Jets in high energy nucleon-nucleon collisions
International Nuclear Information System (INIS)
Strugalski, Z.
1982-01-01
From the experimental studies of high-energy hardon-nucleon and nucleon-nucleon collisions, by means of nuclear targets applied as detectors, it follows that particles are produced via intermediate objects created first in a 2 → 2 type endoergic reaction. These objects, called generons, decay in flight into finally observed particles and resonances after their lifetime tausub(g) > or approximately 10 - 22 s. The jet structure of the outcome in nucleon-nucleon collisions is a simple and indispensable consequence of this particle production mechanism. The picture of the jet structure in the collision outcome observed in the CMS of the colliding nucleons depends on the energy of these nUcleons. New particle production scheme is proposed, which can be tested experimentally; corresponding simple relations between characteristics of colliding nucleons and of produced jets are proposed for a testing
High energy nucleonic component of cosmic rays at mountain altitudes
Stora, Raymond Félix
The diffusion equations describing the unidimensional propagation of .the high energy nucleonic component of cosmic rays throughout the atmosphere are sol"V'ed under two assumptions: (l) The nucleon-nucleon collisions are described according to Fermi's therlnOdynamical model involving completely inelastic pion and.nucleon-antinucleon pair production. (2) A somewhat opposite assumption is made assuming partially elastic collisions without nucleon-anti.nucleon pair production. Due to the present inaccuracy of experiments, we are able to derive only tentati v.e conclusions. The values computed under both hypotheses for the absorption mean free path and the charged to neutral particles ratio are found in acceptable ranges when compared to experimental data. The diffeential energy spectrum at a given depth is always found steeper than the primary, and steeper than indicated by experimental values if the primary is taken proportional to the 2.5 inverse power of energy.
Lepton-nucleon scattering at high energies
International Nuclear Information System (INIS)
Buchmueller, W.
1993-12-01
Recent theoretical developments in the field of inelastic lepton-nucleon scattering are reviewed with emphasis on physics at HERA. Structure functions at small Bjorken-x are discussed in detail. Further topics are photoproduction of jets, the gluon densities in proton and photon, charm physics, electroweak processes and the search for new particles and interactions. (orig.)
Pi-nucleon phenomenology at high energies
International Nuclear Information System (INIS)
Kogitz, S.
1973-01-01
A brief introduction to the phenomenology of strong interactions at high energy is presented. This includes discussion of the topics including absorption, finite energy sum rules, and duality. The application of these ideas to two-particle inelastic reactions is examined. (author)
Current status of high energy nucleon-meson transport code
Energy Technology Data Exchange (ETDEWEB)
Takada, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
Current status of design code of accelerator (NMTC/JAERI code), outline of physical model and evaluation of accuracy of code were reported. To evaluate the nuclear performance of accelerator and strong spallation neutron origin, the nuclear reaction between high energy proton and target nuclide and behaviors of various produced particles are necessary. The nuclear design of spallation neutron system used a calculation code system connected the high energy nucleon{center_dot}meson transport code and the neutron{center_dot}photon transport code. NMTC/JAERI is described by the particle evaporation process under consideration of competition reaction of intranuclear cascade and fission process. Particle transport calculation was carried out for proton, neutron, {pi}- and {mu}-meson. To verify and improve accuracy of high energy nucleon-meson transport code, data of spallation and spallation neutron fragment by the integral experiment were collected. (S.Y.)
Inelastic nucleon diffraction at high energy
International Nuclear Information System (INIS)
Goggi, G.
1975-01-01
Experiments carried out at ISR and at FNAL which have yielded a substantial amount of data on double diffraction processes, which were unambiguously indentified and measured and which provide new tools to study the dynamical properties shared by different classes of diffractive reactions are identified. In this review interest is focused on the experimental aspects of inclusive and exclusive results both on single and double diffraction and on the problems arising from their comparison. Problems covered include; inclusive and semi-inclusive diffraction, multiparticle inclusive studies, single-particle inclusive studies, resonance region, high mass region, exclusive single diffractive reactions, mass spectra, cross sections, t-dependence, decay angular properties, and double diffraction. (U.K.)
Theoretical aspects of high energy elastic nucleon scattering
Kundrat, Vojtech; Lokajicek, Milos
2010-01-01
The eikonal model must be denoted as strongly preferable for the analysis of elastic high-energy hadron collisions. The given approach allows to derive corresponding impact parameter profiles that characterize important physical features of nucleon collisions, e.g., the range of different forces. The contemporary phenomenological analysis of experimental data is, however, not able to determine these profiles unambiguously, i.e., it cannot give the answer whether the elastic hadron collisions are more central or more peripheral than the inelastic ones. However, in the collisions of mass objects (like protons) the peripheral behavior of elastic collisions should be preferred.
On the angular distribution of spectator nucleons in high-energy collisions with deuterium nuclei
International Nuclear Information System (INIS)
Bartke, J.
1975-01-01
Angular distributions of spectator nucleons in collisions of high-energy particles with deuterium nuclei are discussed in the framework of the impulse model. Comparison with experimental data shows that predictions following from this simple theoretical model are verified by experiment. Some general remarks on the study of angular distributions of spectator nucleons are given. (author)
HETFIS: High-Energy Nucleon-Meson Transport Code with Fission
International Nuclear Information System (INIS)
Barish, J.; Gabriel, T.A.; Alsmiller, F.S.; Alsmiller, R.G. Jr.
1981-07-01
A model that includes fission for predicting particle production spectra from medium-energy nucleon and pion collisions with nuclei (Z greater than or equal to 91) has been incorporated into the nucleon-meson transport code, HETC. This report is primarily concerned with the programming aspects of HETFIS (High-Energy Nucleon-Meson Transport Code with Fission). A description of the program data and instructions for operating the code are given. HETFIS is written in FORTRAN IV for the IBM computers and is readily adaptable to other systems
Atomic Nuclei Utter Disintegration into Nucleons by High Energy Nuclear Projectiles
International Nuclear Information System (INIS)
Strugalski, Z.
1994-01-01
The disintegration process of atomic nuclei by high energy nuclear projectiles is described. The physical basis for this process is the passage of hadrons through layers of intranuclear matter accompanied by the nucleon emission from the target nuclei observed in experiments; kinetic energies of the nucleons are from about 20 up to about 400 MeV - in the target nucleus reference system. 22 refs., 3 tabs
High-Energy antipp and pp Elastic Scattering and Nucleon Structure
International Nuclear Information System (INIS)
Islam, M.M.; Innocente, V.; Fearnley, T.; Sanguinetti, G.
1987-01-01
High-energy antipp and pp elastic data from the CERN Collider and the ISR are analyzed in the nucleon valence core model. Diffraction is described by a profile function that incorporates crossing symmetry and saturation of Froissart-Martin bound. The model is found to provide a very satisfactory description of the elastic scattering over the whole range of energy and momentum transfer. Implications of the analysis on QCD models of nucleon structure are pointed out
High-Energy antipp and pp Elastic Scattering and Nucleon Structure
Energy Technology Data Exchange (ETDEWEB)
Islam, M.M.; Innocente, V.; Fearnley, T.; Sanguinetti, G.
1987-07-15
High-energy antipp and pp elastic data from the CERN Collider and the ISR are analyzed in the nucleon valence core model. Diffraction is described by a profile function that incorporates crossing symmetry and saturation of Froissart-Martin bound. The model is found to provide a very satisfactory description of the elastic scattering over the whole range of energy and momentum transfer. Implications of the analysis on QCD models of nucleon structure are pointed out.
Measurement of the nucleon structure function using high energy muons
International Nuclear Information System (INIS)
Meyers, P.D.
1983-12-01
We have measured the inclusive deep inelastic scattering of muons on nucleons in iron using beams of 93 and 215 GeV muons. To perform this measurement, we have built and operated the Multimuon Spectrometer (MMS) in the muon beam at Fermilab. The MMS is a magnetized iron target/spectrometer/calorimeter which provides 5.61 kg/cm 2 of target, 9% momentum resolution on scattered muons, and a direct measure of total hadronic energy with resolution sigma/sub nu/ = 1.4√nu(GeV). In the distributed target, the average beam energies at the interaction are 88.0 and 209 GeV. Using the known form of the radiatively-corrected electromagnetic cross section, we extract the structure function F 2 (x,Q 2 ) with a typical precision of 2% over the range 5 2 2 /c 2 . We compare our measurements to the predictions of lowest order quantum chromodynamics (QCD) and find a best fit value of the QCD scale parameter Λ/sub LO/ = 230 +- 40/sup stat/ +- 80/sup syst/ MeV/c, assuming R = 0 and without applying Fermi motion corrections. Comparing the cross sections at the two beam energies, we measure R = -0.06 +- 0.06/sup stat/ +- 0.11/sup syst/. Our measurements show qualitative agreement with QCD, but quantitative comparison is hampered by phenomenological uncertainties. The experimental situation is quite good, with substantial agreement between our measurements and those of others. 86 references
Studies of high energy lepton-nucleon scattering
International Nuclear Information System (INIS)
Ingelman, G.
1982-05-01
The first part of this thesis is related to the problem of detecting charmed particles. A new technique for observing very short decay paths in nuclear emulsions is developed and applied on a sample of neutrino induced reactions. Techniques for producing thick pellicles of nuclear track emulsion are also developed. In the second part, phenomenological investigations of deep inelastic lepton-nucleon scattering are made. Monte Carlo computer programs, based on the parton model and perturbative QCD for the initial hard process and the Lund model for the following soft hadronization, are used to simulate these reactions and thereby obtain explicit results. Generally good agreement is found when comparing these with experimental data, thus supporting this basic framework. Predictions to test QCD are made. Transverse momentum properties are studied in detail, in particular effects from soft gluon emission. The properties of a model for baryon production, both from the target remnant and the colour force field, are discussed and the results found to agree with data. It is shown that, at the presently available energies, the observable energy flow is not due to QCD, but arises from the baryon production in the target fragmentation. In a model to explain the observed Λ polarization, a connection between the confinement of quarks and these polarization phenomena is suggested. (Auth.)
Measurement of the nucleon structure function using high energy muons
Energy Technology Data Exchange (ETDEWEB)
Meyers, P.D.
1983-12-01
We have measured the inclusive deep inelastic scattering of muons on nucleons in iron using beams of 93 and 215 GeV muons. To perform this measurement, we have built and operated the Multimuon Spectrometer (MMS) in the muon beam at Fermilab. The MMS is a magnetized iron target/spectrometer/calorimeter which provides 5.61 kg/cm/sup 2/ of target, 9% momentum resolution on scattered muons, and a direct measure of total hadronic energy with resolution sigma/sub nu/ = 1.4..sqrt..nu(GeV). In the distributed target, the average beam energies at the interaction are 88.0 and 209 GeV. Using the known form of the radiatively-corrected electromagnetic cross section, we extract the structure function F/sub 2/(x,Q/sup 2/) with a typical precision of 2% over the range 5 < Q/sup 2/ < 200 GeV/sup 2//c/sup 2/. We compare our measurements to the predictions of lowest order quantum chromodynamics (QCD) and find a best fit value of the QCD scale parameter ..lambda../sub LO/ = 230 +- 40/sup stat/ +- 80/sup syst/ MeV/c, assuming R = 0 and without applying Fermi motion corrections. Comparing the cross sections at the two beam energies, we measure R = -0.06 +- 0.06/sup stat/ +- 0.11/sup syst/. Our measurements show qualitative agreement with QCD, but quantitative comparison is hampered by phenomenological uncertainties. The experimental situation is quite good, with substantial agreement between our measurements and those of others. 86 references.
On the A dependence in the process of dilepton production by high-energy nucleons
International Nuclear Information System (INIS)
Gevorkyan, S.R.; Zhamkochyan, V.M.
1978-01-01
The process of lepton pair production in nucleon-nucleus collisions for high energies is considered. It is shown, that with due regard for the N → π → μ + μ - inelastic transitions the experimentally observed A dependence of the cross section of the NA → μ + μ - X process can be explained in the framework of the multiple scattering theory
QMD and JAM calculations for high energy nucleon-nucleus collisions
International Nuclear Information System (INIS)
Niita, Koji
2002-01-01
We describe the two simulation codes, QMD and JAM (Jet AA Microscopic Transport Model), for high energy nuclear reactions. QMD can treat the nucleus-nucleus reactions as well as nucleon-nucleus reactions based on the molecular dynamics. We have applied the QMD code intensively to nucleon-nucleus reactions and checked its validity. The cross sections obtained by the QMD are now used for evaluation of high energy nuclear data in JAERI. JAM is a hadronic cascade code including the resonance and string model for the hadron-hadron collisions at high energy up to 200 GeV. We have developed a high energy particle transport code NMTC/JAM by including the JAM code for the intra-nuclear cascade part. (author)
High energy nuclear collisions in the few GeV/nucleon region: projectile and target fragmentation
International Nuclear Information System (INIS)
Schroeder, L.S.
1980-06-01
A general review of nucleon-nucleus and nucleus-nucleus collisions for incident energies <10 GeV/nucleon is presented. The division of these interactions into peripheral and central collisions is briefly discussed. Subjects treated include the following: target and projectile fragmentation systematics, production of exotic nuclear fragments, studies of multiparticle final states, total cross section measurements, results from an experiment that indicate the production of projectile fragments with an anomalously short reaction mean free path, high-energy particle production at backward angles beyond simple N-N kinematic limits, and recent results on backward particle emission in studies with the Berkeley streamer chamber. Both the particle and nuclear physics aspects that are present are considered. A brief discussion of future trends in this energy range ends the presentation. 65 references, 37 figures
Energy Technology Data Exchange (ETDEWEB)
Jung, Chang Kee [State University of New York at Stony Brook; Douglas, Michaek [State University of New York at Stony Brook; Hobbs, John [State University of New York at Stony Brook; McGrew, Clark [State University of New York at Stony Brook; Rijssenbeek, Michael [State University of New York at Stony Brook
2013-07-29
This is the final report of the DOE grant DEFG0292ER40697 that supported the research activities of the Stony Brook High Energy Physics Group from November 15, 1991 to April 30, 2013. During the grant period, the grant supported the research of three Stony Brook particle physics research groups: The Nucleon Decay and Neutrino group, the Hadron Collider Group, and the Theory Group.
Cucinotta, Francis A.; Hajnal, Ferenc; Wilson, John W.
1990-01-01
The transport of nuclear fragmentation recoils produced by high-energy nucleons in the region of the bone-tissue interface is considered. Results for the different flux and absorbed dose for recoils produced by 1 GeV protons are presented in a bidirectional transport model. The energy deposition in marrow cavities is seen to be enhanced by recoils produced in bone. Approximate analytic formulae for absorbed dose near the interface region are also presented for a simplified range-energy model.
Results of searches for the nucleon structure displays in high energy hadron-nucleus collisions
International Nuclear Information System (INIS)
Strugalski, Z.
1984-01-01
Hadron-nucleus collision data at projectile energy from a few GeV up to about eight thousand GeV were analysed in order to find effects in which a nucleon structure manifests itself. It was found that some nucleon structure displays in incident hadron deflection in its passage through atomic nuclei and in multiple production process, at energies above about 2 GeV. The distribution of the deflection angles consists of two components, the mean free path for multiparticle production is about three times larger than the expected one. These effects may be interpreted as caused by a nucleon structure
International Nuclear Information System (INIS)
Yong Gaochan; Li Baoan; Chen Liewen
2007-01-01
Within a transport model it is shown that the neutron/proton ratio of squeezed-out nucleons perpendicular to the reaction plane, especially at high transverse momenta, in heavy-ion reactions induced by high energy neutron-rich nuclei can be a useful tool for studying the high density behavior of the nuclear symmetry energy
Extended sudden approximation model for high-energy nucleon removal reactions
Energy Technology Data Exchange (ETDEWEB)
Carstoiu, F.; Sauvan, E.; Orr, N.A. [Caen Univ., Lab. de Physique Corpusculaire, Institut des Sciences de la Matiere et du Rayonnement, IN2P3-CNRS ISMRA, 14 (France); Carstoiu, F. [IFIN-HH, Bucharest-Magurele (Romania); Bonaccorso, A. [Istituto Nazionale di Fisica Nucleare, Pisa (Italy)
2004-04-01
A model based on the sudden approximation has been developed to describe high energy single nucleon removal reactions. Within this approach, which takes as its starting point the formalism of Hansen, the nucleon-removal cross section and the full 3-dimensional momentum distributions of the core fragments including absorption, diffraction, Coulomb and nuclear-Coulomb interference amplitudes, have been calculated. The Coulomb breakup has been treated to all orders for the dipole interaction. The model has been compared to experimental data for a range of light, neutron-rich psd-shell nuclei. Good agreement was found for both the inclusive cross sections and momentum distributions. In the case of {sup 17}C, comparison is also made with the results of calculations using the transfer-to-the-continuum model. The calculated 3-dimensional momentum distributions exhibit longitudinal and transverse momentum components that are strongly coupled by the reaction for s-wave states, whilst no such effect is apparent for d-waves. Incomplete detection of transverse momenta arising from limited experimental acceptances thus leads to a narrowing of the longitudinal distributions for nuclei with significant s-wave valence neutron configurations, as confirmed by the data. Asymmetries in the longitudinal momentum distributions attributed to diffractive dissociation are also explored. (authors)
Extended sudden approximation model for high-energy nucleon removal reactions
International Nuclear Information System (INIS)
Carstoiu, F.; Sauvan, E.; Orr, N.A.; Carstoiu, F.; Bonaccorso, A.
2004-04-01
A model based on the sudden approximation has been developed to describe high energy single nucleon removal reactions. Within this approach, which takes as its starting point the formalism of Hansen, the nucleon-removal cross section and the full 3-dimensional momentum distributions of the core fragments including absorption, diffraction, Coulomb and nuclear-Coulomb interference amplitudes, have been calculated. The Coulomb breakup has been treated to all orders for the dipole interaction. The model has been compared to experimental data for a range of light, neutron-rich psd-shell nuclei. Good agreement was found for both the inclusive cross sections and momentum distributions. In the case of 17 C, comparison is also made with the results of calculations using the transfer-to-the-continuum model. The calculated 3-dimensional momentum distributions exhibit longitudinal and transverse momentum components that are strongly coupled by the reaction for s-wave states, whilst no such effect is apparent for d-waves. Incomplete detection of transverse momenta arising from limited experimental acceptances thus leads to a narrowing of the longitudinal distributions for nuclei with significant s-wave valence neutron configurations, as confirmed by the data. Asymmetries in the longitudinal momentum distributions attributed to diffractive dissociation are also explored. (authors)
Angular distributions of nucleons emitted in high energy hadron-nucleus collisions
International Nuclear Information System (INIS)
Strugalski, Z.
1983-01-01
Angular distributions of ''fast'' protons, of kinetic energy from about 20 to about 400 MeV, emitted in pion-xenon nucleus collisions at 3.5 GeV/c momentum were studied in two groups of events - when particles are produced and when particle production does not occur. The distributions are practically the same in both the groups of events and in subgroups of events with various multiplicities of emitted protons. Comparison of angular distributions of protons emitted in pion-xenon nucleus collisions at 3.5 GeV/c momentum with corresponding angular distributions of protons emitted in proton-emulsion collisions at 300-400 GeV/c momentum is performed. Results obtained allow to conclude that average value of the nucleon emission angle and the nucleon angular distributions do not depend practically on the nuclear matter layer thickness the incident hadron collided with. Fast nucleons emitted from the target nucleus seem did not interact inside the parent nucleus. Fast nucleon angular distributions do not depend on the energy of incident hadron, they are the same for pion-nucleus and for proton-nucleus collisions as well
On the nucleon effective mass role to the high energy proton spallation reactions
Energy Technology Data Exchange (ETDEWEB)
Santos, B.M., E-mail: biank_ce@if.uff.br [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, 24210-346 Niterói, RJ (Brazil); Instituto Militar de Engenharia, Praça General Tibúrcio 80, 22290-270 Rio de Janeiro, RJ (Brazil); Pinheiro, A.R.C. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil); Universidade Federal do Acre, BR 364 km 04, 69920-900 Rio Branco, AC (Brazil); Gonçalves, M. [Comissão Nacional de Energia Nuclear, Rua General Severiano 90, 22290-901 Rio de Janeiro, RJ (Brazil); Duarte, S.B. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, RJ (Brazil); Cabral, R.G. [Instituto Militar de Engenharia, Praça General Tibúrcio 80, 22290-270 Rio de Janeiro, RJ (Brazil)
2016-04-15
We explore the effect of the nucleon effective mass to the dynamic evolution of the rapid phase of proton–nucleus spallation reactions. The analysis of the relaxation time for the non-equilibrium phase is studied by variations in the effective mass parameter. We determine the final excitation energy of the hot residual nucleus at the end of cascade phase and the de-excitation of the nuclear system is carried out considering the competition of particle evaporation and fission processes. It was shown that the excitation energy depends of the hot compound residual nucleus at the end of the rapid phase on the changing effective mass. The multiplicity of particles was also analyzed in cascade and evaporation phase of the reaction. The use of nucleon effective mass during cascade phase can be considered as an effect of the many-body nuclear interactions not included explicitly in a treatment to the nucleon–nucleon interaction inside the nucleus. This procedure represents a more realistic scenario to obtain the neutron multiplicity generated in this reaction, which is a benchmark for the calculation of the neutronic in the ADS reactors.
International Nuclear Information System (INIS)
Gel'fand, E.K.; Man'ko, B.V.; Serov, A.Ya.; Sychev, B.S.
1979-01-01
A complex of programs for modelling various radiation situations at high energy proton accelerators is considered. The programs are divided into there main groups according to their purposes. The first group includes programs for preparing constants describing the processes of different particle interaction with a substanc The second group of programs calculates the complete function of particle distribution arising in shields under irradiation by high energy nucleons. Concrete radiation situations arising at high energy proton accelerators are calculated by means of the programs of the third group. A list of programs as well as their short characteristic are given
Comparative study of various methods of primary energy estimation in nucleon-nucleon interactions
International Nuclear Information System (INIS)
Goyal, D.P.; Yugindro Singh, K.; Singh, S.
1986-01-01
The various available methods for the estimation of primary energy in nucleon-nucleon interactions have been examined by using the experimental data on angular distributions of shower particles from p-N interactions at two accelerator energies, 67 and 400 GeV. Three different groups of shower particle multiplicities have been considered for interactions at both energies. It is found that the different methods give quite different estimates of primary energy. Moreover, each method is found to give different values of energy according to the choice of multiplicity groups. It is concluded that the E ch method is relatively the better method among all the methods available, and that within this method, the consideration of the group of small multiplicities gives a much better result. The method also yields plausible estimates of inelasticity in high energy nucleon-nucleon interactions. (orig.)
Structure of the neutral current coupling in high energy neutrino--nucleon interactions
International Nuclear Information System (INIS)
Merritt, F.S.
1977-01-01
The primary objective of this experiment was to determine the Lorentz structure of the neutral current coupling--that is, to determine what combination of V-A and V+A (or possibly S, P, and T) components make up the neutral coupling. The experiment used the Fermilab narrow band neutrino beam to provide separated neutrino and antineutrino fluxes, each consisting of two energy bands at approximately equal to 55 and approximately equal to 150 GeV. Deep inelastic inclusive neutrino-nucleon interactions of the form ν(anti ν) + N = μ - (μ + ) + hadrons (CC event) ν(anti ν) + N = ν(anti ν) + hadrons (NC event) were observed in an instrumented steel target-calorimeter, which measured the total energy of the hadrons produced in each event. The neutral current coupling was determined by comparing the hadron energy distributions of neutrino and antineutrino neutral current events. An analysis of the charged-current data was carried out in order to determine the background of charged-current events with unobserved muons, and to provide a normalization for the neutral current data. Various parameterizations of the CC interaction were tested, and their effects on the neutral current analysis were studied in detail. The neutral current analysis indicates that, if only vector and axial-vector components exist, then the neutral current coupling lies between V and V-A. A pure scalar coupling is excluded. The data were compared to the Weinberg--Salam theory (extended to semileptonic interactions), and are in very good agreement with its predictions. Comparison of these data to the low energy Gargamelle data indicates consistency with a scaling hypothesis
High energy pp and anti-pp elastic scattering in nucleon valence core model
International Nuclear Information System (INIS)
Islam, M.M.; Fearnley, T.
1986-01-01
Connection between the valence core model and the effective QCD models of nucleon structure is pointed out. Also, implication of recent anti-pp differential cross section measurements at 53 GeV on our previous calculations is discussed
Nucleon-nucleon correlations and the Coulomb Displacement Energy
International Nuclear Information System (INIS)
Van Neck, D.; Waroquier, M.; Heyde, K.
1997-01-01
Coulomb Displacement Energies (CDE) are accurately known for a wide range of nuclear masses. Assuming isospin independence in the nuclear Hamiltonian, the CDE can in first instance be interpreted as the Coulomb interaction energy between the density of the excess neutrons and the proton charge density in the parent nucleus. However, when using reasonable mean-field models for the proton and neutron density one underestimates the CDE by about 8% on average. This discrepancy is known as the Nolen-Schiffer anomaly, and various explanations have been put forward in the past. In this work the role of nucleon-nucleon correlations are re-examined. Calculations for the pair density functions in various nuclei are presented. Preliminary results suggest that the modifications to the mean-field pair density functions cause an enhancement of the CDE in the order of 4%, which is rather A-independent. (author)
International Nuclear Information System (INIS)
Strugalski, Z.
1982-01-01
Asymmetry in nucleon emission intensity angular distributions relatively to the hadron deflection plane and to two planes normal to it and related to it uniquely is analyzed, using appropriate experimental data on pion-xenon nucleus collisions at 3.5 GeV/c momentum. Quantative characteristics of the asymmetries found are presented in tables and on figures
High-energy electroweak neutrino-nucleon deeply virtual Compton scattering
International Nuclear Information System (INIS)
Machado, Magno V. T.
2007-01-01
In this work we estimate the differential and total cross sections for the high-energy deeply virtual Compton scattering in the weak sector. In the weak neutral sector one considers neutrino scattering off an unpolarized proton target through the exchange of Z 0 . We numerically compute the process Z*p→γp within the QCD color dipole formalism, which successfully describes the current high-energy electromagnetic DVCS experimental data. We also discuss possible applications for the weak charged sector and perform predictions for scattering on nuclear targets
The effect of including tensor forces in nucleon-nucleon interaction on three-nucleon binding energy
International Nuclear Information System (INIS)
Osman, A.; Ramadan, S.
1986-01-01
Separable two-body interactions are used in considering the three-nucleon problem. The nucleon-nucleon potentials are taken to include attraction and repulsion as well as tensor forces. The separable approximation is used in order to investigate the effect of the tensor forces. The separable expansion is introduced in the three-nucleon problem, by which the Faddeev equations are reduced to a well-behaved set of coupled integral equations. Numerical calculations are carried out for the obtained integral equations using potential functions of the Yamaguchi, Gaussian, Takabin, Mongan and Reid forms. The present calculated values of the binding energies of the 3 H and 3 He nuclei are in good agreement with the experimental values. The effect of including the tensor forces in the nucleon-nucleon interactions is found to improve the three-nucleon binding energy by about 4.490% to 8.324%. 37 refs., 2 tabs. (author)
3D parton imaging of the nucleon in high-energy p p and p A collisions
Frankfurt, L; Weiss, C
2004-01-01
We discuss several examples of how the transverse spatial distribution of partons in the nucleon, as well as multiparton correlations, can be probed by observing hard processes (dijets) in high-energy pp(pp) and pA(dA) collisions. Such studies can complement the information gained from measurements of hard exclusive processes in ep scattering. The transverse spatial distribution of partons determines the distribution over pp impact parameters of events with hard dijet production. Correlations in the transverse positions of partons can be studied in multiple dijet production. We find that the correlation cross section measured by the CDF Collaboration, sigma//e //f//f = 14.5 plus or minus 1.7//-//2//.//3**+**1**.**7 mb, can be explained by "constituent quark" type quark-gluon correlations with r //q approximately equals r//N/3, as suggested by the instanton liquid model of the QCD vacuum. Longitudinal and transverse multiparton correlations can be separated in a model-independent way by comparing multiple dije...
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
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
Spin-polarized high-energy scattering of charged leptons on nucleons
Energy Technology Data Exchange (ETDEWEB)
Burkardt, Matthias; Nowak, Wolf-Dieter; MILLER, A.
2009-01-01
The proton is a composite object with spin one-half, understood to contain highly relativistic spin one-half quarks exchanging spin-one gluons, each possibly with significant orbital angular momenta. While their fundamental interactions are well described by Quantum ChromoDynamics (QCD), our standard theory of the strong interaction, nonperturbative calculations of the internal structure of the proton based directly on QCD are beginning to provide reliable results. Most of our present knowledge of the structure of the proton is based on experimental measurements interpreted within the rich framework of QCD. An area presently attracting intense interest, both experimental and theoretical, is the relationship between the spin of the proton and the spins and orbital angular momenta of its constituents. While remarkable progress has been made, especially in the last decade, the discovery and investigation of new concepts have revealed that much more remains to be learned. This progress i
Spin-polarized high-energy scattering of charged leptons on nucleons
Energy Technology Data Exchange (ETDEWEB)
Burkardt, M. [New Mexico State Univ., Las Cruces, NM (United States). Dept. of Physics; Miller, C.A. [TRIUMF, Vancouver, BC (Canada); Nowak, W.D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2009-08-15
The proton is a composite object with spin one-half, understood to contain highly relativistic spin one-half quarks exchanging spin-one gluons, each possibly with significant orbital angular momenta. While their fundamental interactions are well described by Quantum ChromoDynamics (QCD), our standard theory of the strong interaction, nonperturbative calculations of the internal structure of the proton based directly on QCD are beginning to provide reliable results. Most of our present knowledge of the structure of the proton is based on experimental measurements interpreted within the rich framework of QCD. An area presently attracting intense interest, both experimental and theoretical, is the relationship between the spin of the proton and the spins and orbital angular momenta of its constituents. While remarkable progress has been made, especially in the last decade, the discovery and investigation of new concepts have revealed that much more remains to be learned. This progress is reviewed and an outlook for the future is offered. (orig.)
Spin-polarized high-energy scattering of charged leptons on nucleons
International Nuclear Information System (INIS)
Burkardt, M.; Nowak, W.D.
2009-08-01
The proton is a composite object with spin one-half, understood to contain highly relativistic spin one-half quarks exchanging spin-one gluons, each possibly with significant orbital angular momenta. While their fundamental interactions are well described by Quantum ChromoDynamics (QCD), our standard theory of the strong interaction, nonperturbative calculations of the internal structure of the proton based directly on QCD are beginning to provide reliable results. Most of our present knowledge of the structure of the proton is based on experimental measurements interpreted within the rich framework of QCD. An area presently attracting intense interest, both experimental and theoretical, is the relationship between the spin of the proton and the spins and orbital angular momenta of its constituents. While remarkable progress has been made, especially in the last decade, the discovery and investigation of new concepts have revealed that much more remains to be learned. This progress is reviewed and an outlook for the future is offered. (orig.)
International Nuclear Information System (INIS)
Osman, A.; Ramadan, S.
1989-01-01
Faddeev equations of bound three-nucleon system are presented as a set of integral equations. To solve them, a sutable form of the nucleon-nucleon interactions is used: with the exchange of a scalar meson, a pseudoscalar meson and a massless vector meson. Higher orders of these different meson exchanges in the nucleon-nucleon interactions have been taken into account. With these nuclear forces and nucleon-nucleon interactions, the three-nucleon binding energy is calculated by solving the Faddeev integral equations. The obtained value of the three-nucleon binding energy is 8.441 MeV. The inclusion of the higher order terms of the different meson exchange in the nuclear nucleon-nucleon interaction is found to affect the three-nucleon binding by about 3.92%. 3 figs., 16 refs
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
Chiral symmetry and nucleon structure: Low energy aspects
International Nuclear Information System (INIS)
Weise, W.
1989-01-01
The symmetries and currents of QCD at low energy and long wavelength are realized in the form of mesons, rather than quarks and gluons. In this talk I summarize the merits, but also the limits, of chiral non-linear meson theories and their soliton solutions, in descriptions of nucleon structure and the nucleon-nucleon interaction. (orig.)
Nucleon self-energy in the relativistic Brueckner theory
Energy Technology Data Exchange (ETDEWEB)
Waindzoch, T; Fuchs, C; Faessler, A [Inst. fuer Theoretische Physik, Univ. Tuebingen (Germany)
1998-06-01
The self-energy of the nucleon in nuclear matter is calculated in the relativistic Brueckner theory. We solve the Thompson equation for the two nucleon scattering in the medium using different Bonn potentials. The self-energy has a rather strong momentum dependence while the equation of state compares well with previous calculations. (orig.)
Nucleon self-energy in the relativistic Brueckner theory
International Nuclear Information System (INIS)
Waindzoch, T.; Fuchs, C.; Faessler, A.
1998-01-01
The self-energy of the nucleon in nuclear matter is calculated in the relativistic Brueckner theory. We solve the Thompson equation for the two nucleon scattering in the medium using different Bonn potentials. The self-energy has a rather strong momentum dependence while the equation of state compares well with previous calculations. (orig.)
Off-energy-shell variations of two-nucleon transition matrix and three-nucleon problem
International Nuclear Information System (INIS)
Stingl, M.; Sauer, P.U.
1975-01-01
For a schematic three-nucleon problem, approximate analytic expressions are derived for the functional derivatives of measurable three-particle quantities with respect to off-shell variations of the triplet-s two-nucleon transition matrix. Those quantities include neutron-deuteron scattering lengths, trinucleon binding energies, and the 3 He charge form-factor minimum; correlations between off-shell changes in the latter two are discussed. An indication is given how results of this kind may be to decide whether or not a given set of discrepancies between calculated and experimental three-nucleon observables can be reconciled in terms of off-shell variations of a nonretarded hermitean two-nucleon interaction. The treatment is not restricted to special classes of phase-shift equivalent potentials or phase-shift preserving transformations but instead makes use of a systematic parameterization of off-shell variations in terms of symmetric rational approximants of increasing order
Symmetry energy of nucleonic matter with tensor correlations
Hen, Or; Li, Bao-An; Guo, Wen-Jun; Weinstein, L. B.; Piasetzky, Eli
2015-02-01
The nuclear symmetry energy (Esym(ρ ) ) is a vital ingredient of our understanding of many processes, from heavy-ion collisions to neutron stars structure. While the total nuclear symmetry energy at nuclear saturation density (ρ0) is relatively well determined, its value at supranuclear densities is not. The latter can be better constrained by separately examining its kinetic and potential terms and their density dependencies. The kinetic term of the symmetry energy, Esymkin(ρ0) , equals the difference in the per-nucleon kinetic energy between pure neutron matter (PNM) and symmetric nuclear matter (SNM), often calculated using a simple Fermi gas model. However, experiments show that tensor force induced short-range correlations (SRC) between proton-neutron pairs shift nucleons to high momentum in SNM, where there are equal numbers of neutrons and protons, but have almost no effect in PNM. We present an approximate analytical expression for Esymkin(ρ0) of correlated nucleonic matter. In our model, Esymkin(ρ0) =-10 MeV, which differs significantly from +12.5 MeV for the widely-used free Fermi gas model. This result is consistent with our analysis of recent data on the free proton-to-neutron ratios measured in intermediate energy nucleus-nucleus collisions as well as with microscopic many-body calculations, and previous phenomenological extractions. We then use our calculated Esymkin(ρ ) in combination with the known total symmetry energy and its density dependence at saturation density to constrain the value and density dependence of the potential part and to extrapolate the total symmetry energy to supranuclear densities.
Low energy peripheral scaling in nucleon-nucleon scattering and uncertainty quantification
Ruiz Simo, I.; Amaro, J. E.; Ruiz Arriola, E.; Navarro Pérez, R.
2018-03-01
We analyze the peripheral structure of the nucleon-nucleon interaction for LAB energies below 350 MeV. To this end we transform the scattering matrix into the impact parameter representation by analyzing the scaled phase shifts (L + 1/2) δ JLS (p) and the scaled mixing parameters (L + 1/2)ɛ JLS (p) in terms of the impact parameter b = (L + 1/2)/p. According to the eikonal approximation, at large angular momentum L these functions should become an universal function of b, independent on L. This allows to discuss in a rather transparent way the role of statistical and systematic uncertainties in the different long range components of the two-body potential. Implications for peripheral waves obtained in chiral perturbation theory interactions to fifth order (N5LO) or from the large body of NN data considered in the SAID partial wave analysis are also drawn from comparing them with other phenomenological high-quality interactions, constructed to fit scattering data as well. We find that both N5LO and SAID peripheral waves disagree more than 5σ with the Granada-2013 statistical analysis, more than 2σ with the 6 statistically equivalent potentials fitting the Granada-2013 database and about 1σ with the historical set of 13 high-quality potentials developed since the 1993 Nijmegen analysis.
Isospin splitting of nucleon effective mass and symmetry energy in isotopic nuclear reactions
Guo, Ya-Fei; Chen, Peng-Hui; Niu, Fei; Zhang, Hong-Fei; Jin, Gen-Ming; Feng, Zhao-Qing
2017-10-01
Within an isospin and momentum dependent transport model, the dynamics of isospin particles (nucleons and light clusters) in Fermi-energy heavy-ion collisions are investigated for constraining the isospin splitting of nucleon effective mass and the symmetry energy at subsaturation densities. The impacts of the isoscalar and isovector parts of the momentum dependent interaction on the emissions of isospin particles are explored, i.e., the mass splittings of and (). The single and double neutron to proton ratios of free nucleons and light particles are thoroughly investigated in the isotopic nuclear reactions of 112Sn+112Sn and 124Sn+124Sn at incident energies of 50 and 120 MeV/nucleon, respectively. It is found that both the effective mass splitting and symmetry energy impact the kinetic energy spectra of the single ratios, in particular at the high energy tail (larger than 20 MeV). The isospin splitting of nucleon effective mass slightly impacts the double ratio spectra at the energy of 50 MeV/nucleon. A soft symmetry energy with stiffness coefficient of γ s=0.5 is constrained from the experimental data with the Fermi-energy heavy-ion collisions. Supported by Major State Basic Research Development Program in China (2014CB845405, 2015CB856903), National Natural Science Foundation of China (11722546, 11675226, 11675066, U1332207) and Youth Innovation Promotion Association of Chinese Academy of Sciences
ψ' and J/ψ suppression in high-energy nucleon-nucleus and nucleus-nucleus collisions
International Nuclear Information System (INIS)
Wong, Cheuk-Yin.
1995-01-01
The observed features of ψ' to J/ψ suppression in pA and nucleus-nucleus collisions can be explained in terms of a two-component absorption model. For the hard component of the absorption due to the interaction of the produced c bar c systems with baryons at high relative energies, the absorption cross sections are insensitive to the radii of the c bar c systems, as described by the Additive Quark Model. For the soft component due to the low energy c bar c interactions with soft particles produced by other baryon-baryon collisions, the absorption cross sections are greater for ψ' than for J/ψ, because the breakup threshold for ψ' is much smaller than for ψ
Intermediate energy nucleon-deuteron scattering theory.
Wilson, J. W.
1973-01-01
Sloan's conclusion (1969) that terms of the multiple-scattering series beyond single scattering contribute only to S- and P-wave amplitudes in an S-wave separable model is examined. A comparison of experiments with the calculation at 146 MeV shows that the conclusion is valid in nucleon-deuteron scattering applications.
Haldar, T K; Bhattacharya, D P; 10.1023/A:1024822518795
2003-01-01
Vertical muon energy spectra at sea level have been estimated from a directly measured primary cosmic-ray nucleon spectrum. The hadronic energy moments have been calculated from the CERN LEBC EHS data on the Lorentz invariant cross-section results on pp to pi /sup +or-/X and pp to K/sup +or-/X inclusive reactions and are duly corrected for A-A collisions. Finally, the sea level muon energy spectra have been calculated from the decay of conventional mesons, using standard formulation. The estimated muon spectra are found to be in good agreement with the directly measured muon spectra obtained from different experiments. (32 refs).
Nucleon-deuteron low energy parameters
International Nuclear Information System (INIS)
Zankel, H.; Mathelitsch, L.
1983-01-01
Momentum space Fadeev equations are solved for nucleon-deuteron scattering and effective range parameters are calculated. A reverse trend is found in the two spin states by 4 asub(nd) 4 asub(pd) and 2 asub(pd) 2 asub(nd) which is in agreement with a configuration space calculation, but in conflict with all existing experiments. The Coulomb contributions to the effective range are small in quartet but sizeable in doublet scattering. (Author)
International Nuclear Information System (INIS)
Xu, Chang; Li, Bao-An; Chen, Lie-Wen
2014-01-01
In this contribution, we review the most important physics presented originally in our recent publications. Some new analyses, insights and perspectives are also provided. We showed recently that the symmetry energy E sym (ρ) and its density slope L(ρ) at an arbitrary density ρ can be expressed analytically in terms of the magnitude and momentum dependence of the single-nucleon potentials using the Hugenholtz-Van Hove (HVH) theorem. These relationships provide new insights about the fundamental physics governing the density dependence of nuclear symmetry energy. Using the isospin and momentum (k) dependent MDI interaction as an example, the contribution of different terms in the single-nucleon potential to the E sym (ρ) and L(ρ) are analyzed in detail at different densities. It is shown that the behavior of E sym is mainly determined by the first-order symmetry potential U sym,1 (ρ, k) of the single-nucleon potential. The density slope L(ρ) depends not only on the first-order symmetry potential U sym,1 (ρ, k) but also on the second-order one U sym,2 (ρ, k). Both the U sym,1 (ρ, k) and U sym,2 (ρ, k) at normal density ρ 0 are constrained by the isospin- and momentum-dependent nucleon optical potential extracted from the available nucleon-nucleus scattering data. The U sym,2 (ρ, k) especially at high density and momentum affects significantly the L(ρ), but it is theoretically poorly understood and currently there is almost no experimental constraints known. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Xu, Chang [Nanjing University, Department of Physics, Nanjing (China); Li, Bao-An [Texas A and M University-Commerce, Department of Physics and Astronomy, Commerce, Texas (United States); Chen, Lie-Wen [Shanghai Jiao Tong University, Department of Physics and Astronomy and Shanghai Key Laboratory for Particle Physics and Cosmology, Shanghai (China)
2014-02-15
In this contribution, we review the most important physics presented originally in our recent publications. Some new analyses, insights and perspectives are also provided. We showed recently that the symmetry energy E{sub sym} (ρ) and its density slope L(ρ) at an arbitrary density ρ can be expressed analytically in terms of the magnitude and momentum dependence of the single-nucleon potentials using the Hugenholtz-Van Hove (HVH) theorem. These relationships provide new insights about the fundamental physics governing the density dependence of nuclear symmetry energy. Using the isospin and momentum (k) dependent MDI interaction as an example, the contribution of different terms in the single-nucleon potential to the E{sub sym} (ρ) and L(ρ) are analyzed in detail at different densities. It is shown that the behavior of E{sub sym} is mainly determined by the first-order symmetry potential U{sub sym,1}(ρ, k) of the single-nucleon potential. The density slope L(ρ) depends not only on the first-order symmetry potential U{sub sym,1}(ρ, k) but also on the second-order one U{sub sym,2}(ρ, k). Both the U{sub sym,1}(ρ, k) and U{sub sym,2}(ρ, k) at normal density ρ {sub 0} are constrained by the isospin- and momentum-dependent nucleon optical potential extracted from the available nucleon-nucleus scattering data. The U{sub sym,2}(ρ, k) especially at high density and momentum affects significantly the L(ρ), but it is theoretically poorly understood and currently there is almost no experimental constraints known. (orig.)
Potential energy surfaces for nucleon exchanging in dinuclear systems
International Nuclear Information System (INIS)
Li Jianfeng; Xu Hushan; Li Wenfei; Zuo Wei; Li Junqing; Wang Nan; Zhao Enguang
2003-01-01
The experimental measurements have provided the evidence that the suppression of fusion cross-section caused by quasi-fission is very important for the synthesis of super-heavy nuclei by heavy ion collisions. The potential energy surface due to the nucleon transfer in the collision process is the driven potential, which governs the nucleon transfer, so that governs the competition between the fusion and quasi-fission. The dinuclear system potential energy surface also gives the information about the optimum projectile-target combination, as well as the optimum excitation energy for the synthesis of super-heavy nuclei by heavy ion collisions
International Nuclear Information System (INIS)
Yakosawa, A.
1977-01-01
Results of various asymmetry measurements in nucleon-nucleon scattering with polarized beams and targets at ZGS energies are presented. A possible direct-channel resonance in the pp system is discussed. Most of the discussion above ZGS energies are aimed at future measurements
Nucleon electric dipole moments in high-scale supersymmetric models
International Nuclear Information System (INIS)
Hisano, Junji; Kobayashi, Daiki; Kuramoto, Wataru; Kuwahara, Takumi
2015-01-01
The electric dipole moments (EDMs) of electron and nucleons are promising probes of the new physics. In generic high-scale supersymmetric (SUSY) scenarios such as models based on mixture of the anomaly and gauge mediations, gluino has an additional contribution to the nucleon EDMs. In this paper, we studied the effect of the CP-violating gluon Weinberg operator induced by the gluino chromoelectric dipole moment in the high-scale SUSY scenarios, and we evaluated the nucleon and electron EDMs in the scenarios. We found that in the generic high-scale SUSY models, the nucleon EDMs may receive the sizable contribution from the Weinberg operator. Thus, it is important to compare the nucleon EDMs with the electron one in order to discriminate among the high-scale SUSY models.
Nucleon electric dipole moments in high-scale supersymmetric models
Energy Technology Data Exchange (ETDEWEB)
Hisano, Junji [Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI),Nagoya University,Nagoya 464-8602 (Japan); Department of Physics, Nagoya University,Nagoya 464-8602 (Japan); Kavli IPMU (WPI), UTIAS, University of Tokyo,Kashiwa, Chiba 277-8584 (Japan); Kobayashi, Daiki; Kuramoto, Wataru; Kuwahara, Takumi [Department of Physics, Nagoya University,Nagoya 464-8602 (Japan)
2015-11-12
The electric dipole moments (EDMs) of electron and nucleons are promising probes of the new physics. In generic high-scale supersymmetric (SUSY) scenarios such as models based on mixture of the anomaly and gauge mediations, gluino has an additional contribution to the nucleon EDMs. In this paper, we studied the effect of the CP-violating gluon Weinberg operator induced by the gluino chromoelectric dipole moment in the high-scale SUSY scenarios, and we evaluated the nucleon and electron EDMs in the scenarios. We found that in the generic high-scale SUSY models, the nucleon EDMs may receive the sizable contribution from the Weinberg operator. Thus, it is important to compare the nucleon EDMs with the electron one in order to discriminate among the high-scale SUSY models.
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
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.)
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
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 E_{γ} >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
Nucleon-nucleon optical model for energies to 3 GeV
International Nuclear Information System (INIS)
Funk, A.; Von Geramb, H.V.; University of Melbourne, VIC; Amos, K.A.
2001-01-01
Several nucleon-nucleon potentials, Paris, Nijmegen, Argonne, and those derived by quantum inversion, which describe the NN interaction for T Lab ≤ 300 MeV are extended in their range of application as NN optical models. Extensions are made in r-space using complex separable potentials definable with a wide range of form factor options including those of boundary condition models. We use the latest phase shift analyses SP00 (FA00, WI00) of Arndt et al. from 300 MeV to 3 GeV to determine these extensions. The imaginary parts of the optical model interactions account for loss of flux into direct or resonant production processes. The optical potential approach is of particular value as it permits one to visualize fusion, and subsequent fission, of nucleons when T Lab > 2 GeV. We do so by calculating the scattering wave functions to specify the energy and radial dependences of flux losses and of probability distributions. Furthermore, half-off the energy shell t-matrices are presented as they are readily deduced with this approach. Such t-matrices are required for studies of few- and many-body nuclear reactions
Theoretical interpretation of medium energy nucleon nucleus inelastic scattering
International Nuclear Information System (INIS)
Lagrange, Christian
1970-06-01
A theoretical study is made of the medium energy nucleon-nucleus inelastic scattering (direct interaction), by applying the distorted wave Born approximation such as can be deduced from the paired equation method. It is applied to the interpretation of the inelastic scattering of 12 MeV protons by 63 Cu; this leads us to make use of different sets of wave functions to describe the various states of the target nucleus. We analyze the nature of these states and the shape of the nucleon-nucleus interaction potential, and we compare the results with those obtained from other theoretical and experimental work. (author) [fr
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
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
Energy Technology Data Exchange (ETDEWEB)
Henley, E M [Washington Univ., Seattle (USA). Dept. of Physics; Wolfenstein, L [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics
1978-05-15
The low-energy scattering of nucleons by /sup 2/H, /sup 3/He and /sup 4/He is analyzed for parity nonconserving effects. The asymmetry in the total cross section of longitudinally polarized projectiles is formulated in terms of the optical theorem and a distorted-wave Born approximation. For two nucleons at low energies it is only necessary to consider l = 0 to l = 1 matrix elements of the weak nucleon-nucleon potential. The asymmetries in the scattering from nuclear targets are related to the parameters of an effective weak nucleon-nucleon potential, so that they may be used to help differentiate between various proposed theoretical potentials.
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
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.)
Energy dissipation process for 100-MeV protons and the nucleon-nucleon interactions in nuclei
International Nuclear Information System (INIS)
Cowley, A.A.; Chang, C.C.; Holmgren, H.D.; Silk, J.D.; Hendrie, D.L.; Koontz, R.W.; Roos, P.G.; Samanta, C.; Wu, J.R.
1980-01-01
Coincidence studies of two protons emitted from p+ 58 Ni at 100 MeV have been carried out. The proton spectra in coincidence with scattered protons suffering an average energy loss of 60 MeV are similar to those resulting from 60-MeV incident protons. This suggests that the initial interaction of the incident proton is with a bound nucleon and that one or both of these nucleons are emitted or initiates a cascade leading to more complex states
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
International Nuclear Information System (INIS)
McClelland, J.B.; Aas, B.; Azizi, A.
1982-01-01
A complete measurement of the polarization transfer observables has been made for the first time in the (p,p') reaction at intermediate energies. Measurements are reported for the 12 C(p,p') 12 C reaction to the 1 + , T = 0(12.71 MeV) and 1 + , T = 1(15.11 MeV) states at 500 MeV at laboratory scattering angles of 3.5 0 , 5.5 0 , 7.5 0 , and 12.0 0 . Linear combinations of these observables are shown to exhibit a very selective dependence on the isoscalar and isovector spin-dependent components of the nucleon-nucleon interaction. To the extent of the validity of the single collision approximation, these amplitudes are compared directly to the free nucleon-nucleon amplitudes at small momentum transfers
2002-01-01
The proposal concerns an extension to higher energies of previous experiments which have provided evidence for anomalously short reaction mean free paths among projectile fragments from heavy ion interactions.\\\\ \\\\ It is intended to provide information on the interaction properties of projectile fragments, mainly 3He, P, D, T as well as of scattered 4He nuclei in passive detectors exposed to beams of energies exceeding those available in previous experim factor of about 7. \\\\ \\\\ Interaction mean free paths and event topologies will be measured in a nuclear emulsion stack (LBL) of 7.5~cm~x~5~cm~x~25~cm dimensions. Decay effects will be recorded by comparing the activity of spallation residues in dense and diluted copper target assemblies (Marburg). Target fragmentation will be studied in a stack of silverchloride crystal foils (Frankfurt) of about 7~cm~x~6~cm~x~1~cm dimensions. The \\alpha beam ejected at EJ~62 will be used to provide both exposures at high intensity of 10|1|2 alphas on th and at low intensity ...
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
Energy-dependent microscopic optical potential for scattering of nucleons on light nuclei
Energy Technology Data Exchange (ETDEWEB)
Farag, M.Y.H.; Esmael, E.H. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Maridi, H.M. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Taiz University, Physics Department, Faculty of Applied Science, Taiz (Yemen)
2014-06-15
We present an energy-dependent microscopic optical model potential for elastic scattering of nucleons on light nuclei. The single-folding model is used for the real part of the optical potential (OP), while the imaginary part is derived within the high-energy approximation theory. The energy dependence of the OP is determined from the parameterization of the volume integrals those calculated from the best-fit OP that fit the experimental data of the cross sections and analyzing powers. This energy-dependent OP is successfully applied to analyze the proton elastic scattering of {sup 4,6,i8}He, {sup 6,7}Li, and {sup 9,10}Be nuclei at low and intermediate incident energies up to 200MeV/nucleon. (orig.)
Electron scattering from nucleons and deuterons at intermediate energies
International Nuclear Information System (INIS)
Burkert, V.
1985-04-01
Recent results from electron scattering of nucleons and deuterons are discussed. A tentative physics program for ELSA employing the polarized electron beams as well as the polarized nucleon and deuteron target facilities is outlined. (orig.)
Low-energy antikaon nucleon and nucleus interaction studies
Marton, Johann; Leannis Collaboration
2011-04-01
The antikaon (K-) interaction on nucleons and nuclei at low energy is neither simple nor well understood. Kaonic hydrogen is a very interesting case where the strong interaction of K- with the proton leads to an energy shift and a broadening of the 1s ground state. These two observables can be precisely studied with x-ray spectroscopy. The behavior at threshold is influenced strongly by the elusive Lambda(1405) resonance. In Europe the DAFNE electron-positron collider at Laboratori Nazionali di Frascati (LNF) provides an unique source of monoenergetic kaons emitted in the Phi meson decay. Recently the experiment SIDDHARTA on kaonic hydrogen and helium isotopes was successfully performed at LNF. A European network LEANNIS with an outreach to J-PARC in Japan was set up which is promoting the research on the antikaon interactions with nucleons and nuclei. This talk will give an overview of LEANNIS research tasks, the present status and an outlook to future perspectives. Financial support by the EU project HadronPhysics2 is gratefully acknowledged.
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
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
Mass distributions in nucleon-induced fission at intermediate energies
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).
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.
Predictions of Quantum Molecular Dynamical Model between incident energy 50 and 1000 MeV/Nucleon
Directory of Open Access Journals (Sweden)
Kumar Sanjeev
2015-01-01
Full Text Available In the present work, the Quantum Molecular Dynamical (QMD model is summarized as a useful tool for the incident energy range of 50 to 1000 MeV/nucleon in heavy-ion collisions. The model has reproduced the experimental results of various collaborations such as ALADIN, INDRA, PLASTIC BALL and FOPI upto a high level of accuracy for the phenomena like multifragmentation, collective flow as well as elliptical flow in the above prescribed energy range. The efforts are further in the direction to predict the symmetry energy in the wide incident energy range.
Effect of two-pion exchange in nucleon-nucleon scattering in high partial waves
International Nuclear Information System (INIS)
Harun ar Rashid, A.M.; Chaudhury, T.K.
1983-01-01
The work of Brown and Durso (Phys. Lett. 35B, 120 (1971)) on the soft-pion determination of the intermediate range nucleon-nucleon interaction is extended by using the most general form of the ΔNπ interaction which involves an arbitrary parameter Z. It is shown that both the annihilation channel helicity amplitude fsub(+)sup((O))(t) as well as peripheral proton-proton scattering phase shifts seem to favour Z=1/2. (author)
Energy Technology Data Exchange (ETDEWEB)
Tornow, W.; Howell, C.R.; Alohali, M.; Chen, Z.P.; Felsher, P.D.; Hanly, J.M.; Walter, R.L.; Weisel, G. (Duke Univ., Durham, NC (USA). Dept. of Physics Triangle Universities Nuclear Lab., Durham, NC (USA)); Mertens, G. (Tuebingen Univ. (Germany, F.R.). Physikalisches Inst.); Slaus, I. (Institut Rudjer Boskovic, Zagreb (Yugoslavia)); Witala, H.; Gloeckle, W. (Bochum Univ. (Germany, F.R.). Inst. fuer Theoretische Physik 2)
1991-03-28
Data for the analyzing power A{sub y}({theta}) for the elastic scattering of neutrons from deuterons have been measured at 5.0, 6.5 and 8.5 MeV to an accuracy of +-0.0035. Surprisingly large differences have been observed at these low energies between the data and rigorous Faddeev calculations using the Paris and Bonn B nucleon-nucleon potentials. The A{sub y}({theta}) data provide a stringent test for our present understanding of the on-shell and off-shell {sup 3}P{sub 0,1,2} nucleon-nucleon interactions. (orig.).
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
Energy Technology Data Exchange (ETDEWEB)
Keppel, C. [Virginia Union Univ., Richmond, VA (United States)
1994-04-01
Nucleon resonance electroproduction results from SLAC Experiment E14OX are presented. A CEBAF facility with doubled energy would enable similar high momentum transfer measurements to be made with greater accuracy. Of particular interest are the Delta P{sub 33}(1232) resonance form factor and R = {sigma}{sub L}/{sigma}{sub T}, the ratio of the longitudinal and transverse components of the cross section. A suggestion is made to study these quantities in conjunction with Bloom-Gilman duality.
Low-energy analysis of the nucleon electromagnetic form factors
International Nuclear Information System (INIS)
Kubis, Bastian.; Meissner, Ulf-G.
2001-01-01
We analyze the electromagnetic form factors of the nucleon to fourth order in relativistic baryon chiral perturbation theory. We employ the recently proposed infrared regularization scheme and show that the convergence of the chiral expansion is improved as compared to the heavy-fermion approach. We also discuss the inclusion of vector mesons and obtain an accurate description of all four-nucleon form factors for momentum transfer squared up to Q 2 ≅0.4 GeV 2
Nucleon exchange and excitation energy division in damped collisions
International Nuclear Information System (INIS)
Viola, V.E.; Planeta, R.; Kwiatkowski, K.; Zhou, S.H.; Breuer, H.
1989-01-01
In this paper we will examine both the dependence of nucleon exchange on target-projectile properties and the question of temperature equilibration and heat partition during scission. Primary emphasis will be placed on the results of a recent study of the 74 Ge + 165 Ho system, which allows us to address these two questions simultaneously. The results can thus be directly compared with the predictions of the nucleon-exchange model. (author)
Describing the nucleon electromagnetic form factors at high momentum transfers
International Nuclear Information System (INIS)
Theussl, L.; Desplanques, B.; Silvestre-Brac, B.; Varga, K.
1999-01-01
Electromagnetic form factors of the nucleon are calculated within the framework of a non-relativistic constituent-quark model. The emphasis is put on the reliability and accuracy of present day numerical methods used to solve the three-body problem. The high-q 2 behaviour of the form factors is determined by the form of the wave function at short distances and, due to the small absolute values that one deals with, an accurate solution is essential. Refs. 5, figs. 2 (author)
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
The potential energy of an infinite system of nucleons and delta resonances
International Nuclear Information System (INIS)
Goodwin, N.H.
1980-01-01
The nature and properties of the delta resonance, Δ (1236), in infinite nuclear and neutron matter are investigated. Calculations of the potential energy of a system of separate Fermi seas of nucleons and delta resonances have been performed using Jastrow lowest-order constrained variational techniques. Using the Reid soft-core nucleon-nucleon interaction and a model, consistent, energy-dependent, static one-pion- and one-rho-meson-exchange nucleon-delta potential, a significant reduction in the potential energy of the system is found at densities above nuclear matter density (0.17 fm -3 ) when deltas are present. The density at which the formation of a separate Fermi sea of deltas is favourable is estimated and the consequences for the possible formation of a pion condensate and the properties of neutron star matter are discussed. (author)
The nucleon-nucleus scattering at intermediate energies
International Nuclear Information System (INIS)
Auger, J.-P.
1976-01-01
The Glauber model has the merit to connect directly the nucleon-nucleus elastic differential cross section with the nucleon-nucleon amplitude and nuclear densities. The general agreement between the 1 GeV proton elastic scattering differential cross sections calculated without adjustable parameter and the experimental data (from He 4 to Pb 208 ) is rather satisfactory up to 2. - 2.5 fm -1 momentum transfer. Although the 1 GeV proton elastic scattering experiments constitute at present one of the best method in determining neutron densities, it seems that self-consistent calculations bring the best knowledge of these densities. The model independent analysis performed with electron and proton scattering experiments show that the difference between neutron and proton r.m.s. radius cannot be determined better than 25-30% for Pb 208 [fr
High-Precision Determination of the Pion-Nucleon σ Term from Roy-Steiner Equations
Hoferichter, Martin; Ruiz de Elvira, Jacobo; Kubis, Bastian; Meißner, Ulf-G.
2015-08-01
We present a determination of the pion-nucleon (π N ) σ term σπ N based on the Cheng-Dashen low-energy theorem (LET), taking advantage of the recent high-precision data from pionic atoms to pin down the π N scattering lengths as well as of constraints from analyticity, unitarity, and crossing symmetry in the form of Roy-Steiner equations to perform the extrapolation to the Cheng-Dashen point in a reliable manner. With isospin-violating corrections included both in the scattering lengths and the LET, we obtain σπ N=(59.1 ±1.9 ±3.0 ) MeV =(59.1 ±3.5 ) MeV , where the first error refers to uncertainties in the π N amplitude and the second to the LET. Consequences for the scalar nucleon couplings relevant for the direct detection of dark matter are discussed.
Constructing Nucleon Operators on a Lattice for Form Factors with High Momentum Transfer
Energy Technology Data Exchange (ETDEWEB)
Syritsyn, Sergey [Stony Brook Univ., NY (United States); Gambhir, Arjun S. [College of William and Mary, Williamsburg, VA (United States); Musch, Bernhard U. [Univ. of Regensburg (Germany); Orginos, Konstantinos [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2017-05-01
We present preliminary results of computing nucleon form factor at high momentum transfer using the 'boosted' or 'momentum' smearing. We use gauge configurations generated with N f = 2 + 1dynamical Wilson-clover fermions and study the connected as well as disconnected contributions to the nucleon form factors. Our initial results indicate that boosted smearing helps to improve the signal for nucleon correlators at high momentum. However, we also find evidence for large excited state contributions, which will likely require variational analysis to isolate the boosted nucleon ground state.
Nucleon-nucleon scattering data
International Nuclear Information System (INIS)
Bystricky, J.; Lehar, F.
1981-01-01
The present review contains a compilation of p-p, n-n, n-p and p-n elastic scattering data, total cross sections for elastic and inelastic nucleon-nucleon processes as well as the slope parameters and the ratios of the real to the imaginary part of the forward scattering amplitude measured at all energies. The data are given in detailed tables with comments on each measurement. Summary tables, nucleon-nucleon kinematics formulae, transformation tables for kinematics, a detailed list of references and an author index complete the paper. (orig.)
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
Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
Czech Academy of Sciences Publication Activity Database
Ageev, E.; Alexakhin, V.; Alexandrov, Y.; Alexeev, G.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.; Bytchkov, V.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.; Costa, S.; Crespo, M.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S. S.; De Masi, R.; Dedek, N.; Denisov, O.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.; Dolgopolov, A.; Donskov, S.; Dorofeev, V.; Doshita, N.; Duic, V.; Dünnweber, W.; Ehlers, J.; Eversheim, P.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger jr., M.; Fischer, H.; Franz, J.; Friedrich, J.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.; Grajek, O.; Grasso, A.; Grube, B.; Grünemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.; Ilgner, C.; Ioukaev, A.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Khomutov, N.; Kisselev, Y.; Klein, F.; Koblitz, S.; Koivuniemi, J.; Kolosov, V.; Komissarov, E.; Kondo, K.; Königsmann, K.; Konoplyannikov, A.; Konorov, I.; Konstantinov, V.; Korentchenko, A.; Korzenev, A.; Kotzinian, A.; Koutchinski, N.; Kowalik, K.; Kravchuk, N.; Krivokhizhin, G.; Kroumchtein, Z.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.; Lamanna, M.; Le Goff, J.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.; Manuilov, I.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.; Medved, K.; Meyer, W.; Mielech, A.; Mikhailov, Y.; Moinester, M.; Nähle, O.; Nassalski, J.; Neliba, S.; Neyret, D.; Nikolaenko, V.; Nozdrin, A.; Obraztsov, V.; Olshevsky, A.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.; Peshekhonov, D.; Peshekhonov, V.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.; Popov, A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.; Rondio, E.; Sadovski, A.; Saller, E.; Samoylenko, V.; Sandacz, A.; Sans, M.; Sapozhnikov, M.; Savin, I.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.; Shishkin, A.; Siebert, H.; Sinha, L.; Sissakian, A.; Skachkova, A.; Slunecka, M.; Smirnov, G.; Sozzi, F.; Sugonyaev, V.; Srnka, Aleš; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.; Tassarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.; Toeda, T.; Tretyak, V.; Trousov, S.; Varanda, M.; Virius, M.; Vlassov, N.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.
2006-01-01
Roč. 633, č. 1 (2006), s. 25-32 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : nucleon * spin * gluon * polarization * asymmetry * deep inelastic scattering Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.043, year: 2006
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
The nucleon as a test case to calculate vector-isovector form factors at low energies
Leupold, Stefan
2018-01-01
Extending a recent suggestion for hyperon form factors to the nucleon case, dispersion theory is used to relate the low-energy vector-isovector form factors of the nucleon to the pion vector form factor. The additionally required input, i.e. the pion-nucleon scattering amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the nucleons and optionally the Delta baryons. Two methods to include pion rescattering are compared: a) solving the Muskhelishvili-Omnès (MO) equation and b) using an N/D approach. It turns out that the results differ strongly from each other. Furthermore the results are compared to a fully dispersive calculation of the (subthreshold) pion-nucleon amplitudes based on Roy-Steiner (RS) equations. In full agreement with the findings from the hyperon sector it turns out that the inclusion of Delta baryons is not an option but a necessity to obtain reasonable results. The magnetic isovector form factor depends strongly on a low-energy constant of the NLO Lagrangian. If it is adjusted such that the corresponding magnetic radius is reproduced, then the results for the corresponding pion-nucleon scattering amplitude (based on the MO equation) agree very well with the RS results. Also in the electric sector the Delta degrees of freedom are needed to obtain the correct order of magnitude for the isovector charge and the corresponding electric radius. Yet quantitative agreement is not achieved. If the subtraction constant that appears in the solution of the MO equation is not taken from nucleon+Delta chiral perturbation theory but adjusted such that the electric radius is reproduced, then one obtains also in this sector a pion-nucleon scattering amplitude that agrees well with the RS results.
The nucleon as a test case to calculate vector-isovector form factors at low energies
Energy Technology Data Exchange (ETDEWEB)
Leupold, Stefan [Uppsala Universitet, Institutionen foer Fysik och Astronomi, Uppsala (Sweden)
2018-01-15
Extending a recent suggestion for hyperon form factors to the nucleon case, dispersion theory is used to relate the low-energy vector-isovector form factors of the nucleon to the pion vector form factor. The additionally required input, i.e. the pion-nucleon scattering amplitudes are determined from relativistic next-to-leading-order (NLO) baryon chiral perturbation theory including the nucleons and optionally the Delta baryons. Two methods to include pion rescattering are compared: a) solving the Muskhelishvili-Omnes (MO) equation and b) using an N/D approach. It turns out that the results differ strongly from each other. Furthermore the results are compared to a fully dispersive calculation of the (subthreshold) pion-nucleon amplitudes based on Roy-Steiner (RS) equations. In full agreement with the findings from the hyperon sector it turns out that the inclusion of Delta baryons is not an option but a necessity to obtain reasonable results. The magnetic isovector form factor depends strongly on a low-energy constant of the NLO Lagrangian. If it is adjusted such that the corresponding magnetic radius is reproduced, then the results for the corresponding pion-nucleon scattering amplitude (based on the MO equation) agree very well with the RS results. Also in the electric sector the Delta degrees of freedom are needed to obtain the correct order of magnitude for the isovector charge and the corresponding electric radius. Yet quantitative agreement is not achieved. If the subtraction constant that appears in the solution of the MO equation is not taken from nucleon+Delta chiral perturbation theory but adjusted such that the electric radius is reproduced, then one obtains also in this sector a pion-nucleon scattering amplitude that agrees well with the RS results. (orig.)
Nucleon currents and frictional forces between highly excited nuclei
International Nuclear Information System (INIS)
Barranco, M.; Pi, M.; Vinas, X.; Ngo, C.; Tomasi, E.
1983-01-01
A finite temperature Thomas-Fermi method has been used to study the nucleon transfer between two hot slabs of symmetric nuclear matter. Special attention has been paid to temperature effects neglected in earlier calculations. As a result, closed and ready-to-use formulas for the exchange and transfer nucleon flux at zero relative momentum are given as a function of the temperature T. We also present a rather detailed discussion of thermal properties of the semi-infinite slabs
Experimental studies and microscopic analysis of the elastic scattering of low energy nucleons
International Nuclear Information System (INIS)
Tarrats-Saugnac, Annie.
1982-05-01
Data on the elastic scattering of low energy nucleons (between 20 and 40 MeV) by nuclei distributed throughout the entire mass table are examined in the framework of a microscopic approach. Two major problems occur at these low energies which do not occur at higher energies: the Pauli principle limits the interaction possibilities of projectiles with bound nucleons in the nucleus; it is not possible to neglect the antisymmetrization between projectiles and nucleon targets resulting in the addition of a nonlocal term to the potential. A quadratic moment approximation is used. As regards the inhibition of reactions inside the nucleus by the Pauli principle, an effective interaction with a relatively simple analytical form and easy to use for systematic analyses was determined [fr
High energy lepton-nucleon scattering
International Nuclear Information System (INIS)
Sciulli, F.
1982-01-01
The author summarizes the general expressions expected for neutrino scattering, and the formula for the electromagnetic process which is involved for minor scattering. He discusses the complications of quark binding and the historical development of fits from deep inelastic data. He also evaluates the signifigance of the results gained from the data, concluding his discussion by asking basic questions about the tests of the quark model and suggesting that there is still much to be learned about inelastic scattering, that more precision is necessary. The author is hopeful that the work now being conducted on the CFRR data will help solve some of the discrepancy
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
International Nuclear Information System (INIS)
Xu Chang; Li Baoan; Chen Liewen; Ko, Che Ming
2011-01-01
Using the Hugenholtz-Van Hove theorem, we derive general expressions for the quadratic and quartic symmetry energies in terms of the isoscalar and isovector parts of single-nucleon potentials in isospin asymmetric nuclear matter. These expressions are useful for gaining deeper insights into the microscopic origins of the uncertainties in our knowledge on nuclear symmetry energies especially at supra-saturation densities. As examples, the formalism is applied to two model single-nucleon potentials that are widely used in transport model simulations of heavy-ion reactions.
Li, Pengcheng; Wang, Yongjia; Li, Qingfeng; Guo, Chenchen; Zhang, Hongfei
2018-04-01
With the newly updated version of the ultrarelativistic quantum molecular dynamics (UrQMD) model, a systematic investigation of the effects of in-medium nucleon-nucleon (NN ) elastic cross section on the collective flow and the stopping observables in 197Au+197Au collisions at beam energies from 40 to 150 MeV/nucleon is performed. Simulations with the medium correction factors F =σNN in -medium/σNN free=0.2 ,0.3 ,0.5 and the one obtained with the FU3FP1 parametrization which depends on both the density and the momentum are compared to the FOPI and INDRA experimental data. It is found that, to best fit the experimental data of the slope of the directed flow and the elliptic flow at midrapidity as well as the nuclear stopping, the correction factors of F =0.2 and 0.5 are required for reactions at beam energies of 40 and 150 MeV/nucleon, respectively. Whereas calculations with the FU3FP1 parametrization can simultaneously reproduce these experimental data reasonably well. And, the observed increasing nuclear stopping with increasing beam energy in experimental data can also be reproduced by using the FU3FP1 parametrization, whereas the calculated stopping power in Au + Au collisions with beam energies from 40 to 150 MeV /nucleon almost remains constant when taking F equal to a fixed value.
Energy Technology Data Exchange (ETDEWEB)
Sebille, F.; Bonilla, C. [SUBATECH, Universite de Nantes, CNRS/IN2P3, 44 - Nantes (France); Blideanu, V.; Lecolley, J.F. [Laboratoire de Physique Corpusculaire, ENSICAEN, Universite de Caen, IN2P3-CNRS, 14 - Caen (France)
2004-06-01
A microscopic investigation of nucleon-induced reactions is addressed within the DYWAN model, which is based on the projection methods of out of equilibrium statistical physics and on the mathematical theory of wavelets. Due to a strongly compressed representation of the fermionic wave-functions, the numerical simulations of the nucleon transport in target are therefore able to preserve the quantum nature of the colliding system, as well as a least biased many-body information needed to keep track of the cluster formation. A special attention is devoted to the fingerprints of the phase space topology induced by the fluctuations of the self-consistent mean-field. Comparisons be ween theoretical results and experimental data point out that ETDHF type approaches are well suited to describe reaction mechanisms in the Fermi energy domain. The observed sensitivity to physical effects shows that the nucleon-induced reactions provide a valuable probe of the nuclear interaction in this range of energy. (authors)
Pre-equilibrium emission of nucleons from reactions induced by medium-energy heavy ions
International Nuclear Information System (INIS)
Korolija, M.; Holuh, E.; Cindro, N.; Hilscher, D.
1984-01-01
Recent data on fast-nucleon emission in heavy-ion-induced reactions are analysed successfully in terms of pre-equilibrium models; it is shown that the relevant parameters of those models preserve the physical meaning they have in light-ion-induced reactions. The initial exciton number obtained from a Griffin-plot analysis and the initial number of degrees of freedom, which is the relevant parameter of the modified HMB model, appear to be approximately equal for a given reaction at a given energy. It is inferred that, for heavy-ion reactions, the determination of such a parameter is substantially dominated by the centre-of-mass energy per nucleon above the Coulomb barrier, in contrast with the results of nucleon-induced reactions
Transverse energy production in 208Pb+Pb collisions at 158 GeV per nucleon
International Nuclear Information System (INIS)
Alber, T.; Appelshaeuser, H.; Baechler, J.; Bartke, J.; Bialkowska, H.; Bieser, F.; Bloomer, M.A.; Blyth, C.O.; Bock, R.; Bormann, C.; Brady, F.P.; Brockmann, R.; Buncic, P.; Caines, H.L.; Cebra, D.; Chan, P.; Cooper, G.E.; Cramer, J.G.; Cramer, P.B.; Csato, P.; Derado, I.; Dunn, J.; Eckardt, V.; Eckhardt, F.; Euler, S.; Ferguson, M.I.; Fischer, H.G.; Fodor, Z.; Foka, P.; Freund, P.; Fuchs, M.; Gal, J.; Gazdzicki, M.; Gladysz, E.; Grebieszkow, J.; Guenther, J.; Harris, J.W.; Heck, W.; Hegyi, S.; Hill, L.A.; Huang, I.; Howe, M.A.; Igo, G.; Irmscher, D.; Jacobs, P.; Jones, P.G.; Kadija, K.; Kecskemeti, J.; Kowalski, M.; Kuehmichel, A.; Lasiuk, B.; Margetis, S.; Mitchell, J.W.; Mock, A.; Nelson, J.M.; Odyniec, G.; Palinkas, J.; Palla, G.; Panagiotou, A.D.; Petridis, A.; Piper, A.; Poskanzer, A.M.; Prindle, D.J.; Puehlhofer, F.; Rauch, W.; Renfordt, R.; Retyk, W.; Ritter, H.G.; Roehrich, D.; Rudolph, H.; Runge, K.; Sandoval, A.; Sann, H.; Schaefer, E.; Schmitz, N.; Schoenfelder, S.; Seyboth, P.; Seyerlein, J.; Sikler, F.; Skrzypczak, E.; Stock, R.; Stroebele, H.; Szentpetery, I.; Sziklai, J.; Toy, M.; Trainor, T.A.; Trentalange, S.; Vassiliou, M.; Vesztergombi, G.; Vranic, D.; Wenig, S.; Whitten, C.; Wienold, T.; Wood, L.; Zimanyi, J.; Zhu, X.; Zybert, R.
1995-01-01
Measurements of the forward and the transverse energy in 158 GeV per nucleon 208 Pb+Pb collisions are presented. A total transverse energy of about 1 TeV is created in central collisions. An energy density of about 3GeV/fm 3 is estimated for near head-on collisions. Only statistical fluctuations are seen in the ratio of electromagnetic to hadronic transverse energy. copyright 1995 The American Physical Society
Measurement of the transverse energy spectrum in proton-nucleon collisions
International Nuclear Information System (INIS)
Bettoni, D.
1988-01-01
The author describes a measurement of the transverse energy spectrum in proton-nucleon interactions carried out at the CERN SPS using the HELIOS spectrometer. The measurement is of particular interest in that it is performed in a rapidity region away from central rapidity, where experimental data is scarce. In this rapidity region very interesting physics is anticipated and the measurement of the proton-nucleon collisions is essential as a basis to understand the more complicated proton-nucleus and nucleus-nucleus interactions. Both these topics are part of the experimental program of HELIOS. The measurement was done using a deuterium target enclosed in an iron tube. The contribution to the transverse energy spectrum from the p-Fe events is discriminated against by reconstructing the primary interaction vertex using drift chamber information. The measured spectrum is corrected via Monte Carlo to deconvolute the effect of reinteractions. High spatial resolution and multi-track resolving power are achieved with the use of a cool gas, such that the electron characteristic energy is close to the thermal limit: this implies a small diffusion coefficient and a consequently good positional accuracy. Of vital importance are the low value of the drift velocity, the fast, differentiating electronics and a careful shaping of the electric field configuration to improve the isochrony of the drift collection. The author reports on the design and tests of drift chamber prototypes built along the above lines, with which a spatial accuracy of 0.06 mm and a double track resolution of 0.6 mm were measured. He also describes the final drift chamber system and its operation in HELIOS
International Nuclear Information System (INIS)
Wilcke, W.W.; Schroeder, W.U.; Huizenga, J.R.; Birkelund, J.R.; Randrup, J.
1980-01-01
Although considerable progress has been achieved in the understanding of strongly damped reactions at energies several MeV/u above the Coulomb barrier, some important experimental results are not yet clearly understood. Among these is the degree of correlation between the nucleon exchange and the large energy losses observed. Experimental evidence suggesting nucleon exchange as described by a one-body model to be the major component of the dissipation mechanism is discussed. It is concluded that the previously unexplained bombarding energy dependence between energy loss and fragment charge dispersion can be understood on the basis of a nucleon exchange model, provided the Pauli exclusion principle is taken into account. No necessity is seen to invoke further energy dissipation mechanisms. 7 figures
Assessment of Coulomb shifts in nucleon scattering resonances on light nuclei at low energies
International Nuclear Information System (INIS)
Takibaev, N.Zh.; Uzakova, Zh.; Abdanova, L.
2003-01-01
The assessments of the Coulomb forces contribution to position and width of the resonances at nucleons scattering on light nuclei within low energy field are given. In particular the shifts of resonances in amplitudes arising in the processes protons scattering on light nuclei relatively neutrons scattering resonance characteristics on these nuclei are considered
International Nuclear Information System (INIS)
Filippov, G.F.; Lopez Trujillo, A.; Rybkin, I.Yu.
1993-01-01
The matrix elements of the potential energy operator (which includes central, spin-orbit and tensor components) are calculated between the generating invariants of the cluster basis describing α + d and t+h configurations of the six-nucleon system. (author). 12 refs
Energy Technology Data Exchange (ETDEWEB)
Farag, M.Y.H.; Esmael, E.H. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Maridi, H.M. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Taiz University, Physics Department, Faculty of Applied Science, Taiz (Yemen)
2012-11-15
The proton elastic scattering data on some light exotic nuclei, namely, {sup 6,} {sup 8}He, {sup 9,} {sup 11}Li, and {sup 10,} {sup 11,} {sup 12}Be, at energies below than 100MeV/nucleon are analyzed using the single folding optical model. The real, imaginary, and spin-orbit parts of the optical potential (OP) are constructed only from the folded potentials and their derivatives using M3Y effective nucleon-nucleon interaction. These OP parts, their renormalization factors and their volume integrals are studied. The surface and spin-orbit potentials are important to fit the experimental data. Three model densities for halo nuclei are used and the sensitivity of the cross-sections to these densities is tested. The imaginary OP within high-energy approximation is used and compared with the single folding OP. This OP with few and limited fitting parameters, which have systematic behavior with incident energy, successfully describes the proton elastic scattering data with exotic nuclei. (orig.)
Medium energy nucleon-nucleus scattering theory by semi-classical distorted wave approximation
Energy Technology Data Exchange (ETDEWEB)
Ogata, Kazuyuki [Kyushu Univ., Fukuoka (Japan)
1998-07-01
The semiclassical distorted wave model (SCDW) is one of the quantum mechanical models for nucleon inelastic and charge exchange scattering at intermediate energies. SCDW can reproduce the double differential inclusive cross sections for multi-step direct processes quite well in the angular and outgoing energy regions where the model is expected to work. But the model hitherto assumed on-the-energy-shell (on-shell) nucleon-nucleon scattering in the nucleus, neglecting the difference in the distorting potentials for the incoming and the outgoing particles and also the Q-value in the case of (p,n) reactions. There had also been a problem in the treatment of the exchange of colliding nucleons. Now we modify the model to overcome those problems and put SCDW on sounder theoretical foundations. The modification results in slight reduction (increase) of double differential cross sections at forward (backward) angles. We also examine the effect of the in-medium modification of N-N cross sections in SCDW and find it small. A remedy of the disagreement at very small and large angles in terms of the Wigner transform of the single particle density matrix is also discussed. This improvement gives very promising results. (author)
Nuclear energy density functional from chiral pion-nucleon dynamics revisited
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...
Wang, Ting-Ting; Ma, Yu-Gang; Zhang, Chun-Jian; Zhang, Zheng-Qiao
2018-03-01
The proton-proton momentum correlation function from different rapidity regions is systematically investigated for the Au + Au collisions at different impact parameters and different energies from 400 A MeV to 1500 A MeV in the framework of the isospin-dependent quantum molecular dynamics model complemented by the Lednický-Lyuboshitz analytical method. In particular, the in-medium nucleon-nucleon cross-section dependence of the correlation function is brought into focus, while the impact parameter and energy dependence of the momentum correlation function are also explored. The sizes of the emission source are extracted by fitting the momentum correlation functions using the Gaussian source method. We find that the in-medium nucleon-nucleon cross section obviously influences the proton-proton momentum correlation function, which is from the whole-rapidity or projectile or target rapidity region at smaller impact parameters, but there is no effect on the mid-rapidity proton-proton momentum correlation function, which indicates that the emission mechanism differs between projectile or target rapidity and mid-rapidity protons.
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.
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.
Nucleon-nucleon theory and phenomenology
International Nuclear Information System (INIS)
Signell, P.
1981-03-01
This project involves five inter-related subprojects: (1) derivation of the intermediate range nucleon-nucleon interaction using a new method that utilizes much shorter and simpler analytic continuation through the unphysical region that lies between the πN and ππ physical regions of the N anti N → ππ amplitude (with significantly improved accuracy for the nucleon-nucleon interaction); (2) construction of a short range phenomenological potential that, with the theoretical part mentioned above, gives a precise fit to the nucleon-nucleon data and is parameterized for easy use in nucleon calculations; (3) phase shift analyses of the world data below 400 MeV, especially the large amount of very precise data below 20 MeV and the new data near 55 MeV that have never been analyzed properly; (4) the introduction of a K-matrix formulation of the Optimal Polynomial Expansion in order to accelerate convergence of the partial wave series at LAMPF energies; and (5) setting up of a cooperatively evaluated permanent nucleon-nucleon data bank in the 0-1200 MeV range that can be used by all nucleon-nucleon reseachers
International Nuclear Information System (INIS)
Guiasu, I.
1978-01-01
The goals of this work are: a) to examine and turn to account in the study of γ-proton elastic scattering the possibility of using a dispersion representation assumed for the amplitude set Asub(i), free of singularities and kinematic zeroes. This is achieved through a direct calculation of the effective unpolarized differential section of the Compton effect on the proton, at various scattering angles in an energy range of 0 β which agrees with current experimental data. c) to establish a law regarding low ω 5 order energies for the helicity amplitudes and for the unpolarized differential effective section of the process γ + p → γ' + p'. We believe this law to be necessary on one hand for a more accurate determination of the α, β variables out of existent experiments and, on the other hand, for the opportunity to define within the Compton effect on the nucleon new structure constants of the nucleon such as the quadrupolar electromagnetic polarizabilities. By fitting the formula of the unpolarized differential effective section in order ω 5 to the experimental data we obtained modified values of α, β, but still in accordance with the order α > β. d) to establish an inequality based upon the analyticity properties of the Compton invariant amplitudes between expressions that include measurable physical variables, static properties of the nucleon and integrals on the effective differential section for the process γ + p → γ' + p'. (author)
Microscopic theory for nucleon-nucleus optical potential in intermediate energies
International Nuclear Information System (INIS)
He Guozhu; Cai Chonghai
1984-01-01
Based on the scattering theory of KMT and FGH we calculate the nucleon-nucleus optical potentials of 4 He, 16 O and 40 Ca from the Paris N-N potential given by M. Lacombe et al. The real part Vsub(R)(r) of our optential has the form of Woods-Saxon when the kinetic energy E of the incident nucleon is low. The depth of Vsub(R)(r) will decrease as E increases, and it turns into positive in the interior of nucleus when E approx.= 300 MeV. The repulsive effect in the interior of nucleus increases rapidly as E increases even more, butthere always exists some attractive effect at the surface of nucleus. Therefore, Vsub(R)(r) has generally the wine-bottle bottom shape. We also calculate the quatity Jv/N = (4π/N)∫sub(0)sub(infinity)Vsub(R)(r)r 2 dr. Our results are basically in acordance with those of M.Jaminon et al's relativistic Hatree calculation as well as the experimental results. In this work we also calculate the imaginary part of optical potential and its variation with the kinetic energy of the incident nucleon
Low-energy kaon-nucleon/nuclei interaction studies at DAΦNE by AMADEUS
Directory of Open Access Journals (Sweden)
Tucaković Ivana
2015-01-01
Full Text Available The AMADEUS experiment deals with the investigation of the low-energy kaon-nuclei hadronic interaction at the DAΦNE collider at LNF-INFN, fundamental to respond to longstanding open questions in the non-perturbative QCD in the strangeness sector. One of the most interesting aspects is to understand how hadron masses and interactions change in the nuclear environment. The antikaon-nucleon potential is investigated searching for signals from possible bound kaonic clusters, which would imply a strongly attractive antikaon-nucleon potential. AMADEUS step 0 consists in the analysis of 2004/2005 KLOE data, exploring K− absorptions in H, 4He, 9Be and 12C present in setup materials. The status of the various preliminary analyses is presented, together with future perspectives.
Radiative capture of nucleons at astrophysical energies with single-particle states
International Nuclear Information System (INIS)
Huang, J.T.; Bertulani, C.A.; Guimaraes, V.
2010-01-01
Radiative capture of nucleons at energies of astrophysical interest is one of the most important processes for nucleosynthesis. The nucleon capture can occur either by a compound nucleus reaction or by a direct process. The compound reaction cross sections are usually very small, especially for light nuclei. The direct capture proceeds either via the formation of a single-particle resonance or a non-resonant capture process. In this work we calculate radiative capture cross sections and astrophysical S-factors for nuclei in the mass region A<20 using single-particle states. We carefully discuss the parameter fitting procedure adopted in the simplified two-body treatment of the capture process. Then we produce a detailed list of cases for which the model works well. Useful quantities, such as spectroscopic factors and asymptotic normalization coefficients, are obtained and compared to published data.
Systematics of intermediate-energy single-nucleon removal cross sections
Tostevin, J. A.; Gade, A.
2014-11-01
There is now a large and increasing body of experimental data and theoretical analyses for reactions that remove a single nucleon from an intermediate-energy beam of neutron- or proton-rich nuclei. In each such measurement, one obtains the inclusive cross section for the population of all bound final states of the mass A -1 reaction residue. These data, from different regions of the nuclear chart, and that involve weakly and strongly bound nucleons, are compared with theoretical expectations. These calculations include an approximate treatment of the reaction dynamics and shell-model descriptions of the projectile initial state, the bound final states of the residues, and the single-particle strengths computed from their overlap functions. The results are discussed in the light of recent data, more exclusive tests of the eikonal dynamical description, and calculations that take input from more microscopic nuclear structure models.
The nucleon-antinucleon interaction at low energies
International Nuclear Information System (INIS)
Alvear, C.
1977-08-01
A theoretical analysis is made of recent low energy data relative to scattering process p sup(-)d → p + pions from 300 to 600 Mev/c laboratory incident momentum, with the purpose of obtaining information about resonances in the pure iso-spin system p sup(-)n (I = 1). The single and double term of the multiple scattering series are evaluated using a formalism based on Glauber theory and Feynman rules. Then, the differential cross section with respect to the invariant mass of the produced pions is obtained. The theoretical results are used to analyse the available data, which are then shown to be consistent with a non resonant behavior of the p sup(-)n system. (Author) [pt
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
International Nuclear Information System (INIS)
Tornow, W.; Witala, H.; Kievsky, A.
1998-01-01
The 4 P J waves in nucleon-deuteron scattering were analyzed using proton-deuteron and neutron-deuteron data at E N =3 MeV. New sets of nucleon-nucleon 3 P j phase shifts were obtained that may lead to a better understanding of the long-standing A y (θ) puzzle in nucleon-deuteron elastic scattering. However, these sets of 3 P j phase shifts are quite different from the ones determined from both global phase-shift analyses of nucleon-nucleon data and nucleon-nucleon potential models. copyright 1998 The American Physical Society
International Nuclear Information System (INIS)
Besliu, Calin; Jipa, Alexandru; Iliescu, Bogdan; Felea, Daniel
2002-01-01
Some new aspects on the multifragmentation processes in nucleus-nucleus and nucleon-nucleus collisions at high energies are discussed in this work. Experimental data obtained in international collaborations (for example, MULTI Collaboration with KEK Tsukuba (Japan) and SKM 200 Collaboration with JINR Dubna (Russia)) are used to discuss new mechanisms in the target nucleus fragmentation. Correlations with stopping power, participant region size and energy density are included. Comparisons of the experimental results with the predictions of a phenomenological geometric model of intermediate mass fragment multiplicity, caloric curves and angular distributions are also presented. These results are used for global description of the multifragmentation processes in nucleon-nucleus and nucleus-nucleus collisions at relativistic energies. The size of the participant region and the average intermediate mass fragments multiplicity are taken into consideration using the free space probability. A few correlations between the deposited energy in the participant region and stability state of the intermediate mass fragments are presented in this work. The importance of the collision geometry in the multifragmentation processes is stressed. The results suggest different time moments for the incident nucleus fragmentation and for the target nucleus fragmentation. The associated entropies are distinct. (authors)
Three-nucleon scattering by using chiral perturbation theory potential
International Nuclear Information System (INIS)
Kamata, Hiroyuki
2003-01-01
Three-nucleon scattering problems are studied by using two-nucleon and three-nucleon potentials derived from chiral perturbation theory. The three-nucleon term is shown to appear in the effective potential of the rank of next-to-next-to-leading order (NNLO). New three-nucleon forces are taken into consideration in addition to the conventional Fujita-Miyazawa (FM) type three-nucleon potential. Two-nucleon potential of the chiral perturbation theory is as precise as the conventional ones in low energy region. The FM type three-nucleon force which explains Sagara discrepancy in high energy region is introduced automatically. Concerning the Ay puzzle, the results seems to behave as if the puzzle has been solved at the level of NLO, but at the NNLO (without three-nucleon force) level the result is similar to the cases of conventional potential indicating the need of three-nucleon force. In contrast to the FM type three-nucleon force, five free parameters exist in the new D and E type three-nucleon forces introduced by the NNLO, but they are reduced to two independent parameters by antisymmetrization, which are found to be sensitive to the coupling energy of tritons and to the nd scattering length (spin doublet state). Parameters determined from them cannot give satisfactory answer to the A y puzzle. It seems, however, too hasty to conclude that A y puzzle cannot be solved by the chiral perturbation theory. (S. Funahashi)
Spin observables in nucleon-nucleus scattering
International Nuclear Information System (INIS)
Moss, J.M.
1982-01-01
The curse of inelastic nucleon scattering and charge exchange has always been the enormous complexity of the nucleon-nucleon (N-N) interaction. This complexity, however, can also be viewed as the ultimate promise of nucleons as probes of nuclear structure. Given an adequate theoretical basis, inelastic nucleon scattering is capable of providing information not obtainable with other probes. Recently a revolution of experimental technique has taken place that makes it desirable to re-examine the question of what physics is ultimately obtainable from inelastic nucleon scattering. It is now feasible to perform complete polarization transfer (PT) experiments for inelastic proton scattering with high efficiency and excellent energy resolution. Programs to measure PT obsevables are underway at several laboratories, and results are beginning to appear. Objectives of this presentation are to examine how such experiments are done, and what physics is presently obtained and may ultimately be learned from them
Extracting the σ-term from low-energy pion-nucleon scattering
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.
Investigations of Few-Nucleon System Dynamics in Medium Energy Domain
Ciepał, I.; Kłos, B.; Kistryn, St.; Stephan, E.; Biegun, A.; Bodek, K.; Deltuva, A.; Epelbaum, E.; Eslami-Kalantari, M.; Fonseca, A. C.; Golak, J.; Jha, V.; Kalantar-Nayestanaki, N.; Kamada, H.; Khatri, G.; Kirillov, Da.; Kirillov, Di.; Kliczewski, St.; Kozela, A.; Kravcikova, M.; Machner, H.; Magiera, A.; Martinska, G.; Messchendorp, J.; Nogga, A.; Parol, W.; Ramazani-Moghaddam-Arani, A.; Roy, B. J.; Sakai, H.; Sekiguchi, K.; Sitnik, I.; Siudak, R.; Skibiński, R.; Sworst, R.; Urban, J.; Witała, H.; Wrońska, A.; Zejma, J.
2013-08-01
Precise and large set of cross sections, vector A x , A y and tensor A xx , A xy , A yy analyzing powers for the 1 H( d, pp) n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which model the three-nucleon (3N) system dynamics. The calculations are based on different two-nucleon (2N) potentials which can be combined with models of the three-nucleon force (3NF) and other pieces of the dynamics can also be included like the Coulomb interaction and relativistic effects. The cross sections data reveal seizable 3NF and Coulomb force influence. In case of analyzing powers very low sensitivity to the effects was found and the data are well describe by 2N models only. At 130 MeV for A xy serious disagreements appear when 3NF models are included into calculations.
Investigations of Few-Nucleon System Dynamics in Medium Energy Domain
International Nuclear Information System (INIS)
Ciepał, I.; Kistryn, St.; Biegun, A.; Bodek, K.; Golak, J.; Khatri, G.; Magiera, A.; Parol, W.; Skibiński, R.; Sworst, R.; Witała, H.; Wrońska, A.; Zejma, J.; Kłos, B.; Stephan, E.; Kozela, A.; Kliczewski, St.; Siudak, R.; Eslami-Kalantari, M.; Ramazani-Moghaddam-Arani, A.; Kalantar-Nayestanaki, N.; Messchendorp, J.; Machner, H.; Nogga, A.; Epelbaum, E.; Deltuva, A.; Fonseca, A. C.; Kamada, H.; Jha, V.; Kirillov, Da.; Kirillov, Di.; Sitnik, I.; Kravcikova, M.; Martinska, G.; Urban, J.; Roy, B.J.; Sakai, H.; Sekiguchi, K.
2013-01-01
Precise and large set of cross sections, vector A x , A y and tensor A xx , A xy , A yy analyzing powers for the 1 H(d, pp)n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which model the three-nucleon (3N) system dynamics. The calculations are based on different two-nucleon (2N) potentials which can be combined with models of the three-nucleon force (3NF) and other pieces of the dynamics can also be included like the Coulomb interaction and relativistic effects. The cross sections data reveal seizable 3NF and Coulomb force influence. In case of analyzing powers very low sensitivity to the effects was found and the data are well describe by 2N models only. At 130 MeV for A xy serious disagreements appear when 3NF models are included into calculations. (author)
High resolution study of nucleonic cosmic rays with Z >= 34
International Nuclear Information System (INIS)
Fowler, P.H.; Alexander, C.; Clapham, V.M.; Henshaw, D.L.; O'Ceallaigh, C.; O'Sullivan, D.; Thompson, A.
1976-01-01
Preliminary results of the analysis of large area lexan polycarbonate and nuclear emulsion sandwich stacks flown from Sioux Falls between 1971 and 1974 are given. The total exposure was approximately 120 m 2 days at approximately 3.8 g cm -2 atmospheric depth and 284 tracks of nuclei with Z >= 34 have been found to date, of which 97 have Z >= 65. The charge distribution features a platinum peak, a marked actinide gap and a high uranium group flux, but no example of a super heavy nucleus was observed. The energy spectrum of nuclei with Z >= 65 is 'normal' confirming our earlier results. (orig.) [de
International Nuclear Information System (INIS)
Oertzen, W. von; Voit, H.; Imanishi, B.
1988-10-01
This report contains a review article considering the evolution of direct mechanisms with incident energy in heavy ion reactions and two theoretical articles concerning two-center effects in transfer reactions between heavy ions and the nucleon promotion in heavy ion reactions. See hints under the relevant topics. (HSI)
Calculation of the nucleon structure function from the nucleon wave function
Hussar, Paul E.
1993-01-01
Harmonic oscillator wave functions have played an historically important role in our understanding of the structure of the nucleon, most notably by providing insight into the mass spectra of the low-lying states. High energy scattering experiments are known to give us a picture of the nucleon wave function at high-momentum transfer and in a frame in which the nucleon is traveling fast. A simple model that crosses the twin bridges of momentum scale and Lorentz frame that separate the pictures of the nucleon wave function provided by the deep inelastic scattering data and by the oscillator model is presented.
Nucleon exchange and heat partition in 74Ge + 165Ho collision at energy 8.5 MeV/A
International Nuclear Information System (INIS)
Planeta, R.
1990-01-01
This paper reports that one of the distinctive features of damped heavy-ion reactions is the rapid conversion of relative kinetic energy into heat during the lifetime of the dinuclear system formed in the collision. Of particular interest in this regard are the questions: how heat, or excitation energy, is partitioned between the reaction partners; how heat partition depends on nucleon transfer. Damped collisions at energies near or just above the barrier have been generally interpreted in terms of transport models which account for energy dissipation in terms of nucleon exchange between the projectile-like (PLF) and target-like fragments. Thus, in this context statistical nucleon exchange is the mechanism for heating of the system. Transport model calculation have met considerable success in accounting for the major features of damped collisions, for example, energy dissipation and angular distributions. Nonetheless, many important uncertainties remain
A unified treatment of high energy interactions
International Nuclear Information System (INIS)
Drescher, H.J.; Werner, K.; Ostapchenko, S.; Centre National de la Recherche Scientifique, 44 - Nantes
1999-01-01
It is well known that high energy interactions as different as electron-positron annihilation, deep inelastic lepton-nucleon scattering, proton-proton interactions, and nucleus-nucleus collisions have many features in common. Based upon this observation, a model for all these interactions is constructed which relies on the fundamental hypothesis that the behavior of high energy interactions is universal. (author)
International Nuclear Information System (INIS)
Meyer, J.
1988-01-01
The 1988 progress report of the High Energy Nuclear Physics laboratory (Polytechnic School, France), is presented. The Laboratory research program is focused on the fundamental physics of interactions, on the new techniques for the acceleration of charged particles and on the nuclei double beta decay. The experiments are performed on the following topics: the measurement of the π 0 inclusive production and the photons production in very high energy nuclei-nuclei interactions and the nucleon stability. Concerning the experiments under construction, a new detector for LEP, the study and simulation of the hadronic showers in a calorimeter and the H1 experiment (HERA), are described. The future research programs and the published papers are listed [fr
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
The phenomenon of nucleon emission at high angular momentum states of fused compound systems
Rajasekaran, T R; Santhosh-Kumar, S
2003-01-01
Nucleon emission from high spin fused compound systems is analyzed in the framework of the statistical theory of hot rotating (STHR) nuclei. This is an elaborate version of our earlier work and we present our results for sup 1 sup 5 sup 6 Er, sup 1 sup 6 sup 6 Er, sup 1 sup 6 sup 8 Yb and sup 1 sup 8 sup 8 Hg. We predict an increase in neutron emission for sup 1 sup 6 sup 6 Er due to the abrupt decrease in neutron separation energy around I approx 55h. Since the drop in the separation energy is closely associated with the structural changes in the rotating nuclei, relative increase in neutron emission probability around certain values of angular momentum may be construed as evidence for the shape transition. A similar effect is predicted for sup 1 sup 6 sup 8 Yb around I approx 55h. We also extend the microscopic cranked Nilsson method (CNM) to hot nuclear systems and compare the results with that of the STHR method. The two methods yield different results for triaxially deformed nuclei although for biaxial d...
Three-nucleon problem with phase equivalent potentials
International Nuclear Information System (INIS)
Pushkash, O.M.; Shapoval, D.V.; Simenog, I.V.
1991-01-01
The effect of the t-matrix off-shell variations with nonlocal phase equivalent N-N potentials on the three-nucleon parameters is studied. The variations, which lower or increase the tritium binding energy, are revealed. We show that under certain conditions, the three-nucleon low-energy observables are almost insensitive to the high energy behaviour of the negative parts of the scattering phase shifts. The inverse problem method is applied to reconstruct simple S-wave potentials which to provide a unified description of the two-nucleon and low-energy three-nucleon data. 22 refs.; 6 figs. (author)
Double polarized neutron-proton scattering and nucleon-nucleon tensor force: An alternative analysis
International Nuclear Information System (INIS)
Tornow, W.; Gould, C.R.; Haase, D.G.; Walston, J.R.; Raichle, B.W.
2002-01-01
Previous neutron-proton total cross-section difference measurements Δσ L and Δσ T between E n =7.43 and 17.1 MeV have been analyzed in a new way that reduces experimental systematic uncertainties. The results obtained for the 3 S 1 - 3 D 1 mixing parameter ε 1 are very similar to the published values, substantiating the previous conclusion that the nucleon-nucleon tensor force at low energies is stronger than predicted by the Nijmegen partial-wave analysis and, therefore, by all the recent high-precision nucleon-nucleon potential models as well
International Nuclear Information System (INIS)
Kazarnovskij, M.V.; Matushko, G.K.; Matushko, V.L.; Par'ev, Eh.Ya.; Serezhnikov, S.V.
1981-01-01
The problem on propagation of the internuclear cascade initiated by nucleons of 0.1-1 GeV energy in accelerator schielding is solved approximately in the analytical form. Analytical expressions for the function of spatial, angular and energy distribution of the flux density of nucleons with the energy above 20 MeV and some functionals from it are obtained. The results of the calculations obtained by the developed methods are compared with calculations obtained by the method of direct simulation. It is shown that at the atomic mass of shielding material [ru
Development of global medium-energy nucleon-nucleus optical model potentials
International Nuclear Information System (INIS)
Madland, D.G.; Sierk, A.J.
1997-01-01
The authors report on the development of new global optical model potentials for nucleon-nucleus scattering at medium energies. Using both Schroedinger and Dirac scattering formalisms, the goal is to construct a physically realistic optical potential describing nucleon-nucleus elastic scattering observables for a projectile energy range of (perhaps) 20 meV to (perhaps) 2 GeV and a target mass range of 16 to 209, excluding regions of strong nuclear deformation. They use a phenomenological approach guided by conclusions from recent microscopic studies. The experimental database consists largely of proton-nucleus elastic differential cross sections, analyzing powers, spin-rotation functions, and total reaction cross sections, and neutron-nucleus total cross sections. They will use this database in a nonlinear least-squares adjustment of optical model parameters in both relativistic equivalent Schroedinger (including relativistic kinematics) and Dirac (second-order reduction) formalisms. Isospin will be introduced through the standard Lane model and a relativistic generalization of that model
Progress in the development of global medium-energy nucleon-nucleus optical model potentials
International Nuclear Information System (INIS)
Madland, D.G.
1997-01-01
Two existing global medium-energy nucleon-nucleus phenomenological optical model potentials are described and compared with experiment and with each other. The first of these employs a Dirac approach (second-order reduction) that is global in projectile energy and projectile isospin and applies to the target nucleus 208 Pb. The second of these employs a relativistic equivalent to the Schroedinger equation (including relativistic kinematics) that is global in projectile energy, projectile isospin, and target (Z,A). Finally, current work is described and the influence of the nuclear bound state problem (treated in relativistic mean field theory) on the Dirac scattering problem is mentioned. Spherical target nuclei are treated in the present work and strongly-collective target nuclei (rotational and vibrational) requiring coupled-channels approaches will be treated in a future paper. (author)
International Nuclear Information System (INIS)
Jiang Weizhou; Li Baoan; Chen Liewen
2007-01-01
The mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter are investigated using the nucleon optical potential obtained within the relativistic impulse approximation with the empirical nucleon-nucleon scattering amplitudes and the nuclear densities obtained in the relativistic mean-field model. It is found that the isospin-splitting of nucleon mean free paths, sensitive to the imaginary part of the symmetry potential, changes its sign at certain high kinetic energy. The in-medium nucleon-nucleon cross sections are analytically and numerically demonstrated to be essentially independent of the isospin asymmetry of the medium and increase linearly with density in the high-energy region where the relativistic impulse approximation is applicable
Experiments on very high energy heavy ions
International Nuclear Information System (INIS)
Willis, W.J.
1981-01-01
In this paper I describe experimental techniques which could be used to investigate central collision of very high energy heavy ions. For my purposes, the energy range is defined by the number of pions produced, Nsub(π) >> 100, and consequently Nsub(π) >> Nsub(nucleon). In this regime we may expect that new phenomena will appear. (orig.)
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)
Norbury, John W.
1992-01-01
Single nucleon removal in relativistic and intermediate energy nucleus-nucleus collisions is studied using a generalization of Weizsacker-Williams theory that treats each electromagnetic multipole separately. Calculations are presented for electric dipole and quadrupole excitations and incorporate a realistic minimum impact parameter, Coulomb recoil corrections, and the uncertainties in the input photonuclear data. Discrepancies are discussed. The maximum quadrupole effect to be observed in future experiments is estimated and also an analysis of the charge dependence of the electromagnetic cross sections down to energies as low as 100 MeV/nucleon is made.
QCD inequalities for the nucleon mass and the free energy of baryonic matter.
Cohen, Thomas D
2003-07-18
The positivity of the integrand of certain Euclidean space functional integrals for two flavor QCD with degenerate quark masses implies that the free energy per unit volume for QCD with a baryon chemical potential mu(B) (and zero isospin chemical potential) is greater than the free energy with an isospin chemical potential mu(I)=(2 mu(B)/N(c)) (and zero baryon chemical potential). The same result applies to QCD with any number of heavy flavors in addition to the two light flavors so long as the chemical potential is understood as applying to the light quark contributions to the baryon number. This relation implies a bound on the nucleon mass: there exists a particle X in QCD (presumably the pion) such that M(N)> or =(N(c) m(X)/2 I(X)) where m(X) is the mass of the particle and I(X) is its isospin.
Fundamentals and applications of heavy ion collisions below 10 MeV/ nucleon energies
Prasad, R
2018-01-01
An up-to-date text, covering the concept of incomplete fusion (ICF) in heavy ion (HI) interactions at energies below 10 MeV/nucleon. Important concepts including the exciton model, the Harp Miller and Berne model, Hybrid model, Sum rule model, Hot spot model and promptly emitted particles model are covered in depth. It studies the ICF and PE-emission in heavy ion reactions at low energies using off-beam and in-beam experimental techniques. Theories of complete fusion (CF) of heavy ions based on Compound Nucleus (CN) mechanism of statistical nuclear reactions, details of the Computer code PACE4 based on CN mechanism, pre-equilibrium (PE) emission, modeling of (ICF) and their limits of application are discussed in detail.
Energy Technology Data Exchange (ETDEWEB)
Chatrchyan, Serguei [Yerevan Physics Inst. (Armenia); et al.
2011-08-01
Jet production in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV was studied with the CMS detector at the LHC, using a data sample corresponding to an integrated luminosity of 6.7 inverse microbarns. Jets are reconstructed using the energy deposited in the CMS calorimeters and studied as a function of collision centrality. With increasing collision centrality, a striking imbalance in dijet transverse momentum is observed, consistent with jet quenching. The observed effect extends from the lower cut-off used in this study (jet transverse momentum = 120 GeV/c) up to the statistical limit of the available data sample (jet transverse momentum approximately 210 GeV/c). Correlations of charged particle tracks with jets indicate that the momentum imbalance is accompanied by a softening of the fragmentation pattern of the second most energetic, away-side jet. The dijet momentum balance is recovered when integrating low transverse momentum particles distributed over a wide angular range relative to the direction of the away-side jet.
International Nuclear Information System (INIS)
Han Yinlu; Liang Haiying; Guo Hairui; Shen Qingbiao; Xu Yongli
2010-01-01
A set of new global phenomenological optical model potential parameters for the actinide region with incident nucleon energies from 1 keV up to 300 MeV is obtained. They are based on a smooth, unique functional form for the energy dependence of the potential depths and on physically constrained geometry parameters. The available experimental data including the neutron total cross sections, nonelastic cross sections, elastic scattering cross sections, elastic scattering angular distributions, and proton reaction cross sections and elastic scattering angular distributions of 232 Th and 238 U are used. The new nucleon global optical model potential parameters obtained are analyzed and used to analyze the experimental data of nucleon-actinide reactions. It is found that the present form of the global optical model potential could reproduce both the neutron and the proton experimental data.
High energy elastic hadron scattering
International Nuclear Information System (INIS)
Fearnly, T.A.
1986-04-01
The paper deals with the WA7 experiment at the CERN super proton synchrotron (SPS). The elastic differential cross sections of pion-proton, kaon-proton, antiproton-proton, and proton-proton at lower SPS energies over a wide range of momentum transfer were measured. Some theoretical models in the light of the experimental results are reviewed, and a comprehensive impact parameter analysis of antiproton-proton elastic scattering over a wide energy range is presented. A nucleon valence core model for high energy proton-proton and antiproton-proton elastic scattering is described
Alpha-particle breakup at incident energies of 20 and 40 MeV/nucleon
International Nuclear Information System (INIS)
Wu, J.R.; Chang, C.C.; Holmgren, H.D.; Koontz, R.W.
1979-01-01
The breakup of alpha particles at incident energies of 20 and 40 MeV/nucleon on 27 Al, 58 Ni, 90 Zr, and 209 Bi has been studied. It was found that the breakup cross section decreases rapidly with increasing angles and increases with increasing target mass and incident energy. The total breakup yield, summed over all charged fragments, is approx.15--35% of the alpha-particle total reaction cross section, and has an approximate A/sup 1/3/ dependence. The ratios of breakup yields among different fragments are approximately p:d:t: 3 He approx. = 13:3:1:2, and are roughly independent of the incident energy and the target nucleus. These features suggest that the alpha-particle fragmentation is a peripheral process and is dominated by the properties of the incident projectile. A simple plane-wave alpha-particle breakup model gives a rather good description to the experimental data. In addition to the breakup deuteron peak at half of the beam energy, a second peak at quarter of the beam energy (or the same energy as the breakup proton peak) is observed. This peak might be due to a two-step breakup-pickup process
International Nuclear Information System (INIS)
Bleser, Ed
1992-01-01
On April 24, Brookhaven's Alternating Gradient Synchrotron (AGS) started to deliver gold ions at 11.4 GeV per nucleon (2,000 GeV per ion) to experimenters who were delighted not only to receive the world's highest energy gold beam but also to receive it on schedule
Su, Jun; Zhu, Long; Guo, Chenchen
2018-05-01
Background: Special attention has been paid to study the shell effect and odd-even staggering (OES) in the nuclear spallation. Purpose: In this paper, we investigate the influence of the nuclear level density on the OES in the 56Fe+p spallations at energies from 300 to 1500 MeV/nucleon. Method: The isospin-dependent quantum molecular dynamics (IQMD) model is applied to produce the highly excited and equilibrium remnants, which is then de-excited using the statistical model gemini. The excitation energy of the heaviest hot fragments is applied to match the IQMD model with the gemini model. In the gemini model, the statistical description of the evaporation are based on the Hauser-Feshbach formalism, in which level density prescriptions are applied. Results: By investigating the OES of the excited pre-fragments, it is found that the OES originates at the end of the decay process when the excitation energy is close to the nucleon-emission threshold energy, i.e., the smaller value of the neutron separation energy and proton separation energy. The strong influence of level density on the OES is noticed. Two types of the nuclear level densities, the discrepancy of which is only about 7% near the nucleon emission threshold energy, are used in the model. However, the calculated values of the OES differ by the factor of 3 for the relevant nuclei. Conclusions: It is suggested that, although the particle-separation energies play a key role in determining the OES, the level density at excitation energy lower than the particle-separation energies should be taken into consideration
High Transverse Momentum Hadron Production in 400-GeV/c and 800-GeV/c Proton - Nucleon Collisions
Energy Technology Data Exchange (ETDEWEB)
Jaffe, David Edward [SUNY, Stony Brook
1987-08-01
Results of high transverse momentum hadron production in 400 Gev/c proton-proton and proton-deuteron and 800 Gev /c proton-proton collisions are presented in this dissertation. The transverse momentum range of the data was from 5.2 to 9.0 Gev/c for the 400 Gev/c collisions and from 3.6 to 11.0 Gev /c for the 800 Gev /c collisions; the data were centered around the proton-nucleon center-of-momentum production angle of 90°. Single pion invariant cross sections and particle ratios were measured at both energies and the unlike-sign dihadron correlation function was measured at the higher energy. The results are compared to previous experiments and the Lund model.
Polarized lepton-nucleon scattering
International Nuclear Information System (INIS)
Hughes, E.
1994-01-01
The author provides a summary of the proposed and published statistical (systematic) uncertainties from the world experiments on nucleon spin structure function integrals. By the time these programs are complete, there will be a vast resource of data on nucleon spin structure functions. Each program has quite different experimental approaches regarding the beams, targets, and spectrometers thus ensuring systematically independent tests of the spin structure function measurements. Since the field of spin structure function measurements began, there has been a result appearing approximately every five years. With advances in polarized target technology and high polarization in virtually all of the lepton beams, results are now coming out each year; this is a true signature of the growth in the field. Hopefully, the experiments will provide a consistent picture of nucleon spin structure at their completion. In summary, there are still many open questions regarding the internal spin structure of the nucleon. Tests of QCD via the investigation of the Bjorken sum rule is a prime motivator for the field, and will continue with the next round of precision experiments. The question of the origin of spin is still a fundamental problem. Researchers hope is that high-energy probes using spin will shed light on this intriguing mystery, in addition to characterizing the spin structure of the nucleon
Polarized lepton-nucleon scattering
Energy Technology Data Exchange (ETDEWEB)
Hughes, E. [Stanford Univ., CA (United States)
1994-12-01
The author provides a summary of the proposed and published statistical (systematic) uncertainties from the world experiments on nucleon spin structure function integrals. By the time these programs are complete, there will be a vast resource of data on nucleon spin structure functions. Each program has quite different experimental approaches regarding the beams, targets, and spectrometers thus ensuring systematically independent tests of the spin structure function measurements. Since the field of spin structure function measurements began, there has been a result appearing approximately every five years. With advances in polarized target technology and high polarization in virtually all of the lepton beams, results are now coming out each year; this is a true signature of the growth in the field. Hopefully, the experiments will provide a consistent picture of nucleon spin structure at their completion. In summary, there are still many open questions regarding the internal spin structure of the nucleon. Tests of QCD via the investigation of the Bjorken sum rule is a prime motivator for the field, and will continue with the next round of precision experiments. The question of the origin of spin is still a fundamental problem. Researchers hope is that high-energy probes using spin will shed light on this intriguing mystery, in addition to characterizing the spin structure of the nucleon.
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
Axial structure of the nucleon
Energy Technology Data Exchange (ETDEWEB)
Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner
2002-01-01
We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.
Excitation of Nucleon Resonances
International Nuclear Information System (INIS)
Burkert, Volker D.
2001-01-01
I discuss developments in the area of nucleon resonance excitation, both necessary and feasible, that would put our understanding of nucleon structure in the regime of strong QCD on a qualitatively new level. They involve the collection of high quality data in various channels, a more rigorous approach in the search for ''missing'' resonances, an effort to compute some critical quantities in nucleon resonance excitations from first principles, i.e. QCD, and a proposal focused to obtain an understanding of a fundamental quantity in nucleon structure
Nuclear energy density functional from chiral pion-nucleon dynamics revisited
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.
Model of homogeneous nucleus. Total and inelastic cross sections of nucleon-nucleus scattering
International Nuclear Information System (INIS)
Ponomarev, L.A.; Smorodinskaya, N.Ya.
1985-01-01
It is shown that the nucleon-nuckleus scattering amplitude at high energy can be easily calculated by generalization of the nucleon-nucleon scattering amplitude and satisfies a simple factorization relation. As distinct from the Glauber model, the suggested approach makes no use of the nucleonic structure of the nucleus and the hadron-nucleus scattering amplitude is not expressed in terms of hadron-nucleon scattering amplitudes. The energy dependence of total and inelastic cross sections is successfully described for a number of nuclei
On light cluster production in nucleon induced reactions at intermediate energy
International Nuclear Information System (INIS)
Lacroix, D.; Blideanu, V.; Durand, D.
2004-09-01
A dynamical model dedicated to nucleon induced reaction between 30-150 MeV is presented. It considers different stages of the reaction: the approaching phase, the in-medium nucleon-nucleon collisions, the cluster formation and the secondary de-excitation process. The notions of influence area and phase-space exploration during the reaction are introduced. The importance of the geometry of the reaction and of the conservation laws are underlined. The model is able to globally reproduce the absolute cross sections for the emission of neutron and light charged particles for proton and neutron induced reactions on heavy and intermediate mass targets ( 56 Fe and 208 Pb). (authors)
Study of the Nuclear Transparency in $\\alpha$ + A Reactions at Energies $\\geq$ 12 GeV/nucleon
2002-01-01
The question about transparency is crucial for heavy ion reaction studies. If the transparency is low at 10-15 GeV per nucleon then very large baryon densities can be achieved in this energy range, maybe enough to produce quark-gluon plasma in U+U collisions. We propose to measure, event by event, pseudo-rapidity and multiplicity distributions of singly charged relativistic particles (@b~$>$~0.7) globally and in selected regions of rapidity as well as multiplicities of recoiling protons (30-400~Me charged nuclear fragments. These studies will explore general features of @a+A reactions at energies @$>$~12~GeV/nucleon. The main goal of the experiment is to measure the transparency of nuclear matter in this energy range. The detector will be nuclear emulsion.
International Nuclear Information System (INIS)
Tornow, T.; Tornow, W.
1999-01-01
It Is shown that the 3 P j neutron-proton (proton-proton) phase shifts cannot be determined to less than ± 100 % (± 20 %) uncertainty at low energies (∼ 10 MeV), even if high-accuracy nucleon-nucleon data were to become available for currently inaccessible observables. For a more accurate determination, appropriate theoretical constraints have to be invoked, but their accuracy can be judged only from the comparison of rigorous three-nucleon continuum calculations with particular three-nucleon observables. (author)
Energy Technology Data Exchange (ETDEWEB)
Rogozmski, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1952-07-01
The celerity curves, pulse and wavelength of De Broglie for a nucleon (proton or neutron) have been calculated and traced accordingly to its kinetic energy. (M.B.) [French] Les courbes de vitesses, d mpulsion et de longueur d nde de Broglie d n nucleon (proton ou neutron) ont ete calcule et trace en fonction de son energie cinetique. (M.B.)
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
Electromagnetic interactions of nucleons and nuclei at low energy and momentum transfer
International Nuclear Information System (INIS)
Arenhoevel, H.
1994-01-01
In these lectures I concentrate on the manifestation of subnuclear degrees of freedom in terms of meson and isobar degrees of freedom in electromagnetic processes where their presence usually is described in terms of so-called exchange or interaction currents. In Section 2 I first discuss the general properties of the electromagnetic interaction, the gauge conditions and low-energy theorems which follow from gauge invariance, the charge and current density operators for a non-relativistic system of nucleons and the Siegert theorem. In Section 3 I sketch the basic ideas and construction methods for the exchange current operators as effective operators and in Section 4 the model of nuclear isobar configurations introducing explicitly isobar degrees of freedom into the nuclear wave function. The general features of one- and two-photon processes are discussed in Section 5. First the expressions for the cross sections of photoabsorption and electron scattering are reviewed. As a specific but important example, I then discuss the two-body break-up of the deuteron since it permits the cleanest analysis and provides one of the best evidences for the presence of subnuclear degrees of freedom due to its simple two-body structure within the classical nuclear physics framework. This is a unique situation because in more complex nuclei the analysis is often hampered by presently still unavoidable approximations of the many-body problem. I furthermore discuss the role of meson exchange currents in the photonuclear TRK sum rule, in particular, I carefully analyse what determines the enhancement. This section ends with a brief discussion of elastic photon scattering with special emphasis on the low-energy theorem for the scattering amplitude and the sum rule relations for the low-energy parameters. (orig.)
Nucleus-nucleus interaction constants at energies of 0.1-1.0 GeV/nucleon
International Nuclear Information System (INIS)
Dudkin, V.E.; P'yanov, I.I.; Stepnov, V.D.
1979-01-01
A method for calculating nucleus-nuclear reactions being a further development of the cascade model is proposed. The nucleus-nucleus interaction is represented as a superposition of a series of synchronous cascades initiated by nucleous and α-clusters getting into the nuclei overlapping region. Determination of an interaction partner and calculation of an elementary nucleon and α-cluster collision act are carried out using the same method as for calculation of the nucleon-nuclear cascade. Inelastic channels are not considered. The cross section values of cascade particle interaction, as well as of free particle interaction are given from the published literature. The experiment for verification of the calculation method is carried out. An emulsion chamber of the 0.3 l volume has been exposed at the 35 km height in the vicinity of the 64 deg nothern latitude during 8.5 hr. 223 disintegrations of nuclear emulsion by cosmic radiation nuclei at the 0.1-1.0 GeV/nucleon energy and the >2 charge are investigated. 147 interactions on photoemulsion light nuclei are singled out from these disintegrations. The average multiplicity of all the charged pions is 0.22+-0.05 for light and 0.44+-0.09 for heavy photoemulsion nuclei. The calculation is carried out for nitrogen nuclei interaction at the 0.35 GeV/nucleon energy. Parametric analysis of the calculation method has shown that the clusterization coefficients and the nuclear parameter effect secondary particle multiplicity (SPM) and weakly influence on their energy and angular distributions. The nuclear parameter change from 1.1 to 1.6 F decreases average SPM in different energy ranges down to 25-40%. The comparison of the calculation data with the experimental one obtained in the given paper and other ones, shows satisfactory agreement both for differential and average characteristics of secondary charged particles
Recent Progresses in Ab-Initio Studies of Low-Energy Few-Nucleon Reactions of Astrophysical Interest
Marcucci, Laura E.
2017-03-01
We review the most recent theoretical studies of nuclear reactions of astrophysical interest involving few-nucleon systems. In particular, we focus on the radiative capture of protons by deuterons in the energy range of interest for Big Bang Nucleosynthesis. Related to this, we will discuss also the most recent calculation of tritium β -decay. Two frameworks will be considered, the conventional and the chiral effective field theory approach.
International Nuclear Information System (INIS)
Scott, D.K.
1978-03-01
Some initial experiments in the intermediate energy region between 10 and 200 MeV/nucleon, which is largely unexplored and poorly understood is considered as regards some initial experiments in this energy region. Included are the emission of complex fragments, localization in heavy ion reactions, coincidence experiments between light and heavy fragments, and the emission of light particles in heavy ion collisions. Some initial results in the region between 20 and 100 MeV/nucleon are presented. 41 references
Nucleon form factors at high q2 within constituent quark models
International Nuclear Information System (INIS)
Desplanques, B.; Silvestre-Brac, B.; Cano, F.; Noguera, S.; Gonzalez, P.; .
2000-01-01
The nucleon form factors are calculated using a non-relativistic description in terms of constituent quarks. The emphasis is put on present numerical methods used to solve the three-body problem in order to reliably predict the expected asymptotic behavior of form factors. Nucleon wave functions obtained in the hyperspherical formalism or employing Faddeev equations have been considered. While a q -8 behavior is expected at high q for a quark-quark force behaving like 1/r at short distances, it is found that the hyper central approximation in the hyperspherical formalism (K = 0) leads to a q -7 behavior. An infinite set of waves would be required to get the correct behavior. Solutions of the Faddeev equations lead to the q -8 behavior. The coefficient of the corresponding term, however, depends on the number of partial waves retained in the Faddeev amplitude. The convergence to the asymptotic behavior has also been studied. Approximate expressions characterizing this one have been derived. From the comparison with the most complete Faddeev calculation, a validity range is inferred for restricted calculations. Refs. 46 (author)
International Nuclear Information System (INIS)
Guiasu, I.
1978-01-01
The elastic γ-nucleon scattering represents an indirect powerful method for the nucleon structure investigation. Some theoretical aspects of this problem are treated in the presented thesis. After a general introduction into the subject and a short review of the up-to-date literature, the first chapter contains kinematics and dynamical preliminaries of reaction γ+N→γ+N. In chapter II, the low energy theorems are discussed and extended up to six power in the photon laboratory energies, ω; the six structure dependent constants which appear in the differential cross section in this order are defined and computed, and an extraction for the proton electromagnetic polarizabilities α,β from the experimental data is performed. A new dispersive analysis of the γ+N→γ+N process at photon laboratory energies lower than 450 Mev is introduced and used for numerical calculation in chapter III; some improvements are obtained in the comparison with the experimental data, with respect to other previous calculations. In the last chapter, two different sum rules for the difference (α-β) are established and numerically computed - these theoretical predictions agree with the values extracted from experience; based on the analyticity properties of the invariant amplitudes, an inequality is written down connecting an integral over the differential cross section of the process and the static properties of the nucleon (mass, charge, anomalous magnetic moment). (author)
Roy–Steiner-equation analysis of pion–nucleon scattering
Directory of Open Access Journals (Sweden)
Meißner U.-G.
2017-01-01
Full Text Available 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.c
Roy-Steiner-equation analysis of pion-nucleon scattering
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.
Energy Technology Data Exchange (ETDEWEB)
He, Zhi-Yong [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; [Academia Sinica, Lanzhou, GS (China). Inst. of Modern Physics; Peter, J; Angelique, J C; Bizard, G; Brou, R; Cussol, D [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; Auger, A; Cabot, C; Crema, E [Grand Accelerateur National d` Ions Lourds (GANIL), 14 - Caen (France); Buta, A [Caen Univ., 14 (France). Lab. de Physique Corpusculaire; [Institute of Atomic Physics, Bucharest (Romania)] [and others
1996-09-01
Experimental measurement and theoretical comparison of collective flow can give important information about the nuclear equation of state (EOS) and the in-medium nucleon-nucleon cross section. Experimental measurements of {sup 64}Zn+{sup 27}Al collision from 35 to 79 MeV/u with the 4{pi} array MUR=TONNEAU are presented. The results are compared to BUU calculations. (K.A.).
Source composition of cosmic rays at high energy
International Nuclear Information System (INIS)
Juliusson, E.; Cesarsky, C.J.; Meneguzzi, M.; Casse, M.
1975-01-01
The source composition of the cosmic ray is usually calculated at an energy of a few GeV per nucleon. Recent measurements have however indicated that the source composition may be energy dependent. In order to give a quantitative answer to this question the source composition at 50GeV/nucleon has been calculated using an exponential distribution of path lengths and in the slab approximation. The results obtained at high energy agree very well with the source composition obtained at lower energies, except the abundance of carbon which is significantly lower than the generally accepted value of low energies [fr
Coherent production of high-energy photons and π mesons in heavy ion reactions
International Nuclear Information System (INIS)
Batkin, I.S.; Kopytin, I.V.
1986-01-01
A microscopic model of high-energy photon and pion production processes in collision of multicharged ions with kinetic energy of relative motion from 40 to 100 MeV per nucleon was constructed not using fitting parameters
The role of collision terms for nucleon emission in intermediate energy heavy ion reactions
International Nuclear Information System (INIS)
Gregoire, C.; Scheuter, F.; Remaud, B.; Sebille, F.
1984-01-01
A semi-classical description of heavy ion collisions is developed with a particular attention to the nucleon flux from one partner through the other one. The phase-space extension of the nucleons is explicitly treated by means of the Wigner transform of the density matrix. Its dynamical evolution is obtained by solving the Landau-Vlasov equation, where collision terms are explicitely introduced. As a matter of fact, the experimental nucleon spectra usually described by a thermal source with an intermediate velocity (around vsub(beam)/2) are interpreted in our framework by the coexistence of one-and two-body dissipation. Multi-differential cross-sections d 2 σ/dEdΩ are computed for the 12 C(86MeV/u) + 12 C system and are compared with the experimental data. Comparisons are also given for the 16 O (20 MeV/u) + 197 Au system
On light cluster production in nucleon induced reactions at intermediate energy
Energy Technology Data Exchange (ETDEWEB)
Lacroix, D.; Blideanu, V.; Durand, D
2004-09-01
A dynamical model dedicated to nucleon induced reaction between 30-150 MeV is presented. It considers different stages of the reaction: the approaching phase, the in-medium nucleon-nucleon collisions, the cluster formation and the secondary de-excitation process. The notions of influence area and phase-space exploration during the reaction are introduced. The importance of the geometry of the reaction and of the conservation laws are underlined. The model is able to globally reproduce the absolute cross sections for the emission of neutron and light charged particles for proton and neutron induced reactions on heavy and intermediate mass targets ({sup 56}Fe and {sup 208}Pb). (authors)
Directory of Open Access Journals (Sweden)
H. Mariji
2016-01-01
Full Text Available The nucleon single-particle energies (SPEs of the selected nuclei, that is, O16, Ca40, and Ni56, are obtained by using the diagonal matrix elements of two-body effective interaction, which generated through the lowest-order constrained variational (LOCV calculations for the symmetric nuclear matter with the Aυ18 phenomenological nucleon-nucleon potential. The SPEs at the major levels of nuclei are calculated by employing a Hartree-Fock inspired scheme in the spherical harmonic oscillator basis. In the scheme, the correlation influences are taken into account by imposing the nucleon effective mass factor on the radial wave functions of the major levels. Replacing the density-dependent one-body momentum distribution functions of nucleons, n(k,ρ, with the Heaviside functions, the role of n(k,ρ in the nucleon SPEs at the major levels of the selected closed shell nuclei is investigated. The best fit of spin-orbit splitting is taken into account when correcting the major levels of the nuclei by using the parameterized Wood-Saxon potential and the Aυ18 density-dependent mean field potential which is constructed by the LOCV method. Considering the point-like protons in the spherical Coulomb potential well, the single-proton energies are corrected. The results show the importance of including n(k,ρ, instead of the Heaviside functions, in the calculation of nucleon SPEs at the different levels, particularly the valence levels, of the closed shell nuclei.
High energy gamma-ray production in nuclear reactions
International Nuclear Information System (INIS)
Pinston, J.A.; Nifenecker, H.; Nifenecker, H.
1989-01-01
Experimental techniques used to study high energy gamma-ray production in nuclear reactions are reviewed. High energy photon production in nucleus-nucleus collisions is discussed. Semi-classical descriptions of the nucleus-nucleus gamma reactions are introduced. Nucleon-nucleon gamma cross sections are considered, including theoretical aspects and experimental data. High energy gamma ray production in proton-nucleus reactions is explained. Theoretical explanations of photon emission in nucleus-nucleus collisions are treated. The contribution of charged pion currents to photon production is mentioned
High-precision calculation of the strange nucleon electromagnetic form factors
Energy Technology Data Exchange (ETDEWEB)
Green, Jeremy [Johannes Gutenberg Univ., Mainz (Germany); Meinel, Stefan [Univ. of Arizona, Tucson, AZ (United States); Brookhaven National Lab. (BNL), Upton, NY (United States); Engelhardt, Michael G. [New Mexico State Univ., Las Cruces, NM (United States); Krieg, Stefan [Bergische Univ., Wuppertal (Germany); Julich Supercomputing Centre, Julich (Germany); Laeuchli, Jesse [College of William and Mary, Williamsburg, VA (United States); Negele, John W. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Orginos, Kostas [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Pochinsky, Andrew [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Syritsyn, Sergey [Brookhaven National Lab. (BNL), Upton, NY (United States)
2015-08-26
We report a direct lattice QCD calculation of the strange nucleon electromagnetic form factors G^{s}_{E} and G^{s}_{M} in the kinematic range 0 ≤ Q^{2} ≤ 1.2GeV^{2}. For the first time, both G^{s}_{E} and G^{s}_{M} are shown to be nonzero with high significance. This work uses closer-to-physical lattice parameters than previous calculations, and achieves an unprecented statistical precision by implementing a recently proposed variance reduction technique called hierarchical probing. We perform model-independent fits of the form factor shapes using the z-expansion and determine the strange electric and magnetic radii and magnetic moment. As a result, we compare our results to parity-violating electron-proton scattering data and to other theoretical studies.
Symbolic computation of the Hartree-Fock energy from a chiral EFT three-nucleon interaction at N2LO
International Nuclear Information System (INIS)
Gebremariam, B.; Bogner, S.K.; Duguet, T.
2010-01-01
We present the first of a two-part Mathematica notebook collection that implements a symbolic approach for the application of the density matrix expansion (DME) to the Hartree-Fock (HF) energy from a chiral effective field theory (EFT) three-nucleon interaction at N 2 LO. The final output from the notebooks is a Skyrme-like energy density functional that provides a quasi-local approximation to the non-local HF energy. In this paper, we discuss the derivation of the HF energy and its simplification in terms of the scalar/vector-isoscalar/isovector parts of the one-body density matrix. Furthermore, a set of steps is described and illustrated on how to extend the approach to other three-nucleon interactions. Program summary: Program title: SymbHFNNN; Catalogue identifier: AEGC v 1 0 ; Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEGC_v1_0.html; Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland; Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html; No. of lines in distributed program, including test data, etc.: 96 666; No. of bytes in distributed program, including test data, etc.: 378 083; Distribution format: tar.gz; Programming language: Mathematica 7.1; Computer: Any computer running Mathematica 6.0 and later versions; Operating system: Windows Xp, Linux/Unix; RAM: 256 Mb; Classification: 5, 17.16, 17.22; Nature of problem: The calculation of the HF energy from the chiral EFT three-nucleon interaction at N 2 LO involves tremendous spin-isospin algebra. The problem is compounded by the need to eventually obtain a quasi-local approximation to the HF energy, which requires the HF energy to be expressed in terms of scalar/vector-isoscalar/isovector parts of the one-body density matrix. The Mathematica notebooks discussed in this paper solve the latter issue. Solution method: The HF energy from the chiral EFT three-nucleon interaction at N 2 LO is cast into a form suitable for an automatic
Excitation energy partition in deeply inelastic collisions between 40Ar and Ag at 27 MeV per nucleon
International Nuclear Information System (INIS)
Borderie, B.; Rivet, M.F.; Cabot, C.; Fuchs, H.; Gardes, D.; Hanappe, F.; Jouan, D.; Montoya, M.
1991-01-01
The dynamics of the two partners produced in dissipative collisions has been experimentally studied for the system 40 Ar+Ag at 27 MeV per nucleon. Primary masses of the fragments can then be calculated; the excitation energy partition between the two fragments is derived from the number of particles evaporated by each fragment. We found that this division evolves from equipartition to a repartition close to thermal equilibrium in the excitation energy range 300-350 MeV or interaction times 5-10x10 -22 s. (orig.)
International Nuclear Information System (INIS)
Bond, A.
1977-01-01
The present position of nucleonic techniques for process measurements, is considered from the technical and cost viewpoints. Systems considered include level, density, thickness (including coating thickness), moisture, and sulphur in hydrocarbons gauges and also belt weighers. The advantages of such systems are discussed and the cost-benefit position considered. The combination of nucleonic measuring equipment with a microcomputer is examined. (U.K.)
Proceedings of the workshop on two-nucleon system
International Nuclear Information System (INIS)
Kawaguchi, Masaaki; Namiki, Mikio; Fukawa, Mineo; Masaike, Akira
1980-08-01
The workshop on two nucleon system started its works four years ago to promote the experiment project on nucleon-nucleon system in the National Laboratory for High Energy Physics by the close cooperation of experimenters and theorists. In particular, several proposals have been made about the experiments using the polarized targets of hydrogen and deuterium, the spectrometers of large solid angle and others, and the investigation into them have been forwarded. It was decided to publish the results of the fourth meeting held in the National Laboratory for High Energy Physics on October 19 and 20, 1979, as the interim report, summarizing the contents. Some of the initial objectives have not been realized yet, but the data have been produced gradually from the experiments in the National Laboratory for High Energy Physics, and are contributing to various analyses. This report is composed of the physics of nucleon-nucleon systems and anti-nucleon-nucleon systems, the results of experiments and the projects corresponding to them, and the hypothetic round-table talk on the points which this workshop considers as problematic and the views of outside researchers on the National Laboratory for High Energy Physics. Finally, the materials distributed at the time of the meeting are added for reference as the appendix. Some numerical values are mutually different, but adjustment was not made. (Kako, I.)
Multi-quark effects in high energy nucleon-nucleon and nucleus-nucleus collisions
International Nuclear Information System (INIS)
Besliu, C.; Caraciuc, I.; Jipa, A.; Olariu, A.; Topor-Pop, R.; Cotorobai, F.; Pantea, D.; Popa, L.; Popa, V.; Topor-Pop, V.
1988-02-01
Recent data obtained in two experiments performed in the framework of the Bucharest-Dubna collaboration are presented, i.e.: the observation of narrow dibaryonic resonances is neutron-proton interactions in 1mHBC at different momenta of incident neutrons in the range 1-5 GeV/c, and the cumulative production of negative pions in nucleus-nucleus interactions in SKM-200 streamer chamber at 4.5 GeV/c. (authors)
Exchange currents in low-energy nucleon capture by 3He
International Nuclear Information System (INIS)
Wervelman, Rob.
1991-01-01
The studies described in this thesis concern absolute cross-section measurements of the radiative neutron capture reactions 3 He (n,γ) 4 He and 3 He(n,γγ) 4 He, and are complements with shell-model calculations on the radiative thermal neutron capture reaction by 3 He and on the weak 3 He(p,e + ν e ) 4 He reaction. The experiments have been performed at two neutron energies, with sub-thermal neutrons where s-wave capture is dominant, and with a quasi-monochromatic 24.5 keV neutron beam (p-wave capture). It has been found that the thermal neutron capture cross section of 3 He is 55±3 μb. Measured at 24.5 keV-neutron energy, the radiative capture cross section for p-wave neutrons turned out to be 9.1±0.8 μb. A measurement on the double-photon reaction 3 He(n th ,γγ) has yielded a cross-section value of 30±80 μb. In the theoretical part of the work a standard model of nuclear weak and electromagnetic interaction currents, consisting of a one-body impulse approximation and a two-body meson-exchange current part, has been applied to the process of nucleon capture by 3 He. Within the framework of a (0+2) (h/2π)ω shell-model calculation, using Sussex matrix elements for the 3 He and 4 He ground state wave functions, the empirical radiative cross sections for thermal neutrons of 3 He could be reproduced with satisfactory agreement. The total MEC correction to the radiative thermal neutron capture cross section is rather small because large cancellations occur between the various contributions. In the 3 He(p,e + ν e ) 4 He reaction meson-exchange contributions enlarge the astrophysical S-factor by more than a factor two. The matrix element ratio of the weak 3 He+p and the electromagnetic 3 He+n reaction is calculated to be (4.3±0.6)g A C 0 . This ratio has been found to be fairly insensitive to the percentage D-state admixtures in the 3 He and 4 He ground state wave functions. (author). 129 refs.; 24 figs.; 5 tabs
International Nuclear Information System (INIS)
Ishibashi, K.; Miura, Y.; Sakae, T.
1990-01-01
In the present study, intranuclear nucleons with a high momentum are introduced into intranuclear cascade calculation, and the preequilibrium effects are considered at the end of the cascade process. The improvements made in the HETC (High Energy Transport Code) are outlined, focusing on intranuclear nucleons with a high momentum, and termination of the intranuclear cascade process. Discussion is made of the cutoff energy, and Monte Carlo calculations based on an excitation model are presented and analyzed. The experimental high energy neutrons in the backward direction are successfully reproduced. The preequilibrium effect is considered in a local manner, and this is introduced as a simple probability density function for terminating the intranuclear cascade process. The resultant neutron spectra reproduce the shoulders of the experimental data in the region of 20 to 50 MeV. The exciton model is coded with a Monte Carlo algorithm. The results of the exciton model calculation is not so appreciable except for intermediate energy neutrons in the backward direction. (N.K.)
2002-01-01
% EMU15 \\\\ \\\\ The aim of this experiment is to investigate high energy heavy ion central collisions by the use of emulsion magnetic chamber with high spatial resolution. The emulsion chamber consists of 50~emulsion layers 50~microns thick each coated on 25~microns mylar base. A thin lead target plate 300~microns thick is installed immediately in front of the first emulsion layer. It is placed in the transverse magnetic field B~$\\sim$~2~Tesla and is to be installed perpendicularly to Pb nucleus beam. This set-up enables to measure full 3-momenta and charge signs of secondary particles. \\\\ \\\\Specific goal is to carry out detailed analysis of individual events with super high multiplicity of secondaries. These data are to be used for investigation of properties of super hot/dense matter, in particular to look for and analyze possible manifestations of quark-gluon plasma in central Pb-Pb collisions at energies of 160~GeV/nucleon.
Pion-nucleon scattering: from chiral perturbation theory to Roy-Steiner equations
Kubis, Bastian; Hoferichter, Martin; de Elvira, Jacobo Ruiz; Meißner, Ulf-G.
2016-11-01
Ever since Weinberg's seminal predictions of the pion-nucleon scattering amplitudes at threshold, this process has been of central interest for the study of chiral dynamics involving nucleons. The scattering lengths or the pion-nucleon σ-term are fundamental quantities characterizing the explicit breaking of chiral symmetry by means of the light quark masses. On the other hand, pion-nucleon dynamics also strongly affects the long-range part of nucleon-nucleon potentials, and hence has a far-reaching impact on nuclear physics. We discuss the fruitful combination of dispersion-theoretical methods, in the form of Roy-Steiner equations, with chiral dynamics to determine pion-nucleon scattering amplitudes at low energies with high precision.*
Spin polarization of 34Al fragments produced by nucleon pickup at intermediate energies
International Nuclear Information System (INIS)
Turzo, K.; Himpe, P.; Borremans, D.; Mallion, S.; Neyens, G.; Vermeulen, N.; Yordanov, D.; Balabanski, D.L.; Belier, G.; Daugas, J.M.; Georgiev, G.; Oliveira de Santos, F.; Matea, I.; Stodel, Ch.; Penionzhkevich, Yu. E.
2006-01-01
The polarization of 34 Al fragments, produced by single neutron pickup from a 9 Be target by a 36 S projectile at 77.5 MeV/nucleon, have been observed at GANIL via the detection of resonantly destroyed β-asymmetry. The reaction-induced polarization is deduced using a tentative spin/parity assignment for the 34 Al ground state. A positive polarization was measured near the peak of the 34 Al yield curve. A kinematical model based on the spectator-participant model for projectile fragmentation reactions has been extended in order to take into account the features of pickup reactions, i.e., the picked-up nucleon having an average momentum equal to the Fermi momentum and aligned along the incident beam direction. The trend-line in the observed spin-orientation is very well reproduced by this model
Block, Martin M
2002-01-01
Using an eikonal structure for the scattering amplitude, factorization theorems for nucleon-nucleon, gamma p and gamma gamma scattering at high energies have been derived, using only some very general assumptions. Using a QCD-inspired eikonal analysis of nucleon-nucleon scattering, we present here experimental confirmation for factorization of cross sections, nuclear slope parameters B and rho -values (ratio of real to imaginary portion of forward scattering amplitudes), showing that: 1) the three factorization theorems of Block and Kaidalov [2000] hold, 2) the additive quark model holds to approximately=1%, and 3) vector dominance holds to better than approximately=4%. Predictions for the total cross section, elastic cross section and other forward scattering parameters at the LHC (14 TeV) are given. (12 refs).
Ciofi degli Atti, Claudio; Mezzetti, Chiara Benedetta; Morita, Hiko
2017-04-01
Background: Two-nucleon (2 N ) short-range correlations (SRC) in nuclei have been recently thoroughly investigated, both theoretically and experimentally and the study of three-nucleon (3 N ) SRC, which could provide important information on short-range hadronic structure, is underway. Novel theoretical ideas concerning 2 N and 3 N SRC are put forward in the present paper. Purpose: The general features of a microscopic one-nucleon spectral function which includes the effects of both 2 N and 3 N SRC and its comparison with ab initio spectral functions of the three-nucleon systems are illustrated. Methods: A microscopic and parameter-free one-nucleon spectral function expressed in terms of a convolution integral involving ab initio relative and center-of-mass (c.m.) momentum distributions of a 2 N pair and aimed at describing two- and three-nucleon short-range correlations, is obtained by using: (i) the two-nucleon momentum distributions obtained within ab initio approaches based upon nucleon-nucleon interactions of the Argonne family; (ii) the exact relation between one- and two-nucleon momentum distributions; (iii) the fundamental property of factorization of the nuclear wave function at short internucleon ranges. Results: The comparison between the ab initio spectral function of 3He and the one based upon the convolution integral shows that when the latter contains only two-nucleon short-range correlations the removal energy location of the peaks and the region around them exhibited by the ab initio spectral function are correctly predicted, unlike the case of the high and low removal energy tails; the inclusion of the effects of three-nucleon correlations brings the convolution model spectral function in much better agreement with the ab initio one; it is also found that whereas the three-nucleon short-range correlations dominate the high energy removal energy tail of the spectral function, their effects on the one-nucleon momentum distribution are almost one
The transverse-energy distributions of 32S-nucleus collisions at 200 GeV per nucleon
International Nuclear Information System (INIS)
Akesson, T.; Atherton, H.; Beker, H.; Bettoni, D.; Boeggild, H.; Dederichs, K.; Devenish, R.C.E.; En'yo, H.; Esten, M.J.; Fabjan, C.W.; Mazzoni, M.A.; Nilsson, S.; Piuz, F.; Poulard, G.; Price, M.; Russ, J.; Schukraft, J.; Sekimoto, M.; Seman, M.; Shotton, P.; Sletten, H.; Thodberg, H.H.; Veenhof, R.; Wigmans, R.; Willis, W.; Almehed, S.; Haglund, R.; Hedeberg, V.; Johansson, S.; Loerstad, B.; Mjoernmark, U.; Angelis, A.L.S.; Dodd, J.R.; Lessard, L.; McCubbin, M.L.; Armenise, N.; Muciaccia, M.T.; Simone, S.; Aubry, P.; Beaudoin, G.; Beaulieu, J.M.; Depommier, P.; Lounis, A.; Bartels, H.W.; Drees, A.; Fischer, P.; Glaessel, P.; Goerlach, U.; Hoelscher, A.; Kroh, V.; Neubert, M.; Pfeiffer, A.; Specht, H.J.; Benary, O.; Dagan, S.; Heifetz, R.; Marzari-Chiesa, A.; Masera, M.; Oren, Y.; Bisi, V.; Giubellino, P.; Ramello, L.; Riccati, L.; Blevis, I.; Fraenkel, Z.; Tserruya, I.; Cleland, W.; Clemen, M.; Collick, B.; Murray, M.; Park, Y.M.; Thompson, J.; Corriveau, F.; Hamel, L.A.; Jarlskog, G.; Lamarche, F.; Leroy, C.; Mazzucato, E.; Sirois, Y.; Dell'Uomo, S.; Di Liberto, S.; Meddi, F.; Rosa, G.; DiGiacomo, N.; Van Hecke, H.; Jacak, B.; McGaughey, P.; Sondheim, W.; Sunier, J.; Dolgoshein, B.; Kalinovski, A.; Kantserov, A.; Nevski, P.; Smirnov, S.; Sumarokov, A.; Tcherniatin, V.; Tikhomirov, V.; Berlandsson, B.; Sellden, B.; Gaidot, A.; Gibrat-Debu, F.; London, G.; Pansart, J.P.; Vasseur, G.; McCubbin, N.A.; Romano, G.; Sidorov, V.
1988-01-01
Transverse-energy distributions have been measured for the collisions of the 32 S nucleus with Al, Ag, W, Pt, Pb and U target nuclei, at an incident energy of 200 GeV per nucleon. The shapes of these distribution reflect the geometry of the collisions, including the deformation effects. For central collisions, the transverse-energy production in the region -0.1 lab 0.5 , where A is the atomic mass number of the target. This increase is accompanied by a relative depletion in the forward region η lab > 2.9. These results are compared with those obtained under similar conditions with incident 16 O nuclei. A comparison is also made with the predictions of a Monte Carlo generator based on the dual parton model. Finally, we give estimates of the energy density reached and its dependence on the atomic mass number of the projectile. (orig.)
QCD and high-energy nuclear collisions
CERN. Geneva
2007-01-01
Six years ago, Relativistic Heavy Ion Collider at Brookhaven started colliding heavy nuclei at record center-of-mass energies of up to 200 GeV/nucleon. Very soon, the Large Hadron Collider at CERN will push the energy of the ions to an astounding 5 TeV/nucleon. What can be learnt from the experiments at these machines? What do we know about the physics of super--dense matter already? I will argue that heavy ion accelerators bring us to the new frontiers of physical knowledge by creating strong color fields and very high densities of partons, at which qualitatively new phenomena emerge. I will also discuss the cross-disciplinary implications for cosmology, astrophysics, and connections to condensed matter physics.
Nucleon-nucleon momentum correlation function for light nuclei
International Nuclear Information System (INIS)
Ma, Y.G.; 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.; Wei, Y.B.; Yan, T.Z.
2007-01-01
Nucleon-nucleon momentum correlation function have been presented for nuclear reactions with neutron-rich or proton-rich projectiles using a nuclear transport theory, namely Isospin-Dependent Quantum Molecular Dynamics model. The relationship between the binding energy of projectiles and the strength of proton-neutron correlation function at small relative momentum has been explored, while proton-proton correlation function shows its sensitivity to the proton density distribution. Those results show that nucleon-nucleon correlation function is useful to reflect some features of the neutron- or proton-halo nuclei and therefore provide a potential tool for the studies of radioactive beam physics
Coupled channels Marchenko inversion for nucleon-nucleon potentials
International Nuclear Information System (INIS)
Kohlhoff, H.; Geramb, H.V. von
1994-01-01
Marchenko inversion is used to determine local energy independent but channel dependent potential matrices from optimum sets of experimental phase shifts. 3 SD 1 and 3 PF 2 channels of nucleon-nucleon systems contain in their off-diagonal potential matrices explicitly the tensor force for T = 0 and 1 isospin. We obtain, together with single channels, complete sets of quantitative nucleon-nucleon potential results which are ready for application in nuclear structure and reaction analyses. The historic coupled channels inversion result of Newton and Fulton is revisited. (orig.)
Semi-phenomenological model of the nucleon-nucleon interaction
International Nuclear Information System (INIS)
Houriet, A.; Bagnoud, Y.
1977-01-01
A nucleon with isobars is used to elaborate a model of the nucleon-nucleon interaction at low energy (Esub(CM) 2 sub(r), the pion-nucleon renormalized coupling constant. The model establishes a very good coordination for deuteron and p-p scattering-polarization measurements ( 1 K 0 , 1 D 2 , 1 G 4 phase shifts), and permits the determination of f 2 sub(r) for every independent experimental value. For 21 such values, the mean value 2 sub(r)>=0.0785 with Δf 2 sub(r)=0.0024(3%) is obtained. (Auth.)
International Nuclear Information System (INIS)
Simon, G.G.
1978-01-01
In this thesis results of measurements of the differential cross sections of the elastic and inelastic electron deuteron scattering are presented. The data were taken at several scattering angles and in the electron energy range of 150 MeV up to 320 MeV. The extracted form factors and structure functions are compared with theoretical results which are sensitive to details of nucleon structure and of the nucleon-nucleon forces. (FKS)
Nucleon-nucleon forces in the quark compound bag model and few-nucleon systems
International Nuclear Information System (INIS)
Kalashnikova, Yu.S.; Narodetskij, I.M.
1984-01-01
Role of quark-gluon degrees of freedom is discussed in nucleon-nucleon scattering at low and intermediate energies. It is shown that the existence of six-quark hags fixes the form of NN potential at small distances, which leads to the P-matrix satisfying the criterion of Jaffe and Low. The dynamical model of three-nucleon system is discussed taking into accoint the contribution of six-quark bags
2002-01-01
This experiment is a high statistics exposure of BEBC filled with hydrogen to both @n and &bar.@n beams. The principal physics aims are : \\item a) The study of the production of charmed mesons and baryons using fully constrained events. \\end{enumerate} b) The study of neutral current interactions on the free proton. \\item c) Measurement of the cross-sections for production of exclusive final state N* and @D resonances. \\item d) Studies of hadronic final states in charged and neutral current reactions. \\item e) Measurement of inclusive charged current cross-sections and structure functions. \\end{enumerate}\\\\ \\\\ The neutrino flux is determined by monitoring the flux of muons in the neutrino shield. The Internal Picket Fence and External Muon Identifier of BEBC are essential parts of the experiment. High resolution cameras are used to search for visible decays of short-lived particles.
High-quality two-nucleon potentials up to fifth order of the chiral expansion
Entem, D. R.; Machleidt, R.; Nosyk, Y.
2017-08-01
We present NN potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO ). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate π N low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira, and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The NN potentials are fit to the world NN data below the pion-production threshold of the year 2016. The potential of the highest order (N4LO ) reproduces the world NN data with the outstanding χ2/datum of 1.15, which is the highest precision ever accomplished for any chiral NN potential to date. The NN potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is nonlocal and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.
Consistent, high-quality two-nucleon potentials up to fifth order of the chiral expansion
Machleidt, R.
2018-02-01
We present N N potentials through five orders of chiral effective field theory ranging from leading order (LO) to next-to-next-to-next-to-next-to-leading order (N4LO). The construction may be perceived as consistent in the sense that the same power counting scheme as well as the same cutoff procedures are applied in all orders. Moreover, the long-range parts of these potentials are fixed by the very accurate πN low-energy constants (LECs) as determined in the Roy-Steiner equations analysis by Hoferichter, Ruiz de Elvira and coworkers. In fact, the uncertainties of these LECs are so small that a variation within the errors leads to effects that are essentially negligible, reducing the error budget of predictions considerably. The N N potentials are fit to the world N N data below pion-production threshold of the year of 2016. The potential of the highest order (N4LO) reproduces the world N N data with the outstanding χ 2/datum of 1.15, which is the highest precision ever accomplished for any chiral N N potential to date. The N N potentials presented may serve as a solid basis for systematic ab initio calculations of nuclear structure and reactions that allow for a comprehensive error analysis. In particular, the consistent order by order development of the potentials will make possible a reliable determination of the truncation error at each order. Our family of potentials is non-local and, generally, of soft character. This feature is reflected in the fact that the predictions for the triton binding energy (from two-body forces only) converges to about 8.1 MeV at the highest orders. This leaves room for three-nucleon-force contributions of moderate size.
International Nuclear Information System (INIS)
Gebremariam, B.; Bogner, S.K.; Duguet, T.
2011-01-01
The density matrix expansion (DME) of Negele and Vautherin is a convenient tool to map finite-range physics associated with vacuum two- and three-nucleon interactions into the form of a Skyrme-like energy density functional (EDF) with density-dependent couplings. In this work, we apply the improved formulation of the DME proposed recently in (arXiv:0910.4979) by Gebremariam et al. to the non-local Fock energy obtained from chiral effective field theory (EFT) two-nucleon (NN) interactions at next-to-next-to-leading-order (N 2 LO). The structure of the chiral interactions is such that each coupling in the DME Fock functional can be decomposed into a coupling constant arising from zero-range contact interactions and a coupling function of the density arising from the universal long-range pion exchanges. This motivates a new microscopically-guided Skyrme phenomenology where the density-dependent couplings associated with the underlying pion-exchange interactions are added to standard empirical Skyrme functionals, and the density-independent Skyrme parameters subsequently refit to data. A link to a downloadable Mathematica notebook containing the novel density-dependent couplings is provided.
Unveiling the strangeness secrets: low-energy kaon-nucleon/nuclei interactions studies at DAΦNE
Directory of Open Access Journals (Sweden)
Curceanu C.
2014-03-01
Full Text Available The DAΦNE electron-positron collider at the Laboratori Nazionali di Frascati of INFN, Italy has made available a unique quality low-energy negatively charged kaons “beam”, which is used to unveil the secrets of the kaon-nucleon/nuclei interactions at low energies by the SIDDHARTA-2 and AMADEUS experiments. SIDDHARTA has already performed unprecedented precision measurements of kaonic atoms, and is being presently upgraded, as SIDDHARTA-2, to approach new frontiers. The AMADEUS experiment plans to perform in the coming years precision measurements on kaon-nuclei interactions at low-energies, to study the possible formation of kaonic nuclei, of the Λ(1405 and of many other processes involving strangeness.
The reaction 12C + 12C at bombarding energies from 5 to 10 MeV per nucleon
International Nuclear Information System (INIS)
Morsad, A.
1986-01-01
The reaction 12 C + 12 C has been studied for energies ranging from E LAB = 60 to 120 MeV. The excitation functions and angular distributions were obtained for the elastic (0 + , 0 + ) and inelastic (2 + , 0 + ), (2 + , 2 + ) channels as well as for the transfer channels of one and two nucleons. For the transfer reactions, the feeding of the final bound states was very selective. Narrow correlated structures were found in the transfer and especially in the elastic and inelastic channels. In this energy range, there appears to be a transition from surface transparency to interference phenomena. The optical model in its simplest form is unable to describe the elastic scattering at large angles. This has been interpreted as a consequence of the coupling between the elastic and inelastic channels which is particularly strong of these energies. 80 refs [fr
International Nuclear Information System (INIS)
Bonner, B.E.; Roberts, J.B. Jr.
1993-01-01
We report here on progress made for the period from December 1, 1992 (the date of submission of our latest progress report) to November 30, 1993 for DOE Grant No. DE-FG05-92ER40717. The new results from the SMC experiment have generated a buzz of theoretical activity. Our involvement with the D0 experiment and the upgrade has increased substantially during the past two years so that we now have six people heavily committed and making what can only be described as a large and disproportionate impact on D0 physics output. Some of the new developments made here at Rice in Neural Network and Probability Density Estimation techniques for data analysis promise to have applications both in D0 and beyond. We report a load of new results from our high-p t jet photoproduction experiment. In addition we have been working on KTeV, albeit without having adequate funding for this work. Progress on the theoretical front has been nothing short of amazing, as is reported herein. In a grand lecture tour during this sabbatical year, Paul Stevenson has already reported his breakthroughs at ten institutions, including CERN, Oxford, Cambridge, Rutherford Lab, Imperial College, and Durham University. The group at Rice University has had an exceptionally productive year and we are justifiably proud of the progress which is reported here
International Nuclear Information System (INIS)
Steckmeyer, J.C.; Genouin-Duhamel, E.; Vient, E.; Colin, J.; Durand, D.; Auger, G.; Bacri, C.O.; Bellaize, N.; Borderie, B.; Bougault, R.; Bouriquet, B.; Brou, R.; Buchet, P.; Charvet, J.L.; Chbihi, A.; Cussol, D.; Dayras, R.; De Cesare, N.; Demeyer, A.; Dore, D.; Frankland, J.D.; Galichet, E.; Gerlic, E.; Guinet, D.; Hudan, S.; Lautesse, P.; Lavaud, F.; Laville, J.L.; Lecolley, J.F.; Leduc, C.; Legrain, R.; Le Neindre, N.; Lopez, O.; Louvel, M.; Maskay, A.M.; Nalpas, L.; Normand, J.; Parlog, M.; Pawlowski, P.; Plagnol, E.; Rivet, M.F.; Rosato, E.; Saint-Laurent, F.; Tabacaru, G.; Tamain, B.; Tassan-Got, L.; Tirel, O.; Turzo, K.; Vigilante, M.; Volant, C.; Wieleczko, J.P.
2001-01-01
The excitation energy and angular momentum transferred to quasiprojectiles have been measured in the 129 Xe+ nat Sn collisions at bombarding energies between 25 and 50 MeV/nucleon. The excitation energy of quasiprojectiles has been determined from the kinetic energy of all decay products (calorimetry). It increases with the violence of the collision, approaching 10 MeV/nucleon in the most dissipative ones. The angular momentum has been deduced from the kinetic energies and angular distributions of the emitted light charged particles (p, d, t, 3 He and α). The (apparent) spin value decreases with the violence of the collision. Larger spin values are observed at the lowest bombarding energy. Data are compared with the predictions of dynamical and statistical models. They reproduce the data in a quantitative way indicating that large spin values are transferred to quasiprojectiles during the interaction. The results show that the one-body dissipation formalism still applies at intermediate bombarding energies and low-energy dissipations. With the increase of the energy, the data seem to be better described when the two-body interaction is accounted for
Hadron-nucleon inelastic collision mean free path in nuclear matter
International Nuclear Information System (INIS)
Strugalski, Z.
1980-01-01
Characteristics of atomic nuclei, used as targets in high energy hadron-nucleus collision experiments, are defined on the basis of the data on the nuclei sizes and radial nucleon density distributions in nuclei. Average mean free path for inelastic hadron-nucleon collisions in nuclei is estimated using existing experimental data on the pion-xenon nucleus collisions and the connection of it with the cross-section for hadron-nucleon elementary inelastic collisions is discussed
The spin structure of the nucleon
International Nuclear Information System (INIS)
Deur, A.
2008-02-01
This document describes the recent experimental results on the spin structure of the nucleon obtained with the electron accelerator Thomas Jefferson National Facility (Jefferson Lab), Virginia. We first discuss the goal of studying the nucleon spin structure and give the basis and phenomenology of high energy lepton scattering. Then, we discuss with some details a few sum rules concerning the spin structure of the nucleon. Those are important tools for studying the nucleon spin structure at Jefferson Lab. We then describe the present experimental situation and analyze the results. We have been able to determine an effective coupling constant for the strong interaction for any regime of quantum chromodynamics which proves that QCD is an approximately conformal theory. We conclude on the perspectives for this field of research, in particular with the 12 GeV energy upgrade of Jefferson Lab. The top priority will be the measurement of generalised parton distributions. The only issue that will stay misunderstood is the role of the very low x domain on the spin structure of the nucleon
Nuclear reactions induced by high-energy alpha particles
Shen, B. S. P.
1974-01-01
Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.
International Nuclear Information System (INIS)
Xu Chang; Li Baoan; Chen Liewen
2010-01-01
Based on the Hugenholtz-Van Hove theorem, it is shown that both the symmetry energy E sym (ρ) and its density slope L(ρ) at normal density ρ 0 are completely determined by the nucleon global optical potentials. The latter can be extracted directly from nucleon-nucleus scatterings, (p,n) charge-exchange reactions, and single-particle energy levels of bound states. Averaging all phenomenological isovector nucleon potentials constrained by world data available in the literature since 1969, the best estimates of E sym (ρ 0 )=31.3 MeV and L(ρ 0 )=52.7 MeV are simultaneously obtained. Moreover, the corresponding neutron-proton effective mass splitting in neutron-rich matter of isospin asymmetry δ is estimated to be (m n * -m p * )/m=0.32δ.
Evaluation of the three-nucleon analyzing power puzzle
International Nuclear Information System (INIS)
Tornow, W.; Witala, H.
1998-01-01
The current status of the three-nucleon analyzing power puzzle is reviewed. Applying tight constraints on the allowed deviations between calculated predictions and accepted values for relevant nucleon-nucleon observables reveals that energy independent correction factors applied to the 3 P j nucleon-nucleon interactions can not solve the puzzle. Furthermore, using the same constraints, charge-independence breaking in the 3 P j nucleon-nucleon interactions can be ruled out as a possible tool to improve the agreement between three-nucleon calculations and data. The study of the energy dependence of the three-nucleon analyzing power puzzle gives clear evidence that the 3 P j nucleon-nucleon interaction obtained from phase-shift analyses and used in potential models are correct above about 25 MeV, i.e., the 3 P j nucleon-nucleon interactions have to be modified only at lower energies in order to solve the three-nucleon analyzing power puzzle, unless new three-nucleon forces can be found that account for the three-nucleon analyzing power puzzle without destroying the beautiful agreement between rigorous three-nucleon calculations and a large body of accurate three-nucleon data. (orig.)
Evaluation of the three-nucleon analyzing power puzzle
Energy Technology Data Exchange (ETDEWEB)
Tornow, W. [Duke Univ., Durham, NC (United States). Dept. of Physics]|[Triangle Univ. Nuclear Lab., Durham, NC (United States); Witala, H. [Uniwersytet Jagiellonski, Cracow (Poland). Inst. Fizyki
1998-07-20
The current status of the three-nucleon analyzing power puzzle is reviewed. Applying tight constraints on the allowed deviations between calculated predictions and accepted values for relevant nucleon-nucleon observables reveals that energy independent correction factors applied to the {sup 3}P{sub j} nucleon-nucleon interactions can not solve the puzzle. Furthermore, using the same constraints, charge-independence breaking in the {sup 3}P{sub j} nucleon-nucleon interactions can be ruled out as a possible tool to improve the agreement between three-nucleon calculations and data. The study of the energy dependence of the three-nucleon analyzing power puzzle gives clear evidence that the {sup 3}P{sub j} nucleon-nucleon interaction obtained from phase-shift analyses and used in potential models are correct above about 25 MeV, i.e., the {sup 3}P{sub j} nucleon-nucleon interactions have to be modified only at lower energies in order to solve the three-nucleon analyzing power puzzle, unless new three-nucleon forces can be found that account for the three-nucleon analyzing power puzzle without destroying the beautiful agreement between rigorous three-nucleon calculations and a large body of accurate three-nucleon data. (orig.) 18 refs.
Toyokawa, Masakazu; Yahiro, Masanobu; Matsumoto, Takuma; Kohno, Michio
2018-02-01
An important current subject is to clarify the properties of chiral three-nucleon forces (3NFs) not only in nuclear matter but also in scattering between finite-size nuclei. Particularly for elastic scattering, this study has just started and the properties are not understood for a wide range of incident energies (E_in). We investigate basic properties of chiral 3NFs in nuclear matter with positive energies by using the Brueckner-Hartree-Fock method with chiral two-nucleon forces at N3LO and 3NFs at NNLO, and analyze the effects of chiral 3NFs on 4He elastic scattering from targets ^{208}Pb, ^{58}Ni, and ^{40}Ca over a wide range of 30 ≲ E_in/A_P ≲ 200 MeV by using the g-matrix folding model, where A_P is the mass number of the projectile. In symmetric nuclear matter with positive energies, chiral 3NFs make the single-particle potential less attractive and more absorptive. The effects mainly come from the Fujita-Miyazawa 2π-exchange 3NF and become slightly larger as E_in increases. These effects persist in the optical potentials of 4He scattering. As for the differential cross sections of 4He scattering, chiral-3NF effects are large for E_in/A_P ≳ 60 MeV and improve the agreement of the theoretical results with the measured ones. Particularly for E_in/A_P ≳ 100 MeV, the folding model reproduces measured differential cross sections pretty well. Cutoff (Λ) dependence is investigated for both nuclear matter and 4He scattering by considering two cases of Λ=450 and 550 MeV. The uncertainty coming from the dependence is smaller than chiral-3NF effects even at E_in/A_P=175 MeV.
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
Mean free paths for high energy hadron collisions in nuclear matter
International Nuclear Information System (INIS)
Strugalski, Z.
1983-01-01
The mean free paths for various collisions of high energy pion in nuclear matter are determined experimentally using pion-xenon nucleus collision events at 3.5 GeV/c momentum. The relation between the mean free path lambdasub(i) for hadron-nucleon particle producing collisions in nuclear matter and corresponding cross section σsub(i) for particle producing collisions of this hadron with free nucleon is derived and discussed. This relation is lambdasub(i)=k/σsub(i), where lambdasub(i) is in nucleons per fm 2 and σ sub(i) - in fm 2 per nucleon, correspondingly, k=3.00+-0.26 is a coefficient accounting for the display of the nucleon inner structure in hadron-nucleus collisions
QCD in high-energy proton-proton and proton-antiproton collisions
International Nuclear Information System (INIS)
Baier, R.
1985-01-01
The experimental and theoretical investigation of nucleon-nucleon collisions at high energies allows to explore the structure of the nucleon by large momentum transfer (deep-inelastic) processes. In these lectures the structure of the nucleon from momentum scales Q > 1 GeV/c ( -16 cm) is discussed. In the first lecture the basic concepts of the parton model and of perturbative quantum chromodynamics (QCD) are introduced, and applied to deep inelastic lepton-nucleon scattering. The following lectures cover large transverse momentum, psub(T), hadronic processes, massive dilepton production and production of prompt real photons at large psub(T). The present status of the theoretical understanding of these processes is summarized. (Auth.)
International Nuclear Information System (INIS)
Toke, J.; Planeta, R.; Schroeder, W.U.; Huizenga, J.R.
1991-01-01
Data from a kinematical coincidence experiment on the damped reaction 165 Ho+ 74 Ge at 8.5 MeV/nucleon have been reanalyzed. Although the new analysis confirms the presence of some correlations between the excitation-energy division and the mass asymmetry, the magnitude of these correlations is found to be significantly smaller than that previously reported. Proton-neutron symmetry of the mechanism of heat generation through nucleon exchange is revealed and a possible acceptor-donor asymmetry of this mechanism is discussed
Pion–nucleon scattering: from chiral perturbation theory to Roy–Steiner equations
International Nuclear Information System (INIS)
Kubis, Bastian; Hoferichter, Martin; Elvira, Jacobo Ruiz de; Meißner, Ulf-G.
2016-01-01
Ever since Weinberg’s seminal predictions of the pion–nucleon scattering amplitudes at threshold, this process has been of central interest for the study of chiral dynamics involving nucleons. The scattering lengths or the pion–nucleon σ-term are fundamental quantities characterizing the explicit breaking of chiral symmetry by means of the light quark masses. On the other hand, pion–nucleon dynamics also strongly affects the long-range part of nucleon–nucleon potentials, and hence has a far-reaching impact on nuclear physics. We discuss the fruitful combination of dispersion-theoretical methods, in the form of Roy–Steiner equations, with chiral dynamics to determine pion–nucleon scattering amplitudes at low energies with high precision.
Vonta, N.; Souliotis, G. A.; Loveland, W. D.; Kwon, Y. K.; Tshoo, K.; Jeong, S. C.; Veselsky, M.; Bonasera, A.; Botvina, A.
2016-01-01
We investigate the possibilities of producing neutron-rich nuclides in projectile fission of heavy beams in the energy range of 20 MeV/nucleon expected from low-energy facilities. We report our efforts to theoretically describe the reaction mechanism of projectile fission following a multinucleon transfer collision at this energy range. Our calculations are mainly based on a two-step approach: the dynamical stage of the collision is described with either the phenomenological Deep-Inelastic Tr...
Abreu, M C; Alexa, C; Arnaldi, R; Ataian, M R; Baglin, C; Baldit, A; Bedjidian, Marc; Beolè, S; Boldea, V; Bordalo, P; Borges, G; Bussière, A; Capelli, L; Castanier, C; Castor, J I; Chaurand, B; Chevrot, I; Cheynis, B; Chiavassa, E; Cicalò, C; Claudino, T; Comets, M P; Constans, N; Constantinescu, S; Cortese, P; De Falco, A; De Marco, N; Dellacasa, G; Devaux, A; Dita, S; Drapier, O; Ducroux, L; Espagnon, B; Fargeix, J; Force, P; Gallio, M; Gavrilov, Yu K; Gerschel, C; Giubellino, P; Golubeva, M B; Gonin, M; Grigorian, A A; Grigorian, S; Grossiord, J Y; Guber, F F; Guichard, A; Gulkanian, H R; Hakobyan, R S; Haroutunian, R; Idzik, M; Jouan, D; Karavitcheva, T L; Kluberg, L; Kurepin, A B; Le Bornec, Y; Lourenço, C; Macciotta, P; MacCormick, M; Marzari-Chiesa, A; Masera, M; Masoni, A; Monteno, M; Musso, A; Petiau, P; Piccotti, A; Pizzi, J R; Prado da Silva, W L; Prino, F; Puddu, G; Quintans, C; Ramello, L; Ramos, S; Rato-Mendes, P; Riccati, L; Romana, A; Santos, H; Saturnini, P; Scalas, E; Scomparin, E; Serci, S; Shahoyan, R; Sigaudo, F; Silva, S; Sitta, M; Sonderegger, P; Tarrago, X; Topilskaya, N S; Usai, G L; Vercellin, Ermanno; Villatte, L; Willis, N
2002-01-01
The charged particle distributions $dN_{ch}/d\\eta$ have been measured by the NA50 experiment in Pb--Pb collisions at the CERN SPS. Measurements have been done at incident energies of 158 and 40 GeV per nucleon over a broad impact parameter range. Results obtained with two independent centrality estimators, namely the neutral transverse energy $E_T$ and the forward energy $E_{ZDC}$, are reported.}
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
Search for few-nucleon correlations in doubly inclusive processes
International Nuclear Information System (INIS)
Strikman, M.I.; Frankfurt, L.L.
1981-01-01
Earlier work showed that the few-nucleon correlation model is useful in calculation of the inclusive production of cumulative particles at high energies. Certain integrated characteristics of doubly inclusive spectra in high-energy processes are investigated and permit direct information to be obtained on the structure of the correlations. Scattering of a high-energy lepton by a light nucleus with production of a cumulative nucleon is studied, with particular attention to the average transverse momentum of the hadrons recorded, and the doubly inclusive cross section averaged over the transverse momenta of the particles emitted in the forward hemisphere. Expressions are obtained for the integrated cross sections
The Mathematical Model High Energy Collisions Process Hadron-Nucleus
International Nuclear Information System (INIS)
Wojciechowski, A.; Strugalska-Gola, E.; Strugalski, Z.
2002-01-01
During the passage high energy hadron by the heavy nucleus emitted are nucleons and many other particles from which most more group are nucleons and mesons π + π - π 0 . in this work we will present the mathematical model which is a simplified description of basic processes in the interior of the nucleus during passing of the hadron by the nucleus. Result of calculations we will compare with experimental results. Experimental data are based on photographs of 180 litre xenon bubble chambers (180 1 KKP) of Institute of Theoretical and Experimental Physics in Moscow (ITEF, Moscow) irradiated with the beam of mesons π - with momentum 3.5 GeV/c. (author)
Recent results in the development of a global medium-energy nucleon-nucleus optical-model potential
International Nuclear Information System (INIS)
Madland, D.G.
1988-02-01
Initial results are presented for the determination of a global medium-energy nucleon-nucleus phenomenological optical-model potential using a relativistic Schroedinger representation. The starting point for this work is the global phenomenological optical-model potential of Schwandt /ital et al./, which is based on measured elastic scattering cross sections and analyzing power for polarized protons ranging from 80 to 180 MeV. This potential is optimally modified to reproduce experimental proton reaction cross sections as a function of energy, while allowing only minimal deterioration in the fits to the elastic cross sections and analyzing powers. Further modifications in the absorptive potential were found necessary to extrapolate the modified potential to higher energies. The final potential is converted to a neutron-nucleus potential by use of standard Lane model assumptions and by accounting approximately for the Coulomb correction. Comparisons of measured and calculated proton reaction and neutron total cross sections are presented for 27 Al, 56 Fe, and 208 Pb. Medium-energy optical-model potentials for complex projectiles are briefly discussed in an appendix. 7 refs., 20 figs
Radial excitations in nucleon-nucleon scattering
International Nuclear Information System (INIS)
Silvestre-Brac, B.; Carbonell, J.; Gignoux, C.
1986-01-01
In the non-relativistic constituent quark model, the role of the radial excitations of the nucleon is studied within a resonating group approach of the nucleon-nucleon scattering. It is shown that, rather than the inclusion of new channels, it is important to include mixed-symmetry spin-isospin components in the nucleon wave function. It is also found that during the collision there is no significant deformation of the nucleon. (orig.)
Medium corrections to nucleon-nucleon interactions
International Nuclear Information System (INIS)
Dortmans, P.J.; Amos, K.
1990-01-01
The Bethe-Goldstone equations have been solved for both negative and positive energies to specify two nucleon G-matrices fully off of the energy shell. Medium correction effects of Pauli blocking and of the auxiliary potential are included in infinite matter systems characterized by fermi momenta in the range 0.5 fm -1 to 1.8 fm -1 . The Paris interaction is used as the starting potential in most calculations. Medium corrections are shown to be very significant over a large range of energies and densities. On the energy shell values of G-matrices vary markedly from those of free two nucleon (NN) t-matrices which have been solved by way of the Lippmann-Schwinger equation. Off of the energy shell, however, the free and medium corrected Kowalski-Noyes f-ratios rate are quite similar suggesting that a useful model of medium corrected G-matrices are appropriately scaled free NN t-matrices. The choice of auxiliary potential form is also shown to play a decisive role in the negative energy regime, especially when the saturation of nuclear matter is considered. 30 refs., 7 tabs., 7 figs
Enhanced emission of high-energy photons perpendicular to the reaction plane in α+Th reactions
International Nuclear Information System (INIS)
Tegner, P.; Marianski, B.; Morsch, H.P.; Rogge, M.; Bargholtz, C.; Decowski, P.; Zemlo, L.
1991-01-01
High-energy photon and neutron emission has been measured in coincidence with fission fragments in α+ 232 Th reactions at 170 MeV. From measurements parallel and perpendicular to the fission plane, anisotropies relative to the reaction plane were determined. The in-plane/out-of-plane intensity ratio is 0.72(7) for photons with energies above 20 MeV and 11(3) for neutrons at 35 MeV. The result for high-energy photons can be explained by nucleon-nucleon bremsstrahlung if the initial flow of nucleons has a correlation to the reaction plane similar to the one observed for fast neutrons
International Nuclear Information System (INIS)
Procureur, S.
2006-07-01
The main goal of the COMPASS experiment at CERN is the determination of the gluon polarisation in the nucleon, V. For this, the helicity asymmetry of the photon gluon fusion process is measured, in the scattering of polarized muons on a polarised deuteron target. This process can be tagged by the production of hadrons with high transverse momentum (pT), that allows to get a large statistics. On the other hand, a physical background remains and complicates the extraction of V. This PhD thesis presents different studies performed to optimize the determination of c in this channel. In particular, a study of the alignment of the 200 detection planes is presented, leading to an improvement of the spectrometer resolution. Performances of the 12 Micromegas detectors have also been determined during 2004 run. Then, the asymmetries obtained in the analysis of 2002 to 2004 data are calculated, for various high PT selections: production of 1 or 2 hadrons, at low or high Q2. An optimization of the selection, based on a neural network, has also been developed, and a detailed study of the experimental false asymmetry has been performed. V extraction is then described, based on Monte Carlo simulations (using PYTHIA or LEPTO). For the first time, the asymmetry of the so-called resolved photon processes is estimated. An improvement on the reconstruction of nucleon momentum fraction carried by the gluon is also proposed, by reconstructing pseudo-jets. Finally, small values obtained for GG are discussed, in terms of constraints on the gluon contribution to the nucleon spin. (author)
International Nuclear Information System (INIS)
Keszenman, D.J.; Sutherland, B.M.
2010-01-01
To determine the linear energy transfer (LET) dependence of the biological effects of densely ionizing radiation in relation to changes in the ionization density along the track, we measured the yields and spectrum of clustered DNA damages induced by charged particles of different atomic number but similar kinetic energy per nucleon in different DNA microenvironments. Yeast DNA embedded in agarose in solutions of different free radical scavenging capacity was irradiated with 1 GeV protons, 1 GeV/nucleon oxygen ions, 980 MeV/nucleon titanium ions or 968 MeV/nucleon iron ions. The frequencies of double-strand breaks (DSBs), abasic sites and oxypurine clusters were quantified. The total DNA damage yields per absorbed dose induced in non-radioquenching solution decreased with LET, with minor variations in radioquenching conditions being detected. However, the total damage yields per particle fluence increased with LET in both conditions, indicating a higher efficiency per particle to induce clustered DNA damages. The yields of DSBs and non-DSB clusters as well as the damage spectra varied with LET and DNA milieu, suggesting the involvement of more than one mechanism in the formation of the different types of clustered damages.
Transverse momentum distributions inside the nucleon from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Musch, Bernhard Ulrich
2009-05-29
Nucleons, i.e., protons and neutrons, are composed of quarks and gluons, whose interactions are described by the theory of quantum chromodynamics (QCD), part of the standard model of particle physics. This work applies lattice QCD to compute quark momentum distributions in the nucleon. The calculations make use of lattice data generated on supercomputers that has already been successfully employed in lattice studies of spatial quark distributions (''nucleon tomography''). In order to be able to analyze transverse momentum dependent parton distribution functions, this thesis explores a novel approach based on non-local operators. One interesting observation is that the transverse momentum dependent density of polarized quarks in a polarized nucleon is visibly deformed. A more elaborate operator geometry is required to enable a quantitative comparison to high energy scattering experiments. First steps in this direction are encouraging. (orig.)
International Nuclear Information System (INIS)
Diddens, A.N.; Van de Walle, R.T.
1981-01-01
An argument is presented for high energy physics from the point of view of the practitioners. Three different angles are presented: The cultural consequence and scientific significance of practising high energy physics, the potential application of the results and the discovery of high energy physics, and the technical spin-offs from the techniques and methods used in high energy physics. (C.F.)
Hard probes of short-range nucleon-nucleon correlations
Energy Technology Data Exchange (ETDEWEB)
J. Arrington, D. W. Higinbotham, G. Rosner, M. Sargsian
2012-10-01
The strong interaction of nucleons at short distances leads to a high-momentum component to the nuclear wave function, associated with short-range correlations between nucleons. These short-range, high-momentum structures in nuclei are one of the least well understood aspects of nuclear matter, relating to strength outside of the typical mean-field approaches to calculating the structure of nuclei. While it is difficult to study these short-range components, significant progress has been made over the last decade in determining how to cleanly isolate short-range correlations in nuclei. We have moved from asking if such structures exist, to mapping out their strength in nuclei and studying their microscopic structure. A combination of several different measurements, made possible by high-luminosity and high-energy accelerators, coupled with an improved understanding of the reaction mechanism issues involved in studying these structures, has led to significant progress, and provided significant new information on the nature of these small, highly-excited structures in nuclei. We review the general issues related to short-range correlations, survey recent experiments aimed at probing these short-range structures, and lay out future possibilities to further these studies.
The origin of mass and experiments on high-energy particle accelerators
International Nuclear Information System (INIS)
Ioffe, B.L.
2006-01-01
The visible world is one consisting of nucleons and electrons. The mass of nucleon arises from chiral symmetry breaking in quantum chromodynamics, so high energy accelerator experiments cannot give a clue to the nature of mass of matter in the visible world. The origin of the mass of the matter will be clarified when the mechanism of chiral symmetry breaking in quantum chromodynamics is established [ru
Final stage of high energy hadron-nucleus nuclear collision reactions
International Nuclear Information System (INIS)
Strugal'ski, Z.; Jedrzejec, H.; Strugalska-Gola, E.; Mulas, E.
1996-01-01
The final or 'slow' stage of the hadron-nucleus collision reactions at high energy is considered on the basis of the collision mechanism prompted experimentally. The transmutation process of the damaged target nucleus into nucleons and stable nuclear fragments is discussed. Relations between intensities or multiplicities n p of the emitted fast protons and the mean intensities or multiplicities b > of the evaporated nucleons and nuclear fragments are presented. 14 refs
International Nuclear Information System (INIS)
Gulamov, K.G.; Navotny, V.Sh.; Uzhinskii, V.V.
1999-01-01
Experimental data on the distributions of fragments with respect to the bound charge (Z bound , Z b3 ) and with respect to the multiplicities and on their correlations are presented. These data are compared with analogous data at 600 MeV per projectile nucleon that were obtained at the ALADIN facility. It has been shown that the processes of gold-nucleus multifragmentation at intermediate and high energies have some common features. At the same time, the multiplicity of medium-mass fragments becomes somewhat less at high energies. Data presented in this study are analyzed within the framework combining the statistical model of nuclear multifragmentation with the Regge model of the breakup of nuclei. This combined model has been shown to reproduce qualitatively the experimental results under discussion. The most pronounced discrepancies have been observed for the yields of doubly charged fragments. The transverse momenta of fragments have been analyzed as functions of the bound charge Z bound . It has been demonstrated that the model underestimates considerably the transverse momenta of fragments. This is interpreted as evidence for a strong radial flow of spectator fragments
Some general scaling rules in high energy heavy ion reactions
International Nuclear Information System (INIS)
Andersson, B.; Idh, J.; Otterlund, I.; Stenlund, E.
1988-09-01
We show, using the Fritiof model scenario that the wide variation in the number of participating nucleons tend to drown other dynamical variations in the measurables of high energy ion collisions. We propose a set if general scaling laws for inclusive distributions in which it is the mean multiplicity and the mean transverse energy from each source which are the measurables in the interactions. (authors)
International Nuclear Information System (INIS)
Margetis, S.
1991-02-01
The interactions of heavy nuclei at ultra relativistic energies is a recently opened field of accelerator physics, not being any longer a rare privilege of cosmic ray experiments. After the first 16 O ions were accelerated at the BNL-AGS (14.5 GeV/nucleon) and the CERN-SPS (200 GeV/nucleon) in 1986 (Sto85), heavier projectiles like 28 Si (BNL) and 32 S (CERN) have been used later on. A large amount of information has been collected with almost every possible detector technique, each of them designed for different physics observables. Some of the experiments were designed to study several different signals from the same event whereas others were dedicated to a specific signal. The experiment NA 35 is an example of a large acceptance, 'multi-particle' experiment. Its aim is a survey study of the reaction mechanisms involved in collisions between heavy nuclei and a search for new phenomena. The calorimetric part of NA 35 is the subject of this study. (orig.) [de
CMB bounds on dark matter annihilation: Nucleon energy losses after recombination
Weniger, C.; Serpico, P.D.; Iocco, F.; Bertone, G.
2013-01-01
We consider the propagation and energy losses of protons and antiprotons produced by dark matter annihilation at redshifts 100
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
High Energy Physics Departments - Overview
International Nuclear Information System (INIS)
Bartke, J.
1999-01-01
Following the tradition, the activities of the seven new units created in 1997 on the basis of the former Department of High Energy Physics are presented under a common header, they are: Department of Particle Theory (Dept 5); Department of Leptonic Interactions (Dept 11); Department of Hadron Structure (Dept 12); Department of High Energy Nuclear Interactions (Dept 13); The ALICE Experiment Laboratory (NAL); The ATLAS Experiment Laboratory (NAT); High Energy Physics Detector Construction Group (PBD). The research covers a variety of problems of the experimental and theoretical high energy particle physics: the hadronic and leptonic interactions with nucleons and nuclei (characteristics of particle production, including heavy quark physics), e + e - interactions and tests of the Standard Model (also radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as the spectra, composition and interactions of high energy cosmic ray particles. Research on detectors and accelerator components as well as the development of the apparatus for the high energy physics experiments at future accelerators: LHC (CERN, Geneva), RHIC (Brookhaven), B-Factory (KEK, Tsukuba) and TESLA (DESY) is also presented. The technology of new materials with unique properties such as carbon-carbon composites is also worked on from the point of view of their application in high energy physics experiments. The Division is located in a separate building on the campus of the University of Mining and Metallurgy (UMM). This location, close to the Jagiellonian University (JU), facilitates the collaboration with the latter and with the UMM. The joint weekly seminars carried out for nearly 40 years prove this long term tradition. A substantial part of the activities is teaching and training students from the academic community in Cracow. Joint research, teaching and academic training in the high energy physics are carried out within the M. Miesowicz
Personal history of nucleon polarization experiments
International Nuclear Information System (INIS)
Chamberlain, O.
1984-09-01
The history of nucleon scattering experiments is reviewed, starting with the observation of large proton polarizations in scattering from light elements such as carbon, and ending with the acceleration of polarized proton beams in high-energy synchrotrons. Special mention is made about significant contributions made by C.L. Oxley, L. Wolfenstein, R.D. Tripp, T. Ypsilantis, A. Abragam, M. Borghini, T. Niinikoski, Froissart, Stora, A.D. Krisch, and L.G. Ratner
Scattering of vector mesons off nucleons
International Nuclear Information System (INIS)
Lutz, M.F.M.; Friman, B.; Wolf, G.
2001-12-01
We construct a relativistic and unitary approach to 'high' energy pion- and photon-nucleon reactions taking the πN, πΔ, ρN, ωN, ηN, K Λ, KΣ final states into account. Our scheme dynamically generates the s- and d-wave nucleon resonances N(1535), N(1650) and N(1520) and isobar resonances Δ(1620) and δ(1700) in terms of quasi-local interaction vertices. The description of photon-induced processes is based on a generalized vector-meson dominance assumption which directly relates the electromagnetic quasi-local 4-point interaction vertices to the corresponding vertices involving the ρ and ω fields. We obtain a satisfactory description of the elastic and inelastic pion- and photon-nucleon scattering data in the channels considered. The resulting s-wave ρ- and ω-nucleon scattering amplitudes are presented. Using these amplitudes we compute the leading density modification of the ρ and ω mass distributions in nuclear matter. We find a repulsive mass shift for the ω meson at small nuclear density but predict considerable strength in resonance-hole like ω-meson modes. Compared to previous calculations our result for the ρ-meson spectral function shows a significantly smaller in-medium effect. This reflects a not too large coupling strength of the N(1520) resonance to the ρN channel. (orig.)
Nucleon Spin Structure: Longitudinal and Transverse
International Nuclear Information System (INIS)
Chen, Jian-Ping
2011-01-01
Inclusive Deep-Inelastic Scattering (DIS) experiments have provided us with the most extensive information on the unpolarized and longitudinal polarized parton (quark and gluon) distributions in the nucleon. It has becoming clear that transverse spin and transverse momentum dependent distributions (TMDs) study are crucial for a more complete understanding of the nucleon structure and the dynamics of the strong interaction. The transverse spin structure and the TMDs are the subject of increasingly intense theoretical and experimental study recently. With a high luminosity electron beam facility, JLab has played a major role in the worldwide effort to study both the longitudinal and transverse spin structure. Highlights of recent results will be presented. With 12-GeV energy upgrade, JLab will provide the most precise measurements in the valence quark region to close a chapter in longitudinal spin study. JLab will also perform a multi-dimensional mapping of the transverse spin structure and TMDs in the valence quark region through Semi-Inclusive DIS (SIDIS) experiments, providing a 3-d partonic picture of the nucleon in momentum space and extracting the u and d quark tensor charges of the nucleon. The precision mapping of TMDs will also allow a detailed study of the quark orbital motion and its dynamics.
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
Hadron dynamics at high energies
International Nuclear Information System (INIS)
Storrow, J.K.
1977-01-01
The nine lectures give a very brief introduction to hadron dynamics at high energies. They concentrate on basic concepts such as Regge poles, duality and geometrical ideas, and simple applications of these ideas to the problem of understanding data. To some extent two body phenomenology is emphasized at the expense of multiparticle final states and when the latter have been considered they have concentrated on inclusive reactions. One lecture discussed data on 2-2 reactions in order to provide the motivation for Regge pole theory, then two lectures are devoted to basic concepts. Then duality is introduced and shown to provide reasonable restrictions on a pole model. A lecture is then devoted to discussing geometrical ideas i.e. the t-dependence of data is looked at from an s-channel point of view. The section on two-body phenomenology is then concluded by discussing applications of the above ideas to two reactions-pion-nucleon scattering and np charge exchange scattering. The remaining three lectures are devoted to multiparticle reactions. Exclusive reactions are considered briefly and then the remainder of the course is concerned with inclusive reactions. The concepts of scaling and limiting fragmentation are discussed and Mueller's generalised optical theorem introduced and then applied in various kinematic limits. (author)
Astrophysical searches for exotic phenomena in ultrahigh energy neutrino-nucleon scattering
International Nuclear Information System (INIS)
Morris, D.A.; Ringwald, A.
1994-03-01
We investigate the potential of near-future neutrino telescopes like NESTOR for searches for exotic processes in ultrahigh energy neutrino-quark scattering. We consider signatures such as muon bundles and/or contained cascades from the nonperturbative production of multiple weak gauge bosons in the Standard Model, compositeness and leptoquark production. (orig.)
Nucleon charge exchange reaction and antiproton elastic scattering at intermediate energies
International Nuclear Information System (INIS)
Kronenfeld, J.
1985-02-01
This work treats the medium energy nuclear (p,n) charge exchange reaction to analog states and the low energy elastic scattering of antiprotons and investigates the central aspects of a microscopic theory based on multiple-scattering series which are pertinent to these reactions. A two-step term of the Distorted Wave Impulse Approximation (DWIA) in treating the (p,n) reaction, was included. For the very absorptive p-bar interaction with nuclei we conjecture that a partial infinite summation, constituing a renormalization of the single scattering term of the optical potential series provides the dominant feature of this interaction. In this work the excitation of analog states is calculated and it was found that the (p,n) reaction is described fairly well by the DWIA. In the first part of the work the (p,n) reaction in the energy range 100-200 MeV was treated. The DWIA calculations were based on eikonalization. In the second part of the work the p-barA interaction with the selfconsistent scheme mentioned above, for scattering energies 30-120 MeV, was examined. (author)
Effects of pairing correlation on nuclear level density parameter and nucleon separation energy
International Nuclear Information System (INIS)
Rajesekaran, T.R.; Selvaraj, S.
2002-01-01
A systematic study of effects of pairing correlations on nuclear level density parameter 'a' and neutron separation energy S N is presented for 152 Gd using statistical theory of nuclei with deformation, collective and noncollective rotational degrees of freedom, shell effects, and pairing correlations
Overview of polarization in intermediate energy nucleon-nucleus inelastic scattering
International Nuclear Information System (INIS)
Carey, T.
1985-01-01
The general role that polarization transfer (PT) can play in the ''dissection'' of medium-energy N-nucleus inelastic reactions is reviewed, specifically concentrating on the importance of complete sets of PT observables for the study of nuclear structure. The discussion is largely in the context of plane-wave impulse approximations, with the effects of distortions considered through comparisons between simple plane-wave predictions and DWIA computations. 31 refs., 11 figs
On single nucleon wave functions in nuclei
International Nuclear Information System (INIS)
Talmi, Igal
2011-01-01
The strong and singular interaction between nucleons, makes the nuclear many body theory very complicated. Still, nuclei exhibit simple and regular features which are simply described by the shell model. Wave functions of individual nucleons may be considered just as model wave functions which bear little resemblance to the real ones. There is, however, experimental evidence for the reality of single nucleon wave functions. There is a simple method of constructing such wave functions for valence nucleons. It is shown that this method can be improved by considering the polarization of the core by the valence nucleon. This gives rise to some rearrangement energy which affects the single valence nucleon energy within the nucleus.
Investigation of nuclear matter properties by means of high energy nucleus-nucleus collisions
International Nuclear Information System (INIS)
Stock, R.
1985-09-01
We review recent advances towards an understanding of high density nuclear matter, as created in central collisions of nuclei at high energy. In particular, information obtained for the nuclear matter equation of state will be discussed. The lectures focus on the Bevalac energy domain of 0.4 to 2 GeV per projectile nucleon. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Chatrchyan, Serguei [Yerevan Physics Inst. (Armenia); et al.
2011-08-01
A measurement is presented of the charged hadron multiplicity in hadronic PbPb collisions, as a function of pseudorapidity and centrality, at a collision energy of 2.76 TeV per nucleon pair. The data sample is collected using the CMS detector and a minimum-bias trigger, with the CMS solenoid off. The number of charged hadrons is measured both by counting the number of reconstructed particle hits and by forming hit doublets of pairs of layers in the pixel detector. The two methods give consistent results. The charged hadron multiplicity density dN(ch)/d eta, evaluated at eta=0 for head-on collisions, is found to be 1612 +/- 55, where the uncertainty is dominated by systematic effects. Comparisons of these results to previous measurements and to various models are also presented.
pp Elastic Scattering at LHC and Nucleon Structure
Islam, M M; Prokudin, A V
2003-01-01
High energy elastic pp differential cross section at LHC at the c.m. energy 14 TeV is predicted using the asymptotic behavior of tot(s) and (s), and the measured p differential cross section at =546 GeV. The phenomenological investigation has progressively led to an effective field theory model that describes the nucleon as a chiral bag embedded in a quark-antiquark condensed ground state. The measurement of pp elastic scattering at LHC up to large |t| 10 GeV2 by the TOTEM group will be crucial to test this structure of the nucleon.
$pp$ Elastic Scattering at LHC and Nucleon Structure
Islam, M M; Prokudin, A V
2003-01-01
High energy elastic pp differential cross section at LHC at the c.m. energy 14 TeV is predicted using the asymptotic behavior of sigma-tot(s) and rho(s), and the measured pbar-p differential cross section at sqrt{s}=546 GeV. The phenomenological investigation has progressively led to an effective field theory model that describes the nucleon as a chiral bag embedded in a quark-antiquark condensed ground state. The measurement of pp elastic scattering at LHC up to large |t| >~ 10 GeV^2 by the TOTEM group will be crucial to test this structure of the nucleon.
International Nuclear Information System (INIS)
Liu Jianye; Xing Yongzhong; Guo Wenjun
2003-01-01
We study the isospin effects of the mean field and two-body collision on the nucleon emissions at the intermediate energy heavy-ion collisions by using an isospin-dependent transport theory. The calculated results show that the nucleon emission number N n depends sensitively on the isospin effect of nucleon-nucleon cross section and weakly on the isospin-dependent mean field for neutron-poor system in higher beam energy region. In particular, the correlation between the medium correction of two-body collision and the momentum-dependent interaction enhances the dependence of nucleon emission number N n on the isospin effect of nucleon-nucleon cross section. On the contrary, the ratio of the neutron-proton ratio of the gas phase to the neutron-proton ratio of the liquid phase, i.e., the degree of isospin fractionation [(N/Z) gas ] b /[(N/Z) liq ] b depends sensitively on the isospin-dependent mean field and weakly on the isospin effect of two-body collision for neutron-rich system in the lower beam energy region. In this case, N n and [(N/Z) gas ] b /[(N/Z) liq ] b are the probes for extracting the information about the isospin-dependent nucleon-nucleon cross section in the medium and the isospin-dependent mean field, respectively
Ciofi degli Atti, Claudio; Morita, Hiko
2017-12-01
Background: The nuclear spectral function is a fundamental quantity that describes the mean-field and short-range correlation dynamics of nucleons embedded in the nuclear medium; its knowledge is a prerequisite for the interpretation of various electroweak scattering processes off nuclear targets aimed at providing fundamental information on strong and weak interactions. Whereas in the case of the three-nucleon and, partly, the four-nucleon systems, the spectral function can be calculated ab initio within a nonrelativistic many-body Schroedinger approach, in the case of complex nuclei only models of the correlated, high-momentum part of the spectral function are available so far. Purpose: The purpose of this paper is to present a new approach such that the spectral function for a specific nucleus can be obtained from a reliable many-body calculation based upon realistic nucleon-nucleon interactions, thus avoiding approximations leading to adjustable parameters. Methods: The expectation value of the nuclear many-body Hamiltonian, containing realistic nucleon-nucleon interaction of the Argonne family, is evaluated variationally by a normalization-conserving linked-cluster expansion and the resulting many-body correlated wave functions are used to calculate the one-nucleon and the two-nucleon momentum distributions; by analyzing the high-momentum behavior of the latter, the spectral function can be expressed in terms of a transparent convolution formula involving the relative and center-of-mass (c.m.) momentum distributions in specific regions of removal energy E and momentum k . Results: It is found that as a consequence of the factorization of the many-body wave functions at short internucleon separations, the high-momentum behavior of the two-nucleon momentum distributions in A =3 ,4 ,12 ,16 ,40 nuclei factorizes, at proper values of the relative and c.m. momenta, into the c.m. and relative momentum distributions, with the latter exhibiting a universal A
The nucleon- nucleon interaction and symmetries
International Nuclear Information System (INIS)
Van Oers, W.T.H.
1992-11-01
With the advent of the possibility to study nucleon-nucleon scattering at medium energies, its extension to investigate fundamental symmetries was recognized early on. It was precisely the introduction of rotational invariance, parity conservation, time reversal invariance, and isotopic spin conversation that led to the description of the N - N scattering matrix in terms of five complex amplitudes: one set of five for proton-proton scattering and one set of five for neutron-proton scattering, or alternatively, one set for the isotopic spin state ι=ο and the other for the isotopic spin state ι=1. Clearly, if one or more of the above constraints are removed, there are additional amplitudes that need to be considered. To be meaningful, experiment requires observables that are particularly sensitive to the violation of a conservation law or symmetry principle. During the last decade a series of precision experiments has been performed to measure charge- symmetry breaking in n - p elastic scattering (corresponding to isotopic spin non-conservation), and to measure parity violation in p-p scattering. For a particle-anti-particle system,like the pp or λλ system one can raise the question of CP violation in a system other than the neutral kaon system may become possible in the near future through pp →λλ and pp→ ≡ ≡. A description is given of the ongoing efforts to measure charge symmetry breaking, parity violation and CP violation.(author). 42 refs., 6 figs
Hard breakup of two nucleons from the 3He nucleus
International Nuclear Information System (INIS)
Sargsian, Misak M.; Granados, Carlos
2009-01-01
We investigate a large angle photodisintegration of two nucleons from the 3 He nucleus within the framework of the hard rescattering model (HRM). In the HRM a quark of one nucleon knocked out by an incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with large relative momentum. Assuming the dominance of the quark-interchange mechanism in a hard nucleon-nucleon scattering, the HRM allows the expression of the amplitude of a two-nucleon breakup reaction through the convolution of photon-quark scattering, NN hard scattering amplitude, and nuclear spectral function, which can be calculated using a nonrelativistic 3 He wave function. The photon-quark scattering amplitude can be explicitly calculated in the high energy regime, whereas for NN scattering one uses the fit of the available experimental data. The HRM predicts several specific features for the hard breakup reaction. First, the cross section will approximately scale as s -11 . Second, the s 11 weighted cross section will have the shape of energy dependence similar to that of s 10 weighted NN elastic scattering cross section. Also one predicts an enhancement of the pp breakup relative to the pn breakup cross section as compared to the results from low energy kinematics. Another result is the prediction of different spectator momentum dependencies of pp and pn breakup cross sections. This is due to the fact that the same-helicity pp-component is strongly suppressed in the ground state wave function of 3 He. Because of this suppression the HRM predicts significantly different asymmetries for the cross section of polarization transfer NN breakup reactions for circularly polarized photons. For the pp breakup this asymmetry is predicted to be zero while for the pn it is close to (2/3).
International Nuclear Information System (INIS)
Richter, B.
1986-03-01
The luminosity and energy requirements are considered for both proton colliders and electron-positron colliders. Some of the basic design equations for high energy linear electron colliders are summarized, as well as design constraints. A few examples are given of parameters for very high energy machines. 4 refs., 6 figs
Counter terms for low momentum nucleon-nucleon interactions
International Nuclear Information System (INIS)
Holt, Jason D.; Kuo, T.T.S.; Brown, G.E.; Bogner, Scott K.
2004-01-01
There is much current interest in treating low energy nuclear physics using the renormalization group (RG) and effective field theory (EFT). Inspired by this RG-EFT approach, we study a low-momentum nucleon-nucleon (NN) interaction, V low-k , obtained by integrating out the fast modes down to the scale Λ∼2 fm -1 . Since NN experiments can only determine the effective interaction in this low momentum region, our chief purpose is to find such an interaction for complex nuclei whose typical momenta lie below this scale. In this paper we find that V low-k can be highly satisfactorily accounted for by the counter terms corresponding to a short range effective interaction. The coefficients C n of the power series expansion ΣC n q n for the counter terms have been accurately determined, and results derived from several meson-exchange NN interaction models are compared. The counter terms are found to be important only for the S, P and D partial waves. Scaling behavior of the counter terms is studied. Finally we discuss the use of these methods for computing shell model matrix elements
Progress report 1986. Laboratory of high energy nuclear physics
International Nuclear Information System (INIS)
1987-01-01
A study of hadron structure using neutrino interactions; high energy photon interactions; a search for gluinos; a spectrometer for the study of quark fusion and structure functions; measurement of the real part of the pp - scattering amplitude at 546 GeV; measurement of photon production in the fragmentation region of pp - interactions at 630 GeV; investigation of very high energy nucleus-nucleus interactions: the quagma; an experience on nucleon stability; as well as high energy nuclear physics research facilities are described [fr
International Nuclear Information System (INIS)
Schuermann, B.; Malfliet, R.; Mies, S.; Zwermann, W.
1984-01-01
Foundations of the transport theory for studying K + , K - , π - and light fragment production in nucleus-nucleus interactions at high energies are given. Inclusive production of protons, K + and π - in the Ne+NaF reaction at 400 MeV and 21 GeV/nucleon is consdered, their differential cross sections are caculated. Differential cross sections of K - and π - production in Si+Si → K + +X and Ne+NaF → π - +X reactions at the energy of 2.1 GeV/nucleon, their energy dependence are estimated. Comparison of the calculated and experimental data is graphically presented. The model of the transport theory is shown to successfully reproduce inclusive spectra of different particles (p, d, π, K + , K - ) in a wide energy range of incident particles (from 400 MeV to 2 GeV/nucleon). This approach can be generalized for lower energies by generating a mean nuclear potentiasl field
High energy neutron radiography
International Nuclear Information System (INIS)
Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.
1996-01-01
High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos
Nucleon-nucleon theory and phenomenology. Progress report and renewal proposal
International Nuclear Information System (INIS)
Signell, P.
1981-01-01
Progress is outlined on five inter-related subprojects: (1) derivation of the intermediate range nucleon-nucleon interaction with the new dramatically altered ππ s-wave interaction and using a new method that utilizes much shorter and simpler analytic continuation through the unphysical region that lies between the πN and ππ physical regions of the N anti N → ππ amplitude (with significantly improved accuracy for the nucleon-nucleon interaction); (2) construction of a short range phenomenological potential that, with the theoretical part mentioned above, gives a precise fit to the nucleon-nucleon data and is parameterized for easy use in nucleon calculations; (3) phase shift analyses of the world data below 400 MeV, especially the large amount of very precise data below 20 MeV and the new data near 55 MeV that have never been analyzed properly, and determining which phases are given by theory at which energies; (4) the introduction of our K-matrix formulation of the Optimal Polynomial Expansion in order to accelerate convergence of the partial wave series at LAMPF energies; and (5) setting up of a cooperatively evaluated and verified permanent nucleon-nucleon data bank in the 0 to 1200 MeV range that can be used by all nucleon-nucleon researchers (or anyone else) via Telenet dial-in and by means of a published compendium
Weisel, G. J.; Tornow, W.; Esterline, J. H.
2015-08-01
We present measurements of n-d analyzing power, {A}y(θ ), at En = 21.0 MeV. The experiment produces neutrons via the 2H(d, n)3He reaction and uses a deuterated liquid-scintillator center detector and six pairs of liquid-scintillator neutron side detectors. Elastic neutron scattering events are identified by using time-of-flight techniques and by setting a gate in the center-detector pulse-height spectrum. Beam polarization is monitored by using a high-pressure helium gas scintillator. The n-d {A}y(θ ) data at 21.0 MeV show a significant discrepancy with the results of rigorous three-body calculations and are consistent with data taken previously by us at 19.0 and 22.5 MeV. We review the overall energy dependence of the three-nucleon analyzing power puzzle in neutron-deuteron elastic scattering, using the best data available. We find that the relative difference between calculations and data is nearly constant at 25% up to En = 22.5 MeV.
The 1989 progress report: High Energy Nuclear Physics
International Nuclear Information System (INIS)
Meyer, J.
1989-01-01
The 1989 progress report of the laboratory of High-Energy Nuclear Physics, of the Polytechnic School (France) is presented. The investigations are performed in the fields of: bosons (W + , W - , Z 0 gauge and Higgs), supersymmetrical particles, new quarks and leptons, quark-gluon plasma, nucleon instability, the neutrino's mass. The 1989 most important event was the LEP start-up. New techniques for accelerating charged particles are studied. The published papers, the conferences and the Laboratory staff are listed [fr
International Nuclear Information System (INIS)
Kuterbekov, K.A.; Zholdybayev, T.K.; Muchamedzhan, A.; Penionzhkevich, Yu.E.; Kukhtina, I.N.
2004-01-01
Full text: The most popular method for join analysis of experimental angular distributions (AD) and total cross sections (TCS) at low and moderate energies is semimicroscopic folding model (SFM) [1]. Since 4 He-particle is a core of exotic nuclei 6,8 He, it is topical to continue systematic investigations at various effective nucleon-nucleon forces. In [2] we investigated for the first time energy and mass dependencies of the parameters SFM at low and moderate energies. At that, as effective forces between nucleons of the colliding nuclei were used total M3Y-interaction [3] and nucleon densities calculated by the method of density functional [4]. In the present work based on SFM there were investigated influences of the density dependence factor in effective nucleon-nucleon forces (4 force options considered) on calculation of ADs and TCSs at interaction of 4 He-particles with stable nuclei (A = 12 - 208) at α-particle energies 21 - 141.5 MeV. Corresponding experimental AD and TCS data used for model verification are of high quality with low error both for angular and energy diapason. Therefore, conclusions made in the performed investigation contain important quantitative information and are valuable for consequent comparative analysis of experimental data on interaction of light exotic nuclei with stable nuclei
International Nuclear Information System (INIS)
Knyaz'kov, O.M.; Kukhtina, I.N.
1989-01-01
The integral characteristics of the potential distribution in nuclei, namely the volume integrals, moments and mean square radii are studied in the framework of the semimicroscopic approach to the interaction of low energy nucleons with nuclei on the base of the exchange nucleon-nucleon correlations and the density dependence of effective forces. The ratio of the normalized multipole moments of potential and matter distributions is investigated. The energy dependence of the integral characteristics is analyzed. 15 refs.; 2 tabs
Temperature and excitation energy of hot nuclei in the reaction of 40Ar+197Au at 25 MeV/nucleon
International Nuclear Information System (INIS)
Wu, H.; Jin, G.; Li, Z.; Dai, G.; Qi, Y.; He, Z.; Luo, Q.; Duan, L.; Wen, W.; Zhang, B.
1997-01-01
The coincidence measurements between heavy fission fragments and light charged particles with Z ≤2 were carried out for the 40 Ar+ 197 Au reaction at 25 MeV/nucleon, to study the properties of hot nuclei in heavy ion induced reactions. The linear momentum transfers (LMTs) were deduced from the folding angle and the time-of-flight difference between two fission fragments of heavy residues. The relationship of the nuclear temperature (slope parameter of the energy spectrum) and the excitation energy was determined independently from the measurement of the kinetic energy spectra in the frames of the emitting sources and from the LMT analysis. Both the temperature and the excitation energy increase with decreasing impact parameter, which suggests that a plateau temperature of 5.5 MeV is reached at an excitation energy of 3.1 MeV/nucleon. The result was also compared with various statistical models that explain the plateau by the multifragmentation process, where the excitation energy is assumed to be stored in compression and expansion effects. (orig.)
New aspects of high energy heavy-ion transfer reactions
International Nuclear Information System (INIS)
Scott, D.K.
1975-03-01
New aspects of heavy ion reactions at incident energies in the region of 10 MeV/nucleon are discussed with an emphasis on the peripheral nature of the collisions, which leads to simplicities in the differential cross sections. The distortion of the peripheral distribution through the interference of direct and multistep processes is used to illustrate aspects of high energy reactions unique to heavy ions. The simplicities of the distributions for reactions on lighter nuclei are exploited to give new information about nuclear structure from direct and compound reactions at high energy. (16 figures, 32 references) (U.S.)
Non-statistical fluctuations in fragmentation of target nuclei in high energy nuclear interactions
Energy Technology Data Exchange (ETDEWEB)
Ghosh, Dipak; Ghosh, Premomoy; Ghosh, Alokananda; Roy, Jaya [Jadavpur Univ., Calcutta (India)
1994-07-01
Analysis of target fragmented ''black'' particles in nuclear emulsion from high energy relativistic interactions initiated by [sup 16]O at 2.1 GeV/nucleon and [sup 12]C and [sup 24]Mg at 4.5 GeV/nucleon reveal the existence of non-statistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. (Author).
Non-statistical fluctuations in fragmentation of target nuclei in high energy nuclear interactions
International Nuclear Information System (INIS)
Ghosh, Dipak; Ghosh, Premomoy; Ghosh, Alokananda; Roy, Jaya
1994-01-01
Analysis of target fragmented ''black'' particles in nuclear emulsion from high energy relativistic interactions initiated by 16 O at 2.1 GeV/nucleon and 12 C and 24 Mg at 4.5 GeV/nucleon reveal the existence of non-statistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. (Author)
NMTC/JAM, Simulates High Energy Nuclear Reactions and Nuclear-Meson Transport Processes
International Nuclear Information System (INIS)
Furihata, Shiori
2002-01-01
1 - Description of program or function: NMTC/JAM is an upgraded version of the code system NMTC/JAERI97. NMTC/JAERI97 simulates high energy nuclear reactions and nucleon-meson transport processes. It implements an intra-nuclear cascade model taking account of the in-medium nuclear effects and the pre-equilibrium calculation model based on the exciton one. For treating the nucleon transport process, the nucleon-nucleus cross sections are revised to those derived by the systematics of Pearlstein. Moreover, the level density parameter derived by Ignatyuk is included as a new option for particle evaporation calculation. A geometry package based on the Combinatorial Geometry with multi-array system and the importance sampling technique is implemented in the code. Tally function is also employed for obtaining such physical quantities as neutron energy spectra, heat deposition and nuclide yield without editing a history file. The code can simulate both the primary spallation reaction and the secondary particle transport in the intermediate energy region from 20 MeV to 3.5 GeV by the use of the Monte Carlo technique. The code has been employed in combination with the neutron-photon transport codes available to the energy region below 20 MeV for neutronics calculation of accelerator-based subcritical reactors, analyses of thick target spallation experimented and so on. 2 - Methods: High energy nuclear reactions induced by incident high energy protons, neutrons and pions are simulated with the Monte Carlo Method by the intra-nuclear nucleon-nucleon reaction probabilities based on an intra-nuclear nucleon cascade model followed by the particle evaporation including high energy fission process. Jet-Aa Microscopic transport model (JAM) is employed to simulate high energy nuclear reactions in the energy range of GeV. All reaction channels are taken into account in the JAM calculation. An intra-nuclear cascade model (ISOBAR code) taking account of the in-medium nuclear effects
Confinement forces in fast backward nucleon production off nuclei
International Nuclear Information System (INIS)
Kopeliovich, B.Z.; Niedermayer, F.
1982-01-01
Multiple colour exchange mechanism is proposed to describe fast backward nucleon production off nuclei at high energies. Cross section of hd → psub(B)X reaction is calculated in the colour flux tube model. This contribution is found to dominate in the hard part of momentum spectra
EXPLORING THE POLARIZATION OF GLUONS IN THE NUCLEON.
Energy Technology Data Exchange (ETDEWEB)
STRATMANN,M.; VOGELSANG,W.
2007-10-22
We give an overview of the current status of investigations of the polarization of gluons in the nucleon. We describe some of the physics of the spin-dependent gluon parton distribution and its phenomenology in high-energy polarized hadronic scattering. We also review the recent experimental results.
International Nuclear Information System (INIS)
Agarwal, R.; Mishra, R.K.; Tiwari, S.; or rm_jbp@yahoo.co.in
2008-01-01
One of the most striking features of solar wind is its organization into high- and low- speed streams. It is now well established that the passage over the Earth of high-speed solar wind streams leads to geomagnetic disturbances. The high-speed plasma streams are thus a key element in the complex chain of events that link geomagnetic activity to the solar activity and are therefore of great interest to the solar terrestrial physics. Two types of high-speed solar wind streams - coronal-hole-associated (or corotating) and flare-generated - were studied based on magnetic field and solar wind plasma parameters. In the work, the dependence was obtained for cosmic ray (CR) depressions due to high-speed solar wind streams during low-amplitude days. The CR nucleonic intensity data were subjected to the superposed epoch analysis with respect to the start time of high-speed solar wind streams. It was found that streams of both types produce significant deviations in the CR intensity during low-amplitude anisotropic wave train events. At the onset of such streams the CR intensity reaches its minimum during low-amplitude events and then increases statistically. (Authors)
International Nuclear Information System (INIS)
Lleres, A.
1988-01-01
Velocity, angular distributions and total cross sections for heavy residues produced in the reactions 12 C, 14 N, 20 Ne, 40 Ar + 124 Sn have been measured in the 10-84 MeV/nucleon incident energy range using catchers technique in association with off-line gamma-activity spectroscopy. The observed reaction products are interpreted as evaporation residues from equilibrated systems formed by complete or incomplete fusion of the projectile and target nuclei. From the velocities and residual masses measured at forward angles, the linear momentum transfers and excitation energies associated with the intermediate systems are estimated using simple fusion-evaporation models and are next compared to the predictions of the preequilibrium and Fermi jets models. Energy, angular, charge and charge correlation distributions for intermediate mass fragments emitted in the reaction 32 S + nat Ag at 30 MeV/nucleon were also measured using gaseous and silicon detectors. The energy and angular distributions indicate that both equilibrated and non-equilibrated emitting sources are present. The equilibrium emission is attributed to the deexcitation of systems produced by incomplete fusion of the projectile and target nuclei. The charge correlation distributions are consistent with an asymmetric fission decay process. The linear momentum transfer and excitation energy associated with the equilibrated source are estimated using a simple fusion-fission model [fr
Plan charge exchange scattering at high energies
International Nuclear Information System (INIS)
Saleem, M.; Bhatti, S.; Fazal-e-Aleem; Rafique, M.
1980-01-01
By a phenomenological choice of the residue functions, a very good fit with experiment for the pion-nucleon charge exchange reaction at Fermilab energies is obtained on a simple Regge-pole model using a quadratic rho trajectory and energy-independent parameters
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.
The axial polarizability of nucleons and nuclei
International Nuclear Information System (INIS)
Ericson, M.; Figureau, A.
1981-02-01
The part of the static nuclear axial polarizability arising from the nucleonic excitations is derived from the low energy expansion of the πN amplitude. It is shown that the contribution of the Δ intermediate state, though dominant, does not saturate the nucleonic response. A similar effect, though more pronounced, is known to occur for the magnetic susceptibility
International Nuclear Information System (INIS)
Johnson, R.C.
1980-01-01
High energy and small momentum transfer 2 'yields' 2 hadronic scattering processes are described in the physical framework of particle exchange. Particle production in high energy collisions is considered with emphasis on the features of inclusive reactions though with some remarks on exclusive processes. (U.K.)
International Nuclear Information System (INIS)
Cesarsky, C.J.
1986-08-01
The galaxy is host to a wide variety of high energy events. I review here recent results on large scale galactic phenomena: cosmic-ray origin and confinement, the connexion to ultra high energy gamma-ray emission from X-ray binaries, gamma ray and synchrotron emission in interstellar space, galactic soft and hard X-ray emission
Energy Technology Data Exchange (ETDEWEB)
EDITED BY M.S. DAVIS
2002-02-01
By the end of this decade, the advancement of current and planned research into the fundamental structure of matter will require a new facility, the Electron Ion Collider (EIC). The EIC will collide high-energy beams of polarized electrons from polarized protons and neutrons, and unpolarized beams of electrons off atomic nuclei with unprecedented intensity. Research at the EIC will lead to a detailed understanding of the structure of the proton, neutron, and atomic nuclei as described by Quantum Chromo-Dynamics (QCD), the accepted theory of the strong interaction. The EIC will establish quantitative answers to important questions by delivering dramatically increased precision over existing and planned experiments and by providing completely new experimental capabilities. Indeed, the EIC will probe QCD in a manner not possible previously. This document presents the scientific case for the design, construction and operation of the EIC. While realization of the EIC requires a significant advance in the development of efficient means of producing powerful beams of energetic electrons, an important consideration for choosing the site of the EIC is the planned upgrade to the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The upgrade planned for RHIC will fully meet the requirements for the ion beam for the EIC, providing a distinct advantage in terms of cost, schedule and the final operation.
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
International Nuclear Information System (INIS)
Bendiscioli, G.; Bressani, T.; Lavezzi, L.; Panzarasa, A.; Salvini, P.
2009-01-01
The dependence of the K + and K - production on the number of nucleons involved in the annihilation process is investigated experimentally in the p-bar annihilation at rest on hydrogen, deuterium, 3 He and 4 He gas targets. Annihilations with any number of prongs (charged pions and kaons, protons and deuterons) are analyzed. Events with and without production of neutral mesons and with and without emission of fast neutrons (that is neutrons involved in the annihilation process) are recognized. The results are consistent with our previous ones on a more restricted sample of annihilation reactions and put in evidence that the strangeness production is lower or higher depending on the reaction channel. As a general trend, the strangeness production is higher in events without neutral mesons and still higher in events with the involvement of a higher number of nucleons. Both K + and K - productions increase with the number of involved nucleons, but K + much more. The maximum K + production is observed in the reaction K + 2π + 2π - 3n on 4 He (with the involvement of 3-4 nucleons); compared with the production on hydrogen in the reaction K + π + 2π - , the production on 4 He is higher by a factor of 31.7±5.5. In the light of some theoretical speculations, this enhancement factor is too high to be explainable in terms of hadronic interactions and could be interpreted as a signature of quark deconfinement and of formation of a quark-gluon plasma
p-wave pion production from nucleon-nucleon collisions
International Nuclear Information System (INIS)
Baru, V.; Epelbaum, E.; Haidenbauer, J.; Hanhart, C.; Kudryavtsev, A. E.; Lensky, V.; Meissner, U.-G.
2009-01-01
We investigate p-wave pion production in nucleon-nucleon collisions up to next-to-next-to-leading order in chiral effective field theory. In particular, we show that it is possible to describe simultaneously the p-wave amplitudes in the pn→ppπ - , pp→pnπ + , pp→dπ + channels by adjusting a single low-energy constant accompanying the short-range operator that is available at this order. This study provides a nontrivial test of the applicability of chiral effective field theory to reactions of the type NN→NNπ.
Inequalities and bounds for nucleon-nucleon scattering
International Nuclear Information System (INIS)
Ramandurai, K.S.
1979-08-01
The objective of this work is to derive model-independent inequalities and bounds for nucleon-nucleon elastic scattering amplitudes based on well-established theoretical principles and symmetries. Two classes of methods are used: algebraic and variational. In the algebraic part, the author derives inequalities and bounds for NN amplitudes and observables using their mutual relations and x symmetries. In the variational part, he employs Lagrange's method of undetermined multipliers to evaluate the bounds. He tests the predictions of a sample of proposed phase shifts at three different energies using the results obtained
The nucleon- nucleon interaction and symmetries
Energy Technology Data Exchange (ETDEWEB)
Van Oers, W T.H.
1992-11-01
With the advent of the possibility to study nucleon-nucleon scattering at medium energies, its extension to investigate fundamental symmetries was recognized early on. It was precisely the introduction of rotational invariance, parity conservation, time reversal invariance, and isotopic spin conversation that led to the description of the N - N scattering matrix in terms of five complex amplitudes: one set of five for proton-proton scattering and one set of five for neutron-proton scattering, or alternatively, one set for the isotopic spin state {iota}={omicron} and the other for the isotopic spin state {iota}=1. Clearly, if one or more of the above constraints are removed, there are additional amplitudes that need to be considered. To be meaningful, experiment requires observables that are particularly sensitive to the violation of a conservation law or symmetry principle. During the last decade a series of precision experiments has been performed to measure charge- symmetry breaking in n - p elastic scattering (corresponding to isotopic spin non-conservation), and to measure parity violation in p-p scattering. For a particle-anti-particle system,like the pp or {lambda}{lambda} system one can raise the question of CP violation in a system other than the neutral kaon system may become possible in the near future through pp {yields}{lambda}{lambda} and pp{yields} {identical_to} {identical_to}. A description is given of the ongoing efforts to measure charge symmetry breaking, parity violation and CP violation.(author). 42 refs., 6 figs.
Multiplicities in high energy interactions
International Nuclear Information System (INIS)
Derrick, M.
1984-01-01
Charged particle multiplicities in hadronic collision have been measured for all energies up to √s = 540 GeV in the center of mass. Similar measurements in e + e - annihilation cover the much smaller range - up to √s = 40 GeV. Data are also available from deep inelastic neutrino scattering up to √s approx. 10 GeV. The experiments measure the mean charged multiplicity , the rapidity density at y = O, and the distributions in prong number. The mean number of photons associated with the events can be used to measure the π 0 and eta 0 multiplicities. Some information is also available on the charged pion, kaon, and nucleon fractions as well as the K 0 and Λ 0 rates and for the higher energy data, the identically equal fraction. We review this data and consider the implications of extrapolations to SSC energies. 13 references
International Nuclear Information System (INIS)
Tezuka, Hirokazu.
1984-10-01
Scattering of a particle by bound nucleons is discussed. Effects of nucleons that are bound in a nucleus are taken as a structure function. The way how to calculate the structure function is given. (author)
International Nuclear Information System (INIS)
Sauer, P.U.
2014-01-01
In this paper, the role of three-nucleon forces in ab initio calculations of nuclear systems is investigated. The difference between genuine and induced many-nucleon forces is emphasized. Induced forces arise in the process of solving the nuclear many-body problem as technical intermediaries toward calculationally converged results. Genuine forces make up the Hamiltonian. They represent the chosen underlying dynamics. The hierarchy of contributions arising from genuine two-, three- and many-nucleon forces is discussed. Signals for the need of the inclusion of genuine three-nucleon forces are studied in nuclear systems, technically best under control, especially in three-nucleon and four-nucleon systems. Genuine three-nucleon forces are important for details in the description of some observables. Their contributions to observables are small on the scale set by two-nucleon forces. (author)
Correlation between observable of four nucleon system in two-body model
International Nuclear Information System (INIS)
Barlette, V.E.
1988-01-01
The four nucleon system with effective nucleon-trinucleon interaction for s waves in states of spin Y = 0 and isospin Y = 0, is studied. The correlations between four nucleon systemn and scattering wavelength, binding energies and, coulomb energy of four nucleons are investigated by N/D method considering only the excited state. (M.C.K.)
International Nuclear Information System (INIS)
Antonov, A.N.; Christov, Chr.V.; Nikolov, E.N.
1989-01-01
Differential cross-section of the 1.04 GeV - proton elastic scattering from 40 Ca is calculated within the Glauber-Sitenko theoretical scheme using the coherent density fluctuation model (CDFM). It is shown that the use of exact noneikonal expression for the two-body scattering amplitude (which describes the p-p data) leads to a satisfactory agreement with the experimental data. The influence of the flucton correlations on the differential cross-sections is considerable as the use of a realistic charge density distribution leads to a better agreement with the experimental data of the CDFM which is not for the case of the independent-particle model. 20 refs.; 4 figs
Nucleon transfer between heavy nuclei
International Nuclear Information System (INIS)
Von Oertzen, W.
1984-02-01
Nucleon transfer reactions between heavy nuclei are characterized by the classical behaviour of the scattering orbits. Thus semiclassical concepts are well suited for the description of these reactions. In the present contribution the characteristics of single and multinucleon transfer reactions at energies below and above the Coulomb barrier are shown for systems like Sn+Sn, Xe+U and Ni+Pb. The role of the pairing interaction in the transfer of nucleon pairs is illustrated. For strong transitions the coupling of channels and the absorption into more complicated channels is taken into account in a coupled channels calculation
Polarized targets in high energy physics
International Nuclear Information System (INIS)
Cates, G.D. Jr.
1994-01-01
Various approaches are discussed for producing polarized nuclear targets for high energy physics experiments. As a unifying theme, examples are drawn from experiments to measure spin dependent structure functions of nucleons in deep inelastic scattering. This single physics goal has, over roughly two decades, been a driving force in advances in target technology. Actual or planned approaches have included solid targets polarized by dynamic nuclear polarization (DNP), several types of internal targets for use in storage rings, and gaseous 3 He targets polarized by spin-exchange optical pumping. This last approach is the type of target adopted for SLAC E-142, an experiment to measure the spin structure function of the neutron, and is described in detail
Polarized targets in high energy physics
Energy Technology Data Exchange (ETDEWEB)
Cates, G.D. Jr. [Princeton Univ., NJ (United States)
1994-12-01
Various approaches are discussed for producing polarized nuclear targets for high energy physics experiments. As a unifying theme, examples are drawn from experiments to measure spin dependent structure functions of nucleons in deep inelastic scattering. This single physics goal has, over roughly two decades, been a driving force in advances in target technology. Actual or planned approaches have included solid targets polarized by dynamic nuclear polarization (DNP), several types of internal targets for use in storage rings, and gaseous {sup 3}He targets polarized by spin-exchange optical pumping. This last approach is the type of target adopted for SLAC E-142, an experiment to measure the spin structure function of the neutron, and is described in detail.
International Nuclear Information System (INIS)
Palmer, R.B.; Gallardo, J.C.
1997-02-01
The authors consider the high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, p anti p), lepton (e + e - , μ + μ - ) and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed
Equilibrium charge state distributions of high energy heavy ions
International Nuclear Information System (INIS)
Clark, R.B.; Grant, I.S.; King, R.; Eastham, D.A.; Joy, T.
1976-01-01
Equilibrium charge state fractions have been measured for N, O, Ne, S, Ar and Kr ions at 1.04 MeV/nucleon after passing through various stripping materials. Further data were obtained at higher energy for S ions (4.12 MeV/nucleon) and Ar ions (4.12 and 9.6 MeV/nucleon). The mean charge fractions can be fitted to universal curves for both solid and gaseous strippers. Measurements of the equilibrium fraction of krypton ions at 1.04 MeV/nucleon passing through heavy vapours have shown that a higher average charge state is obtained than for lighter gaseous strippers. (Auth.)
Nucleon-antinucleon interaction
International Nuclear Information System (INIS)
Dover, C.B.
1983-01-01
The current status of our understanding of the low energy nucleon-antinucleon (N anti N) interaction is reviewed. We compare several phenomenological models which fit the available N anti N cross section data. The more realistic of these models employ an annihilation potential W(r) which is spin, isospin and energy dependent. The microscopic origins for these dependences are discussed in terms of quark rearrangement and annihilation processes. It is argued that the study of N anti N annihilation offers a powerful means of studying quark dynamics at short distances. We also discuss how one may try to isolate coherent meson exchange contributions to the medium and long range part of the N anti N potential. These pieces of the N anti N interaction are calculable via the G-parity transformation from a model for the NN potential; their effects are predicted to be seen in N anti N spin observables, to be measured at LEAR. The possible existence of quasi-stable bound states or resonances of the anti N plus one or more nucleons is discussed, with emphasis on few-body systems. 42 references
International Nuclear Information System (INIS)
Engel, A.R.
1979-01-01
High energy astrophysical research carried out at the Blackett Laboratory, Imperial College, London is reviewed. Work considered includes cosmic ray particle detection, x-ray astronomy, gamma-ray astronomy, gamma and x-ray bursts. (U.K.)
Induced Hyperon-Nucleon-Nucleon Interactions and the Hyperon Puzzle.
Wirth, Roland; Roth, Robert
2016-10-28
We present the first ab initio calculations for p-shell hypernuclei including hyperon-nucleon-nucleon (YNN) contributions induced by a similarity renormalization group transformation of the initial hyperon-nucleon interaction. The transformation including the YNN terms conserves the spectrum of the Hamiltonian while drastically improving model-space convergence of the importance-truncated no-core model, allowing a precise extraction of binding and excitation energies. Results using a hyperon-nucleon interaction at leading order in chiral effective field theory for lower- to mid-p-shell hypernuclei show a good reproduction of experimental excitation energies while hyperon separation energies are typically overestimated. The induced YNN contributions are strongly repulsive and we show that they are related to a decoupling of the Σ hyperons from the hypernuclear system, i.e., a suppression of the Λ-Σ conversion terms in the Hamiltonian. This is linked to the so-called hyperon puzzle in neutron-star physics and provides a basic mechanism for the explanation of strong ΛNN three-baryon forces.
International Nuclear Information System (INIS)
Brown, V.R.
1990-01-01
Nucleon-nucleon bremsstrahlung, NNγ, is a fundamental process, which involves the strong and electromagnetic fields acting simultaneously. Since the electromagnetic interaction is well known, NNγ provides a calculable tool for comparing off-energy-shell effects from different two-nucleon potentials compared to experiment and also provides a simple testing ground, which is sensitive to meson-exchange-current contributions that are so important in electronuclear physics. Historically, experimental studies have focused on ppγ, with only a few measurements of npγ. The present workshop was organized primarily to investigate the interest in, the value of, and the feasibility of doing an npγ experiment using the neutron white source at LANL. An increasing amount of US nuclear physics dollars are being spent on electronuclear physics. npγ is a fundamental process with large meson-exchange currents. In the npγ calculations of Brown and Franklin, the meson-exchange contributions increase the cross section by a factor of roughly two and later the angular distribution of the emitted photon dramatically. The details of these calculated effects have never been verified experimentally, but the proper quantum-mechanical inclusion of meson-exchange contributions, using the methods of brown and Franklin, has proved to be essential in understanding the heavy-ion results. The understanding of the importance of such terms is extremely important inelectronuclear processes, such as are presently under investigation or being planned at Bates, SLAC, and CEBAF. Just one example is in the electrodisintegration of the deuteron, where meson-exchange contributions must be included properly before any conclusions about nuclear models, such as QCD versus meson-exchange potentials can be made
International Nuclear Information System (INIS)
Chen Shengzu
2003-01-01
The technique of High Energy Positron Imaging (HEPI) is the new development and extension of Positron Emission Tomography (PET). It consists of High Energy Collimation Imaging (HECI), Dual Head Coincidence Detection Imaging (DHCDI) and Positron Emission Tomography (PET). We describe the history of the development and the basic principle of the imaging methods of HEPI in details in this paper. Finally, the new technique of the imaging fusion, which combined the anatomical image and the functional image together are also introduced briefly
Compound-nuclear tests of time reversal invariance in the nucleon-nucleon interaction
International Nuclear Information System (INIS)
French, J.B.; Pandey, A.; Smith, J.
1987-01-01
The theory for the effects of time-reversal noninvariance (TRNI) in complex systems is reviewed. Applied to the compound-nuclear data for energy-level, width and cross-section fluctuations (the latter for detailed-balance pairs of reactions proceeding through the compound nucleus) this gives bounds on multiparticle TRNI Hamiltonian matrix elements. Using a fluctuation-free form of statistical spectroscopy the results are reduced to bounds on α, the relative magnitude of the TRNI nucleon-nucleon interaction. The level and width analyses for heavy nuclei gave α ≤ 2 x 10 -3 at high (∼99%) statistical confidence; preliminary calculations for detailed balance with 24 Mg(α,p) 27 Al and its inverse gives α ≤ 4 x 10 -3 at the same high confidence, but ≤0.2 x 10 -3 at 80% confidence. Suggestions are made about experiments which should yield sharper bounds. 28 refs., 1 tab
Multiparticle correlations and intermittency in high energy collisions
Bozek, P
1992-01-01
In this work the analysis of the intermittency signal observed in high energy experi- ments is done using multiparticle distributions and correlation functions. The effect of the dimensional projection of the multiparticle distributions on one or two-dimensional subspace is discussed. The structure of the multiparticle cumulants is analyzed for the DELPHI e + e~ annihilation data. The language of the self-similar distribution func- tions, which is used in this work, is shown to be largely equivalent to the well known a-model. In the case of the ultrarelativistic nuclear collisions, where the Monte-Carlo simulations fail to reproduce the data, we argue that the observed intermittency pattern is a signal of some nonlinear effect beyond the simple superposition of nucleon-nucleon collisions. The model of spatiotemporal intermittency is discussed in details and is shown to reproduce qualitatively the dependence of t...
Bolotnikov, Aleksey E [South Setauket, NY; Camarda, Giuseppe [Farmingville, NY; Cui, Yonggang [Upton, NY; James, Ralph B [Ridge, NY
2011-11-22
The preferred embodiments are directed to a high-energy detector that is electrically shielded using an anode, a cathode, and a conducting shield to substantially reduce or eliminate electrically unshielded area. The anode and the cathode are disposed at opposite ends of the detector and the conducting shield substantially surrounds at least a portion of the longitudinal surface of the detector. The conducting shield extends longitudinally to the anode end of the detector and substantially surrounds at least a portion of the detector. Signals read from one or more of the anode, cathode, and conducting shield can be used to determine the number of electrons that are liberated as a result of high-energy particles impinge on the detector. A correction technique can be implemented to correct for liberated electron that become trapped to improve the energy resolution of the high-energy detectors disclosed herein.
High Energy Physics Departments - Overview
International Nuclear Information System (INIS)
Bartke, J.
2000-01-01
Full text: Following our long-time tradition we will present under a common header the activities of the seven new units created in 1997 on the basis of the former Department of High Energy Physics: Department of Particle Theory (Dept. V); Department of Leptonic Interactions (Dept XI); Department of Hadron Structure (Dept XII); Department of High Energy Nuclear Interactions (Dept XIII); The ALICE Experiment Laboratory (NAL); The ATLAS Experiment Laboratory (NAT); High Energy Physics Detector Construction Group (PBD). At the end we will list our common activities: lectures and courses as well as seminars. Our research covers a variety of problems of the experimental and theoretical high energy particle physics: the hadronic and leptonic interactions with nucleons and nuclei (characteristics of particle production, including heavy quark physics), e + e - interactions and tests of the Standard Model (also evaluation of radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as the spectra, composition and interactions of high energy cosmic ray particles. Research on detectors and accelerator components as well as the development of the apparatus for the high energy physics experiments at future accelerators: LHC (CERN, Geneva), RHIC (Brookhaven), B-Factory (KEK, Tsukuba) and TESLA (DESY, Hamburg) is also carried out. The technology of new materials with unique properties such as carbon-carbon composites is also worked on from the point of view of their application in high energy physics experiments. The Division is located in a separate building on the campus of the University of Mining and Metallurgy. This location, close to the Jagiellonian University, facilitates the collaboration with the latter and with the University of Mining and Metallurgy. The joint weekly seminars carried out for nearly 40 years prove this long term tradition. A substantial part of our activities is teaching and training students from
Transparency in high-energy nuclear collisions
International Nuclear Information System (INIS)
Karol, P.J.
1992-01-01
Problems associated with transparency schemes based on sharp cutoff models are discussed. The soft spheres model of hadron-nucleus and nucleus-nucleus collisions has been used to explore the influence of the realistic nuclear density geometry on transparency. An average nuclear transparency and an average reaction transparency are defined and their dependence on target and projectile dimensions and on the hadron-nucleon collision cross section are described. The results are expected to be valid for projectile energies above several hundred MeV/nucleon through the ultrarelativistic regime. For uniform (hard sphere) nuclear profiles, methods for obtaining effective total transparencies are suggested
International Nuclear Information System (INIS)
Curceanu, C.; Bazzi, M.; Beer, G.; Berucci, C.; Bombelli, L.; Bragadireanu, A.M.; Cargnelli, M.; Clozza, A.; D'Uffizi, A.; Fiorini, C.; Frizzi, T.; Ghio, F.; Guaraldo, C.; Hayano, R.S.; Iliescu, M.; Ishiwatari, T.; Iwasaki, M.; Kienle, P.; Levi Sandri, P.; Longoni, A.
2013-01-01
The DAΦNE electron–positron collider at the Laboratori Nazionali di Frascati of INFN has made available a unique quality low-energy negative kaons “beam”, which is being used to unlock the secrets of the kaon–nucleon/nuclei interactions at low energies by the SIDDHARTA(-2) and the AMADEUS experiments. SIDDHARTA has already performed unprecedented precision measurements of kaonic atoms, and is being presently upgraded, as SIDDHARTA-2, to approach new frontiers. The AMADEUS experiment already started a data taking with a dedicated carbon target, plans to perform in the coming years precision measurements on kaon–nuclei interactions at low-energies, in particular to study the possible formation of kaonic nuclei and the Λ(1405). The two experiments are briefly presented in this paper
Heavy ion reactions at high energies
International Nuclear Information System (INIS)
Jakobsson, Bo.
1977-01-01
A review on heavy ion experiments at energies >0.1GeV/nucleon is presented. Reaction cross-sections, isotope production cross-sections and pion production in nucleus-nucleus collisions are discussed. Some recent models for heavy ion reactions like the abrasion-ablation model, the fireball model and the different shock-wave models are also presented
Double Polarized Neutron-Proton Scattering and Meson-Exchange Nucleon-Nucleon Potential Models
International Nuclear Information System (INIS)
Raichle, B.W.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Walston, J.R.; Tornow, W.; Wilburn, W.S.; Raichle, B.W.; Gould, C.R.; Haase, D.G.; Seely, M.L.; Walston, J.R.; Tornow, W.; Wilburn, W.S.; Penttilae, S.I.; Hoffmann, G.W.
1999-01-01
We report on polarized beam - polarized target measurements of the spin-dependent neutron-proton total cross-section differences in longitudinal and transverse geometries (Δσ L and Δσ T , respectively) between E n =5 and 20MeV. Single-parameter phase-shift analyses were performed to extract the phase-shift mixing parameter var-epsilon 1 , which characterizes the strength of the nucleon-nucleon tensor interaction at low energies. Consistent with the trend of previous determinations at E n =25 and 50MeV, our values for var-epsilon 1 imply a stronger tensor force than predicted by meson-exchange nucleon-nucleon potential models and nucleon-nucleon phase-shift analyses. copyright 1999 The American Physical Society
Emission of high-energy, light particles from intermediate-energy heavy-ion reactions
International Nuclear Information System (INIS)
Ball, J.B.; Auble, R.L.
1982-01-01
One of the early surprises in examining reaction products from heavy ion reactions at 10 MeV/nucleon and above was the large yield of light particles emitted and the high energies to which the spectra of these particles extended. The interpretation of the origin of the high energy light ions has evolved from a picture of projectile excitation and subsequent evaporation to one of pre-equilibrium (or nonequilibrium) emission. The time scale for particle emission has thus moved from one that occurs following the initial collision to one that occurs at the very early stages of the collision. Research at ORNL on this phenomenon is reviewed
International Nuclear Information System (INIS)
Da Rocha, C.A.; Wilets, L.
1997-01-01
Complex mass poles, or ghost poles, are present in the Hartree-Fock solution of the Schwinger-Dyson equation for the nucleon propagator in renormalizable models with Yukawa-type meson-nucleon couplings, as shown many years ago by Brown, Puff and Wilets (BPW). These ghosts violate basic theorems of quantum field theory and their origin is related to the ultraviolet behavior of the model interactions. Recently, Krein et.al, proved that the ghosts disappear when vertex corrections are included in a self-consistent way, softening the interaction sufficiently in the ultraviolet region. In previous studies of πN scattering using ''dressed'' nucleon propagator and bare vertices, did by Nutt and Wilets in the 70's (NW), it was found that if these poles are explicitly included, the value of the isospin-even amplitude A (+) is satisfied within 20% at threshold. The absence of a theoretical explanation for the ghosts and the lack of chiral symmetry in these previous studies led us to re-investigate the subject using the approach of the linear σ-model and study the interplay of low-energy theorems for πN scattering and ghost poles. For bare interaction vertices we find that ghosts are present in this model as well and that the A (+) value is badly described. As a first approach to remove these complex poles, we dress the vertices with phenomenological form factors and a reasonable agreement with experiment is achieved. In order to fix the two cutoff parameters, we use the A (+) value for the chiral limit (m π →0) and the experimental value of the isoscalar scattering length. Finally, we test our model by calculating the phase shifts for the S waves and we find a good agreement at threshold. (orig.)
High energy nuclear collisions: Theory overview
Indian Academy of Sciences (India)
1012 K, were deconfined and existed as a quark gluon plasma (QGP). These ideas can be tested in collisions of nuclei at ultra-relativistic energies. At the relativistic heavy-ion collider (RHIC), nuclei as heavy as gold are accelerated to an energy of 100 GeV per nucleon. A total energy of 40 TeV is available in the collision of.
Deuteron color degrees of freedom and deuteron break-up at high energy
International Nuclear Information System (INIS)
Kobushkin, A.P.
1992-01-01
Deuteron break-up reactions are analysed from a QCD-motivated point of view. Production of a nucleon with hard momentum is considered as a result of high gluon exchange between three quark clusters in hidden-color component of deuteron wave function. It is shown that the model reproduces well the nucleon momentum distribution extracted from (d,p)-reaction at high energy as well as the tensor analysing powers T 20 of this reaction and of the reaction of elastic pd-backward scattering. 19 refs.; 2 figs.; 1 tab. (author)
Δ++ resonance production in multi-nucleon η-12C interactions at the momentum of 40GeV/c
International Nuclear Information System (INIS)
Huseynaliyev, Y.H; Rustamova, A.B; Huseynaliyeva, L.Y.
2012-01-01
Full text : Study of behavior of the characteristics in hadrons-nucleus interactions at high energy as a function of collision centrality. Centrality dependences are studied in relativistic and ultra-relativistic heavy-ion collisions too. In these experiments as a collision centrality the numbers of participant nucleons, the number of binary nucleon collisions and the mean number of projectile-nucleon interactions have been used. An easy option to set centrality is the use of the number of protons emitted in the reactions to consider multi-nucleon processes. By studying the multi-nucleon events in hadrons nucleon and nucleus interactions on a can get useful information about collective phenomena, for example formation of bound states of the resonances in the nucleus. Physics of these processes serves as a bridge that joins the study of mechanisms for the production of high-energy particles and new phases of strongly-interacting nuclear matter. As the characteristics of secondary particles the transverse momentum, cumulative number and kinetic energy dependences in laboratory frame of the R are studied. An invariant mass distribution of ηp pairs is constructed and the indication on occurrence of a Δ + + baryon resonance and relatively high contribution of deep-inelastic processes in multi-nucleon events are received
The 3rd Nordic meeting on high energy reactions in nuclei
International Nuclear Information System (INIS)
Green, A.M.; Kullander, S.
Abstracts of the 31 lectures given at the meeting are presented. Major emphasis was placed on the nucleon-nucleon and nucleon-antinucleon interaction in bound and unbound systems. Four of the ten sessions were devoted to this subject. Two sessions contained lecture and seminars on 'Isobars in nuclei', two were devoted to hadron-nucleus reactions, one to high-energy heavy-ion reactions and one to new developments of experimental tools. This latter session had two talks, one about channeling with GeV particles and the other about the planned low-energy antiproton facility LEAR at CERN. Talks of more general character were 'The experimental programme at the CERN SC', 'Accelerator produced nuclear fuel' and 'The upsilons, a new family of quark-antiquark bound state'. (JIW)
High energy nuclear excitations
International Nuclear Information System (INIS)
Gogny, D.; Decharge, J.
1983-09-01
The main purpose of this talk is to see whether a simple description of the nuclear excitations permits one to characterize some of the high energy structures recently observed. The discussion is based on the linear response to different external fields calculated using the Random Phase Approximation. For those structure in heavy ion collisions at excitation energies above 50 MeV which cannot be explained with such a simple approach, we discuss a possible mechanism for this heavy ion scattering
High energy cosmic ray signature of quark nuggets
Audouze, J.; Schaeffer, R.; Silk, J.
1985-01-01
It has been recently proposed that dark matter in the Universe might consist of nuggets of quarks which populate the nuclear desert between nucleons and neutron star matter. It is further suggested that the Centauro events which could be the signature of particles with atomic mass A approx. 100 and energy E approx. 10 to 15th power eV might also be related to debris produced in the encounter of two neutron stars. A further consequence of the former proposal is examined, and it is shown that the production of relativistic quark nuggets is accompanied by a substantial flux of potentially observable high energy neutrinos.
High energy radiation detector
International Nuclear Information System (INIS)
Vosburgh, K.G.
1975-01-01
The high energy radiation detector described comprises a set of closely spaced wedge reflectors. Each wedge reflector is composed of three sides forming identical isoceles triangles with a common apex and an open base forming an equilateral triangle. The length of one side of the base is less than the thickness of the coat of material sensitive to high energy radiation. The wedge reflectors reflect the light photons spreading to the rear of the coat in such a way that each reflected track is parallel to the incident track of the light photon spreading rearwards. The angle of the three isosceles triangles with a common apex is between 85 and 95 deg. The first main surface of the coat of high energy radiation sensitive material is in contact with the projecting edges of the surface of the wedge reflectors of the reflecting element [fr
Theoretical high energy physics
International Nuclear Information System (INIS)
Lee, T.D.
1991-01-01
This report discusses theoretical research in high energy physics at Columbia University. Some of the research topics discussed are: quantum chromodynamics with dynamical fermions; lattice gauge theory; scattering of neutrinos by photons; atomic physics constraints on the properties of ultralight-ultraweak gauge bosons; black holes; Chern- Simons physics; S-channel theory of superconductivity; charged boson system; gluon-gluon interactions; high energy scattering in the presence of instantons; anyon physics; causality constraints on primordial magnetic manopoles; charged black holes with scalar hair; properties of Chern-Aimona-Higgs solitons; and extended inflationary universe
Restriction of cosmic-ray acceleration, mechanisms by high-energy Be7/Be data
International Nuclear Information System (INIS)
Orth, C.D.; Buffington, A.; Mast, T.S.
1979-01-01
New high-energy cosmic-ray Be data indicate that the ratio Be 7 /Be drops by approximately a factor of two between 200 and 1500 MeV/nucleon. This result may provide a severe constraint for theories of cosmic-ray acceleration
High energy physics at Tufts University. Progress report, July 16, 1985-July 15, 1986
International Nuclear Information System (INIS)
1986-01-01
Experimental projects in high energy physics that are reported include the Soudan-II Nucleon Decay Project, neutrino physics, pion and kaon production of charm and charm-strange states, and multiparticle spectrometer studies at Fermilab. Theoretical efforts include general kinematic description of polarization in scattering processes and spin phenomenology, as well as applications of quantum chromodynamic perturbation theory
Pionic background for nucleon-nucleon observables
International Nuclear Information System (INIS)
Ballot, J.L.; Robilotta, M.R.
1992-01-01
A method is presented that allows the unambiguous definition of the one pion exchange contribution to nucleon-nucleon scattering observables and then use it to determine those waves where values of phase shifts and mixing parameters may be understood as sums of pionic and non-pionic dynamical effects. This helps the assessment of the explicative power of the various existing phenomenological potentials and may eventually lead to ways of discriminating their effectiveness. (author) 16 refs.; 19 figs.; 2 tabs
Energy Technology Data Exchange (ETDEWEB)
Abramov, B. M.; Alexeev, P. N.; Borodin, Yu. A.; Bulychjov, S. A. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation); Gudima, K. K. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Dukhovskoy, I. A.; Krutenkova, A. P., E-mail: anna.krutenkova@itep.ru; Kulikov, V. V.; Martemianov, M. A.; Matsyuk, M. A. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation); Mashnik, S. G. [Los Alamos National Laboratory (United States); Turdakina, E. N.; Khanov, A. I. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation)
2016-09-15
The yields of long-lived nuclear fragments at an angle of 3.5° that originate fromthe fragmentation of carbon ions with an energy of T{sub 0} = 0.6 GeV per nucleon on a berylliumtarget were measured in the FRAGMexperiment at the ITEP TWA heavy-ion accelerator. The momentum spectra of these fragments cover both the fragmentation-maximum region and the cumulative region. The respective differential cross sections change by about five orders of magnitude. The momentum distributions of fragments in the laboratory frame and their kinetic-energy distributions in the rest frame of the fragmenting nucleus are used to test the predictions of four models of ion–ion interactions: BC, INCL++, LAQGSM03.03, and QMD.
International Nuclear Information System (INIS)
Hippchen, T.
1985-12-01
In a first part, nuclear matter calculations have been performed in the Dirac-Brueckner approach using a) a nucleon-nucleon potential of one-boson-exchange (OBE) type and b) a more realistic interaction in which the fictitious σ-exchange of the OBE-model is replaced by explicit 2π- and πρ-exchange diagrams. Both potential models yield the correct empirical binding energy and saturation density. It turns out that the total sum of relativistic effects caused by the emplicit 2 π- and πρ-exchanges is comparable to those due to σ-exchange. In a second part, the nuclear quasiparticle interaction, i.e. the Landau parameters, have been calculated in the central (F), isospin (F'), spin (G) and spin-isospin (G') channel, in an analogous way. Compared to nonrelativistic calculations (including conventional medium corrections like Pauli and dispersion effects), a strong improvement has been found, especially in the F- and G-channel. Finally, the influence of A 1 -exchange is studied, in NN scattering and in nuclear matter. It turns out that, after a suitable and necessary readjustment of some meson parameters, its role is negligibly small. (orig.)
International Nuclear Information System (INIS)
La Tessa, C. . E-mail chiara@nephy.chalmers.se; Sihver, L.; Mancusi, D.; Zeitlin, C.; Miller, J.; Guetersloh, S.; Heilbronn, L.
2007-01-01
We have collected from the literature partial charge-changing cross sections for projectiles with charge 6=< Z=<26, energy ranging from 290 up to 2100 MeV/nucleon and interacting with several targets, in order to investigate weak and strong factorization properties. The same analysis methods as in our previous work have been applied to the data: we have shown that, except for hydrogen targets, weak and strong factorization properties are valid within 5%, thus confirming the results obtained in the first paper [C. La Tessa, et al., Test of weak and strong factorization in nucleus-nucleus collisions at several hundred MeV/nucleon, Nucl. Phys. A, in press]. Factorization parameters have been calculated and, in particular, target factors have been expressed with ad hoc analytical functions which describe the data trend very well. New expressions for weak and strong factorization properties can then be obtained by substituting the target factors with these functions: this formulation partially isolates the dependence of the partial charge-changing cross sections on the target and projectile mass numbers; moreover, fragment factors are the only parameters left in the formulas thus facilitating the future task of interpolating them with appropriate analytical expressions
Theoretical high energy physics
International Nuclear Information System (INIS)
Lee, T.D.
1992-01-01
This progress report discusses research by Columbia University staff in high energy physics. Some of the topics discussed are as follows: lattice gauge theory; quantum chromodynamics; parity doublets; solitons; baryon number violation; black holes; magnetic monopoles; gluon plasma; Chern-Simons theory; and the inflationary universe
International Nuclear Information System (INIS)
Shklorsky, I.S.
1979-01-01
A selected list of articles of accessible recent review articles and conference reports, wherein up-to-date summaries of various topics in the field of high energy astrophysics can be found, is presented. A special report outlines work done in the Soviet Union in this area. (Auth.)
High energy battery. Hochenergiebatterie
Energy Technology Data Exchange (ETDEWEB)
Boehm, H.; Beyermann, G.; Bulling, M.
1992-03-26
In a high energy battery with a large number of individual cells in a housing with a cooling medium flowing through it, it is proposed that the cooling medium should be guided so that it only affects one or both sides of the cells thermally.
International Nuclear Information System (INIS)
Berger, H.; Herr, H.; Linnecar, T.; Millich, A.; Milss, F.; Rubbia, C.; Taylor, C.S.; Meer, S. van der; Zotter, B.
1980-01-01
The group concerned itself with the analysis of cooling systems whose purpose is to maintain the quality of the high energy beams in the SPS in spite of gas scattering, RF noise, magnet ripple and beam-beam interactions. Three types of systems were discussed. The status of these activities is discussed below. (orig.)
Untitled Document [Argonne Logo] [DOE Logo] High Energy Physics Home Division ES&H Personnel Collider Physics Cosmic Frontier Cosmic Frontier Theory & Computing Detector R&D Electronic Design Mechanical Design Neutrino Physics Theoretical Physics Seminars HEP Division Seminar HEP Lunch Seminar HEP
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
2001-01-01
We analyze the electromagnetic form factors of the nucleon to fourth order in relativistic baryon chiral perturbation theory. We employ the recently proposed infrared regularization scheme and show that the convergence of the chiral expansion is improved as compared to the heavy-fermion approach. We also discuss the inclusion of vector mesons and obtain an accurate description of all four-nucleon form factors for momentum transfer squared up to Q{sup 2}{approx_equal}0.4 GeV{sup 2}.
Shielding experiments with high-energy heavy ions for spaceflight applications
International Nuclear Information System (INIS)
Zeitlin, C; Guetersloh, S; Heilbronn, L; Miller, J; Elkhayari, N; Empl, A; LeBourgeois, M; Mayes, B W; Pinsky, L; Christl, M; Kuznetsov, E
2008-01-01
Mitigation of radiation exposures received by astronauts on deep-space missions must be considered in the design of future spacecraft. The galactic cosmic rays (GCR) include high-energy heavy ions, many of which have ranges that exceed the depth of shielding that can be launched in realistic scenarios. Some of these ions are highly ionizing (producing a high dose per particle) and for some biological endpoints are more damaging per unit dose than sparsely ionizing radiation. The principal physical mechanism by which the dose and dose equivalent delivered by these particles can be reduced is nuclear fragmentation, the result of inelastic collisions between nuclei in the hull of the spacecraft and/or other materials. These interactions break the incident ions into lighter, less ionizing and less biologically effective particles. We have previously reported the tests of shielding effectiveness using many materials in a 1 GeV nucleon -1 56 Fe beam, and also reported results using a single polyethylene (CH 2 ) target in a variety of beam ions and energies up to 1 GeV nucleon -1 . An important, but tentative, conclusion of those studies was that the average behavior of heavy ions in the GCR would be better simulated by heavy beams at energies above 1 GeV nucleon -1 . Following up on that work, we report new results using beams of 12 C, 28 Si and 56 Fe, each at three energies, 3, 5 and 10 GeV nucleon -1 , on carbon, polyethylene, aluminium and iron targets
Overview. Department of High Energy Physics. Section 5
International Nuclear Information System (INIS)
Coghen, T.
1995-01-01
The activities of Department of High Energy Physics in 1994 have been presented. They cover a variety of problems of experimental and theoretical high energy elementary particle physics: hadronic and leptonic interactions with nucleons and nuclei (mainly characteristics of particle production , including heavy quark physics), e + e - interactions and tests of the Standard Model (also evaluations of radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as spectra, composition and interactions of high energy cosmic ray particles.Research on detectors and development of apparatus for high energy physics experiments at future accelerators such as LHC or RHIC were also carried out. The short information about personnel employed in the Department, seminars, publication, conferences and reports is also given
Overview. Department of High Energy Physics. Section 5
Energy Technology Data Exchange (ETDEWEB)
Coghen, T. [Institute of Nuclear Physics, Cracow (Poland)
1995-12-31
The activities of Department of High Energy Physics in 1994 have been presented. They cover a variety of problems of experimental and theoretical high energy elementary particle physics: hadronic and leptonic interactions with nucleons and nuclei (mainly characteristics of particle production , including heavy quark physics), e{sup +} e{sup -} interactions and tests of the Standard Model (also evaluations of radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as spectra, composition and interactions of high energy cosmic ray particles.Research on detectors and development of apparatus for high energy physics experiments at future accelerators such as LHC or RHIC were also carried out. The short information about personnel employed in the Department, seminars, publication, conferences and reports is also given.
Overview. Department of High Energy Physics. Section 5
Energy Technology Data Exchange (ETDEWEB)
Coghen, T [Institute of Nuclear Physics, Cracow (Poland)
1996-12-31
The activities of Department of High Energy Physics in 1994 have been presented. They cover a variety of problems of experimental and theoretical high energy elementary particle physics: hadronic and leptonic interactions with nucleons and nuclei (mainly characteristics of particle production , including heavy quark physics), e{sup +} e{sup -} interactions and tests of the Standard Model (also evaluations of radiative corrections), ultrarelativistic heavy ion interactions and search for the quark-gluon plasma, as well as spectra, composition and interactions of high energy cosmic ray particles.Research on detectors and development of apparatus for high energy physics experiments at future accelerators such as LHC or RHIC were also carried out. The short information about personnel employed in the Department, seminars, publication, conferences and reports is also given.
Energy Technology Data Exchange (ETDEWEB)
Burkert, Volker D.
2016-07-25
Recent results of meson photo-production at the existing electron machines with polarized real photon beams and the measurement of polarization observables of the final state baryons have provided high precision data that led to the discovery of new excited nucleon and $\\Delta$ states using multi-channel partial wave analyses procedures. The internal structure of several prominent excited states has been revealed employing meson electroproduction processes. On the theoretical front, lattice QCD is now predicting the baryon spectrum with very similar characteristics as the constituent quark model, and continuum QCD, such as is represented in the Dyson-Schwinger Equations approach and in light front relativistic quark models, describes the non-perturbative behavior of resonance excitations at photon virtuality of $Q^2 > 1.5GeV^2$. In this talk I discuss the need to continue a vigorous program of nucleon spectroscopy and the study of the internal structure of excited states as a way to reveal the effective degrees of freedom underlying the excited states and their dependence on the distance scale probed.
Inclusive break-up reactions of 6Li at an incident energy of 26 MeV/nucleon
International Nuclear Information System (INIS)
Shyam, R.; Machner, H.; Neumann, B.; Rebel, H.; Gils, H.J.; Planeta, R.; Buschmann, J.; Klewe-Nebenius, H.; Zagromski, S.
1982-01-01
Inclusive charged particle spectra were measured from nuclear reactions induced by 156 MeV 6 Li on 40 Ca. At forward angles the spectra exhibit broad break-up distributions centered around the energy corresponding to the beam velocity. The double differential cross sections together with previous results for a 208 Pb target were analyzed in the framework of the DWBA approach to projectile break-up taking into account elastic and inelastic reactions of the break-up fragments. The high energy tails of the background due to preequilibrium emission of complex charged particles were estimated on the basis of the coalescence model. (orig.) [de
Inclusive break-up reactions of 6Li at an incident energy of 26 MeV/nucleon
International Nuclear Information System (INIS)
Neumann, B.; Rebel, H.; Gils, H.J.; Planeta, R.; Buschmann, J.; Klewe-Nebenius, H.; Zagromski, S.; Shyam, R.; Machner, H.
1982-01-01
Inclusive charged particle spectra were measured from nuclear reactions induced by 156 MeV 6 Li on 40 Ca. At forward angles the spectra exhibit broad break-up distributions centered around the energy corresponding to the beam velocity. The double differential cross sections together with previous results for a 208 Pb target were analyzed in the framework of the DWBA approach to projectile break-up taking into account elastic and inelastic reactions of the break-up fragments. The high energy tails of the background due to preequilibrium emission of complex charged particles were estimated on the basis of the coalescence model. (orig.)
Mean free path of nucleons in a Fermi gas at finite temperature
International Nuclear Information System (INIS)
Collins, M.T.; Griffin, J.J.
1980-01-01
The mean free path of a nucleon in a nuclear Fermi gas at finite temperature is calculated by utilizing the free nucleon-nucleon cross section modified to suppress final states excluded by the Pauli principle. The results agree with an earlier zero-temperature calculation but yield substantially smaller values than a previous finite-temperature analysis. The Fermi gas mean free paths are some two to four times shorter than those implied by phenomenological imaginary optical potentials, suggesting that the present Fermi gas model fails to adequately describe the physical processes determining the mean free path. Even so, the present results, taken as lower bounds on te mean free path, require temperatures of some 4.5 MeV before the mean free path of bound nucleons becomes as short as the nuclear diameter. It follows that very high excitation energies are prerequisite to any short mean free path assumption in nuclear heavy-ion collisions. (orig.)
Percolation Model of Nuclear Multifragmentation in High Energy Nucleus-Nucleus Interactions
International Nuclear Information System (INIS)
Abdel-Waged, Kh.
1994-01-01
A hybrid model based on Reggeon theory inspired model of nuclear distribution, which was successful in explaining the cascading of particles in high energy nucleus-nucleus interactions, and percolation model is proposed. In the framework of this model the yield of the fragment in p + Ag, Au at 350 GeV and C + Ag, Au at 3.6 GeV/nucleon as well as the charge distribution of fragments in Kr, Xe and U interactions with emulsion at ∼ 1 GeV/nucleon is correctly described. 32 refs., 3 figs
Theoretical High Energy Physics
Energy Technology Data Exchange (ETDEWEB)
Christ, Norman H.; Weinberg, Erick J.
2014-07-14
we provide reports from each of the six faculty supported by the Department of Energy High Energy Physics Theory grant at Columbia University. Each is followed by a bibliography of the references cited. A complete list of all of the publications in the 12/1/2010-04/30/2014 period resulting from research supported by this grant is provided in the following section. The final section lists the Ph.D. dissertations based on research supported by the grant that were submitted during this period.
International Nuclear Information System (INIS)
Ruhm, W.
2010-01-01
Full text: Currently, quantification of doses from high-energy radiation fields is a topical issue. This is so because high-energy neutrons play an important role for radiation exposure of air crew members and personnel outside the shielding of ion therapy facilities. In an effort to study air crew exposure from cosmic radiation in detail, two Bonner Sphere Spectrometers (BSSs) have recently been installed to measure secondary neutrons from cosmic radiation, one at the environmental research station 'Schneefernerhaus' at an altitude of 2650 m on the Zugspitze mountain, Germany, the other at the Koldewey station close to the North Pole on Spitsbergen. Based on the measured neutron fluence distributions and on fluence-to-dose conversion coefficients, mean ambient dose equivalent rate values of 75.0 ± 2.9 nSv/h and 8.7 ± 0.6 nSv/h were obtained for October 2008, respectively. Neutrons with energies above about 20 MeV contribute about 50% to dose, at 2650 m. Ambient dose equivalent rates measured by means of a standard rem counter and an extended rem counter at the Schneefernerhaus confirm this result. In order to study the response of state-of-the-art radiation instrumentation in such a high-energy radiation field, a benchmark exercise that included both measurements in and simulation of the stray neutron radiation field at the high-energy particle accelerator at GSI, Germany, were performed. This CONRAD (COordinated Network for RAdiation Dosimetry) project was funded by the European Commission, and the organizational framework was provided by the European Radiation Dosimetry Group, EURADOS. The Monte Carlo simulations of the radiation field and the experimental determination of the neutron spectra with various Bonner Sphere Spectrometers suggest the neutron fluence distributions to be very similar to those of secondary neutrons from cosmic radiation. The results of this intercomparison exercise in terms of ambient dose equivalent are also discussed
Chiral perturbation theory with nucleons
International Nuclear Information System (INIS)
Meissner, U.G.
1991-09-01
I review the constraints posed on the interactions of pions, nucleons and photons by the spontaneously broken chiral symmetry of QCD. The framework to perform these calculations, chiral perturbation theory, is briefly discussed in the meson sector. The method is a simultaneous expansion of the Greens functions in powers of external moments and quark masses around the massless case, the chiral limit. To perform this expansion, use is made of a phenomenological Lagrangian which encodes the Ward-identities and pertinent symmetries of QCD. The concept of chiral power counting is introduced. The main part of the lectures of consists in describing how to include baryons (nucleons) and how the chiral structure is modified by the fact that the nucleon mass in the chiral limit does not vanish. Particular emphasis is put on working out applications to show the strengths and limitations of the methods. Some processes which are discussed are threshold photopion production, low-energy compton scattering off nucleons, πN scattering and the σ-term. The implications of the broken chiral symmetry on the nuclear forces are briefly described. An alternative approach, in which the baryons are treated as very heavy fields, is touched upon
International Nuclear Information System (INIS)
Arbuzov, B.A.
1977-01-01
Described are modern views on the particle structure and particle interactions at high energies. According to the latest data recieved, all particles can be classified in three groups: 1) strong interacting hadrons; 2) leptons, having no strong interactions; 3) photon. The particle structure is described in a quark model, and with the use of gluons. The elementary particle theory is based on the quantum field theory. The energy increase of interacting particles enables to check the main theory principles, such as conventions for causality, relativistic invariance and unitarity. Investigations of weak interactions are of great importance. The progress in this field is connected with unified gauge theories of weak and electromagnetic interactions. For weak interactions promissing are the experiments with colliding electron-proton rings. The new data, especially at higher energies, will lead to a further refinement of the nature of particles and their interactions
Estimation of nuclear destruction in high energy nucleus-nucleus interactions
International Nuclear Information System (INIS)
Uzhinskij, V.V.
1995-01-01
It is assumed that: 1) a projectile particle invokes into target nucleus a cascade of quark-gluon exchanges; 2) the nucleons involved in the cascade are ejected from the nucleus which leads to the nuclear destruction. On these bases a simple model to estimate the nuclear destruction at the fast stage of the interaction is proposed. The allowed region of the model parameters is determined at the proton-emulsion high-energy interaction data analysis: an analysis of gold interactions with nuclei at an energy of 600 MeV/nucleon fixes the parameter values. The distributions on the energy in zero degree calorimeter (T ZDC ) in the interactions of Si+Al, Cu, Pb (14 GeV/nucleon) and Au+Au (10 GeV/nucleon) calculated in the framework of the model and in the cascade-evaporation model (CEM) are presented. The proposed model describes the nuclear destruction at intermediate and high energies better than CEM does. The estimation of the average values of impact parameter and the number of intra-nuclear collisions for Au+Au interactions in the events with different T ZDC is given. 34 refs., 11 figs
International Nuclear Information System (INIS)
Ftacnik, J.; Lichard, P.
1989-01-01
We present a set of semiquantitative predictions for the behaviour of J/ψ suppression in heavy ion collisions as a function of the total transverse energy, nucleon numbers of colliding ions and the J/ψ transverse momentum. These predictions are based on the assumption that all of J/ψ suppression is due to J/ψ and χ disintegrations in collisions with hadrons in a dense hadronic gas formed in the heavy ion collisions. The hydrodynamic evolution of the hadron gas is taken into account. The onset of the quark-gluon plasma formation should manifest itself by clear qualitative deviations from J/ψ suppression calculated in this way, in particular as thresholds or kinks in the E T -dependence, or as a threshold for J/ψ suppression as a function of the atomic number of the target, expected at Cu or below. (orig.)
High energy medical accelerators
International Nuclear Information System (INIS)
Mandrillon, P.
1990-01-01
The treatment of tumours with charged particles, ranging from protons to 'light ions' (carbon, oxygen, neon), has many advantages, but up to now has been little used because of the absence of facilities. After the successful pioneering work carried out with accelerators built for physics research, machines dedicated to this new radiotherapy are planned or already in construction. These high energy medical accelerators are presented in this paper. (author) 15 refs.; 14 figs.; 8 tabs
Theoretical high energy physics
International Nuclear Information System (INIS)
Lee, T.D.
1990-05-01
This report discusses progress on theoretical high energy physics at Columbia University in New York City. Some of the topics covered are: Chern-Simons gauge field theories; dynamical fermion QCD calculations; lattice gauge theory; the standard model of weak and electromagnetic interactions; Boson-fermion model of cuprate superconductors; S-channel theory of superconductivity and axial anomaly and its relation to spin in the parton model
The nucleon-nucleon interaction in the framework of the boson exchange model
International Nuclear Information System (INIS)
Niephaus, G.H.
1984-01-01
The aim of this thesis was the description of the nucleon-nucleon interaction in a microscopically founded model. For this the description of the 2-nucleon problem by an interacting 2-nucleon-pion system was presented. The starting point of our description was a relativistic eigenvalue equation for the system of mesons and two baryons. The interaction of the baryons with the mesons was described by interaction Hamiltonians. By the elimination of antinucleon states by means of a unitary tansformation (Foldy-Wouthuysen transformation) the interaction Hamiltonians for nucleons could be generated for the field-theoretical Lagrangian densities. The Hamiltonians for resonant baryon states were obtained by means of a simplified procedure from the corresponding Lagrangian densities. Because the determination of Lagrangian densities is not unique, for the pion-nucleon coupling two alternative Lagrangian densities were allowed. For the interaction of positive-energy nucleonic states these two coupling yield nearly equal results; the production or annihilation of negative-energy nucleon states (antiparticles) the predictions however are very different. (orig./HSI) [de
International Nuclear Information System (INIS)
Richter, B.
1985-05-01
The conclusions are relatively simple, but represent a considerable challenge to the machine builder. High luminosity is essential. We may in the future discover some new kind of high cross section physics, but all we know now indicates that the luminosity has to increase as the square of the center of mass energy. A reasonable luminosity to scale from for electron machines would be 10 33 cm -2 s -1 at a center of mass energy of 3 TeV. The required emittances in very high energy machines are small. It will be a real challenge to produce these small emittances and to maintain them during acceleration. The small emittances probably make acceleration by laser techniques easier, if such techniques will be practical at all. The beam spot sizes are very small indeed. It will be a challenge to design beam transport systems with the necessary freedom from aberration required for these small spot sizes. It would of course help if the beta functions at the collision points could be reduced. Beam power will be large - to paraphrase the old saying, ''power is money'' - and efficient acceleration systems will be required
Stripping of 1.04 MeV per nucleon krypton ions in high molecular weight vapours
International Nuclear Information System (INIS)
Eastham, D.A.; Joy, T.; Clark, R.B.; King, R.
1976-01-01
Equilibrium charge state distributions have been measured for 1.04 MeV per nucleon krypton ions in heavy vapours with molecular weights from 462 to 6500. Non-equilibrium data are presented for the heaviest vapour. A maximum increase of 0.8 in the mean charge is found relative to a conventional diatomic gas but the pressures required are two orders of magnitude less. (Auth.)
International Nuclear Information System (INIS)
Raman, S.; Kahane, S.; Bhatt, K.H.
1999-01-01
Ever since the pioneering work of Elliott (Elliott J P 1958 London Series A 245 128, 562), quadrupole collectivity in deformed nuclei has been economically described in terms of SU 3 symmetry. Microscopic SU 3 symmetry is not present in the deformed intrinsic states of n nucleons in the abnormal-parity single-particle states j a . However, such (j a ) n states do possess some SU 3 -symmetry-like properties as shown in this work. (author)
Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
Ageev, E S; Alexandrov, Yu A; Alexeev, G D; Amoroso, A; Badelek, B; Balestra, F; Ball, J; Baum, G; Bedfer, Y; Berglund, P; Bernet, C; Bertini, R; Birsa, R; Bisplinghoff, J; Bordalo, P; Bradamante, Franco; Bravar, A; Bressan, A; Brona, G; Burtin, E; Bussa, M P; Bychkov, V N; Cerini, L; Chapiro, A; Cicuttin, A; Colantoni, M L; Colavita, A A; Costa, S; Crespo, M L; Dalla Torre, S; Das-Gupta, S S; Dedek, N; De Masi, R; Denisov, O Yu; Dhara, L; Díaz, V; Dinkelbach, A M; Dolgopolov, A V; Donskov, S V; Dorofeev, V A; Doshita, N; Duic, V; Dünnweber, W; Ehlers, J; Eversheim, P D; Eyrich, W; Fabro, M; Faessler, Martin A; Falaleev, V; Fauland, P; Ferrero, A; Ferrero, L; Finger, Miroslav H; Finger, M Jr; Fischer, H; Franz, J; Friedrich, J M; Frolov, V; Garfagnini, R; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S G; Geyer, R; Giorgi, M; Gobbo, B; Görtz, S; Gorin, A M; Grajek, O A; Grasso, A; Grube, B; Grünemaier, A; Hannappel, J; Von Harrach, D; Hasegawa, T; Hedicke, S; Heinsius, F H; Hermann, R; Hess, C; Hinterberger, F; Von Hodenberg, M; Horikawa, N; Horikawa, S; D'Hose, N; Ijaduola, R B; Ilgner, C; Ioukaev, A I; Ishimoto, S; Ivanov, O; Iwata, T; Jahn, R; Janata, A; Joosten, R; Jouravlev, N I; Kabuss, E M; Kalinnikov, V; Kang, D; Karstens, F; Kastaun, W; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Khomutov, N V; Kisselev, Yu V; Klein, F; Koblitz, S; Koivuniemi, J H; Kolosov, V N; Komissarov, E V; Kondo, K; Königsmann, K C; Konoplyannikov, A K; Konorov, I; Konstantinov, V F; Korentchenko, A S; Korzenev, A; Kotzinian, A M; Koutchinski, N A; Kowalik, K L; Kravchuk, N P; Krivokhizhin, V G; Krumshtein, Z; Kühn, R; Kunne, Fabienne; Kurek, K; Ladygin, M E; Lamanna, M; Leberig, M; Le Goff, J M; Lichtenstadt, J; Liska, T; Ludwig, I; Maggiora, A; Maggiora, M; Magnon, A; Mallot, G K; Manuilov, I V; Marchand, C; Marroncle, J; Martin, A; Marzec, J; Matsuda, T; Maksimov, A N; Medved, K S; Meyer, W; Mielech, A; Mikhailov, Yu V; Moinester, M A; Nahle, O; Nassalski, J P; Neliba, S; Neyret, D P; Nikolaenko, V I; Nozdrin, A A; Obraztsov, V F; Olshevskii, A G; Ostrick, M; Padee, A; Pagano, P; Panebianco, S; Panzieri, D; Paul, S; Pereira, H D; Peshekhonov, V D; Piragino, G; Platchkov, S; Platzer, K; Pochodzalla, J; Polyakov, V A; Popov, A A; Pretz, J; Procureur, S; Quintans, C; Ramos, S; Rebourgeard, P C; Reicherz, G; Reymann, J; Rith, K; Rondio, Ewa; Rozhdestvensky, A M; Sadovski, A B; Saller, E; Samoylenko, V D; Sandacz, A; Sans, M; Sapozhnikov, M G; Savin, I A; Schiavon, Paolo; Schill, C; Schmidt, T; Schmitt, H; Schmitt, L; Shevchenko, O Yu; Shishkin, A A; Siebert, H W; Sinha, L; Sissakian, A N; Skachkova, A N; Slunecka, M; Smirnov, G I; Sozzi, F; Srnka, A; Stinzing, F; Stolarski, M; Sugonyaev, V P; Sulc, M; Sulej, R; Takabayashi, N; Tchalishev, V V; Tessarotto, F; Teufel, A; Thers, D; Tkatchev, L G; Toeda, T; Tretyak, V I; Trousov, S; Varanda, M; Virius, M; Vlassov, N V; Wagner, M; Webb, R; Weise, E; Weitzel, Q; Wiedner, U; Wiesmann, M; Windmolders, R; Wirth, S; Wislicki, W; Zanetti, A M; Zaremba, K; Zhao, J; Ziegler, R; Zvyagin, A
2006-01-01
We present a determination of the gluon polarization Delta G/G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q^2 = 0.002 +- 0.019(stat.) +- 0.003(syst.). From this value, we obtain in a leading-order QCD analysis Delta G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3 (GeV}/c)^2.
Instrumentation for continuous monitoring of low energy cosmic ray intensity
Energy Technology Data Exchange (ETDEWEB)
Kumar, S; Prasad, R; Yadav, R S [Aligarh Muslim Univ. (India). Dept. of Physics; Naqvi, T H [Z.H. Engineering Coll., Aligarh (India); Ahmed, Rais [National Council of Educational Research and Training, New Delhi (India)
1975-12-01
A high counting rate neutron monitor developed at Aligarh for continuous monitoring of low energy nucleonic component of cosmic rays is described. Transistorized electronic circuits used are described.
High energy particle transport code NMTC/JAM
International Nuclear Information System (INIS)
Niita, Koji; Meigo, Shin-ichiro; Takada, Hiroshi; Ikeda, Yujiro
2001-03-01
We have developed a high energy particle transport code NMTC/JAM, which is an upgraded version of NMTC/JAERI97. The applicable energy range of NMTC/JAM is extended in principle up to 200 GeV for nucleons and mesons by introducing the high energy nuclear reaction code JAM for the intra-nuclear cascade part. For the evaporation and fission process, we have also implemented a new model, GEM, by which the light nucleus production from the excited residual nucleus can be described. According to the extension of the applicable energy, we have upgraded the nucleon-nucleus non-elastic, elastic and differential elastic cross section data by employing new systematics. In addition, the particle transport in a magnetic field has been implemented for the beam transport calculations. In this upgrade, some new tally functions are added and the format of input of data has been improved very much in a user friendly manner. Due to the implementation of these new calculation functions and utilities, consequently, NMTC/JAM enables us to carry out reliable neutronics study of a large scale target system with complex geometry more accurately and easily than before. This report serves as a user manual of the code. (author)
Conflicting coupling of unpaired nucleons in odd-odd nuclei
International Nuclear Information System (INIS)
Volkov, D.A.; Levon, A.I.
1990-01-01
Phenomenological approach is described, using it, energy spectra of odd-odd nucleus collective bands based on conflicting state of unpaired nucleons can be calculated. It is ascertained that in a conflicting bond unpaired nucleon acts as a spectator, i.e. energy spectra of collective bands in odd-odd nuclei are similar to the spectra of collective bands in heighbouring odd nuclei, which are based on the state of a strongly bound nucleon is included in the conflicting configuration
Diquark fragmentation functions in hadron-nucleon interactions at 19 GeV/c and other energies
International Nuclear Information System (INIS)
Bakken, V.; Breivik, F.O.; Jacobsen, T.
New data on pion production in pn-interactions at 19 GeV/c are used, together with earlier data on pion production in pn (π + n) at other energies, to determine the diquark fragmentation functions Dsup(π) +- sub(dd)(=Dsup(π) +- sub(uu)) and Dsup(π)sub(ud) in the neutron and proton fragmentation regions. Typical high energy data on pion production in pp-interactions are also considered. The unfavoured fragmentation function Dsup(π) + sub(dd)(x) is found to be much smaller than the favoured fragmentati ion function Dsup(π) - sub(dd)(x) and to have a steeper x-dependence. The diquark fragmentation functions agree very well with those from v(v - )- proton interactions as expected from quark parton models
Energy Technology Data Exchange (ETDEWEB)
Dobretsov, Yu; Dolgoshein, B; Kirillov-Ugryumov, V
1980-12-01
The properties and formation are described of ..mu..-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of ..mu..-nucleon atoms is shown. The prospects of their use are indicated.
International Nuclear Information System (INIS)
Dobretsov, Yu.; Dolgoshejn, B.; Kirillov-Ugryumov, V.
1980-01-01
The properties and formation are described of μ-nucleon atoms, the Larmor method of muon spin precession is discussed and the experimental confirmation of the existence of μ-nucleon atoms is shown. The prospects of their use are indicated. (J.P.)
Nucleon-nucleon scattering phase shifts
International Nuclear Information System (INIS)
Bryan, R.
1978-01-01
Here are presented 0 to 800 MeV nucleon-nucleon elastic and inelastic phase parameters derived by several groups: Arndt and Roper; Hoshizaki; Bugg; Bystricky, Lechanoine, and Lehar; and Bryan, Clark, and VerWest. Resonant-like behavior appears in the 1 D 2 and 3 F 3 states above the inelastic threshold in Hoshizaki's analysis but not in Arndt and Roper's. The np data are inadequate to permit determination of the I = O phase parameters above 600 MeV. 27 references
Theoretical high energy physics
International Nuclear Information System (INIS)
Lee, T.D.
1993-01-01
Brief reports are given on the work of several professors. The following areas are included: quantum chromodynamics calculations using numerical lattice gauge theory and a high-speed parallel computer; the ''spin wave'' description of bosonic particles moving on a lattice with same-site exclusion; a high-temperature expansion to 13th order for the O(4)-symmetric φ 4 model on a four-dimensional F 4 lattice; spin waves and lattice bosons; superconductivity of C 60 ; meson-meson interferometry in heavy-ion collisions; baryon number violation in the Standard Model in high-energy collisions; hard thermal loops in QCD; electromagnetic interactions of anyons; the relation between Bose-Einstein and BCS condensations; Euclidean wormholes with topology S 1 x S 2 x R; vacuum decay and symmetry breaking by radiative corrections; inflationary solutions to the cosmological horizon and flatness problems; and magnetically charged black holes
High frequency energy measurements
International Nuclear Information System (INIS)
Stotlar, S.C.
1981-01-01
High-frequency (> 100 MHz) energy measurements present special problems to the experimenter. Environment or available electronics often limit the applicability of a given detector type. The physical properties of many detectors are frequency dependent and in some cases, the physical effect employed can be frequency dependent. State-of-the-art measurements generally involve a detection scheme in association with high-speed electronics and a method of data recording. Events can be single or repetitive shot requiring real time, sampling, or digitizing data recording. Potential modification of the pulse by the detector and the associated electronics should not be overlooked. This presentation will review typical applications, methods of choosing a detector, and high-speed detectors. Special considerations and limitations of some applications and devices will be described
International Nuclear Information System (INIS)
Holben, B.C.; Bach, R.E.
1975-01-01
A nucleonic measuring instrument is described wherein a housing contains a radiation source and has an aperture controlled by a shutter which is spring loaded to a closed position for confining and shielding the radiation and is movable by a motor to an open position for releasing the radiation, the motor being supplied with power through a heat sensitive element so that it is deenergized and the shutter closes in response to a predetermined high ambient temperature such as may be caused by a fire, and including an explosive blank cartridge positioned in relation to the shutter guide which explodes in response to a still higher ambient temperature, deforming the guide and thereby locking the shutter in the closed position. (auth)
Nucleon Electromagnetic Form Factors
Energy Technology Data Exchange (ETDEWEB)
Marc Vanderhaeghen; Charles Perdrisat; Vina Punjabi
2007-10-01
There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has greatly improved by performing double polarization experiments, in comparison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at JLab, MAMI, and MIT-Bates. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed, including the recent progress in the determination of the valence quark generalized parton distributions of the nucleon, as well as the steady rate of improvements made in the lattice QCD calculations.
Cosmic Ray Deuterium from 0.2 to 3.0 GeV/nucleon
DEFF Research Database (Denmark)
Davis, A.J.; Labrador, A.W.; Mewaldt, R.A.
1996-01-01
The abundances of cosmic ray protons and deuterium between 0.2 and 3.0 GeV/nucleon were measured by the IMAX balloon--borne magnet spectrometer during a flight in July, 1992. These isotope measurements extend to significantly higher energies than have previously been achieved. A high--resolution ......The abundances of cosmic ray protons and deuterium between 0.2 and 3.0 GeV/nucleon were measured by the IMAX balloon--borne magnet spectrometer during a flight in July, 1992. These isotope measurements extend to significantly higher energies than have previously been achieved. A high...
A novel nuclear dependence of nucleon–nucleon short-range correlations
Energy Technology Data Exchange (ETDEWEB)
Dai, Hongkai [College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070 (China); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Rong, E-mail: rwang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Lanzhou University, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Huang, Yin [Lanzhou University, Lanzhou 730000 (China); Chen, Xurong [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)
2017-06-10
A linear correlation is found between the magnitude of nucleon–nucleon short-range correlations and the nuclear binding energy per nucleon with pairing energy removed. By using this relation, the strengths of nucleon–nucleon short-range correlations of some unmeasured nuclei are predicted. Discussions on nucleon–nucleon pairing energy and nucleon–nucleon short-range correlations are made. The found nuclear dependence of nucleon–nucleon short-range correlations may shed some lights on the short-range structure of nucleus.
International Nuclear Information System (INIS)
Ziegler, J.F.
1985-01-01
High energy ion implantation offers the oppertunity for unique structures in semiconductor processing. The unusual physical properties of such implantations are discussed as well as the special problems in masking and damage annealing. A review is made of proposed circuit structures which involve deep implantation. Examples are: deep buried bipolar collectors fabricated without epitaxy, barrier layers to reduce FET memory sensitivity to soft-fails, CMOS isolation well structures, MeV implantation for customization and correction of completed circuits, and graded reach-throughs to deep active device components. (orig.)
International Nuclear Information System (INIS)
Fortney, L.R.; Goshaw, A.T.; Walker, W.D.
1991-01-01
This progress report presents a review of research done over the past five years by the Duke High Energy Physics Group. This research has been centered at Fermilab where we have had a continuing involvement with both the Tevatron collider and fixed-target programs. In 1988 we began extensive detector R ampersand D for the SSC through its Major Subsystem Program. Duke has been an active member of the Solenoidal Detector Collaboration (SDC) since its formation. These last five years has also been used to finish the analysis of data from a series of hybrid bubble chamber experiments which formed the core of Duke's research program in the early 1980's
Stanev, Todor
2010-01-01
Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models
High energy particle transport code NMTC/JAM
International Nuclear Information System (INIS)
Niita, K.; Takada, H.; Meigo, S.; Ikeda, Y.
2001-01-01
We have developed a high energy particle transport code NMTC/JAM, which is an upgrade version of NMTC/JAERI97. The available energy range of NMTC/JAM is, in principle, extended to 200 GeV for nucleons and mesons including the high energy nuclear reaction code JAM for the intra-nuclear cascade part. We compare the calculations by NMTC/JAM code with the experimental data of thin and thick targets for proton induced reactions up to several 10 GeV. The results of NMTC/JAM code show excellent agreement with the experimental data. From these code validation, it is concluded that NMTC/JAM is reliable in neutronics optimization study of the high intense spallation neutron utilization facility. (author)
Exploring the nucleon helicity structure with pp collisions
International Nuclear Information System (INIS)
Deshpande, Abhay
2007-01-01
After a brief history of nucleon spin crisis I will motivate the need for a high energy polarized proton collider. I will then describe the distinct advantages of this new facility to study the spin structure of the proton. I will highlight the recent achievements of the RHIC Spin program from the experimental side, and review the achievements in terms of physics impact now and in near future
International Nuclear Information System (INIS)
Quigg, C.
1988-11-01
I discuss some possibilities for neutrino experiments in the fixed-target environment of the SPS, Tevatron, and UNK, with their primary proton beams of 0.4, 0.9, and 3.0 TeV. The emphasis is on unfinished business: issues that have been recognized for some time, but not yet resolved. Then I turn to prospects for proton-proton colliders to explore the 1-TeV scale. I review the motivation for new physics in the neighborhood of 1 TeV and mention some discovery possibilities for high-energy, high-luminosity hadron colliders and the implications they would have for neutrino physics. I raise the possibility of the direct study of neutrino interactions in hadron colliders. I close with a report on the status of the SSC project. 38 refs., 17 figs
International Nuclear Information System (INIS)
Signell, P.
1981-01-01
This project has involved five inter-related subprojects: (1) derivation of the intermediate range nucleon-nucleon interaction using a new method that utilizes much shorter and simpler analytic continuation through the unphysical region that lies between the πN and ππ physical regions of the N anti N → ππ amplitude (with signifantly improved accuracy for the nucleon-nucleon interaction); (2) construction of a short range phenomenological potential that, with the theoretical part mentioned above, gives a precise fit to the nucleon-nucleon data and is parameterized for easy use in nucleon calculations; (3) phase shift analyses of the world data below 400 MeV, especially the large amount of very precise data below 20 meV and the new data near 55 MeV that have never been analyzed properly; (4) the introduction of a K-matrix formulation of the Optimal Polynomial Expansion in order to accelerate convergence of the partial wave series at LAMPF energies; and (5) setting up of a cooperatively evaluated permanent nucleon-nucleon data bank in the 1-1200 MeV range that can be used by all nucleon-nucleon researchers
Nucleon structure from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Dinter, Simon
2012-11-13
In this thesis we compute within lattice QCD observables related to the structure of the nucleon. One part of this thesis is concerned with moments of parton distribution functions (PDFs). Those moments are essential elements for the understanding of nucleon structure and can be extracted from a global analysis of deep inelastic scattering experiments. On the theoretical side they can be computed non-perturbatively by means of lattice QCD. However, since the time lattice calculations of moments of PDFs are available, there is a tension between these lattice calculations and the results from a global analysis of experimental data. We examine whether systematic effects are responsible for this tension, and study particularly intensively the effects of excited states by a dedicated high precision computation. Moreover, we carry out a first computation with four dynamical flavors. Another aspect of this thesis is a feasibility study of a lattice QCD computation of the scalar quark content of the nucleon, which is an important element in the cross-section of a heavy particle with the nucleon mediated by a scalar particle (e.g. Higgs particle) and can therefore have an impact on Dark Matter searches. Existing lattice QCD calculations of this quantity usually have a large error and thus a low significance for phenomenological applications. We use a variance-reduction technique for quark-disconnected diagrams to obtain a precise result. Furthermore, we introduce a new stochastic method for the calculation of connected 3-point correlation functions, which are needed to compute nucleon structure observables, as an alternative to the usual sequential propagator method. In an explorative study we check whether this new method is competitive to the standard one. We use Wilson twisted mass fermions at maximal twist in all our calculations, such that all observables considered here have only O(a{sup 2}) discretization effects.
Nucleon structure from lattice QCD
International Nuclear Information System (INIS)
Dinter, Simon
2012-01-01
In this thesis we compute within lattice QCD observables related to the structure of the nucleon. One part of this thesis is concerned with moments of parton distribution functions (PDFs). Those moments are essential elements for the understanding of nucleon structure and can be extracted from a global analysis of deep inelastic scattering experiments. On the theoretical side they can be computed non-perturbatively by means of lattice QCD. However, since the time lattice calculations of moments of PDFs are available, there is a tension between these lattice calculations and the results from a global analysis of experimental data. We examine whether systematic effects are responsible for this tension, and study particularly intensively the effects of excited states by a dedicated high precision computation. Moreover, we carry out a first computation with four dynamical flavors. Another aspect of this thesis is a feasibility study of a lattice QCD computation of the scalar quark content of the nucleon, which is an important element in the cross-section of a heavy particle with the nucleon mediated by a scalar particle (e.g. Higgs particle) and can therefore have an impact on Dark Matter searches. Existing lattice QCD calculations of this quantity usually have a large error and thus a low significance for phenomenological applications. We use a variance-reduction technique for quark-disconnected diagrams to obtain a precise result. Furthermore, we introduce a new stochastic method for the calculation of connected 3-point correlation functions, which are needed to compute nucleon structure observables, as an alternative to the usual sequential propagator method. In an explorative study we check whether this new method is competitive to the standard one. We use Wilson twisted mass fermions at maximal twist in all our calculations, such that all observables considered here have only O(a 2 ) discretization effects.
Fifth high-energy heavy-ion study
International Nuclear Information System (INIS)
1981-10-01
This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest available in the cosmic radiation. The lower range, particularly below 100 MeV/nucleon, will be under intense study in the near future with machines such as the upgraded Bevalac, Michigan State University Superconducting Cyclotron, GANIL in France, and the SC at CERN. Recently, the high energy collision regime has been expanded by the successful operation of the CERN ISR with alpha particles. Second, in addition to an extensive program of invited talks, we decided for the first time to actively solicit contributions. Forty-seven individual items from the conference were prepared separately for the data base
Fifth high-energy heavy-ion study
Energy Technology Data Exchange (ETDEWEB)
1981-10-01
This was the fifth of a continuing series of summer studies held at LBL to discuss high energy heavy ion collisions. Recently, a similar meeting has been held on alternate years at GSI (Darmstadt); and, in 1979, we held a meeting at LBL exclusively devoted to ultra-relativistic nuclear collisions. Two new features distinguish this study from earlier meetings in the series. First, the energy range for discussion was broadened by including collisions from about 20 MeV/nucleon to the highest available in the cosmic radiation. The lower range, particularly below 100 MeV/nucleon, will be under intense study in the near future with machines such as the upgraded Bevalac, Michigan State University Superconducting Cyclotron, GANIL in France, and the SC at CERN. Recently, the high energy collision regime has been expanded by the successful operation of the CERN ISR with alpha particles. Second, in addition to an extensive program of invited talks, we decided for the first time to actively solicit contributions. Forty-seven individual items from the conference were prepared separately for the data base. (GHT)
Radical conservatism and nucleon decay
International Nuclear Information System (INIS)
Wilczek, Frank
2000-01-01
Unification of couplings, observation of neutrino masses in the expected range, and several other considerations confirm central implications of straightforward gauge unification based on SO(10) or a close relative and incorporating low-energy supersymmetry. The remaining outstanding consequence of this circle of ideas, yet to be observed, is nucleon instability. Clearly, we should aspire to be as specific as possible regarding the rate and form of such instability. I argue that not only esthetics, but also the observed precision of unification of couplings, favors an economical symmetry-breaking (Higgs) structure. Assuming this, one can exploit its constraints to build reasonably economical, overconstrained yet phenomenologically viable models of quark and lepton masses. Putting it all together, one arrives at reasonably concrete, hopeful expectations regarding nucleon decay. These expectations are neither ruled out by existing experiments, nor hopelessly inaccessible. Furthermore, the branching fractions can discriminate among different possibilities for physics at the unification scale
Energy Technology Data Exchange (ETDEWEB)
Chand, Ramesh
1963-10-15
Total scattering and absorption cross sections for anti K-nucleon collisions in I = 1, p_{3/2} - channel are given as functions of the two sets of energy dependent anti KN scattering parameters solutions, called solution A' and solution B'. These scattering parameters are obtained by linear interpolations between Watson's amplitudes around 400 MeV/c and the amplitude at the position of the pole in the anti KN scattering amplitude corresponding to the p_{3/2}-wave 1385 MeV Y_{1}-resonance with 50 MeV width. The zero-range expansion for p-wave anti K-nucleon phase shift and the scattering parameters of Watson's solution B are found to be in violation of the requirements of causality and of positive definiteness of transition probabilities. (auth)
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
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
Rapidity and multiplicity correlations in high energy hadronic collisions
International Nuclear Information System (INIS)
Heiselberg, H.
1993-01-01
Rapidity and multiplicity correlations of particle production in high energy hadronic collisions are studied. A simple model including short range correlations in rapidity due to clustering and long range correlations due to energy conservation is able to describe the two-body correlation functions well hadron-nucleon collisions around lab energies of 250 GeV. In this model fractional moments are calculated and compared to data. The strong rise of the factorial moments in rapidity intervals by size δy∝1 can be explained by long and short range correlation alone whereas the factorial moments approach a constant value at very small δy due to lack of correlations also in agreement with experiment. There is therefore no need for introducing intermittency in the particle production in hadronic collisions at these energies. (orig.)
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
International Nuclear Information System (INIS)
Eletsky, V.L.
1991-01-01
The problem of temperature dependence of nucleon mass is addressed by considering a retarded correlator of two currents with quantum numbers of a nucleon at finite temperature T π in the chiral limit. It is shown that at Euclidean momenta the leading one-loop corrections arise from direct interaction of thermal pions with the currents. A dispersive representation for the correlator shows that this interaction smears the nucleon pole over frequency interval with width ∼ T. This interaction does not change the exponential fall-off of the correlator in Euclidean space but gives an O(T 2 /F π 2 ) contribution to the pre-exponential factor. 11 refs. (author)
International Nuclear Information System (INIS)
Kernan, A.; Shen, B.C.; Ma, E.
1997-01-01
This proposal is for the continuation of the High Energy Physics program at the University of California at Riverside. In hadron collider physics the authors will complete their transition from experiment UA1 at CERN to the DZERO experiment at Fermilab. On experiment UA1 their effort will concentrate on data analysis at Riverside. At Fermilab they will coordinate the high voltage system for all detector elements. They will also carry out hardware/software development for the D0 muon detector. The TPC/Two-Gamma experiment has completed its present phase of data-taking after accumulating 160 pb - 1 of luminosity. The UC Riverside group will continue data and physics analysis and make minor hardware improvement for the high luminosity run. The UC Riverside group is participating in design and implementation of the data acquisition system for the OPAL experiment at LEP. Mechanical and electronics construction of the OPAL hadron calorimeter strip readout system is proceeding on schedule. Data analysis and Monte Carlo detector simulation efforts are proceeding in preparation for the first physics run when IEP operation comenses in fall 1989
Department of High Energy Physics: Overview
International Nuclear Information System (INIS)
Nassalski, J.
2000-01-01
Full text: The activities of the Department of High Energy Physics are centered around experiments performed at accelerators in the following laboratories: 1. At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - DELPHI at LEP e + e - storage ring is concerned mainly with the tests of the Standard Model, b-quark physics, gamma-gamma interactions and search for Higgs boson and supersymmetric particles; - NA48 - studies of the CP-violation in rare K 0 decays; - SMC - Spin Muon Collaboration is investigating the spin dependent nucleon structure functions and the gluon role in the nucleon spin; - NA49 and WA98 deal with heavy ion physics looking for possible effects of the phase transition to the quark-gluon plasma state. 2. At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - the production of light mesons near threshold and their rare decays. 3. At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering of electrons and protons, proton structure functions, diffractive photon-proton interactions. The groups of our Department participated in the construction phase of the experiments, both in hardware and in development of the software used in data analysis. Presently they take part in the data acquisition, detector performance supervision and data analysis. The Department is also actively involved in the preparation of new experiments: - CMS (Compact Muon Solenoid) and LHCb (b-quark production and CP-violation) at the LHC (Large Hadron Collider) at CERN, - ALICE - experiment to study the heavy ion interactions at the LHC, - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) at the SPS at CERN, - WASA-Promice - a new version of the WASA detector at CELSIUS in Uppsala, - relativistic hyperfragment production experiment in Dubna, Russia. A small mechanical workshop is attached to our Department. It is involved in the preparation of the COMPASS experiment and participated in the construction of the WASA - Promice
Department of High Energy Physics: Overview
International Nuclear Information System (INIS)
Bialkowska, H.
2001-01-01
Full text:The activities of the Department of High Energy Physics are centered around experiments performed at accelerators in the following laboratories: At CERN, the European Laboratory for Particle Physics in Geneva, Switzerland: - DELPHI at LEP e + e - storage ring is concerned mainly with the tests of the Standard Model, b-quark physics, gamma-gamma interactions and search for Higgs boson and supersymmetric particles; - NA48 - studies of the CP-violation and rare K 0 decays; - SMC - Spin Muon Collaboration is investigating the spin dependent nucleon structure functions and the gluon role in the nucleon spin; - NA49 and WA98 deal with heavy ion physics looking for possible effects of the phase transition in the quark-gluon plasma state. At CELSIUS Storage Ring in Uppsala, Sweden: - WASA - a precise study of near threshold production of light mesons, and their decays. At DESY in Hamburg, Germany: - ZEUS - deep inelastic scattering of electrons and protons, proton structure functions, diffractive photon-proton interactions. The groups of our Department participated in the construction phase of the experiments, both in hardware and in development of the software used in data analysis. Presently they take part in the data collection, detector performance supervision and data analysis. The Department is also actively involved in the preparation of new experiments: - CMS (Compact Muon Solenoid) and LHCb (b-quark production and CP-violation) at the LHC (Large Hadron Collider) at CERN; - ALICE - experiment to study the heavy ion interactions at the LHC; - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) at the SPS at CERN; - WASA- 4π - commissioning of a new version of the WASA detector at CELSIUS in Uppsala; - study of charge exchange processes in d-p collisions at Nuclotron in Dubna. A small mechanical workshop is attached to our Department. It is involved in the preparation of the COMPASS experiment and participated in the construction of
High energy astrophysical techniques
Poggiani, Rosa
2017-01-01
This textbook presents ultraviolet and X-ray astronomy, gamma-ray astronomy, cosmic ray astronomy, neutrino astronomy, and gravitational wave astronomy as distinct research areas, focusing on the astrophysics targets and the requirements with respect to instrumentation and observation methods. The purpose of the book is to bridge the gap between the reference books and the specialized literature. For each type of astronomy, the discussion proceeds from the orders of magnitude for observable quantities. The physical principles of photon and particle detectors are then addressed, and the specific telescopes and combinations of detectors, presented. Finally the instruments and their limits are discussed with a view to assisting readers in the planning and execution of observations. Astronomical observations with high-energy photons and particles represent the newest additions to multimessenger astronomy and this book will be of value to all with an interest in the field.
Induced hyperon-nucleon-nucleon interactions and the hyperon puzzle
Energy Technology Data Exchange (ETDEWEB)
Wirth, Roland; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)
2016-07-01
There is a strong experimental and theoretical interest in determining the structure of hypernuclei and the effect of strangeness in strongly interacting many-body systems. Recently, we presented the first calculations of hypernuclei in the p shell from first principles. However, these calculations showed either slow convergence with respect to model-space size or, when the hyperon-nucleon potential is transformed via the Similarity Renormalization Group, strong induced three-body terms. By including these induced hyperon-nucleon-nucleon (YNN) terms explicitly, we get precise binding and excitation energies. We present first results for p-shell hypernuclei and discuss the origin of the YNN terms, which are mainly driven by the evolution of the Λ-Σ conversion terms. We find that they are tightly connected to the hyperon puzzle, a long-standing issue where the appearance of hyperons in models of neutron star matter lowers the predicted maximum neutron star mass below the bound set by the heaviest observed objects.
Internal Spin Structure of the Nucleon in Polarized Deep Inelastic Muon-Nucleon Scattering
International Nuclear Information System (INIS)
Wislicki, W.
1998-01-01
We present the study of the internal spin structure of the nucleon in spin-dependent deep inelastic scattering of muons on nucleons. The data were taken by the NA47 experiment of the Spin Muon Collaboration (SMC) on the high energy muon beam at CERN. The experiment used the polarized proton and deuteron targets. The structure function g 1 p (x) and g 1 d (x) were determined from the asymmetries of the spin-dependent event rates in the range of 0.003 2 >=10 GeV 2 . Using the first moments of these structure functions an agreement with the Bjorken sum rule prediction was found within one standard deviation. The first moments of g 1 (x), for both proton and deuteron, are smaller than the Ellis-Jaffe sum rule prediction. This disagreement can be interpreted in terms of negative polarization of the strange sea in the nucleon. The singlet part of the axial current matrix element can be interpreted as an overall spin carried by quarks in the nucleon. Its value is significantly smaller than nucleon spin. Semi-inclusive asymmetries of yields of positive and negative hadrons produced on both targets were also measured and analysed in term of quark-parton model, together with inclusive asymmetries. From this analysis the quark spin distributions were determined, separately for valence u and d quarks and for non-strange sea quarks. Valence u quarks are positively polarized and their polarization increases with x. Valence d quarks are negatively polarized and their polarization does not exhibit any x-dependence. The non-strange sea is unpolarized in the whole measured range of x. The first moments of the valance quark spin distributions were found consistent with the values obtained from weak decay constants F and D and their second moments are consistent with lattice QCD calculations. In the QCD analysis of the world data the first moment of the gluon spin distribution was found with a large error. Also, a search for a non-perturbative anomaly at high x was done on the world
QCD sum rule for nucleon in nuclear matter
International Nuclear Information System (INIS)
Mallik, S.; Sarkar, Sourav
2010-01-01
We consider the two-point function of nucleon current in nuclear matter and write a QCD sum rule to analyse the residue of the nucleon pole as a function of nuclear density. The nucleon self-energy needed for the sum rule is taken as input from calculations using phenomenological N N potential. Our result shows a decrease in the residue with increasing nuclear density, as is known to be the case with similar quantities. (orig.)
Cosmic rays at ultra high energies (Neutrinos.)
International Nuclear Information System (INIS)
Ahlers, M.; Ringwald, A.; Tu, H.
2005-06-01
Resonant photopion production with the cosmic microwave background predicts a suppression of extragalactic protons above the famous Greisen-Zatsepin-Kuzmin cutoff at about E GZK ∼ 5 x 10 10 GeV. Current cosmic ray data measured by the AGASA and HiRes Collaborations do not unambiguously confirm the GZK cutoff and leave a window for speculations about the origin and chemical composition of the highest energy cosmic rays. In this work we analyze the possibility of strongly interacting neutrino primaries and derive model-independent quantitative requirements on the neutrino-nucleon inelastic cross section for a viable explanation of the cosmic ray data. Search results on weakly interacting cosmic particles from the AGASA and RICE experiments are taken into account simultaneously. Using a flexible parameterization of the inelastic neutrino-nucleon cross section we find that a combined fit of the data does not favor the Standard Model neutrino-nucleon inelastic cross section, but requires, at 90% confidence level, a steep increase within one energy decade around E GZK by four orders of magnitude. We illustrate such an enhancement within some extensions of the Standard Model. The impact of new cosmic ray data or cosmic neutrino search results on this scenario, notably from the Pierre Auger Observatory soon, can be immediately evaluated within our approach. (orig.)
International Nuclear Information System (INIS)
Saleh, Z.A.; Abdel-Hafez, A.
2002-01-01
Results from EMU-01/12 collaboration for the experimental data on multifragmentation of gold residual nuclei created in the interactions with photoemulsion nuclei at the energy of 10.7 GeV/nucleon are presented together with the experimental data on multifragmentation of krypton created on the interactions with photoemulsion nuclei at energy of 0.9 GeV/nucleon. The data are analyzed in the frame of the statistical model of multifragmentation. It is obvious that there are two regimes for nuclear multifragmentation: the former is when less than one-half of nucleons of projectile nucleus are knocked out, the later is when more than one-half of nucleons are knocked out. Residual nuclei with masses close to each other created at different reactions are fragmented practically simultaneously when more than one-half of nucleons of original nuclei are knocked out. These results give an indication that projectiles other than Gold and Krypton may give the same characterization on interaction with emulsion nuclei at high energies
High energy magnetic excitations
International Nuclear Information System (INIS)
Endoh, Yasuo
1988-01-01
The report emphasizes that the current development in condensed matter physics opens a research field fit to inelastic neutron scattering experiments in the eV range which is easilly accessed by spallation neutron sources. Several important subjects adopted at thermal reactors are shown. It is desired to extend the implementation of the spectroscopic experiments for investigation of higher energy magnetic excitations. For La 2 CuO 4 , which is the mother crystal of the first high Tc materials found by Bednortz and Muller, it seems to be believed that the magnetism is well characterized by the two-dimensional Heisenberg antiferromagnetic Hamiltonian, and it is widely accepted that the magnetism is a most probable progenitor of high Tc superconductors. The unusual properties of spin correlations in this crystal have been studied extensively by standard neutron scattering techniques with steady neutrons at BNL. FeSi is not ordered magnetically but shows a very unique feature of temperature induced magnetism, which also has been studied extensively by using the thermal neutron scattering technique at BNL. In these experiments, polarized neutrons are indispensable to extract the clean magnetic components out of other components of non-magnetic scattering. (N.K.)
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
Computing in high energy physics
Energy Technology Data Exchange (ETDEWEB)
Watase, Yoshiyuki
1991-09-15
The increasingly important role played by computing and computers in high energy physics is displayed in the 'Computing in High Energy Physics' series of conferences, bringing together experts in different aspects of computing - physicists, computer scientists, and vendors.
Three nucleon interaction and nuclear composition
International Nuclear Information System (INIS)
Pandharipande, V.R.
1983-01-01
The author discusses results of some of the calculations carried out by J. Carlson, I. Lagaris, J. Lomnitz-Adler, R.A. Smith, R.B. Wiringa and himself to study the three nucleon interaction. The group has attempted to calculate the wavefunctions and binding energies of 3 H, 3 He, 4 He and nuclear matter, with the variational method, from a nonrelativistic Hamiltonian. Only nucleon degrees of freedom are retained in this Hamiltonian; the effects of other degrees of freedom are implicit in the two and three nucleon potentials. The author discusses further the calculations carried out, in collaboration with B. Friman, and R.B. Wiringa, to study the composition of nuclei. Nucleons interact by many processes including exchange of pions with or without excitation to isobar (Δ) states. Thus the nucleus contains pions being exchanged, and some nucleons in the Δ state. The group attempts to calculate the number and momentum distribution of these exchanged pions, and the fraction of time a nucleon in the nucleus is in the Δ state. 21 references, 4 figures
Energy spectrum of tau leptons induced by the high energy Earth-skimming neutrinos
International Nuclear Information System (INIS)
Tseng, J.-J.; Yeh, T.-W.; Lee, F.-F.; Lin, G.-L.; Athar, H.; Huang, M.A.
2003-01-01
We present a semianalytic calculation of the tau-lepton flux emerging from the Earth induced by incident high energy neutrinos interacting inside the Earth for 10 5 ≤E ν /GeV≤10 10 . We obtain results for the energy dependence of the tau-lepton flux coming from the Earth-skimming neutrinos, because of the neutrino-nucleon charged-current scattering as well as the resonant ν(bar sign) e e - scattering. We illustrate our results for several anticipated high energy astrophysical neutrino sources such as the active galactic nuclei, the gamma-ray bursts, and the Greisen-Zatsepin-Kuzmin neutrino fluxes. The tau-lepton fluxes resulting from rock-skimming and ocean-skimming neutrinos are compared. Such comparisons can render useful information about the spectral indices of incident neutrino fluxes
Energy Technology Data Exchange (ETDEWEB)
Prosper, Harrison B. [Florida State Univ., Tallahassee, FL (United States); Adams, Todd [Florida State Univ., Tallahassee, FL (United States); Askew, Andrew [Florida State Univ., Tallahassee, FL (United States); Berg, Bernd [Florida State Univ., Tallahassee, FL (United States); Blessing, Susan K. [Florida State Univ., Tallahassee, FL (United States); Okui, Takemichi [Florida State Univ., Tallahassee, FL (United States); Owens, Joseph F. [Florida State Univ., Tallahassee, FL (United States); Reina, Laura [Florida State Univ., Tallahassee, FL (United States); Wahl, Horst D. [Florida State Univ., Tallahassee, FL (United States)
2014-12-01
The High Energy Physics group at Florida State University (FSU), which was established in 1958, is engaged in the study of the fundamental constituents of matter and the laws by which they interact. The group comprises theoretical and experimental physicists, who sometimes collaborate on projects of mutual interest. The report highlights the main recent achievements of the group. Significant, recent, achievements of the group’s theoretical physicists include progress in making precise predictions in the theory of the Higgs boson and its associated processes, and in the theoretical understanding of mathematical quantities called parton distribution functions that are related to the structure of composite particles such as the proton. These functions are needed to compare data from particle collisions, such as the proton-proton collisions at the CERN Large Hadron Collider (LHC), with theoretical predictions. The report also describes the progress in providing analogous functions for heavy nuclei, which find application in neutrino physics. The report highlights progress in understanding quantum field theory on a lattice of points in space and time (an area of study called lattice field theory), the progress in constructing several theories of potential new physics that can be tested at the LHC, and interesting new ideas in the theory of the inflationary expansion of the very early universe. The focus of the experimental physicists is the Compact Muon Solenoid (CMS) experiment at CERN. The report, however, also includes results from the D0 experiment at Fermilab to which the group made numerous contributions over a period of many years. The experimental group is particularly interested in looking for new physics at the LHC that may provide the necessary insight to extend the standard model (SM) of particle physics. Indeed, the search for new physics is the primary task of contemporary particle physics, one motivated by the need to explain certain facts, such as the
Spin structure in high energy processes: Proceedings
Energy Technology Data Exchange (ETDEWEB)
DePorcel, L.; Dunwoodie, C. [eds.
1994-12-01
This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.
Spin structure in high energy processes: Proceedings
International Nuclear Information System (INIS)
DePorcel, L.; Dunwoodie, C.
1994-12-01
This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z 0 s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ( 3 HE) and the Bjoerken sum rule; a consumer's guide to lattice QCD results; top ten models constrained by b → sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere
International Nuclear Information System (INIS)
Abbas, Afsar
1992-01-01
The surprising answer to this question Is nucleon deformed? is : Yes. The evidence comes from a study of the quark model of the single nucleon and when it is found in a nucleus. It turns out that many of the long standing problems of the Naive Quark Model are taken care of if the nucleon is assumed to be deformed. Only one value of the parameter P D ∼1/4 (which specifies deformation) fits g A (the axial vector coupling constant) for all the semileptonic decay of baryons, the F/D ratio, the pion-nucleon-delta coupling constant fsub(πNΔ), the double delta coupling constant 1 fsub(πΔΔ), the Ml transition moment μΔN and g 1 p the spin structure function of proton 2 . All this gives strong hint that both neutron and proton are deformed. It is important to look for further signatures of this deformation. When this deformed nucleon finds itself in a nuclear medium its deformation decreases. So much that in a heavy nucleus the nucleons are actually spherical. We look into the Gamow-Teller strengths, magnetic moments and magnetic transition strengths in nuclei to study this property. (author). 15 refs
Hadron-nucleus interactions in the nucleon resonance region
Energy Technology Data Exchange (ETDEWEB)
Gessler, Stefanie
2017-06-15
Experiments with high-energy hadron beams have found renewed attention. In the near future nuclear studies with hadron beams are planned at least at two facilities, namely J-PARC in Japan and GSI/FAIR. The aim of this work is an exploratory investigation of interactions of mesons and baryons with nuclei at energies of interest for future research with antiprotons at FAIR. The theoretical discussion is started with an introductory presentation of the optical model and Eikonal theory as appropriate tools for the description of scattering processes at high energies. In antiproton interactions with nucleons and nuclei, annihilation processes into pions are playing the major role for the reaction dynamics. Therefore, we consider first the interactions of pions with nuclei by deriving an extended selfenergy scheme for a large range of incident pion energies. In order to have a uniform description over a broad energy interval, the existing approaches had to be reconsidered and in essential parts reformulated and extended. A central result is the treatment of pion-nucleus self-energies from high lying N{sup *} resonances. Only by including those channels in a proper manner into the extended pion optical potential, pion-nucleus scattering could be described over the required large energy range. At low energies the well known Kisslinger potential is recapped. Next, the same type of reaction theory is used to analyze antiproton-nucleon and nucleus scattering from low to highly relativistic energies. The reaction dynamics of antiproton interactions with nuclear targets is discussed. We start with a new approach to antiproton-nucleon scattering. A free-space antiproton-nucleon T-matrix is derived, covering an energy range as wide as from 100 MeV up to 15 GeV. Eikonal theory is used to describe the antiproton scattering amplitudes in momentum and in coordinate space. We consider, in particular, interactions with nuclei at energies around and well above 1 GeV. The antiproton
Hadron-nucleus interactions in the nucleon resonance region
International Nuclear Information System (INIS)
Gessler, Stefanie
2017-06-01
Experiments with high-energy hadron beams have found renewed attention. In the near future nuclear studies with hadron beams are planned at least at two facilities, namely J-PARC in Japan and GSI/FAIR. The aim of this work is an exploratory investigation of interactions of mesons and baryons with nuclei at energies of interest for future research with antiprotons at FAIR. The theoretical discussion is started with an introductory presentation of the optical model and Eikonal theory as appropriate tools for the description of scattering processes at high energies. In antiproton interactions with nucleons and nuclei, annihilation processes into pions are playing the major role for the reaction dynamics. Therefore, we consider first the interactions of pions with nuclei by deriving an extended selfenergy scheme for a large range of incident pion energies. In order to have a uniform description over a broad energy interval, the existing approaches had to be reconsidered and in essential parts reformulated and extended. A central result is the treatment of pion-nucleus self-energies from high lying N * resonances. Only by including those channels in a proper manner into the extended pion optical potential, pion-nucleus scattering could be described over the required large energy range. At low energies the well known Kisslinger potential is recapped. Next, the same type of reaction theory is used to analyze antiproton-nucleon and nucleus scattering from low to highly relativistic energies. The reaction dynamics of antiproton interactions with nuclear targets is discussed. We start with a new approach to antiproton-nucleon scattering. A free-space antiproton-nucleon T-matrix is derived, covering an energy range as wide as from 100 MeV up to 15 GeV. Eikonal theory is used to describe the antiproton scattering amplitudes in momentum and in coordinate space. We consider, in particular, interactions with nuclei at energies around and well above 1 GeV. The antiproton
Potentials of the inverse scattering problem in the three-nucleon problem
International Nuclear Information System (INIS)
Pushkash, A.M.; Simenog, I.V.; Shapoval, D.V.
1993-01-01
Possibilities of using the method of the inverse scattering problem for describing simultaneously the two-nucleon and the low-energy three-nucleon data in the S-interaction approximation are examined. 20 refs., 3 figs., 1 tab
Insights into nucleon structure from parton distributions
Energy Technology Data Exchange (ETDEWEB)
Melnitchouk, Wally [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2017-05-01
We review recent progress in understanding the substructure of the nucleon from global QCD analysis of parton distribution functions (PDFs). New high-precision data onW-boson production in p ¯ p collisions have significantly reduced the uncertainty on the d=u PDF ratio at large values of x, indirectly constraining models of the medium modification of bound nucleons. Drell-Yan data from pp and pd scattering reveal new information on the d¯-u¯ asymmetry, clarifying the role of chiral symmetry breaking in the nucleon. In the strange sector, a new chiral SU(3) analysis finds a valence-like component of the strange-quark PDF, giving rise to a nontrivial s- ¯ s asymmetry at moderate x values. We also review recent analyses of charm in the nucleon, which have found conflicting indications of the size of the nonperturbative charm component.
Nucleon-nucleon scattering and different meson exchanges
International Nuclear Information System (INIS)
Osman, A.
1985-10-01
The iterative and noniterative diagrams with different meson exchange are investigated. The α, πβ and πγ meson exchange, (where α=π, rho, σ, ω, eta and delta; β=π, rho, σ and ω; γ=π and rho), are considered. These diagrams are taken to involve the nucleon-nucleon, the nucleon-isobar and the isobar-isobar intermediate states. The diagrams are calculated in momentum space following the noncovariant perturbation theory. The role of each of these diagrams is examined by calculating its contribution to the nucleon-nucleon interaction. The potential model is taken to include one-boson-exchange terms in addition to these diagrams. The nucleon-nucleon scattering phase shifts are described successfully showing the importance of tensor force. The contributions of the different parts are studied in the nucleon-nucleon scattering. (author)
International Nuclear Information System (INIS)
Kernan, A.; Shen, B.C.; Ma, E.
1997-01-01
This proposal is for the continuation of the High Energy Physics Program at the University of California, Riverside. In 1990, we will concentrate on analysis of LEP data from the OPAL detector. We expect to record 10 5 Z's by the end of 1989 and 10 6 in 1990. This data will be used to measure the number of quark-lepton families in the universe. In the second half of 1990 we will also be occupied with the installation of the D-Zero detector in the Tevatron Collider and the preparation of software for the 1991 run. A new initiative made possible by generous university support is a laboratory for detector development at UCR. The focus will be on silicon strip tracking detectors both for the D-Zero upgrade and for SSC physics. The theory program will pursue further various mass-generating radiative mechanisms for understanding small quark and lepton masses as well as some novel phenomenological aspects of supersymmetry
High energy plasma accelerators
International Nuclear Information System (INIS)
Tajima, T.
1985-05-01
Colinear intense laser beams ω 0 , kappa 0 and ω 1 , kappa 1 shone on a plasma with frequency separation equal to the electron plasma frequency ω/sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ω/sub pe//e of the order of 1GeV/cm for a plasma density of 10 18 cm -3 through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed
K-nucleon scattering and the cloudy bag model
International Nuclear Information System (INIS)
Jennings, B.K.
1986-01-01
The cloudy bag model (CBM) has been applied with considerable success to low energy meson-nucleon scattering. In this talk I will describe in particular calculations for kaon-nucleon and antikaon-nucleon scattering. The main emphasis will be on s-waves with special attention paid to the antikaon-nucleon system in the isospin zero channel where the Λ(1405) is important. In the CBM the Λ(1405) is an antikaon-nucleon bound state and I show that this interpretation is consistent with the antikaon-nucleon scattering in the region of the Λ(1670) and Λ(1800) although ambiguities in the phase shift analysis prevent a definite conclusion
K-nucleon scattering and the cloudy bag model
Jennings, B. K.
1986-10-01
The cloudy bag model (CBM) has been applied with considerable success to low energy meson-nucleon scattering. In this talk I will describe in particular calculations for kaon-nucleon and antikaon-nucleon scattering. The main emphasis will be on s-waves with special attention paid to the antikaon-nucleon system in the isospin zero channel where the Λ(1405) is important. In the CBM the Λ(1405) is an antikaon-nucleon bound state and I show that this interpretation is consistent with the antikaon-nucleon scattering in the region of the Λ(1670) and Λ(1800) although ambiguities in the phase shift analysis prevent a definite conclusion.
Raymond, Arnold
2000-04-01
The talk will present the story of a series of experiments, beginning in 1973 and continuing today, that have measured the internal structure of nuclei and the nucleons using high energy beams of electrons and photons at the Stanford Linear Accelerator Center. These experiments have probed nuclear and nucleon structure in the energy and momentum transfer region where the meson-nucleon description merges with the quark-gluon picture. The experiments have worked at the border between nuclear and particle physics, and were conducted by large collaborative teams. Some were carried out in the context of a special program, called NPAS (Nuclear Physics at SLAC). The early results from these measurements helped stimulate the ideas and helped train and motivate the physicists who went on to build the Jefferson Laboratory. A brief summary of some highlights from the early measurements and updates on recent results will be given.
A semiclassical distorted wave theory of inclusive nucleon inelastic scattering to continuum
International Nuclear Information System (INIS)
Kawai, M.; Luo, Y.L.
1989-01-01
A semiclassical model is presented for the one step process of the inclusive nucleon inelastic scattering to the continuum. In the model, we use distorted waves for describing the motion of the incident and the exit nucleon, and the Thomas-Fermi model for the initial and the final states of the target nucleus. The averaged two-body cross section inside the nucleus is given by Kikuchi-Kawai expression. The model gives a closed form formula for the double differential cross section. No free parameter is included. We apply the model to the inclusive nucleon inelastic scattering from Al, Sn and Bi at 62 MeV, and Ni at 164 MeV. The angular distribution experimental data are reproduced very well except for small and large angle regions. The calculated energy spectra agree with the experimental data very well in the middle angle region and at high exit energies. (author)
Equidistant structure and effective nucleon mass in nuclear matter
International Nuclear Information System (INIS)
Tezuka, Hirokazu.
1981-11-01
The effective nucleon mass of the Equidistant Multi-Layer Structure (EMULS) is discussed self-consistently. In the density region where the Fermi gas state in nuclear matter is unstable against the density fluctuation, the EMULS gives lower binding energy. It is, however, shown that such a structure with an ordinary nucleon mass collapses due to too strong attraction. We point out that such a collapse can be avoided by taking account of an effective nucleon mass affected by the localization of nucleons. (author)
Single nucleon-nucleon collision model for subthreshold pion production in heavy ion collisions
International Nuclear Information System (INIS)
Bellini, V.; Di Toro, M.; Bonasera, A.
1985-01-01
We show that inclusive experimental data on subthreshold pion production in 12 C + 12 C and 16 O + 12 C collisions can be reproduced using a first chance Nucleon-Nucleon (NN) collision mechanism. Pauli blocking effects are extremely important while π-resorption can be safely neglected for these light systems. We apply our method at various beam energies. The possible importance of collective dynamical effects around the physical threshold is finally suggested
International Nuclear Information System (INIS)
Barjon, R.; Breynat, G.
1987-01-01
This patent describes a generator of fast neutrons only slightly contaminated by neutrons of energy less than 15 MeV, comprising a source of charged particles of energy equal to at least 15 MeV, a target made of lithium deuteride, and means for cooling the target. The target comprises at least two elements placed in series in the path of the charged particles and separated from each other, the thickness of each of the elements being selected as a function of the average energy of the charged particles emitted from the source and the energy of the fast neutrons to be generated such that neutrons of energy equal to at least 15 MeV are emitted in the forward direction in response to the bombardment of the target from behind by the charged particles. The target cooling means comprises means for circulating between and around the elements a gas which does not chemically react with lithium deuteride
Heavy quark production in semihard interactions of nucleons
International Nuclear Information System (INIS)
Levin, E.M.; Ryskin, M.G.; Shabel'skij, Yu.M.; Shuvaev, A.G.
1991-01-01
Cross section of semihard process (heavy quark production) in the interactions of high-energy nucleons is calculated. The normalization of gluon structure function at small x and the role of absorption corrections are discussed in detail. The virtuality of interacting gluons as well as their transverse motion and possible various polarizations are accounted for in calculations. Comparatively large cross section of the high-energy inclusive b-quark production (σ(b-barb) is predicted, in particular, σ(p-barp→b-barb)=150-300 μb at √s=1.8 TeV
The ultimate structure of matter: The high energy physics program from the 1950s through the 1980s
International Nuclear Information System (INIS)
1990-02-01
This discusses the following topics in High Energy Physics: The Particle Zoo; The Strong and the Weak; The Particle Explosion; Deep Inside the Nucleon; The Search for Unity; Physics in Collision; The Standard Model; Particles and the Cosmos; and Practical Benefits
The ultimate structure of matter: The high energy physics program from the 1950s through the 1980s
Energy Technology Data Exchange (ETDEWEB)
1990-02-01
This discusses the following topics in High Energy Physics: The Particle Zoo; The Strong and the Weak; The Particle Explosion; Deep Inside the Nucleon; The Search for Unity; Physics in Collision; The Standard Model; Particles and the Cosmos; and Practical Benefits.
Dosimetry of high energy radiation
Sahare, P D
2018-01-01
High energy radiation is hazardous to living beings and a threat to mankind. The correct estimation of the high energy radiation is a must and a single technique may not be very successful. The process of estimating the dose (the absorbed energy that could cause damages) is called dosimetry. This book covers the basic technical knowledge in the field of radiation dosimetry. It also makes readers aware of the dangers and hazards of high energy radiation.
16th Workshop on High Energy Spin Physics
2016-01-01
The Workshop will cover a wide range of spin phenomena at high and intermediate energies such as: recent experimental data on spin physics the nucleon spin structure and GPD's spin physics and QCD spin physics in the Standard Model and beyond T-odd spin effects polarization and heavy ion physics spin in gravity and astrophysics the future spin physics facilities spin physics at NICA polarimeters for high energy polarized beams acceleration and storage of polarized beams the new polarization technology related subjects The Workshop will be held in the Bogoliubov Laboratory of Theoretical Physics of the Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia. The program of the workshop will include plenary and parallel (if necessary) sessions. Plenary sessions will be held in the Conference Hall. Parallel sections will take place in the same building. There will be invited talks (up to 40 min) and original reports (20 min). The invited speakers will present new experimental and theoretical re...
Theoretical aspects of the nucleon-nucleon workshop
International Nuclear Information System (INIS)
Silbar, R.R.
1984-01-01
This report concentrates on the inelastic NN system from 300 to 1500 MeV. Topics covered include the visibility of quark signals, dibaryons, the model dependence of predicted NN inelasticities, and a review of how well present conventional models compare with a rapidly expanding database. The general conclusion is that there is so far no clear evidence in the NN system at intermediate energies for unconventional dibaryon resonances. Short remarks are also made concerning one theoretical contribution on elastic scattering and on new experimental results for deuteron photo-disintegration and pion-nucleon charge exchange. 11 references
Chiral nucleon-nucleon forces in nuclear structure calculations
Directory of Open Access Journals (Sweden)
Coraggio L.
2016-01-01
Full Text Available Realistic nuclear potentials, derived within chiral perturbation theory, are a major breakthrough in modern nuclear structure theory, since they provide a direct link between nuclear physics and its underlying theory, namely the QCD. As a matter of fact, chiral potentials are tailored on the low-energy regime of nuclear structure physics, and chiral perturbation theory provides on the same footing two-nucleon forces as well as many-body ones. This feature fits well with modern advances in ab-initio methods and realistic shell-model. Here, we will review recent nuclear structure calculations, based on realistic chiral potentials, for both finite nuclei and infinite nuclear matter.
Influence of nucleon density distribution in nucleon emission probability
International Nuclear Information System (INIS)
Paul, Sabyasachi; Nandy, Maitreyee; Mohanty, A.K.; Sarkar, P.K.; Gambhir, Y.K.
2014-01-01
Different decay modes are observed in heavy ion reactions at low to intermediate energies. It is interesting to study total neutron emission in these reactions which may be contributed by all/many of these decay modes. In an attempt to understand the importance of mean field and the entrance channel angular momentum, we study their influence on the emission probability of nucleons in heavy ion reactions in this work. This study owes its significance to the fact that once population of different states are determined, emission probability governs the double differential neutron yield
International Nuclear Information System (INIS)
Roche, G.; Koontz, R.; Mulera, T.; Pugh, H.G.; Schroeder, L.S.; Hallman, T.; Madansky, L.; Carroll, J.; Chang, C.C.; Kirk, P.N.; Krebs, G.; Vicente, J.
1985-01-01
A particle-gamma coincidence experiment has been performed with a 2.1 GeV per nucleon 12 C beam from the Bevalac. Data were taken with C and Pb targets. The γ-ray spectra are almost independent of the energy or the kind of charged particles detected in coincidence, mainly protons and deuterons. These γ-ray spectra are interpreted as resulting from π 0 decay, and are consistent with known π 0 production rates. A search for a possible decay of singly-charged anomalons into a gamma and a deuteron (or unbound proton-neutron system) has been done by studying the γp and γd invariant mass distributions. The upper limits for such a process are found to be 2 to 20% of the deuteron production rate, for anomalon masses for 200 to 400 MeV above the deuteron mass, with an anomalon mean lifetime of up to 10 -9 s, depending on which kind of decay process is considered. (orig.)
Multinucleon effects in muon capture on 3He at high energy transfer
International Nuclear Information System (INIS)
Kuhn, S.E.; Cummings, W.J.; Dodge, G.E.; Hanna, S.S.; King, B.H.; Shin, Y.M.; Congleton, J.G.; Helmer, R.; Schubank, R.B.; Stevenson, N.R.; Wienands, U.; Lee, Y.K.; Mason, G.R.; King, B.E.; Chung, K.S.; Lee, J.M.; Rosenzweig, D.P.
1994-01-01
Energy spectra of both protons and deuterons emitted following the capture of negative muons by 3 He nuclei have been measured for energies above 15 MeV. A limited number of proton-neutron pairs emitted in coincidence were also observed. A simple plane wave impulse approximation (PWIA) model calculation yields fair agreement with the measured proton energy spectra, but underpredicts the measured rate of deuteron production above our energy threshold by a large factor. A more sophisticated PWIA calculation for the two-body breakup channel, based on a realistic three-body wave function for the initial state, is closer to the deuteron data at moderate energies, but still is significantly lower near the kinematic end point. The proton-neutron coincidence data also point to the presence of significant strength involving more than one nucleon in the capture process at high energy transfer. These results indicate that additional terms in the capture matrix element beyond the impulse approximation contribution may be required to explain the experimental data. Specifically, the inclusion of nucleon-nucleon correlations in the initial or final state and meson exchange current contributions could bring calculations into better agreement with our data. A fully microscopic calculation would thus open the possibility for a quantitative test of multinucleon effects in the weak interaction
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
Institute of Scientific and Technical Information of China (English)
2012-01-01
China is putting greater emphasis on green energy as it tries to clean up industry and meet target for cuts in carbon emissions over the past two years, China has already leapfrogged competitors from Denmark, Germany, Spain and the United States to become the world＇s largest maker of wind turbines and solar panels. At the same time, the country is also taking steps to build more nuclear reactors and energy-efficient coal power plants.
Kaon Condensation in Neutron Stars and High Density Behaviour of Nuclear Symmetry Energy
International Nuclear Information System (INIS)
Kubis, S.; Kutschera, M.
1999-01-01
We study the influence of a high density behaviour of the nuclear symmetry energy on a kaon condensation in neutron stars. We find that the symmetry energy typical for several realistic nuclear potentials, which decreases at high densities, inhibits kaon condensation for weaker kaon-nucleon couplings at any density. There exists a threshold coupling above which the kaon condensate forms at densities exceeding some critical value. This is in contrast to the case of rising symmetry energy, as e.g. for relativistic mean field models, when the kaon condensate can form for any coupling at a sufficiently high density. Properties of the condensate are also different in both cases. (author)
Kaon Condensation in Neutron Stars and High Density Behaviour of Nuclear Symmetry Energy
International Nuclear Information System (INIS)
Kubis, S.; Kutschera, M.
1999-04-01
We study the influence of a high density behaviour of the nuclear symmetry energy on a kaon condensation in neutron stars. We find that the symmetry energy typical for several realistic nuclear potentials, which decreases at high densities, inhibits kaon condensation for weaker kaon-nucleon couplings at any density. There exists a threshold coupling above which the kaon condensate forms at densities exceeding some critical value. This is in contrast to the case of rising symmetry energy, as e.g. for relativistic mean field models, when the kaon condensate can form for any coupling at a sufficiently high density. Properties of the condensate are also different in both cases
Relevance of few-nucleon problems to nuclear power
International Nuclear Information System (INIS)
Divatia, A.S.
1976-01-01
It is well known that the study of few-nucleon problems did not specifically start because they were relevant to nuclear power. However, as the need for power has become more urgent and the systems which may generate nuclear power in the future are likely to be highly complex, it has become necessary to examine the question of relevance of few-nucleon problems to nuclear power. The nuclear data needs for nuclear power have been studied exhaustively by many groups all over the world and The International Atomic Energy Agency, operating through the International Nuclear Data Committee and their Nuclear Data section, have compiled and evaluated these nuclear data needs. It is therefore possible to draw upon the various studies and compilations of the IAEA for examining the question of relevance. The relevant nuclear data needs for fission reactors, fusion reactors and nuclear safeguards programmes are examined. (Auth.)
Improvements in centrifugal nucleon disintegration of CND reactors
International Nuclear Information System (INIS)
Pedrick, A.P.
1976-01-01
Reference is made to the so-called 'Centrifugal Nucleon Disintegrator Reactor' (CND) in which it is proposed to release the binding energy between nucleons of high atomic number by applying a violent spin to the nuclei. The reactor described comprises means for producing atomic nuclei that have been stripped of their electrons by heating to form a high temperature plasma. A number of laser beams are directed on to a cylinder having a polished bore and reflected therefrom so as to create tangentially a cylindrical wall or surface having a high concentration of photons moving unidirectionally, together with means for introducing nuclei into the cylindrical wall or surface of photons. A high electrostatic charge is applied to urge the nuclei against the cylindrical wall or surface. The nuclei are discharged into the space between the cylinder and the photon wall. Nucleons that have been separated from their nuclei are carried upwards in a flow of plasma, which can be arranged to produce an electrical output by interaction with an electromagnetic field. (U.K.)
The nucleon-nucleon potential in the chromodielectric soliton model
International Nuclear Information System (INIS)
Koepf, W.; Wilets, L.; Pepin, S.; Stancu, F.
1993-01-01
The short- and medium-range parts of the nucleon-nucleon interaction are being studied in the framework of the chromodielectric soliton model. The model consists of current quarks, gluons in the abelian approximation, and a scalar σ field which simulates the nonabelian interactions of the gluons and governs the medium through the dielectric function κ(σ). Absolute color confinement is effected by the vanishing of the dielectric in vacuum; this also removes the troublesome van der Waals problem. The authors distinguish between spatial confinement, which arises from the self energy of the quarks in medium (excluding MFA contributions), and color confinement which is effected through OGE in the MFA (including the corresponding self energy contributions). The static (adiabatic) energies are computed as a function of deformation (generalized bag separation) in a constrained MFA. Six quark molecular-type wave functions in all important space-spin-isospin-color configurations are included. The gluon propagator is solved in the deformed dielectric medium. The resultant Hamiltonian matrix is diagonalized. Dynamics are handled in the Generator Coordinate Method, which leads to the Hill-Wheeler integral equation. In the present case, this yields a set of coupled equations corresponding to the various configurations. Although this can be approximated by a set of differential equations, they propose to solve the integral equations with some regularization scheme
Three-nucleon forces and the trinucleon bound states
International Nuclear Information System (INIS)
Friar, J.L.; Frois, B.
1986-04-01
A summary of the bound-state working group session of the ''International Symposium on the Three-Body Force in the Three-Nucleon System'' is presented. The experimental evidence for three-nucleon forces has centered on two ground state properties: the tritium binding energy and the trinucleon form factors. Both are discussed
Energy peaks: A high energy physics outlook
Franceschini, Roberto
2017-12-01
Energy distributions of decay products carry information on the kinematics of the decay in ways that are at the same time straightforward and quite hidden. I will review these properties and discuss their early historical applications, as well as more recent ones in the context of (i) methods for the measurement of masses of new physics particle with semi-invisible decays, (ii) the characterization of Dark Matter particles produced at colliders, (iii) precision mass measurements of Standard Model particles, in particular of the top quark. Finally, I will give an outlook of further developments and applications of energy peak method for high energy physics at colliders and beyond.
Toy model for pion production in nucleon-nucleon collisions
International Nuclear Information System (INIS)
Hanhart, C.; Miller, G. A.; Myhrer, F.; Sato, T.; Kolck, U. van
2001-01-01
We develop a toy model for pion production in nucleon-nucleon collisions that reproduces some of the features of the chiral Lagrangian calculations. We calculate the production amplitude and examine some common approximations
Department of High Energy Physics: Overview
International Nuclear Information System (INIS)
Nassalski, J.
1999-01-01
Full text: The main activity of our Department is experimental high energy physics with accelerators. Experiments are carried using large facilities: - at CERN, the European Laboratory for Particle Physics in Geneva, - at Celsius Storage Ring in Uppsala and - in DESY laboratory in Hamburg, where several groups of physicists from our Department are members of international collaborations. They are listed below together with the main physics interests: At CERN - Delphi at LEP - tests of the Standard Model, b-quark physics, SUSY search, - NA48 - CP-violation in K 0 decays, rare decays, - SMC - spin dependent nucleon structure function, the Bjorken sum, - NA49 and WA98 - heavy ion physics. At CELSIUS - WASA - threshold production of light mesons, rare meson decays. At DESY - ZEUS - proton and photon structure functions, diffractive production. In most of these experiments our Department also contributed to the instrumentation of detectors and is presently involved in data collection, detector supervision and in data analysis. At the same time the Department is also involved in preparation of new experiments: - CMS (Compact Muon Solenoid) and ALICE at the LHC (Large Hadron Collider) at CERN, - COMPASS (Compact Muon and Proton Apparatus for Structure and Spectroscopy) at the SPS at CERN, - WASA-Promice - an upgrade of the present detector at Celsius, - hyperfragment experiment at JINR, Dubna. The department has small workshop which was recently involved in an upgrade of the WASA detector. In our Department there are also two physicists working on the phenomenology of a quark-gluon plasma and on the low energy hadron-hadron interactions. Physicist from our Department collaborate with the Department of the Experimental Physics of Warsaw University. They are also involved in teaching and in supervision of diploma students. There is a group of 9 PhD students. (author)
Energy Technology Data Exchange (ETDEWEB)
Cohen-Tannoudji, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1968-07-01
A phenomenological model suited for the description of arbitrary two-body reactions at high energies is presented and applied to the analysis of {pi} - nucleon, K - nucleon, et K-bar - nucleon scattering.The idea is that the Regge-pole model does not take into account the whole content of the unitarity relation and has to be modified, as is currently done in one-particle exchange models, so that it may include absorptive corrections.In terms of a rather economical set of free parameters,we obtain a satisfactory agreement with all available data, including the recent evidence for a nonvanishing polarization in {pi}{sup -} p {pi}{sup 0} n reaction. We then reinterpret our parametrization of the amplitudes in terms of poles and branch points in the complex angular-momentum plane for the crossed channel. (author) [French] Un modele phenomenologique adapte a la description des reactions a deux corps a haute energie est presente et applique a l'analyse des diffusions {pi} - nucleon, K - nucleon, et K-bar - nucleon. L'idee essentielle est que le modele d'echange de poles de Regge ne tient pas compte du contenu total de la relation d'unitarite et doit etre modifie, comme cela a ete propose dans le cas de l'echange de particules, de facon a tenir compte de corrections de type absortif. Au moyen d'un ensemble relativement economique de parametres libres nous obtenons un accord satisfaisant avec tous les resultats disponibles, y compris l'existence recemment mise en evidence d'une polarisation non nulle dans la reaction {pi}{sup -} p {pi}{sup 0} n. Nous interpretons notre fa n d'ecrire les amplitudes au moyen de poles et de points de branchement dans le plan complexe du moment angulaire pour la voie croisee. (auteur)
Pion-nucleon vertex function with one nucleon off shell
International Nuclear Information System (INIS)
Mizutani, T.; Rochus, P.
1979-01-01
The pion-nucleon vertex function with an off-mass-shell nucleon is obtained through sideways dispersion relations with the P 11 and S 11 pion-nucleon phase shifts as only input. Contrary to the recent calculation of Nutt and Shakin, we find that the proper and improper vertex functions behave quite differently, indicating the importance of the nucleon propagator dressing. In particular the proper vertex function is found to have two poles in the unphysical region
A new form for the nucleon-nucleon potential
International Nuclear Information System (INIS)
Agarwal, B.K.
1976-01-01
The form of the internucleon force is considered. It is assumed that the nucleon-nucleon potential depends, in general, both on the distance ν and the angle theta. It is also assumed that the potential V(ν,ω) admits an analytic continuation into the complex ω-plane so that when ω=costheta is real it denotes the direction in which the potential is being determined. The analysis leads to a new parametryzation of the nucleon-nucleon potential
Revision of the high energy hadronic interaction models PHOJET/DPMJET-III
Fedynitch, A
2015-01-01
The high-energy hadronic interaction model DPMJET-III is responsible for simulating nuclear interactions in the particle simulation package FLUKA. On the level of individual nucleon interactions it employs PHOJET, which provides sophisticated forward physics and diffraction models. This paper summarizes some of the recent developments, in particular regarding minimum-bias physics at the LHC, which apply to DPMJET-III and PHOJET at the same time.
Production of light fragments in hA collisions at high energies
International Nuclear Information System (INIS)
Braun, M.A.; Vechernin, V.V.
1988-12-01
Production of fast relativistic light fragments in hA collisions at high energies is considered. Direct coalescence of produced nucleons into fragments is shown to be the main mechanism for fragment production. The influence of the nuclear field is small and is not described by the well-known Butler-Pearson formulas. The coalescence coefficient strongly depends on the angle and on the behaviour of the fragment wave function at small internucleon distances. (author). 14 refs, 7 figs
Energy Technology Data Exchange (ETDEWEB)
Simula, S. [Instituto Nazionale di Fisica Nucleare, Roma (Italy)
1994-04-01
Semi-inclusive deep inelastic lepton scattering off nuclei is investigated assuming that virtual boson absorption occurs on a hadronic cluster which can be either a two-nucleon correlated pair or a six-quark bag. The differences in the energy distribution of nucleons produced in backward and forward directions are analyzed both at x<1 and x>1.
Present status of nucleon-meson transport code NMTC/JAERI
International Nuclear Information System (INIS)
Takada, H.; Meigo, S.
2001-01-01
The nucleon-meson transport code NMTC/JAM has been developed for the neutronics design study of the joint project for high-intensity proton accelerators with a power of mega-watts. The applicable energy range is extended by the inclusion of the jet AA microscopic transport model (JAM). The nucleon-nucleus cross sections are also updated for accurate transport calculation. The applicability of NMTC/JAM is studied through the analyses of thick target experiments such as neutron transmission through shield and activation reaction rate measurements. (orig.)
Nucleon Polarisabilities and Effective Field Theories
Griesshammer, Harald W.
2017-09-01
Low-energy Compton scattering probes the nucleon's two-photon response to electric and magnetic fields at fixed photon frequency and multipolarity. It tests the symmetries and strengths of the interactions between constituents, and with photons. For convenience, this energy-dependent information is often compressed into the two scalar dipole polarisabilities αE 1 and βM 1 at zero photon energy. These are fundamental quantities, and important for the proton charge radius puzzle and the Lamb shift of muonic hydrogen. Combined with emerging lattice QCD computations, they provide stringent tests for our understanding of hadron structure. Extractions of the proton and neutron polarisabilities from all published elastic data below 300 MeV in Chiral Effective Field Theory with explicit Δ (1232) are now available. This talk emphasises χEFT as natural bridge between lattice QCD and ongoing or approved efforts at HI γS, MAMI and MAX-lab. Chiral lattice extrapolations from mπ > 200 MeV to the physical point compare well to lattice computations. Combining χEFT with high-intensity experiments with polarised targets and polarised beams will extract not only scalar polarisabilities, but in particular the four so-far poorly explored spin-polarisabilities. These parametrise the stiffness of the spin in external electro-magnetic fields (nucleonic bi-refringence/Faraday effect). New chiral predictions for proton, deuteron and 3He observables show intriguing sensitivities on spin and neutron polarisabilities. Data consistency and a model-independent quantification of residual theory uncertainties by Bayesian analysis are also discussed. Proton-neutron differences explore the interplay between chiral symmetry breaking and short-distance Physics. Finally, I address their impact on the neutron-proton mass difference, big-bang nucleosynthesis, and their relevance for anthropic arguments. Supported in part by DOE DE-SC0015393 and George Washington University.
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
Theoretical interpretation of data from high-energy nuclear collisions
International Nuclear Information System (INIS)
Fai, G.
1988-09-01
Nuclear collision data at energies ranging from medium to relativistic are interpreted theoretically. The major objective is a better understanding of high-energy heavy-ion collisions, with particular emphasis on the properties of excited nuclear matter. Further progress towards a satisfactory description of excited subsaturation nuclear matter is achieved. The mean free path of a nucleon in nuclear matter, which is a critical parameter in assessing the applicability of certain nuclear collision models, is investigated. Experimental information is used together with theoretical concepts in collaborations with experimentalists in order to learn about the reaction mechanism and about excited nuclear matter properties. In the framework of a more strictly theoretical program development, subnuclear degrees of freedom and nonlinear phenomena in model field theories are studied
Meson cloud in the nucleon and its consequences in various phenomena
International Nuclear Information System (INIS)
Szczurek, A.
1997-06-01
Consequences of the meson cloud in the nucleon and search for its evidences in various phenomena in both soft and hard processes were discussed. The cut-off parameters of the form factors (FF) for meson-baryon vertices are determined from high-energy particle production data. An universal cut-off parameter for processes involving octet baryons has been found. Relativistic calculations of the effects of the pion cloud on the electromagnetic properties of the nucleon are presented. Light-cone formalism was used to construct the nucleon wave function. The elastic electromagnetic nucleon FF G p,n E (Q 2 ) and G p,n M (Q 2 ) are computed in terms of matrix elements of current operator and the nucleon wave function. The Q 2 -dependence of contributions to the nucleon FF from the various sectors of the model space is calculated. The observed deviations from FF scaling and dipole parameterization is discussed. A set of formulae for longitudinal momentum distribution functions (splitting functions) of mesons in the nucleon has been determined. The value of the Gottfried Sum Rule obtained from model (S G =0.224) agrees with that obtained by the NMC. The calculated axial coupling constants for semileptonic decays of the octet baryons agree with the experimental data. Enhanced production of events at large x in comparison to standard sets of quark distributions with rather mild Q 2 -dependence was predicted. The semi-inclusive cross section for producing slow protons in charged current deep inelastic (anti-)neutrino scattering nucleons is calculated as a function of the x and the proton momentum. The possible consequences of the meson cloud in the nucleon for the production of the W and Z bosons in hadron-hadron collisions were discussed. A good description of the total W and Z production cross sections measured in the proton-antiproton collisions as well as the lepton asymmetry have been obtained. The model predicts an enhancement of the cross section for the W production in
Meson cloud in the nucleon and its consequences in various phenomena
Energy Technology Data Exchange (ETDEWEB)
Szczurek, A. [The H. Niewodniczanski Inst. of Nuclear Physics, Cracow (Poland)
1997-06-01
Consequences of the meson cloud in the nucleon and search for its evidences in various phenomena in both soft and hard processes were discussed. The cut-off parameters of the form factors (FF) for meson-baryon vertices are determined from high-energy particle production data. An universal cut-off parameter for processes involving octet baryons has been found. Relativistic calculations of the effects of the pion cloud on the electromagnetic properties of the nucleon are presented. Light-cone formalism was used to construct the nucleon wave function. The elastic electromagnetic nucleon FF G{sup p,n}{sub E}(Q{sup 2}) and G{sup p,n}{sub M} (Q{sup 2}) are computed in terms of matrix elements of current operator and the nucleon wave function. The Q{sup 2}-dependence of contributions to the nucleon FF from the various sectors of the model space is calculated. The observed deviations from FF scaling and dipole parameterization is discussed. A set of formulae for longitudinal momentum distribution functions (splitting functions) of mesons in the nucleon has been determined. The value of the Gottfried Sum Rule obtained from model (S{sub G}=0.224) agrees with that obtained by the NMC. The calculated axial coupling constants for semileptonic decays of the octet baryons agree with the experimental data. Enhanced production of events at large x in comparison to standard sets of quark distributions with rather mild Q{sup 2}-dependence was predicted. The semi-inclusive cross section for producing slow protons in charged current deep inelastic (anti-)neutrino scattering nucleons is calculated as a function of the x and the proton momentum. The possible consequences of the meson cloud in the nucleon for the production of the W and Z bosons in hadron-hadron collisions were discussed. A good description of the total W and Z production cross sections measured in the proton-antiproton collisions as well as the lepton asymmetry have been obtained. The model predicts an enhancement of the
Parity violation in the nucleon-nucleon interaction
International Nuclear Information System (INIS)
Haxton, W.C.
1989-01-01
I discuss the present status of our understanding of parity nonconservation (PNC) in the nucleon-nucleon interaction, and some of the difficulties inherent in nuclear tests of PNC. I also discuss the nucleon/nuclear anapole moment, the parity violating coupling of the photon, and its relation to the PNC NN interaction. 13 refs., 1 fig., 2 tabs
International Nuclear Information System (INIS)
Tornow, W.; Howell, C.R.; Walter, R.L.; Slaus, I.
1992-01-01
Comparison of data for neutron-deuteron and proton-deuteron analyzing power A y for elastic scattering has become crucial for investigating charge-symmetry breaking in the 3 P nucleon-nucleon interactions. We extended this comparison down to 5 MeV and find that the relative difference between n-d and p-d scattering at the A y maximum near 120 degree increases with decreasing energy. By applying a straightforward Coulomb ''correction'' to the p-d data, we account for most of the difference, suggesting that the Coulomb force, rather than charge-symmetry breaking, is responsible for most of the observed difference
International Nuclear Information System (INIS)
Grange, P.; Mathiot, J.F.; Roy-Stephan, M.; Frascaria, R.; Gales, S.
1990-01-01
The topics presented at the 1989 Joliot-Curie Lectures are reported. Two main subjects were retained: a simplified description of the N-body motion of particles in the quasi-particle configuration; study of the dynamics of nuclear components which are not described by nucleons in their ground state. The following themes were presented: quasiparticles and the Green functions, relativistic aspects of the quasiparticle concept, the dimensions of nucleons in the nuclei and the EMC effect, quarks and gluons in the nuclei, the delta in the nuclei, the strangeness, quasiparticles far from the Fermi sea, diffusion of electrons, stellar evolution and nucleosynthesis [fr
International Nuclear Information System (INIS)
Virchaux, M.
1992-11-01
The present status of experimental measurements of the nucleon structure functions is reviewed. The results from nearly all deep inelastic experiments are in good mutual agreement. Principles of the analysis of these structure function data in the framework of QCD are described. The specific features of the perturbative QCD predictions are observed in the data. This provides quantitative tests of the validity of QCD as well as determinations of the various parton distributions in the nucleon and some of the most precise measurements of the strong coupling constant αs. The future of this field of experimental physics is sketched
Nucleon strangeness: present and future
Sapozhnikov, M G
2010-01-01
A review of experimental results for the measurement of the strange quark distributions in the nucleon, is given. Contributions of the strange quarks to the nucleon mass, electromagnetic form factors and spin, are discussed.
JACEE results on very high energy interactions
International Nuclear Information System (INIS)
Wilczynski, H.
1996-01-01
Direct observations of cosmic ray interactions in emulsion chambers of the JACEE experiment at energies above 1 TeV/nucleon are presented. An analysis of two decay of short lived particles produced in cosmic ray interactions is described. The known decay modes of bottom and charged particles do not account satisfactorily for the observations. This could possibly indicate a new decay channel of a heavy particle. The JACEE results support the hypothesis of existence of a long-flying component in cosmic ray showers. An interaction event was observed which may be the first direct observation of (mini)anticentauro interaction. (author)
Spallation integral experiment analysis by high energy nucleon-meson transport code
Energy Technology Data Exchange (ETDEWEB)
Takada, Hiroshi; Meigo, Shin-ichiro; Sasa, Toshinobu; Fukahori, Tokio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yoshizawa, Nobuaki; Furihata, Shiori; Belyakov-Bodin, V.I.; Krupny, G.I.; Titarenko, Y.E.
1997-03-01
Reaction rate distributions were measured with various activation detectors on the cylindrical surface of the thick tungsten target of 20 cm in diameter and 60 cm in length bombarded with the 0.895 and 1.21 GeV protons. The experimental results were analyzed with the Monte Carlo simulation code systems of NMTC/JAERI-MCNP-4A, LAHET and HERMES. It is confirmed that those code systems can represent the reaction rate distributions with the C/E ratio of 0.6 to 1.4 at the positions up to 30 cm from beam incident surface. (author)
[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
Shielding experiments with high-energy heavy ions for spaceflight applications
Energy Technology Data Exchange (ETDEWEB)
Zeitlin, C; Guetersloh, S; Heilbronn, L; Miller, J [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Elkhayari, N; Empl, A; LeBourgeois, M; Mayes, B W; Pinsky, L [Physics Department, University of Houston, Houston, TX (United States); Christl, M [NASA Marshall Spaceflight Center, Huntsville, AL (United States); Kuznetsov, E [Physics Department, University of Alabama, Huntsville, AL (United States)], E-mail: cjzeitlin@lbl.gov
2008-07-15
Mitigation of radiation exposures received by astronauts on deep-space missions must be considered in the design of future spacecraft. The galactic cosmic rays (GCR) include high-energy heavy ions, many of which have ranges that exceed the depth of shielding that can be launched in realistic scenarios. Some of these ions are highly ionizing (producing a high dose per particle) and for some biological endpoints are more damaging per unit dose than sparsely ionizing radiation. The principal physical mechanism by which the dose and dose equivalent delivered by these particles can be reduced is nuclear fragmentation, the result of inelastic collisions between nuclei in the hull of the spacecraft and/or other materials. These interactions break the incident ions into lighter, less ionizing and less biologically effective particles. We have previously reported the tests of shielding effectiveness using many materials in a 1 GeV nucleon{sup -1} {sup 56}Fe beam, and also reported results using a single polyethylene (CH{sub 2}) target in a variety of beam ions and energies up to 1 GeV nucleon{sup -1}. An important, but tentative, conclusion of those studies was that the average behavior of heavy ions in the GCR would be better simulated by heavy beams at energies above 1 GeV nucleon{sup -1}. Following up on that work, we report new results using beams of {sup 12}C, {sup 28}Si and {sup 56}Fe, each at three energies, 3, 5 and 10 GeV nucleon{sup -1}, on carbon, polyethylene, aluminium and iron targets.
International Nuclear Information System (INIS)
Chiba, Satoshi; Niita, Koji; Maruyama, Toshiki; Fukahori, Tokio; Takada, Hiroshi; Iwamoto, Akira
1995-01-01
The double-differential (p,xp') and (p,xn) reaction cross sections of 58 Ni and 90 Zr in the energy range from 120 to 200 MeV have been studied in terms of the Quantum Molecular Dynamics. It was found that the present calculation could give a quantitative explanation of experimentally observed values of both channels simultaneously without adjusting any parameter, showing the usefulness of the QMD approach to study the pre-equilibrium process in this energy region. Comparisons were also made with prediction of other theories such as Antisymmetrized Molecular Dynamics (AMD) and semiclassical distorted wave theory. Effect of the anti-symmetrization, which is in AMD but not in QMD, was found surprisingly small, being the result of QMD even slightly better. At the same time, it was found that the present calculation does not give the quasi-free peak of the 1-step cross sections similar to the semiclassical model, due probably to different treatment of the refraction and acceleration effects caused by the mean field. (author)
Interactions of 82Pb208 nuclei with energy 158 GeV per nucleon with photoemulsion nuclei
International Nuclear Information System (INIS)
Adamovich, M.I.; Andreeva, N.P.; Bubnov, V.I.; Gajtinov, A.Sh.; Kanygina, Eh.K.; Musaeva, A.K.; Sejtimbetov, A.M.; Skorobagatova, V.I.; Filippova, L.N.; Chasnikov, I.Ya.
1999-01-01
In this report there are experimental data on 82 Pb 208 nuclei (158 GeV) interaction with photoemulsion nuclei. The said data are compared to the similar ones for 79 Au 197 nuclei with less energy (10,7 A GeV). Stack of nuclear emulsion was irradiated with the beam of nuclei 82 Pb 208 at SPS of CERN. Events search was done along the primary nucleus trace. Pb nucleus average path length happened to be λ=(3,8±0,1) cm, this virtually coincides with the one calculated by Brandt and Peters formula (3,9 cm). Secondary particles were identified into s (storm), g (knock-on protons) and b- particles (target nucleus fragments), as well as into nucleus-bullet fragments with different charges (Z=1,2,≥3). This allowed obtaining event distribution by multiplicity of these particles (n s , n g , n b ) and fragments (n z=1,2,≥3 ), calculation of average values by multiplicity (see table), finding correlation of characteristics. >From the table it's clear that when the energy increases s > increases 2,5 times where as g > insignificantly decreases and b > doesn't change
Systematic of fusion incompleteness in 20Ne induced reactions at energy 4-7 MeV/nucleon
International Nuclear Information System (INIS)
Ali, Sabir; Ahmad, Tauseef; Kumar, Kamal
2016-01-01
In the present work, a study of fusion incompleteness using the 20 Ne projectile over 51 V, 55 Mn and 59 Co and targets has been carried out. The experiment involving 20 N e+ 51 V system was performed at VECC, Kolkata, India. The targets of thickness range 1.19-1.50 rug/cm 2 of spectroscopically pure 51 V (purity 99.99%) were prepared by depositing on aluminum backing of thickness range 1.47-1.64 mg/cm 2 by the vacuum evaporation technique at the target lab of VECC. A stack of six 51 V targets was irradiated for ≈ 11 hrs by 20 Ne 6+ beam at ≈145 MeV. The irradiation of the stack covered the desired energy range of 82-145 MeV. The beam current was ≈ 40 nA during the irradiation hours. The energy of the 20 Ne ion beam incident on each target foil was calculated using stopping power software SRIM. The overall error in the present work is estimated to be ≤20%
High energy cosmic ray astronomy
International Nuclear Information System (INIS)
Fonseca, V.
1996-01-01
A brief introduction to High Energy Cosmic Ray Astronomy is presented. This field covers a 17 decade energy range (2.10 4 -10 20 ) eV. Recent discoveries done with gamma-ray detectors on-board satellites and ground-based Cherenkov devices are pushing for a fast development of new and innovative techniques, specially in the low energy region which includes the overlapping of satellite and ground-based measurements in the yet unexplored energy range 20 keV-250 GeV. Detection of unexpected extremely high energy events have triggered the interest of the international scientific community. (orig.)
Nucleus-Nucleus Scattering in the High-Energy Approximation and the Optical Folding Potential
Lukyanov, V K; Lukyanov, K V
2004-01-01
For the nucleus-nucleus scattering, the complex potential is obtained which corresponds to the eikonal phase of an optical limit of the Glauber-Sitenko high-energy approximation. The potential does not include free parameters, its real and imaginary parts depend on energy and are determined by the reported data on the nuclear density distributions and nucleon-nucleon scattering amplitude. Alternatively, for the real part, the folding potential can be utilized which includes the effective NN-forces and the exchange term, as well. As a result, the microscopic optical potential is constructed where contributions of the calculated real and imaginary parts are formed by fitting the two respective factors. An efficient of the approach is confirmed by agreements of calculations with the experimental data on elastic scattering cross-sections.
Light hypernuclei and hyperon-nucleon interaction
International Nuclear Information System (INIS)
Carlson, J.; Gibson, B.F.
1990-01-01
Light Hypernuclei are a vital testing ground for our understanding of the Hyperon-Nucleon interaction. We have performed microscopic calculations of four and five-body hypernuclei using the Nijmegen nucleon-nucleon and hyperon-nucleon interactions. Our calculations include explicit Sigma degrees of freedom. These degrees of freedom are quite important since, in contrast to the Δ - N mass difference of ∼ 300 MeV, the Σ resonance is only about 80 MeV above the Λ. In addition, although there is no one-pion-exchange in the ΛN diagonal channel, this longest-range term does contribute to the transition ΛN - ΣN interaction. Our variational calculations show that the A=4 spin 0 ground state binding energy is well reproduced by the Nijmegen HN integration, a one-boson exchange model fit to the available scattering data. The spin 1 excited state and the A=5 ground state are strongly underbound, however. We demonstrate the importance of the strong tensor terms of the Nijmegen model, particularly those in the transition channel, in obtaining this result. The limited data currently available for hyperon-nucleon scattering must be greatly improved in order to place reasonable constraints on the interaction. 12 refs., 3 figs., 3 tabs
Light hypernuclei and hyperon-nucleon interaction
Energy Technology Data Exchange (ETDEWEB)
Carlson, J.; Gibson, B.F.
1990-01-01
Light Hypernuclei are a vital testing ground for our understanding of the Hyperon-Nucleon interaction. We have performed microscopic calculations of four and five-body hypernuclei using the Nijmegen nucleon-nucleon and hyperon-nucleon interactions. Our calculations include explicit Sigma degrees of freedom. These degrees of freedom are quite important since, in contrast to the {Delta} {minus} N mass difference of {approx} 300 MeV, the {Sigma} resonance is only about 80 MeV above the {Lambda}. In addition, although there is no one-pion-exchange in the {Lambda}N diagonal channel, this longest-range term does contribute to the transition {Lambda}N {minus} {Sigma}N interaction. Our variational calculations show that the A=4 spin 0 ground state binding energy is well reproduced by the Nijmegen HN integration, a one-boson exchange model fit to the available scattering data. The spin 1 excited state and the A=5 ground state are strongly underbound, however. We demonstrate the importance of the strong tensor terms of the Nijmegen model, particularly those in the transition channel, in obtaining this result. The limited data currently available for hyperon-nucleon scattering must be greatly improved in order to place reasonable constraints on the interaction. 12 refs., 3 figs., 3 tabs.
Binary projectile fragmentation of 12C at an incident energy of 33.3 MeV/nucleon
Förtsch, S V; Gadioli, E; Bassini, R; Buthelezi, E Z; Cerutti, F; Connell, S H; Cowley, A A; Fujita, H; Mabiala, J; Mairani, A; Mira, J; Papka, P; Neveling, R; Smit, F D
2010-01-01
Direct binary projectile fragmentation is being investigated for the case where a 400 MeV 12C projectile breaks up into an particle and a 8Be fragment in the interaction with a thin 93Nb and 197Au target. While the 8Be fragments were measured at 9 , the correlated particles were detected in an angular range between 16 and 30 on the opposite side of the beam. From the preliminary results presented here one may obtain information on the amount of quasi-elastic fragmentation (both fragments do not suffer any further interactions after they are produced). These experimental results indicate that the quasi-elastic break-up process is the dominant contribution to the measured correlation spectra. As was also observed in earlier work, the most forward quasi-elastically emitted particles have energies exceeding the beam velocity.
Nucleon-induced reactions at intermediate energies: new data at 96 MeV and theoretical status
Energy Technology Data Exchange (ETDEWEB)
Blideanu, V.; Lecolley, F.R.; Lecolley, J.F.; Lefort, T.; Marie, N.; Ban, G.; Louvel, M. [Caen Univ., Lab. de Physique Corpusculaire, ENSICAEN, IN2P3-CNRS ISMRA, 14 (France); Atac, A.; Bergenwall, B.; Blomgren, J.; Dangtip, S.; Hildebrand, A.; Hohansson, C.; Klug, J.; Nilsson, L.; Ollson, N.; Pomp, S.; Tippawan, U.; Osterlund, M. [Uppsala Univ., Nykoeping (Sweden). Dept. of Neutron Research; Tippawan, U. [Chiang Mai University, Fast Neutron Research Facility (Thailand); Elmgren, K.; Olsson, N. [Swedish Defense Research Agency, Stokholm (Sweden); Eudes, Ph.; Guertin, A.; Haddad, F.; Kirchner, T.; Lebrun, C.; Riviere, G. [Nantes Univ., Subatech, 44 (France); Foucher, Y. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Jonsson, O.; Prokofiev, A.V.; Renberg, P.U. [Uppsala Univ., Svedberg Laboratory (Sweden); Kerveno, M.; Stuttge, L. [IReS, Strasbourg (France); Le Brun, Ch. [Laboratoire de Physique Subatomique et de Cosmologie, 38 - Grenoble (France); Nadel-Turonski, P. [Uppsala Univ. (Sweden). Dept. of Radiation Sciences; Slypen, I. [Universite Catholique de Louvain (UCL), Institut de Physique Nucleaire, Louvain-la-Neuve (Belgium)
2004-04-01
Double-differential cross sections for light charged particle production (up to A = 4) were measured in 96 MeV neutron-induced reactions, at TSL laboratory cyclotron in Uppsala (Sweden). Measurements for three targets, Fe, Pb, and U, were performed using two independent devices, SCANDAL and MEDLEY. The data were recorded with low energy thresholds and for a wide annular range (20 - 160 degrees). The normalization procedure used to extract the cross sections is based on the np elastic scattering reaction that we measured and for which we present experimental results. A good control of the systematic uncertainties affecting the results is achieved. Calculations using the exciton model are reported. Two different theoretical approaches proposed to improve its predictive power regarding the complex particle emission are tested. The capabilities of each approach is illustrated by comparison with the 96 MeV data that we measured, and with other experimental results available in the literature. (authors)
Indian Academy of Sciences (India)
IAS Admin
Propellants used in rockets, pyrotechnics used in festivities, explosives used for .... In World War II, Wernher von Braun designed the. V-2 rockets which were ... A. Solid Propellants. A solid propellant is made from low or diluted high explosives.
Impact of nucleon mass shift on the freeze-out process
International Nuclear Information System (INIS)
Zschocke, Sven; Csernai, Laszlo Pal; Molnar, Etele; Nyiri, Agnes; Manninen, Jaakko
2005-01-01
The freeze-out of a massive nucleon gas through a finite layer with a timelike normal is studied. The impact of the in-medium nucleon mass shift on the freeze-out process is investigated. A considerable modification of the thermodynamic variables of temperature, flow velocity, energy density, and particle density has been found. Because of the nucleon mass shift the freeze-out particle distribution functions are changed noticeably in comparison with the evaluations, which use the vacuum nucleon mass
Effective lagrangian for Kaon-nucleon scattering
International Nuclear Information System (INIS)
Andrade, S.C.B. de; Ferreira, E.M.
1980-11-01
A model for the Kaon-nucleon interaction is investigated, based on a lagrangian which includes the Yukawa interactions of hyperons, kaons and nucleons plus contact terms representing short range interactions in each isospin state. All diagrams up to fourth order are evaluated and the partial wave S matrix elements are unitarized through diagonal Pade approximants. The results of the calculations with this model give a good description of all experimental data on both I = O and I = 1 states of the KN system at low and intermediate energies. (Author) [pt
Composite nucleon approach to the deuteron problem
International Nuclear Information System (INIS)
Agarwal, B.K.
1975-01-01
A composite model is suggested for the nucleons by assuming a long-range strong gluon force between a diquark boson B and a quark A. In the proton, A is trapped inside B in an oscillator potential; and in the neutron, A is on the surface of B in a hydrogenlike state. Nucleon form factors are obtained in agreement with experiments. The model contains a mechanism for a large effective mass of the quark A. When B is identified with π and A with μ, one can fix the gluon charge value and obtain the magnetic moments of the proton and neutron. The (μπ) atomic model for the nucleon can be used to construct the deuteron on a hydrogen molecule model. It leads to values for the binding energy, electric quadrupole moment, and form factors of the deuteron that are in agreement with experiments
Computing in high energy physics
International Nuclear Information System (INIS)
Watase, Yoshiyuki
1991-01-01
The increasingly important role played by computing and computers in high energy physics is displayed in the 'Computing in High Energy Physics' series of conferences, bringing together experts in different aspects of computing - physicists, computer scientists, and vendors
International Nuclear Information System (INIS)
Windmolders, R.
1989-01-01
In this paper the following topics are reviewed: 1. the structure functions measured in deep inelastic e-N, μ-N and ν-N scattering; 2. nuclear effects on the structure functions; 3. nuclear effects on the fragmentation functions; 4. the spin dependent structure functions and their interpretation in terms of nucleon constituents. (orig./HSI)
Nowak, M A; Zahed, I
1989-01-01
The issue of the strangeness content of the proton in relation to a large σ π N term is examined using the instanton-antiinstanton description of the QCD ground state. Modulo plausible assumptions, our results indicate no strangeness admixture in the nucleon state at zero momentum transfer.
International Nuclear Information System (INIS)
Anon.
1978-01-01
The design and operation of a nucleonic weighing machine fabricated for continuous weighing of material over conveyor belt are described. The machine uses a 40 mCi cesium-137 line source and a 10 litre capacity ionization chamber. It is easy to maintain as there are no moving parts. It can also be easily removed and reinstalled. (M.G.B.)
Charge and energy dependence of the residence time of cosmic ray nuclei below 15 GeV/nucleon
International Nuclear Information System (INIS)
Soutoul, A.; Engelmann, J.J.; Ferrando, P.; Koch-Miramond, L.; Masse, P.; Webber, W.R.
1985-01-01
The relative abundance of nuclear species measured in cosmic rays at Earth has often been interpreted with the simple leaky box model. For this model to be consistent an essential requirement is that the escape length does not depend on the nuclear species. The discrepancy between escape length values derived from iron secondaries and from the B/C ratio was identified by Garcia-Munoz and his co-workers using a large amount of experimental data. Ormes and Protheroe found a similar trend in the HEAO data although they questioned its significance against uncertainties. They also showed that the change in the B/C ratio values implies a decrease of the residence time of cosmic rays at low energies in conflict with the diffusive convective picture. These conclusions crucially depend on the partial cross section values and their uncertainties. Recently new accurate cross sections of key importance for propagation calculations have been measured. Their statistical uncertainties are often better than 4% and their values significantly different from those previously accepted. Here, these new cross sections are used to compare the observed B/C+O and (Sc to Cr)/Fe ratio to those predicted with the simple leaky box model
International Nuclear Information System (INIS)
Krebs, H.; Epelbaum, E.; Meissner, U.G.
2007-01-01
We study the two-nucleon force at next-to-next-to-leading order in a chiral effective field theory with explicit Δ degrees of freedom. Fixing the appearing low-energy constants from a next-to-leading-order calculation of pion-nucleon threshold parameters, we find an improved convergence of most peripheral nucleon-nucleon phases compared to the theory with pions and nucleons only. In the delta-full theory, the next-to-leading-order corrections are dominant in most partial waves considered. (orig.)
Nucleon-nucleon correlations in dense nuclear matter
International Nuclear Information System (INIS)
Alm, T.
1993-02-01
In this thesis new results on the problematics of the formation of nucleon-nucleon correlations in nuclear matter could be presented. Starting from a general study of the two-particle problem in matter we studied the occurrence of a suprafluid phase (pair condensate of nucleons). The Gorkov decoupling by means of anomalous Green functions was generalized, so that also Cooper pairs with spin 1 (triplet pairing) can be described. A generalized gap equation resulted, which permits to determine the order parameters of the suprafluied phase in arbitrary channels of the nucleon-nucleon scattering states. This equation was solvd in the 1 S 0 -, in the 3 P 2 - 3 F 2 , and in the 3 S 1 - 3 D 1 channel under application of realistic nucleon-nucleon potentials. The behaviour of the resulting gap parameters in the single channels was studied as function of density and temperature. (orig.) [de
CERN Communication Group
2015-01-01
On Wednesday at 10.40 a.m., the LHC operators declared “stable beams” after two years of technical stop and a few months of commissioning. It was an exciting day for all the teams involved, including those who worked on communicating the news to the public and the media on multiple platforms. CERN’s most successful tweet on 3 June featured collision images from ALICE, ATLAS, CMS and LHCb and was shared 800 times by the Twitter audience. Live blogging, social media posts, a live webcast, and a constant outpouring of photos and videos: Wednesday morning was a crazy time for the communication teams from CERN, the experiments and various institutes around the world. Even though the event started very early in the morning (the live CCC blog started at 7 a.m. and the live webcast at 8.20 a.m.), the public and the media tuned in to follow and generously cover the start of the LHC’s physics run at an unprecedented energy of 13 TeV. The statistics showed th...
Energy Technology Data Exchange (ETDEWEB)
Gaisser, Thomas K. [Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)]. E-mail: gaisser@bartol.udel.edu; Stanev, Todor [Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States)
2006-10-17
After a brief review of galactic cosmic rays in the GeV to TeV energy range, we describe some current problems of interest for particles of very high energy. Particularly interesting are two features of the spectrum, the knee above 10{sup 15} eV and the ankle above 10{sup 18} eV. An important question is whether the highest-energy particles are of extra-galactic origin and, if so, at what energy the transition occurs. A theme common to all energy ranges is use of nuclear abundances as a tool for understanding the origin of the cosmic radiation.
International Nuclear Information System (INIS)
Watson, A.A.
1986-01-01
Cosmic radiation was discovered 70 years ago but its origin remains an open question. The background to this problem is outlined and attempts to discover the origin of the most energetic and rarest group above 10 15 eV are described. Measurements of the energy spectrum and arrival direction pattern of the very highest energy particles, mean energy about 6 x 10 19 eV, are used to argue that these particles originate outside our galaxy. Recent evidence from the new field of ultra high energy γ-ray astronomy are discussed in the context of a galactic origin hypothesis for lower energy cosmic rays. (author)
International Nuclear Information System (INIS)
Kernan, A.; Shen, B.C.; Ma, E.
1997-01-01
Hadron collider studies will focus on: (i) the search for the top quark with the newly installed D0 detector at the Fermilab Tevatron collider, (ii) the upgrade of the D0 detector to match the new main injector luminosity and (iii) R ampersand D on silicon microstrip tracking devices for the SSC. High statistics studies of Z 0 decay will continue with the OPAL detector at LEP. These studies will include a direct measurement of Z decay to neutrinos, the search for Higgs and heavy quark decays of Z. Preparations for the Large Scintillation Neutrino Detector (LSND) to measure neutrino oscillations at LAMPF will focus on data acquisition and testing of photomultiplier tubes. In the theoretical area E. Ma will concentrate on mass-generating radiative mechanisms for light quarks and leptons in renormalizable gauge field theories. J. Wudka's program includes a detailed investigation of the magnetic-flip approach to the solar neutrino
One-boson-exchange approach to dilepton production in nucleon-nucleon collisions
International Nuclear Information System (INIS)
Haglin, K.L.
1991-01-01
The author calculates energy-dependent nucleon-nucleon elastic cross sections and electron-positron pair production differential cross sections for the processes pp → pp, np → np, and pp → ppe + e - , np → npe + e - at laboratory kinetic energies in the 1-5 GeV range. These calculations will be based on a one-boson-exchange (π, ρ, ω, σ, δ, η) approximation to the nucleon-nucleon scattering problem. Strong form factors are included in a manner which preserves gauge invariance. He finds excellent results as compared with data for the total elastic cross sections. The calculate differential elastic cross sections show only qualitative agreement with data. For dilepton production in n-p scattering the model overestimates the number of pairs as compared with proton on beryllium data. For the p-p case he finds the tensor coupling of the ρ to the nucleons to be clearly dominant. Data do not yet exist for the p-p case at these energies: the author predicts them
International Nuclear Information System (INIS)
Piroue, P.A.
1992-10-01
The goal of this research is to understand the fundamental constituents of matter and their interactions. At this time, the following activities are underway: e + e - interactions and Z 0 physics at CERN; studies to upgrade the L3 detector at LHC; very high statistics charm physics at Fermilab; search for the H particle at BNL; search for the fifth force; rare kaon decay experiments at BNL; study of B-meson physics at hadron colliders; e + e - pair creation by light at SLAC; R ampersand D related to SSC experiments and the GEM detector; and theoretical research in elementary particle physics and cosmology. The main additions to the activities described in detail in the original grant proposal are (1) an experiment at SLAC (E-144) to study strong-field QED effects in e-laser and γ-laser collisions, and (2) a search for the H particle at BNL (E-188). The R ampersand D efforts for the GEM detector have also considerably expanded. In this paper we give a brief status report for each activity currently under way
International Nuclear Information System (INIS)
1992-01-01
The Counter Group continues to work on data analysis for Fermilab Experiment E653. Altogether, they expect several thousand reconstructed charm events and approximately 25 B pair events of which 12 have been observed thus far. Preparation continue for Fermilab Experiment E781, a high statistics study of charm baryon production. In the Theory Group, Cutkosky and collaborators study hadron phenomenology and non-perturbative QCD calculations. Levine has a long standing program in computational QED to obtain improved theoretical values for g-2 of the electron. Wolfenstein, Li, and their collaborators have worked on areas of weak interaction phenomenology that may yield insights beyond the standard model, e.g. CP violation and non-zero neutrino masses. Holman has been concerned with phase transitions in gauge theories relevant to cosmological problems. During 1991 most of the group effort was concentrated on the L3 experiment at CERN. Highlights of the results from the analysis of the Z degrees resonance include (a) a measurement of the strong coupling constant α s for b quarks (b) a precision measurement of the average time of B hadrons and (c) a direct determination of the number of light neutrino faculties from the reaction e + e - → ν bar νγ. We also began a major upgrade of the L3 luminosity monitor by replacing PWC chamber by a Si strip system in front of the BGO calorimeters. Finally we have continued our SSC R ampersand D work on BaF 2 by joining the GEM collaboration
International Nuclear Information System (INIS)
Alsmiller, F.S.; Alsmiller, R.G. Jr.; Hermann, O.W.
1987-01-01
The high-energy hadron-nucleus collision model, EVENTQ, has been modified to include a calculation of the excitation and kinetic energy of the residual compound nucleus. The specific purpose of the modification is to make it possible to use the model in the high-energy radiation transport code, HETC, which, in conjunction with MORSE, is used to transport the low energy particles. It is assumed that the nucleons in the nucleus move in a one-dimensional potential well and have the momentum distribution of a degenerate Fermi gas. The low energy particles produced by the deexcitation of the residual compound nucleus, and the final residual nucleus, are determined from an evaporation model. Comparisons of multiplicities and residual nuclei distributions with experimental data are given. The ''grey'' particles, i.e., charged particles with 0.25 < β < 0.7, are in good agreement with experimental data but the residual nuclei distributions are not. 12 refs., 3 figs
International Nuclear Information System (INIS)
Sadler, M.E.; Isenhower, L.D.
1990-01-01
This report discusses the following: pion-nucleon program; a search for neutral pions from the spontaneous fission of 252 Cf; elastic and inelastic pion scattering on 3 H and 3 He; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral B mesons; measurement of π - p → π 0 n in the cusp region at the Leningrad Nuclear Physics Institute (LNPI); a test of consistency of low-energy pion-nucleon differential cross sections with total cross sections; and design of a high energy photon calorimeter for the neutral meson spectrometer
Conference on High Energy Physics
2016-01-01
Conference on High Energy Physics (HEP 2016) will be held from August 24 to 26, 2016 in Xi'an, China. This Conference will cover issues on High Energy Physics. It dedicates to creating a stage for exchanging the latest research results and sharing the advanced research methods. HEP 2016 will be an important platform for inspiring international and interdisciplinary exchange at the forefront of High Energy Physics. The Conference will bring together researchers, engineers, technicians and academicians from all over the world, and we cordially invite you to take this opportunity to join us for academic exchange and visit the ancient city of Xi’an.