectrometer facility and experiment for intermediate energy proton scattering on helium

    International Nuclear Information System (INIS)

    Rolfe, R.M.

    1976-12-01

    The goal of the research was to investigate proton scattering on nuclei at intermediate energies and in particular to investigate proton scattering on helium. A theoretical investigation of the helium nucleus and the nature of the intermediate energy interaction, design and optimization of an energy-loss spectrometer facility for proton-nucleus scattering, and the unique superfluid helium target and experimental design are discussed

  15. An in-beam test study of the response of calorimeters in the ATLAS Experiment of LHC to charged pions of 3 to 350 GeV energy range; Etude en faisceau-test de la reponse des calorimetres de l'Experience ATLAS du LHC a des pions charges, d'energie comprise entre 3 et 350 Gev

    Energy Technology Data Exchange (ETDEWEB)

    Giangiobbe Vincent [Ecole Doctorale des Sciences Fondamentales, Universite Blaise Pascal, U.F.R de Recherches Scientifiques et Techniques, 34, avenue Carnot - BP 185, 63006 Clermont-Ferrand Cedex (France)

    2006-11-15

    ATLAS is one of the four main experiments under way of installing within the Large Hadron Project (LHC). LHC will provide two proton beams of high luminosity (1 x 10{sup 34} cm{sup -2} s{sup -1} at peak), colliding in the center of ATLAS detector at a 14 TeV rated COM energy. The aim of this study is an in-beam test characterization of the response of calorimeters in the central part of ATLAS. The study will be focused on the response to pions as main jet components. In the beginning a short presentation of the ATLAS program of physics is given enlightening the basic theoretical and experimental aspects of the experiment. A description of the ATLAS detector is also presented. The second chapter is devoted to detailed description of the central calorimetry of ATLAS. One starts from the mechanism of signal production in calorimeters, through the electronic processing up to the reconstruction of the released energy. The third chapter deals with the processing electronics of the TileCal hadron calorimeter the installation and certification at CERN of which was in charge of Clermont-Ferrand team. The chapter 4 gives a description of the SPS beam line and of the associated instrumentation tested in-beam in 2004. The chapters 6 and 7 are devoted to the study of the response of calorimeters to high energy pions (within 20 to 350 GeV range). The pion selection is described in the chapter 5. In the eighth chapter the calorimeter response to low energy pions (up to 9 GeV) is examined. In conclusion this study has shown that the data concerning pions obtained in-beam in 2004 are usable for energies within 3 to 350 GeV. The response and the energy resolution of LAr and TileCal were measured with a satisfactory accuracy,. A systematic comparison of these results with simulations (in the configuration of in-beam test) can now be done. Should the agreement be satisfying, the modelling could be used for the study of calibration of calorimeter response for the case of works with the

  16. An in-beam test study of the response of calorimeters in the ATLAS Experiment of LHC to charged pions of 3 to 350 GeV energy range; Etude en faisceau-test de la reponse des calorimetres de l'Experience ATLAS du LHC a des pions charges, d'energie comprise entre 3 et 350 Gev

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, Giangiobbe [Ecole Doctorale des Sciences Fondamentales, Universite Blaise Pascal, U.F.R de Recherches Scientifiques et Techniques, 34, avenue Carnot - BP 185, 63006 Clermont-Ferrand Cedex (France)

    2006-11-15

    ATLAS is one of the four main experiments under way of installing within the Large Hadron Project (LHC). LHC will provide two proton beams of high luminosity (1 x 10{sup 34} cm{sup -2} s{sup -1} at peak), colliding in the center of ATLAS detector at a 14 TeV rated COM energy. The aim of this study is an in-beam test characterization of the response of calorimeters in the central part of ATLAS. The study will be focused on the response to pions as main jet components. In the beginning a short presentation of the ATLAS program of physics is given enlightening the basic theoretical and experimental aspects of the experiment. A description of the ATLAS detector is also presented. The second chapter is devoted to detailed description of the central calorimetry of ATLAS. One starts from the mechanism of signal production in calorimeters, through the electronic processing up to the reconstruction of the released energy. The third chapter deals with the processing electronics of the TileCal hadron calorimeter the installation and certification at CERN of which was in charge of Clermont-Ferrand team. The chapter 4 gives a description of the SPS beam line and of the associated instrumentation tested in-beam in 2004. The chapters 6 and 7 are devoted to the study of the response of calorimeters to high energy pions (within 20 to 350 GeV range). The pion selection is described in the chapter 5. In the eighth chapter the calorimeter response to low energy pions (up to 9 GeV) is examined. In conclusion this study has shown that the data concerning pions obtained in-beam in 2004 are usable for energies within 3 to 350 GeV. The response and the energy resolution of LAr and TileCal were measured with a satisfactory accuracy,. A systematic comparison of these results with simulations (in the configuration of in-beam test) can now be done. Should the agreement be satisfying, the modelling could be used for the study of calibration of calorimeter response for the case of works with the

  17. Role of vector mesons in pion electroproduction

    International Nuclear Information System (INIS)

    Uleshchenko, V.V.

    2007-01-01

    The talk is concerned with mechanisms of pion production in deeply inelastic scattering related to the interaction of virtual photon with the nucleon via an intermediate vector-meson state of the probe. A clear evidence of these mechanisms in the HERMES experimental data is revealed

  18. Pion inelastic scattering and the pion-nucleus effective interaction

    International Nuclear Information System (INIS)

    Carr, J.A.

    1983-01-01

    This work examines pion inelastic scattering with the primary purpose of gaining a better understanding of the properties of the pion-nucleus interaction. The main conclusion of the work is that an effective interaction which incorporates the most obvious theoretical corrections to the impulse approximation does a good job of explaining pion elastic and inelastic scattering from zero to 200 MeV without significant adjustments to the strength parameters of the force. Watson's multiple scattering theory is used to develop a theoretical interaction starting from the free pion-nucleon interaction. Elastic scattering was used to calibrate the isoscalar central interaction. It was found that the impulse approximation did poorly at low energy, while the multiple scattering corrections gave good agreement with all of the data after a few minor adjustments in the force. The distorted wave approximation for the inelastic transition matrix elements are evaluated for both natural and unnatural parity excitations. The isoscalar natural parity transitions are used to test the reaction theory, and it is found that the effective interaction calibrated by elastic scattering produces good agreement with the inelastic data. Calculations are also shown for other inelastic and charge exchange reactions. It appears that the isovector central interaction is reasonable, but the importance of medium corrections cannot be determined. The unnatural parity transitions are also reasonably described by the theoretical estimate of the spin-orbit interaction, but not enough systematic data exists to reach a firm conclusion

  19. On FEL integral equation and electron energy loss in intermediate gain regime

    International Nuclear Information System (INIS)

    Takao, Masaru

    1994-03-01

    The FEL pendulum equation in a intermediate gain small signal regime is investigated. By calculating the energy loss of the electron beam in terms of the solution of the pendulum equation, we confirm the consistency of the FEL equation in intermediate gain regime. (author)

  20. Effects of the pion string at heavy ion collisions

    CERN Document Server

    Mao, Hong

    2005-01-01

    We study the possible signals of the pion string associated with the QCD chiral phase transition in LHC Pb-Pb collision at energy square root s=5.5 TeV. We follow the Kibble-Zurek mechanism to discuss the production and evolution of the pion string. We will show that if the QCD chiral phase transition really takes place in the LHC Pb-Pb collision process and the phase transition is in the second order, the pion string will be inevitably produced and subsequently decay. The main effect of this phenomenon is that there is a generation of a large number of pions in the final state produced by the decay of the pion string, and these pions are mostly distributed in a low momentum region with p143 MeV; also there are lots of neutral pions distributed in a low momentum region with the mean momentum at p21 Me V.

  1. Compound nuclei, binary decay, and multifragmentation in intermediate-energy heavy-ion reactions

    International Nuclear Information System (INIS)

    Moretto, L.G.; Wozniak, G.J.

    1988-07-01

    Hot compound nuclei, frequently produced in intermediate-energy reactions through a variety of processes, are shown to be an important and at times dominant source of complex fragments. 13 refs., 12 figs

  2. Pion-nucleon scattering and isospin violation

    International Nuclear Information System (INIS)

    Meissner, U.G.

    1999-01-01

    The paper discusses low-energy pion-nucleon scattering in the framework of chiral perturbation theory. It is argued that using this theoretical method one is able to match the in some cases impressive experimental accuracy (for the low partial waves). It is also shown how strong and electromagnetic isospin violation can be treated simultaneously. Some first results for neutral pion scattering and the σ-term are given. Copyright (1999) World Scientific Publishing Co. Pte. Ltd

  3. Pions and other hadronic degrees of freedom in nuclei

    International Nuclear Information System (INIS)

    Brockmann, B.; Weise, W.

    1985-01-01

    As ≥E and or ≥q is increased up to several hundreds of MeV, the explicit mesonic degrees of freedom become directly visible. The pion, in particular, is of fundamental importance. With its small mass of m/sub π/ = 140 MeV it is by far the lightest of all mesons. It is the generator of the long range nucleon-nucleon interaction. The pion Compton wavelength psi/sub π/ = Κm/sub π/c = 1.4 fm, defines the length scale of nuclear physics. As mesons become important, nucleons begin to reveal their intrinsic structure. Inseparably connected with pionic degrees of freedom is the role of the Δ(1232), the spin 3/2-isopin 3/2 isobar reached from the nucleon by a strong spin-isopin transition at an excitation energy ΔE = M/sub Δ/ - M ≅ 300 MeV, the Δ-nucleon mass difference. This paper, the position is taken that the nucleus consists of nucleons and their excited states (primarily the ≥ (1232)) which communicate by exchange of mesons (in particular: the pion). Such a description has turned out to be quite successful in correlating various phenomena and data at intermediate energies, remarkably though without the need, so far, for explicit reference to underlying quark degrees of freedom. This progress has gone parallel with the similarly successful meson exchange phenomenology of nucleon-nucleon forces at long and intermediate distances (r ≥ 0.8 fm)

  4. Proton induced fission of {sup 232}Th at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Gikal, K. B., E-mail: kgikal@mail.ru; Kozulin, E. M.; Bogachev, A. A. [JINR, Flerov Laboratory of Nuclear Reactions (Russian Federation); Burtebaev, N. T.; Edomskiy, A. V. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Itkis, I. M.; Itkis, M. G.; Knyazhev, G. N. [JINR, Flerov Laboratory of Nuclear Reactions (Russian Federation); Kovalchuk, K. V.; Kvochkina, T. N. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Piasecki, E. [Heavy Ion Laboratory of Warsaw University (Poland); Rubchenya, V. A. [University of Jyväskylä, Department of Physics (Finland); Sahiev, S. K. [Institute of Nuclear Physics of Ministry of Energy of the Republic of Kazakhstan (Kazakhstan); Trzaska, W. H. [University of Jyväskylä, Department of Physics (Finland); Vardaci, E. [INFN Napoli, Dipartimento di Scienze Fisiche dell’Università di Napoli (Italy)

    2016-12-15

    The mass-energy distributions and cross sections of proton-induced fission of {sup 232}Th have been measured at the proton energies of 7, 10, 13, 20, 40, and 55 MeV. Experiments were carried out at the proton beam of the K-130 cyclotron of the JYFL Accelerator Laboratory of the University of Jyväskylä and U-150m cyclotron of the Institute of Nuclear Physics, Ministry of Energy of the Republic of Kazakhstan. The yields of fission fragments in the mass range A = 60–170 a.m.u. have been measured up to the level of 10−4%. The three humped shape of the mass distribution up has been observed at higher proton energies. The contribution of the symmetric component grows up with increasing proton incident energy; although even at 55 MeV of proton energy the shoulders in the mass energy distribution clearly indicate the asymmetric fission peaks. Evolution of shell structure was observed in the fission fragment mass distributions even at high excitation energy.

  5. Energy Technology Programmes 1993-1998. Intermediate report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-10-01

    The Tekes energy technology research programmes were launched in 1993. The aim is to produce innovative solutions that are efficient, environmentally sound and widely - even globally - applicable. Now Tekes manages a total of 12 energy technology research programmed. Research programmed form a network linking academia and industry. Total funding for the energy technology programmed during the years 1993-1998 is estimated at some FIM 1.5 billion, about half of which will be put up by the Tekes and the rest by the industry. Funding by the Ministry of Trade and Industry covers the first full-scale applications (demonstrations) resulting from the research and development activities. Finnish technology is front-ranking in the efficient use of energy, combustion technology, renewable energy sources and environmental technology. In this report the results and the research activities of the separate programmes is presented and discussed

  6. On the use of distributions of stopping pions as an indicator of the spatial distribution of the high-LET dose in negative pion radiotherapy

    International Nuclear Information System (INIS)

    Brenner, D.J.

    1991-01-01

    A semi-empirical across the treatment volume of a therapeutic negative pion beam. Such beams deliver dose partially at high LET (through alphas and heavier particles produced both directly in pion stars and via intermediate star-produced neutrons), and partially at low LET (through scattering of pions, electrons and muons, as well as protons produced directly from pion stars and via intermediate neutrons). The problem is how to understand the spatial distribution of the high-LET dose, which is responsible for the potentially improved biological response in the treatment volume

  7. Interactions of quarks and gluons with nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, A.H. [Columbia Univ., New York, NY (United States)

    1994-04-01

    Some processes involving the interaction of medium energy quarks and gluons with nuclear matter are described. Possible mechanisms for the A-dependence of the energy loss of leading protons produced in proton-nucleus collisions are given, and an experiment which may help to distinguish these mechanisms is described. A possible color transparency experiment at CEBAF is described. Experiments to measure energy loss of quarks in nuclear matter and the formation time of hadrons are discussed along with the possibilities of measuring {sigma}{sub J}/{psi} and {sigma}{sub {psi}{prime}} at CEBAF.

  8. Pion and kaon correlations in high energy heavy-ion collisions. Annual report, April 1, 1995 - March 31, 1996

    International Nuclear Information System (INIS)

    Wolf, K.L.

    1996-01-01

    Data analysis is in progress for recent experiments performed by the NA44 collaboration with the first running of 160 A GeV 208 Pb-induced reactions at the CERN SPS. Identified singles spectra were taken for pions, kaons, protons, deuterons, antiprotons and antideuterons. Two-pion interferometry measurements were made for semi-central-triggered 208 Pb + Pb collisions. An upgraded multiple-particle spectrometer allows high statistics data sets of identified particles to be collected near mid-rapidity. A second series of experiments will be performed in the fall of 1995 with more emphasis on identical kaon interferometry and on the measurement of rare particle spectra and correlations. Modest instrumentation upgrades by TAMU are designed to increase the trigger function for better impact parameter selection and improved collection efficiency of valid events. An effort to achieve the highest degree of projectile-target stopping is outlined and it is argued that an excitation function on the SPS is needed to better understand reaction mechanisms. Analysis of experimental results is in the final stages at LBL in the EOS collaboration for two-ion interferometry in the 1.2 A GeV Au+Au reaction, taken with full event characterization

  9. dd →3 Hen Reaction at Intermediate Energies

    International Nuclear Information System (INIS)

    Ladygina, N. B.

    2012-01-01

    The dd → 3 Hen reaction is considered at the energies between 200 and 520 MeV. The Alt-Grassberger-Sandhas equations are iterated up to the lowest order terms over the nucleon-nucleon t-matrix. The parameterized 3He wave function including five components is used. The angular dependence of the differential cross section and energy dependence of tensor analyzing power T 20 at the zero scattering angle are presented in comparison with the experimental data. (author)

  10. Soft electromagnetic bremsstrahlung in inelastic hadronic collisions at high and intermediate energies

    International Nuclear Information System (INIS)

    Rueckl, R.

    1978-01-01

    Electromagnetic bremsstrahlung in hadronic collisions was studied extensively at low and intermediate energies. It was found that the infrared divergent term of the cross section describes the data well up to surprisingly large photon energies. Using essentially the same soft photon approximation, production of low mass-low energy electron pairs via internal conversion of soft virtual bremsstrahlung accompanying the production of charged hadrons in hadron-hadron collisions at very high and intermediate energies. The resulting electron yields explain, at least in part, the direct electrons with small transverse momenta seen at the ISR, and are in no contradiction to the rates observed at LAMPF

  11. Study of the Two Pion Photoproduction on Deuterium

    Science.gov (United States)

    Gauss, Lewis P. Graham, Jr.

    Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong inter-action physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the γN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Δ resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large Acceptance

  12. Study of the Two-pion Photoproduction on the Deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Lewis P. [Univ. of South Carolina, Columbia, SC (United States)

    2012-12-01

    Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the yN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Delta resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large

  13. Organizational procedure for the study of pion production and absorption processes on nuclei

    International Nuclear Information System (INIS)

    Banerjee, M.K.; Walker, G.E.

    1983-01-01

    For nuclear processes involving pions, such as pion production/absorption or exchange currents, it is shown that a natural organization involves adoption of the πNN vertex function g/sub π/(q 2 )#betta# 5 tau/sub α/, where q is the pion four-momentum and g/sub π/(m/sub π/ 2 )approx. =13.4 is the renormalized pion-nucleon coupling constant. The result is independent of the form and details of any fundamental interaction Lagrangian. The difference between g/sub π/(q 2 )#betta# 5 tau/sub α/ and the fully-dressed πNN vertex function contributes to amplitudes involving more bosons, e.g., scattering amplitudes (πN→πN), production amplitudes (πN→ππN), etc. Such contributions are mediated through either seagull-like terms or P11 intermediate states. It is pointed out that it is neither necessary nor practical to calculate these partial contributions to scattering and production amplitudes. One can always exploit other approaches, theoretical and phenomenological, to make reasonably good models for the full amplitudes. The usual procedure of including the effects of negative energy parts of the nucleon propagator in interaction potentials, exchange currents, etc., is easily included in the present organization. The result is that from scattering amplitudes, etc; the positive energy nucleon poles are deleted but Z graphs are included

  14. Pion nucleus scattering lengths

    International Nuclear Information System (INIS)

    Huang, W.T.; Levinson, C.A.; Banerjee, M.K.

    1971-09-01

    Soft pion theory and the Fubini-Furlan mass dispersion relations have been used to analyze the pion nucleon scattering lengths and obtain a value for the sigma commutator term. With this value and using the same principles, scattering lengths have been predicted for nuclei with mass number ranging from 6 to 23. Agreement with experiment is very good. For those who believe in the Gell-Mann-Levy sigma model, the evaluation of the commutator yields the value 0.26(m/sub σ//m/sub π/) 2 for the sigma nucleon coupling constant. The large dispersive corrections for the isosymmetric case implies that the basic idea behind many of the soft pion calculations, namely, slow variation of matrix elements from the soft pion limit to the physical pion mass, is not correct. 11 refs., 1 fig., 3 tabs

  15. Pions scatter by nuclei

    International Nuclear Information System (INIS)

    Huefner, J.

    1975-01-01

    Are pions a good tool to study nuclei. If the emphasis of this question rests on ''tool'', the answer must be ''not yet.'' The reason: one does not even understand how a pion interacts with a nucleus. This is part of the many-body problem for strongly interacting particles and its study is a basic problem in physics. One must investigate questions like: Can one understand pion-nucleus interactions from pion-nucleon physics. How does a Δ-resonance look in nuclei. Once one has solved those basic problems, there will be spinoffs in medical, technical and nuclear areas. Then pions can be used as a tool to study nuclear properties

  16. Spin asymmetries for elastic scattering in krypton at intermediate energies

    International Nuclear Information System (INIS)

    Went, M R; McEachran, R P; Lohmann, Birgit; MacGillivray, W R

    2002-01-01

    Measurements of the spin asymmetry for elastic scattering of spin-polarized electrons from krypton are presented, for incident energies in the range 20-200 eV. The measured spin asymmetries are generally small, and do not exceed 0.25 in magnitude at any energy or angle. The experimental results are compared with calculated values of the Sherman function, obtained by solution of the Dirac-Fock equations. The calculations have been performed with the inclusion of polarization and dynamic distortion potentials, and with the addition of an absorption potential to model inelastic processes. For incident energies of 50, 60 and 65 eV, the calculated values of the Sherman function are shown to be extremely sensitive to the details of the model, with the addition of the absorption potential producing dramatically different results

  17. np elastic scattering analyzing power characteristics at intermediate energies

    International Nuclear Information System (INIS)

    Abegg, R.; Davis, C.A.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Healey, D.C.; Miller, C.A.; Rodning, N.L.; Wait, G.D.; Ahmad, M.; Cairns, E.B.; Coombes, G.H.; Lapointe, C.; McDonald, W.J.; Moss, G.A.; Roy, G.; Soukup, J.; Tkachuk, R.R.; Ye, Y.; Watson, J.W.

    1989-06-01

    Recent measurements of charge symmetry breaking in the np system at 477 MeV, and of A oonn for np elastic scattering at 220, 325 and 425 MeV also yield accurate analyzing power data. These data allow the energy dependence of the analyzing power zero-crossing angle and the slope of the analyzing power at the zero-crossing to be determined. The incident neutron energies span a region where the zero-crossing angle is strongly energy dependent (Ε n n > 350 MeV). The results are compared to current phase shift analysis predictions, recently published LAMPF data, and the predictions of the Bonn and Paris potentials. (Author) 13 refs., 2 tabs., 2 figs

  18. Multimode approximation for {sup 238}U photofission at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Demekhina, N. A., E-mail: demekhina@lnr.jinr.ru [Yerevan Physics Institute (Armenia); Karapetyan, G. S. [Yerevan State University (Armenia)

    2008-01-15

    The yields of products originating from {sup 238}U photofission are measured at the bremsstrahlung endpoint energies of 50 and 3500 MeV. Charge and mass distributions of fission fragments are obtained. Symmetric and asymmetric channels in {sup 238}U photofission are singled out on the basis of the model of multimode fission. This decomposition makes it possible to estimate the contributions of various fission components and to calculate the fissilities of {sup 238}U in the photon-energy regions under study.

  19. Covariant density functional theory: The role of the pion

    International Nuclear Information System (INIS)

    Lalazissis, G. A.; Karatzikos, S.; Serra, M.; Otsuka, T.; Ring, P.

    2009-01-01

    We investigate the role of the pion in covariant density functional theory. Starting from conventional relativistic mean field (RMF) theory with a nonlinear coupling of the σ meson and without exchange terms we add pions with a pseudovector coupling to the nucleons in relativistic Hartree-Fock approximation. In order to take into account the change of the pion field in the nuclear medium the effective coupling constant of the pion is treated as a free parameter. It is found that the inclusion of the pion to this sort of density functionals does not destroy the overall description of the bulk properties by RMF. On the other hand, the noncentral contribution of the pion (tensor coupling) does have effects on single particle energies and on binding energies of certain nuclei.

  20. Study of projectile break-up process at intermediate energies

    International Nuclear Information System (INIS)

    Kumar, Harish; Parashari, Siddharth; Tali, Suhail A.

    2016-01-01

    The projectile break-up reactions are explained in terms of incomplete fusion or massive transfer reactions leading to the formation of composite system with less mass, charge and excitation energy, as compared to the complete fusion (CF) process. Since, the existing theoretical models are not applicable to reproduce the experimentally measured ICF, data satisfactory below 10 MeV/nucleon energies; thereby the study of the role of the entrance channel parameters in the fusion reactions is still a relevant problem in establishing the explicit inference regarding the influence of ICF on CF at 4-7 MeV/nucleon energies. Recently reported some studies have also shown that alpha Q-value is also an important parameter which affects the onset of ICF and conflict with the suggestion of Morgenstern et al. Keeping in view the recent aspects, to provide more strength to the aspect of projectile-target mass-asymmetry effect, role of non α-cluster projectile over α-cluster projectile, the present work has been carried out which will be useful to understand a clearer picture about the conflict between mass-asymmetry and projectile structure effect on break-up fusion process. As such, excitation function measurement of residues produced in 13 C + 175 Lu system has been carried out in a series of experiments of comparative study using α-cluster as well as non α-cluster projectiles with deformed heavier target nuclei at lower projectile energies ≈ 4-7 MeV/nucleon

  1. Double differential cross sections for methane molecules at intermediate energies

    International Nuclear Information System (INIS)

    Yavuz, Murat; Ozer, Zehra Nur; Ulu, Melike; Dogan, Mevlut; Okumus, Nimet; Sahlaoui, Mohammed; Benmansour, Houda; Bouamoud, Mammar

    2014-01-01

    Double differential cross sections (DDCS) can be obtained by the measurements of energy and angular distributions of one of the two outgoing electrons by a detector. In this pespective, we used methane molecule as a target that is reasonable to expect to understand ionization mechanisms of polyatomic molecular systems.

  2. Pion production cross sections and associated parameters

    International Nuclear Information System (INIS)

    Bradbury, J.N.

    1985-01-01

    Negative pions have been used for radiotherapy at the meson factories LAMPF (USA), SIN (Switzerland), and TRIUMF (Canada) and have been planned for use at new meson facilities under construction (USSR) and at proposed dedicated medical facilities. Providing therapeutically useful dose rates of pions requires a knowledge of the pion production cross sections as a function of primary proton energy (500 to 1000 MeV), pion energy (less than or equal to100 MeV), production angle, and target material. The current status of the data base in this area is presented including theoretical guidelines for extrapolation purposes. The target material and geometry, as well as the proton and pion beam parameters, will affect the electron (and muon) contamination in the beam which may have an important effect on both the LET characteristics of the dose and the dose distribution. In addition to cross-section data, channel characteristics such as length of pion trajectory, solid-angle acceptance, and momentum analysis will affect dose rate, distribution, and quality. Such considerations are briefly addressed in terms of existing facilities and proposed systems. 16 refs., 6 figs

  3. Mechanisms of photon scattering on nucleons at intermediate energies

    International Nuclear Information System (INIS)

    L'vov, A.I.

    1992-01-01

    The principal question for studies of photon scattering by nucleons and nuclei is the following: Can photon scattering say something new about the structure of these objects in comparisons with photo- and electroproduction investigations? There is a general reason to believe that it is indeed the case. The Hamiltonian of the electromagnetic interaction has, in general, a piece quadratic in the electromagnetic field (the so-called two-photon seagull) which is seen only in two-photon processes, such as Compton scattering. Although the longitudnal part of this seagull is constrained by the gauge invariance, its transverse part is decoupled from the electromagnetic current and cannot be found in photoabsorption processes. The seagull S μν depends on explicit degrees of freedom included into the Hamiltonian. E.g. the non-relativisitic Schroedinger equation has an effective seagull due to the kinetic energy (p - eA) 2 /2M. Its parent relativistic Dirac equation has no seagull at all but has the same low-energy consequences due to additional degrees of freedom (antiparticles). In low-energy nuclear physics, with explicit meson exchanges and meson clouds (i.e. internal polarizability of the nucleons). By explicitly including the mesons into the Hamiltonian one can remove part of the seagulls. Then the rest of them will be a signal for degrees of freedom invisible in photoabsorption at energies of the considered scale. Some seagulls are related with t-channel exchanges in Compton scattering. The π o -exchange is seen in γp-scattering but has no counterpart in photoproduction off the proton. Thus, a complementary study of one- and two-photon reactions provides a way to look in a region of higher energies where direct studies via photoproduction processes may be hard

  4. Multi-functional measurement systems for studying photon-hadron interactions in the intermediate energy range

    International Nuclear Information System (INIS)

    Baranov, P.S.; Vol'nov, M.I.; Eliseev, A.N.

    1983-01-01

    The PION multifunctional time-of-flight measurement system operating on-line with the D-116 computer is described. The system is designed to study proton-hadron interaction processes using the PACHRA synchrotron beam. The following devices are involved into the basic permanent system equipment: two gamma telescope counters, neutron spectrometer, scintillation mass spectrometer, and also cryogenic liquid hydrogen and liquid deuterium targets, ionization chambers, and quantometer. The time-of-flight neutron spectrometer consists of 4 coordinate-sensitive scintillation counters, before which the logic detector operating in the anticoincidence regime is placed. Information acquisition and measurement system control are accomplished by the computer using the CAMAK modules. The above system allows one to observe at the same time different physical processes and to carry out simultaneous measurements in a wide energy range

  5. 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

  6. Salient features of heavy ion reactions in the intermediate energy region

    International Nuclear Information System (INIS)

    Jakobsson, B.

    1987-01-01

    In this lecture the attention is focused on the most central and therefore generally also the most violent collisions. It is necessary to remember that the non-participating volumes could be very different for symmetric and asymmetric reactions. The onset of the multifragmentation channel or rather the cease of the fusion process is the first topic to be discussed. This question is directly related to the limitation in energy and momentum transfer and thus to the question about nuclear transparency. Exclusive data on multifragmentation on an event-by-event basis, which may help the model constructors, is presented as the second topic. In lecture the onset of fragmentation, fragment sizes in multifragmentation processes, the origin of light particle correlations and emission of pions and kaons close to the threshold are discussed

  7. Mass distributions in nucleon-induced fission at intermediate energies

    CERN Document Server

    Duijvestijn, M C; Hambsch, F J

    2001-01-01

    Temperature-dependent fission barriers and fission-fragment mass distributions are calculated in the framework of the multimodal random neck-rupture model (MM-RNRM). It is shown how the distinction between the different fission modes disappears at higher excitation energies, due to the melting of shell effects. The fission-fragment mass yield calculations are coupled to the nuclear reaction code ALICE-91, which takes into account the competition between the other reaction channels and fission. With the combination of the temperature-dependent MM-RNRM and ALICE-91 nucleon-induced fission is investigated at energies between 10 and 200 MeV for nuclei varying from Au to Am. (72 refs).

  8. Proton-4He elastic scattering at intermediate energies

    International Nuclear Information System (INIS)

    Auger, J.P.; Gillespie, J.; Lombard, R.J.

    1975-12-01

    Differential elastic cross sections and polarizations are calculated in a multiple scattering formalism for proton- 4 He scattering for energies in the range 0.6-24GeV and for momentum transfers up to 4.0fmsup(-1). The calculations include Coulomb and spin effects. Corrections due to target-nucleon overlap and charge exchange are estimated. The results are compared with experimental data [fr

  9. Calculation of the intermediate energy activation cross section

    Energy Technology Data Exchange (ETDEWEB)

    Furihata, Shiori; Yoshizawa, Nobuaki [Mitsubishi Research Inst., Inc., Tokyo (Japan)

    1997-03-01

    We discussed the activation cross section in order to predict accurately the activation of soil around an accelerator with high energy and strong intensity beam. For the assessment of the accuracy of activation cross sections estimated by a numerical model, we compared the calculated cross section with various experimental data, for Si(p,x){sup 22}Na, Al(p,x){sup 22}Na, Fe(p,x){sup 22}Na, Si(p,x){sup 7}Be, O(p,x){sup 3}H, Al(p,x){sup 3}H and Si(p,x){sup 3}H reactions. We used three computational codes, i.e., quantum molecular dynamics (QMD) plus statistical decay model (SDM), HETC-3STEP and the semiempirical method developed by Silberberg et.al. It is observed that the codes are accurate above 1GeV, except for {sup 7}Be production. We also discussed the difference between the activation cross sections of proton- and neutron-induced reaction. For the incident energy at 40MeV, it is found that {sup 3}H production cross sections of neutron-induced reaction are ten times as large as those of proton-induced reaction. It is also observed that the choice of the activation cross sections seriously affects to the estimate of saturated radioactivity, if the maximum energy of neutron flux is below 100MeV. (author)

  10. [Measurements of observables of pion-nucleon reactions]. Progress report

    International Nuclear Information System (INIS)

    Sadler, M.E.

    1985-01-01

    This document reports the progress of the research of pion reactions. These include (1) a study to measure observables in the pion-nucleon system in the momentum interval 400 to 700 MeV/c, (2) differential cross section measurements at low energy for pion-nucleon charge exchange, and (3) elastic and inelastic scattering of π +- on 3 H and 3 He. Individual experiments will be indexed separately

  11. Improvement of the intranuclear cascade code of Bruyeres-le-Chatel (BRIC) at low intermediate energy

    International Nuclear Information System (INIS)

    Duarte, H.

    2003-01-01

    The IntraNuclear cascade code of Bruyeres-le-Chatel called BRIC has been extended to low intermediate energy by taking in account some medium effects that are included in other nuclear dynamics models such as BUU or QMD. The results of BRIC 1.4 with the medium effects are in better agreement with experimental data than those of the first version on a wide range of incident energy, especially at low intermediate energy. We may conclude that no preequilibrium model is necessary between our INC and the deexcitation step. (orig.)

  12. ABC's of pion charge exchange

    International Nuclear Information System (INIS)

    Gibbs, W.R.; Kaufmann, W.B.; Siegel, P.B.

    1985-01-01

    Calculations of pion single charge exchange using the PWIA and DWIA are presented. Emphasis is given to the effects of absorbtion and blocking. A microscopic calculation of the 0 0 excitation and low energy angular distribution is in excellent agreement with the data. A fixed nucleon multiple scattering calculation of the pion double charge exchange reaction is presented. Various valence neutron wave functions are used, and the contributions of different spatial orientations of the last two neutrons to the reaction are examined. The DCX cross section is found to be very sensitive to the inclusion of correlations in the two-neutron wave function. Satisfactory agreement with DCX data on 14 C can be obtained using a nucleonic picture of the nucleus

  13. Heavy residue properties in intermediate energy nuclear collisions with gold

    International Nuclear Information System (INIS)

    Aleklett, K.; Sihver, L.; Liljenzin, J.O.; Seaborg, G.T.

    1990-10-01

    We have measured the target fragment production cross sections and angular distributions for the interaction of 32, 44 and 93 MeV/nucleon argon, 35 and 43 MeV/nucleon krypton with gold. The fragment isobaric yield distributions, moving frame angular distributions and velocities have been deduced from these data. This fission cross section decreases with increasing projectile energy and the heavy residue cross section increases. The ratio v parallel /v cn increases approximately linearly with mass removed from the target. 21 refs., 8 figs

  14. Systematics of fission cross sections at the intermediate energy region

    Energy Technology Data Exchange (ETDEWEB)

    Fukahori, Tokio; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-03-01

    The systematics was obtained with fitting experimental data for proton induced fission cross sections of Ag, {sup 181}Ta, {sup 197}Au, {sup 206,207,208}Pb, {sup 209}Bi, {sup 232}Th, {sup 233,235,238}U, {sup 237}Np and {sup 239}Pu above 20 MeV. The low energy cross section of actinoid nuclei is omitted from systematics study, since the cross section has a complicated shape and strongly depends on characteristic of nucleus. The fission cross sections calculated by the systematics are in good agreement with experimental data. (author)

  15. Angular evolution of peripheral heavy ion reactions at intermediate energies

    International Nuclear Information System (INIS)

    Blumenfeld, Y.; Chomaz, P.; Frascaria, N.; Garron, J.P.; Jacmart, J.C; Roynette, J.C

    1985-01-01

    Energy spectra and angular distributions of projectile-like fragments have been measured in the vicinity of the grazing angle for the 40 Ar+ 40 Ca and 40 Ar+ 208 Pb reactions at 44MeV/nucleon. Measurements of the 40 Ar+ 40 Ca system at 27MeV/nucleon and 20 Ne+ 208 Pb reaction at 44MeV/nucleon at one angle have also been performed. For fragments with charge and mass close to the projectile numerous deviations from the standard fragmentation model have been observed including rapidly changing shapes of the angular distributions with the fragment mass. Moreover the isotopic distributions and mean fragment velocities are strongly dependent on detection angle. A surface transfer reaction component dominant at the grazing angle can be separated from a second component which cannot be entirely accounted for by a simple fragmentation mechanism

  16. Plunger lifetime measurements after Coulomb excitation at intermediate beam energies

    Energy Technology Data Exchange (ETDEWEB)

    Hackstein, Matthias; Dewald, Alfred; Fransen, Christoph; Ilie, Gabriela; Jolie, Jan; Melon, Barbara; Pissulla, Thomas; Rother, Wolfram; Zell, Karl-Oskar [University of Cologne (Germany); Petkov, Pavel [University of Cologne (Germany); INRNE (Bulgaria); Chester, Aaron; Adrich, Przemyslaw; Bazin, Daniel; Bowen, Matt; Gade, Alexandra; Glasmacher, Thomas; Miller, Dave; Moeller, Victoria; Starosta, Krzysztof; Stolz, Andreas; Vaman, Constantin; Voss, Philip; Weissharr, Dirk [Michigan State Univerity (United States); Moeller, Oliver [TU Darmstadt (Germany)

    2008-07-01

    Two recoil-distance-doppler-shift (RDDS) experiments were performed at the NSCL/MSU using Coulomb excitations of the projectile nuclei {sup 110}Pd, {sup 114}Pd at beam energies of 54 MeV/u in order to investigate the evolution of deformation of neutron rich paladium isotopes. The experimental set-up consisted of a dedicated plunger device, developed at the University of Cologne, the SEGA Ge-array and the S800 spectrometer. Lifetimes of the 2{sub 1}{sup +}-states in {sup 110}Pd and {sup 114}Pd were derived from the analysis of the {gamma}-line-shapes as well as from the measured decay-curves. Special features of the data analysis, e.g. features originating from the very high recoil velocities, are discussed.

  17. Intermediate energy electron scattering from sodium and potassium

    International Nuclear Information System (INIS)

    Buckman, S.J.

    1979-06-01

    This thesis describes an experimental investigation of the interaction of fast electrons with alkali metal atoms. Several of the theoretical models which have been applied to atomic collision processes including the first Born approximation, the Glauber approximation, the optical model and the distorted wave polarized orbital approximation are discussed. The theory of electron-photon coincidence experiments is outlined and the effects of fine and hyperfine structure on the polarization state of photons emitted from an excited atom are calculated for Sodium. The results of elastic scattering measurements on Sodium and Potassium are presented and used to test several theoretical models in their description of the differential cross section at incident energies between 50 and 200eV. Absolute differential and integrated total cross sections for the Potassium resonance lines and Sodium D-lines are presented. Results of the first electron-polarized photon coincidence experiment on the Sodium D-lines are presented and compared with available theoretical calculations

  18. Deuteron breakup mechanism in the intermediate-energy region

    International Nuclear Information System (INIS)

    Divadeenam, M.; Ward, T.E.

    1991-01-01

    In an earlier investigation, we have explored the possibility of explaining the deuteron breakup mechanism in terms of the Udagawa and Tannura (UT) formalism of the breakup-fusion process. The experimental doubly differential data were very well reproduced for the test case studies. However, the application of UT formalism of the spirit of DWBA involves the use of optical-model parameters for different nuclei and at different energies. The optical model parameters are not always unique. In the present study we investigate the deuteron breakup mechanism in terms of the semiclassical models of Serber (for the nuclear interaction part) and Dancoff (for the electromagnetic dissociation). In the case of Serber model the modification due to the finite range of the deuteron and the Glauber correction for the diffractive disassociation are considered. The modified deuteron breakup cross section either for the (d,p) or the (d,n) process is proportional to the product of the target radius and the deuteron radius (R target · R deuteron ). The predicted proton/neutron spectrum is centered around 1/2 E d and forward peaked. The Coulomb dissociation of deuteron is attributed to the deuteron dipole excitation in the presence of the nuclear Coulomb field. The neutron/proton spectrum, resulting from the Coulomb breakup of the deuteron, is highly forward peaked and also centered around 1/2 E d . The systematics of the deuteron breakup neutron/proton spectra are investigated for medium to heavy target nuclei at 50--200 MeV deuteron energies. 10 refs., 4 figs

  19. Pion observables and QCD

    International Nuclear Information System (INIS)

    Roberts, C.D.

    1995-01-01

    Herein the application of the DSE approach to the calculation of pion observables is described using: the π-π scattering lengths (a 0 0 , a 2 0 , a 1 1 , a 0 2 , a 2 2 ) and associated partial wave amplitudes; the π 0 → γγ decay width; and the charged pion form factor, F π (q 2 ), as illustrative examples. Since this approach provides a straightforward, microscopic description of dynamical chiral symmetry breaking (DχSB) and confinement, the calculation of pion observables is a simple and elegant illustrative example of its power and efficacy. (orig.)

  20. UCLA Intermediate Energy Nuclear and Particle Physics Research: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nefkens, B M.K. [Principal Investigator, ed.; Goetz, J; Lapik, A; Korolija, M; Prakhov, S; Starostin, A [ed.

    2011-05-18

    This project covers the following research: (a) Investigations into the structure of the proton and neutron. This is done by investigating the different resonance states of nucleons with beams of tagged, polarized photons, linearly as well as circularly, incident on polarized hydrogen/deuterium targets and measuring the production of {pi}{sup 0}, 2{pi}{sup }0, 3{pi}{sup 0}, {eta} , {eta}', {omega}, etc. The principal detector is the Crystal Ball multiphoton spectrometer which has an acceptance of nearly 4 . It has been moved to the MAMI accelerator facility of the University of Mainz, Germany. We investigate the conversion of electromagnetic energy into mesonic matter and conversely. (b) We investigate the consequences of applying the "standard" symmetries of isospin, G-parity, charge conjugation, C, P, T, and chirality using rare and forbidden decays of light mesons such as the {eta} ,{eta}' and {omega}. We also investigate the consequences of these symmetries being slightly broken symmetries. We do this by studying selected meson decays using the Crystal Ball detector. (c) We determine the mass, or more precisely the mass difference of the three light quarks (which are inputs to Quantum Chromodynamics) by measuring the decay rate of specially selected {eta} and {eta}' decay modes, again we use the Crystal Ball. (d)We have started a new program to search for the 33 missing cascade baryons using the CLAS detector at the Thomas Jefferson Laboratory. Cascade resonances are very special: they have double strangeness and are quite narrow. This implies that they can be discovered by the missing mass technique in photoproduction reactions such as in {gamma}p{yields}{Xi}{sup}K{sup +}K{sup +}. The cascade program is of particular importance for the upgrade to 12 GeV of the CLAS detector and for design of the Hall D at JLab. (e) Finally, we are getting more involved in a new program to measure the hadronic matter form factor of complex nuclei, in particular

  1. Measurement of the charged-pion polarisability at COMPASS

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    For more than a decade, COMPASS has been tackling the measurement of the electromagnetic polarizability of the charged pion, which describes the stiffness of the pion against deformation in electromagnetic fields. Previous experiments date back to the 1980's in Serpukhov (Russia), where the Primakoff method for realizing interactions of charged pions with quasi-real photons was first employed. Later also other techniques in photon-nucleon and photon-photon collisions were carried out at different machines. The COMPASS measurement demonstrates that the charged-pion polarizability is significantly smaller than the previous results, roughly by a factor two, with the smallest uncertainties realized so far. The pion polarisability is of fundamental interest in the low-energy sector of quantum chromodynamics. It is directly linked to the quark-gluon substructure and dynamics of the pion, the lightest bound system of strong interaction.

  2. Subthreshold pion production of 20-100 MeV energy with various projectiles (p, 3He, 12C, 16O)

    International Nuclear Information System (INIS)

    Sanouillet, G.; Bolore, M.; Charlot, X.

    1986-05-01

    The described experiments refer to pion production below and near the threshold with different projectiles (p, 3 He, 12 C, 16 O). The pion detection device was a range telescope. Experimental methods are presented and discussed. Data are compared to predictions of some models [fr

  3. Low-energy consequences of superstring-inspired models with intermediate-mass scales

    International Nuclear Information System (INIS)

    Gabbiani, F.

    1987-01-01

    The phenomenological consequences of implementing intermediate-mass scales in E 6 superstring-inspired models are discussed. Starting from a suitable Calabi-Yau compactification with b 1,1 >1, one gets, after Hosotani breaking, the rank r=5 gauge group SU(3) C x SU(2) L x U(1) Y x U(1) E , that is broken at an intermediate-mass scale down to the standard-model group. The analysis of both the intermediate and the electroweak breaking is performed in the two cases Λ c = M x and Λ c x , where Λ c is the scale at which the hidden sector gauginos condensate. It is performed quantitatively the minimization of the low-energy effective potential and the renormalization group analysis, yielding a viable set of mass spectra and confirming the reliability of the intermediate-breaking scheme

  4. Pion double charge exchange

    International Nuclear Information System (INIS)

    Cooper, M.D.

    1978-01-01

    The pion double charge exchange data on the oxygen isotopes is reviewed and new data on 9 Be, 12 C, 24 Mg, and 28 Si are presented. Where theoretical calculations exist, they are compared to the data. 9 references

  5. Pion in a box

    International Nuclear Information System (INIS)

    Bietenholz, W.; Rakow, P.E.L.; Schierholz, G.; Regensburg Univ.

    2010-02-01

    The residual mass of the pion in a finite spatial box at vanishing quark masses is computed with two flavors of dynamical clover fermions. The result is compared with predictions of chiral perturbation theory in the δ regime. (orig.)

  6. Pion production in nuclei

    International Nuclear Information System (INIS)

    Afnan, I.R.; Thomas, A.W.

    1976-01-01

    A method has been suggested for relating μ-capture in nuclei to pion absorption through partially conserved axial vector current hypothesis. The success of the method relies heavily on the knowledge of the pion absorption amplitude at a momentum transfer equal to the μ-meson mass. That is we need to know the pion absorption amplitude off the mass-shell. The simplest nucleus for which this suggestion can be examined is μ-capture in deuterium. The Koltum-Reitan model is used to determine the pion absorption amplitude off the mass shell. In particular the senstivity of this off-mass-shell extrapolution to details of the N-N interaction is studied. (author)

  7. Status of PILAC: A pion linac facility for 1-GeV pion physics at LAMPF

    International Nuclear Information System (INIS)

    Thiessen, H.A.

    1990-01-01

    A Pion Linac (PILAC) is being designed for LAMPF. Together with its high resolution beam line and spectrometer, the system is optimized to provide 10 9 pions per second on target and 200-keV resolution for the (π + ,K + ) reaction at 920, MeV. There will also be an achromatic beam line capable of utilizing the maximum energy available, thus opening up the possibility of a broad experimental program as is being discussed at this workshop. 12 figs

  8. The electric conductivity of a pion gas

    International Nuclear Information System (INIS)

    Atchison, J.; Rapp, R.

    2017-01-01

    The determination of transport coefficients plays a central role in characterizing hot and dense nuclear matter. In the present work we calculate the electric conductivity of hot hadronic matter by extracting it from the ρ meson spectral function, as its zero-energy limit at vanishing momentum. Using hadronic many-body theory, we calculate the ρ meson self-energy in a pion gas. This requires the dressing of the pion propagators in the ρ self-energy with π - ρ loops, and the inclusion of vertex corrections to maintain gauge invariance. The resulting spectral function is used to calculate the electric conductivity of hot hadronic matter. In particular, we analyze the transport peak of the spectral function and extract its behavior with temperature and coupling strength. Our results suggest that, while obeying lower bounds proposed by conformal field theories in the strong-coupling limit, hot pion matter is a strongly-coupled medium. (paper)

  9. Transverse energy and neutral pion spectra obtained from 16O- and 32S-induced reactions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    Plasil, F.; Albrecht, R.; Awes, T.C.

    1989-01-01

    The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The most promising indication that this may, in fact, be the case comes from the NA38 dimuon measurements, which are focused on the question of J//psi/ suppression. This effect was predicted to be one of the signatures of QGP formation before any measurements were made, and it is the subject of the two other talks at this conference that deal with nucleus-nucleus reactions at ultrarelativistic energies. In this presentation we consider the general (global) features of heavy-ion reactions at CERN energies, and we examine the degree to which they differ from mere superpositions of nucleon-nucleon collisions. We discuss the present status of our data analysis and our main conclusions from the first round of CERN experiments with emphasis on transverse energy measurements, on attained energy densities, and on the spectra of produced neutral pions. Because of time limitations we will not discuss our measurements of distributions of charged particles and the analysis of these distributions in terms of fluctuations nor the results that we have obtained with the Plastic Ball on the behavior of target spectator matter. 20 refs., 5 figs

  10. Some applications of the multiple scattering theory to the study of the hadron-nucleus interactions at intermediate energies

    International Nuclear Information System (INIS)

    Dedonder, J.-P.

    1979-01-01

    This work is devoted to the study of elastic hadron nucleus scattering. At first, an asymptotic evaluation leads to a closed, analytic expression of the eikonal amplitude. This approximate expression displays the role and the influence of the nuclear paremeters in, e.g., p-nucleus scattering around 1 GeV. Pion-nucleus scattering around the 3-3 resonance is then studied. A 3 body model calculation (pion, bound nucleon and residual nucleus represented by a potential) allows to study the importance of binding effects in this problem dominated by the strong energy dependence of the elementary amplitude. The last part is devoted to the construction in momentum space of a realistic optical potential and its comparison with experimental data. The scalling of π + and π - on neighbouring isotopes should allow the measure of the differences between the proton and neutron distributions in nuclei [fr

  11. Elliptic flow of charged pions, protons and strange particles emitted in Pb+Au collisions at top SPS energy

    CERN Document Server

    Adamova, D.; Andronic, A.; Antonczyk, D.; Appelshauser, H.; Belaga, V.; Bielcikova, J.; Braun-Munzinger, P.; Busch, O.; Cherlin, A.; Damjanovic, S.; Dietel, T.; Dietrich, L.; Drees, A.; Dubitzky, W.; Esumi, S.I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glassel, P.; Hering, G.; Holeczek, J.; Kalisky, M.; Krobath, G.; Kushpil, V.; Maas, A.; Marin, A.; Milosevic, J.; Miskowiec, D.; Panebrattsev, Y.; Petchenova, O.; Petracek, V.; Radomski, S.; Rak, J.; Ravinovich, I.; Rehak, P.; Sako, H.; Schmitz, W.; Schuchmann, S.; Sedykh, S.; Shimansky, S.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, I.; Tsiledakis, G.; Wessels, J.P.; Wienold, T.; Wurm, J.P.; Yurevich, S.; Yurevich, V.

    2012-01-01

    Differential elliptic flow spectra v2(pT) of \\pi-, K0short, p, \\Lambda were measured at \\sqrt(s NN)= 17.3 GeV around midrapidity by the CERN-CERES/NA45 experiment in mid-central Pb+Au collisions (10% of \\sigma(geo)). The pT range extends from about 0.1 GeV/c (0.55 GeV/c for \\Lambda ) to more than 2 GeV/c. The proton v2(pT) is extracted from the sample of \\pi+ candidates using particle ratios from NA49 adapted to CERES acceptance and analysis cuts. The v2(pT) spectra are compared to ideal-hydrodynamics calculations. In synopsis, v2 in the series \\pi- - K0short - p - \\Lambda is seen to fall towards low pT increasingly below the hydro calculations even for kinetic freeze-out at Tf= 160 MeV which effectively suppress the hadronic evolution. The proton v2(pT) shows a downward swing towards low pT with excursions into negative values; the possible impact of a pion-flow isospin asymmetry observed by STAR at RHIC is found not to alter these conclusions. Results are discussed in perspective of recent viscous hydrodyna...

  12. A hadron-nucleus collision event generator for simulations at intermediate energies

    CERN Document Server

    Ackerstaff, K; Bollmann, R

    2002-01-01

    Several available codes for hadronic event generation and shower simulation are discussed and their predictions are compared to experimental data in order to obtain a satisfactory description of hadronic processes in Monte Carlo studies of detector systems for medium energy experiments. The most reasonable description is found for the intra-nuclear-cascade (INC) model of Bertini which employs microscopic description of the INC, taking into account elastic and inelastic pion-nucleon and nucleon-nucleon scattering. The isobar model of Sternheimer and Lindenbaum is used to simulate the inelastic elementary collisions inside the nucleus via formation and decay of the DELTA sub 3 sub 3 -resonance which, however, limits the model at higher energies. To overcome this limitation, the INC model has been extended by using the resonance model of the HADRIN code, considering all resonances in elementary collisions contributing more than 2% to the total cross-section up to kinetic energies of 5 GeV. In addition, angular d...

  13. Knock out for subthreshold pion production

    International Nuclear Information System (INIS)

    Guet, C.; Prakash, M.

    1984-05-01

    The contribution of nucleon-nucleon-single collisions to subthreshold pion production in hadron-nucleus and nucleus-nucleus collisions, Esub(Lab) < 300 A MeV is investigated within a knock-out type model. This contribution might be important for energies higher than about 150 MeV/nucleon but decrease strongly with decreasing beam energy

  14. Two-pion production in photon-induced reactions

    Indian Academy of Sciences (India)

    A deeper understanding of the situation is anticipated from a detailed experimental study of meson photoproduction from nuclei in exclusive reactions. In the energy regime above the (1232) resonance, the dominant double pion production channels are of particular interest. Double pion photoproduction from nuclei is ...

  15. Where to look for pion condensation in heavy ion collisions

    International Nuclear Information System (INIS)

    Pirner, H.J.

    1994-08-01

    The possibility to observe a pion condensate in peripheral nucleus-nucleus collisions at GSI energies is discussed. A condensate may be observed via pronounced peaks in pion production in a narrow region of momenta k perpendicular to ≅(2-3)m π corresponding to rather large rapidity values. (orig.)

  16. Design and simulation of the nuSTORM pion beamline

    Energy Technology Data Exchange (ETDEWEB)

    Liu, A., E-mail: aoliu@fnal.gov; Neuffer, D.; Bross, A.

    2015-11-21

    The nuSTORM (neutrinos from STORed Muons) proposal presents a detailed design for a neutrino facility based on a muon storage ring, with muon decay in the production straight section of the ring providing well defined neutrino beams. The facility includes a primary high-energy proton beam line, a target station with pion production and collection, and a pion beamline for pion transportation and injection into a muon decay ring. The nuSTORM design uses “stochastic injection”, in which pions are directed by a chicane, referred to as the Orbit Combination Section (OCS), into the production straight section of the storage ring. Pions that decay within that straight section provide muons within the circulating acceptance of the ring. The design enables injection without kickers or a separate pion decay transport line. The beam line that the pions traverse before being extracted from the decay ring is referred to as the pion beamline. This paper describes the design and simulation of the pion beamline, and includes full beam dynamics simulations of the system.

  17. [Intermediate energy studies of polarization transfer, polarized deuteron scattering, and (p,π+-) reactions: Rapporteur's report

    International Nuclear Information System (INIS)

    Moss, J.M.

    1985-01-01

    An overview of intermediate energy (80 to 1000 MeV) study contributions to the International Polarization Symposium in Osaka, Japan, August 1985 is presented in this report. Contributions fall into three categories: polarization transfer, polarized deuteron scattering and polarized (p,π +- ) reactions

  18. Angular dependences of the tensor analyzing powers in the dd→3Hen reaction at intermediate energies

    International Nuclear Information System (INIS)

    Ladygin, V.P.; Ladygina, N.B.

    2002-01-01

    The tensor analyzing powers A yy , A xx , and A xz in the dd→ 3 Hen reaction at intermediate energies are considered in the framework of the one-nucleon-exchange approximation. Their strong sensitivity to the 3 He and deuteron spin structure at short distances is shown

  19. Ionization of multielectronic atoms by proton impact at high and intermediate energies

    International Nuclear Information System (INIS)

    Fainstein, P.D.; Ponce, V.H.; Rivarola, R.D.

    1988-01-01

    In this work, it is studied Ne ionization by proton impact at high and intermediate energies using the CDW-EIS model. Calculations on simple and double differential cross sections are presented. The results are compared to available experimental data. (A.C.A.S.) [pt

  20. Measurement of the charged-pion polarizability.

    Science.gov (United States)

    Adolph, C; Akhunzyanov, R; Alexeev, M G; Alexeev, G D; Amoroso, A; Andrieux, V; Anosov, V; Austregesilo, A; Badełek, B; Balestra, F; Barth, J; Baum, G; Beck, R; Bedfer, Y; Berlin, A; Bernhard, J; Bicker, K; Bieling, J; Birsa, R; Bisplinghoff, J; Bodlak, M; Boer, M; Bordalo, P; Bradamante, F; Braun, C; Bressan, A; Büchele, M; Burtin, E; Capozza, L; Chiosso, M; Chung, S U; Cicuttin, A; Colantoni, M; Crespo, M L; Curiel, Q; Dalla Torre, S; Dasgupta, S S; Dasgupta, S; Denisov, O Yu; Dinkelbach, A M; Donskov, S V; Doshita, N; Duic, V; Dünnweber, W; Dziewiecki, M; Efremov, A; Elia, C; Eversheim, P D; Eyrich, W; Faessler, M; Ferrero, A; Filin, A; Finger, M; Finger, M; Fischer, H; Franco, C; du Fresne von Hohenesche, N; Friedrich, J M; Frolov, V; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S; Geyer, R; Gnesi, I; Gobbo, B; Goertz, S; Gorzellik, M; Grabmüller, S; Grasso, A; Grube, B; Grussenmeyer, T; Guskov, A; Guthörl, T; Haas, F; von Harrach, D; Hahne, D; Hashimoto, R; Heinsius, F H; Herrmann, F; Hinterberger, F; Höppner, Ch; Horikawa, N; d'Hose, N; Huber, S; Ishimoto, S; Ivanov, A; Ivanshin, Yu; Iwata, T; Jahn, R; Jary, V; Jasinski, P; Jörg, P; Joosten, R; Kabuss, E; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Kisselev, Yu; Klein, F; Klimaszewski, K; Koivuniemi, J H; Kolosov, V N; Kondo, K; Königsmann, K; Konorov, I; Konstantinov, V F; Kotzinian, A M; Kouznetsov, O; Krämer, M; Kroumchtein, Z V; Kuchinski, N; Kuhn, R; Kunne, F; Kurek, K; Kurjata, R P; Lednev, A A; Lehmann, A; Levillain, M; Levorato, S; Lichtenstadt, J; Maggiora, A; Magnon, A; Makke, N; Mallot, G K; Marchand, C; Martin, A; Marzec, J; Matousek, J; Matsuda, H; Matsuda, T; Meshcheryakov, G; Meyer, W; Michigami, T; Mikhailov, Yu V; Miyachi, Y; Moinester, M A; Nagaytsev, A; Nagel, T; Nerling, F; Neubert, S; Neyret, D; Nikolaenko, V I; Novy, J; Nowak, W-D; Nunes, A S; Olshevsky, A G; Orlov, I; Ostrick, M; Panknin, R; Panzieri, D; Parsamyan, B; Paul, S; Peshekhonov, D; Platchkov, S; Pochodzalla, J; Polyakov, V A; Pretz, J; Quaresma, M; Quintans, C; Ramos, S; Regali, C; Reicherz, G; Rocco, E; Rossiyskaya, N S; Ryabchikov, D I; Rychter, A; Samoylenko, V D; Sandacz, A; Sarkar, S; Savin, I A; Sbrizzai, G; Schiavon, P; Schill, C; Schlüter, T; Schmidt, K; Schmieden, H; Schönning, K; Schopferer, S; Schott, M; Shevchenko, O Yu; Silva, L; Sinha, L; Sirtl, S; Slunecka, M; Sosio, S; Sozzi, F; Srnka, A; Steiger, L; Stolarski, M; Sulc, M; Sulej, R; Suzuki, H; Szabelski, A; Szameitat, T; Sznajder, P; Takekawa, S; ter Wolbeek, J; Tessaro, S; Tessarotto, F; Thibaud, F; Uhl, S; Uman, I; Virius, M; Wang, L; Weisrock, T; Wilfert, M; Windmolders, R; Wollny, H; Zaremba, K; Zavertyaev, M; Zemlyanichkina, E; Ziembicki, M; Zink, A

    2015-02-13

    The COMPASS collaboration at CERN has investigated pion Compton scattering, π(-)γ→π(-)γ, at center-of-mass energy below 3.5 pion masses. The process is embedded in the reaction π(-)Ni→π(-)γNi, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasireal photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, Q(2)<0.0015  (GeV/c)(2). From a sample of 63,000 events, the pion electric polarizability is determined to be α(π)=(2.0±0.6(stat)±0.7(syst))×10(-4)  fm(3) under the assumption α(π)=-β(π), which relates the electric and magnetic dipole polarizabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is found in agreement with the expectation from chiral perturbation theory. An additional measurement replacing pions by muons, for which the cross-section behavior is unambiguously known, was performed for an independent estimate of the systematic uncertainty.

  1. Precision measurements of pion nucleon elastic scattering in the P3 energy region at LAMPF. 1984 progress report

    International Nuclear Information System (INIS)

    Sadler, M.E.

    1984-01-01

    This study is a continuation of the pion-nucleon program at the Los Alamos Meson Physics Facility. Previous measurements, in chronological order, have included differential cross sections for π/sup +-/p elastic scattering at P/sub π/ = 378 - 687 MeV/c (LAMPF experiment 363), π - p charge exchange for P/sub π/ = 247 - 687 MeV/c (LAMPF experiment 120), and measurements of the polarization asymmetry for π/sup +-/p -> π/sup +-/p and π - p -> π 0 n for P/sub π/ = 471 - 687 MeV/c (LAMPF experiments 120* and 120**, respectively). Two experiments were initiated in the past year, forward-angle differential cross sections for π - p -> π 0 n at P/sub π/ = 96 - 150 MeV/c (LAMPF experiment 809) and polarization asymmetry for π - p - > γn (LAMPF experiment 804). Approved experiments which will be scheduled in the future are spin rotation measurements for π/sup +-/p -> π/sup +-/p (LAMPF experiments 806 and 807) and differential cross sections for π - p -> π 0 n near 0 0 and 180 0 at P/sub π/ = 471-687 MeV/c (LAMPF experiment 849). Another experiment, differential cross section measurements for π/sup +-/ elastic scattering on 3 He and 3 H (LAMPF experiment 546), has also been completed. The 3 He and 3 H targets form an isospin doublet analogous to the proton and neutron. The I 3 = -1/2 member ( 3 H) of the multiplet can be utilized as a target in this case, allowing a direct test of charge symmetry not achievable in the πN system due to the impossibility of a pure neutron target

  2. Pion-nucleus forward scattering amplitudes at Δ(3,3) energies for π+---12C, 40Ca and 48Ca

    International Nuclear Information System (INIS)

    Dragoset, W.H. Jr.

    1978-01-01

    Using the LAMPF P 3 channel, small angle elastic cross sections and total cross sections were measured for π +- -- 12 C, 40 Ca and 48 Ca at incident pion kinetic energies spanning the energy region of the Δ(3,3) resonance. The sigma/sub EL/ experiment employed a spectrometer consisting of two magnets and six MWPC to measure scattering angles and momenta. For the sigma/sub T/ experiment six MWPC were positioned about the target in the beam to measure the deflection or absorption of the incident pions. Both experiments monitored the Jacobian cusp of the π → μ + ν decay to achieve absolute normalization. The two complementary data sets allowed the nuclear forward scattering amplitudes, f/sub N/(0), to be completely determined. The sigma/sub EL/ data were fit by a phenomenological small angle scattering model developed by Bethe and modified by West and Yennie. Due to the presence of nuclear-Coulomb interference in the elastic cross sections, both the magnitude and sign of Re f/sub N/ were determined by the fits. The Re f/sub N/ results were used in the sigma/sub T/ analysis to calculate corrections for the nuclear and nuclear-Coulomb interference amplitudes. Im f/sub N/ was calculated from the sigma/sub T/ results via the optical theorem. The overall self-consistencies of the data were checked by inserting IM f/sub N/ as a fixed parameter into the sigma/sub EL/ fits and comparing the resulting Re f/sub N/ to the original Re f/sub N/. It was determined that Re f/sub N/(0) has a zero near 180 MeV for both 12 C and 40 Ca. For 48 Ca, however, the Re f/sub N/ obtained by fitting with the West-Yennie formula was quite charge dependent and did not exhibit a zero in the energy range investigated. The differences in the 40 Ca, 48 Ca total cross sections were compared to a simple Kisslinger optical model calculation. The model indicated that the RMS neutron radius of 48 Ca exceeds the proton radius by 0.10 +- 0.06 fm

  3. Intermediate steps towards the 2000-Watt society in Switzerland: an energy-economic scenario analysis

    International Nuclear Information System (INIS)

    Schulz, T. F.

    2007-01-01

    In this dissertation by Thorsten Frank Schulz the intermediate steps necessary to realise the 2000-Watt Society in Switzerland are examined. An analysis of an energy-economic scenario shows that the 2000-Watt Society should be seen as a long-term goal. According to the author, the major changes required to allow the implementation of this project concern energy-transformation and energy-demand technologies. Electricity will, according to the author, play an important role in a service-oriented society in the future. In such a transformation even intermediate steps are associated with considerable expense. The aims of the 2000-Watt Society project are listed. Energy and CO 2 balances for the domestic and transport sectors are presented and discussed. Complementary analyses are presented concerning fuel cells and wood-based fuel technologies. Finally, the implications of the 2000-Watt society and the effects of technological change are summarised and an outlook is presented

  4. Energy-momentum tensor of intermediate vector bosons in an external electromagnetic field

    International Nuclear Information System (INIS)

    Mostepanenko, V.M.; Sokolov, I.Yu.

    1988-01-01

    Expressions are obtained for the canonical and metric energy-momentum tensors of the vector field of intermediate bosons in an external electromagnetic field. It is shown that in the case of a gyromagnetic ratio not equal to unity the energy-momentum tensor cannot be symmetrized on its indices, and an additional term proportional to the anomalous magnetic moment appears in the conservation laws. A modification of the canonical formalism for scalar and vector fields in an external field is proposed in accordance with which the Hamiltonian density is equal to the 00 component of the energy-momentum tensor. An expression for the energy-momentum tensor of a closed system containing a gauge field of intermediate bosons and an electromagnetic field is obtained

  5. Pion-exchange contribution to the parity-violating asymmetry in pp scattering

    International Nuclear Information System (INIS)

    Silbar, R.R.; Kloet, W.M.; Kisslinger, L.S.; Dubach, J.

    1988-01-01

    Charged pion exchange, producing nΔ ++ intermediate states, contributes negatively to the weak scattering asymmetry in longitudinally-polarized pp scattering. Including this contribution moves the theoretical prediction away from the 800 MeV experimental datum. The pion-exchange contribution has both inelastic and elastic scattering components and is sizeable even below the pion production threshold. Strong distortions enhance the magnitude of the effect. 14 refs., 5 figs

  6. Fragment mass distribution of proton-induced spallation reaction with intermediate energy

    International Nuclear Information System (INIS)

    Fan Sheng; Ye Yanlin; Xu Chuncheng; Chen Tao; Sobolevsky, N.M.

    2000-01-01

    The test of part benchmark of SHIELD code is finished. The fragment cross section and mass distribution and excitation function of the residual nuclei from proton-induced spallation reaction on thin Pb target with intermediate energy have been calculated by SHIELD code. And the results are in good agreement with measured data. The fragment mass distribution of the residual nuclei from proton-induced spallation reaction on thick Pb target with incident energy 1.6 GeV have been simulated

  7. Spin observables in inelastic proton-nucleus scattering at intermediate energy

    International Nuclear Information System (INIS)

    Smith, R.D.

    1984-01-01

    This dissertation is a study of spin observables in inelastic proton-nucleus reactions for incident proton energies near 1 GeV. At this energy, the dominant reaction mechanisms are (1) quasi-free knockout of one or more nucleons, and (2) pion production through the Δ resonance. The cross section due to quasi-free knockout can be reasonably well understood theoretically in a multiple scattering picture, which uses measured NN amplitudes as input. Calculations of this sort were carried out in reference [10] using scalar NN amplitudes parameterized as Gaussians. The author has extended this picture to include spin dependent NN amplitudes. This allows calculation of all the spin observables, Ay, DLL, DSS, DNN, DLS, and DSL, as well as the cross section dsigma/dOmegadp due to quasi-free knockout of one or more particles. The cross section and polarization Ay have been measured at the LAMPF High Resolution Spectrometer at T/sub L/ = 800 MeV on 12 C. The theoretical results agree well with the data in the quasi-free region. The results for the remaining spin observables provide predictions for experiments which can be performed at LAMPF. By comparing the calculations with the data, it may be possible to separate the contribution due to a quasi-free knockout, and see a signature of quasi-free Δ production in the spin observables

  8. Electro- and photonuclear physics at intermediate energies: Saclay activities since 1970 and future prospects

    International Nuclear Information System (INIS)

    Schuhl, C.

    1981-06-01

    A review of experiments performed at the 600 MeV electron linear accelerator with electron, photon, pion and muon beams is reported and it is shown the long range perspective of nuclear physics in that domain

  9. The energy-deposition model. Electron loss of heavy ions in collisions with neutral atoms at low and intermediate energies

    International Nuclear Information System (INIS)

    Shevelko, V.P.; Litsarev, M.S.; Kato, D.; Tawara, H.

    2010-09-01

    Single- and multiple-electron loss processes in collisions of heavy many-electron ions (positive and negative) in collisions with neutral atoms at low and intermediate energies are considered using the energy-deposition model. The DEPOSIT computer code, created earlier to calculate electron-loss cross sections at high projectile energies, is extended for low and intermediate energies. A description of a new version of DEPOSIT code is given, and the limits of validity for collision velocity in the model are discussed. Calculated electron-loss cross sections for heavy ions and atoms (N + , Ar + , Xe + , U + , U 28+ , W, W + , Ge - , Au - ), colliding with neutral atoms (He, Ne, Ar, W) are compared with available experimental and theoretical data at energies E > 10 keV/u. It is found that in most cases the agreement between experimental data and the present model is within a factor of 2. Combining results obtained by the DEPOSIT code at low and intermediate energies with those by the LOSS-R code at high energies (relativistic Born approximation), recommended electron-loss cross sections in a wide range of collision energy are presented. (author)

  10. Effective pion--nucleon interaction in nuclear matter

    International Nuclear Information System (INIS)

    Celenza, L.S.; Liu, L.C.; Nutt, W.; Shakin, C.M.

    1976-01-01

    We discuss the modification of the interaction between a pion and a nucleon in the presence of an infinite medium of nucleons (nuclear matter). The theory presented here is covariant and is relevant to the calculation of the pion--nucleus optical potential. The specific effects considered are the modifications of the nucleon propagator due to the Pauli principle and the modification of the pion and nucleon propagators due to collisions with nucleons of the medium. We also discuss in detail the pion self-energy in the medium, paying close attention to off-shell effects. These latter effects are particularly important because of the rapid variation with energy of the fundamental pion--nucleon interaction. Numerical results are presented, the main feature being the appearance of a significant damping width for the (3, 3) resonance

  11. Pion radiation for high grade astrocytoma: results of a randomized study

    International Nuclear Information System (INIS)

    Pickles, Tom; Goodman, George B.; Rheaume, Dorianne E.; Duncan, Graeme G.; Fryer, Chris J.; Bhimji, Shamim; Ludgate, Charles; Syndikus, Isabel; Graham, Peter; Dimitrov, Mario; Bowen, Julie

    1997-01-01

    Purpose: This study attempted to compare within a randomized study the outcome of pion radiation therapy vs. conventional photon irradiation for the treatment of high-grade astrocytomas. Methods and Materials: Eighty-four patients were randomized to pion therapy (33-34.5 Gyπ), or conventional photon irradiation (60 Gy). Entry criteria included astrocytoma (modified Kernohan high Grade 3 or Grade 4), age 18-70, Karnofsky performance status (KPS) ≥50, ability to start irradiation within 30 days of surgery, unifocal tumor, and treatment volume < 850 cc. The high-dose volume in both arms was computed tomography enhancement plus a 2-cm margin. The study was designed with the power to detect a twofold difference between arms. Results: Eighty-one eligible patients were equally balanced for all known prognostic variables. Pion patients started radiation 7 days earlier on average than photon patients, but other treatment-related variables did not differ. There were no significant differences for either early or late radiation toxicity between treatment arms. Actuarial survival analysis shows no differences in terms of time to local recurrence or overall survival where median survival was 10 months in both arms (p = 0.22). The physician-assessed KPS and patient-assessed quality of life (QOL) measurements were generally maintained within 10 percentage points until shortly before tumor recurrence. There was no apparent difference in the serial KPS or QOL scores between treatment arms. Conclusion: In contrast to high linear energy transfer (LET) therapy for central nervous system tumors, such as neutron or neon therapy, the safety of pion therapy, which is of intermediate LET, has been reaffirmed. However, this study has demonstrated no therapeutic gain for pion therapy of glioblastoma

  12. MCNP6 Simulation of Light and Medium Nuclei Fragmentation at Intermediate Energies

    Energy Technology Data Exchange (ETDEWEB)

    Mashnik, Stepan Georgievich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kerby, Leslie Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of Idaho, Moscow, ID (United States)

    2015-08-24

    Fragmentation reactions induced on light and medium nuclei by protons and light nuclei of energies around 1 GeV/nucleon and below are studied with the Los Alamos transport code MCNP6 and with its CEM03.03 and LAQGSM03.03 event generators. CEM and LAQGSM assume that intermediate-energy fragmentation reactions on light nuclei occur generally in two stages. The first stage is the intranuclear cascade (INC), followed by the second, Fermi breakup disintegration of light excited residual nuclei produced after the INC. CEM and LAQGSM account also for coalescence of light fragments (complex particles) up to sup>4He from energetic nucleons emitted during INC. We investigate the validity and performance of MCNP6, CEM, and LAQGSM in simulating fragmentation reactions at intermediate energies and discuss possible ways of further improving these codes.

  13. Study of the incident pion deflection in passing through atomic nucleus

    International Nuclear Information System (INIS)

    Strugalski, Z.; Pawlak, T.; Pluta, J.

    1982-01-01

    Pion-xenon nucleus collision events at 3.5 GeV/c momentum are studied in which the incident pion is deflected only, without particle production; the deflection is accompanied by emission of nucleons. The multiplicity of the protons emitted is a measure of the nuclear matter layer thickness passed by the pion. It can be concluded that: a) a definite simple relation exists between the pion deflection angle and the thickness of the nuclear matter layer traversed by this pion; b) the deflection angle of the incident pion increases in a definite manner with increasing the thickness of the nuclear matter layer traversed by this pion; c) the average kinetic energy, average longitudinal momentum and average transverse momentum of the protons emitted do not depend on the pion deflection angle

  14. Charge dependence of the pion-nucleon coupling constant

    Directory of Open Access Journals (Sweden)

    V. A. Babenko

    2015-07-01

    Full Text Available On the basis of the Yukawa potential we study the pion-nucleon coupling constants for the neutral and charged pions assuming that nuclear forces at low energies are mainly determined by the exchange of virtual pions. We obtain the charged pseudovector pion-nucleon coupling constant f2π± = 0.0804(7 by making the use of experimental low-energy scattering parameters for the singlet pp- and np-scattering, and also by use of the neutral pseudovector pion-nucleon coupling constant f2π0 = 0.0749(7. Corresponding value of the charged pseudoscalar pion-nucleon coupling constant g2π0 / 4π = 14.55(13 is also determined. This calculated value of the charged pseudoscalar pion-nucleon coupling constant is in fully agreement with the experimental constant g2π0 / 4π = 14.52(26 obtained by the Uppsala Neutron Research Group. Our results show considerable charge splitting of the pion-nucleon coupling constant.

  15. Pion double charge exchange in the Δ33 resonance region

    International Nuclear Information System (INIS)

    Wirzba, A.; Toki, H.; Siciliano, E.R.; Johnson, M.B.; Gilman, R.

    1989-01-01

    We examine the model dependence and nuclear-structure sensitivity of several Δ 33 -dominated processes contributing to pion double charge exchange on nuclei in the region of the Δ 33 resonance. These processes include the Δ 33 -nucleon interaction V NΔ and sequential scattering, in which the pion undergoes single charge exchange on two different nucleons. In all cases, the scattering takes place through the exchange of an intermediate π and ρ meson. Sequential-mediated double charge exchange is found to be only moderately sensitive to short-range correlations, meson-nucleon form factors, and the rho meson, whereas V NΔ -mediated double charge exchange is very sensitive to all these effects. Results are given for double charge exchange on 18 O (double isobaric analog transitions) and 16 O (nonanalog transitions). Sequential double charge exchange is shown to favor non-spin-flip matrix elements of the transition operator whereas V NΔ -mediated double charge exchange favors spin-flip matrix elements. The energy dependence of the zero-degree cross sections for V NΔ and sequential scattering are also different: Sequential tends to increase monotonically from 100 to 300 MeV, whereas V NΔ peaks at about 150 MeV. The delta-nucleon interaction is found likely to dominate over sequential scattering in nonanalog double charge exchange. The V NΔ is also large in analog double charge exchange, but it does not enable us to explain the anomalous behavior of the 18 O differential cross sections

  16. Tensor polarization in pion-deuteron elastic scattering

    International Nuclear Information System (INIS)

    Holt, R.J.; Freeman, W.S.; Geesaman, D.F.

    1985-01-01

    During this year the analysis of measurements of t 20 in π-d elastic scattering was completed and a final summary manuscript was prepared for publication. The results consists of angular distributions of the deuteron tensor polarization in π-d elastic scattering at pion energies of 140, 180, 220 and 256 MeV. Theoretical calculations in which the effects of pion absorption on the elastic channel are small reproduce the data. No rapid angular or energy dependence was found near a pion energy of 134 MeV, where another experiment at SIN has suggested the existence of dibaryon resonances

  17. Forward pion-nucleon charge exchange reaction and Regge constraints

    International Nuclear Information System (INIS)

    Huang Fei; Sibirtsev, A.; Krewald, S.; Hanhart, C.; Haidenbauer, J.; Meibner, U.-G.

    2009-01-01

    We present our recent study of pion-nucleon charge exchange amplitudes above 2 GeV. We analyze the forward pion-nucleon charge exchange reaction data in a Regge model and compare the resulting amplitudes with those from the Karlsruhe-Helsinki and George-Washington-University partial-wave analyses. We explore possible high-energy constraints for theoretical baryon resonance analyses in the energy region above 2 GeV. Our results show that for the pion-nucleon charge exchange reaction, the appropriate energy region for matching meson-nucleon dynamics to diffractive scattering should be around 3 GeV for the helicity flip amplitude. (authors)

  18. Pion-induced damage in silicon detectors

    CERN Document Server

    Bates, S; Glaser, M; Lemeilleur, F; León-Florián, E; Gössling, C; Kaiser, B; Rolf, A; Wunstorf, R; Feick, H; Fretwurst, E; Lindström, G; Moll, Michael; Taylor, G; Chilingarov, A G

    1995-01-01

    The damage induced by pions in silicon detectors is studied for positive and negative pions for fluence up to 10(14)cm-2 and 10(13) cm-2 respectively. Results on the energy dependence of the damage in the region of 65-330 MeV near to the  resonance are presented. The change in detector characteristics such as leakage current, charge collection efficiency and effective impurity concentration including long-term annealing effects have been studied. Comparisons to neutron and proton-induced damage are presented and discussed.

  19. The structure of nuclear states at low, intermediate and high excitation energies

    International Nuclear Information System (INIS)

    Soloviev, V.G.

    1976-01-01

    It is shown that within the model based on the quasiparticle-phonon interaction one can obtain the description of few-quasiparticle components of nuclear states at low, intermediate and high excitation energies. For the low-lying states the energy of each level is calculated. The few-quasiparticle components at intermediate and high excitation energies are represented to be averaged in certain energy intervals and their characteri stics are given as the corresponding strength functions. The fragmentation of single-particle states in deformed nuclei is studied. It is shown that in the distribution of the single-particle strength alongside with a large maximum there appear local maxima and the distribution itself has a long tail. The dependence of neutron strength functions on the excitation energy is investigated for the transfer reaction of the type (d,p) and (d,t). The s,- p,- and d-wave neutron strength functions are calculated at the neutron binding energy Bn. A satisfactory agreement with experiment is obtained. The energies and Elambda-strength functions for giant multipole resonances in deformed nuclei are calculated. The energies of giant quadrupole and octupole resonances are calculated. Their widths and fine structure are being studied. It is stated that to study the structure of highly excited states it is necessary to find the values of many-quasiparticle components of the wave functions. The ways of experimental determination of these components based on the study of γ-transitions between highly excited states are discussed

  20. Pions to Quarks

    Science.gov (United States)

    Brown, Laurie Mark; Dresden, Max; Hoddeson, Lillian

    2009-01-01

    Part I. Introduction; 1. Pions to quarks: particle physics in the 1950s Laurie M Brown, Max Dresden and Lillian Hoddeson; 2. Particle physics in the early 1950s Chen Ning Yang; 3. An historian's interest in particle physics J. L. Heilbron; Part II. Particle discoveries in cosmic rays; 4. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957 George D. Rochester; 5. Cosmic-ray work with emulsions in the 1940s and 1950s Donald H. Perkins; Part III. High-energy nuclear physics; Learning about nucleon resonances with pion photoproduction Robert L. Walker; 7. A personal view of nucleon structure as revealed by electron scattering Robert Hofstadter; 8. Comments on electromagnetic form factors of the nucleon Robert G. Sachs and Kameshwar C. Wali; Part IV. The new laboratory; 9. The making of an accelerator physicist Matthew Sands; 10. Accelerator design and construction in the 1950s John P. Blewett; 11. Early history of the Cosmotron and AGS Ernest D. Courant; 12. Panel on accelerators and detectors in the 1950s Lawrence W. Jones, Luis W. Alvarez, Ugo Amaldi, Robert Hofstadter, Donald W. Kerst, Robert R. Wilson; 13. Accelerators and the Midwestern Universities Research Association in the 1950s Donald W. Kerst; 14. Bubbles, sparks and the postwar laboratory Peter Galison; 15. Development of the discharge (spark) chamber in Japan in the 1950s Shuji Fukui; 16. Early work at the Bevatron: a personal account Gerson Goldhaber; 17. The discovery of the antiproton Owen Chamberlain; 18. On the antiproton discovery Oreste Piccioni; Part V. The Strange Particles; 19. The hydrogen bubble chamber and the strange resonances Luis W. Alvarez; 20. A particular view of particle physics in the fifties Jack Steinberger; 21. Strange particles William Chinowsky; 22. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers William B. Fowler; 23. From the 1940s into the 1950s Abraham Pais; Part VI. Detection of the

  1. Accuracy estimation for intermediate and low energy neutron transport calculation with Monte Carlo code MCNP

    International Nuclear Information System (INIS)

    Kotegawa, Hiroshi; Sasamoto, Nobuo; Tanaka, Shun-ichi

    1987-02-01

    Both ''measured radioactive inventory due to neutron activation in the shield concrete of JPDR'' and ''measured intermediate and low energy neutron spectra penetrating through a graphite sphere'' are analyzed using a continuous energy model Monte Carlo code MCNP so as to estimate calculational accuracy of the code for neutron transport in thermal and epithermal energy regions. Analyses reveal that MCNP calculates thermal neutron spectra fairly accurately, while it apparently over-estimates epithermal neutron spectra (of approximate 1/E distribution) as compared with the measurements. (author)

  2. Differential cross sections for electron-impact vibrational-excitation of tetrahydrofuran at intermediate impact energies

    Energy Technology Data Exchange (ETDEWEB)

    Do, T. P. T. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); School of Education, Can Tho University, Campus II, 3/2 Street, Xuan Khanh, Ninh Kieu, Can Tho City (Viet Nam); Duque, H. V. [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Lopes, M. C. A. [Departamento de Física, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, Minas Gerais (Brazil); Konovalov, D. A.; White, R. D. [College of Science, Technology and Engineering, James Cook University, Townsville (Australia); Brunger, M. J., E-mail: michael.brunger@flinders.edu.au, E-mail: darryl.jones@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Jones, D. B., E-mail: michael.brunger@flinders.edu.au, E-mail: darryl.jones@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide, South Australia 5001 (Australia)

    2015-03-28

    We report differential cross sections (DCSs) for electron-impact vibrational-excitation of tetrahydrofuran, at intermediate incident electron energies (15-50 eV) and over the 10°-90° scattered electron angular range. These measurements extend the available DCS data for vibrational excitation for this species, which have previously been obtained at lower incident electron energies (≤20 eV). Where possible, our data are compared to the earlier measurements in the overlapping energy ranges. Here, quite good agreement was generally observed where the measurements overlapped.

  3. Program TOTELA calculating basic cross sections in intermediate energy region by using systematics

    International Nuclear Information System (INIS)

    Fukahori, Tokio; Niita, Koji

    2000-01-01

    Program TOTELA can calculate neutron- and proton-induced total, elastic scattering and reaction cross sections and angular distribution of elastic scattering in the intermediate energy region from 20 MeV to 3 GeV. The TOTELA adopts the systematics modified from that by Pearlstein to reproduce the experimental data and LA150 evaluation better. The calculated results compared with experimental data and LA150 evaluation are shown in figures. The TOTELA results can reproduce those data almost well. The TOTELA was developed to fill the lack of experimental data of above quantities in the intermediate energy region and to use for production of JENDL High Energy File. In the case that there is no experimental data of above quantities, the optical model parameters can be fitted by using TOTELA results. From this point of view, it is also useful to compare the optical model calculation by using RIPL with TOTELA results, in order to verify the parameter quality. Input data of TOTELA is only atomic and mass numbers of incident particle and target nuclide and input/output file names. The output of TOTELA calculation is in ENDF-6 format used in the intermediate energy nuclear data files. It is easy to modify the main routine by users. Details are written in each subroutine and main routine

  4. High-energy intermediates in protein unfolding characterized by thiol labeling under nativelike conditions.

    Science.gov (United States)

    Malhotra, Pooja; Udgaonkar, Jayant B

    2014-06-10

    A protein unfolding reaction usually appears to be so dominated by a large free energy barrier that identifying and characterizing high-energy intermediates and, hence, dissecting the unfolding reaction into multiple structural transitions have proven to be a challenge. In particular, it has been difficult to identify any detected high-energy intermediate with the dry (DMG) and wet (WMG) molten globules that have been implicated in the unfolding reactions of at least some proteins. In this study, a native-state thiol labeling methodology was used to identify high-energy intermediates, as well as to delineate the barriers to the disruption of side chain packing interactions and to site-specific solvent exposure in different regions of the small protein, single-chain monellin (MNEI). Labeling studies of four single-cysteine-containing variants of MNEI have identified three high-energy intermediates, populated to very low extents under nativelike conditions. A significant dispersion in the opening rates of the cysteine side chains has allowed multiple steps, leading to the loss of side chain packing, to be resolved temporally. A detailed structural analysis of the positions of the four cysteine residue positions, which are buried to different depths within the protein, has suggested a direct correlation with the structure of a DMG, detected in previous studies. It is observed that side chain packing within the core of the protein is maintained, while that at the surface is disrupted, in the DMG. The core of the protein becomes solvent-exposed only in a WMG populated after the rate-limiting step of unfolding at high denaturant concentrations.

  5. Photoproduction of neutral pions off protons

    NARCIS (Netherlands)

    Crede, V.; Sparks, N.; Wilson, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, Chr; Gregor, R.; Gridnev, A.; Gutz, E.; Hillert, W.; Hoffmeister, P.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Suele, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch

    2011-01-01

    Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector in the reaction gamma p -> p pi(0) for photon energies between 0.85 and 2.50 GeV. The pi(0) mesons are observed in their dominant neutral decay mode: pi(0) -> gamma gamma. For the first time, the differential cross

  6. Pion-pair production by two photons

    International Nuclear Information System (INIS)

    Terazawa, Hidezumi.

    1994-07-01

    The cross section for pion-pair production by two photons is calculated approximately by using the low energy theorem previously derived from partially-conserved-axial-vector-current hypothesis and current algebra, and found to agree very well with the experimental data recently obtained by the Mark II, TPC/Two-Gamma and CLEO Collaborations. (author)

  7. Chiral pion dynamics for spherical nucleon bags

    International Nuclear Information System (INIS)

    Vento, V.; Rho, M.; Nyman, E.M.; Jun, J.H.; Brown, G.E.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

    1980-01-01

    A chirally symmetric quark-bag model for the nucleon is obtained by introducing an explicit, classical, pion field exterior to the bag. The coupling at the bag surface is determined by the requirement of a conserved axial-vector current. The pion field satisfies equations of motion corresponding to the non-linear sigma-model. We study on this paper the simplified case where the bag and the pion field are spherically symmetric. Corrections due to gluon exchange between the quarks are ignored along with other interactions which split the N- and Δ-masses. The equations of motion for the pion field are solved and we find a substantial pion pressure at the bag surface, along with an attractive contribution to the nucleon self-energy. The total energy of the system, bag plus meson cloud, turns out to be approximately Msub(n)c 2 for a wide range of bag radii, from 1.5 fm down to about 0.5 fm. Introduction of a form factor for the pion would extend the range of possible radii to even smaller values. We propose that the bag with the smallest allowed radius be identified with the 'little bag' discussed before. One surprising result of the paper is that as long as one restricts to spherically symmetric bags, restoring chiral symmetry to the bag model makes the axial-vector current coupling constant gsub(A) to be always too large compared with the experimental value for any bag radius, suggesting a deviation from spherical symmetry for the intrinsic bag wave functions of the 'ground-state' hadrons. (orig.)

  8. Attained energy densities and neutral pion spectra in nucleus-nucleus collisions at 200 GeV/nucleon

    International Nuclear Information System (INIS)

    Plasil, F.; Albrecht, R.; Awes, T.C.

    1989-01-01

    The main goal of the CERN heavy-ion experiments is the search for an indication that the predicted state of deconfined quarks and gluons, the quark-gluon plasma (QGP), has been produced. The quantity most crucial to the probability of QGP formation is the thermalized energy density attained during the heavy-ion reaction. The amount of energy radiated transverse to the beam direction is the experimental quantity which is believed to be a measure of the amount of energy deposition in the reaction, and hence to reflect the energy density attained. In this presentation we consider the systematics of transverse energy production at CERN SPS energies, and we use the results to make estimates, under various assumptions, of attained energy densities. 18 refs., 2 figs

  9. Quantum signature in heavy-ion pion production

    International Nuclear Information System (INIS)

    Buvel, R.L.

    1985-01-01

    A revised model for pion production in heavy-ion peripheral collisions is presented. The pion-production mechanism investigated here is a two step process involving the formation and subsequent decay of an isobar resonance in the projectile nucleus. The independent-particle shell model with harmonic oscillator states is used to approximate the internal structure of the nucleus. The inclusion of the internal structure of the projectile nucleus led to the discovery of a quantum signature in the pion-production differential cross section. The quantum signature involves a matching condition where the pion-production differential cross section goes to zero for a particular value of the pion kinetic energy. The theory is compared to a recent experiment, but the results of this comparison are inconclusive

  10. Invariant potential for elastic pion--nucleus scattering

    International Nuclear Information System (INIS)

    Cammarata, J.B.; Banerjee, M.K.

    1976-01-01

    From the Wick-Dyson expansion of the exact propagator of a pion in the presence of a nucleus, an invariant potential for crossing symmetric elastic pion-nucleus scattering is obtained in terms of a series of pion-nucleon diagrams. The Chew-Low theory is used to develop a model in which the most important class of diagrams is effectively summed. Included in this model is the exclusion principle restriction on the pion-bound nucleon interaction, the effects of the binding of nucleons, a kinematic transformation of energy from the lab to the πN center of mass frame, and the Fermi motion and recoil of the target nucleons. From a numerical study of the effects of these processes on the π- 12 C total cross section, the relative importance of each is determined. Other processes contributing to the elastic scattering of pions not included in the present model are also discussed

  11. Selected problems in experimental intermediate energy physics. Final technical report, February 1, 1991--January 31, 1994

    International Nuclear Information System (INIS)

    Mayes, B.W.; Hungerford, E.V.; Pinsky, L.S.

    1997-01-01

    A complete description of the research program of the intermediate energy group at the University of Houston may be found in previous progress reports, renewal proposals, and proposals to various accelerator advisory committees. The summaries of activities are presented in the next section. The objectives of the research program are to: (1) investigate selected, forefront problems in experimental intermediate energy physics; (2) educate students in this field of research; and (3) develop the instrumentation necessary to undertake this experimental program. There were three major thrusts of the program: (1) strange particle physics, where a strange quark is embedded in the nuclear medium; (2) muon electro-weak decay, which involves a search for a violation of the standard model of the electro-weak interaction; and (3) measurement of the spin dependent structure function of the neutron and proton

  12. Intermediate-energy nuclear physics. Task C. Technical progress report, October 1, 1982-October 1, 1983. Part I

    International Nuclear Information System (INIS)

    1983-01-01

    Progress is reported on the following experimental studies: (1) excitation of giant resonances in 118 Sn in inelastic pion scattering at 130 MeV; (2) giant dipole excitations of 40 Ca by inelastic pion scattering; (3) charge symmetry test using the π + and π - elastic scattering from deuterium at 143 and 256 MeV; (4) binding energy effects on the isospin amplitudes in p-shell nuclei; (5) the energy dependence of the 14 C (π + ,π 0 ) 14 N reaction to the IAS; (6) the ( 3 He,t) reaction at 2 GeV; (7) analyzing power in the (polarized p,n) IAS transitions; (8) the excitation of the 1/2 + (2.36) MeV state in the 24Mg (polarized p,d) reaction from 27 to 150 MeV; (9) the energy dependence of the (polarized p,d) reaction for 54 Fe and 140 Ce; and (10) the energy dependence of the 7 Li(p,d) 6 Li reaction. Publications are listed

  13. (Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions)

    Energy Technology Data Exchange (ETDEWEB)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy (< 10 MeV/A), intermediate energy (10--100 MeV/A) and relativistic (> 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon {sup 129}Xe with {sup 197}Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon {sup 12}C with {sup 197}Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated.

  14. Supplement to the report of the Expert Committee 'Intermediate-Energy Physics' 1986-1988/89

    International Nuclear Information System (INIS)

    1990-02-01

    In the supplement to the scientitic report of the sponsoring project of the Federal Ministery for Research and Technology 'Intermediate-Energy Physics' the publications are collected, which have come out in the three years of the sponsoring in the single projects. Essentially only journal articles were taken up, in order to keep the extent of this list surveyable. On the taking up of the manifold of dissertations, diploma theses, and talks generally was abandoned. (orig.) [de

  15. An in-beam test study of the response of calorimeters in the ATLAS Experiment of LHC to charged pions of 3 to 350 GeV energy range

    International Nuclear Information System (INIS)

    Giangiobbe Vincent

    2006-11-01

    ATLAS is one of the four main experiments under way of installing within the Large Hadron Project (LHC). LHC will provide two proton beams of high luminosity (1 x 10 34 cm -2 s -1 at peak), colliding in the center of ATLAS detector at a 14 TeV rated COM energy. The aim of this study is an in-beam test characterization of the response of calorimeters in the central part of ATLAS. The study will be focused on the response to pions as main jet components. In the beginning a short presentation of the ATLAS program of physics is given enlightening the basic theoretical and experimental aspects of the experiment. A description of the ATLAS detector is also presented. The second chapter is devoted to detailed description of the central calorimetry of ATLAS. One starts from the mechanism of signal production in calorimeters, through the electronic processing up to the reconstruction of the released energy. The third chapter deals with the processing electronics of the TileCal hadron calorimeter the installation and certification at CERN of which was in charge of Clermont-Ferrand team. The chapter 4 gives a description of the SPS beam line and of the associated instrumentation tested in-beam in 2004. The chapters 6 and 7 are devoted to the study of the response of calorimeters to high energy pions (within 20 to 350 GeV range). The pion selection is described in the chapter 5. In the eighth chapter the calorimeter response to low energy pions (up to 9 GeV) is examined. In conclusion this study has shown that the data concerning pions obtained in-beam in 2004 are usable for energies within 3 to 350 GeV. The response and the energy resolution of LAr and TileCal were measured with a satisfactory accuracy,. A systematic comparison of these results with simulations (in the configuration of in-beam test) can now be done. Should the agreement be satisfying, the modelling could be used for the study of calibration of calorimeter response for the case of works with the jets

  16. Near-threshold charged pion photoproduction from 13C

    International Nuclear Information System (INIS)

    LeRose, J.J.

    1981-01-01

    Differential cross sections to discrete final states have been measured for both positive and negative pion photo-production on 13 C at 90 0 in the lab at pion energies of 18, 29, and 41 MeV. Measurements were made using a fixed angle magnetic spectrometer located in the 14 0 area of the MIT Bates linear accelerator. Pions were detected using a 90 channel multi-wire proportional counter in the focal plane along with a backup array consisting of three 1/16'' thick plastic scintillator detectors and a 1/2'' thick Cerenkov detector. Positive pion photo-production cross sections were obtained for the excitation of the 3/2 - ground state and for the 3.45 MeV first excited state of 13 B. Negative pion photo-production cross sections were obtained for the excitation of the 1/2 - ground state, and the 3/2 to 3.51 MeV and 5/2 to 7.39 MeV excited states of 13 N. The measured positive pion photo-production ground state cross sections are in reasonable agreement wth theoretical calculations. However, there is a large discrepancy between the measured negative pion photoproduction ground state cross sections and the theoretical values. There are no theoretical calculations available for comparison with the excited state measurements in either positive or negative pion photoproduction on 13 C

  17. Development of an intermediate energy heavy-ion micro-beam irradiation system

    International Nuclear Information System (INIS)

    Song Mingtao; Wang Zhiguang; He Yuan; Gao Daqing; Yang Xiaotian; Liu Jie; Su Hong; Man Kaidi; Sheng Li'na

    2008-01-01

    The micro-beam irradiation system, which focuses the beam down the micron order and precisely delivers a predefined number of ions to a predefined spot of micron order, is a powerful tool for radio-biology, radio-biomedicine and micromachining. The Institute of Modern Physics of Chinese Academy of Sciences is developing a heavy-ion micro-beam irradiation system up to intermediate energy. Based on the intermediate and low energy beam provided by Heavy Ion Research Facility of Lanzhou, the micro-beam system takes the form of the magnetic focusing. The heavy-ion beam is conducted to the basement by a symmetrical achromatic system consisting of two vertical bending magnets and a quadrupole in between. Then a beam spot of micron order is formed by magnetic triplet quadrupole of very high gradient. The sample can be irradiated either in vacuum or in the air. This system will be the first opening platform capable of providing heavy ion micro-beam, ranging from low (10 MeV/u) to intermediate energy (100 MeV/u), for irradiation experiment with positioning and counting accuracy. Target material may be biology cell, tissue or other non-biological materials. It will be a help for unveiling the essence of heavy-ion interaction with matter and also a new means for exploring the application of heavy-ion irradiation. (authors)

  18. High energy physics and nuclear structure

    International Nuclear Information System (INIS)

    Measday, D.F.; Thomas, A.W.

    1980-01-01

    These proceedings contain the papers presented at the named conference. These concern eletromagnetic interactions, weak interactions, strong interactions at intermediate energy, pion reactions, proton reactions, strong interactions at high energy, as well as new facilities and applications. See hints under the relevant topics. (HSI)

  19. Proton multiplicity distributions in pion-xenon nucleus collisions at 3.5 GeV/c

    International Nuclear Information System (INIS)

    Strugalski, Z.; Pawlak, T.; Peryt, W.; Pluta, J.

    1980-01-01

    Experimental results from the proton emission investigation in 3.5 GeV/c pion minus-xenon nucleus collisions detected in the 180 xenon bubble chamber are presented and analyzed. The emitted protons are of kinetic energies from 20 to 400 MeV. Multiplicity distributions of protons both accompanied and not accompanied by secondary charged and neutral pions are given. Large proton multiplicities are observed in the events without multiparticle production, the proton multiplicity distribution in this class of events being of an irregular character. The experimental results are well described in the model based on the following hypothesis: a high energy hadron traversing the target causes the monotonous emission of the fast protons in numbers nsub(p) being equal to the number of protons encountered in the neighbourhood of its path inside the nucleus target. In this case the multiple production goes through some intermediate states which decay after having left the target nucleus

  20. Coherent pion production induced by protons and light ions

    International Nuclear Information System (INIS)

    Fernandez de Cordoba, P.; Oset, E.; Vicente-Vacas, M.J.

    1995-01-01

    We study coherent pion production by means of the (p,n) and (He,t) reactions on different nuclei and at different energies of the projectile. Energy and angular distributions are calculated. The angular distributions are rather narrow along the direction of the momentum transfer, particularly in heavy nuclei. The reaction is sensitive to the longitudinal part of the elementary NN→NΔ interaction. It also provides a new tool to obtain information on the pion-nuclear interaction, complementary to that offered by reactions with real pions. (orig.)

  1. Reactor-moderated intermediate-energy neutron beams for neutron-capture therapy

    International Nuclear Information System (INIS)

    Less, T.J.

    1987-01-01

    One approach to producing an intermediate energy beam is moderating fission neutrons escaping from a reactor core. The objective of this research is to evaluate materials that might produce an intermediate beam for NCT via moderation of fission neutrons. A second objective is to use the more promising moderator material in a preliminary design of an NCT facility at a research reactor. The evaluations showed that several materials or combinations of materials could produce a moderator source for an intermediate beam for NCT. The best neutron spectrum for use in NCT is produced by Al 2 O 3 , but mixtures of Al metal and D 2 O are also attractive. Using the best moderator materials, results were applied to the design of an NCT moderator at the Georgia Institute of Technology Research Reactor's bio-medical facility. The amount of photon shielding and thermal neutron absorber were optimized with respect to the desired photon dose rate and intermediate neutron flux at the patient position

  2. A possible method to produce a polarized antiproton beam at intermediate energies

    International Nuclear Information System (INIS)

    Spinka, H.; Vaandering, E.W.; Hofmann, J.S.

    1994-01-01

    A feasible and conservative design for a medium energy polarized antiproton beam has been presented. The design requires an intense beam of unpolarized antiprotons (≥ 10 7 /sec) from a typical secondary beam line in order to achieve reasonable anti pp elastic scattering count rates. All three beam spin directions can be achieved. Methods were discussed to reverse the spin directions in modest times, and to change to a polarized proton beam if desired. It is expected that experiments with such a beam would have a profound effect on the understanding of the anti NN interaction at intermediate energies

  3. Isovector couplings for nucleon charge-exchange reactions at intermediate energies

    International Nuclear Information System (INIS)

    Love, W.G.; Nakayama, K.; Franey, M.A.

    1987-01-01

    The isovector parts of the effective nucleon-nucleon interaction are studied by examination of the reaction /sup 14/C(p,n) at intermediate energies near zero momentum transfer with use of recently developed G-matrix and free--t-matrix interactions. The spin-independent coupling (V/sub tau/) exhibits a strong energy and density dependence which, in the case of the G matrix based on the Bonn potential, significantly improves the agreement between calculated values of chemical bondV/sub σ//sub tau//V/sub tau/chemical bond 2 at q = 0 and those recently extracted from the reaction /sup 14/C

  4. Unified description of neutron-, proton- and photon-induced fission cross sections in intermediate energy region

    International Nuclear Information System (INIS)

    Fukahori, Tokio; Iwamoto, Osamu; Chiba, Satoshi

    2003-01-01

    For an accelerator-driven nuclear waste transmutation system, it is very important to estimate sub-criticality of core system for feasibility and design study of the system. The fission cross section in the intermediate energy range has an important role. A program FISCAL has been developed to calculate neutron-, proton- and photon-induced fission cross sections in the energy region from several tens of MeV to 3 GeV. FISCAL adopts the systematics considering experimental data for Ag- 243 Am. It is found that unified description of neutron-, proton- and photon-induced fission cross sections is available. (author)

  5. DWBA differential and total pair production cross sections for intermediate energy photons

    International Nuclear Information System (INIS)

    Selvaraju, C.; Bhullar, A.S.; Sud, K.K.

    2001-01-01

    We present in this communication the theoretical differential and total cross section for electron-positron pair creation by intermediate energy photons (5.0-10.0 MeV) on different targets (Z=1, 30, 50, 68, 82 and 92). The computed cross sections are in distorted wave Born approximation (DWBA) in point Coulomb potential. The database of the differential and total pair production cross sections is presented in tabulated as well as in graphical form and the interpolation of differential cross sections for different atomic numbers, positron and photon energies is discussed

  6. Simulation of neutron rich nuclei production through 239U fission at intermediates energies

    International Nuclear Information System (INIS)

    Mirea, M.; Clapier, F.; Pauwels, N.; Proust, J.

    1997-01-01

    The theoretical part and some results obtained from a model realised for fission processes in wide range of mass-asymmetries are presented. The fission barriers are computed in a tridimensional configuration space using the Yukawa - plus - exponential macroscopic energies corrected within the Strutinsky procedure. It is assumed that channel probabilities are proportional with Gamow penetrabilities. The model is applied for the disintegration of the 239 U in order to determine the relative yields for the production of neutron rich nuclei at diverse intermediate energies. (author)

  7. The origin of nuclear spin and its effect durning intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Zhang Guoqiang; Cao Xiguang; Fu Yao; Ma Yugang; Cai Xiangzhou; Wang Hongwei; Fang Deqing; Tian Wendong; Chen Jingen; Guo Wei; Liu Guihua

    2010-01-01

    We use the heavy-ion phase-space exploration (HIPSE) model to discuss the origin of the nuclear spin and its effect in Intermediate energy nuclear reaction. It is found that the spin of projectile depends on the impact parameter of the reaction system heavily, while on the violence lightly by contrast. Some interesting multifragmentation phenomena related to the spin are shown, especially those of phase transition. At the same time, the role of excited energy for multifragmentation is also invested. We find the later plays a more robust role durning the nuclear disintegration. (authors)

  8. Origin of the finite nuclear spin and its effect in intermediate energy heavy ion collisions

    International Nuclear Information System (INIS)

    Zhang Guoqiang; Cao Xiguang; Fu Yao

    2012-01-01

    The heavy-ion phase-space exploration (HIPSE) model is used to discuss the origin of the nuclear spin in intermediate energy heavy-ion collision (HIC). The spin of maximal projectile-like fragment is found to depend strongly on impact parameter of a reaction system,while it relates weakly to the collision violence. Some interesting multi-fragmentation phenomena related to the spin are shown. We also found that the excitation energy in the de-excitation stage plays a robust role at the de-excitation stage in HIC. (authors)

  9. The 2-ID-B intermediate-energy scanning X-ray microscope at the APS

    International Nuclear Information System (INIS)

    McNulty, I.; Paterson, D.; Arko, J.; Erdmann, M.; Goetze, K.; Ilinski, P.; Mooney, T.; Vogt, S.; Xu, S.; Frigo, S.P.; Stampfl, A.P.J.; Wang, Y.

    2002-01-01

    The intermediate-energy scanning x-ray microscope at beamline 2-ID-B at the Advanced Photon Source is a dedicated instrument for materials and biological research. The microscope uses a zone plate lens to focus coherent 1-4 keV x-rays to a 60 nm focal spot of 10 9 photons/s onto the sample. It records simultaneous transmission and energy-resolved fluorescence images. We have used the microscope for nano-tomography of chips and micro-spectroscopy of cells. (authors)

  10. Inclusive production of ρ0 mesons on protons with photons, pion and kaon beams in the energy range from 65 to 175 GeV

    International Nuclear Information System (INIS)

    Hofmann, R.P.

    1991-03-01

    Cross sections of the inclusive photoproduction and hadroproduction of the ρ 0 (770) meson on a liquid hydrogen target are given as functions of p perpendicular to (varying from 0 to 2 GeV) and x F (-0.1 to 1.0) where the photon energy range is 65 to 175 GeV and the hadrons are charged π and K of the energies 80 and 140 GeV. The ρ-signal is quantified in fits to the π + π - -mass distributions accounting for a downward mass shift of the ρ 0 peak known from the diffractive ρ 0 -production. This mass shift is shown to be significantly different from zero also in the low-x F -low-p perpendicular to region in both photon and hadron data. The ratios d 2 σ/dp perpendicular to dx F (γp→ρ 0 X)/d 2 σ/dp perpendicular to dx F (π/Kp→ρ 0 X) give an x F - and π perpendicular to - dependent VMD-factor. Comparison of hadron and photon cross sections shows a difference due to the pointlike photon-hadron-coupling at large p perpendicular to . This onset is in good quantitative agreement with the predictions of the LUCIFER-Monte-Carlo. The low and medium x F -range can be described by a quark-antiquark-fusion-model. The high x F -regions show distinct decay angular distributions matching the predictions for diffractive photoproduction and the one-pion-exchange model respectively. (orig.) [de

  11. Proceedings of the LAMPF workshop on pion double charge exchange

    International Nuclear Information System (INIS)

    Baer, H.W.; Leitch, M.J.

    1985-09-01

    Experimental and theoretical aspects of double-analog, nonanalog, and continuum pion double charge exchange in the 50- to 310-MeV energy range are covered. Separate abstracts were prepared for 22 papers in these proceedings

  12. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density

    Science.gov (United States)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-02-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium-nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg-1, higher than that of conventional tubular sodium-nickel chloride batteries (280 °C), is obtained for planar sodium-nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium-nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.

  13. Reconstruction of the electron energy distribution function from probe characteristics at intermediate and high pressures

    International Nuclear Information System (INIS)

    Arslanbekov, R.R.; Kolokolov, N.B.; Kudryavtsev, A.A.; Khromov, N.A.

    1991-01-01

    Gorbunov et al. have developed a kinetic theory of the electron current drawn by a probe, which substantially extends the region of applicability of the probe method for determining the electron energy distribution function, enabling probes to be used for intermediate and high pressures (up to p ≤ 0.5 atm for monatomic gases). They showed that for λ var-epsilon >> a + d (where a is the probe radius, d is the sheath thickness, and λ var-epsilon is the electron energy relaxation length) the current density j e (V) drawn by the probe is related to the unperturbed distribution function by an integral equation involving the distribution function. The kernal of the integral equation can be written as a function of the diffusion parameter. In the present paper the method of quadrature sums is employed in order to obtain the electron energy distribution function from probe characteristics at intermediate and high pressures. This technique enables them to recover the distribution function from the integral equation when the diffusion parameter has an arbitrary energy dependence ψ 0 (var-epsilon) in any given energy range. The effectiveness of the method is demonstrated by application to both model problems and experimental data

  14. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

    International Nuclear Information System (INIS)

    Tso, Kin.

    1996-05-01

    The 129 Xe-induced reactions on nat Cu, 89 Y, 165 Ho, and 197 Au at bombarding energies of E/A = 40 ampersand 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129 Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied

  15. Multifragmentation in intermediate energy 129Xe-induced heavy-ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Tso, Kin [Univ. of California, Berkeley, CA (United States)

    1996-05-01

    The 129Xe-induced reactions on natCu, 89Y, 165Ho, and 197Au at bombarding energies of E/A = 40 & 60 MeV have been studied theoretically and experimentally in order to establish the underlying mechanism of multifragmentation at intermediate energy heavy-Ion collisions. Nuclear disks formed in central heavy-ion collisions, as simulated by means of Boltzmann-like kinetic equations, break up into several fragments due to a new kind of Rayleigh-like surface instability. A sheet of liquid, stable in the limit of non-interacting surfaces, is shown to become unstable due to surface-surface interactions. The onset of this instability is determined analytically. A thin bubble behaves like a sheet and is susceptible to the surface instability through the crispation mode. The Coulomb effects associated with the depletion of charges in the central cavity of nuclear bubbles are investigated. The onset of Coulomb instability is demonstrated for perturbations of the radial mode. Experimental intermediate-mass-fragment multiplicity distributions for the 129Xe-induced reactions are shown to be binomial at each transverse energy. From these distributions, independent of the specific target, an elementary binary decay probability p can be extracted that has a thermal dependence. Thus it is inferred that multifragmentation is reducible to a combination of nearly independent emission processes. If sequential decay is assumed, the increase of p with transverse energy implies a contraction of the emission time scale. The sensitivity of p to the lower Z threshold in the definition of intermediate-mass-fragments points to a physical Poisson simulations of the particle multiplicities show that the weak auto-correlation between the fragment multiplicity and the transverse energy does not distort a Poisson distribution into a binomial distribution. The effect of device efficiency on the experimental results has also been studied.

  16. Study of leading neutral pions: (interactions of cosmic rays with matter at energies above 3 TeV)

    International Nuclear Information System (INIS)

    Eremenko, Yu.A.

    1988-01-01

    An experimental plant consisting of a full-automatic ionized colorimeter of 44m 2 , electronics of which is based on modern integral schemes and performed in CAMAC standard; of an x-ray emulsion chamber and of changeable dense target is described. The plant permits to measure the energy of a primary particle, as well as to study in detail a neutral component of products of strong indifferent target atoms. Experimental data on leading neutral mesons with energy from 10 GeV to the cosmic particle energies are analysed using the plant. A new experiment, which aim is the detection of interactions with anomalously great multiplicity and study of microstructure of extensive air showers, is suggested. 277 refs

  17. Measurement of the Charged-Pion Polarizability

    CERN Document Server

    Adolph, C.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dinkelbach, A.M.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Guthorl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Hoppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kroumchtein, Z.V.; Kuchinski, N.; Kuhn, R.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Moinester, M.A.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peshekhonov, D.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Rocco, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Virius, M.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

    2015-02-10

    The COMPASS collaboration at CERN has investigated pion Compton scattering, $\\pi^-\\gamma\\rightarrow \\pi^-\\gamma$, at centre-of-mass energy below 3.5 pion masses. The process is embedded in the reaction $\\pi^-\\mathrm{Ni}\\rightarrow\\pi^-\\gamma\\;\\mathrm{Ni}$, which is initiated by 190 GeV pions impinging on a nickel target. The exchange of quasi-real photons is selected by isolating the sharp Coulomb peak observed at smallest momentum transfers, $Q^2<0.0015$ (GeV/$c$)$^2$. From a sample of 63 000 events the pion electric polarisability is determined to be $\\alpha_\\pi = (2.0 \\pm 0.6_{\\mbox{stat}} \\pm 0.7_{\\mbox{syst}}) \\times 10^{-4} \\mbox{fm}^3$ under the assumption $\\alpha_\\pi=-\\beta_\\pi$, which relates the electric and magnetic dipole polarisabilities. It is the most precise measurement of this fundamental low-energy parameter of strong interaction, that has been addressed since long by various methods with conflicting outcomes. While this result is in tension with previous dedicated measurements, it is fou...

  18. Investigation of pion-nucleus interactions

    International Nuclear Information System (INIS)

    Moore, C.F.

    1992-09-01

    This report summarizes the work carried out by personnel from the University of Texas at Austin at the Los Alamos Clinton P. Anderson Meson Physics Facility (LAMPF). The research activities involved experiments done with the Energetic Pion Channel and Spectrometer (EPICS), the Low Energy Pion Channel (LEP), the Pion and Particle Physics Channel (P 3 ), the High Resolution Spectrometer (HRS), and planning a new experimental program associated with the new high-resolution Neutral Meson Spectrometer (NMS) at LAMPF. A brief overview of work supported by this grant is given followed by an account of the study of the double giant resonances in pion double charge exchange on 51 V, 115 In, and 197 Au. This report contains a list of published papers and preprints, abstracts, and invited talks. These papers summarize experiments involving participants supported by this grant and indicate the work accomplished by these participants in this program of medium energy nuclear physics research. Lists of the most recent proposals on which we have participation at LAMPF, proposals which have been approved this past year to run as experiments, personnel who have participated in this research program are included. The research cited in this report is, in many cases, the collaborative effort of many groups associated with research at LAMPF

  19. Polarized proton induced pion production on 10B at 200, 225, 250 and 260 MeV incident energies

    International Nuclear Information System (INIS)

    Ziegler, W.; Auld, E.G.; Falk, W.R.; Giles, G.L.; Jones, G.; Lolos, G.J.; McParland, B.

    1985-02-01

    The angular distributions of both the differential cross-section and the analyzing power are presented for the 10 B(p,π) 11 B reaction leading to the ground and first excited states of 11 B. The differential cross-section shows very little angular structure or energy dependence, but the analyzing power exhibits a considerable energy dependence for both states. This dependence, similar to that observed for the 12 C(p,π + ) 13 C reaction, may be a signature of the fact that single-particle final states are involved

  20. Faddeev and Glauber calculations at intermediate energies in a model for n+d scattering

    International Nuclear Information System (INIS)

    Elster, Ch.; Lin, T.; Gloeckle, W.; Jeschonnek, S.

    2008-01-01

    Obtaining cross sections for nuclear reactions at intermediate energies based on the Glauber formulation has a long tradition. Only recently the energy regime of a few hundred MeV has become accessible to ab initio Faddeev calculations of three-body scattering. In order to go to higher energies, the Faddeev equation for three-body scattering is formulated and directly solved without employing a partial wave decomposition. In the simplest form the Faddeev equation for interacting scalar particles is a three-dimensional integral equation in five variables, from which the total cross section, the cross sections for elastic scattering and breakup reactions, as well as differential cross sections are obtained. The same observables are calculated based on the Glauber formulation. The first order Glauber calculation and the Glauber rescattering corrections are compared in detail with the corresponding terms of the Faddeev multiple scattering series for projectile energies between 100 MeV and 2 GeV

  1. Spin observables at intermediate energies: a tool in viewing the nucleus

    International Nuclear Information System (INIS)

    McClelland, J.B.

    1986-01-01

    This paper attempts to summarize some of the advances made in intermediate nuclear physics through measurements of spin observables, notably in the range of bombarding energies from 100 to 1000 MeV. Relative to measurements of cross section, spin observables offer a highly selective filter in viewing the nucleus. Their general utility is found in their sensitivity to particular nuclear transitions and is further augmented by their simple connections to the NN force. The advantage of higher energies is apparent from the dominance of single-step mechanisms even at large energy losses where general nuclear spin responses may be made. Experimentally, this is an energy range where efficient, high-analyzing-power polarimeters can be coupled with high resolution detection techniques. 29 refs., 5 figs

  2. Characteristics of intermediate-energy nucleons emitted from 50 GeV

    International Nuclear Information System (INIS)

    Goyal, D.P.; Singh, S.; Arya, N.S.

    1984-01-01

    The multiplicity and angular distributions of intermediate-energy (grey) nucleons are studied from 50 GeV π - -nucleus data and compared with those available from π - -nucleus and p-nucleus interactions at other energies. The value of is found to be dependent both on the energy as well as on the projectile. The former variation is attributable to kinematics and the latter explainable on the basis of the additive quark model. The angular distribution of grey particles is found to be independent of energy, projectile and target, which supports the view that grey particles are chiefly due to knock-on recoiling protons. The various versions of the cascade model, however, are unable to explain any of the observed features of grey-particle distributions

  3. OPEM3-program for calculating pion differential spectra in pp → npπ+ reaction at energies up to 1 GeV. Physical model

    International Nuclear Information System (INIS)

    Suslenko, V.K.; Gajsak, I.I.

    1982-01-01

    Theoretical basis for the program to calcUlate the denSjties of differential criss sections of the third order (spectra) for pions produced in the reaction pp → npπ + at enerajes up to 1 GeV is presented. A variant of one pion exchange model (OPEM), im which precise account of all contributions from four polar Feynman diagrams is made is selected as a a physical model of the reaction pp → npπ + . The model apparatus is presented in correspondence with the scheme of the structure of OPEM 3 program for computer realized in Fortran language

  4. Partial inelasticity coefficients of negative pions in p, d, α, 12C + 12C and p, 12C + 181Ta collisions at 4.2 GeV/c per nucleon

    International Nuclear Information System (INIS)

    Olimov, K.K.; Olimov, K.; Gulamov, K.G.; Olimov, A.K.; Lutpullaev, S.L.; Yuldashev, B.S.; Haseeb, M.Q.

    2015-01-01

    The partial inelasticity coefficients of the negative pions were determined in minimum bias p, d, α, 12 C + 12 C and p, 12 C + 18 Ta collisions at 4.2A GeV/c taking into account the average number of participant nucleons of a projectile nucleus. In nucleus–nucleus collisions, the average values of partial inelasticity coefficients (〈K(π-)〉) of the negative pions did not depend on the mass numbers of projectile and target nuclei. Increase of 〈K(π - )〉 in going from p + 12 C to d, α, 12 C + 12 C collisions was due to an additional source of production of fast negative pions in nucleus–nucleus collisions — a charge exchange conversion of one or more neutrons of a projectile nucleus into a proton and π - . Linking the experimental results of the present analysis at intermediate energy with those obtained at high and ultra-high energies, it was concluded that the average values of partial inelasticity coefficients of pions in nucleon–nucleus and nucleus–nucleus collisions manifest a transitive behavior. At intermediate energies, the values of 〈K(π - )〉 were smaller by a factor of two and more as compared to those at high energies, and they increased further with increasing incident energy, reaching a plateau at E 0 > 100A GeV. (author)

  5. The (3He,t) and (d,2He)reactions at intermediate energies

    International Nuclear Information System (INIS)

    Brockstedt, A.

    1987-09-01

    The ( 3 He,t) reaction has been studied at 0.6-2.3 GeV at small scattering angles, 0-7 degrees, on various nuclei ( 12 C, 13 C, 26 Mg, 40 Ca, 48 Ca, 54 Fe, 90 Zr, 159 Tb, 208 Pb) including a proton target. The reaction is a single-step reaction and selects the spin-isospin channel. Angular distributions for low-lying states in 12 N are well described by DWIA calculations. From 13 C to 13 N transitions the ratio J στ /J τ , at momentum transfer, q, close to zero, is derived. The ratio remains roughly constant in the region 300 - 700 MeV/nucleon. The position of the quasi-free peak is shifted compared with free nucleon-nucleon scattering. The shift is towards higher excitation energies at q approx 1.4 fm -1 , and towards lower excitation energies at q approx 2.5 fm -1 . The p( 3 He,t)Δ ++ reaction is analysed as one-pion exchange and the ( 3 He,t) form factor is extracted. The shape and position of the Δ resonance seem to be independent of target mass for the targets studied. Compared with the p to Δ ++ transition the position is shifted towards lower excitation energy in nuclei. The (d,2p[ 1 S 0 ]) reaction, with the two protons in an 1 S 0 state labelled 2 He, is studied at 0.65 and 2.0 GeV at small angles, 0-4 degrees, on some of the targets used in the ( 3 He,t) experiment (p, 12 C, 40 Ca, 54 Fe). This reaction is also a one-step reaction that can be used for studies of spin-isospin excitations. Cross sections and tensor analysing powers are determined for the p(d, 2 He)n reaction. These results are compared with PWIA calculations. The Δ resonance in carbon is also here shifted down in excitation energy compared with the proton target. (author)

  6. Roy-Steiner-equation analysis of pion-nucleon scattering

    Science.gov (United States)

    Meißner, U.-G.; Ruiz de Elvira, J.; Hoferichter, M.; Kubis, B.

    2017-03-01

    Low-energy pion-nucleon scattering is relevant for many areas in nuclear and hadronic physics, ranging from the scalar couplings of the nucleon to the long-range part of two-pion-exchange potentials and three-nucleon forces in Chiral Effective Field Theory. In this talk, we show how the fruitful combination of dispersion-theoretical methods, in particular in the form of Roy-Steiner equations, with modern high-precision data on hadronic atoms allows one to determine the pion-nucleon scattering amplitudes at low energies with unprecedented accuracy. Special attention will be paid to the extraction of the pion-nucleon σ-term, and we discuss in detail the current tension with recent lattice results, as well as the determination of the low-energy constants of chiral perturbation theory.

  7. Can one distinguish τ-neutrinos from antineutrinos in neutral-current pion production processes?

    International Nuclear Information System (INIS)

    Hernandez, E.; Nieves, J.; Valverde, M.

    2007-01-01

    A potential way to distinguish τ-neutrinos from antineutrinos, below the τ-production threshold, but above the pion production one, is presented. It is based on the different behavior of the neutral-current pion production off the nucleon, depending on whether it is induced by neutrinos or antineutrinos. This procedure for distinguishing τ-neutrinos from antineutrinos neither relies on any nuclear model, nor it is affected by any nuclear effect (distortion of the outgoing nucleon waves, etc.). We show that neutrino-antineutrino asymmetries occur both in the totally integrated cross sections and in the pion azimuthal differential distributions. To define the asymmetries for the latter distributions we just rely on Lorentz-invariance. All these asymmetries are independent of the lepton family and can be experimentally measured by using electron or muon neutrinos, due to the lepton family universality of the neutral-current neutrino interaction. Nevertheless and to estimate their size, we have also used the chiral model of [E. Hernandez, J. Nieves, M. Valverde, hep-ph/0701149] at intermediate energies. Results are really significant since the differences between neutrino and antineutrino induced reactions are always large in all physical channels

  8. Streamer chamber: pion decay

    CERN Multimedia

    1992-01-01

    The real particles produced in the decay of a positive pion can be seen in this image from a streamer chamber. Streamer chambers consist of a gas chamber through which a strong pulsed electric field is passed, creating sparks as a charged particle passes through it. A magnetic field is added to cause the decay products to follow curved paths so that their charge and momentum can be measured.

  9. Pion Rescattering in Nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Paschos, E.A. [Institute for Physics, University of Dortmund, 44221 Dortmund (Germany); Schienbein, I. [Deutsches Elektronen Synchroton (DESY), 22603 Hamburg (Germany); Yu, J.-Y. [Institute for Physics, University of Dortmund, 44221 Dortmund (Germany)

    2005-02-15

    Nuclear corrections are presented for neutrino and electron induced reactions in a pedagogical manner. The formalism is demonstrated with numerical studies and shown to produce substantial corrections in channels where the pions have the same charge with the exchanged current. Two comparisons with available data show consistency of the model. Additional experimental results along these lines will improve the accuracy of the predictions and enhance the discovery potential of experiments.

  10. Recent developments in the understanding of pion-nucleus scattering

    International Nuclear Information System (INIS)

    Johnson, M.B.

    1983-01-01

    A development of the theory of pion-nucleus scattering is given in a field theoretical framework. The theory is designed to describe pion elastic scattering and single- and double-charge exchange to isobaric analog states. An analysis of recent data at low and resonance energies is made. Strong modifications to the simple picture of the scattering as a succession of free pion-nucleon interactions are required in order to understand the data. The extent to which the experiment is understood in terms of microscopic theory is indicated. 71 references

  11. Universal pion freeze-out in heavy-ion collisions.

    Science.gov (United States)

    Adamová, D; Agakichiev, G; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanović, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Z; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B; Ludolphs, W; Maas, A; Marín, A; Milosević, J; Milov, A; Miśkowiec, D; Panebrattsev, Yu; Petchenova, O; Petrácek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schmitz, W; Schukraft, J; Sedykh, S; Shimansky, S; Slívová, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, I; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V

    2003-01-17

    Based on an evaluation of data on pion interferometry and on particle yields at midrapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda(f) reaches a value of about 1 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and beam energy from the Alternating Gradient Synchrotron to the Relativistic Heavy Ion Collider.

  12. Universal pion freeze-out in heavy-ion collisions

    CERN Document Server

    Adamova, D; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B C; Ludolphs, W; Maas, A; Marin, A; Milosevic, J; Milov, A; Miskowiec, D; Panebratsev, Yu A; Petchenova, O Yu; Petracek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schükraft, Jürgen; Sedykh, S; Shimansky, S S; Slivova, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V; Schmitz, W

    2003-01-01

    Based on an evaluation of recent systematic data on two-pion interferometry and on measured particle yields at mid-rapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda_f reaches a value of approximately 2.5 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and its value is constant at all currently available beam energies from AGS to RHIC.

  13. Photoproduction de Mesons sur le Nucleon aux Energies Intermediaire (in French) [Photoproduction of mesons on the nucleon at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, Michel [Univ. of Paris, Orsay (France)

    1996-12-13

    One object of this thesis is to propose a model taking account of low transfer reaction mechanisms for a series of photoproduction reactions on nucleons for photon energies ≳4 GeV. If our comprehension of processes with low transfers is correct, then extrapolating our model in the domain of large transfers and the comparison with data supplied will give us information on the domains in energy and transfers from which an interpretation of reactions in terms of the "soft" process ceases to be valid. In the domain of large transfers, only one approach in terms of "hard" process can then explain the data. We are interested in electromagnetic photoproduction reactions because the probe, firstly, interacts with the target via an exact and well known mechanism (described by the QED theory) and also eliminates the interaction phenomena in the initial state. No probe is as well known as the photon. The extraction of reaction mechanisms, amplitudes and coupling constants match is made easier than in the case of hadronic probes. The energy domain Eγ >4 GeV studied is particularly interesting because it is from this energy of incident photons that can be expected to achieve large enough pulse transfers to hope for emergence of hard processes and therefore see the cessation of validity of interpretation of hadron models. Also, resonance effects are minor and do not interfere with our interpretations. Experimentally, this area is widely unexplored and the new generation accelerators of a large duty cycle (CEBAF, MAMI, ESRF, ELF, ...) combined with 4π detectors will allow to precisely measure low cross sections reactions of a large transfer. We first study pion photoproduction reactions on nucleon because they are the most experimentally accessible reactions and many data of high energy and low transfers exist. This will require strong constraints on the model parameters of the numerous analyses performed previously. Then we'll move on to kaon photoproduction

  14. Pion polarizabilities measurement at COMPASS

    CERN Document Server

    Guskov, Alexey

    2008-01-01

    The electromagnetic structure of pions is probed in $\\pi^{−}+(A,Z) \\rightarrow\\pi^{−}+(A,Z)+\\gamma$ Compton scattering in inverse kinematics (Primakoff reaction) and described by the electric ($\\bar{\\alpha_{\\pi}}$) and the magnetic ($\\bar{\\beta_{\\pi}}$) polarizabilities that depend on the rigidity of pion’s internal structure as a composite particle. Values for pion polarizabilities can be extracted from the comparison of the differential cross section for scattering of pointlike pions with the measured cross section. The pion polarizability measurement was performed with a $\\pi^{-}$ beam of 190 GeV. The high beam intensity, the good spectrometer resolution, the high rate capability, the high acceptance and the possibility to use pion and muon beams, unique to the COMPASS experiment, provide the tools to measure precisely the pion polarizabilities in the Primakoff reaction.

  15. Investigation of Compton effect on π-meson and charged pion polarizability

    International Nuclear Information System (INIS)

    Antipov, Yu.M.; Batarin, V.A.; Bezzubov, V.A.

    1986-01-01

    The results of an experiment aimed at the study of the 40 GeV/c pion radiative scattering on nuclei at small momentum transfers are presented. Compton effect on the pion was investigated and the charged pion polarizability was measured. The pion Compton-effect cross section dependence on the incident photon energy ω' 1 (rest pion frame) was measured in the 100 - 600 MeV range. The polarizability of charged pion from the analysis of Compton-effect events has been found to be β π =-α π =(-6.9 ± 1.4 stat. ± 1.2 syst. )x10 -43 cm 3 and the sun of pion electrical α π and magnetic β π polarizability has been estimated to be in agreement with theoretical predictions: α π +β π ≅ 0

  16. Proceedings of the LAMPF workshop on photon and neutral meson physics at intermediate energies

    International Nuclear Information System (INIS)

    Baer, H.W.; Crannell, H.; Peterson, R.J.

    1987-12-01

    This volume contains the Proceedings of the Workshop on ''Photon and Neutral-Meson, Physics at Intermediate Energies,'' held at Los Alamos, New Mexico, January 7 to 9, 1987. The purpose of this workshop was to bring together scientists working in the areas of electromagnetic, heavy-ion, and light hadron physics to discuss both the physics that could be addressed and potential capabilities of new, large intermediate-energy photon detectors. Based on the papers contained in these proceedings, it appears clear that there are a number of important areas that could be addressed with a much higher resolution neutral meson detector. It is also clear that the technical capability for building a neutral meson detector for energies up to 4 GeV with solid angle of approximately 10 mrs and resolution of a few hundred keV now exists. It also appears entirely reasonable to construct such a detector to be easily transportable so that it would become a national facility, available for use at a number of different laboratories. From the many interesting papers presented and from the broad representation of physicists from laboratories in Asia, Canada, Europe, Japan, and the United States, there appears to be a strong case for proceeding with the construction of such a detector

  17. Exclusive electroproduction of two pions at HERA

    CERN Document Server

    Abramowicz, H.

    2012-01-25

    The exclusive electroproduction of two pions in the mass range 0.4 < M{\\pi}{\\pi} < 2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. The analysis was carried out in the kinematic range of 2 < Q2 < 80 GeV2, 32 < W < 180 GeV and |t| < 0.6 GeV2, where Q2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, |F(M{\\pi}{\\pi})|, assuming that the studied mass range includes the contributions of the {\\rho}, {\\rho}' and {\\rho}" vector-meson states. The masses and widths of the resonances were obtained and the Q2 dependence of the cross-section ratios {\\sigma}({\\rho}' \\rightarrow {\\pi}{\\pi})/{\\sigma}({\\rho}) and {\\sigma}({\\rho}" \\rightarrow {\\pi}{\\pi})/{\\sigma}({\\rho}) was extracted. The pion form factor obtained in the present analysis is compared to that obtained...

  18. Exclusive electroproduction of two pions at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Ashery, D.; Gueta, O.; Gurvich, E.; Ingbir, R.; Kananov, S.; Levy, A.; Stern, A.

    2012-01-01

    The exclusive electroproduction of two pions in the mass range 0.4 ππ -1 . The analysis was carried out in the kinematic range of 2 2 2 , 32 2 , where Q 2 is the photon virtuality, W is the photon-proton centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, vertical stroke F(M ππ ) vertical stroke, assuming that the studied mass range includes the contributions of the ρ, ρ' and ρ'' vector-meson states. The masses and widths of the resonances were obtained and the Q 2 dependence of the cross-section ratios σ(ρ'→ππ)/ σ(ρ) and σ(ρ''→ππ)/ σ(ρ) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e + e - →π + π - . (orig.)

  19. Exclusive electroproduction of two pions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-11-15

    The exclusive electroproduction of two pions in the mass range 0.4< M{sub {pi}}{sub {pi}} <2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb{sup -1}. The analysis was carried out in the kinematic range of 2< Q{sup 2}<80 GeV{sup 2}, 32energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, vertical stroke F(M{sub {pi}}{sub {pi}}) vertical stroke, assuming that the studied mass range includes the contributions of the {rho}, {rho}{sup '} and {rho}'' vector-meson states. The masses and widths of the resonances were obtained and the Q{sup 2} dependence of the cross-section ratios {sigma}({rho}{sup '} {yields} {pi}{pi})/{sigma}({rho}) and {sigma}({rho}'' {yields} {pi}{pi})/{sigma}({rho}) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -}. (orig.)

  20. Pion production in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Norbury, J.W.

    1983-01-01

    A Lorentz-invariant differential cross section for pion production in peripheral, relativistic, heavy ion collisions is calculated for the collisions of an 16 O projectile onto a 12 C target. The pions are produced via excitations of a Δ(3,3) resonant state in the projectile with simultaneous excitation of an M1 giant resonance in the target. A second order amplitude describing resonance formation and decay is derived within the context of second order, time-dependent perturbation theory and a corresponding transition rate is evaluated. This is then applied to the problem of pion production and a differential cross section is calculated using a simple product-of-states model. The whole theory is then re-formulated within a second quantized particle-hole model which describes the basic process of M1 giant resonance formation as well as the formation and decay of the intermediate Δ(3,3) resonance. Subsequently, a new Lorentz-invariant differential cross section is calculated from the particle-hole amplitude. The theoretical cross section is compared with some experimental data and the agreement is found to be satisfactory given the nature of the data and the assumptions of the theory

  1. [Studies of target fragmentation in intermediate energy, relativistic and ultra-relativistic nuclear collisions

    International Nuclear Information System (INIS)

    Loveland, W.D.

    1991-08-01

    The work described herein is part of a project involving the study of low energy ( 250 MeV/A) heavy ion reactions. In the low energy regime, we published a monograph on the properties of the heaviest elements and used that publication as a basis for making a set of ''best'' semi-empirical predictions of heavy element decay properties. The intermediate energy research effort focussed upon the completion of studies already begun and the initiation of a number of new experiments. In our study of a interaction of 21 MeV/nucleon 129 Xe with 197 Au, we compared the characteristics of the observed deep inelastic phenomena with various models of dissipative reactions and found significant discrepancies between observations and predictions. These discrepancies seemed to be caused by an improper treatment of pre-equilibrium in the early stages of the collision. In our study of the relativistic interaction of 400 MeV/nucleon 12 C with 197 Au, we reported the first direct physical measurement of the properties of the spallation residues from a nucleus-nucleus collision. We found the residue energies to be much lower than those predicted by the intranuclear cascade model, indicating some substantial modifications of that model are needed. But, we also found, indications of significant, non-zero values of the residue transverse momentum, a finding that calls into question the interpretation of a number of radiochemical recoil studies of the kinematics of high energy reactions. A program of performing numerical simulations of intermediate and high energy nuclear collisions using the QMD model was initiated

  2. Calculation for fission decay from heavy ion reactions at intermediate energies

    International Nuclear Information System (INIS)

    Blaich, T.; Begemann-Blaich, M.; Fowler, M.M.; Wilhelmy, J.B.; Britt, H.C.; Fields, D.J.; Hansen, L.F.; Namboodiri, M.N.; Sangster, T.C.; Fraenkel, Z.

    1992-01-01

    A detailed deexcitation calculation is presented for target residues resulting from intermediate-energy heavy ion reactions. The model involves an intranuclear cascade, subsequent fast nucleon emission, and final decay by statistical evaporation including fission. Results are compared to data from bombardments with Fe and Nb projectiles on targets of Ta, Au, and Th at 100 MeV/nucleon. The majority of observable features are reproduced with this simple approach, making obvious the need for involving new physical phenomena associated with multifragmentation or other collective dissipation mechanisms

  3. A BGO detector array and its application in intermediate energy heavy ion experiments

    International Nuclear Information System (INIS)

    Li Zuyu; Jin Genming; He Zhiyong; Duan Limin; Wu Heyu; Qi Yujin; Luo Qingzheng; Zhang Baoguo; Wen Wanxin; Dai Guangxi

    1996-01-01

    A BGO crystal (Bi 4 Ge 3 O 12 ) as the E detector of ΔE-E for identification of reaction products has been used for detecting the charged particles emitting from the 25 MeV 40 Ar induced reaction. The responses of the BGO crystal to various light charged particles were measured. A close-packed hexagonal array consisting of thirteen ΔE-E telescopes (Si-BGO) has been developed to detect the light charged particles interfering with each other in intermediate-energy heavy-ion induced reactions. Some applications of this telescope array are also described. (orig.)

  4. Intercomparison of codes for intermediate energy nuclear data: The first step

    International Nuclear Information System (INIS)

    Blann, M.; Gruppelaar, H.; Nagel, P.; Rodens, J.

    1994-01-01

    Several weak points of the intermediate energy nuclear data calculated in this exercise are described as introduction to some of the areas needing discussion at this meeting. These include nuclear structure effects on precompound spectra, large variations between codes in predicted total reaction cross sections, and in total neutron and proton multiplicities. INC codes don't reflect correct experimental Q values, and may have difficulties at very low angles due to overestimation of the quasi-elastic peak. We raise questions as to additional reaction properties (beyond n and p spectra) which may need benchmarking

  5. Single electron capture differential cross section in H+ + He collisions at intermediate and high collision energies

    International Nuclear Information System (INIS)

    Abufager, P N; Fainstein, P D; MartInez, A E; Rivarola, R D

    2005-01-01

    The generalized continuum distorted wave-eikonal initial state (CDW-EIS II) approximation is employed to study differential cross sections (DCS) for single electron capture in H + + He collisions at intermediate and high energies. Present results are compared with theoretical calculations obtained using the previous CDW-EIS formulation in order to show the importance of the description of the bound and continuum target states in the entrance and exit channels, respectively. Both DCS are also shown together with other theoretical results and with experimental data

  6. A Monte Carlo method for nuclear evaporation and fission at intermediate energies

    International Nuclear Information System (INIS)

    Deppman, A.; Likhachev, V.P.; Mesa, J.; Pina, S.R. de; Arruda-Neto, J.D.T.; Goncalves, M.; Rodriguez, O.

    2003-04-01

    We describe a Monte Carlo method to calculate the characteristics of the competition between particle evaporation and nuclear fission processes taking place in the compound nucleus formed after the intranuclear cascade following the absorption of intermediate energy photons by the nucleus. In this version we include not only neutrons, but also protons and alphas as possible evaporating particles. However, this method allows an ease inclusion of other evaporating particles, as deuteron or heavier clusters. Some results for 237 Np, 238 U, and 232 Th are shown. (author)

  7. A Monte Carlo method for nuclear evaporation and fission at intermediate energies

    International Nuclear Information System (INIS)

    Deppman, A.; Tavares, O.A.P.; Duarte, S.B.; Arruda-Neto, J.D.T.; Goncalves, M.; Likhachev, V.P.; Mesa, J.; Oliveira, E.C. de; Pina, S.R. de; Rodriguez, O.

    2003-01-01

    We describe a Monte Carlo method to calculate the characteristics of the competition between particle evaporation and nuclear fission processes taking place in the compound nucleus formed after the intranuclear cascade following the absorption of intermediate energy photons by the nucleus. In this version we include not only neutrons, but also protons and alphas as possible evaporating particles. The present method allows the easy inclusion of other evaporating particles, such as deuteron or heavier clusters. Some fissility results are discussed for the target nuclei 237 Np, 238 U and 232 Th

  8. Quark-exchange effects in a deuteron breakup at intermediate energy

    International Nuclear Information System (INIS)

    Kobushkin, A.P.; Syamtomov, A.I.; Glozman, L.Ya.

    1995-01-01

    Microscopical approach to a deuteron breakup at high and intermediate energies is proposed. We show that the quark exchange effects, resulting from the full asymmetry of the 6q-deuteron wave function with respect to the pair permutations of quark variables, strongly affect the proton momentum distribution in the deuteron, as well as the polarization observables of inclusive deuteron breakup, when the '' internal momentum '' in the deuteron is of order of a few hundreds MeV/c. 25 refs., 2 tab., 9 figs

  9. Quark-exchange effects in a deuteron breakup at intermediate energy.

    Energy Technology Data Exchange (ETDEWEB)

    Kobushkin, A P; Syamtomov, A I; Glozman, L Ya

    1996-12-31

    Microscopical approach to a deuteron breakup at high and intermediate energies is proposed. We show that the quark exchange effects, resulting from the full asymmetry of the 6q-deuteron wave function with respect to the pair permutations of quark variables, strongly affect the proton momentum distribution in the deuteron, as well as the polarization observables of inclusive deuteron breakup, when the `` internal momentum `` in the deuteron is of order of a few hundreds MeV/c. 25 refs., 2 tab., 9 figs.

  10. MCNP6 Fission Cross Section Calculations at Intermediate and High Energies

    OpenAIRE

    Mashnik, Stepan G.; Sierk, Arnold J.; Prael, Richard E.

    2013-01-01

    MCNP6 has been Validated and Verified (V&V) against intermediate- and high-energy fission cross-section experimental data. An error in the calculation of fission cross sections of 181Ta and a few nearby target nuclei by the CEM03.03 event generator in MCNP6 and a "bug: in the calculation of fission cross sections with the GENXS option of MCNP6 while using the LAQGSM03.03 event generator were detected during our V&V work. After fixing both problems, we find that MCNP6 using CEM03.03 and LAQGSM...

  11. Probing in-medium spin–orbit interaction with intermediate-energy heavy-ion collisions

    International Nuclear Information System (INIS)

    Xu, Jun; Li, Bao-An

    2013-01-01

    Incorporating for the first time both the spin and isospin degrees of freedom explicitly in transport model simulations of intermediate-energy heavy-ion collisions, we observe that a local spin polarization appears during collision process. Most interestingly, it is found that the nucleon spin up–down differential transverse flow is a sensitive probe of the spin–orbit interaction, providing a novel approach to probe both the density and isospin dependence of the in-medium spin–orbit coupling that is important for understanding the structure of rare isotopes and synthesis of superheavy elements

  12. A liquid He-3 target system for use at intermediate energies

    International Nuclear Information System (INIS)

    Hassell, D.K.; Abegg, R.; Murdoch, B.T.; van Oers, W.J.H.; Soukup, J.

    1981-04-01

    A liquid 3 He target system with remote instrumentation and handling capabilities has been developed for experiments using the 180-525 MeV TRIUMF cyclotron. Helium-3 gas is liquefied by means of a 4 He cryostat into a cylindrical target cell (4.4 cm diameter, 1.6 cm thick) and maintained during operation at approximately 1.6 K. This provides an areal target density of approximately 2.7 x 10 22 He-3 nuclei/cm 2 (128 mg/cm 2 ), suitable for intermediate energy proton scattering. (author)

  13. Production of nuclei far from the beta stability line using intermediate-energy heavy ions

    International Nuclear Information System (INIS)

    Guerreau, D.

    1986-05-01

    The production of far unstable nuclei using heavy ion accelerators in the intermediate energy domain is reviewed. The various mechanisms responsible for the production of exotic species, mainly the projectile fragmentation and transfer reactions, are discussed, and the first experimental results presented. Results can be summarized as follows: existence of 4 new isotopes 22 C, 23 N, 29 Ne, 30 Ne; indication of bound character of 71 Ni, 72 Ni; clear evidence for bound character of 23 Si, 27 S, 31 Ar, 35 Ca; indications of bound character of 43 V, 46 Mn, 47 Mn, 48 Fe, 50 Co, 52 Co, 52 Ni, 55 Cu, 56 Cu

  14. Differential cross sections for inelastic scattering of electrons on Kr and Xe atoms at intermediate energies

    International Nuclear Information System (INIS)

    Filipovic, D.M.

    1989-01-01

    Electron-impact excitation of the larger- number noble-gas atoms is a way of understanding excitation mechanisms in atomic collisional processes. Krypton and xenon have the largest atomic number of all the stable noble gases. Therefore, effects dependent on the size of a target atom, such as alignment and orientation of the atomic outer shell charge cloud after collisional excitation, are best observed by studying these atoms. Normalized, absolute differential cross sections (DCS's) for the lowest electronic states of Kr and Xe atoms, at intermediate energies, are the subject of this report

  15. Non-Regge and hyper-Regge effects in pion-nucleon charge exchange scattering at high energies

    International Nuclear Information System (INIS)

    Joynson, D.; Leader, E.; Nicolescu, B.; Paris-6 Univ., 75; Lopez, C.

    1975-04-01

    The experimental data on the charge exchange differential cross-section and on the difference on the π + p and π - p total cross-sections between 5GeV/c to 200GeV/c are shown to be incompatible with conventional Regge asymptotic behavior. It is shown that an additional term is required which grows in importance with energy. The precise form of the new term cannot be ascertained, but it is shown that it corresponds to a singularity at J=1 in the complex angular momentum plane. Amongst the possible types of additional term there are two which have been closely analysed: a non-Regge behavior, a hyper-Regge term which have allowed very striking predictions in particular for the charge exchange polarisation [fr

  16. Exclusive electroproduction of pion pairs

    International Nuclear Information System (INIS)

    Warkentin, N.; Schaefer, A.; Diehl, M.; Ivanov, D. Yu.

    2007-01-01

    We investigate electroproduction of pion pairs on the nucleon in the framework of QCD factorization for hard exclusive processes. We extend previous analyses by taking the hard-scattering coefficients at next-to-leading order in α s . The dynamics of the produced pion pair is described by two-pion distribution amplitudes, for which we perform a detailed theoretical and phenomenological analysis. In particular, we obtain constraints on these quantities by comparing our results with measurements of angular observables that are sensitive to the interference between two-pion production in the isoscalar and isovector channels. (orig.)

  17. Spectator-velocity pions from heavy ions

    International Nuclear Information System (INIS)

    Rasmussen, J.; Ridout, J.; Murphy, D.; Radi, H.M.A.

    1982-11-01

    The discussion centers on pions in the velocity regions of target and projectile, where strong spectral features appear. The topics covered include stopped-pion studies, and convoy pions in the projectile frame

  18. Effects of the pion string at heavy ion collisions

    International Nuclear Information System (INIS)

    Mao Hong; Li Yunde; East China Normal Univ., Shanghai

    2005-01-01

    The authors study the possible signals of the pion string associated with the QCD chiral phase transition in LHC Pb-Pb collision at energy √s=5.5 TeV. The authors follow the Kibble-Zurek mechanism to discuss the production and evolution of the pion string. The authors will show that if the QCD chiral phase transition really takes place in the LHC Pb-Pb collision process and the phase transition is in the second order, the pion string will be inevitably produced and subsequently decay. The main effect of this phenomenon is that there is a generation of a large number of pions in the final state produced by the decay of the pion string, and these pions are mostly distributed in a low momentum region with p-143 MeV; also there are lots of neutral pions distributed in a low momentum region with the mean momentum at p-21 MeV. (authors)

  19. Pion interactions with light nuclei and applications to radiotherapy

    International Nuclear Information System (INIS)

    Brenner, D.J.

    1979-02-01

    In the light of the current interest in negative pion radiotherapy particle spectra have been obtained after negative pion absorption in oxygen. Using a multiple foil activation technique, measurements were made of neutron spectra from the pion interactions and also from background sources from which it appears that the technique is a potentially useful tool for routine dosimetry. Theoretical predictions are made of the energy spectra of particles emitted after stopped pion absorption on oxygen based on an alpha cluster model and using a plane-wave impulse approximation. A method of considering residual interactions with the nucleus is described which has the potential to treat the low energy particles and also final channels not expected as a result of a single interaction. (UK)

  20. Deeply virtual compton scattering on a virtual pion target

    International Nuclear Information System (INIS)

    Amrath, D.; Diehl, M.; Lansberg, J.P.; Heidelberg Univ.

    2008-07-01

    We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations. (orig.)

  1. Thermodynamics of pion gas using states predicted from κ-deformed Poincare algebra

    International Nuclear Information System (INIS)

    Cordeiro, Claudete E.; Delfino, Antonio; Dey, Jishnu

    1995-01-01

    K-deformed Poincare algebra, which preserves rotational and translational symmetries, can successfully predict the angular and radial excited states of the pion. At high temperature, T these states can be excited in the pion gas, in addition to the usual momentum excitation. We exploit this to look at pion free energy finding it increases linearly with T. The energy per particle and the entropy show evidence of a smooth phase transition after T=0.2 GeV. (author)

  2. Excitation energy of the fragments produced in central collisions of Xe + Sn at intermediate energies

    International Nuclear Information System (INIS)

    Hudan, S.; Chbihi, A.; Frankland, J.D.

    2000-01-01

    Characteristics of the primary fragments produced in central collisions of Xe + Sn system from 32 to 50 AMeV have been deduced. By using the relative velocity correlation technique between the light charged particles (LCP) and detected fragments, we were able to extract the multiplicities and average kinetic energy of the secondary evaporated LCP. We then reconstructed the size and excitation energy of the primary fragments. For each bombarding energy a constant value of the excitation energy per nucleon, over the whole range of fragment charge has been found, suggesting that on the average thermodynamical equilibrium has been achieved at the freeze-out. This value increases slightly from 2.8 to 3.8 AMeV with a large increase of bombarding energy, 32 to 50 AMeV. (authors)

  3. Excitation energy of the fragments produced in central collisions of Xe + Sn at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Hudan, S.; Chbihi, A.; Frankland, J.D. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)] [and others

    2000-07-01

    Characteristics of the primary fragments produced in central collisions of Xe + Sn system from 32 to 50 AMeV have been deduced. By using the relative velocity correlation technique between the light charged particles (LCP) and detected fragments, we were able to extract the multiplicities and average kinetic energy of the secondary evaporated LCP. We then reconstructed the size and excitation energy of the primary fragments. For each bombarding energy a constant value of the excitation energy per nucleon, over the whole range of fragment charge has been found, suggesting that on the average thermodynamical equilibrium has been achieved at the freeze-out. This value increases slightly from 2.8 to 3.8 AMeV with a large increase of bombarding energy, 32 to 50 AMeV. (authors)

  4. Power corrections to the asymptotics of the pion electromagnetic formfactor

    International Nuclear Information System (INIS)

    Gorsky, A.S.

    1984-01-01

    The first power correction to the pion electromagnetic form factor is derived. A few asymptotic wave functions corresponding to the different series of operators and matrix elements of four-particle operators in pion have been found. The large scale of the first power correction approximately 10 2 (GeV 2 )/Q 2 where Q 2 is the momentum transfer indicates that at low energies the whole series of power corrections seems to be taken into account

  5. A relativistic, meson exchange model of pion-nucleon scattering

    International Nuclear Information System (INIS)

    Pearces, B.C.; Jennings, B.K.

    1990-06-01

    A relativistic meson exchange approach to the pion-nucleon interaction is developed using a three-dimensional relativistic two-body propagator, and the results using different propagators are compared. The relativistic approach is able to describe low energy scattering up to 400 MeV above threshold, while preserving the soft pion theorems. The different propagators give similar results, as the form factors necessary to get a fit suppress much of the multiple scattering. (Author) (24 refs., 4 tabs., 6 figs.)

  6. Quantum mechanical signature in exclusive coherent pion production

    Science.gov (United States)

    Deutchman, P. A.; Buvel, R. L.; Maung, K. M.; Norbury, J. W.; Townsend, L. W.

    1986-01-01

    We calculate the coherent production of pions from subthreshold to relativistic energies in heavy-ion collisions using a quantum, microscopic, many-body model. For the first time, in this approach, we use harmonic oscillator wave functions to describe shell-model information. The theoretical quantum mechanical results obtained for the pion spectra represent an important improvement over our previous microscopic, many-body calculations.

  7. Peripheral collisions of heavy ions induced by 40Ar at intermediate energies: giant resonance high energy structures and projectile fragmentation

    International Nuclear Information System (INIS)

    Blumenfeld, Y.

    1987-09-01

    The results obtained in similar studies at low incident energies are first of all reviewed. The time of flight spectrometer built for the experiments is then described. A study of the properties of the projectile-like fragments shows numerous deviations from the relativistic energy fragmentation model. Evidence for a strong surface transfer reaction component is given and the persistence of mean field effects at intermediate energies is stressed. A calculation of the contribution of the transfer evaporation mechanism to the inelastic spectra shows that this mechanism is responible for the major part of the background measured at high excitation energy and can in some cases induce narrow structures in the spectra. The inelastic spectra shows a strong excitation of the giant quadrupole resonance. In the region between 20 and 80 MeV excitation energy narrow structures are present for all the studied systems. Statistical and Fourier analysises allow to quantify the probabilities of existence, the widths and the excitation energies of these structures. A transfer evaporation hypothesis cannot consistently reproduce all the observed structures. The excitation energies of the structures can be well described by phenomenological laws where the energies are proportional to the -1/3 power of the target mass. Complete calculations of the excitation probabilities of giant resonances and multiphonon states are performed within a model where the nuclear excitation are calculated microscopically in the Random Phase Approximation. It is shown that a possible interpretation of the structures is the excitation of multiphonon states built with 2 + giant resonances [fr

  8. Pions in nuclei, from virtual-pion exchange to real-pion transfer

    International Nuclear Information System (INIS)

    Yamazaki, Toshimitsu.

    1988-07-01

    Tracing the work of Miyazawa on nuclear magnetic moments, we discuss possible experimental ways to see whether a real pion exists in nuclei or not. While virtual pions are known to play an important role in nuclei, as clarified experimentally from anomalous orbital g factors of nucleons in nuclei, nearly nothing is known for the behavior of real pions in nuclei. We have shown that deeply bound hybrid states of π - are expected to exist in heavy nuclei, which can be populated by ''pion transfer'' reactions. (author)

  9. Inclusive quasielastic neutrino reactions in 12C and 16O at intermediate energies

    International Nuclear Information System (INIS)

    Singh, S.K.; Oset, E.

    1993-01-01

    Inclusive quasielastic neutrino (antineutrino) reactions on 12 C and 16 O at intermediate energies (50< E<400 MeV) are studied to investigate the effects of the nuclear medium on the total cross section and the energy spectrum of the outgoing leptons. The calculations are done in the local density approximation and various nuclear effects like Pauli blocking, Fermi motion, and strong-interaction renormalizations due to the presence of nucleons are taken into account. The corrections due to Coulomb effects are included which have been hitherto neglected in inclusive reactions. The results presented here are applicable to the inclusive reactions with neutrino beams planned to look for neutrino oscillations in the Los Alamos experiments or the experiments with underground detectors looking for atmospheric or solar flare neutrinos

  10. Progress in applyiong the FKK multistep reaction theory to intermediate-energy data evaluation

    International Nuclear Information System (INIS)

    Chadwick, M.B.; Young, P.G.

    1994-01-01

    Recent developments to the physics modeling in the FKK-GNASH code system are reviewed. We describe modifications to include a linking of multistep direct and multistep compound processes, which are important when the incident energy is less than about 30 MeV. A model for multiple preequilibrium emission is given, and compared with experimental measurements of proton reactions on 90 Zr at 160 MeV. We also give some preliminary observations concerning FKK calculations which use both normal and non-normal DWBA matrix elements. We describe the application of the FKK-GNASH code to a range of nuclear data applications, including intermediate energy reactions of importance in the accelerator transmutation of waste, and fast neutron and proton cancer radiation treatment. We outline areas where further work is needed for the accurate modeling of nuclear reactions using the FKK theory

  11. Intermediate energy heavy ions: An emerging multi-disciplinary research tool

    International Nuclear Information System (INIS)

    Alonso, J.R.

    1988-10-01

    In the ten years that beams of intermediate energy (∼50 MeV/amu≤E≤∼2 GeV/amu) heavy ions (Z≤92) have been available, an increasing number of new research areas have been opened up. Pioneering work at the Bevalac at the Lawrence Berkeley Laboratory, still the world's only source of the heaviest beams in this energy range, has led to the establishment of active programs in nuclear physics, atomic physics, cosmic ray physics, as well as biology and medicine, and industrial applications. The great promise for growth of these research areas has led to serious planning for new facilities capable of delivering such beams; several such facilities are now in construction around the world. 20 refs., 5 figs., 1 tab

  12. Evolution of collectivity in the 78Ni region: Coulomb excitation of 74Ni at intermediate energies.

    Directory of Open Access Journals (Sweden)

    Marchi T.

    2014-03-01

    Full Text Available The study of the collective properties of nuclear excitations far from stability provides information about the shell structure at extreme conditions. Spectroscopic observables such as the energy or the transition probabilities of the lowest states, in nuclei with large neutron excess, allow to probe the density and isospin dependence of the effective interaction. Indeed, it was recently shown that tensor and three-body forces play an important role in breaking and creating magic numbers. Emblematic is the case of the evolution of the Ni isotopic chain where several features showed up moving from the most neutron rich stable isotope (64Ni towards the 78Ni nucleus where the large neutron excess coincides with a double shell closure. In this framework, we have recently performed an experiment with the goal to extract the B(E2; 0+ → 2+ value for the 74Ni nucleus in an intermediate-energy Coulomb excitation experiment: preliminary results are discussed.

  13. Photon and proton induced fission on heavy nuclei at intermediate energies

    Directory of Open Access Journals (Sweden)

    Andrade-II E.

    2014-04-01

    Full Text Available We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on 241Am, 238U, and 237Np targets and the Bremmstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on 232Th and 238U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments.

  14. Photon and proton induced fission on heavy nuclei at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Andrade-II, E.; Karapetyan, G.S.; Deppman, A.; Guimaraes, V. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Balabekyan, A.R. [Yerevan State University, Alex Manoogian 1, Yerevan (Armenia); Demekhina, N.A. [Yerevan Physics Institute, Alikhanyan Brothers 2, Yerevan (Armenia); Joint Institute for Nuclear Research (JINR), Flerov Laboratory of Nuclear Reactions (LNR), Moscow (Russian Federation)

    2014-07-01

    We present an analysis of fission induced by intermediate energy protons or photons on actinides. The 660 MeV proton induced reactions are on {sup 241}Am, {sup 238}U, and {sup 237}Np targets and the Bremsstrahlung-photons with end-point energies at 50 MeV and 3500 MeV are on {sup 232}Th and {sup 238}U targets. The study was performed by means of the Monte Carlo simulation code CRISP. A multimodal fission extension was added to the code within an approach which accounts for the contribution of symmetric and asymmetric fission. This procedure allowed the investigation of fission cross sections, fissility, number of evaporated nucleons and fission-fragment charge distributions. The comparison with experimental data show a good agreement between calculations and experiments. (author)

  15. Nuclear structure at intermediate energies: Progress report, November 1986-August 1987

    International Nuclear Information System (INIS)

    Bonner, B.E.; Mutchler, G.S.; Phillips, G.C.

    1987-01-01

    The report includes information on prior, current, and future experiments; nuclear theory; and instrumentation. Current experiments include single pion production in np scattering, spin transfer in hyperon production, photoproduction of high p/sub T/jets, and meson studies. Future experiments will continue current research and also include the production of lambda particles with heavy ions and the production of polarized antiproton beams at LEAR. Theoretical research programs are investigating the Gaussian effective potential (GEP), hadron-nucleus scattering as a function of nuclear size, nucleon structure, and exotic contributions to lambda production in pion-deuteron interactions. Instrumentation developments include proportional wire counters, other electronics, and computer systems. 13 refs., 1 tab

  16. Relativistic three-body approach to NN scattering at intermediate energies

    International Nuclear Information System (INIS)

    van Faassen, E.; Tjon, J.A.

    1986-01-01

    The Bethe-Salpeter equation for coupled-channel N-Δ scattering is extended to satisfy unitarity in the NN and NNπ sectors. The procedure eliminates the unitarity violations characteristic of the standard ladder Bethe-Salpeter equation in the inelastic region, and improves the description of pion production near threshold. Results are presented for the NN phase shift and a number of observables up to 1 GeV. In particular, the 1D 2 inelasticity is found to be considerably smaller than found from phase shift analysis. In this context, the importance of the pion deuteron channel for the inelasticity parameter of is pointed out. 33 refs., 16 figs., 4 tabs

  17. Investigation of incomplete linear momentum transfer in heavy ion reactions at intermediate energies

    International Nuclear Information System (INIS)

    Leray, S.

    1986-07-01

    At intermediate energies, heavy ion central collisions lead to the incomplete fusion of the incident nuclei while part of the initial linear momentum is carried away by fast light particles. Experiments were performed with 30 MeV per nucleon neon and 20, 35 and 44 MeV per nucleon argon projectiles bombarding heavy targets. Results obtained with 30 MeV per nucleon neon and 20 MeV per nucleon argon beams are in good agreement with an empirical law established with lighter projectiles. On the contrary, 35 and 44 MeV per nucleon argon projectiles do not follow the same law and fission fragments progressively disappear. A simple model explains the evolution of the amount of transferred linear momentum versus incident energy. The disappearance of the fusion products of the composite system observed with argon projectiles beyond 35 MeV per nucleon is explained by a limitation of the excitation energy per nucleon which can be deposited in a nucleus. The limit is evaluated from nucleon binding energy in nuclei and probability to emit clusters and is in good agreement with experimental data. Because of the coupling between intrinsic motion of nucleons and relative motion of nuclei, some nucleons have a kinetic energy high enough to be emitted: a theoretical model is proposed which rather well fits the data concerning fast nucleons but cannot explain the measured amounts of transferred linear momentum. This is attributed to the existence of other mechanisms [fr

  18. BioBoost. Biomass based energy intermediates boosting bio-fuel production

    Energy Technology Data Exchange (ETDEWEB)

    Niebel, Andreas [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Institut fuer Katalyseforschung und -technologie (IKFT)

    2013-10-01

    To increase the share of biomass for renewable energy in Europe conversion pathways which are economic, flexible in feedstock and energy efficient are needed. The BioBoost project concentrates on dry and wet residual biomass and wastes as feedstock for de-central conversion by fast pyrolysis, catalytic pyrolysis and hydrothermal carbonization to the intermediate energy carriers oil, coal or slurry. Based on straw the energy density increases from 2 to 20-30 GJ/m{sup 3}, enabling central GW scale gasification plants for bio-fuel production. A logistic model for feedstock supply and connection of de-central with central conversion is set up and validated allowing the determination of costs, the number and location of de-central and central sites. Techno/economic and environmental assessment of the value chain supports the optimization of products and processes. The utilization of energy carriers is investigated in existing and coming applications of heat and power production and synthetic fuels and chemicals. (orig.)

  19. Photoproduction of mesons on the nucleon at intermediate energies; Photoproduction de mesons sur le nucleon aux energies intermediaires

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, M

    1997-01-01

    In this work a model is proposed to simulate the photoproduction of pseudoscalar mesons ('PI' and K) on the nucleon at high energy. This model is based on the exchange of mesonic or baryonic Regge trajectories, it is gauge invariant and it uses a Feynman diagram formalism inspired from isobaric models. The measurements concerning the following reactions {gamma}p {yields} n{pi}{sup +}, {gamma}n {yields} p{pi}{sup -}, {gamma}p {yields} p{pi}{sup 0} and {gamma}n {yields} n{pi}{sup 0} are reviewed and the new model is confronted to the experimental results. The model gives a reasonable and coherent description of these 4 reactions. The model has also been applied to the photoproduction of strange mesons and of {lambda} and {sigma} baryons and has been extrapolated at low energy to the threshold of the reaction, the model matches the results even up to E{sub {gamma}} = 2 GeV for differential cross-sections and recoil polarization. An attempt has been made to associate a Regge based description, which is valid with low transfers, with perturbative quantum chromodynamics which is valid with high transfers. The model relies on the saturation of trajectories in the high transfer region and on the counting laws that give the right variation of the cross-section. It seems that a model based on linear trajectories can be reliable up to 4 GeV. The domain of high transfer has been too little investigated to provide enough experimental data to validate the model. An experiment whose purpose is to study the photoproduction of {phi} at high transfer, is proposed. This experiment requires an accelerator with high useful cycle because of the smallness of the expected cross-section. The CEBAF (continuous electron beam accelerator facility) as well as the CLAS 4{pi} detector is presented. The study of {gamma}p {yields} p{phi} and {gamma}p {yields} K{lambda}{sup *} (1520) requires the discrimination of kaons from pions so the measurement of 180 ps as time resolution allows the

  20. Visual sensations induced by relativistic pions

    International Nuclear Information System (INIS)

    McNulty, P.J.; Pease, V.P.; Bond, V.P.

    1976-01-01

    Visual sensations were experienced when bursts of high-energy pions passed through the dark-adapted right eyes of three human subjects. The threshold for a visual sensation was typically 1 to 3 μrad at the retina. Data are presented to show that the mechanism is Cerenkov radiation generated within the vitreous humor. Threshold measurements agree with published optical data. A comparison is made between our observations and the light flashes observed in deep space by Apollo astronauts