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

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

In-medium QCD sum rules for {omega} meson, nucleon and D meson

Energy Technology Data Exchange (ETDEWEB)

Thomas, Ronny

2008-07-01

The modifications of hadronic properties caused by an ambient nuclear medium are investigated within the scope of QCD sum rules. This is exemplified for the cases of the {omega} meson, the nucleon and the D meson. By virtue of the sum rules, integrated spectral densities of these hadrons are linked to properties of the QCD ground state, quantified in condensates. For the cases of the {omega} meson and the nucleon it is discussed how the sum rules allow a restriction of the parameter range of poorly known four-quark condensates by a comparison of experimental and theoretical knowledge. The catalog of independent four-quark condensates is covered and relations among these condensates are revealed. The behavior of four-quark condensates under the chiral symmetry group and the relation to order parameters of spontaneous chiral symmetry breaking are outlined. In this respect, also the QCD condensates appearing in differences of sum rules of chiral partners are investigated. Finally, the effects of an ambient nuclear medium on the D meson are discussed and relevant condensates are identified. (orig.)

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

Isospin-dependent properties of asymmetric nuclear matter in relativistic mean-field models

OpenAIRE

Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An

2007-01-01

Using various relativistic mean-field models, including the nonlinear ones with meson field self-interactions, those with density-dependent meson-nucleon couplings, and the point-coupling models without meson fields, we have studied the isospin-dependent bulk and single-particle properties of asymmetric nuclear matter. In particular, we have determined the density dependence of nuclear symmetry energy from these different relativistic mean-field models and compare the results with the constra...

Meson-baryon coupling constants from a chiral-invariant SU(3) Lagrangian and application to NN scattering

International Nuclear Information System (INIS)

Stoks, V.G.J.

1997-01-01

We present a chiral-invariant meson-baryon Lagrangian which describes the interactions of the baryon octet with the lowest-mass meson nonets. The nonlinear realization of the chiral symmetry generates pair-meson interaction vertices. The corresponding pair-meson coupling constants can all be expressed in terms of the meson-nucleon-nucleon pseudovector, scalar, and vector coupling constants, and their corresponding F/(F+D) ratios, and for which empirical estimates are given. We show that it is possible to construct an NN potential of reasonable quality satisfying these theoretical and empirical constraints. (orig.)

Finite Nuclei in the Quark-Meson Coupling Model.

Science.gov (United States)

Stone, J R; Guichon, P A M; Reinhard, P G; Thomas, A W

2016-03-04

We report the first use of the effective quark-meson coupling (QMC) energy density functional (EDF), derived from a quark model of hadron structure, to study a broad range of ground state properties of even-even nuclei across the periodic table in the nonrelativistic Hartree-Fock+BCS framework. The novelty of the QMC model is that the nuclear medium effects are treated through modification of the internal structure of the nucleon. The density dependence is microscopically derived and the spin-orbit term arises naturally. The QMC EDF depends on a single set of four adjustable parameters having a clear physics basis. When applied to diverse ground state data the QMC EDF already produces, in its present simple form, overall agreement with experiment of a quality comparable to a representative Skyrme EDF. There exist, however, multiple Skyrme parameter sets, frequently tailored to describe selected nuclear phenomena. The QMC EDF set of fewer parameters, derived in this work, is not open to such variation, chosen set being applied, without adjustment, to both the properties of finite nuclei and nuclear matter.

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

Charge dependence of the pion-nucleon coupling constant

Directory of Open Access Journals (Sweden)

V. A. Babenko

2015-07-01

Full Text Available On the basis of the Yukawa potential we study the pion-nucleon coupling constants for the neutral and charged pions assuming that nuclear forces at low energies are mainly determined by the exchange of virtual pions. We obtain the charged pseudovector pion-nucleon coupling constant f2π± = 0.0804(7 by making the use of experimental low-energy scattering parameters for the singlet pp- and np-scattering, and also by use of the neutral pseudovector pion-nucleon coupling constant f2π0 = 0.0749(7. Corresponding value of the charged pseudoscalar pion-nucleon coupling constant g2π0 / 4π = 14.55(13 is also determined. This calculated value of the charged pseudoscalar pion-nucleon coupling constant is in fully agreement with the experimental constant g2π0 / 4π = 14.52(26 obtained by the Uppsala Neutron Research Group. Our results show considerable charge splitting of the pion-nucleon coupling constant.

Effective nucleon-nucleon interaction in the RPA

International Nuclear Information System (INIS)

Batista, E.F.; Carlson, B.V.; Conti, C. de; Frederico, T.

2001-01-01

The purpose of the present work is to study the properties of the effective nucleon-nucleon interaction, in a infinite system of mesons and baryons , using the relativistic Hartree-Fock-Bogoliubov approximation. To derive the RHFB equations in a systematic fashion, we use Dyson's equation to sum to all orders the self-consistent tadpole and exchange contributions to the extended baryon Green's function (the Gorkov propagator). The meson propagator is computed as a sum over ring diagrams which consist in repeated insertions of the lowest-order proper polarization graph. The sum is the diagrammatic equivalent of the relativistic random phase approximation (RPA) that describes the well-known collective modes. In the nuclear medium, the σ and ω propagators are linked because of scalar-vector mixing, a density-dependent effect that generates a coupling between the Dyson's equation for the meson propagators. We use the dressed meson propagator to obtain the effective interaction and investigate its effect on the 1 S 0 pairing in nuclear matter. The effective interaction has title effect on the self-energy mean field, since the latter is dominated by the Hartree contribution, which is determined by the free meson propagators. The pairing field, however, is obtained from an exchange term, in which the effective interaction can play an important role. As the polarization corrections to the meson propagators tend to increase the σ-meson mass and decrease the ω-meson mass, they result in an effective interaction which is more repulsive than the bare one. We would expect this to result in a decrease in the 1 S 0 pairing, similar to that seen in nonrelativistic calculations. (author)

Muoproduction of J/ψ-mesons and the gluon distribution in nucleons

International Nuclear Information System (INIS)

Jong, Maarten de.

1991-01-01

The cross sections for production of J/ψ-mesons in muon-scattering at hydrogen and deuterium have been measured at a muon-energy of 280 GeV in order to extract from these the momentum distribution of gluons in the nucleon. These cross sections turned out to be equal for protons and neutrons within the experimental error. In the framework of the colour singlet model the gluon distribution has been determined from the cross section for the inelastic production of J/ψ mesons. At small gluon impulses the distribution obtained resembles a brems-strahlung spectrum. This distribution decreases, according to a simple description (counting rules) at larger impulses. The same model however underestimates the cross section for elastic production of J/ψ-mesons seriously. It is found that in inelastic production of J/ψ-mesons both helicities of the meson occur equally. Also a correlation has been observed between the scattering plane and the plane in which the J/ψ meson decays. The production of J/ψ-mesons and ψ'-mesons has been investigated in muon scattering at concrete at the same incoming energy. The measured ratio of their cross sections agrees with the colour singlet model but disagrees with the simplified description which characterizes the 'photon-gluon fusion model'. The possible nuclear-mass dependence of the cross section for J/ψ-meson production has been investigated in interactions of muons with tin and carbon at an energy of 280 GeV. This possible dependence turns out to be absent which means that on the basis of the colour singlet model the distributions of the gluons in the nucleon are equal in tin and carbon. (author). 103 refs.; 60 figs.; 19 tabs

Isospin-dependent properties of asymmetric nuclear matter in relativistic mean field models

Science.gov (United States)

Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An

2007-11-01

Using various relativistic mean-field models, including nonlinear ones with meson field self-interactions, models with density-dependent meson-nucleon couplings, and point-coupling models without meson fields, we have studied the isospin-dependent bulk and single-particle properties of asymmetric nuclear matter. In particular, we have determined the density dependence of nuclear symmetry energy from these different relativistic mean-field models and compared the results with the constraints recently extracted from analyses of experimental data on isospin diffusion and isotopic scaling in intermediate energy heavy-ion collisions as well as from measured isotopic dependence of the giant monopole resonances in even-A Sn isotopes. Among the 23 parameter sets in the relativistic mean-field model that are commonly used for nuclear structure studies, only a few are found to give symmetry energies that are consistent with the empirical constraints. We have also studied the nuclear symmetry potential and the isospin splitting of the nucleon effective mass in isospin asymmetric nuclear matter. We find that both the momentum dependence of the nuclear symmetry potential at fixed baryon density and the isospin splitting of the nucleon effective mass in neutron-rich nuclear matter depend not only on the nuclear interactions but also on the definition of the nucleon optical potential.

All the states of the nucleon. Nucleon spectroscopy through the production of mesons; Le nucleon dans tous ses etats. Etude de la spectroscopie du nucleon via la photoproduction de mesons

Energy Technology Data Exchange (ETDEWEB)

Rebreyend, D

2006-10-15

The photoproduction of mesons on the nucleon gives a direct access to its spectroscopy and is a promising way for the study of the structure of the nucleon. The GRAAL experiment uses a tagged and polarized photon beam produced through the Compton diffusion of laser photons on the electrons circulating in the ESRF storage ring. The combination of this photon beam and an efficient detection system has allowed a series of measurements concerning the photoproduction of light mesons on the proton and on the neutron. The first 4 chapters are dedicated to the nucleon spectroscopy: the nucleon models and their consequences on the excited levels are recalled, the experimental technique used is described and the difficulties due to the extraction of relevant data are presented. Highly accurate measurements of cross-sections, {sigma} asymmetry beams and resonance parameters have been performed. The last part is dedicated to the principle of the measurement of the electric dipole momentum of the neutron. (A.C.)

Photoproduction of vector mesons off nucleons near threshold

International Nuclear Information System (INIS)

Friman, B.

1995-01-01

A simple meson-exchange model is proposed for the photoproduction of ρ- and ω-mesons off protons near threshold. This model provides a good description of the available data and implies a large ρ-nucleon interaction in the scalar channel (σ-exchange). This phenomenological interaction is applied to estimate the leading contribution to the self-energy of ρ-mesons in matter. The implications of our calculation for experimental studies of the ρ-meson mass in nuclei are discussed. (author)

Resonances in the S11 channel of the pion-nucleon scattering and the propagation of eta mesons in nuclear matter

International Nuclear Information System (INIS)

Sauermann, C.

1993-05-01

In the first part of the thesis the ηNN * coupling constant is determined. The model must contain both elastic πN scattering and ηproduction by excitation of the resonance and subsequent decay into an ηmeson and a nucleon. By fitting to the experimental data, which are present as real and imaginary part of the T matrix in the S 11 channel, the unknown coupling constants are determined. It is proved that unconditionally also the N * (1650) resonance must be regarded in order to reproduce the data well. The N * (1650) couples strongly to the pion and weakly to two pions, but scarcely to the ηmeson. The coupling to two pions is simulated in our model by introduction of an additional pseudoscalar meson of the mass 400 MeV. First a T matrix calculation is performed, in which the self-energy of the two resonances are regarded. In order to reach independence on the cutoffs subsequently the T matrix is calculated by means of the K matrix formalism. Finally an effective ηNN * coupling constant of 1.4 is found. In the second part of the thesis then with this coupling constant the behaviour of the ηmeson in nuclear matter at different densities is studied. (HSI)

Production and interaction of the η meson with nucleons and nuclei

Directory of Open Access Journals (Sweden)

Krzemień Wojciech

2016-01-01

Full Text Available We report on the status of the search for η-mesic nuclei and the studies of the interaction of the η meson with nucleons. Recently we have completed the analysis of the newWASA-at-COSY data on the production of the η meson with polarized proton beam. New results on the analyzing power for the p̄p → ppη reaction with more than an order of magnitude improved precision shed a new light on the production mechanism of the η meson in nucleon-nucleon collisions. Also, the latest results of the search for η-mesic nuclei are discussed.

δ meson effects in the Nolen-Schiffer anomaly

International Nuclear Information System (INIS)

Menezes, D.P.; Avancini, S.S.; Vasconcellos, C.Z.; Razeira, M.

2009-01-01

In this work we revisit the Okamoto-Nolen-Schiffer (ONS) anomaly in the context of four parametrizations of effective hadronic models, two of them with constant couplings between the nucleons and the mesons and two with density-dependent couplings. A Thomas-Fermi approximation is performed and the effects of the isovector-scalar virtual δ (a 0 (980)) mesons are investigated since they influence directly the proton and neutron effective masses in opposite ways. The ρ-ω mixing term is claimed to be important in the explanation of the ONS anomaly and is added in our calculations. We have concluded that as far as the ρ-ω mixing term is included, Δ M(Z, N) is clearly larger in models with δ than in models where this meson is not considered, which is not always the case if the coupling is discarded. None of the models is good enough to describe all experimental data, but the models that better describe the experimental values include the δ mesons. (orig.)

Photoproduction of vector mesons off nucleons near threshold

International Nuclear Information System (INIS)

Friman, B.; Soyeur, M.

1995-11-01

We propose a simple meson-exchange model of the photoproduction of ρ-and ω-mesons off protons near threshold (E γ < or∼2 GeV). We show that this model provides a good description of the available data and implies a large ρ-nucleon interaction in the scalar channel (σ-exchange). We use this phenomenological interaction to estimate the leading contribution to the self-energy of ρ-mesons in matter. We discuss the implications of our calculation for experimental studies of the ρ-meson mass in nuclei. (orig.)

Vector mesons in dense matter and dilepton production in heavy ion collisions at intermediate energies

Energy Technology Data Exchange (ETDEWEB)

Santini, Elvira

2008-02-15

The vector meson spectral functions are calculated to the first order in the nuclear matter density assuming the dominant contribution comes from the couplings of the vector mesons to nucleons and nucleon resonances. An attempt is made to reproduce the HADES dilepton production data with the in-medium spectral functions of the vector mesons using the Relativistic Quantum Molecular Dynamics (RQMD) transport model developed earlier for modelling heavy-ion collisions. The results are sensitive to the in-medium broadening of nucleon resonances. A generally good agreement with the HADES data is achieved for selfconsistent treatment of the nucleon resonance broadening and the vector meson spectral functions. (orig.)

Vector mesons in dense matter and dilepton production in heavy ion collisions at intermediate energies

International Nuclear Information System (INIS)

Santini, Elvira

2008-01-01

The vector meson spectral functions are calculated to the first order in the nuclear matter density assuming the dominant contribution comes from the couplings of the vector mesons to nucleons and nucleon resonances. An attempt is made to reproduce the HADES dilepton production data with the in-medium spectral functions of the vector mesons using the Relativistic Quantum Molecular Dynamics (RQMD) transport model developed earlier for modelling heavy-ion collisions. The results are sensitive to the in-medium broadening of nucleon resonances. A generally good agreement with the HADES data is achieved for selfconsistent treatment of the nucleon resonance broadening and the vector meson spectral functions. (orig.)

Chiral symmetry effect on the pion-nucleon coupling constant; O efeito da simetria quiral na constante de acoplamento pion-nucleon

Energy Technology Data Exchange (ETDEWEB)

Araujo, Vanilse da Silva

1997-12-31

In this work we study the effects of chiral symmetry in the pion-nucleon coupling constant in the context of the linear {sigma}- model. First, we introduce the linear {sigma}-model and we discuss the phenomenological hypothesis of CVC and PCAC. Next, we calculate the coupling constant g+{pi}{sub NN}(q{sup 2}) and the nucleon pionic mean square radius considering the contribution of all the diagrams up to one-loop in the framework of the linear {sigma}-model for different values of the mass of the sigma meson and we compare them with the phenomenological form factors. Finally we make an extension of the linear {sigma}-model that consists of taking into account the mass differences of ions and nucleons into the Lagrangian of the model, to study the change dependence of g{sub {pi}nn} (q{sup 2}) and of the mean square radius. (author) 21 refs., 17 figs., 4 tabs.

Compton scattering, meson exchange, and the polarizabilities of bound nucleons

International Nuclear Information System (INIS)

Feldman, G.; Mellendorf, K.E.; Eisenstein, R.A.; Federspiel, F.J.; Garino, G.; Igarashi, R.; Kolb, N.R.; Lucas, M.A.; MacGibbon, B.E.; Mize, W.K.; Nathan, A.M.; Pywell, R.E.; Wells, D.P.

1996-01-01

Elastic photon scattering cross sections on 16 O have been measured in the energy range 27 endash 108 MeV. These data are inconsistent with a conventional interpretation in which the electric and magnetic polarizabilities of the bound nucleon are unchanged from the free values and the meson-exchange seagull amplitude is taken in the zero-energy limit. Agreement with the data can be achieved by invoking either strongly modified polarizabilities or a substantial energy dependence to the meson-exchange seagull amplitude. It is argued that these seemingly different explanations are experimentally indistinguishable and probably physically equivalent. copyright 1996 The American Physical Society

Virtual meson cloud of the nucleon and intrinsic strangeness and charm

International Nuclear Information System (INIS)

Navarra, F.S.; Nielsen, M.; Duraes, F.O.; Barz, L.L.; Paiva, S.

1996-09-01

We have applied the Meson Cloud Model (MCM) to calculate the charm and strange antiquark distribution in the nucleon. The resulting distribution, in the case of charm, is very similar to the intrinsic charm momentum distribution in the nucleon. This seems to corroborate the hypothesis that the intrinsic charm is in the cloud and, at the same time, explains why other calculations with the MCM involving strange quark distributions fail in reproducing the low x region data. From the intrinsic strange distribution in the nucleon we have extracted the strangeness radius of the nucleon, which is in agreement with other meson cloud calculations. (author). 28 refs., 4 figs

Measurements of observables in the pion-nucleon system, nuclear a- dependence of heavy quark production and rare decays of D and B mesons

International Nuclear Information System (INIS)

Sadler, M.E.; Isenhower, L.D.

1992-01-01

This report discusses research on the following topics: pion-nucleon interactions; detector tomography facility; nuclear dependence of charm and beauty quark production and a study of two-prong decays of neutral D and B mesons; N* collaboration at CEBAF; and pilac experiments

Refitting density dependent relativistic model parameters including Center-of-Mass corrections

International Nuclear Information System (INIS)

Avancini, Sidney S.; Marinelli, Jose R.; Carlson, Brett Vern

2011-01-01

Full text: Relativistic mean field models have become a standard approach for precise nuclear structure calculations. After the seminal work of Serot and Walecka, which introduced a model Lagrangian density where the nucleons interact through the exchange of scalar and vector mesons, several models were obtained through its generalization, including other meson degrees of freedom, non-linear meson interactions, meson-meson interactions, etc. More recently density dependent coupling constants were incorporated into the Walecka-like models, which are then extensively used. In particular, for these models a connection with the density functional theory can be established. Due to the inherent difficulties presented by field theoretical models, only the mean field approximation is used for the solution of these models. In order to calculate finite nuclei properties in the mean field approximation, a reference set has to be fixed and therefore the translational symmetry is violated. It is well known that in such case spurious effects due to the center-of-mass (COM) motion are present, which are more pronounced for light nuclei. In a previous work we have proposed a technique based on the Pierls-Yoccoz projection operator applied to the mean-field relativistic solution, in order to project out spurious COM contributions. In this work we obtain a new fitting for the density dependent parameters of a density dependent hadronic model, taking into account the COM corrections. Our fitting is obtained taking into account the charge radii and binding energies for He 4 , O 16 , Ca 40 , Ca 48 , Ni 56 , Ni 68 , Sn 100 , Sn 132 and Pb 208 . We show that the nuclear observables calculated using our fit are of a quality comparable to others that can be found in the literature, with the advantage that now a translational invariant many-body wave function is at our disposal. (author)

Measuring the strangeness content of the nucleon by observing the ϕ-meson mass shift in nuclear matter

International Nuclear Information System (INIS)

Gubler, Philipp; Ohtani, Keisuke

2015-01-01

The modification of the ϕ-meson at finite density is studied by using QCD sum rules in combination with the maximum entropy method. As a result, it is found that the mass shift of the ϕ-meson is strongly correlated to the strangeness content of the nucleon, , which governs the depletion of the strange quark condensate in nuclear matter. (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.)

The kaon-nucleon interaction in the meson-exchange picture

International Nuclear Information System (INIS)

Buettgen, R.

1988-07-01

In this thesis we dealt with the free kaon-nucleon interaction which was constructed analogously to the Bonn potential in the meson-exchange picture. Identical vertices in the NN and KN interaction are parametrized by equal coupling constants and cut-off masses. Under the assumption of a SU(3) invariant interactions relations between the coupling constants have been determined so that also the experimentally only roughly known coupling constants to the strange vertices are fixed. The remaining free cut-off masses in the kaon vertices are fitted to the empirical scattering data. On the base of one-particle exchange processes the contribution of higher-order diagrams (box potentials with intermediate NK * , ΔK * , and ΔK states) in scattering phases, cross sections, and polarizations was studied. In the partial waves P 13 and D 03 the two-meson exchange processes lead to an essential improvement in the description of the empirical scattering phases. In the comparison of the calculated KN observables with the experimentally determined values (especially for the polarization in the elastic K + n channel) also the positive influence of the box potentials is shown. In the last part of the thesis for the similarly structured πN system it was studied whether here also the inclusion of uncorrelated two-meson exchange processes can remove the characteristical difficulties in the description of the empirical πN data. It results that the existing discrepancies between theoretical and empirical scattering phases can in this case not be removed by these higher-order processes. (orig./HSI) [de

A unified model of K- and π-mesons

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

On the foundation of an antecedent non-linear meson field theory it is suggested that the π-meson field may be described in terms of collective motions of the K-meson fields. A particular model of the K-nucleon interaction is considered whose collective π-modes have symmetrical PV coupling with the nucleon system; parity is conserved to a great extent for the π-nucleon system in the absence of strange particles. The direct K-nucleon interactions do not conserve parity; their sign and symmetry are qualitatively acceptable. The masses and coupling constants of the meson fields are determinate in terms of one universal coupling constant and a cut-off. The structure of this model suggests a natural way for the introduction of the 'spurion', describing weak interactions that violate strangeness. (author). 6 refs

Parity doubling structure of nucleon at non-zero density in the holographic mean field theory

Directory of Open Access Journals (Sweden)

He Bing-Ran

2014-06-01

Full Text Available We summarize our recent work in which we develope the holographic mean field approach to study the dense baryonic matter in a bottom-up holographic QCD model including baryons and scalar mesons in addition to vector mesons. We first show that, at zero density, the rate of the chiral invariant mass of nucleon is controlled by the ratio of the infrared boundary values of two baryon fields included in the model. Then, at non-zero density, we find that the chiral condensate decreases with the increasing density indicating the partial restoration of the chiral symmetry. Our result shows that the more amount of the proton mass comes from the chiral symmetry breaking, the faster the effective nucleon mass decrease with density.

D mesons in asymmetric nuclear matter

International Nuclear Information System (INIS)

Mishra, Amruta; Mazumdar, Arindam

2009-01-01

We calculate the in-medium D and D meson masses in isospin-asymmetric nuclear matter in an effective chiral model. The D and D mass modifications arising from their interactions with the nucleons and the scalar mesons in the effective hadronic model are seen to be appreciable at high densities and have a strong isospin dependence. These mass modifications can open the channels of the decay of the charmonium states (Ψ ' ,χ c ,J/Ψ) to DD pairs in dense hadronic matter. The isospin asymmetry in the doublet D=(D 0 ,D + ) is seen to be particularly appreciable at high densities and should show in observables such as their production and flow in asymmetric heavy-ion collisions in the compressed baryonic matter experiments in the future facility of FAIR, GSI. The results of the present work are compared to calculations of the D(D) in-medium masses in the literature using the QCD sum rule approach, quark meson coupling model, and coupled channel approach as well as to those from studies of quarkonium dissociation using heavy-quark potentials from lattice QCD at finite temperatures

Influence of the density dependence factor in effective nucleon-nucleon forces and interaction of 4He-particles with stable nuclei

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

Hot nuclear matter in the modified quark-meson coupling model with quark-quark correlations

International Nuclear Information System (INIS)

Zakout, I.; Jaqaman, H.R.

2000-01-01

Short-range quark-quark correlations in hot nuclear matter are examined within the modified quark-meson coupling (MQMC) model by adding repulsive scalar and vector quark-quark interactions. Without these correlations, the bag radius increases with the baryon density. However, when the correlations are introduced the bag size shrinks as the bags overlap. Also as the strength of the scalar quark-quark correlation is increased, the decrease of the effective nucleon mass M* N with the baryonic density is slowed down and tends to saturate at high densities. Within this model we study the phase transition from the baryon-meson phase to the quark-gluon plasma (QGP) phase with the latter modelled as an ideal gas of quarks and gluons inside a bag. Two models for the QGP bag parameter are considered. In one case, the bag is taken to be medium-independent and the phase transition from the hadron phase to QGP is found to occur at five to eight times ordinary nuclear matter density for temperatures less than 60 MeV. For lower densities, the transition takes place at a higher temperature, reaching up to 130 MeV at zero density. In the second case, the QGP bag parameter is considered to be medium-dependent as in the MQMC model for the hadronic phase. In this case, it is found that the phase transition occurs at much lower densities. (author)

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.)

The study of the cumulative effect in meson and nucleonic system production

International Nuclear Information System (INIS)

Pentia, M.

1984-01-01

Relativistic nuclear reactions with protons (deuterons) 8.0 GeV/c in the limiting fraamentation region (4-momentum transfer Q >= 1 GeV), with the particle production energy exceeding the nucleon-nucleon kinematical limit, were studied. The data acqusition, processing and analysis methods are presented along with experimental results like enerqy, angular distributions and A-mass dependence, carried out on DISC-2 Spectrometer (Dubna). Scale invariance character of the meson production, tells about local, pointlike interactions, interpreted like violent quark collisions. The quark structure functions of nuclei was obtained, proving the existence of multiquark states in nuclei. (author)

Microscopically-constrained Fock energy density functionals from chiral effective field theory. I. Two-nucleon interactions

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.

Study of the in-medium nucleon electromagnetic form factors using a light-front nucleon wave function combined with the quark-meson coupling model

Science.gov (United States)

de Araújo, W. R. B.; de Melo, J. P. B. C.; Tsushima, K.

2018-02-01

We study the nucleon electromagnetic (EM) form factors in symmetric nuclear matter as well as in vacuum within a light-front approach using the in-medium inputs calculated by the quark-meson coupling model. The same in-medium quark properties are used as those used for the study of in-medium pion properties. The zero of the proton EM form factor ratio in vacuum, the electric to magnetic form factor ratio μpGEp (Q2) /GMp (Q2) (Q2 = -q2 > 0 with q being the four-momentum transfer), is determined including the latest experimental data by implementing a hard constituent quark component in the nucleon wave function. A reasonable fit is achieved for the ratio μpGEp (Q2) /GMp (Q2) in vacuum, and we predict that the Q02 value to cross the zero of the ratio to be about 15 GeV2. In addition the double ratio data of the proton EM form factors in 4He and H nuclei, [GEp4He (Q2) /G4HeMp (Q2) ] / [GEp1H (Q2) /GMp1H (Q2) ], extracted by the polarized (e → ,e‧ p →) scattering experiment on 4He at JLab, are well described. We also predict that the Q02 value satisfying μpGEp (Q02) /GMp (Q0 2) = 0 in symmetric nuclear matter, shifts to a smaller value as increasing nuclear matter density, which reflects the facts that the faster falloff of GEp (Q2) as increasing Q2 and the increase of the proton mean-square charge radius. Furthermore, we calculate the neutron EM form factor double ratio in symmetric nuclear matter for 0.1 neutron double ratio is enhanced relative to that in vacuum, while for the proton it is quenched, and agrees with an existing theoretical prediction.

Five-meson VDM fits to the nucleon form factors

International Nuclear Information System (INIS)

Mehrotra, S.; Roos, M.

1975-01-01

Nucleon electromagnetic form factor data in the spacelike and the timelike regions are fitted with a VDM sum of (up to five) isovector and isoscalar pole terms. Finite width effects are included in the rho and the rhosup(,) terms. The effects of including the rhosup(,) and the psi(3105) are studied. Good fits are found only when the rhosup(,) is allowed to have a too low mass (1.2-1.4 GeV) and when in addition some of the couplings or other derived quantities disagree with other estimates. It is concluded that VDM is unable to describe the data unless one introduces a number of yet unknown mesons, such as ωsup(,), phisup(,), rhosup(,)(1.2), etc. (author)

Properties of rho and eta mesons in nuclear matter

International Nuclear Information System (INIS)

Herrmann, M.; Sauermann, C.; Friman, B.L.; Technische Hochschule Darmstadt; Noerenberg, W.; Technische Hochschule Darmstadt

1993-10-01

The properties of ρ- and η-mesons in nuclear matter are studied within the scope of hadronic models. Unknown model parameters are obtained from fits to scattering data. - The treatment of the ρ-meson includes the coupling to two pions which, in matter, are strongly mixed with delta-particle-nucleon-hole states. The ρ-meson self-energy is evaluated in a current conserving approximation with in-medium pion propagators and vertex corrections. While the position of the original peak in the spectral function remains almost unchanged, its width grows rapidly with increasing density. Consequently, the ρ-meson strength function is strongly dispersed at high densities. Due to vertex corrections a new peak at a mass around 3m π emerges with increasing density, while the spectral function around the two-pion threshold is found to be smooth at all densities. The η-meson is strongly mixed with N * (1535)-particle-nucleon-hole states in nuclear matter. The corresponding dispersion relations with an upper and a lower branch look similar to those of the (π, ΔN -1 )-modes. However, since the N * is an S-wave resonance in the ηN-channel, the repulsion of the two branches survives at zero momentum. (orig.)

Equation of state for isospin asymmetric matter of nucleons and deltas

International Nuclear Information System (INIS)

Lu Xiaohua; Zhang Yingxun; Li Zhuxia; Zhao Zhixiang

2008-01-01

An investigation on the equation of state of the isospin asymmetric, hot, dense matter of nucleons and deltas is performed based on the relativistic mean field theory. The QHD-II-type effective Lagrangian extending to the delta degree of freedom is adopted. Our results show that the equation of state is softened due to the inclusion of the delta degree of freedom. The baryon resonance isomer may occur depending on the delta-meson coupling. The results show that the densities for appearing the baryon resonance isomer, the densities for starting softening the equation of state and the extent of the softening depend not only on the temperature, the coupling strengths but also the isospin asymmetry of the baryon matter. (authors)

Multiplicity, momentum and angular characteristics of π- mesons for pC, dC, αC and CC interactions at 4.2 Gev/c per nucleon

International Nuclear Information System (INIS)

Agakishiev, N.N.; Akhababyan, N.; Armutlijsky, D.

1984-01-01

Multiplicity, momentum and angular characteristics of π - mesons produced in interactions of light nuclei (p, d, a, C) with carbon at a momentum of 4.2 GeV/c per nucleon are investigated. It is shown that the average multiplicity of π - mesons, , increases proportionally to the number of nucleons of the projectile nucleus which participate in the interaction with a carbon nucleus. A linear dependence of the dispersion of the π - meson multiplicity distribution on is observed. The shape of the π - meson distributions over Psub(lab.), THETAsub(lab.), Psub(tr) and ysub(lab.) weakly depends on the atomic weight of the projectile. The experimental data can be satisfactorily described by the Dubna version of the cascade model and by the multiple scattering model

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.)

Calculation of β-decay rates in a relativistic model with momentum-dependent self-energies

International Nuclear Information System (INIS)

Marketin, T.; Vretenar, D.; Ring, P.

2007-01-01

The relativistic proton-neutron quasiparticle random phase approximation (PN-RQRPA) is applied in the calculation of β-decay half-lives of neutron-rich nuclei in the Z≅28 and Z≅50 regions. The study is based on the relativistic Hartree-Bogoliubov calculation of nuclear ground states, using effective Lagrangians with density-dependent meson-nucleon couplings, and also extended by the inclusion of couplings between the isoscalar meson fields and the derivatives of the nucleon fields. This leads to a linear momentum dependence of the scalar and vector nucleon self-energies. The residual QRPA interaction in the particle-hole channel includes the π+ρ exchange plus a Landau-Migdal term. The finite-range Gogny interaction is employed in the T=1 pairing channel, and the model also includes a proton-neutron particle-particle interaction. The results are compared with available data, and it is shown that an extension of the standard relativistic mean-field framework to include momentum-dependent nucleon self-energies naturally leads to an enhancement of the effective (Landau) nucleon mass, and thus to an improved PN-QRPA description of β - -decay rates

A Dependence of Charmed Meson Production

Energy Technology Data Exchange (ETDEWEB)

Alves, Gilvan Augusto [Rio de Janeiro, CBPF

1992-03-01

One report is presented of a recent direct measurement of the nucleon number (A) dependence of the production cross sections for the charmed mesons $D^0$ and $D^+$ using $\\pi^+_{-}$ and $K^+_{-}$ beams incident on a segmented target of Be, Al, Cu and W. The data derive from the experiment E769 - Hadroproductlon of Charm at Fermilab. The experimental apparatus is described together with the following analysis. Starting from a sample of -1500 D mesons in the range of $O< x_{f} <1$, the data are found to be well described by the parameterization $\\sigma_{A}$ = $\\sigma_{O}$ , with $\\alpha = 0.99 \\pm 0.03$. The $x_f$ dependence of $\\alpha$ is examined and the results obtained are compared with those of other .experiments and wl th -theoretical expectations based on perturbatlve QCD and on an EMC like model of nuclear shadowing

Direct production of anti D0 mesons in neutrino-nucleon collisions

International Nuclear Information System (INIS)

Onipchuk, A.B.; Choban, E.A.

1992-01-01

The inclusive production of anti D 0 mesons in neutrino-nucleon collisions is studied from the viewpoint of the quasiparton mechanism. The ratio R anti D 0 υ = σ(υ μ N → μ - X)/σ(υ μ N → μ - X), the kinematic distributions averaged over the υ μ spectrum, and the average kinematic characteristics of the final μ - and anti D 0 mesons are calculated. The number of events with anti D 0 -meson production is estimated as a function of the number of inclusive events

Covariant computation of e+e- production in nucleon-nucleon collisions

International Nuclear Information System (INIS)

Haglin, K.; Kapusta, J.; Gale, C.

1989-01-01

Electron-positron production differential cross sections in nucleon-nucleon collisions are calculated analytically via meson exchange with a realistic pseudovector coupling including strong interaction form factors. These results are compared with newly obtained data from the DLS at the BEVALAC of proton on beryllium. A comparison with the soft photon approximation is also made. (orig.)

Relativistic one-boson-exchange model for the nucleon-nucleon interaction

International Nuclear Information System (INIS)

Gross, F.; Van Orden, J.W.; Holinde, K.

1992-01-01

Nucleon-nucleon data below 300-MeV laboratory energy are described by a manifestly covariant wave equation in which one of the intermediate nucleons is restricted to its mass shell. Antisymmetrization of the kernel yields an equation in which the two nucleons are treated in an exactly symmetric manner, and in which all amplitudes satisfy the Pauli principle exactly. The kernel is modeled by the sum of one boson exchanges, and four models, all of which fit the data very well (χ 2 congruent 3 per data point) are discussed. Two models require the exchange of only the π, σ, ρ, and ω, but also require an admixture of γ 5 coupling for the pion, while two other models restrict the pion coupling to pure γ 5 γ μ , but require the exchange of six mesons, including the η, and a light scalar-isovector meson referred to as σ 1 . Deuteron wave functions resulting from these models are obtained. The singularities and relativistic effects which are a part of this approach are discussed, and a complete development of the theory is presented

A-dependence for the charmed meson production

International Nuclear Information System (INIS)

Alves, Gilvan Augusto.

1992-03-01

A report is presented of a recent direct measurement of the nucleon number (λ) dependence of the production cross sections for the charmed mesons D 0 and D + using π +- beams incident on a segmented target of Be, Al, Cu and W. The data derive from the experiment E769 - Hadroproduction of Charm - at Fermilab. The experimental apparatus is described together with the following analysis. Starting from a sample of ∼ 1500 D mesons in the range of O F A = σ O A α , with α = 0.99 ± 0.03. The X F dependence of α is examined and the results obtained are compared with those of other experiments and with theoretical expectations based on perturbative QCD and on an EMC like model of nuclear shadowing. (author). 85 refs, 61 figs, 22 tabs

Electromagnetic Meson Production in the Nucleon Resonance Region

Energy Technology Data Exchange (ETDEWEB)

Volker Burkert; T.-S. H. Lee

2004-10-01

Recent experimental and theoretical advances in investigating electromagnetic meson production reactions in the nucleon resonance region are reviewed. The article gives a description of current experimental facilities with electron and photon beams and presents a unified derivation of most of the phenomenological approaches being used to extract the resonance parameters from the data. The analyses of {pi} and {eta} production data and the resulting transition form factors for the {Delta}(1232)P{sub 33}, N(1535)S{sub 11}, N(1440)P{sub 11}, and N(1520)D{sub 13} resonances are discussed in detail. The status of our understanding of the reactions with production of two pions, kaons, and vector mesons is also reviewed.

Meson dynamics and the nuclear many-body problem. II. Finite density Hartree-Fock

International Nuclear Information System (INIS)

Wilets, L.; Puff, R.D.; Chiang, D.; Nutt, W.T.

1976-01-01

The field-theoretic many-nucleon problem is formulated, and an analysis which sums all ''uncrossed meson line'' diagrams is investigated in detail. The calculation of energy per nucleon, after proper identification of infinite mass renormalization terms, exhibits effects of nuclear recoil, relativistic kinematics, and retardation. Numerical results are presented for π and ω mesons, and the nucleon interaction energies obtained are compared with the traditional static limit of infinite nucleon mass

The isospin dependent nucleon–nucleon inelastic cross section in the nuclear medium

Directory of Open Access Journals (Sweden)

Qingfeng Li

2017-10-01

Full Text Available The calculation of the energy-, density-, and isospin-dependent Δ production cross sections in nucleon–nucleon (NN scattering σNN→NΔ⁎ has been performed within the framework of the relativistic BUU approach. The NΔ cross sections are calculated in Born approximation taking into account the effective mass splitting of the nucleons and Δs in asymmetric matter. Due to the different mass splitting for neutron, proton and differently charged Δs, it is shown that, similar to the NN elastic ones, the reductions of NΔ inelastic cross sections in isospin-asymmetric nuclear medium are different from each other for all the individual channels and the effect is largest and of opposite sign for the Δ++ and Δ− states. This approach is also compared to calculations without effective mass splitting and with splitting derived from Dirac–Brueckerner (DB calculations. The isospin dependence of the NΔ cross sections is expected to influence the production of π+ and π− mesons as well as their yield ratio, and thus affect the use of the latter quantity as a probe of the stiffness of the symmetry energy at supranormal densities.

Nucleons, mesons and quarks: the electron scattering approach

International Nuclear Information System (INIS)

Frois, B.

1985-05-01

A few examples of the research carried out by electron scattering in order to elucidate the relevant degrees of freedom for nuclear physics. Is considered first quasielastic scattering from 3 He which gives some insight into the properties of the nucleon in the nuclear medium. Then examples of meson exchange currents are presented. Finally, the present status of our understanding of shorter range effects is discussed

ρ, ω, and φ meson-nucleon scattering lengths from QCD sum rules

International Nuclear Information System (INIS)

Koike, Y.

1995-01-01

The QCD sum rule method is applied to derive a formula for the ρ, ω, and φ meson-nucleon spin-isospin--averaged scattering lengths a ρ,ω,φ . We found that the crucial matrix elements are left-angle bar qγ μ D ν q right-angle N (q=ud) (twist-2 nucleon matrix element) for a ρ,ω and m s left-angle bar ss right-angle N for a φ , and obtained a ρ =0.14±0.07 fm, a ω =0.11±0.06 fm, and a φ =0.035±0.020 fm. These small numbers originate from a common factor 1/(m N +m ρ,ω,φ ). Our result suggests a slight increase (<60 MeV for ρ and ω, and <15 MeV for φ) of the effective mass of these vector mesons in nuclear matter (in the dilute nucleon-gas approximation). The origin of the discrepancy with Hatsuda-Lee was clarified

The quark model and the force between nucleons

International Nuclear Information System (INIS)

Faessler, A.

1985-01-01

The resonating group method is used to calculate in the six quark model the /sup 3/S and /sup 1/S phase shifts of the nucleon-nucleon interaction. For large distances the model is supplemented byπ, σ, rho and ω- meson exchange. The role of the orbital [42]/sub r/ symmetry for the short range repulsion is studied. It is shown that at short distances the orbital [42]/sub r/ symmetry plays an important role which is even enlarged by the colour magnetic interaction. The [42]/sub r/ symmetry enforces the short range repulsion by a node which it requests at short distances. The mechanism is complicated by the fact, that the orbital [6]/sub r/ symmetry ia admixed by about the same weight. The authors show that for meson exchanges which mediate the long range behaviour they can now use the SU/sub 3/ flavour ratios of the meson-nucleon coupling constants even for the ω-nucleon coupling. For the ω-meson one had to use in the OBEP's a ω-N coupling constant twice to three times as large as predicted by SU/sub 3/ flavour to describe the short range repulsion. They also comment on the different contributions to this conference about the quark-model and the NN interaction

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

Spin-dependent parton distributions in the nucleon

Energy Technology Data Exchange (ETDEWEB)

Cloet, I.C. [Special Research Centre for the Subatomic Structure of Matter and Department of Physics and Mathematical Physics, University of Adelaide, SA 5005 (Australia); Bentz, W. [Department of Physics, School of Science, Tokai University Hiratsuka-shi, Kanagawa 259-1292 (Japan); Thomas, A.W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

2005-04-15

Spin-dependent quark light-cone momentum distributions are calculated for a nucleon in the nuclear medium. We utilize a modified NJL model where the nucleon is described as a composite quark-diquark state. Scalar and vector mean fields are incorporated in the nuclear medium and these fields couple to the confined quarks in the nucleon. The effect of these fields on the spin-dependent distributions and consequently the axial charges is investigated. Our results for the 'spin-dependent EMC effect' are also discussed.

An upgraded version of the nucleon meson transport code: NMTC/JAERI97

Energy Technology Data Exchange (ETDEWEB)

Takada, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yoshizawa, Nobuaki; Kosako, Kazuaki; Ishibashi, Kenji

1998-02-01

The nucleon-meson transport code NMTC/JAERI is upgraded to NMTC/JAERI97 which has new features not only in physics model and nuclear data but also in computational procedure. NMTC/JAERI97 implements the following two new physics models: an intranuclear cascade model taking account of the in-medium nuclear effects and the preequilibrium calculation model based on the exciton one. For treating the nucleon transport process more accurately, 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. Other than those physical aspects, a new geometry package based on the Combinatorial Geometry with multi-array system and the importance sampling technique are 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 resultant NMTC/JAERI97 is tuned to be executed on the UNIX system. This paper explains about the function, physics models and geometry model adopted in NMTC/JAERI97 and guides how to use the code. (author)

Temperature dependent relativistic microscopic optical potential and mean free paths of nucleons

International Nuclear Information System (INIS)

Han Yinlu; Shen Qingbiao; Zhuo Yizhong

1993-01-01

The relativistic microscopic optical potential, mean free paths and Schroedinger equivalent potential of nucleons at finite temperature in nuclear matter are studied based on Walecka's model and thermo field dynamics. We let only the Hartree-Fock self-energy of nucleon represent to be the real part of the microscopic optical potential and the fourth order of meson exchange diagrams, i.e. the core polarization represent the imaginary part of microscopic optical potential in nuclear matter. The microscopic optical potential of finite nuclei is obtained with the local density approximation

Meson-exchange N-N potential

International Nuclear Information System (INIS)

Nutt, W.T.

1976-01-01

A meson-theoretic model of the intermediate range nucleon-nucleon potential is presented with emphasis placed on the two-pion exchange contribution. The Bethe-Salpeter equation is reduced, by the Blankenbecler-Sugar technique, to a Lippmann-Schwinger equation, from which an approximate nonlocal, energy-dependent potential is obtained. The nucleon-antinucleon pair contribution, which plagues meson-theoretical two-pion calculations, is suppressed by the complex poles of the one-nucleon Green's function. The importance of the retention of the explicit energy dependence of the potential is demonstrated by calculating the off-shell scattering matrices. The potential is presented in a linearized (in energy) form with the core region adjusted to produce a fit to low energy data

Mesonic and Quark Degrees of Freedom in the Neutron Star Matter

International Nuclear Information System (INIS)

Kubis, S.; Kutschera, M.; Niemiec, J.; Stachniewicz, S.

1999-01-01

Full text: It is expected that mesonic and quark degrees of freedom may play an important role in the physics of dense matter in neutron stars. Any conclusions, however, as to the presence of e.g. meson condensates and/or quark matter inside neutron stars are subject to uncertainties which reflect incompatible model predictions at a purely nucleon level. In our project, as far as mesonic contributions to the equation of state of dense matter are concerned, we focus on the role of kaons and the isovector scalar meson a 0 (980). We find that a threshold density for the kaon condensate to form is very sensitive to a high density behaviour of the electron chemical potential, which is not well known due to uncertainties of nucleon-nucleon interactions. An important effect of the inclusion of the a 0 meson is a splitting of proton and neutron masses in the neutron star matter. A proper construction of the nucleon-quark phase transition in dense neutron star matter predicts that nucleons and quarks coexist over a finite range of pressure, with quarks (nucleons) filling gradually larger (smaller) fraction of space. We find, using a simple bag-model equation of state for the quark matter, that properties of such a mixed quark-nucleon phase are determined by the behaviour of nucleon matter isobars which is sensitive to the nuclear symmetry energy at high densities. We study also implications of the presence of a mixed phase for the structure of neutron stars. (author)

A-dependence of inclusive πsup(+-) meson photoproduction

International Nuclear Information System (INIS)

Alanakyan, K.V.; Amaryan, M.D.; Demirchyan, R.A.; Egiyan, K.Sh.; Kocharova, Zh.L.; Ogandjanyan, M.S.; Sharabyan, Yu.G.; Stepanyan, S.G.

1981-01-01

The experimental data on A-dependence of photopions in wide energy and angular intervals of secondary PI +- -mesons are discussed. It is shown that if the invariant cross section of photopion production on 12 C, 27 Al, 63 Cu, 118 Sn and 208 Pb nuclei in the γ+A→PI +- +X reaction is represented in the form of f approximately equal to BAsup(n), then in the energy dependence of exponent n one can observe the same singularities as in the analogous hadron processes. The expansion of the angular interval up to 20-160 deg in the laboratory system made it possible to study in detail the nature of these singularities. The attempts are made to explain the observed singularities in the energy dependence n=n(TPI) by taking into account additional (to tne direct process of photoproduction on nuclear nucleons) sources of the inclusive PI-meson production [ru

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)

Production of $D^{\\pm}$ Mesons in $K^+$ Nucleon Collisions at 250 GeV

Energy Technology Data Exchange (ETDEWEB)

da Motta Filho, Helio [Rio de Janeiro, CBPF

1993-11-01

The $X_f$, $P^2_t$ and $p_t$ distribution of $D^{\\pm}$ mesons produced by 250 GeV $K^+$-nucleon interactions are measured through the decay channel $D^{\\pm} \\to K^{\\mp}\\pi^{\\pm} \\pi^{\\pm}$....

A relativistic, meson exchange model of pion-nucleon scattering

International Nuclear Information System (INIS)

Pearces, B.C.; Jennings, B.K.

1990-06-01

A relativistic meson exchange approach to the pion-nucleon interaction is developed using a three-dimensional relativistic two-body propagator, and the results using different propagators are compared. The relativistic approach is able to describe low energy scattering up to 400 MeV above threshold, while preserving the soft pion theorems. The different propagators give similar results, as the form factors necessary to get a fit suppress much of the multiple scattering. (Author) (24 refs., 4 tabs., 6 figs.)

Pseudoscalar Meson Electroproduction and Transversity

International Nuclear Information System (INIS)

Goldstein, G.; Liuti, S.

2011-01-01

Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged boson limit can be described by generalized parton distributions (GPDs). Including spin dependence in the description requires 8 independent quark-parton and gluon-parton functions. The chiral even subset of 4 quark-nucleon GPDs are related to nucleon form factors and to parton distribution functions. The chiral odd set of 4 quark-nucleon GPDs are related to transversity, the tensor charge, and other quantities related to transversity. Different meson or photon production processes access different combinations of GPDs. This is analyzed in terms of t-channel exchange quantum numbers, J PC and it is shown that pseudoscalar production can isolate chiral odd GPDs. There is a sensitive dependence in various cross sections and asymmetries on the tensor charge of the nucleon and other transversity parameters. In a second section, analyticity and completeness are shown to limit the partonic interpret ation of the GPDs in the ERBL region.

Mesons and quarks in nuclei

International Nuclear Information System (INIS)

Oset, E.

1980-01-01

A short review of the topic of mesons in nuclei is exposed paying particular attention to the relationship between several mesonic processes. Special emphasis is put into the microscopic pictures that can ultimately relate all these processes with the elementary coupling of mesons to the nuclear hadronic components. The importance of the short range part of the nuclear interaction opens the doors to a more basic understanding in terms of the quark components of nucleons and isobars. (orig.)

Studies of nucleon resonance structure in exclusive meson electroproduction

International Nuclear Information System (INIS)

Aznauryan, I.G.; Bashir, A.; Braun, V.M.

2013-01-01

Studies of the structure of excited baryons are key factors to the N* program at Jefferson Lab (JLab). Within the first year of data taking with the Hall B CLAS12 detector following the 12 GeV upgrade, a dedicated experiment will aim to extract the N* electrocouplings at high photon virtualities Q 2 . This experiment will allow exploration of the structure of N* resonances at the highest photon virtualities ever achieved, with a kinematic reach up to Q 2 = 12 GeV 2 . This high-Q 2 reach will make it possible to probe the excited nucleon structures at distance scales ranging from where effective degrees of freedom, such as constituent quarks, are dominant through the transition to where nearly massless bare-quark degrees of freedom are relevant. In this document, we present a detailed description of the physics that can be addressed through N* structure studies in exclusive meson electroproduction. The discussion includes recent advances in reaction theory for extracting N* electrocouplings from meson electroproduction off protons, along with Quantum Chromodynamics (QCD)-based approaches to the theoretical interpretation of these fundamental quantities. This program will afford access to the dynamics of the nonperturbative strong interaction responsible for resonance formation, and will be crucial in understanding the nature of confinement and dynamical chiral symmetry breaking in baryons, and how excited nucleons emerge from QCD. (author)

Production of φ-mesons in N-barN annihilation and polarized strangeness in the nucleon

International Nuclear Information System (INIS)

Sapozhnikov, M.G.

1995-01-01

Recent results from the experiments on φ-meson production in annihilation of stopped antiprotons have demonstrated significant (by a factor of 30-50) violation of the OZI rule. Experimental information on φ-meson production is discussed and possible theoretical explanations of the strong OZI rule violation as a manifestation of polarized intrinsic nucleon strangeness are reviewed. 70 refs., 6 figs., 2 tabs

Mesonic effects in nuclear physics

International Nuclear Information System (INIS)

Johnson, M.

1978-01-01

The relation between mesons and nucleons and the properties of nuclear matter, as presently understood, is considered in these lectures. Feynman diagrams, meson theoretical nucleon-nucleon interactions, mesonic components in nuclear wave functions, direct observation of mesonic components in NN scattering above the pion production threshold, nuclear matter theory, and pion condensation are treated. 120 references

Temperature, chemical potential and the ρ meson

International Nuclear Information System (INIS)

Roberts, C. D.; Schmidt, S. M.

2000-01-01

Models of QCD must confront nonperturbative phenomena such as confinement, dynamical chiral symmetry breaking (DCSB) and the formation of bound states. In addition, a unified approach should describe the deconfinement and chiral symmetry restoring phase transition exhibited by strongly-interacting matter under extreme conditions of temperature and density. Nonperturbative Dyson-Schwinger equation (DSE) models provide insight into a wide range of zero temperature hadronic phenomena; e.g., non-hadronic electroweak interactions of light- and heavy-mesons, and diverse meson-meson and meson-nucleon form factors. This is the foundation for their application at nonzero-(T, μ). Herein the authors describe the calculation of the reconfinement and chiral symmetry restoring phase boundary, and the medium dependence of ρ-meson properties. They also introduce an extension to describe the time-evolution in the plasma of the quark's scalar and vector self energies based on a Vlasov equation

Time dependence of the field energy densities surrounding sources: Application to scalar mesons near point sources and to electromagnetic fields near molecules

International Nuclear Information System (INIS)

Persico, F.; Power, E.A.

1987-01-01

The time dependence of the dressing-undressing process, i.e., the acquiring or losing by a source of a boson field intensity and hence of a field energy density in its neighborhood, is considered by examining some simple soluble models. First, the loss of the virtual field is followed in time when a point source is suddenly decoupled from a neutral scalar meson field. Second, an initially bare point source acquires a virtual meson cloud as the coupling is switched on. The third example is that of an initially bare molecule interacting with the vacuum of the electromagnetic field to acquire a virtual photon cloud. In all three cases the dressing-undressing is shown to take place within an expanding sphere of radius r = ct centered at the source. At each point in space the energy density tends, for large times, to that of the ground state of the total system. Differences in the time dependence of the dressing between the massive scalar field and the massless electromagnetic field are discussed. The results are also briefly discussed in the light of Feinberg's ideas on the nature of half-dressed states in quantum field theory

A-dependence for the charmed meson production; Dependencia em A para a producao de mesons charmosos

Energy Technology Data Exchange (ETDEWEB)

Alves, Gilvan Augusto

1992-03-01

A report is presented of a recent direct measurement of the nucleon number ({lambda}) dependence of the production cross sections for the charmed mesons D{sup 0} and D{sup +} using {pi}{sup +-} beams incident on a segmented target of Be, Al, Cu and W. The data derive from the experiment E769 - Hadroproduction of Charm - at Fermilab. The experimental apparatus is described together with the following analysis. Starting from a sample of {approx} 1500 D mesons in the range of O < X{sub F} < 1, the data are found to be well described by the parameterization {sigma}{sub A} = {sigma}{sub O} A{sup {alpha}}, with {alpha} = 0.99 {+-} 0.03. The X{sub F} dependence of {alpha} is examined and the results obtained are compared with those of other experiments and with theoretical expectations based on perturbative QCD and on an EMC like model of nuclear shadowing. (author). 85 refs, 61 figs, 22 tabs.

Relativistic mean field theory with density dependent coupling constants for nuclear matter and finite nuclei with large charge asymmetry

Energy Technology Data Exchange (ETDEWEB)

Typel, S; Wolter, H H [Sektion Physik, Univ. Muenchen, Garching (Germany)

1998-06-01

Nuclear matter and ground state properties for (proton and neutron) semi-closed shell nuclei are described in relativistic mean field theory with coupling constants which depend on the vector density. The parametrization of the density dependence for {sigma}-, {omega}- and {rho}-mesons is obtained by fitting to properties of nuclear matter and some finite nuclei. The equation of state for symmetric and asymmetric nuclear matter is discussed. Finite nuclei are described in Hartree approximation, including a charge and an improved center-of-mass correction. Pairing is considered in the BCS approximation. Special attention is directed to the predictions for properties at the neutron and proton driplines, e.g. for separation energies, spin-orbit splittings and density distributions. (orig.)

Mesonic and isobar degrees of freedom in nuclei

International Nuclear Information System (INIS)

Muether, H.

1978-01-01

A study is made in 16 O of the effects of mesonic and isobar degrees of freedom. Taking these degrees of freedom explicitly into account causes a change of the bare nucleon-nucleon (NN) interaction going from the description of the two-nucleon system (NN-scattering, deuteron) to the many-body system of complex nuclei. Three main effects are discussed: First, the mesonic degrees of freedom, taken into account in a noncovariant perturbation theory, introduce and additional density dependence into the NN interaction. In a Brueckner-Hartree-Fock calculation for 16 O this leads to an improvement of the radius with a small change of the energy. Second, fourth-order iterative diagrams involving NΔ-and ΔΔ-intermediate states give less medium range attraction in complex nuclei than a NN-potential which is also fitted to the NN-data but does not treat these terms explicitly. Third, effective three-N forces, caused by excitation of isobars, give rise to a small amount of attraction only. For 16 O the additional binding energy is only about 0.5 MeV per particle. (author)

Strange mesonic transition form factor

International Nuclear Information System (INIS)

Goity, J.L.; Musolf, M.J.

1996-01-01

The strange-quark vector current ρ-to-π meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a φ-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by φ-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cutoff mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciable in moderate-parallel Q 2 parallel parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon. copyright 1996 The American Physical Society

Quantum field model of strong-coupling binucleon

International Nuclear Information System (INIS)

Amirkhanov, I.V.; Puzynin, I.V.; Puzynina, T.P.; Strizh, T.A.; Zemlyanaya, E.V.; Lakhno, V.D.

1996-01-01

The quantum field binucleon model for the case of the nucleon spot interaction with the scalar and pseudoscalar meson fields is considered. It is shown that the nonrelativistic problem of the two nucleon interaction reduces to the one-particle problem. For the strong coupling limit the nonlinear equations describing two nucleons in the meson field are developed [ru

Effect of nucleon and hadron structure changes in-medium and its impact on observables

Energy Technology Data Exchange (ETDEWEB)

K. Saito; K. Tsushima; A.W. Thomas

2005-07-05

We study the effect of hadron structure changes in a nuclear medium using the quark-meson coupling (QMC) model. The QMC model is based on a mean field description of non-overlapping nucleon (or baryon) bags bound by the self-consistent exchange of scalar and vector mesons in the isoscalar and isovector channels. The model is extended to investigate the properties of finite nuclei, in which, using the Born-Oppenheimer approximation to describe the interacting quark-meson system, one can derive the effective equation of motion for the nucleon (or baryon), as well as the self-consistent equations for the meson mean fields.

The nucleon-nucleon interaction from a realistic pseudoscalar-vector chiral lagrangian

International Nuclear Information System (INIS)

Kaiser, N.; Meissner, U.G.; Massachusetts Inst. of Tech., Cambridge

1990-01-01

We investigate the static nucleon-nucleon potential in the framework of a non-linear chiral meson theory. The model includes pions as well as the vector mesons ρ and ω. All parameters are fixed in the meson sector and predictions about the nucleon-nucleon interaction follow without adjusting any parameters. We use an S-matrix approach to calculate correlated two-pion exchange between two solitons. The most prominent feature of this two-pion exchange is that it leads very natural to attraction in the scalar-isoscalar channel. We also discuss the effect of πp correlations on the central potential, and present the spectral function related to the correlated two-pion exchange. Furthermore, we study the form factors of the nucleon sources related to the two-pion exchange and find that they are of dipole type with typical cutoff scales Λ D ≅ 700 MeV. We also discuss the destructive interference of π- and ρ-exchange in the isovector tensor potential. Altogether, we present a unified treatment of meson exchange phenomenology based on a serious model of the nucleon. Finally, we point out the limitations of the model and discuss some further applications. (orig.)

Nucleon-nucleon interaction of a chiral σ-ω model at finite temperature

International Nuclear Information System (INIS)

Rukeng Su

1994-01-01

By using the imaginery time Green's function method, the nucleon-nucleon interaction of the chiral σ-ω model has been investigated under the one-loop approximation. The effective masses of the pion, σ-meson and ω-meson at finite temperature are given. We have found that the potential well of the nucleon-nucleon interaction becomes shallow as the temperature increases. At a critical temperature T c (70 MEV) the potential well disappears. (author)

Quarks and mesons in nuclei

International Nuclear Information System (INIS)

Rho, M.

1981-01-01

Quantum chromodynamics is believed to be candidate theory for the strong interactions and contains as its ingredients spinor quark fields and vector gluons, none of which can perhaps be ever liberated and detected in laboratories. A nucleus consists of nucleons bound by nuclear force which are however separately observable and which seem to preserve their identities even under extreme conditions. An intriguing question is: when compressed to high densities or heated to high temperature, at what point does a nuclear matter cease to be describable in terms of nucleon and meson degrees of freedom, but become a plasma of quarks and gluons; and how does this transition occur. This is not an idle question. If quarks and gluons are never to be observed isolated, then it may be that at low energies (or at low densities) they are not the right variables to do physics with. Instead hadrons must be. On the other hand, asymptotic freedom - the unique property of non-abelian gauge theories to which QCD belongs that quark-gluon and gluon-gluon interactions get weaker at short distances - tells us that at some large matter density the matter must necessarily be in the form of quark gas interacting only weakly. This means that a change in degrees of freedom must take place. We would like to know where this occurs and how. In this talk, I would like to address to this question by discussing first the large success we have had in understanding the role that mesons play in finite nuclei and nuclear matter and then attempting to correlate nucleon and meson degrees of freedom to quark-gluon degrees of freedom. In my opinion we are now at a stage where we feel fairly confident in our understanding of nucleon-meson structure of nuclei and nuclear matter and any further progress in deeper understanding of nuclear dynamics - and strong interactions - must come from QCD or its effective version, bags or strings. (orig.)

Two-body Dirac equations for nucleon-nucleon scattering

International Nuclear Information System (INIS)

Liu Bin; Crater, Horace

2003-01-01

We investigate the nucleon-nucleon interaction by using the meson exchange model and the two-body Dirac equations of constraint dynamics. This approach to the two-body problem has been successfully tested for QED and QCD relativistic bound states. An important question we wish to address is whether or not the two-body nucleon-nucleon scattering problem can be reasonably described in this approach as well. This test involves a number of related problems. First we must reduce our two-body Dirac equations exactly to a Schroedinger-like equation in such a way that allows us to use techniques to solve them already developed for Schroedinger-like systems in nonrelativistic quantum mechanics. Related to this, we present a new derivation of Calogero's variable phase shift differential equation for coupled Schroedinger-like equations. Then we determine if the use of nine meson exchanges in our equations gives a reasonable fit to the experimental scattering phase shifts for n-p scattering. The data involve seven angular momentum states including the singlet states 1 S 0 , 1 P 1 , 1 D 2 and the triplet states 3 P 0 , 3 P 1 , 3 S 1 , 3 D 1 . Two models that we have tested give us a fairly good fit. The parameters obtained by fitting the n-p experimental scattering phase shift give a fairly good prediction for most of the p-p experimental scattering phase shifts examined (for the singlet states 1 S 0 , 1 D 2 and triplet states 3 P 0 , 3 P 1 ). Thus the two-body Dirac equations of constraint dynamics present us with a fit that encourages the exploration of a more realistic model. We outline generalizations of the meson exchange model for invariant potentials that may possibly improve the fit

Density dependent effective interactions

International Nuclear Information System (INIS)

Dortmans, P.J.; Amos, K.

1994-01-01

An effective nucleon-nucleon interaction is defined by an optimal fit to select on-and half-off-of-the-energy shell t-and g-matrices determined by solutions of the Lippmann-Schwinger and Brueckner-Bethe-Goldstone equations with the Paris nucleon-nucleon interaction as input. As such, it is seen to better reproduce the interaction on which it is based than other commonly used density dependent effective interactions. The new (medium modified) effective interaction when folded with appropriate density matrices, has been used to define proton- 12 C and proton- 16 O optical potentials. With them elastic scattering data are well fit and the medium effects identifiable. 23 refs., 8 figs

Massive neutron star with strangeness in a relativistic mean-field model with a high-density cutoff

Science.gov (United States)

Zhang, Ying; Hu, Jinniu; Liu, Peng

2018-01-01

The properties of neutron stars with the strangeness degree of freedom are studied in the relativistic mean-field (RMF) model via including a logarithmic interaction as a function of the scalar meson field. This interaction, named the σ -cut potential, can largely reduce the attractive contributions of the scalar meson field at high density without any influence on the properties of nuclear structure around the normal saturation density. In this work, the TM1 parameter set is chosen as the RMF interaction, while the strengths of σ -cut potential are constrained by the properties of finite nuclei so that we can obtain a reasonable effective nucleon-nucleon interaction. The hyperons Λ ,Σ , and Ξ are considered in neutron stars within this framework, whose coupling constants with mesons are determined by the latest hyperon-nucleon and Λ -Λ potentials extracted from the available experimental data of hypernuclei. The maximum mass of neutron star can be larger than 2 M⊙ with these hyperons in the present framework. Furthermore, the nucleon mass at high density will be saturated due to this additional σ -cut potential, which is consistent with the conclusions obtained by other calculations such as Brueckner-Hartree-Fock theory and quark mean-field model.

Energy and system size dependence of phi meson production in Cu+Cu and Au+Au collisions

Energy Technology Data Exchange (ETDEWEB)

STAR Coll

2008-10-28

We study the beam-energy and system-size dependence of {phi} meson production (using the hadronic decay mode {phi} {yields} K{sup +}K{sup -}) by comparing the new results from Cu + Cu collisions and previously reported Au + Au collisions at {radical}s{sub NN} = 62.4 and 200 GeV measured in the STAR experiment at RHIC. Data presented are from midrapidity (|y| < 0.5) for 0.4 < p{sub T} < 5 GeV/c. At a given beam energy, the transverse momentum distributions for {phi} mesons are observed to be similar in yield and shape for Cu + Cu and Au + Au colliding systems with similar average numbers of participating nucleons. The {phi} meson yields in nucleus-nucleus collisions, normalized by the average number of participating nucleons, are found to be enhanced relative to those from p + p collisions with a different trend compared to strange baryons. The enhancement for {phi} mesons is observed to be higher at {radical}s{sub NN} = 200 GeV compared to 62.4 GeV. These observations for the produced {phi}(s{bar s}) mesons clearly suggest that, at these collision energies, the source of enhancement of strange hadrons is related to the formation of a dense partonic medium in high energy nucleus-nucleus collisions and cannot be alone due to canonical suppression of their production in smaller systems.

The nucleon-nucleon interaction in the presence of the electromagnetic field: Nucleon-nucleon bremsstrahlung

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

Properties of the ρ meson in dense nuclear matter

International Nuclear Information System (INIS)

Herrmann, M.

1992-05-01

In order to reach a description of the ρ meson, which is in accordance with the principles of the gauge invariance of the electromagnetic interaction, the vector-dominance hypothesis, and the unitarity a model for the ρ meson in the vacuum is developed. Thereafter follows the calculation of the properties of the ρ meson in nuclear matter. First the connection between the spectral function of the ρ meson and the dilepton production rate for an equilibrium state is derived. Then the model for the pion in nuclear matter is described. Following approximations are applied: The description of the pion-baryon interaction pursues non-relativistically and both the width of the delta resonance and the short-range repulsive delta-nucleon interaction is neglected. The self-energy of the ρ meson in nuclear matter following from this description is formally derived from the requirement to couple the ρ meson to a conserved current. The corrections for the 3-point and 4-point vertex resulting from this are calculated and discussed. Thereafter the physical consequences of the changed self-energy of the ρ meson in nuclear matter are considered. By means of the spectral function it is shown that up to the two-fold of the ground-state density the position of the resonance is nearly not changed. At still higher densities the resonances is a little shifted to higher energies. In the range of an invariant mass of about 400 meV a strong increasement concentrated on a small range results. This is caused by coupling to a naked delta-hole state and a pion. Finally the possibilities are discussed to apply the results of this thesis to the prediction of experimental data. Thereby it is proved to be necessary to base on a simulation of the heavy ion reaction. (orig./HSI) [de

Transition to Δ matter from hot, dense nuclear matter within a relativistic mean field formulation of the nonlinear σ and ω model

International Nuclear Information System (INIS)

Li, Z.; Zhuo, Y.; Li, Z.; Mao, G.; Zhuo, Y.; Mao, G.; Greiner, W.

1997-01-01

An investigation of the transition to Δ matter is performed based on a relativistic mean field formulation of the nonlinear σ and ω model. We demonstrate that in addition to the Δ-meson coupling, the occurrence of the baryon resonance isomer also depends on the nucleon-meson coupling. Our results show that for the favored phenomenological value of m * and K, the Δ isomer exists at baryon density ∼2 3ρ 0 if β=1.31 is adopted. For universal coupling of the nucleon and Δ, the Δ density at baryon density ∼2 3ρ 0 and temperature ∼0.4 0.5 fm -1 is about normal nuclear matter density, which is in accord with a recent experimental finding. copyright 1997 The American Physical Society

Photoproduction of mesons on the nucleon at intermediate energies; Photoproduction de mesons sur le nucleon aux energies intermediaires

Energy Technology Data Exchange (ETDEWEB)

Guidal, M

1997-01-01

In this work a model is proposed to simulate the photoproduction of pseudoscalar mesons ('PI' and K) on the nucleon at high energy. This model is based on the exchange of mesonic or baryonic Regge trajectories, it is gauge invariant and it uses a Feynman diagram formalism inspired from isobaric models. The measurements concerning the following reactions {gamma}p {yields} n{pi}{sup +}, {gamma}n {yields} p{pi}{sup -}, {gamma}p {yields} p{pi}{sup 0} and {gamma}n {yields} n{pi}{sup 0} are reviewed and the new model is confronted to the experimental results. The model gives a reasonable and coherent description of these 4 reactions. The model has also been applied to the photoproduction of strange mesons and of {lambda} and {sigma} baryons and has been extrapolated at low energy to the threshold of the reaction, the model matches the results even up to E{sub {gamma}} = 2 GeV for differential cross-sections and recoil polarization. An attempt has been made to associate a Regge based description, which is valid with low transfers, with perturbative quantum chromodynamics which is valid with high transfers. The model relies on the saturation of trajectories in the high transfer region and on the counting laws that give the right variation of the cross-section. It seems that a model based on linear trajectories can be reliable up to 4 GeV. The domain of high transfer has been too little investigated to provide enough experimental data to validate the model. An experiment whose purpose is to study the photoproduction of {phi} at high transfer, is proposed. This experiment requires an accelerator with high useful cycle because of the smallness of the expected cross-section. The CEBAF (continuous electron beam accelerator facility) as well as the CLAS 4{pi} detector is presented. The study of {gamma}p {yields} p{phi} and {gamma}p {yields} K{lambda}{sup *} (1520) requires the discrimination of kaons from pions so the measurement of 180 ps as time resolution allows the

Temperature-dependent relativistic microscopic optical potential and the mean free path of a nucleon based on Walecka's model

International Nuclear Information System (INIS)

Han Yinlu; Shen Qingbiao; Zhuo Yizhong

1994-01-01

The relativistic microscopic optical potential, the Schroedinger equivalent potential, and mean free paths of a nucleon at finite temperature in nuclear matter and finite nuclei are studied based on Walecka's model and thermo-field dynamics. We let only the Hartree-Fock self-energy of a nucleon represent the real part of the microscopic optical potential and the fourth order of meson exchange diagrams, i.e. the polarization diagrams represent the imaginary part of the microscopic optical potential in nuclear matter. The microscopic optical potential of finite nuclei is obtained by means of the local density approximation. (orig.)

Parametrization of the nucleon-trinucleon overlap function in 4He and the effect of meson exchange corrections

International Nuclear Information System (INIS)

Greben, J.M.

1982-04-01

Nucleon-trinucleon overlap functions in 4 He have been parametrized as a sum of exponentials, and are fitted to the charge form factor of 4 He. We present results with and without taking account of meson-exchange corrections

Mass shift of σ-meson in nuclear matter

International Nuclear Information System (INIS)

Morones-Ibarra, J.R.; Maciel, Mónica Menchaca; Padilla, Felipe Robledo; Santos-Guevara, Ayax

2013-01-01

The propagation of σ-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of σ-ω mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the σ-meson mass decreases with respect to its value in vacuum and that the contribution of the σ-ω mixing effect on the mass shift is relatively small. (author)

Meson (photo- and) electro-production and the structure of nuclei at short distances

International Nuclear Information System (INIS)

Laget, J.M.

1985-09-01

The present status and the future prospects of the studies of very inelastic electronuclear reaction are reviewed, when both high energy and high momentum are transferred to the nucleus. Real and virtual mesons are tested on the same footing. Real meson production allows us to study the propagation of baryonic and mesonic resonances in nuclei and to put constraints on their interaction with the nucleon. Virtual meson creation is an alternative way to deal with exchange currents. The first lecture deals with the elementary operators, which describe meson photo- and electroproduction on free nucleons. The second one deals with real meson- photo- and electroproduction on few-body systems. Only the main features are discussed here and the last developments are presented. The third lecture deals with the coupling of the electromagnetic probe to the virtual meson in nuclei. The emphasis is put on the few-body systems, since their nuclear wave functions are known and since they are simple enough to allow for elaborate calculations. The case of heavy nuclei is also discussed. In the last lecture, I will try to look for evidence of the limits and the breakdown of the description of nuclei in terms of nucleons and mesons, and to forecast the new developments

Electromagnetic Studies of Mesons, Nucleons, and Nuclei

Energy Technology Data Exchange (ETDEWEB)

Baker, Oliver K.

2013-08-20

Professor Baker was a faculty member at Hampton University in Hampton, Virginia, and, jointly, a Staff Physicist at Jefferson Lab in nearby Newport News from September 1989 to July 2006. The Department of Energy (DOE) funded the grant DE-FG02-97ER41035 Electromagnetic Studies of Mesons, Nucleons, and Nuclei, while Baker was in this joint appointment. Baker sent a closeout report on these activities to Hampton University’s Sponsored Research Office some years ago, shortly after joining Yale University in 2006. In the period around 2001, the research grant with Baker as the Principal Investigator (PI) was put under the supervision of Professor Liguang Tang at Hampton University. Baker continued to pursue the research while in this join appointment, however the administrative responsibilities with the DOE and with Hampton University rested with Professor Tang after 2001, to my recollection. What is written in this document is from Baker’s memory of the research activities, which he has not pursued since joining the Yale University faculty.

Quark-flavor mixing and the nucleon strangeness form factors

International Nuclear Information System (INIS)

Ito, H.

1995-01-01

We have calculated the strangeness form factors of the nucleon G E s (Q), G M s (Q) and G A s (Q) and the electromagnetic form factors G E N (Q) as well, by using a relativistic constituent quark model of the nucleon wave function on the light-cone. Octet of Goldstone bosons (π, K, η) are assumed to induce the SU flavor mixing among the light constituent quarks; d-→K+s →d for example, and this mechanism induces the strangeness content in the nucleon. To calculate the meson-loop corrections to the electroweak couplings of constituent quarks, we have employed two models of the quark-meson vertex; (1) composite model of the Goldstone bosons (2) and (3) chiral quark Lagrangian. The loop momenta are regulated in a gauge-invariant way for both models

Study of the production mechanism of the η meson in proton-proton collisions by means of analysing power measurements

International Nuclear Information System (INIS)

Czyzykiewicz, R.

2007-02-01

The analysing power measurements for the #vector#pp→ppη reaction studied in this dissertation are used in the determination of the reaction mechanism of the η meson production in nucleon-nucleon collisions. Measurements have been performed in the close-to-threshold energy region at beam momenta of p beam =2.010 and 2.085 GeV/c, corresponding to the excess energies of Q=10 and 36 MeV, respectively. The experiments were realised by means of a cooler synchrotron and storage ring COSY along with a cluster jet target. For registration of the reaction products the COSY-11 facility has been used. The identification of the η meson has been performed with the missing mass method. The results for the angular dependence of the analysing power combined with the hitherto determined isospin dependence of the total cross section for the η meson production in the nucleon-nucleon collisions, reveal a statistically significant indication that the excitation of the nucleon to the S 11 resonance, the process which intermediates the production of the η meson, is predominantly due to the exchange of a π meson between the colliding nucleons. The determined values of the analysing power at both excess energies are consistent with zero implying that the η meson is produced predominantly in the s-wave at both excess energies. (orig.)

Temperature-dependent cross sections for meson-meson nonresonant reactions in hadronic matter

International Nuclear Information System (INIS)

Zhang Yiping; Xu Xiaoming; Ge Huijun

2010-01-01

We present a potential of which the short-distance part is given by one gluon exchange plus perturbative one- and two-loop corrections and of which the large-distance part exhibits a temperature-dependent constant value. The Schroedinger equation with this temperature-dependent potential yields a temperature dependence of the mesonic quark-antiquark relative-motion wave function and of meson masses. The temperature dependence of the potential, the wave function and the meson masses brings about temperature dependence of cross sections for the nonresonant reactions ππ→ρρ for I=2, KK→K*K* for I=1, KK*→K*K* for I=1, πK→ρK* for I=3/2, πK*→ρK* for I=3/2, ρK→ρK* for I=3/2 and πK*→ρK for I=3/2. As the temperature increases, the rise or fall of peak cross sections is determined by the increased radii of initial mesons, the loosened bound states of final mesons, and the total-mass difference of the initial and final mesons. The temperature-dependent cross sections and meson masses are parametrized.

Probing of the isospin-dependent mean field and nucleon-nucleon cross section in a medium by nucleon emissions

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

Meson exchange corrections in deep inelastic scattering on deuteron

International Nuclear Information System (INIS)

Kaptari, L.P.; Titov, A.I.

1989-01-01

Starting with the general equations of motion of the nucleons interacting with the mesons the one-particle Schroedinger-like equation for the nucleon wave function and the deep inelastic scattering amplitude with the meson-exchange currents are obtained. Effective pion-, sigma-, and omega-meson exchanges are considered. It is found that the mesonic corrections only partially (about 60%) restore the energy sum rule breaking because of the nucleon off-mass-shell effects in nuclei. This results contradicts with the prediction based on the calculation of the energy sum rule limited by the second order of the nucleon-meson vertex and static approximation. 17 refs.; 3 figs

SU(4) flavor symmetry breaking in D-meson couplings to light hadrons

Energy Technology Data Exchange (ETDEWEB)

Fontoura, C.E. [Instituto Tecnologico da Aeronautica, DCTA, Sao Jose dos Campos, SP (Brazil); Universidade Estadual Paulista, Instituto de Fisica Teorica, Sao Paulo, SP (Brazil); Haidenbauer, J. [Institute for Advanced Simulation, Institut fuer Kernphysik, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Juelich (Germany); Krein, G. [Universidade Estadual Paulista, Instituto de Fisica Teorica, Sao Paulo, SP (Brazil)

2017-05-15

The validity of SU(4)-flavor symmetry relations of couplings of charmed D-mesons to light mesons and baryons is examined with the use of {sup 3}P{sub 0} quark-pair creation model and nonrelativistic quark-model wave functions. We focus on the three-meson couplings ππρ, KKρ and DDρ and baryon-baryon-meson couplings NNπ, NΛK and NΛ{sub c}D. It is found that SU(4)-flavor symmetry is broken at the level of 30% in the DDρ tree-meson couplings and 20% in the baryon-baryon-meson couplings. Consequences of these findings for DN cross sections and existence of bound states D-mesons in nuclei are discussed. (orig.)

Covariant density functional theory for nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Badarch, U.

2007-07-01

The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)

Covariant density functional theory for nuclear matter

International Nuclear Information System (INIS)

Badarch, U.

2007-01-01

The present thesis is organized as follows. In Chapter 2 we study the Nucleon-Nucleon (NN) interaction in Dirac-Brueckner (DB) approach. We start by considering the NN interaction in free-space in terms of the Bethe-Salpeter (BS) equation to the meson exchange potential model. Then we present the DB approach for nuclear matter by extending the BS equation for the in-medium NN interaction. From the solution of the three-dimensional in-medium BS equation, we derive the DB self-energies and total binding energy which are the main results of the DB approach, which we later incorporate in the field theoretical calculation of the nuclear equation of state. In Chapter 3, we introduce the basic concepts of density functional theory in the context of Quantum Hadrodynamics (QHD-I). We reach the main point of this work in Chapter 4 where we introduce the DDRH approach. In the DDRH theory, the medium dependence of the meson-nucleon vertices is expressed as functionals of the baryon field operators. Because of the complexities of the operator-valued functionals we decide to use the mean-field approximation. In Chapter 5, we contrast microscopic and phenomenological approaches to extracting density dependent meson-baryon vertices. Chapter 6 gives the results of our studies of the EOS of infinite nuclear matter in detail. Using formulas derived in Chapters 4 and 5 we calculate the properties of symmetric and asymmetric nuclear matter and pure neutron matter. (orig.)

Scalar meson field and many-body forces. Chapter 23

International Nuclear Information System (INIS)

Nyman, E.M.

1979-01-01

In applications of field theory to the theory of the nuclear forces, one has frequently assumed that there is a scalar meson. It will then be responsible for most of the medium-range attraction between the nucleons. According to current ideas, however, it is possible to account for the medium-range attraction without an elementary sigma meson. This approach requires a careful treatment of the exchange of interacting pairs of π mesons, such as to include those ππ interactions which are responsible for the formation and decay of the sigma meson. Recently, the scalar field in the nuclear many-body problem has begun to receive more attention. There are two reasons for this change of philosophy. One reason is the discovery of neutron stars. In neutron stars, the nucleon number density can be much higher than in nuclei. One therefore wants to derive the equation of state from a relativistic many-body theory. This forces one to deal explicitly with a set of mesons, such that in the non-relativistic limit one recovers the one-boson-exchange potential. (Auth.)

Parity violating nuclear force by meson mixing

International Nuclear Information System (INIS)

Iqbal, M.J.; Niskanen, J.A.

1990-01-01

We study a mechanism for parity violation in the two nucleon meson-exchange interaction by way of the mixing of mesons of opposite parities. This mixing arises from parity violating W ± and Z exchange between the q bar q pair in the meson. Numerically its effect turns out to be as important as vector meson exchange with a weak meson-nucleon vertex and may partly be used to model this vertex. The calculation is performed using both the standard Born approximation adding the amplitude phases by Watson's theorem and also using the exact correlated two-nucleon wave functions. The effect of correlations and form factors is found to be crucially important at intermediate energies

The hyperon-nucleon interaction

International Nuclear Information System (INIS)

Haidenbauer, J.

2007-01-01

Results of two recent hyperon-nucleon interaction potentials, both developed by the Bonn-Juelich group, are presented that are derived either in the conventional meson-exchange picture or within leading order chiral effective field theory. The chiral potential consists of one-pseudoscalar-meson exchanges and non-derivative four-baryon contact terms. The most salient feature of the new meson-exchange hyperon-nucleon model is that the contributions in the scalar-isoscalar (σ) and vector-isovector (ρ) exchange channels are constrained by a microscopic model of correlated ππ and KK-bar exchange

Zero-point motion in the bag description of the nucleon

International Nuclear Information System (INIS)

Brown, G.E.; Durso, J.W.; Johnson, M.B.

1983-01-01

In the bag model, confinement of quarks is accomplished by introduction of a boundary condition at some definite radius R, where the energy of the total system is a minimum. This minimum is, however, relatively shallow and energies for substantially different bag radii are not much larger than this minimum value. This indicates that the zero-point motion of the bag surface may be important. In this paper, quantization of the bag surface motion is carried out in a somewhat ad hoc fashion, modelled after the generator coordinate theory in nuclear physics. This procedure unifies a number of ideas previously in the literature; it stresses the anharmonicity of the collective motion. As in earlier treatments, the Roper resonance emerges as a breathing-mode type of excitation of the nucleon. The one- and two-pion decays of the Roper resonance are calculated and the widths are found to fall short of the empirical ones. It is pointed out, however, that decays involving intermediate states containing virtual rho-mesons will enhance the widths. Pion-nucleon scattering in the P 11 channel is constructed in our model and found to agree roughly with experiment. A crucial term in the driving force involves the pion coupling to the nucleon through a virtual rho-meson. With introduction of zero-point motion of the bag surface, the motion of 'bag radius' becomes dependent on precisely which moment of the radius is measured. Our development gives a model for cutting off smoothly the pion-exchange term in the nucleon-nucleon interaction. (orig.)

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

International Nuclear Information System (INIS)

Fuchs, M.

1993-01-01

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

Oscillations of the static meson fields at finite baryon density

International Nuclear Information System (INIS)

Florkowski, W.; Friman, B.; Technische Hochschule Darmstadt

1996-04-01

The spatial dependence of static meson correlation functions at finite baryon density is studied in the Nambu-Jona-Lasinio model. In contrast to the finite temperature case, we find that the correlation functions at finite density are not screened but exhibit long-range oscillations. The observed phenomenon is analogous to the Friedel oscillations in a degenerate electron gas. (orig.)

Microscopic nuclear structure with sub-nucleonic degrees of freedom

International Nuclear Information System (INIS)

Sauer, P.U.

1986-01-01

The paper reviews microscopic theories of nuclear structure. The subject is discussed under the topic headings: microscopic nuclear structure with nucleons only; microscopic nuclear structure with nucleons, isobars and mesons; and microscopic nuclear structure with nucleons, mesons and dibaryons. (U.K.)

11th Workshop on The Physics of Excited Nucleons

CERN Document Server

Hammer, Hans-Werner; Thoma, Ulrike; Schmieden, Hartmut; NSTAR 2007

2008-01-01

The excitation spectrum of the nucleon promises to offer important insights into the non-perturbative regime of QCD. Dedicated experimental programs at various laboratories exist to perform accurate measurements of meson photo- and electroproduction off the nucleon, studying its excitation. The NStar workshops are a well-established series of meetings that bring together experimenters and theoreticians working on baryon resonances and related areas to discuss New results on pseudoscalar and vector meson production; Partial wave analysis and resonance parameters; Baryon resonance structure and quark models; Dynamical models and coupled channel analysis; Baryon resonances in lattice QCD; Chiral symmetry and baryon resonances; Laboratory reports and future projects. The refereed and edited proceedings constitute an indispensable archival record of the progress in the field.

Direct Measurement of the Gluon Polarisation in the Nucleon via Charmed Meson Production

CERN Document Server

Alekseev, M; Alexandrov, Yu; Alexeev, G D; Amoroso, A; Arbuzov, A; Badelek, Barbara Maria; Balestra, F; Ball, J; Barth, J; Baum, Guenter; Bedfer, Y; Bernet, Colin; Bertini, R; Bettinelli, M; Birsa, R; Bisplinghoff, J; Bordalo, P; Bradamante, Franco; Brona, G; Burtin, E; Bussa, M P; Chapiro, A; Chiosso, M; Cicuttin, A; Colantoni, M; Crespo, M L; Dalla Torre, S; Dafni, T; Das, S; Dasgupta, S S; De Masi, R; Dedek, N; Dhara, L; Diaz, V; Dinkelbach, A M; Donskov, S V; Dorofeev, V A; Doshita, N; Duic, V; Dunnweber, W; Eversheim, P D; Eyrich, W; Faessler, M; Falaleev, V; Ferrero, L; Finger, M; Finger, M., Jr; Fischer, H; Franco, C; Franz, J; Friedrich, J M; Garfagnini, R; Gautheron, Fabrice; Gavrichtchouk, O P; Gazda, R; Geyer, R; Giorgi, M; Gobbo, Benigno; Gorin, A M; Grabmuller, S; Grajek, O A; Grasso, A; Grube, B; Gushterski, R; Guskov, A; Haas, F; Hannappel, J; von Harrach, D; Hasegawa, T; Heckmann, J; Hedicke, S; Heinsius, Fritz-Herbert; Hermann, R; Hess, C; Hinterberger, F; von Hodenberg, M; Horikawa, S; d'Hose, N; Ilgner, C; Ioukaev, A I; Ishimoto, S; Ivanov, O; Ivanshin, Yu; Jahn, R; Janata, A; Jasinski, P; Joosten, R; Jouravlev, N I; Kabuss, E; Kang, D; Ketzer, Bernhard; Khaustov, G V; Khokhlov, Yu A; Klein, F; Klimaszewski, K; Koblitz, S; Kolosov, V N; Komissarov, E V; Kondo, K; Konigsmann, Kay; Konstantinov, V F; Korentchenko, A S; Koutchinski, N A; Kral, A; Kravchuk, N P; Kroumchtein, Z V; Kuhn, R; Kunne, Fabienne; Kurek, Krzysztof; Ladygin, M E; Le Goff, Jean-Marc; Lednev, A A; Lehmann, A; Levorato, S; Lichtenstadt, J; Liska, T; Ludwig, I; Maggiora, A; Maggiora, M; Magnon, A; Mallot, G K; Mann, A; Marchand, C; Marroncle, J; Martin, A; Marzec, J; Massmann, F; Matsuda, T; Meyer, W.Thomas; Mikhailov, Yu V; Moinester, M A; Nagaytsev, A; Nagel, T; Nahle, O; Nassalski, J; Neliba, S; Nerling, F; Neubert, S; Neyret, D P; Nikolaenko, V I; Nikolaev, K; Olshevsky, A G; Ostrick, M; Padee, A; Pagano, P; Panebianco, S; Panknin, R; Panzieri, D; Paul, S; Pawlukiewicz-Kaminska, B; Peshekhonov, D V; Peshekhonov, V D; Piragino, G; Platchkov, Stephane; Pochodzalla, J; Polak, J; Polyakov, V A; Pretz, J; Procureur, S; Quintans, C; Rajotte, J F; Ramos, S.; Rapatsky, V; Reicherz, G; Reggiani, D; Richter, A; Robinet, F; Rondio, Ewa; Rozhdestvensky, A M; Ryabchikov, D I; Samoylenko, V D; Sandacz, A; Sapozhnikov, M G; Sarkar, S; Savin, Igor A; Schiavon, P; Schill, Christian; Schonmeier, P; Schroder, W; Shevchenko, O Yu; Silva, L; Sinha, L; Sissakian, A N; Slunecka, M; Smirnov, G I; Sosio, S; Sozzi, F; Srnka, A; Stinzing, F; Sugonyaev, V P; Sulc, M; Sulej, R; Tchalishev, V V; Tessaro, S; Tessarotto, F; Teufel, A; Tkatchev, L G; Venugopal, G; Virius, M; Vlassov, N V; Vossen, A; Webb, Robert C; Weitzel, Q; Windmolders, R; Wirth, S; Wislicki, W; Wollny, H; Zaremba, K; Zavertyaev, M; Zemlyanichkina, E; Ziegler, R; Zvyagin, A

2008-01-01

We present the first measurement of the gluon polarisation in the nucleon based on the photon-gluon fusion process tagged by charmed meson production and decay to charged K and pi. The data were collected in polarised muon scattering off a polarised deuteron target by the COMPASS collaboration at CERN during 2002-2004. The result of this LO analysis is _x = -0.47 +- 0.44 (stat) +- 0.15 (syst) at ~= 0.11 and a scale mu^2 ~ 13 (GeV/c)^2.

The mixing of scalar mesons and the baryon-baryon interaction

International Nuclear Information System (INIS)

Dai, L.R.

2011-01-01

By introducing the mixing of scalar mesons in the chiral SU(3) quark model, we dynamically investigate the baryon-baryon interaction. The hyperon-nucleon and nucleon-nucleon interactions are studied by solving the resonating group method (RGM) equation in a coupled-channel calculation. In our present work, the experimental lightest pseudoscalar π, K, η, η' mesons correspond exactly to the chiral nonet pseudoscalar fields π, K, η, η' in the chiral SU(3) quark model. The η, η' mesons are considered as the mixing of singlet and octet mesons, and the mixing angle θ ps is taken to be -23 . For scalar nonet mesons, we suppose that there exists a correspondence between the experimental lightest scalar f 0 (600), κ, a 0 (980), f 0 (980) mesons and the theoretical scalar nonet σ, κ, σ', ε fields in the chiral SU(3) quark model. For scalar mesons, we consider two different mixing cases: one is the ideal mixing and another is the θ s = 19 mixing. The masses of the σ' and ε mesons are taken to be 980MeV, which are just the masses of the experimental a 0 (980), f 0 (980) mesons. The mass of the σ meson is an adjustable parameter and is decided by fitting the binding energy of the deuteron, the masses of 560MeV and 644MeV are obtained for the ideal mixing and the θ s = 19 mixing, respectively. We find that, in order to reasonably describe the YN interactions, the mass of the κ meson is near 780MeV for the ideal mixing. However, we must enhance the mass of the κ meson for the θ s = 19 mixing, the 1050MeV is favorably used in the present work. The experimental σ and κ scalar mesons are very strange, both have larger widths. Hence, no matter what kind of mixing is considered, all the masses of scalar mesons we used in the present work seem to be consistent with the present PDG information. (orig.)

First measurement of the gluon polarisation in the nucleon using D mesons at COMPASS

CERN Document Server

von Hodenberg, Martin

2005-01-01

The complicated structure of the nucleon has been studied with great success in deep-inelastic lepton-nucleon scattering (DIS) experiments at CERN, SLAC and DESY. As a result the unpolarised structure functions have been measured accurately over a wide kinematic range. From these measurements it is possible to determine the gluon density in the nucleon with good accuracy via a so-called QCD fit. In the case of the spin structure of the nucleon the situation is different. Even after decades of experimental and theoretical efforts it remains to be understood how the spin of the nucleon of 1/2 in units of h-bar is to be accounted for in terms of contributions from the quarks and gluons inside the nucleon. Of particular interest is the question whether the polarised gluon density can explain the unexpected smallness of the quark contribution to the nucleon spin. The QCD fit, which worked well in the unpolarised case, yields a polarised gluon density Delta G which is only badly constrained. This is due to the fact...

The nucleon as a projected chiral soliton: vacuum and medium properties

International Nuclear Information System (INIS)

Fiolhais, M.; Alberto, P.; Ruiz Arriola, E.; Christov, C.V.; Bylgarska Akademiya na Naukite, Sofia

1990-01-01

Nucleon properties and nucleon form factors are computed within the framework of the projected linear chiral soliton model. To this end the Gell-Mann - Levy lagrangian is solved by means of variational methods which include angular momentum and isospin projection with trial quark-boson Fock states in generalized hedgehog configurations. The consistency of the treatment is checked by the fulfillment of virial theorems such as Goldberger-Treiman relation. In general the q 2 dependence of the nucleon form factors are well described although some of their values at zero momentum transfer come out too large, namely for the axial- and πN N- form factors. Electromagnetic form factors for the N - Δ transition are also calculated and compared with the available experimental data. Medium effects on the nucleon properties are investigated combining the projected chiral soliton model with the Nambu-Jona-Lasinio model. The latter is employed to compute the pion decay constant and the pion and sigma masses at finite medium density. These meson properties fix the parameters in the linear sigma model, which is then solved using the same variational methods as for the zero density. The nucleon mass shows a decrease of 17% and the proton radius an increase of 19% if the medium reaches nuclear matter density. The magnetic moments and g A are less affected by the medium. The nucleon electromagnetic form factors show remarkable changes at finite transfer numbers as well. (author)

σ and ρ meson strength distributions from in medium corrected ππ correlations and the nuclear equation of state

International Nuclear Information System (INIS)

Chanfray, G.; Aouissat, Z.; Schuck, P.; Norenberg, W.

1990-01-01

The most important part of the intermediate range nucleon-nucleon attraction is attributed to the exchange of non interacting as well as interaction two pions in the I = J = O channel. The corresponding 2π exchange potential, or part of it, is often simulated by a sigma-meson exchange with mass of about 600 MeV, which is then used as a basic input to nuclear matter calculation. This may give in particular a justification to the popular σ-ψ model. However a number of question remains concerning the microscopic nature of such an effective sigma meson. The point the authors want to emphasize in this paper concerns the possible modification of the sigma in the medium since they think that it is made out of pions whose propagations are strongly altered by the medium. However also the ρ-meson may undergo similar in medium corrections which possibly are related to recent experimental findings. The authors discuss, with a very simple model, the problem of pion propagation and pion-pion interaction in the medium and the occurrence of highly collective pion-delta modes (pionic branch, pisobar, quasi pion) in agreement with experimental data. They also should have some very important consequences on the dynamics of relativistic heavy collision. The authors address the very important question of the nuclear matter equation of state where collective pionic effects are included to reconstruct an effective sigma exchange whose mass and coupling constant are density dependent

Hyperon interaction in free space and nuclear matter within a SU(3) based meson exchange model

Energy Technology Data Exchange (ETDEWEB)

Dhar, Madhumita

2016-06-15

To establish the connection between free space and in-medium hyperon-nucleon interactions is the central issue of this thesis. The guiding principle is flavor SU(3) symmetry which is exploited at various levels. In first step hyperon-nucleon and hyperon- hyperon interaction boson exchange potential in free space are introduced. A new parameter set applicable for the complete baryon octet has been derived leading to an updated one-boson- exchange model, utilizing SU(3) flavor symmetry, optimizing the number of free parameters involved, and revising the set of mesons included. The scalar, pseudoscalar, and vector SU(3) meson octets are taken into account. T-matrices are calculated by solving numerically coupled linear systems of Lippmann-Schwinger equations obtained from a 3-D reduced Bethe-Salpeter equation. Coupling constants were determined by χ{sup 2} fits to the world set of scattering data. A good description of the few available data is achieved within the imposed SU(3) constraints. Having at hand a consistently derived vacuum interaction we extend the approach next to investigations of the in-medium properties of hyperon interaction, avoiding any further adjustments. Medium effect in infinite nuclear matter are treated microscopically by recalculating T-matrices by an medium-modified system of Lippmann-Schwinger equations. A particular important role is played by the Pauli projector accounting for the exclusion principle. The presence of a background medium induces a weakening of the vacuum interaction amplitudes. Especially coupled channel mixing is found to be affected sensitively by medium. Investigation on scattering lengths and effective range parameters are revealing the density dependence of the interaction on a quantitative level.

Oscillations of the static meson fields at finite baryon density

International Nuclear Information System (INIS)

Florkowski, W.; Friman, B.; Technische Hochschule Darmstadt

1996-04-01

The spatial dependence of static meson correlation functions at finite baryon density is studied in the Nambu-Jona-Lasinio model. In contrast to the finite temperature case, we find that the correlation functions at finite density are not screened but exhibit long-range oscillations. The observed phenomenon is analogous to the Friedel oscillations in a degenerate electron gas. (author). 19 refs, 6 figs

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.)

Time Evolution of Meson Density During Formation of Expanding Quark-Antiquark System

Science.gov (United States)

Ghaffary, Tooraj

2018-04-01

Recently some researchers (Sepehri and Shoorvazi Astrophys. Spaces Sci. 344(2), 521-527, 2013) have considered the Universe as an acceleration cylindrical system. Motivated by their work and using their method in QCD, this paper has been cleared that because the acceleration of expansion in quark-antiquark system is relatively very large, one horizon is appeared outside the system. To obtain the total cross section of meson near this horizon, we need to multiply the production cross section for appeared horizon by the density of meson produced outside the system. As it can be seen by an observer who is outside the meson formation process, this cross section depends on time so the event horizon is now a time depended process.

Meson phase space density from interferometry

International Nuclear Information System (INIS)

Bertsch, G.F.

1993-01-01

The interferometric analysis of meson correlations a measure of the average phase space density of the mesons in the final state. The quantity is a useful indicator of the statistical properties of the systems, and it can be extracted with a minimum of model assumptions. Values obtained from recent measurements are consistent with the thermal value, but do not rule out superradiance effects

In-medium relativistic kinetic theory and nucleon-meson systems

International Nuclear Information System (INIS)

Morawetz, K.; Kremp, D.

1995-01-01

Within the σ-ω model of coupled nucleonmeson systems, a generalized relativistic Lennard-Balescu-equation is presented resulting from a relativistic random phase approximation (RRPA). This provides a systematic derivation of relativistic transport equations in the frame of nonequilibrium Green's function technique including medium effects as well as fluctuation effects. It contains all possible processes due to one-meson exchange and special attention is kept to the off-shell character of the particles. As a new feature of many-particle effects, processes are possible, which can be interpreted as particle creation and annihilation due to in-medium one-meson exchange. In-medium cross sections are obtained from the generalized derivation of collision integrals, which possess complete crossing symmetries. (orig.)

General aspects of the nucleon-nucleon interaction and nuclear matter properties

Energy Technology Data Exchange (ETDEWEB)

Plohl, Oliver

2008-07-25

The subject of the present thesis is at first the investigation of model independent properties of the nucleon-nucleon (NN) interaction in the vacuum concerning the relativistic structure and the implications for nuclear matter properties. Relativistic and non-relativistic meson-exchange potentials, phenomenological potentials s well as potentials based on effective field theory (EFT) are therefore mapped on a relativistic operator basis given by the Clifford Algebra. This allows to compare the various approaches at the level of covariant amplitudes where a remarkable agreement is found. Furthermore, the relativistic self-energy is determined in the Hartree-Fock (HF) approximation. The appearance of a scalar and vector field of several hundred MeV magnitude is a general feature of relativistic descriptions of nuclear matter. Within QCD sum rules these fields arise due to the density dependence of chiral condensates. We find that independent of the applied NN interaction large scalar and vector fields are generated when the symmetries of the Lorentz group are restored. In the framework of chiral EFT (chEFT) it is shown, that these fields are generated by short-range next-to-leading order (NLO) contact terms, which are connected to the spin-orbit interaction. To estimate the effect arising from NN correlations the equation of state of nuclear and neutron matter is calculated in the Brueckner-HF (BHF) approximation applying chEFT. Although, as expected, a clear over-binding is found (at NLO a saturating behavior is observed), the symmetry energy shows realistic properties when compared to phenomenological potentials (within the same approximation) and other approaches. The investigation of the pion mass dependence within chEFT at NLO shows that the magnitude of the scalar and vector fields persists in the chiral limit - nuclear matter is still bound. In contrast to the case of a pion mass larger than the physical one the binding energy and saturation density are

General aspects of the nucleon-nucleon interaction and nuclear matter properties

International Nuclear Information System (INIS)

Plohl, Oliver

2008-01-01

The subject of the present thesis is at first the investigation of model independent properties of the nucleon-nucleon (NN) interaction in the vacuum concerning the relativistic structure and the implications for nuclear matter properties. Relativistic and non-relativistic meson-exchange potentials, phenomenological potentials s well as potentials based on effective field theory (EFT) are therefore mapped on a relativistic operator basis given by the Clifford Algebra. This allows to compare the various approaches at the level of covariant amplitudes where a remarkable agreement is found. Furthermore, the relativistic self-energy is determined in the Hartree-Fock (HF) approximation. The appearance of a scalar and vector field of several hundred MeV magnitude is a general feature of relativistic descriptions of nuclear matter. Within QCD sum rules these fields arise due to the density dependence of chiral condensates. We find that independent of the applied NN interaction large scalar and vector fields are generated when the symmetries of the Lorentz group are restored. In the framework of chiral EFT (chEFT) it is shown, that these fields are generated by short-range next-to-leading order (NLO) contact terms, which are connected to the spin-orbit interaction. To estimate the effect arising from NN correlations the equation of state of nuclear and neutron matter is calculated in the Brueckner-HF (BHF) approximation applying chEFT. Although, as expected, a clear over-binding is found (at NLO a saturating behavior is observed), the symmetry energy shows realistic properties when compared to phenomenological potentials (within the same approximation) and other approaches. The investigation of the pion mass dependence within chEFT at NLO shows that the magnitude of the scalar and vector fields persists in the chiral limit - nuclear matter is still bound. In contrast to the case of a pion mass larger than the physical one the binding energy and saturation density are

Relativistic treatment of mesonic contributions to quasielastic (e,e')

International Nuclear Information System (INIS)

Blunden, P.G.; Butler, M.N.

1988-03-01

Meson exchange currents play an important role in the description of observables in electron scattering. The authors use a relativistic model with pseudovector pion coupling to study the exchange current contributions, with emphasis on quasielastic kinematics. Starting with the Lagrangian for nucleons interacting with a scalar and vector mason along with pseudovector coupling to pions, they derive the one and two-body electromagnetic currents. They then calculate the longitudinal and transverse pieces of the quasielastic cross section for various nuclei and kinematics. The effects of meson exchange currents are found to be much more important in a relativistic model than in a non-relativistic one

Effects of Δ baryon in hyperon stars in a modified quark meson coupling model

International Nuclear Information System (INIS)

Sahoo, H.S.; Mishra, R.N.; Panda, P.K.; Barik, N.

2016-01-01

Recent studies on the appearance of the Δ (1232) isobars in neutron stars has ignited much debate on the possibility of its existence in neutron stars satisfying the observational limit of 2 M_⊙. Given the fact that the presence of the Δ tends to soften the equation of state (EoS) and reduce the maximum mass, theoretical and observational contradictions have given rise to the so called Δ puzzle, similar to the hyperon puzzle. In the present work we develop the EoS for dense matter with the inclusion of the nucleons, hyperons and the Delta isobars and study the effects of such inclusion on stellar properties using a Modified Quark-Meson coupling model (MQMC)

Effect of Δ-isobar excitation on spin-dependent observables of elastic nucleon-deuteron scattering

International Nuclear Information System (INIS)

Nemoto, S.; Oryu, S.; Chmielewski, K.; Sauer, P.U.

2000-01-01

Δ-isobar excitation in the nuclear medium yields an effective three-nucleon force. A coupled-channel formulation with Δ-isobar excitation developed previously is used. The three-particle scattering equations are solved by a separable expansion of the two-baryon transition matrix for elastic nucleon-deuteron scattering. The effect of Δ-isobar excitation on the spin-dependent observables is studied at energies above 50 MeV nucleon lab energy. (author)

Nucleon Resonance Physics

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.

Subtracted Dispersion Relations for In-medium Meson Correlators in QCD Sum Rules

Energy Technology Data Exchange (ETDEWEB)

Florkowski, W; Broniowski, W [The H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

1999-01-01

We analyze subtracted dispersion relations for meson correlators at finite baryon density and temperature. Such relations are needed for QCD sum rules. We point out that importance of scattering terms, as well as finite, well-defined subtraction constants. Both are necessary for consistency, in particular for the equality of the longitudinal and transverse correlators in the limit of the vanishing three-momentum of mesons relative to the medium. We present detailed calculations in various mesonic channels of the Fermi gas of nucleons. (author)

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

International Nuclear Information System (INIS)

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

2006-01-01

formation of a short-range repulsive core. In the given work this approach is generalized for constructing effective hadron-hadron interaction operators in framework multichannel formalism in arbitrary angular momentum states taking into account effects of inelasticity. The methods of taking into account mechanisms of formation a quark-gluon compound states in hadron-hadron interactions are elaborated also. The developed methods are applied to constructing nucleon-nucleon interaction operators in different partial-wave states. The boson-exchange model was used to calculate the discontinuities of the partial-wave scattering amplitudes taking into account π, σ, ρ, ω, η, a 0 -meson contributions. The effective nucleon-nucleon potentials in our approach (as against the one-boson-exchange model in usual sense) contain nonlinear contributions on dynamic discontinuities of partial-wave scattering amplitudes, which play essential role at small distances. Note that in realistic Bonn potential model [5] the short-range repulsion is due to ω-meson exchange contribution. It is required in this theory non-realistically large value (≅20 ) of the coupling constant g ωNN 2 /4π. The value of this coupling constant in our approach is consistent with available experimental data [6] and also with theoretical quark-model calculations. The theoretical predictions of the proposed approach are in fairly good agreement with partial-wave-analysis data for laboratory kinetic energies of incident nucleon up to T=1.5-2.0 GeV. The developed approach is applied also to pion-nucleon scattering at kinetic energies of incident pion up to T=2.0 GeV. This work was supported by the Russian Foundation for Basic Research under the project No 04-02-16967. (author)

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.)

The mixing of scalar mesons and the baryon-baryon interaction

Energy Technology Data Exchange (ETDEWEB)

Dai, L.R. [Liaoning Normal University, Department of Physics, Dalian (China)

2011-02-15

By introducing the mixing of scalar mesons in the chiral SU(3) quark model, we dynamically investigate the baryon-baryon interaction. The hyperon-nucleon and nucleon-nucleon interactions are studied by solving the resonating group method (RGM) equation in a coupled-channel calculation. In our present work, the experimental lightest pseudoscalar {pi}, K, {eta}, {eta}' mesons correspond exactly to the chiral nonet pseudoscalar fields {pi}, K, {eta}, {eta}' in the chiral SU(3) quark model. The {eta}, {eta}' mesons are considered as the mixing of singlet and octet mesons, and the mixing angle {theta}{sub ps} is taken to be -23 . For scalar nonet mesons, we suppose that there exists a correspondence between the experimental lightest scalar f{sub 0}(600), {kappa}, a{sub 0}(980), f{sub 0}(980) mesons and the theoretical scalar nonet {sigma}, {kappa}, {sigma}', {epsilon} fields in the chiral SU(3) quark model. For scalar mesons, we consider two different mixing cases: one is the ideal mixing and another is the {theta}{sub s} = 19 mixing. The masses of the {sigma}' and {epsilon} mesons are taken to be 980MeV, which are just the masses of the experimental a{sub 0}(980), f{sub 0}(980) mesons. The mass of the {sigma} meson is an adjustable parameter and is decided by fitting the binding energy of the deuteron, the masses of 560MeV and 644MeV are obtained for the ideal mixing and the {theta}{sub s} = 19 mixing, respectively. We find that, in order to reasonably describe the YN interactions, the mass of the {kappa} meson is near 780MeV for the ideal mixing. However, we must enhance the mass of the {kappa} meson for the {theta}{sub s} = 19 mixing, the 1050MeV is favorably used in the present work. The experimental {sigma} and {kappa} scalar mesons are very strange, both have larger widths. Hence, no matter what kind of mixing is considered, all the masses of scalar mesons we used in the present work seem to be consistent with the present PDG information

Exploring the Quark-Gluon Content of Hadrons: From Mesons to Nuclear Matter

International Nuclear Information System (INIS)

Hrayr Matevosyan

2007-01-01

Even though Quantum Chromodynamics (QCD) was formulated over three decades ago, it poses enormous challenges for describing the properties of hadrons from the underlying quark-gluon degrees of freedom. Moreover, the problem of describing the nuclear force from its quark-gluon origin is still open. While a direct solution of QCD to describe the hadrons and nuclear force is not possible at this time, we explore a variety of developed approaches ranging from phenomenology to first principle calculations at one or other level of approximation in linking the nuclear force to QCD. The Dyson Schwinger formulation (DSE) of coupled integral equations for the QCD Green's functions allows a non-perturbative approach to describe hadronic properties, starting from the level of QCD n-point functions. A significant approximation in this method is the employment of a finite truncation of the system of DSEs, that might distort the physical picture. In this work we explore the effects of including a more complete truncation of the quark-gluon vertex function on the resulting solutions for the quark 2-point functions as well as the pseudoscalar and vector meson masses. The exploration showed strong indications of possibly large contributions from the explicit inclusion of the gluon 3- and 4-point functions that are omitted in this and previous analyses. We then explore the possibility of extrapolating state of the art lattice QCD calculations of nucleon form factors to the physical regime using phenomenological models of nucleon structure. Finally, we further developed the Quark Meson Coupling model for describing atomic nuclei and nuclear matter, where the quark-gluon structure of nucleons is modeled by the MIT bag model and the nucleon many body interaction is mediated by the exchange of scalar and vector mesons. This approach allows us to formulate a fully relativistic theory, which can be expanded in the nonrelativistic limit to reproduce the well known phenomenological Skyrme

Physics with ETA mesons

International Nuclear Information System (INIS)

Liu, Lon-chang.

1989-01-01

Since the advent of pion factories, an impressive amount of information about the nuclear dynamics of the Δ(1232) pion- nucleon resonance has been obtained. The study of this isospin-3/2 resonance has greatly benefited from the fact that π/sup /minus//n and π + p systems are pure I = 3/2 states, which couple only to the Δ in the resonance region. Such isospin selectivity of the pion does not exist, however, for the I = 1/2 N* resonances because it is not possible to form a pure I = 1/2 state with a pion and a nucleon. Eta mesons have zero isospin. Consequently, the /eta/N systems are in a pure I = 1/2 state, and /eta/ can be used to tag those N* resonances to which it strongly couples. We will briefly review the πN interaction from the threshold region to c.m. energy √s ≅1600 MeV. We shall see how improved πN data can help the study of πN interactions. I shall discuss what new information about the hadronic interaction can be learned from the study of eta production in pp collisions. The behavior of eta meson in nuclei will be discussed. The interesting question of the quark structure of /eta/(549) and /eta/'(958) will also be discussed within the framework of a simple model. 19 refs., 13 figs

Nucleon-nucleon interaction and the quark model

International Nuclear Information System (INIS)

Faessler, A.

1985-01-01

The NN phase shifts are calculated using the quark model with a QCD inspired quark-quark force. The short range part of the NN force is given by quark and gluon exchange. The long range part is described by π and σ-meson exchange. The data fitted in the model are five values connected with three quarks only: the nucleon mass, the Δ mass, the root mean square radius of the charge distribution of the proton including the pion cloud, the π-N and the σ-N coupling constant at zero momentum transfer. The 1 S and 3 S phase shifts are nicely reproduced. The short range repulsion is decisively influenced by the node in the [42] r relative wave function. Very important is the colour magnetic quark-quark force which enlarges the [42] r admixture. In the OBEP's the short range repulsion is connected with the exchange of the ω-meson. But to reproduce the short range repulsion one had to blow up the ω-N coupling constant by a factor 2 to 3 compared to flavour SU 3 . With quark and gluon exchange the best fit to the ω-N coupling constant lies close to the SU 3 flavour value. This fact strongly supports the notion that the real nature of the short range repulsion of the NN interaction have been found

Finite nuclei in relativistic models with a light chiral scalar meson

International Nuclear Information System (INIS)

Serot, B.D.; Furnstahl, R.J.

1993-01-01

Relativistic chiral models with a light scalar, meson appear to provide an economical marriage of successful relativistic mean-field theories and chiral symmetry. In these models, the scalar meson serves as both the chiral partner of the pion and the mediator of the intermediate-range nucleon-nucleon (NN) attraction. However, while some of these models can reproduce the empirical nuclear matter saturation point, they fail to reproduce observed properties of finite nuclei, such as spin-orbit splittings, shell structure, charge densities, and surface energetics. There deficiencies imply that this realization of chiral symmetry is incorrect. An alternative scenario for chiral hadronic models, which features a heavy chiral scalar and dynamical generation of the NN attraction, is discussed

The Rainich problem for coupled gravitational and scalar meson fields

International Nuclear Information System (INIS)

Hyde, J.M.

1975-01-01

The equations of the coupled gravitational and scalar meson fields in general relativity are considered. It is shown that the wave equation for the scalar meson field which is usually specified explicitly in addition to the Einstein field equations is implied by Einstein's equations. Using this result it is then shown how the scalar field may be eliminated explicitly from the field equations, thus solving the Rainich problem for the coupled gravitational and scalar meson fields. (author) [fr

Fock exchange in meson theories of nuclei

International Nuclear Information System (INIS)

Bolsterli, M.

1986-01-01

The Fock exchange term in meson field theories of nuclear systems is shown to arise from a two-loop ground-state self-energy diagram. Evaluation of this diagram gives the relativistic or semirelativistic analog of the Fock exchange energy; it differs from the nucleon-nucleon Fock energy in including retardation effects. In finite meson-field theories of nuclear systems, the variational nature of the meson-field analog of the Hartree-Fock energy functional can be further elucidated. 4 refs

NEW HYPERON EQUATIONS OF STATE FOR SUPERNOVAE AND NEUTRON STARS IN DENSITY-DEPENDENT HADRON FIELD THEORY

Energy Technology Data Exchange (ETDEWEB)

Banik, Sarmistha [BITS Pilani, Hyderabad Campus, Hyderabad-500078 (India); Hempel, Matthias [Departement Physik, Universität Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Bandyopadhyay, Debades [Astroparticle Physics and Cosmology Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata-700064 (India)

2014-10-01

We develop new hyperon equation of state (EoS) tables for core-collapse supernova simulations and neutron stars. These EoS tables are based on a density-dependent relativistic hadron field theory where baryon-baryon interaction is mediated by mesons, using the parameter set DD2 for nucleons. Furthermore, light and heavy nuclei along with interacting nucleons are treated in the nuclear statistical equilibrium model of Hempel and Schaffner-Bielich which includes excluded volume effects. Of all possible hyperons, we consider only the contribution of Λs. We have developed two variants of hyperonic EoS tables: in the npΛφ case the repulsive hyperon-hyperon interaction mediated by the strange φ meson is taken into account, and in the npΛ case it is not. The EoS tables for the two cases encompass a wide range of densities (10{sup –12} to ∼1 fm{sup –3}), temperatures (0.1 to 158.48 MeV), and proton fractions (0.01 to 0.60). The effects of Λ hyperons on thermodynamic quantities such as free energy per baryon, pressure, or entropy per baryon are investigated and found to be significant at higher densities. The cold, β-equilibrated EoS (with the crust included self-consistently) results in a 2.1 M {sub ☉} maximum mass neutron star for the npΛφ case, whereas that for the npΛ case is 1.95 M {sub ☉}. The npΛφ EoS represents the first supernova EoS table involving hyperons that is directly compatible with the recently measured 2 M {sub ☉} neutron stars.

Nucleon electric dipole moments and the isovector parity- and time-reversal-odd pion–nucleon coupling

Directory of Open Access Journals (Sweden)

Chien-Yeah Seng

2014-09-01

Full Text Available The isovector time-reversal- and parity-violating pion–nucleon coupling g¯π(1 is uniquely sensitive to dimension-six interactions between right-handed light quarks and the Standard Model Higgs doublet that naturally arises in left-right symmetric models. Recent work has used the g¯π(1-induced one-loop contribution to the neutron electric dipole moment dn, together with the present experimental dn bound, to constrain the CP-violating parameters of the left-right symmetric model. We show that this and related analyses are based on an earlier meson theory dn computation that is not consistent with the power-counting appropriate for an effective field theory. We repeat the one-loop calculation using heavy baryon chiral perturbation theory and find that the resulting dn sensitivity to g¯π(1 is suppressed, implying more relaxed constraints on the parameter space of the left-right symmetric model. Assuming no cancellations between this loop contribution and other contributions, such as the leading order EDM low-energy constant, the present limit on dn implies |g¯π(1|≲1.1×10−10.

Covariant meson-baryon scattering with chiral and large Nc constraints

International Nuclear Information System (INIS)

Lutz, M.F.M.; Kolomeitsev, E.E.

2001-05-01

We give a review of recent progress on the application of the relativistic chiral SU(3) Lagrangian to meson-baryon scattering. It is shown that a combined chiral and 1/N c expansion of the Bethe-Salpeter interaction kernel leads to a good description of the kaon-nucleon, antikaon-nucleon and pion-nucleon scattering data typically up to laboratory momenta of p lab ≅ 500 MeV. We solve the covariant coupled channel Bethe-Salpeter equation with the interaction kernel truncated to chiral order Q 3 where we include only those terms which are leading in the large N c limit of QCD. (orig.)

Meson-meson bound state in a 2+1 lattice QCD model with two flavors and strong coupling

International Nuclear Information System (INIS)

Faria da Veiga, Paulo A.; O'Carroll, Michael; Neto, Antonio Francisco

2005-01-01

We consider the existence of bound states of two mesons in an imaginary-time formulation of lattice QCD. We analyze an SU(3) theory with two flavors in 2+1 dimensions and two-dimensional spin matrices. For a small hopping parameter and a sufficiently large glueball mass, as a preliminary, we show the existence of isoscalar and isovector mesonlike particles that have isolated dispersion curves (upper gap up to near the two-particle threshold ∼-4lnκ). The corresponding meson masses are equal up to and including O(κ 3 ) and are asymptotically of order -2lnκ-κ 2 . Considering the zero total isospin sector, we show that there is a meson-meson bound state solution to the Bethe-Salpeter equation in a ladder approximation, below the two-meson threshold, and with binding energy of order bκ 2 ≅0.02359κ 2 . In the context of the strong coupling expansion in κ, we show that there are two sources of meson-meson attraction. One comes from a quark-antiquark exchange. This is not a meson exchange, as the spin indices are not those of the meson particle, and we refer to this as a quasimeson exchange. The other arises from gauge field correlations of four overlapping bonds, two positively oriented and two of opposite orientation. Although the exchange part gives rise to a space range-one attractive potential, the main mechanism for the formation of the bound state comes from the gauge contribution. In our lattice Bethe-Salpeter equation approach, this mechanism is manifested by an attractive distance-zero energy-dependent potential. We recall that no bound state appeared in the one-flavor case, where the repulsive effect of Pauli exclusion is stronger

Sensitivity to properties of the phi-meson in the nucleon structure in the chiral soliton model

Energy Technology Data Exchange (ETDEWEB)

Mukhopadhyay, N.C.; Zhang, L. [Rensselaer Polytechnic Inst., Troy, NY (United States)

1994-04-01

The influence of the {phi}-meson on the nucleon properties in the chiral soliton model is discussed. Properties of the {phi}-meson and its photo- and electroproduction are of fundamental interest to CEBAF and its possible future extension. The quark model assigns {phi} an s{bar s} structure, thus forbidding the radiative decay {phi}{yields}{pi}{sup 0}{gamma}. Experimentally it is also found to be suppressed, yielding a branching fraction of 1.3{times}10{sup {minus}3}. However, {phi}{yields}{rho}{pi} and {phi}{yields}{pi}{sup +}{pi}{sup {minus}}{pi}{sup 0} are not suppressed at all. Thus, it is possible to incorporate the widths of these decays into the framework of the chiral soliton model, by making use of a specific model for the compliance with OZI rule. Such a model is for example, the {omega}-{phi} mixing model. Consequence of this in the context of a chiral soliton model, which builds on the {pi}{rho}{omega}a{sub 1}(f{sub 1}) meson effective Lagrangian, is the context of this report.

Covariant density functional theory: The role of the pion

International Nuclear Information System (INIS)

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

2009-01-01

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

Model dependence of isospin sensitive observables at high densities

Energy Technology Data Exchange (ETDEWEB)

Guo, Wen-Mei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); School of Science, Huzhou Teachers College, Huzhou 313000 (China); Yong, Gao-Chan, E-mail: yonggaochan@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, Yongjia [School of Science, Huzhou Teachers College, Huzhou 313000 (China); School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Li, Qingfeng [School of Science, Huzhou Teachers College, Huzhou 313000 (China); Zhang, Hongfei [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Zuo, Wei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2013-10-07

Within two different frameworks of isospin-dependent transport model, i.e., Boltzmann–Uehling–Uhlenbeck (IBUU04) and Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport models, sensitive probes of nuclear symmetry energy are simulated and compared. It is shown that neutron to proton ratio of free nucleons, π{sup −}/π{sup +} ratio as well as isospin-sensitive transverse and elliptic flows given by the two transport models with their “best settings”, all have obvious differences. Discrepancy of numerical value of isospin-sensitive n/p ratio of free nucleon from the two models mainly originates from different symmetry potentials used and discrepancies of numerical value of charged π{sup −}/π{sup +} ratio and isospin-sensitive flows mainly originate from different isospin-dependent nucleon–nucleon cross sections. These demonstrations call for more detailed studies on the model inputs (i.e., the density- and momentum-dependent symmetry potential and the isospin-dependent nucleon–nucleon cross section in medium) of isospin-dependent transport model used. The studies of model dependence of isospin sensitive observables can help nuclear physicists to pin down the density dependence of nuclear symmetry energy through comparison between experiments and theoretical simulations scientifically.

The coupling of heavy mesons to the pion on the lattice; Couplage des mesons lourds au pion sur reseau

Energy Technology Data Exchange (ETDEWEB)

Herdoiza, G

2004-04-15

The QCD non-perturbative effects are among the main sources of uncertainty in our present knowledge of the Standard Model phenomenology. I will present some of the methods which can be used to study these effects, and I will particularly treat the case of lattice QCD. Effective theories can be combined to the lattice approach in order to study the chiral and the heavy quark sectors. I will give some examples of how these properties can be successfully applied to the quark flavour phenomenology. The coupling of heavy mesons to the pion is related to a non-perturbative quantity, noted g-bar, which is required to extract physical results from the effective theory combining both chiral and heavy quark symmetry. This coupling is also involved in the study of the form factors appearing in the heavy to light semi-leptonic decays. These heavy meson decays are used to extract some of the CKM matrix elements which are know, up to now, only with large uncertainties. Moreover, the chiral effects of heavy mesons depend on pion loops whose vertices are precisely the coupling g-bar. These are some of the reasons why the theoretical and experimental determination of this coupling is required. I will present the results of its studies on the lattice and I will compare them to those obtained through several other methods. I will therefore describe these different approaches, their limitations and possible improvements, both from the point of view of the method and of its application to the determination of the coupling g-bar. (author)

The coupling of heavy mesons to the pion on the lattice

International Nuclear Information System (INIS)

Herdoiza, G.

2004-04-01

The QCD non-perturbative effects are among the main sources of uncertainty in our present knowledge of the Standard Model phenomenology. I will present some of the methods which can be used to study these effects, and I will particularly treat the case of lattice QCD. Effective theories can be combined to the lattice approach in order to study the chiral and the heavy quark sectors. I will give some examples of how these properties can be successfully applied to the quark flavour phenomenology. The coupling of heavy mesons to the pion is related to a non-perturbative quantity, noted g-bar, which is required to extract physical results from the effective theory combining both chiral and heavy quark symmetry. This coupling is also involved in the study of the form factors appearing in the heavy to light semi-leptonic decays. These heavy meson decays are used to extract some of the CKM matrix elements which are know, up to now, only with large uncertainties. Moreover, the chiral effects of heavy mesons depend on pion loops whose vertices are precisely the coupling g-bar. These are some of the reasons why the theoretical and experimental determination of this coupling is required. I will present the results of its studies on the lattice and I will compare them to those obtained through several other methods. I will therefore describe these different approaches, their limitations and possible improvements, both from the point of view of the method and of its application to the determination of the coupling g-bar. (author)

Hyperon-nucleon interaction in the quark cluster model

International Nuclear Information System (INIS)

Straub, U.; Zhang Zongye; Braeuer, K.; Faessler, A.; Khadkikar, S.B.; Luebeck, G.

1988-01-01

The lambda-nucleon and sigma-nucleon interaction is described in the nonrelativistic quark cluster model. The SU(3) flavor symmetry breaking due to the different quark masses is taken into account, i.e. different wavefunctions for the light (up, down) and heavy (strange) quarks are used in flavor and orbital space. The six-quark wavefunction is fully antisymmetrized. The model hamiltonian contains gluon exchange, pseudoscalar meson exchange and a phenomenological σ-meson exchange. The six-quark scattering problem is solved within the resonating group method. The experimental lambda-nucleon and sigma-nucleon cross sections are well reproduced. (orig.)

THE PROPERTIES OF THE (K)over-bar* MESON IN DENSE MATTER

NARCIS (Netherlands)

Molina, R.; Tolos, L.; Oset, E.; Ramos, A.

2011-01-01

In this talk were view the properties of (K) over bar* mesons in nuclear matter. A unitary approach in coupled channels within the framework of the local hidden gauge formalism is used to account for the interaction of the antikaon with the nucleons and the (K) over bar pi decay channel is

Asymptotic energy scale factors for pseudoscalar meson scattering and charmed meson couplings

International Nuclear Information System (INIS)

Thews, R.L.

1977-01-01

Energy scale factors ν 0 for PP → PP scattering amplitudes are related via absence of exotic resonances of ratios of tensor to vector coupling strengths. These same ratios are extracted from FESR's for non-exotic reactions. The scale factors obtained are all of the order of 1.0 GeV 2 or less, indepedent of quantum numbers. This contradicts the expectations of dual amplitudes in which ν 0 =1/α', and trajectory slopes are smaller for charmed mesons. Decay widths for tensor mesons are predicted. An observed SU(3) violation for the ratio A 2 → KantiK/K** → Kπ is shown to be consistent with the FESR results. Charmed meson decays are predicted to be factors of 2 to 3 larger than those predicted by SU(4). (author)

Coupled-channel analysis of nucleon scattering from 40Ca

International Nuclear Information System (INIS)

Delaroche, J.P.; Honore, G.M.; Tornow, W.; Walter, R.L.

1985-05-01

Differential cross sections and analyzing powers for neutron scattering from 40 Ca have been measured at TUNL in the 10-17 MeV energy range. These measurements and other σ(theta) and σsub(T) measurements, as well as available 40 Ca+p data, have been combined together in a coupled-channel analysis in order to trace the properties (energy dependencies, spin-orbit potentials, deformation parameters) of the nucleon + 40 Ca potential up to 80 MeV

Coupled-channel analysis of nucleon scattering from 40Ca

International Nuclear Information System (INIS)

Delaroche, J.-P.; Honore, G.M.; Tornow, W.; Walter, R.L.

1986-01-01

Differential cross sections and analyzing powers for neutron scattering from 40 Ca have been measured at TUNL in the 10-17 MeV energy range. These measurements and other σ(theta) and σsub(T) measurements, as well as available 40 Ca+p data, have been combined together in a coupled-channel analysis in order to trace the properties (energy dependencies, spin-orbit potentials, deformation parameters) of the nucleon + 40 Ca potential up to 80 MeV. (author)

Composite mesons in self-confining chiral solitons

International Nuclear Information System (INIS)

Tandy, P.C.; Frank, M.R.

1991-01-01

Most quark-meson models for formation of a baryon as a bag or soliton solution begin with elementary local meson fields including a classical scalar configuration that provides repulsion of valence quarks from the vacuum. This presentation explores aspects of the very different formation mechanism that operates in a model where chiral effective meson fields are composite objects generated from bilocal qq-bar fluctuation fields and the dynamical quark mass can be self-confining. The focus is on the dynamical self-energy for quarks and the related distributed vertex for quark meson coupling. Initial numerical work to explore the practical consequences of these features is presented in the context of a static mean-field soliton. The particular method employed to identify the energy functional at the mean field or Hartree level is to obtain the standard effective action from the Legendre transformation with the help of a chemical potential constraint for the baryon number. The purpose of this approach is two-fold. First, a possible future consideration of radiative corrections might be undertaken by systematically continuing with the loop expansion beyond the lowest level. A second, more practical reason, is that in the presence of a general space-time dependent dynamical self-energy for quarks there are wavefunction renormalisation effects and energy self-consistencies to be defined and maintained for the valence quark states and eigenvalues. Speculations are made on whether this point of view can motivate meson-nucleon relativistic field models containing intrinsic cutoffs for use in nuclear physics. 29 refs., 5 figs

Properties of vector and axial-vector mesons from a generalized Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Bernard, V.; Meissner, U.G.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge

1988-01-01

We construct a generalized Nambu-Jona-Lasinio lagrangian including scalar, pseudoscalar, vector and axial-vector mesons. We specialize to the two-flavor case. The properties of the structured vacuum as well as meson masses and coupling constants are calculated giving an overall agreement within 20% of the experimental data. We investigate the meson properties at finite density. In contrast to the mass of the scalar σ-meson, which decreases sharply with increasing density, the vector meson masses are almost independent of density. Furthermore, the vector-meson-quark coupling constants are also stable against density changes. We point out that these results imply a softening of the nuclear equation of state at high densities. Furthermore, we discuss the breakdown of the KFSR relation on the quark level as well as other deviations from phenomenological concepts such as universality and vector meson dominance. (orig.)

Nucleon electric dipole moments and the isovector parity- and time-reversal-odd pion–nucleon coupling

Energy Technology Data Exchange (ETDEWEB)

Seng, Chien-Yeah [Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts Amherst, Amherst, MA 01003 (United States); Vries, Jordy de [Institute for Advanced Simulation, Institut für Kernphysik, and Jülich Center for Hadron Physics, Forschungszentrum Jülich, D-52425 Jülich (Germany); Mereghetti, Emanuele [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Patel, Hiren H. [Particle and Astro-Particle Physics Division, Max-Planck Institute for Nuclear Physics (MPIK), Saupfercheckweg 1, 69117 Heidelberg (Germany); Ramsey-Musolf, Michael [Amherst Center for Fundamental Interactions, Department of Physics, University of Massachusetts Amherst, Amherst, MA 01003 (United States); Kellogg Radiation Laboratory, California Institute of Technology Pasadena, CA 91125 (United States)

2014-09-07

The isovector time-reversal- and parity-violating pion–nucleon coupling g{sup ¯}{sub π}{sup (1)} is uniquely sensitive to dimension-six interactions between right-handed light quarks and the Standard Model Higgs doublet that naturally arises in left-right symmetric models. Recent work has used the g{sup ¯}{sub π}{sup (1)}-induced one-loop contribution to the neutron electric dipole moment d{sub n}, together with the present experimental d{sub n} bound, to constrain the CP-violating parameters of the left-right symmetric model. We show that this and related analyses are based on an earlier meson theory d{sub n} computation that is not consistent with the power-counting appropriate for an effective field theory. We repeat the one-loop calculation using heavy baryon chiral perturbation theory and find that the resulting d{sub n} sensitivity to g{sup ¯}{sub π}{sup (1)} is suppressed, implying more relaxed constraints on the parameter space of the left-right symmetric model. Assuming no cancellations between this loop contribution and other contributions, such as the leading order EDM low-energy constant, the present limit on d{sub n} implies |g{sup ¯}{sub π}{sup (1)}|≲1.1×10{sup −10}.

Relationship between the symmetry energy and the single-nucleon potential in isospin-asymmetric nucleonic matter

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.)

Relationship between the symmetry energy and the single-nucleon potential in isospin-asymmetric nucleonic matter

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.)

Sigma-omega meson coupling and properties of nuclei and nuclear matter

International Nuclear Information System (INIS)

Haidari, Maryam M.; Sharma, Madan M.

2008-01-01

We have constructed a Lagrangian model with a coupling of σ and ω mesons in the relativistic mean-field theory. Properties of finite nuclei and nuclear matter are explored with the new Lagrangian model SIG-OM. The study shows that an excellent description of binding energies and charge radii of nuclei over a large range of isospin is achieved with SIG-OM. With an incompressibility of nuclear matter K=265 MeV, it is also able to describe the breathing-mode isoscalar giant monopole resonance energies appropriately. It is shown that the high-density behaviour of the equation of state of nuclear and neutron matter with the σ-ω coupling is much softer than that of the non-linear scalar coupling model

Final State Interaction on non Mesonic Hyperon Weak Decay Spectra of Λ12C

International Nuclear Information System (INIS)

Gonzalez, I.; Rodriguez, O.; Deppman, A.; Duarte, S.; Krmpotic, F.

2011-01-01

In the present work, we study the one nucleon induced non mesonic hyperon weak decay (NMWD)(ΛΝ → ηΝ) on the Λ 12 C hypernuclei with corresponding transition rates given by Γ ρ ≡ Γ (Λρ → ηρ) and Γ η ≡ Γ (Λη → ηη) respectively. The whole nuclear process is described by using a connection of two models, one to describe the primary non mesonic weak decay in the nuclear environment and another one to follows the time evolution of the outgoing of nucleons from nuclear system, to consider the Final State Interaction (FSI). The Independent-Particle Shell-Model (IPSM) is used to depict the dynamic of the primary decay by mean of the exchange of π and + Κ mesons with usual parameterization. A time dependent multicolisional intranuclear cascade approach implemented on the CRISP (Collaboration Rio-Sao Paulo) code incorporates the FSI to the Γ η /Γ ρ ratio calculation and the behaviour of these value with the coulomb barrier as well as to the observable nucleon kinetic energy spectra and also to angular correlation determinations. Recent KEK and FINUDA experiments on one- and two-nucleon non mesonic weak decay (NMWD) spectra in Λ 12 C hypernuclei are analyzed theoretically and the effect of FSI is determined within our model scenery. (Author)

Meson exchange currents in a relativistic model for electromagnetic one nucleon emission

International Nuclear Information System (INIS)

Meucci, Andrea; Giusti, Carlotta; Pacati, Franco Davide

2002-01-01

We analyze the role of meson exchange currents (MECs) in photon- and electron-induced one nucleon emission reactions in a fully relativistic model. The relativistic mean-field theory is used for the bound state and the Pauli reduction for the scattering state. Direct one-body and exchange two-body terms in the nuclear current are considered. Results for the 12 C(γ,p) and 16 O(γ,p) differential cross sections and photon asymmetries are displayed in an energy range between 60 and 196 MeV. The two-body seagull current affects the cross section less than in nonrelativistic analyses. In the case of the 16 O(γ,n) differential cross section, MEC effects are large but not sufficient to reproduce the data. MECs have a small effect on (e,e ' p) calculations

Superheavy Nuclei in the Quark-Meson-Coupling Model

Directory of Open Access Journals (Sweden)

Stone Jirina

2017-01-01

Full Text Available We present a selection of the first results obtained in a comprehensive calculation of ground state properties of even-even superheavy nuclei in the region of 96 < Z < 136 and 118 < N < 320 from the Quark-Meson-Coupling model (QMC. Ground state binding energies, the neutron and proton number dependence of quadrupole deformations and Qα values are reported for even-even nuclei with 100 < Z < 136 and compared with available experimental data and predictions of macro-microscopic models. Predictions of properties of nuclei, including Qα values, relevant for planning future experiments are presented.

In-medium pseudoscalar D/B mesons and charmonium decay width

Energy Technology Data Exchange (ETDEWEB)

Chhabra, Rahul; Kumar, Arvind [Dr. B.R. Ambedkar National Institute of Technology Jalandhar, Department of Physics, Jalandhar, Punjab (India)

2017-05-15

Using QCD sum rules and the chiral SU(3) model, we investigate the effect of temperature, density, strangeness fraction and isospin asymmetric parameter on the shift in masses and decay constants of the pseudoscalar D and B meson in the hadronic medium, which consist of nucleons and hyperons. The in-medium properties of D and B mesons within the QCD sum rule approach depend upon the quark and gluon condensates. In the chiral SU(3) model, quark and gluon condensates are introduced through the explicit symmetry breaking term and the trace anomaly property of the QCD, respectively and are written in terms of the scalar fields σ, ζ, δ and χ. Hence, through medium modification of σ, ζ, δ and χ fields, we obtain the medium-modified masses and decay constants of D and B mesons. As an application, using {sup 3}P{sub 0} model, we calculate the in-medium decay width of the higher charmonium states ψ(3686), ψ(3770) and χ(3556) to the D anti D pairs, considering the in-medium mass of D mesons. These results may be important to understand the possible outcomes of the high-energy physics experiments, e.g., CBM and PANDA at GSI, Germany. (orig.)

In-medium pseudoscalar D/B mesons and charmonium decay width

Science.gov (United States)

Chhabra, Rahul; Kumar, Arvind

2017-05-01

Using QCD sum rules and the chiral SU(3) model, we investigate the effect of temperature, density, strangeness fraction and isospin asymmetric parameter on the shift in masses and decay constants of the pseudoscalar D and B meson in the hadronic medium, which consist of nucleons and hyperons. The in-medium properties of D and B mesons within the QCD sum rule approach depend upon the quark and gluon condensates. In the chiral SU(3) model, quark and gluon condensates are introduced through the explicit symmetry breaking term and the trace anomaly property of the QCD, respectively and are written in terms of the scalar fields σ, ζ, δ and χ. Hence, through medium modification of σ, ζ, δ and χ fields, we obtain the medium-modified masses and decay constants of D and B mesons. As an application, using {}3P0 model, we calculate the in-medium decay width of the higher charmonium states ψ(3686), ψ(3770) and χ(3556) to the D\\bar{D} pairs, considering the in-medium mass of D mesons. These results may be important to understand the possible outcomes of the high-energy physics experiments, e.g., CBM and PANDA at GSI, Germany.

Measurement of the gluon spin inside the nucleon through the muon-production of charmed mesons in COMPASS

International Nuclear Information System (INIS)

Robinet, F.

2008-09-01

The 1/2 spin of the nucleon decomposes into 3 contributions: the quark and the gluon spin and their angular momenta. It is known that the fraction of the nucleon spin carried by the quark is small. Nowadays, a series of measurements aims to determine the contribution of the gluon spin in order, perhaps, to recover the totality of the nucleon spin. This is one of the main goals of the COMPASS experiment at CERN where spin asymmetries are measured using a polarized muon beam on a polarized nucleon target. The photon-gluon fusion processes, sensitive to the gluon polarization, are selected by detecting D 0 in the final state. This method offers a very clean selection of the desired signal but is statistically limited. The work presented in this thesis is primarily focused on the development of an analysis method maximizing the statistics. In particular, the D 0 mesons reconstruction is submitted to a high combinatorial background. Parameterizing the probability for an event to signal the statistical error is significantly reduced. The momentum resolution, associated with the particle detection, is an important factor allowing to minimize the combinatorial background. This thesis presents the characteristics of drift chamber-type detectors contributing to the performances of the COMPASS spectrometer. Finally, the results joined by the systematic errors study, are presented along with their implications on the contribution of the gluon spin to the nucleon spin. (author)

$\\phi$-meson production at forward rapidity in p-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV and in pp collisions at $\\sqrt{s}$ = 2.76 TeV

CERN Document Server

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

2017-05-10

The first measurement of $\\phi$-meson production in p-Pb collisions at a nucleon-nucleon centre-of-mass energy $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV has been performed with the ALICE apparatus at the LHC. $\\phi$ mesons have been identified in the dimuon decay channel in the transverse momentum ($p_{\\rm T}$) range $1 < p_{\\rm T} < 7$ GeV/c, both in the p-going ($2.03 < y < 3.53$) and the Pb-going ($-4.46 < y < -2.96$) directions, where $y$ stands for the rapidity in the nucleon-nucleon centre-of-mass. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward-backward asymmetry for $\\phi$-meson production is measured for $2.96 < |y| < 3.53$, showing no significant $p_{\\rm T}$ dependence within the uncertainties. The $p_{\\rm T}$-dependence of the $\\phi$ nuclear modification factor $R_{\\rm pPb}$ exhibits an enhancement up to a factor 1.6 at $p_{\\rm T}$ = 3-4 GeV/c in the Pb-going direction. The $p_{\\rm T}$ dependence of the $\\phi$-meson cross section...

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

Coherent generation of mesons in nucleon-nucleon interactions

CERN Document Server

Takibaev, Z S; Zaitsev, K G

1974-01-01

The authors have at an experiment conducted at CERN searched for events of 0 four-prong type which satisfy coherent pion production. The 2-meter hydrogen bubble chamber at CERN was bombarded by 19.07 GeV protons. The cross-section for four final state particle events was 13.04 mb. the cross-section for the process pp to pp pi /sup +/ pi /sup -/ was 1.1 mb and the cross section for coherent pion production was found to vary according to the criteria used between 0.044 mb. and 0.2 mb. Some theoretical work is given using the Glauber formalism in which it is assumed that the nucleon behaves like a nucleus and contains sub-particles. From the theory and data an upper limit of 10 is put on the number of subparticles in the nucleon. (9 refs).

Examination of the strangeness contribution to the nucleon magnetic moment

NARCIS (Netherlands)

Chen, XS; Timmermans, RGE; Sun, WM; Zong, HS; Wang, F

We examine the nucleon strangeness magnetic moment mu(s) with a lowest order meson cloud model. We observe that (1) strangeness in the nucleon is a natural requirement of the empirical relation mu(p)/mu(n)similar or equal to-3/2, which favors an SU(3) octet meson cloud instead of merely the SU(2)

Coupled-channel analysis of nucleon scattering from /sup 40/Ca

Energy Technology Data Exchange (ETDEWEB)

Delaroche, J.-P.; Honore, G.M.; Tornow, W.; Walter, R.L.

1986-01-01

Differential cross sections and analyzing powers for neutron scattering from /sup 40/Ca have been measured at TUNL in the 10-17 MeV energy range. These measurements and other sigma(theta) and sigmasub(T) measurements, as well as available /sup 40/Ca+p data, have been combined together in a coupled-channel analysis in order to trace the properties (energy dependencies, spin-orbit potentials, deformation parameters) of the nucleon + /sup 40/Ca potential up to 80 MeV.

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

International Nuclear Information System (INIS)

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

2005-01-01

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

Pseudoscalar meson photoproduction: from known to undiscovered resonances

International Nuclear Information System (INIS)

Saghai, B.; Tabakin, F.

1996-01-01

The role of dynamics in spin observables for pseudoscalar meson photoproduction is investigated using a density matrix approach in a multipole truncated framework. Extraction of novel rules for γp → π + n, K + Λ and ηp reactions based on resonance dominance, and on other broad and reasonable dynamical assumptions, are discussed. Observables that are particularly sensitive to missing nucleonic resonances predicted by quark-based approaches, are singled out. (authors)

New QCD sum rules for nucleon axial-vector coupling constants

International Nuclear Information System (INIS)

Lee, F.X.; Leinweber, D.B.; Jin, X.

1997-01-01

Two new sets of QCD sum rules for the nucleon axial-vector coupling constants are derived using the external-field technique and generalized interpolating fields. An in-depth study of the predicative ability of these sum rules is carried out using a Monte Carlo based uncertainty analysis. The results show that the standard implementation of the QCD sum rule method has only marginal predicative power for the nucleon axial-vector coupling constants, as the relative errors are large. The errors range from approximately 50% to 100% compared to the nucleon mass obtained from the same method, which has only a 10%- 25% error. The origin of the large errors is examined. Previous analyses of these coupling constants are based on sum rules that have poor operator product expansion convergence and large continuum contributions. Preferred sum rules are identified and their predictions are obtained. We also investigate the new sum rules with an alternative treatment of the problematic transitions which are not exponentially suppressed in the standard treatment. The alternative treatment provides exponential suppression of their contributions relative to the ground state. Implications for other nucleon current matrix elements are also discussed. copyright 1997 The American Physical Society

Central depression in nucleonic densities: Trend analysis in the nuclear density functional theory approach

Science.gov (United States)

Schuetrumpf, B.; Nazarewicz, W.; Reinhard, P.-G.

2017-08-01

Background: The central depression of nucleonic density, i.e., a reduction of density in the nuclear interior, has been attributed to many factors. For instance, bubble structures in superheavy nuclei are believed to be due to the electrostatic repulsion. In light nuclei, the mechanism behind the density reduction in the interior has been discussed in terms of shell effects associated with occupations of s orbits. Purpose: The main objective of this work is to reveal mechanisms behind the formation of central depression in nucleonic densities in light and heavy nuclei. To this end, we introduce several measures of the internal nucleonic density. Through the statistical analysis, we study the information content of these measures with respect to nuclear matter properties. Method: We apply nuclear density functional theory with Skyrme functionals. Using the statistical tools of linear least square regression, we inspect correlations between various measures of central depression and model parameters, including nuclear matter properties. We study bivariate correlations with selected quantities as well as multiple correlations with groups of parameters. Detailed correlation analysis is carried out for 34Si for which a bubble structure has been reported recently, 48Ca, and N =82 , 126, and 184 isotonic chains. Results: We show that the central depression in medium-mass nuclei is very sensitive to shell effects, whereas for superheavy systems it is firmly driven by the electrostatic repulsion. An appreciable semibubble structure in proton density is predicted for 294Og, which is currently the heaviest nucleus known experimentally. Conclusion: Our correlation analysis reveals that the central density indicators in nuclei below 208Pb carry little information on parameters of nuclear matter; they are predominantly driven by shell structure. On the other hand, in the superheavy nuclei there exists a clear relationship between the central nucleonic density and symmetry energy.

Latest results from meson photoproduction at ELSA and MAMI

Science.gov (United States)

Krusche, B.

2014-06-01

Photoproduction of mesons plays a key role for the investigation of the excitation spectrum of the nucleon and thus for our understanding of the strong interaction in the non-perturbative regime. In this contribution we discuss recent results from the experiments at the tagged photon beams of the electron accelerators ELSA in Bonn and MAMI in Mainz. They include the measurement of cross sections and (double) polarization observables for single meson production and production of meson pairs off free protons as well as of quasi-free nucleons bound in light nuclei (in particular the deuteron).

Charge dependence and charge asymmetry in the nucleon-nucleon interaction due to processes involving Δ's

International Nuclear Information System (INIS)

Wells, T.B.

1978-01-01

The charge dependence and charge asymmetry of the nucleon-nucleon force arising from the exchange of a pion and a photon with the excitation of a nucleon resonance [Δ(1236)] is calculated. This charge dependence and asymmetry is studied through its effects on the 1 S nucleon-nucleon scattering lengths. The complexity of the calculation forces the use of approximations. The calculation is performed first with a pole approximation for the resonance and a second time with a Chew-Low description of the resonance. Both calculations neglect nuclear recoil. Estimates of this effect are made. The changes in the scattering lengths are small ( +- / 2 = 1.0225 G/sub π 0 / 2 will explain the proton-neutron scattering length

Collective flows of protons and $\\pi^-$ mesons in $^{2}$H + C, Ta and He plus C, Ta collisions at 3.4 GeV/nucleon

CERN Document Server

Chkhaidze, L; Djobava, T; Kladnitskaya, E; Kharkhelauri, L; Uzhinsky, V

2011-01-01

Collective flows of protons and negative pions have been studied in (2)H + C, Ta and He + C, Ta collisions at an energy of 3.4 GeV/nucleon. The data have been obtained by the 2-m Propane Bubble Chamber (PBC-500) at JINR. It is found that the directed flow of protons and pi(-) mesons characterized by d /d(y) increases with increase of the mass numbers of colliding nucleus pairs; the elliptic proton flow points out of the reaction plane and also strengthens as the system mass increases; the negative pion directed flow is in the same reaction plane as the proton flow for the lighter (2H + C, He + C) systems and in the opposite direction for the heavier ((2)H + Ta, He + Ta) systems. In (2)H + C, He + C, C + C, C + Ne, (2)H + Ta, He + Ta, C + Cu, and C + Ta collisions, the linear dependence of directed and elliptic flow parameters from mass numbers of projectile and target nuclei, (A(P).A(T))(1/2), is similar for protons while for pi(-) mesons the dependence of directed flow parameters is stronger. The ultrarelati...

Quark-diquark approximation of the three-quark structure of a nucleon and the NN phase shifts

International Nuclear Information System (INIS)

Efimov, G.V.; Ivanov, M.A.

1988-01-01

The quark-diquark approximations of the three-quark structure of a nucleon are considered in the framework of the quark confinement model (QCM) based on definite concepts of the hadronization and quark confinement. The static nucleon characteristics (magnetic moments, ratio G A /G V and strong meson-nucleon coupling constants) are calculated. The behaviour of the electromagnetic and strong nucleon form factors is obtained at the low energy (0≤0 2 =-q 2 2 , where q is a transfer momentum). The one-boson exchange potential is constructed and the NN-phase-shifts are computed. Our results are compared with experiment and the Bonn potential model. 45 refs.; 7 figs.; 3 tabs

Global fits of the dark matter-nucleon effective interactions

International Nuclear Information System (INIS)

Catena, Riccardo; Gondolo, Paolo

2014-01-01

The effective theory of isoscalar dark matter-nucleon interactions mediated by heavy spin-one or spin-zero particles depends on 10 coupling constants besides the dark matter particle mass. Here we compare this 11-dimensional effective theory to current observations in a comprehensive statistical analysis of several direct detection experiments, including the recent LUX, SuperCDMS and CDMSlite results. From a multidimensional scan with about 3 million likelihood evaluations, we extract the marginalized posterior probability density functions (a Bayesian approach) and the profile likelihoods (a frequentist approach), as well as the associated credible regions and confidence levels, for each coupling constant vs dark matter mass and for each pair of coupling constants. We compare the Bayesian and frequentist approach in the light of the currently limited amount of data. We find that current direct detection data contain sufficient information to simultaneously constrain not only the familiar spin-independent and spin-dependent interactions, but also the remaining velocity and momentum dependent couplings predicted by the dark matter-nucleon effective theory. For current experiments associated with a null result, we find strong correlations between some pairs of coupling constants. For experiments that claim a signal (i.e., CoGeNT and DAMA), we find that pairs of coupling constants produce degenerate results

Coupled-channel analysis of nucleon scattering from /sup 40/Ca

International Nuclear Information System (INIS)

Delaroche, J.P.; Honore, G.M.; Tornow, W.; Walter, R.L.

1985-01-01

Differential cross sections and analyzing powers for neutron scattering from /sup 40/Ca have been measured at TUNL in the 10-17 MeV energy range. These measurements and other σ(θ) and σ/sub T/ measurements, as well as available /sup 40/Ca+p data, have been combined together in a coupled-channel analysis in order to trace the properties (energy dependencies, spin-orbit potentials, deformation parameters) of the nucleon + /sup 40/Ca potential up to 80 MeV

Static and Covariant Meson-Exchange Interactions in Nuclear Matter

International Nuclear Information System (INIS)

Carlson, B.V.; Hirata, D.

2011-01-01

The Dirac version of static meson exchange interactions provides a good description of low-energy NN scattering as well as very reasonable saturation properties in Dirac-Brueckner calculations of nuclear matter. We include retardation terms to make these interactions covariant and readjust the coupling constants so as to maintain a reasonable description of NN scattering. In this case, we find the Dirac-Brueckner approximation to nuclear matter to be extremely overbound. The Bonn meson-exchange interactions provide a good fit to low-energy nucleon-nucleon scattering and the deuteron binding energy using a static interaction and the Thompson form of the reduced two-nucleon interaction. We have readjusted the coupling constants of the these interactions to obtain almost equivalent fits to the scattering data and deuteron binding energy with a static interaction and the Blankenbecler-Sugar form of the reduced two-nucleon propagator and using both forms of the propagator with a covariant interaction. Dirac-Brueckner calculations using the static interactions furnish saturation properties similar to those found for the Bonn interactions. The covariant interactions, on the contrary, yield extreme overbinding and do not show signs of saturation before our calculations diverge. One of the advantages claimed for Dirac mean field calculations over nonrelativistic ones has been the fact that they yield reasonable saturation properties without the necessity of a three-body interaction. This is usually credited to the three-body effects introduced by virtual scattering through the Dirac sea states. These are included, in part, through the Dirac form of the self-energy in our calculations. However, we have explicitly excluded their contribution to the Brueckner scattering kernel. Dirac-Brueckner calculations in which both the positive and negative energy states are included in the scattering kernel result in less binding than those that include only the positive-energy ones

Theta dependence in holographic QCD

Energy Technology Data Exchange (ETDEWEB)

Bartolini, Lorenzo [Dipartimento di Fisica “E. Fermi' , Università di Pisa and INFN, Sezione di Pisa,Largo B. Pontecorvo 3, I-56127 Pisa (Italy); Bigazzi, Francesco [INFN, Sezione di Firenze,Via G. Sansone 1, I-50019 Sesto Fiorentino (Firenze) (Italy); Bolognesi, Stefano [Dipartimento di Fisica “E. Fermi' , Università di Pisa and INFN, Sezione di Pisa,Largo B. Pontecorvo 3, I-56127 Pisa (Italy); Cotrone, Aldo L. [INFN, Sezione di Firenze,Via G. Sansone 1, I-50019 Sesto Fiorentino (Firenze) (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze,Via G. Sansone 1, I-50019 Sesto Fiorentino (Firenze) (Italy); Manenti, Andrea [Institute of Physics, EPFL,Rte de la Sorge, BSP 728, CH-1015 Lausanne (Switzerland)

2017-02-07

We study the effects of the CP-breaking topological θ-term in the large N{sub c} QCD model by Witten, Sakai and Sugimoto with N{sub f} degenerate light flavors. We first compute the ground state energy density, the topological susceptibility and the masses of the lowest lying mesons, finding agreement with expectations from the QCD chiral effective action. Then, focusing on the N{sub f}=2 case, we consider the baryonic sector and determine, to leading order in the small θ regime, the related holographic instantonic soliton solutions. We find that while the baryon spectrum does not receive O(θ) corrections, this is not the case for observables like the electromagnetic form factor of the nucleons. In particular, it exhibits a dipole term, which turns out to be vector-meson dominated. The resulting neutron electric dipole moment, which is exactly the opposite as that of the proton, is of the same order of magnitude of previous estimates in the literature. Finally, we compute the CP-violating pion-nucleon coupling constant ḡ{sub πNN}, finding that it is zero to leading order in the large N{sub c} limit.

Inclusive vector meson production and hadron structure

International Nuclear Information System (INIS)

Boeckmann, K.

1977-08-01

It is shown that J/PSI production in hadronic interactions is dominated by central production from sea quarks even at beam momenta as low as 40 GeV/c. All known experimental data on inclusive vector meson production support the hypothesis that cross sections obtained from meson-nucleon and nucleon-nucleon interactions have to be compared in the quark C.M. system. With the distinction of sea quark and valence quark interactions in the additive quark model a consistent description of inclusive rho, K*, PHI and J/PSI production in hadronic interactions. A natural connection of inclusive rho 0 production cross sections in anti pp, pp and πp interactions is obtained. (orig.) [de

Density dependence of the nuclear energy-density functional

Science.gov (United States)

Papakonstantinou, Panagiota; Park, Tae-Sun; Lim, Yeunhwan; Hyun, Chang Ho

2018-01-01

Background: The explicit density dependence in the coupling coefficients entering the nonrelativistic nuclear energy-density functional (EDF) is understood to encode effects of three-nucleon forces and dynamical correlations. The necessity for the density-dependent coupling coefficients to assume the form of a preferably small fractional power of the density ρ is empirical and the power is often chosen arbitrarily. Consequently, precision-oriented parametrizations risk overfitting in the regime of saturation and extrapolations in dilute or dense matter may lose predictive power. Purpose: Beginning with the observation that the Fermi momentum kF, i.e., the cubic root of the density, is a key variable in the description of Fermi systems, we first wish to examine if a power hierarchy in a kF expansion can be inferred from the properties of homogeneous matter in a domain of densities, which is relevant for nuclear structure and neutron stars. For subsequent applications we want to determine a functional that is of good quality but not overtrained. Method: For the EDF, we fit systematically polynomial and other functions of ρ1 /3 to existing microscopic, variational calculations of the energy of symmetric and pure neutron matter (pseudodata) and analyze the behavior of the fits. We select a form and a set of parameters, which we found robust, and examine the parameters' naturalness and the quality of resulting extrapolations. Results: A statistical analysis confirms that low-order terms such as ρ1 /3 and ρ2 /3 are the most relevant ones in the nuclear EDF beyond lowest order. It also hints at a different power hierarchy for symmetric vs. pure neutron matter, supporting the need for more than one density-dependent term in nonrelativistic EDFs. The functional we propose easily accommodates known or adopted properties of nuclear matter near saturation. More importantly, upon extrapolation to dilute or asymmetric matter, it reproduces a range of existing microscopic

Pseudoscalar meson photoproduction: from known to undiscovered resonances

Energy Technology Data Exchange (ETDEWEB)

Saghai, B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Tabakin, F.

1996-12-31

The role of dynamics in spin observables for pseudoscalar meson photoproduction is investigated using a density matrix approach in a multipole truncated framework. Extraction of novel rules for {gamma}p {yields} {pi}{sup +}n, K{sup +}{Lambda} and {eta}p reactions based on resonance dominance, and on other broad and reasonable dynamical assumptions, are discussed. Observables that are particularly sensitive to missing nucleonic resonances predicted by quark-based approaches, are singled out. (authors). 25 refs.

Numerical Exact Ab Initio Four-Nucleon Scattering Calculations: from Dream to Reality

Science.gov (United States)

Fonseca, A. C.; Deltuva, A.

2017-03-01

In the present manuscript we review the work of the last ten years on the pursuit to obtain numerical exact solutions of the four-nucleon scattering problem using the most advanced force models that fit two nucleon data up to pion production threshold with a χ ^2 per data point approximately one, together with the Coulomb interaction between protons; three- and four-nucleon forces are also included in the framework of a meson exchange potential model where NN couples to NΔ. Failure to describe the world data on four-nucleon scattering observables in the framework of a non relativistic scattering approach falls necessarily on the force models one uses. Four-nucleon observables pose very clear challenges, particular in the low energy region where there are a number of resonances whose position and width needs to be dynamically generated by the nucleon-nucleon (NN) interactions one uses. In addition, our calculations constitute the most advance piece of work where observables for all four-nucleon reactions involving isospin I=0, I=0 coupled to I=1 and isospin I=1 initial states are calculated at energies both below and above breakup threshold. We also present a very extensive comparison between calculated results and data for cross sections and spin observables. Therefore the present work reveals both the shortcomings and successes of some of the present NN force models in describing four-nucleon data and serve as a benchmark for future developments.

Is nuclear structure relevant to non-mesonic hyper-nuclear weak decay?

International Nuclear Information System (INIS)

Wu, H.C.; Ponce, W.A.

2001-01-01

Full text: The focus of existing studies of the non-mesonic hypernuclear weak decay has been on the two-body process ΛN → NN, whereas the investigation on effects of nuclear structure is relatively rare. Some authors even assumed that the nuclear structure is irrelevant to the non mesonic hypernuclear weak decay. In this work we try to reveal the importance of nuclear structure in non mesonic weak decay of the Λ - hypernuclei through examining the relevance of many-body properties as well as the single particle properties of different nuclear models. For hypernucleus 12 Λ C, a comparison between the L-S coupling (realized by the symmetry model SU(4) x SU(3) and the j-j coupling (realized by the single particle shell model) gives an estimate of the range of nuclear structure effects. It has been found that while the total decay rate is almost independent of coupling schemes, the ratio Γn/Γp has a difference of around 30% between the two limits of many-body wave functions. There also exists a strong dependence of the total decay rate and the ratio Γn/Γp on the single particle properties of shell model, such as the binding energy of nucleon and the parameters of harmonic oscillator orbits, etc. Therefore, one may conclude that the nuclear structure is relevant to the non-mesonic hypernuclear weak decay. With the mechanism of ΛN → NN transition being restricted to one pion exchange (OPE) only, the consequences of possible contribution from the ΔI = 3/2 channel is investigated in a phenomenological manner. It has been shown that a mixing of ΔI = 3/2 channel will change the total decay rate as well as the ratio Γn/Γp considerably. (Author)

Relativistic transport theory for hadronic matter

International Nuclear Information System (INIS)

Shun-Jin Wang; Bao-An Li; Bauer, W.; Randrup, J.

1991-01-01

We derive coupled equations of motion for the density matrices for nucleons, Δ resonances, and π mesons, as well as for the pion--baryon interaction vertex function for the description of nuclear reactions at intermediate energies. We start from an effective hadronic Lagrangian density with minimal coupling between baryons and mesons. By truncating at the level of three-body correlations and using the G-matrix method to solve the equations of motion for the two-body correlation functions, a closed equation of motion for the one-body density matrices is obtained. A subsequent Wigner transformation then leads to a tractable set of relativistic transport equations for interacting nucleons, deltas, and pions. copyright 1991 Academic Press, Inc

Pseudoscalar meson decay constants and couplings, the Witten-Veneziano formula beyond large Nc, and the topological susceptibility

International Nuclear Information System (INIS)

Shore, G.M. . E-mail g.m.shore@swansea.ac.uk

2006-01-01

The QCD formulae for the radiative decays η,η ' ->γγ, and the corresponding Dashen-Gell-Mann-Oakes-Renner relations, differ from conventional PCAC results due to the gluonic U(1) A axial anomaly. This introduces a critical dependence on the gluon topological susceptibility. In this paper, we revisit our earlier theoretical analysis of radiative pseudoscalar decays and the DGMOR relations and extract explicit experimental values for the decay constants. This is our main result. The flavour singlet DGMOR relation is the generalisation of the Witten-Veneziano formula beyond large N c , so we are able to give a quantitative assessment of the realisation of the 1/N c expansion in the U(1) A sector of QCD. Applications to other aspects of η ' physics, including the relation with the first moment sum rule for the polarised photon structure function g 1 γ , are highlighted. The U(1) A Goldberger-Treiman relation is extended to accommodate SU(3) flavour breaking and the implications of a more precise measurement of the η and η ' -nucleon couplings are discussed. A comparison with the existing literature on pseudoscalar meson decay constants using large-N c chiral Lagrangians is also made

The nucleon-nucleon correlations and the integral characteristics of the potential distributions in 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

Born term for high-energy meson-hadron collisions from QCD and chiral quark model

International Nuclear Information System (INIS)

Ochs, W.; Shimada, T.

1988-01-01

Various experimental observations reveal a sizeable hard component in the high-energy 'soft' hadronic collisions. For primary meson beams we propose a QCD Born term which describes the dissociation of the primary meson into a quark-antiquark pair in the gluon field of the target. A pointlike effective pion-quark coupling is assumed as in the chiral quark model by Manohar and Georgi. We derive the total cross sections which for pion beams, for example, are given in terms of f π -2 and some properties of the hadronic final states. In particular, we stress the importance of studying three-jet events in meson-nucleon scattering and discuss the seagull effect. (orig.)

A dependence of exclusive vector meson production in muon-nucleus scattering

International Nuclear Information System (INIS)

Fang, Guang Yin

1993-10-01

Preliminary results on the cross section ratios of exclusive ρ 0 and φ meson production off carbon, calcium, and lead to that off deuterium in deep-inelastic muon-nucleon scattering are reported. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam. The mean beam energy was 470 GeV. Significant increase in the cross section ratios is seen as the four-momentum squared of the virtual photon increases. The results support the idea of color transparency

Measurement of observables in the pion-nucleon system and investigation of charge symmetry in 3H and 3He

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

Nuclear energy density functional from chiral pion-nucleon dynamics revisited

Science.gov (United States)

Kaiser, N.; Weise, W.

2010-05-01

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

Tables of density dependent effective interactions between 122 and 800 MeV

International Nuclear Information System (INIS)

Dortmans, P.J.; Amos, K.

1996-01-01

Coordinate space density dependent effective nucleon-nucleon interaction based upon half-off-shell t and g-matrices are presented. These interactions are based upon the Paris interactions and are presented over a range of energies. 5 refs., 8 tabs

Exclusive Electroproduction of meson rho on the nucleon Virtualite Intermediate With the CLAS Detector at Jlab; Electroproduction Exclusive de meson rho sur le nucleon Virtualite Intermediaire Avec le Detecteur CLAS at Jlab

Energy Technology Data Exchange (ETDEWEB)

Hadjidakis, Cynthia [Univ. of Paris-Sud, Orsay (France). Inst. of Nuclear Physics of Orsay

2002-12-17

This report presents the exclusive rho0 meson electroproduction on the nucleon at intermediate square momentum transfers Q² (1.5 < Q² < 3 GeV²) and above the resonance region. The experiment has been taken place at the Jefferson laboratory with the CLAS detector, with a 4.2 GeV beam energy on a hydrogen target in the February-March 1999 period. They present the results and in particular the L/T separated cross sections. This experimentally unexplored domain experimentally is at the intersection between traditional ''soft'' hadronic physics models (VDM and Regge inspired models) and ''hard'' pQCD inspired approaches (recently introduced Generalized Parton Distribution). They discuss both approaches and their domain of validity.

Studies on inclusive meson resonance and particle production

International Nuclear Information System (INIS)

Saarikko, Heimo

1978-01-01

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

In-medium behaviour of vector mesons and the longitudinal and transverse response functions in (e,e'p) reactions

International Nuclear Information System (INIS)

Soyeur, M.; Brown, G.E.; Rho, M.

1991-01-01

The electromagnetic form factors of nucleons appear dominated by vector mesons at momentum transfers small than ∼ 1 GeV/c. It is therefore expected that measurements of quantities involving the electromagnetic form factors of nucleons embedded in nuclei will be sensitive to changes in vector meson properties arising from their interaction with the medium. Longitudinal and transverse response functions measured in quasi-elastic (e,e'p) reactions provide such data for two very different operators, the charge and the current densities. We show that a decrease of vector meson masses in the medium, consistent with present expectations about chiral symmetry restoration in nuclei, produces the quenching observed in the longitudinal response of light systems ( 3 He, 4 He) and part of this quenching for heavier nuclei 40 Ca where nuclear correlations are expected to generate an additional suppression of the longitudinal response. The transverse response is almost unchanged, in agreement with the data. Difficulties in extrating very quantitative information on the in-medium behaviour of vector mesons from (e,e'p) data are pointed out

Weak interaction in a three nucleon system: search for an asymmetry in radiative capture n-d

International Nuclear Information System (INIS)

Avenier, M.

1982-01-01

Experimental determination of the weak interaction rate in a three nucleon neutron-deuteron system: this weak interaction is observed through pseudoscalar parameters such as the asymetric angular distribution of the capture photon in relation with the system polarization. Orientation of the system is achieved by use of a polarized cold neutron beam. This phenomena is explained as a result of weak coupling between nucleons and mesons. Measurements of the gamma asymmetries observed when tests are conducted with or without heavy water and effects of depolarization are discussed [fr

Hyperon-nucleon and hyperon-hyperon interaction in the quark cluster model

International Nuclear Information System (INIS)

Straub, U.

1988-01-01

The nonrelativistic quark cluster model is used for the description of the hyperon-nucleon and hyperon-hyperon interaction. The different mass of the quarks is consistently regarded in the Hamiltonian and in the shape of the spatial wave functions of the quarks. The six-quark wave function is completely antisymmetrisized. By means of the resonating-group method the dynamic equations for the determination of the binding and scattering states of the six-quark problem are formulated. The corresponding resonating-group kernels are explicitely given. We calculate the lambda-nucleon and sigma-nucleon interaction. The sigma-nucleon scattering in the isospin (T=3/2) channel can be treated in a one-channel calculation. The sigma-nucleon (T=1/2) interaction and the lambda-nucleon interaction are studied in a coupled two-channel calculation. From a fit of the experimental lambda-nucleon interaction cross section the strength of the sigma-meson exchange is determined. The calculation of the sigma-nucleon scattering follows then completely parameterless. The agreement of the theory with the experiment is good. Subsequently the cluster model with this parameter is applied to the dihyperon which is a possibly bound state of two up quarks, two down quarks, and two strange quarks. We solve for this a coupled three-channel calculation. The cluster model presented here gives a binding energy of the dihyperon of (20±5) MeV below the lambda-lambda threshold. The mass of the dihyperon is predicted by this as (2211±5) MeV. (orig.) [de

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.

Nuclear physics brought about by the π-mesons studied from field theory and experiments

International Nuclear Information System (INIS)

Toki, Hiroshi

2012-01-01

In nuclei π-mesons are playing key role. At first the important interactions of π-mesons in light nuclei is explained mentioning that the π-meson exchange force is tensor force. It is pointed out that the importance of π-meson is observed even in the deuterons. By the progress of computations it is possible at present to calculate nuclei up to the mass number of twelve. It is explained then how to handle the π-mesons in heavy nuclei referring to the discovery of the halo of 11 Li and its analysis. Due to the pseudo scalar properties of the π-mesons, tensor force is the strong nucleon-nucleon interaction. It has been necessary to go through numbers of trials and errors to arrive at the discovery of the proper tensor force analysis. It is shown to be possible to handle them in the Tensor-Optimized Shell Model (TOSM) based on the variation method. The explanation of the Extended Brueckner Hartree-Fock (EBHF) method obtained by combining the TOSM with the mean field theory used in the heavy nuclei is given. EBHF theory has the structure including high momentum components in the 2p2h wave functions. Calculated equation of state of symmetric nuclear matter is shown as a function of density in which important contribution of the tensor force is observed. Properties of nuclear matter are discussed. (S. Funahashi)

Photoproduction of η -mesons on protons in the resonance region: The background problem and the third S11-resonance

International Nuclear Information System (INIS)

Tryasuchev, V.A.

2004-01-01

We have constructed an isobar model for the η -photoproduction on the proton in the energy region up to the photon lab energy K 0 = 3 GeV. The database involved into the fitting procedure includes precise results for the cross-section and for the T-asymmetry of the process γp→ηp near threshold obtained at MAMI and ELSA as well as recent results for the Σ -asymmetry and for the angular distribution measured at higher energies in Grenoble and also more recent measurements performed at JLab for the photon energies up to 2 GeV. The model includes twelve nucleon resonances: S 11 (1535), S 11 (1650), S 11 (1825), P 11 (1440), P 13 (1720), D 13 (1520), D 15 (1675), F 15 (1680), F 17 (1990), G 17 (2190), G 19 (2250), H 19 (2220), and the background consisting of the nucleon pole term and the vector meson exchange in the t-channel. To explain the observed energy dependence of the integrated cross-section, two s-wave resonances, S 11 (1650) and S 11 (1825), have to be taken into account along with the dominating S 11 (1535). The integrated cross-section as well as the angular distribution and Σ -asymmetry predicted by the model are in good agreement with the data. Above the photon energy K 0 =2 GeV, the calculated cross-section exhibits an appreciable dependence on the ρ- and ω -meson contribution, whose coupling with nucleons is not well defined. Several versions of extending the model to higher energies are considered. (orig.)

Antinucleon-nucleon annihilation dynamics

International Nuclear Information System (INIS)

Myhrer, F.; Massachusetts Inst. of Tech., Cambridge

1989-01-01

The antinucleon-nucleon annihilation is predominantly described by a hot-fireball process where the many final quantum numbers are distributed in a statistical fashion. It is argued that caution must be used in employing the long-range meson-exchange forces to describe the protonium atomic states. The simplest processes of two final mesons do show puzzling behavior which might be a reflection of quark dynamics, but no guiding principles for these quark calculations have been established yet. (orig.)

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

Off-diagonal helicity density matrix elements for vector mesons produced in polarized e+e- processes

International Nuclear Information System (INIS)

Anselmino, M.; Murgia, F.; Quintairos, P.

1999-04-01

Final state q q-bar interactions give origin to non zero values of the off-diagonal element ρ 1,-1 of the helicity density matrix of vector mesons produced in e + e - annihilations, as confirmed by recent OPAL data on φ, D * and K * 's. New predictions are given for ρ 1,-1 of several mesons produced at large x E and small p T - i.e. collinear with the parent jet - in the annihilation of polarized 3 + and 3 - , the results depend strongly on the elementary dynamics and allow further non trivial tests of the standard model. (author)

Self-consistent relativistic QRPA studies of soft modes and spin-isospin resonances in unstable nuclei

International Nuclear Information System (INIS)

Paar, N.; Niksic, T.; Marketin, T.; Vretenar, D.; Ring, P.

2005-01-01

The excitation phenomena in unstable nuclei are investigated in the framework of the relativistic quasiparticle random-phase approximation (RQRPA) in the relativistic Hartree-Bogolyubov model (RHB) which is extended to include effective interactions with explicit density-dependent meson-nucleon couplings. The properties of the pygmy dipole resonance (PDR) are examined in 132 Sn and within isotopic chains, showing that already at moderate proton-neutron asymmetry the PDR peak energy is located above the neutron emission threshold. A method is suggested for determining the size of the neutron skin within an isotopic chain, based on the measurement of the excitation energies of the Gamow-Teller resonance relative to the isobaric analog state. In addition, for the first time the relativistic RHB+RQRPA model, with tensor ω meson-nucleon couplings, is employed in calculations of β-decay half-lives of nuclei of the relevance for the r-process. (orig.)

Self-consistent relativistic QRPA studies of soft modes and spin-isospin resonances in unstable nuclei

Energy Technology Data Exchange (ETDEWEB)

Paar, N. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); University of Zagreb, Physics Department, Faculty of Science (Croatia); University of Washington, Institute for Nuclear Theory, Seattle (United States); Niksic, T. [University of Zagreb, Physics Department, Faculty of Science (Croatia); University of Washington, Institute for Nuclear Theory, Seattle (United States); Marketin, T.; Vretenar, D. [University of Zagreb, Physics Department, Faculty of Science (Croatia); Ring, P. [Physik-Department der Technischen Universitaet Muenchen, Garching (Germany)

2005-09-01

The excitation phenomena in unstable nuclei are investigated in the framework of the relativistic quasiparticle random-phase approximation (RQRPA) in the relativistic Hartree-Bogolyubov model (RHB) which is extended to include effective interactions with explicit density-dependent meson-nucleon couplings. The properties of the pygmy dipole resonance (PDR) are examined in {sup 132}Sn and within isotopic chains, showing that already at moderate proton-neutron asymmetry the PDR peak energy is located above the neutron emission threshold. A method is suggested for determining the size of the neutron skin within an isotopic chain, based on the measurement of the excitation energies of the Gamow-Teller resonance relative to the isobaric analog state. In addition, for the first time the relativistic RHB+RQRPA model, with tensor {omega} meson-nucleon couplings, is employed in calculations of {beta}-decay half-lives of nuclei of the relevance for the r-process. (orig.)

Multi-reaction-channel fitting calculations in a coupled-channel model : Photoinduced strangeness production

NARCIS (Netherlands)

Scholten, O.; Usov, A.

To describe photo- and meson-induced reactions on the nucleon, one is faced with a rather extensive coupled-channel problem Ignoring the effects of channel coupling, as one would do in describing a certain reaction at the tree level; invariably creates a large inconsistency between the different

Charmonium-nucleon interactions from the time-dependent HAL QCD method

Science.gov (United States)

Sugiura, Takuya; Ikeda, Yoichi; Ishii, Noriyoshi

2018-03-01

The charmonium-nucleon effective central interactions have been computed by the time-dependent HAL QCD method. This gives an updated result of a previous study based on the time-independent method, which is now known to be problematic because of the difficulty in achieving the ground-state saturation. We discuss that the result is consistent with the heavy quark symmetry. No bound state is observed from the analysis of the scattering phase shift; however, this shall lead to a future search of the hidden-charm pentaquarks by considering channel-coupling effects.

Impact Parameter Dependence of the Double Neutron/Proton Ratio of Nucleon Emissions in Isotopic Reaction Systems

International Nuclear Information System (INIS)

Xun-Chao, Zhang; Gao-Chan, Yong; Bao-An, Li; Lie-Wen, Chen

2009-01-01

Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2 fm, 4 fm and 8 fm, respectively. It is found that the double neutron/proton ratio from peripheral collisions is more sensitive to the density dependence of the symmetry energy than those from mid-central and central collisions. (nuclear physics)

Axial charge of the weak nucleon current extracted from the β decays of spin aligned 12B and 12N

International Nuclear Information System (INIS)

Yamaguchi, Takayuki

1998-01-01

The alignment correlation terms in the β-ray angular distributions of the 12 B and 12 N mirror nuclei have been precisely measured, in order to investigate the mesonic effect in the axial charge matrix element. The spin alignments were created with the spin manipulation technique in the β-NMR method, which has been improved based on the recent studies of hyperfine interactions of 12 B and 12 N in a Mg crystal. From the sum of the alignment correlation terms, the ratio of the axial charge to the Gamow-Teller term was determined to be y = 4.66 ± 0.06(stat) ± 0.13(syst). The present result gives clear evidence of the mesonic effect in the axial charge and even more shows 16 ± 6% enhancement over the full calculation which includes the meson exchange effect and the core polarization effect. A possible mass renormalization for the decaying nucleon in a finite nucleon density explains this enhancement. (author)

Weak interaction potentials of nucleons in the Weinberg-Salam model

International Nuclear Information System (INIS)

Lobov, G.A.

1979-01-01

Weak interaction potentials of nucleons due to the nonet vector meson exchange are obtained in the Weinberg-Salam model using the vector-meson dominance. Contribution from the hadronic neutral currents to the weak interaction potential due to the charged pion exchange is obtained. The isotopic structure of the obtained potentials, that is unambiguous in the Weinberg-Salam model, is investigated. Enhancement of the nucleon weak interaction in nuclei resulting from the hadronic neutral currents is discussed. A nuclear one-particle weak interaction potential is presented that is a result of averaging of the two-particle potential over the states of the nuclear core. An approach to the nucleon weak interaction based on the quark model, is discussed. Effects of the nucleon weak interaction in the radiative capture of a thermal neutron by a proton, are considered

The production of $\\rho$, $\\omega$ and $\\phi$ vector-mesons by protons and sulphur ions with incident momentum of 200 GeV/c per nucleon

CERN Document Server

Abreu, M C; Baglin, C; Baldit, C; Bedjidian, M; Bordalo, P; Borges, G; Bussière, A; Castor, J; Chaurand, B; Chevrot, I; Cheynis, B; Devaux, A; Drapier, O; Espagnon, B; Fargeix, J; Ferreira, R; Force, P; Gerschel, C; Grossiord, J Y; Guichard, A; Guimarães, J; Haroutunian, R; Jouan, D; Kluberg, L; Lourenço, C; Mourgues, S; Petiau, P; Pizzi, J R; Quintans, C; Ramos, S; Romana, A; Santos, H; Saturnini, P; Shahoyan, R; Sonderegger, P; Tarrago, X

2005-01-01

The production of rho omega and phi vector-mesons, detected through their mumu decay channel, is studied in p-W, S-S, S-Cu and S-U reactions at 200 GeV/c per nucleon incident momentum. Their inclusive cross-sections are determined in various transverse momentum intervals and their dependence on the projectile and target mass numbers is investigated. The relative yield B/sub mumu/sigma/sub phi //(B/sub mumu/sigmaas a function of the transverse momentum, p/sub T /, and of the collision centrality. While this ratio exhibits no significant dependence with p/sub T/, it clearly increases with the centrality of the collision. Effective temperatures deduced from the transverse mass spectra, dsigma/dM/sub T/, lead to values of Trho +omega equal or slightly higher than T/sub phi/. Both these effective temperatures smoothly increase from p-W to S-U reactions.

QGP thermodynamics and Meson spectroscopy with AdS/CFT

Science.gov (United States)

Erdmenger, J.; Kaminski, M.; Rust, F.

In this talk we present applications of the AdS/CFT correspondence to strongly coupled sys- tems at finite temperature and particle density. The model we investigate contains adjoint matter described by the gauge multiplet of N = 4, as well as fundamental matter given by the hyper- multiplet of N = 2 Super Yang-Mills theory. In some aspects these systems can be thought of as models for the quark-gluon plasma. In the first part we review some properties of meson spectra obtained from these holographic models. We discuss the implications of finite temperature and particle density in these string- theory motivated setups. In particular, we find a broadening of the vector meson peaks in the relevant spectral function at finite density. However, we do not observe a movement of the reso- nances to lower frequencies. Moreover, we analyze the effects of strong coupling on heavy meson diffusion in medium. To do so we make use of an effective model with dipole interaction, which is valid for heavy quarks at arbitrary coupling strength. We calculate the momentum broadening — normalized to the in-medium mass shift — and compare the large ’t Hooft coupling AdS/CFT result with a perturbative result for weak coupling. We find that the momentum broadening is reduced at large ’t Hooft coupling, leading to increased relaxation time.

Real and imaginary part of the potential between two nuclei and the realistic nucleon-nucleon interaction

International Nuclear Information System (INIS)

Trefz, M.

1985-01-01

Starting from a realistic nucleon-nucleon interaction (Reid soft-core) in the model of two infinitely extended confusing nuclear matter complex energy densities are calculated by means of a G matrix. By means of a generalized local-density approximation the results are transferred to finite nuclei. In the framework of the frozen-density approximation in the energy-density formalism a complex potential between two nuclei is calculated. The potential calculated so contains not the contribution of 1-particle-1-hole states to the optical potential. The contribution of these states is therefore calculated in the Feshbach formalism, respectively these states are explicitely regarded in coupled-channel calculations. The model is applied to light (for instance 12 C+ 12 C), medium heavy (for instance 48 Ca+ 48 Ca), and heavy (for instance 40 Ar+ 208 Pb) systems. Potentials for incident energies of 5-84 MeV per projectile nucleon are calculated. By means of these potentials differential cross sections and reaction cross sections are determined and compared with the experimental data. The energy dependence of the reaction cross section is discussed. It is shown that at higher energies (40 MeV/N) the differential cross sections can be quantitatively reproduced. For the reaction cross section in the whole energy range good agreement with the experiment is obtained. Contrarily to current theoretical models it is proved that at low energies the excitation of collective states yields a large contribution to the reaction cross section and therefore must not be neglected. (orig.) [de

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

Science.gov (United States)

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.

Secondary particle multiplicity depending on the collisions of π--mesons with 12C nucleons at p=40 GeV/c

International Nuclear Information System (INIS)

Angelov, N.S.; Grishin, V.G.; Nad', Yu.; Kanarek, T.; Batskovich, S.

1978-01-01

The multiplicities of secondary charged particles in π -12 C-interactions with ν-protons of carbon nucleus at p=40 GeV/c (ν=1-5) is presented. It is shown that the dependence of the average values of particle multiplicities on ν approximately equals the dependence on initial pion energy in π - p-interactions in the range from 40 to 200 GeV. KNO scaling and the Wroblewski empirical law for interactions with several nucleons of 12 C nucleus are observed

Building the nucleus from quarks: The cloudy bag model and the quark description of the nucleon-nucleon wave functions

International Nuclear Information System (INIS)

Miller, G.A.

1984-01-01

In the Cloudy Bag Model hadrons are treated as quarks confined in an M.I.T. bag that is surrounded by a cloud of pions. Computations of the charge and magnetism distributions of nucleons and baryons, pion-nucleon scattering, and the strong and electromagnetic decays of mesons are discussed. Agreement with experimental results is excellent if the nucleon bag radius is in the range between 0.8 and 1.1 fm. Underlying qualitative reasons which cause the pionic corrections to be of the obtained sizes are analyzed. If bags are of such reasonably large sizes, nucleon bags in nuclei will often come into contact. As a result one needs to consider whether explicit quark degrees of freedom are relevant for Nuclear Physics. To study such possibilities a model which treats a nucleus as a collection of baryons, pions and six-quark bags is discussed. In particular, the short distance part of a nucleon-nucleon wave function is treated as six quarks confined in a bag. This approach is used to study the proton-proton weak interaction, the asymptotic D to S state ratio of the deuteron, the pp → dπ reaction, the charge density of /sup 3/He, magnetic moments of /sup 3/He and /sup 3/H and, the /sup 3/He-/sup 3/H binding energy difference. It is found that quark effects are very relevant for understanding nuclear properties

Phase-shift analysis of pion-nucleon elastic scattering below 1.6 GeV; Analyse en ondes partielles de la diffusion elastique meson {pi} - nucleon au-dessous de 1.6 GeV

Energy Technology Data Exchange (ETDEWEB)

Bareyre, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1968-06-01

Experimental results of pion-nucleon elastic scattering below 1.6 GeV (total cross sections, angular distributions of elastic scattering and recoil nucleon polarizations) have been described by a partial wave analysis. This analysis has been developed, one energy at a time, with a method of least squares fits. A single solution is extracted by continuity with energy of the different solutions. Resonating behaviour has been clearly established for several partial waves. In addition to these important effects some phase shifts show rapid variations with energy. Present experimental situation does not permit to say whether these variations are due to experimental biases or to physical effects. (author) [French] Les resultats experimentaux de la diffusion elastique meson {pi} - nucleon au-dessous de 1.6 GeV (sections efficaces totales, distributions angulaires de diffusion elastique et de polarisation du nucleon de recul) sont decrits a l'aide d'une analyse en ondes partielles. Cette analyse est developpee energie par energie au moyen d'une methode d'ajustement en moindres carres. Un critere empirique de continuite des solutions en fonction de l'energie a permis d'isoler une solution unique. Des resonances sont clairement etablies pour plusieurs ondes partielles, ainsi que certains petits effets moins caracteristiques. Pour ceux-ci, la situation experimentale presente ne permet pas d'affirmer s'ils sont dus a des effets physiques ou a des biais experimentaux. (auteur)

On a low energy, strong interaction model, unifying mesons and baryons

International Nuclear Information System (INIS)

Kalafatis, D.

1993-03-01

This thesis is concerned with the study of a unified theory of mesons and baryons. An effective Lagrangian with the low mass mesons, generalizing the Skyrme model, is constructed. The vector meson fields are introduced as gauge fields in the linear sigma model instead of the non linear sigma model. Topological soliton solutions of the model are examined and the nucleon-nucleon interaction in the product approximation is investigated. The leading correction to the classical skyrmion mass, the Casimir energy, is evaluated. The problem of the stability of topological solitons when vector fields enter the chiral Lagrangian is also studied. It is shown that the soliton is stable in very much the same way as with the ωmeson and that peculiar classical doublet solutions do not exist

Oxygen induced reactions at 200 and 60 GeV/nucleon

International Nuclear Information System (INIS)

Gutbrod, H.H.; Albrecht, R.; Claesson, G.; Bock, R.; Kolb, B.W.; Lund, I.; Schmidt, H.R.; Siemiarczuk, T.; Awes, T.C.; Baktash, C.; Ferguson, R.L.; Johnson, J.W.; Lee, I.Y.; Obenshain, F.E.; Plasil, F.; Sorensen, S.P.; Young, G.R.

1988-01-01

The ultimate goal of ultra-relativistic heavy ion physics is the creation and detection of a new form of matter, the so-called Quark-Gluon Plasma (QGP). The QGP is a state of matter in which normal nuclear matter has been compressed to such an extent that the color force field between the constituents of the nucleon is sufficiently screened that a deconfinement phase transition takes place [Sa86]. It is widely believed that the early universe, some 10 -6 seconds after its creation, consisted of this form of primordial matter. This paper shows the space-time evolution of quark matter, created in the laboratory by means of the ultra-relativistic collision of two heavy nuclei. If two nuclei of high energy collide, they will create a zone of hot and dense matter, eventually having an energy density high enough to melt the individual nucleons into a soup of freely moving quarks and gluons, the above described QGP. The QGP will rapidly expand, and quarks will hadronize, mainly into charged and neutral mesons. The (very difficult) experimental task is to search amongst and amidst the abundantly created mesons for signatures of the early QGP phase

Observation of a New Narrow Axial-Vector Meson alpha(1)(1420)

Czech Academy of Sciences Publication Activity Database

Adolph, C.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlák, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Chang, W.-C.; Chiosso, M.; Choi, I.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, E.; Hinterberger, F.; Horikawa, N.; d´Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Jörg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V. I.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Rychter, A.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schmeing, S.; Schmidt, K.; Schlüter, T.; Selyunin, A.; Schmieden, H.; Schönning, K.; Schopferer, S.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

2015-01-01

Roč. 115, č. 8 (2015), 082001:1-6 ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * pion-nucleon scattering * hadron spectroscopy * light-meson spectrum * axial-vector mesons * exotic mesons Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.645, year: 2015

Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach

Energy Technology Data Exchange (ETDEWEB)

Biplab Dey, Michael E. McCracken, David G. Ireland, Curtis A. Meyer

2011-05-01

The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known CGLN formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.

Omega meson production in proton-proton collisions

International Nuclear Information System (INIS)

Schulte-Wissermann, M.; Brinkmann, K.; Dshemuchadse, S.

2005-01-01

The TOF spectrometer is an external experiment fed by the proton accelerator COSY, which is located at the Forschungszentrum Juelich, Germany. While this detector does not utilize a magnetic field for particle identification, it, however, stands out for its high acceptance (approx. 2π in the laboratory frame) and versatility. TOF measures the velocity-vectors of all charged particles, which then are used to completely reconstruct the event pattern. Due to the modular design of the TOF detector, its components can be assembled to ideally match different experimental requirements. This makes it a multipurpose device, which has shown results for many hadronic channels, starting from the pion threshold up to excess energies as high as 1GeV. One of the experimental programs is dedicated to the ω meson production. In proton-proton interactions, this channel has remained largely unstudied until the late 1990s. Then, first experimental data in the direct vicinity of the threshold and at an excess energy of ε=320 MeV became available. We have published data on ω production for two (intermediate) excess energies of ε=93 MeV and ε=173 MeV. In parallel, a considerable interest on the part of theory arose, since the reaction dynamics of ω-meson production in nucleon-nucleon collisions has an impact on many fields of modern physics. For example, there is an ongoing discussion whether 'missing resonances' may (help to) explain the phenomena observed in dense matter. These resonances would couple to the pω, but not to the pπ channel. Although predicted by many authors, until now no pω resonance was found experimentally; the strangeness content of the nucleon is still an open question. One possible key to an answer is the ratio of the total cross sections of ω to φ - mesons, which experimentally is about a factor of seven larger than simple SU predictions (often referred to as 'violation of the OZI-rule'). However, this comparison is only valid assuming similar

Determination of the pion-nucleon coupling constant

International Nuclear Information System (INIS)

Samaranayake, V.K.

1977-06-01

Forward dispersion relations are used to determine the pion-nucleon coupling constant and S-wave scattering lengths using a least squares fit with additional parameters introduced to take account of the uncertainties in the calculation of dispersion integrals. The values obtained are: f 2 = (78.0+- 2.1).10 -3 , a 1 -a 3 = (272.4+- 12.3).10 -3 , a 1 +2a 3 = (15.1+-10.4).10 -3

Modeling a nucleon system: static and dynamical properties - density fluctuations

International Nuclear Information System (INIS)

Idier, D.

1997-01-01

This thesis sets forth a quasi-particle model for the static and dynamical properties of nuclear matter. This model is based on a scale ratio of quasi-particle to nucleons and the projection of the semi-classical distribution on a coherent Gaussian state basis. The first chapter is dealing with the transport equations, particularly with the Vlasov equation for Wigner distribution function. The second one is devoted to the statics of nuclear matter. Here, the sampling effect upon the nuclear density is treated and the state equation of the Gaussian fluid is compared with that given by Hartree-Fock approximation. We define state equation as the relationship between the nucleon binding energy and density, for a given temperature. The curvature around the state equation minimum of the quasi-particle system is shown to be related to the speed of propagation of density perturbation. The volume energy and the surface properties of a (semi-)infinite nucleon system are derived. For the resultant saturated auto-coherent semi-infinite system of quasi-particles the surface coefficient appearing in the mass formula is extracted as well as the system density profile. The third chapter treats the dynamics of the two-particle residual interactions. The effect of different parameters on relaxation of a nucleon system without a mean field is studied by means of a Eulerian and Lagrangian modeling. The fourth chapter treats the volume instabilities (spinodal decomposition) in nuclear matter. The quasi-particle systems, initially prepared in the spinodal region of the utilized interaction, are set to evolve. It is shown then that the scale ratio acts upon the amount of fluctuations injected in the system. The inhomogeneity degree and a proper time are defined and the role of collisions in the spinodal decomposition as well as that of the initial temperature and density, are investigated. Assuming different effective macroscopic interactions, the influence of quantities as

THE ETA-MESON PHOTOPRODUCTION ON PROTON

Czech Academy of Sciences Publication Activity Database

Donoval, Jan; Bydžovský, Petr

2011-01-01

Roč. 26, 3-4 (2011), s. 645-646 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : Eta-meson photoproduction * form factors * nucleon resonances Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011

High energy photoproduction of the rho and rho' vector mesons

International Nuclear Information System (INIS)

Bronstein, J.M.

1977-01-01

In an experiment in the broad band photon beam at Fermilab diffractive production of 2π + and 4π +- states from Be, Al, Cu, and Pb targets was observed. The 2π + data are dominated by the rho(770) and the 4π +- is dominated by the rho'(1500). The energy dependence of rho photoproduction from Be was measured, and no evidence was seen for energy variation of the forward cross section in the range 30 to 160 GeV. The forward cross section is consistent with its average value d sigma/dtlt. slash 0 = 3.42 +- 0.28 μb/GeV 2 over the entire range. For the /sub rho'// a mass of 1487 +- 20 MeV and a width of 675 +- 60 MeV are obtained. All quoted errors are statistical. A standard optical model analysis of the A dependence of the rho and rho'/ photoproduction yields the following results. f/sub rho'/ 2 /f/sub rho/ 2 = 3.7 +- 0.7, sigma /sub rho'//sigma /sub rho/ = 1.05 +- 0.18. Results for the photon coupling constants are in good agreement with GVMD and with the e + e - storage ring results. The approximate equality of the rho-nucleon and rho'-nucleon total cross sections is inconsistent with the diagonal version of GVMD and provides strong motivation for including transitions between different vector mesons in GVMD

Problems of the π meson-nucleus interaction theory

International Nuclear Information System (INIS)

Kopaleishvili, T.I.

1984-01-01

The theory of multiple scattering as applied to PI-meson scattering on nuclei is outlined on the base of optical potential method: first in neglecting the real absorption of a pion by a nucleus and then for the case when this effect is taken into account. The pion interaction with a deuteron is considered both neglecting the pion absorption channel (the relativisitic problem of three bodies) and with account of the absorption channels and pion emission (in this case the problem is solved within the frames of the channel coupling theory for the pion-two nucleus system and the system of two nucleons). Approximate or model solutions to the problem of elastic pion-nuclear scattering primarily in the range of (3.3)-resonance are presented. The formulated theory permits to uniquely describe the observed processes caused by the strong pion interaction with a two-nucleon system

Parity violation in proton-proton scattering at 230 MEV

International Nuclear Information System (INIS)

Birchall, J.; Bowman, J.D.; Davis, C.A.

1988-01-01

Below /similar to/300 MeV six meson-nucleon coupling strengths are required to describe the weak interaction of nucleons. Many experiments have found parity-violating effects in nuclear systems, but only four significant, independent constraints exist. A new measurement is proposed where measurable effects are predicted with minimal dependence on nuclear interaction models, yielding information complementary to previous results. This is a measurement of the parity-violating analyzing power. A/sub z/ in p-p scattering at 230 MeV, which is shown to be sensitive to the weak rho-nucleon coupling. This measurement, at a precision of +- 2 x 10/sup -8/, together with a proposed measurement by the University of Washington group at I.L.L. of the parity-violating neutron spin rotation, will provide the fifth and sixth independent constraints needed to determine the weak meson-nucleon coupling constants

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

D-meson production by muons in the COMPASS experiment at CERN

Energy Technology Data Exchange (ETDEWEB)

Zvyagin, Alexander

2011-01-21

One of the physics goals of the COMPASS experiment at CERN was to measure the contribution of gluons to the nucleon spin. To achieve this, it was proposed to scatter polarized 160 GeV/c muons on a polarized deuteron target and to detect D mesons in the final state. The underlying process in this D meson production is supposed to be the Photon-Gluon Fusion (PGF), where a virtual photon emitted by the muon interacts with a gluon from the target nucleon, producing a charm-anticharm quark pair. Fragmentation of a charm (anticharm) quark leads with high probability to the creation of a D{sup 0} or D{sup *} meson, which COMPASS detects via the D{sup 0}{yields}K{pi} and D{sup *}{yields}D{sup 0}{pi}{yields}K{pi}{pi} decay modes. From the longitudinal cross section spin asymmetries of the D meson production and theoretical predictions for the PGF cross section, the gluon contribution to the nucleon spin has been measured by the COMPASS experiment. The results presented in the thesis are the following. Based on data from the year 2004 a total visible cross section of 1.8{+-}0.4 nb, for the D{sup *} meson production, has been measured, with the error being dominated by systematic effects. It is validated that the D mesons are indeed produced through the PGF process, by comparison of measured D meson kinematic distributions to the ones predicted by a theory (AROMA generator). A good agreement was found for the distribution shapes, which confirms that PGF plays a major role. However, a 20% difference was found in the number of produced D{sup 0} and D{sup 0} mesons (and for the D{sup *+} and D{sup *-} mesons as well) which is significantly larger than predicted by AROMA. Kinematic distributions of D{sup 0} and D{sup *} mesons were compared with the background and also with the nearby K{sup *}{sub 2}(1430){sup 0} resonance, using all longitudinal data taken in 2002-2006. The particle-antiparticle asymmetry has been studied as a function of several kinematic variables. The 20

Transverse charge and magnetization densities in the nucleon's chiral periphery

Energy Technology Data Exchange (ETDEWEB)

Granados, Carlos G. [JLAB Newport News, VA (United States); Weiss, Christian [JLAB Newport News, VA (United States)

2014-01-01

In the light-front description of nucleon structure the electromagnetic form factors are expressed in terms of frame-independent transverse densities of charge and magnetization. Recent work has studied the transverse densities at peripheral distances b = O(M{pi}{sup -1}), where they are governed by universal chiral dynamics and can be computed in a model-independent manner. Of particular interest is the comparison of the peripheral charge and magnetization densities. We summarize (a) their interpretation as spin-independent and -dependent current matrix elements; (b) the leading-order chiral effective field theory results; (c) their mechanical interpretation in the light-front formulation; (d) the large-N_c limit of QCD and the role of {Delta} intermediate states; (e) the connection with generalized parton distributions and peripheral high-energy scattering processes.

Density-dependent Hartree-Fock response functions in quasi-elastic electron scattering on 12C and related sum rules

International Nuclear Information System (INIS)

Kohno, M.

1983-01-01

We report fully consistent calculations of the longitudinal and transverse response functions of the inclusive quasi-elastic electron scattering on 12 C in the Hartree-Fock approximation. The distorted wave for the outgoing nucleon is constructed from the same non-local Hartree-Fock field as in the ground-state description. Thus the orthogonality and Pauli principle requirements are naturally satisfied. The theoretical prediction, based on the standard density-dependent effective interaction (GO force), shows a good correspondence to the experimental data. Since the calculated response functions automatically satisfy the relevant sum rule, this work illuminates the well-known puzzle concerning the longitudinal part, which remains to be solved. We study the energy-weighted sum rules and discuss effects beyond the mean-field approximation. Meson-exchange-current contributions to the transverse response function are also estimated and found to be small due to cancellations among them. (orig.)

Channel coupling in A(e,e N)B reactions

CERN Document Server

Kell, J

1999-01-01

The sensitivity of momentum distributions, recoil polarization observables, and response functions for nucleon knockout by polarized electron scattering to channel coupling in final-state interactions is investigated using a model in which both the distorting and the coupling potentials are constructed by folding density-dependent nucleon-nucleon effective interactions with nuclear transition densities. Elastic reorientation, inelastic scattering, and charge exchange are included for all possible couplings within the model space. Calculations for sup 1 sup 6 O are presented for 200 and 433 MeV ejectile energies, corresponding to proposed experiments at MAMI and TJNAF, and for sup 1 sup 2 C at 70 and 270 MeV, corresponding to experiments at NIKHEF and MIT-Bates. The relative importance of charge exchange decreases as the ejectile energy increases, but remains significant for 200 MeV. Both proton and neutron knockout cross sections for large recoil momenta, p sub m greater than 300 MeV/c, are substantially affe...

Nucleon-deuteron scattering with Δ-isobar excitation: Perturbation theory

International Nuclear Information System (INIS)

Deltuva, A.; Chmielewski, K.; Sauer, P.U.

2003-01-01

A perturbative approach for the description of elastic and inelastic nucleon-deuteron scattering is developed. Its validity is discussed. The aim of the perturbative approach is the isolation of details of different reaction mechanisms. The dynamics is based on a two-baryon potential allowing for the excitation of a nucleon to a Δ isobar. The coupled-channel potential yields an effective three-nucleon force in three-nucleon scattering. The purely nucleonic reference potential is the charge-dependent CD-Bonn potential

Photoproduction de Mesons sur le Nucleon aux Energies Intermediaire (in French) [Photoproduction of mesons on the nucleon at intermediate energies

Energy Technology Data Exchange (ETDEWEB)

Guidal, Michel [Univ. of Paris, Orsay (France)

1996-12-13

One object of this thesis is to propose a model taking account of low transfer reaction mechanisms for a series of photoproduction reactions on nucleons for photon energies ≳4 GeV. If our comprehension of processes with low transfers is correct, then extrapolating our model in the domain of large transfers and the comparison with data supplied will give us information on the domains in energy and transfers from which an interpretation of reactions in terms of the "soft" process ceases to be valid. In the domain of large transfers, only one approach in terms of "hard" process can then explain the data. We are interested in electromagnetic photoproduction reactions because the probe, firstly, interacts with the target via an exact and well known mechanism (described by the QED theory) and also eliminates the interaction phenomena in the initial state. No probe is as well known as the photon. The extraction of reaction mechanisms, amplitudes and coupling constants match is made easier than in the case of hadronic probes. The energy domain 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

Azimuthal anisotropy of D -meson production in Pb-Pb collisions at sNN =2.76 TeV

NARCIS (Netherlands)

Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Baumann, C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Belmont, R.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Berger, M. E.; Bertens, R. A.|info:eu-repo/dai/nl/371577810; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.|info:eu-repo/dai/nl/371578248; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Bjelogrlic, S.|info:eu-repo/dai/nl/355079615; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Böhmer, F. V.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossú, F.; Botje, M.|info:eu-repo/dai/nl/070139032; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.|info:eu-repo/dai/nl/411885812; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Casula, E. A R; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.|info:eu-repo/dai/nl/411888056; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, D.; Das, I.; Das, K.; Das, S.; Dash, A.; Dash, S.; De, S.; Delagrange, H.; Deloff, A.; Dénes, E.; D'Erasmo, G.; De Caro, A.; De Cataldo, G.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Rooij, R.|info:eu-repo/dai/nl/315888644; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Di Bari, D.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Djuvsland, O.; Dobrin, A.|info:eu-repo/dai/nl/372618715; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dørheim, S.; Dubey, A. K.; Dubla, A.|info:eu-repo/dai/nl/355502488; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Hilden, T. E.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Eschweiler, D.; Espagnon, B.; Esposito, M.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A S; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Graczykowski, L. K.; Grajcarek, R.; Grelli, A.|info:eu-repo/dai/nl/326052577; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J. Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gumbo, M.; Gunji, T.; Gupta, A.; Gupta, R.; Khan, K. H.; Haake, R.; Haaland, O.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hippolyte, B.; Hladky, J.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Innocenti, G. M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H S Y; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kadyshevskiy, V.; Kalcher, S.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L D|info:eu-repo/dai/nl/370530780; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kramer, F.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.|info:eu-repo/dai/nl/362845670; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.|info:eu-repo/dai/nl/074064975; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; Ladron De Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; La Pointe, S. L.|info:eu-repo/dai/nl/355080192; La Rocca, P.; Lea, R.; Leardini, L.; Lee, G. R.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Leoncino, M.; León Monzón, I.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Lopez, X.; López Torres, E.; Lu, X. G.; Luettig, P.; Lunardon, M.; Luparello, G.|info:eu-repo/dai/nl/355080400; Ma, R.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martin Blanco, J.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.|info:eu-repo/dai/nl/325781435; Mishra, A. N.; Mis̈kowiec, D.; Mitra, J.; Mitu, C. M.; Mlynarz, J.; Mohammadi, N.|info:eu-repo/dai/nl/369405870; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Noferini, F.; Nomokonov, P.; Nooren, G.|info:eu-repo/dai/nl/07051349X; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Okatan, A.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.|info:eu-repo/dai/nl/323375618; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Sahoo, P.; Pachmayer, Y.; Pachr, M.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palmeri, A.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.|info:eu-repo/dai/nl/304833959; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Pesci, A.; Peskov, V.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L M; Poghosyan, M. G.; Pohjoisaho, E. H O; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Rauf, A. W.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.|info:eu-repo/dai/nl/32823219X; Reidt, F.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J. P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohni, S.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, R.; Sahu, P. K.; Saini, J.; Sakai, S.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sánchez Rodríguez, F. J.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Segato, G.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Shangaraev, A.; Sharma, N.; Sharma, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Sicking, E.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J M|info:eu-repo/dai/nl/165585781; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A P; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J M; Szabo, A.; Szanto De Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; Van Der Maarel, J.|info:eu-repo/dai/nl/412860996; Van Hoorne, J. W.; Van Leeuwen, M.|info:eu-repo/dai/nl/304836737; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; Von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wagner, V.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C S; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yang, S.; Yano, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I. K.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zaman, A.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, F.|info:eu-repo/dai/nl/304845035; Zhou, Y.; Zhou, Zhuo; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zoccarato, Y.; Zyzak, M.

2014-01-01

The production of the prompt charmed mesons D0, D+, and D∗+ relative to the reaction plane was measured in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision of sNN=2.76TeV with the ALICE detector at the CERN Large Hadron Collider. D mesons were reconstructed via their

On the mesonic-exchange currents in the photomesic reactions

International Nuclear Information System (INIS)

Lazard, C.; Maric, Z.; Zivanovic, D.

1979-02-01

The γd→π 0 d reaction is analysed in the framework of the relativistic many-body theory with mesonic degrees of freedom explicitly present. It is shown that the mesonic correlations can be grouped into transition operators containing vertices of some elementary reactions between photon, nucleons and pions. The wave function corrections due to meson exchange currents are included in the transition operators and the S-matrix is obtained with the non relativistic deuteron wave function

Hypernuclei and hyperon-nucleon interactions

International Nuclear Information System (INIS)

Yamamoto, Yasuo

1994-01-01

The properties of baryon many-body systems which contain nucleons and hyperons with strangeness link closely to the underlying hyperon(Y)-nucleon(N) and YY interactions. It is very convenient to derive effective interactions in nuclear media from those in free space. The G-matrix gives a good starting point for such approach. It is possible and important to explore the properties of YN and YY interactions, and test their theoretical models by analyzing hypernuclear phenomena. In this work, the G-matrix interaction of the baryon pair in a nuclear matter was derived. The coupling effect between different baryon channels is renormalized into the G-matrix. The density dependence of the resultant G-matrix originates from the repulsive core singularity, the tensor force and also the coupling between different baryon channels. For the application to various hypernuclear problems, it is convenient to construct effective local potentials which simulate the G-matrices. Those are parameterized in a three-range Gaussian form. The parameters are determined so as to simulate the calculated G-matrices. The effective interactions are called YNG-ND, NF, NS, JA and JB. The data on ΛN, ΣN, ΛΛ and ΣN interactions are given. (K.I.)

Medium modifications of nucleon electromagnetic form factors

Energy Technology Data Exchange (ETDEWEB)

Horikawa, T. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan); Bentz, W. [Department of Physics, School of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-1292 (Japan)]. E-mail: bentz@keyaki.cc.u-tokai.ac.jp

2005-11-28

We use the Nambu-Jona-Lasinio model as an effective quark theory to investigate the medium modifications of the nucleon electromagnetic form factors. By using the equation of state of nuclear matter derived in this model, we discuss the results based on the naive quark-scalar diquark picture, the effects of finite diquark size, and the meson cloud around the constituent quarks. We apply this description to the longitudinal response function for quasielastic electron scattering. RPA correlations, based on the nucleon-nucleon interaction derived in the same model, are also taken into account in the calculation of the response function.

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

Nuclear energy density functional from chiral pion-nucleon dynamics revisited

OpenAIRE

Kaiser, N.; Weise, W.

2009-01-01

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

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)

submitter Time-dependent CP violation in charm mesons

CERN Document Server

Inguglia, Gianluca

CP violation is a well established phenomenon for B and K mesons, but for D0 mesons, bound states made up of a quark-antiquark pair containing a charm quark, a conclusive answer to the question whether there is CP vio- lation or not, has yet to be determined. I show here the phenomenology of time-dependent CP asymmetries in charm decays, and discuss the implica- tions of experimental tests aimed at the measurement of CP violation in the interference between mixing and decays of charm mesons, in particular when studying the decay channels D0 ! h+h (h = K; ). The decay channels considered can also be used to constrain quantities that are poorly measured or still to be investigated, such as MIX and c;eff , provided that the e ects of penguin pollution are ignored. I considered correlated production of D0 mesons at the SuperB experiment and its planned asymmetric run at the charm threshold and performed a study of simulated events, nding that a boost factor = 0:28 would not be su cient to produce competitive re- ...

Techniques in meson spectroscopy

International Nuclear Information System (INIS)

Longacre, R.S.

1991-01-01

This report contains lectures on the following topics: the quark model and beyond using quantum chromodynamics; analysis of formation reactions; energy dependence of the partial wave amplitudes; where the data for the t-matrix analysis comes from; and coupled channel analysis of isoscalar mesons

Nuclear spin-isospin excitations from covariant quasiparticle-vibration coupling

Science.gov (United States)

Robin, Caroline; Litvinova, Elena

2016-09-01

Methods based on the relativistic Lagrangian of quantum hadrodynamics and nuclear field theory provide a consistent framework for the description of nuclear excitations, naturally connecting the high- and medium-energy scales of mesons to the low-energy domain of nucleonic collective motion. Applied in the neutral channel, this approach has been quite successful in describing the overall transition strength up to high excitation energies, as well as fine details of the low-lying distribution. Recently, this method has been extended to the description of spin-isospin excitations in open-shell nuclei. In the charge-exchange channel, the coupling between nucleons and collective vibrations generates a time-dependent proton-neutron effective interaction, in addition to the static pion and rho-meson exchange, and introduces complex configurations that induce fragmentation and spreading of the resonances. Such effects have a great impact on the quenching of the strength and on the computing of weak reaction rates that are needed for astrophysics modeling. Gamow-Teller transitions in medium-mass nuclei and associated beta-decay half-lives will be presented. Further developments aiming to include additional ground-state correlations will also be discussed. This work is supported by US-NSF Grants PHY-1404343 and PHY-1204486.

Three-nucleon hadronic and electromagnetic reactions with Δ-isobar excitation

International Nuclear Information System (INIS)

Deltuva, A.; Adam, J. Jr.; Fonseca, A.C.; Sauer, P.U.

2005-01-01

Three-nucleon hadronic and electromagnetic reactions are described. The description uses the purely nucleonic charge-dependent CD-Bonn potential and its coupled-channel extension CD-Bonn + Δ. Exact solutions of three-particle equations are employed for the initial and final states of the reactions. The Δ-isobar excitation yields an effective three-nucleon force and effective two- and three-nucleon currents beside other Δ-isobar effects; they are mutually consistent

Spectra and hadronic couplings of light hermaphrodite mesons

International Nuclear Information System (INIS)

Latorre, J.I.; Pascual, P.

1987-01-01

We clarify the discrepancies of previous results for the masses and decay amplitudes of hermaphrodite mesons obtained from QCD sum rules. We study the case of the strange quark within a light quark expansion formalism. We find that the hermaphrodite masses are much higher than the ones of their ordinary meson partners. Our values of the set of masses and continuum thresholds are compared with some other sum rule results. We analyze the hadronic couplings of the isovector 1 -+ exotic hermaprodite ρ tilde using a three-point function sum rule evaluated at the symmetric euclidean point. We find that the ρ tilde can be very broad and prefers to decay into ρπ and K * K. Its most characteristic decays are the ones into πγ, ηπ and η'π. The former and the latter are of the order of (3∝8) MeV. (orig.)

Spectra and hadronic couplings of light hermaphrodite mesons

International Nuclear Information System (INIS)

Latorre, J.I.; Pascual, P.; Narison, S.

1985-12-01

We clarify the discrepancies of previous results for the masses and decay amplitudes of hermaphrodite mesons obtained from QCD sum rules. We study the case of the strange quark within a light quark expansion formalism. We find that the hermaphrodite masses are much higher than the ones of their ordinary meson partners. Our values of the set of masses and continuum thresholds are compared with some other sum rule results. We analyze the hadronic couplings of the isovector 1 -+ exotic hermaphrodite rho-tilde using a three-point function sum rule evaluated at the symmetric euclidean point. We find that the rho-tilde can be very broad and prefers to decay into rhoπ and K*K. Its most characteristic decays are the ones into πγ, etaπ and eta'π. The former and the latter are of the order of (3 to 8) MeV. (author)

Quark-Meson-Coupling (QMC) model for finite nuclei, nuclear matter and beyond

Science.gov (United States)

Guichon, P. A. M.; Stone, J. R.; Thomas, A. W.

2018-05-01

The Quark-Meson-Coupling model, which self-consistently relates the dynamics of the internal quark structure of a hadron to the relativistic mean fields arising in nuclear matter, provides a natural explanation to many open questions in low energy nuclear physics, including the origin of many-body nuclear forces and their saturation, the spin-orbit interaction and properties of hadronic matter at a wide range of densities up to those occurring in the cores of neutron stars. Here we focus on four aspects of the model (i) a full comprehensive survey of the theory, including the latest developments, (ii) extensive application of the model to ground state properties of finite nuclei and hypernuclei, with a discussion of similarities and differences between the QMC and Skyrme energy density functionals, (iii) equilibrium conditions and composition of hadronic matter in cold and warm neutron stars and their comparison with the outcome of relativistic mean-field theories and, (iv) tests of the fundamental idea that hadron structure changes in-medium.

$\\phi$ production in Pb-Pb collisions at 158 GeV/c per nucleon incident momentum

CERN Document Server

Alessandro, B; Arnaldi, R; Astruc, J; Atayan, M; Baglin, C; Baldit, A; Beolè, S; Boldea, V; Bordalo, P; Borges, G; Bussière, A; Capelli, L; Caponi, V; 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; Cruz, J; 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; Grigoryanm, S; Grossiord, J Y; Guber, F F; Guichard, A; Gulkanian, H R; Hakobyan, R S; 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; Da Silva, W; 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

2003-01-01

The production of vector mesons phi , rho and omega has been measured in Pb-Pb collisions at 158 GeV/c per nucleon incident momentum at the CERN/SPS. The muon spectrometer of experiment NA50 detects phi , rho and omega mesons via their mu /sup +/ mu /sup -/ decay channel in the collision center of mass rapidity range 0 nucleon (N/sub part/) increase with the centrality of the collision. On the other hand, the ( rho + omega ) multiplicity per participant does not exhibit any N/sub pat/ dependence within our errors. The inverse slope parameter as deduced from an exponential fit to the phi transverse mass distribution is 228 +or- 10 MeV. Our results are compared with those obtained by experiment NA49 and with theoretical calculations. (26 refs).

Dynamical coupled channel approach to omega meson production

Energy Technology Data Exchange (ETDEWEB)

Mark Paris

2007-09-10

The dynamical coupled channel approach of Matsuyama, Sato, and Lee is used to study the $\\omega$--meson production induced by pions and photons scattering from the proton. The parameters of the model are fixed in a two-channel (\\omega N,\\pi N) calculation for the non-resonant and resonant contributions to the $T$ matrix by fitting the available unpolarized differential cross section data. The polarized photon beam asymmetry is predicted and compared to existing data.

Nucleonic density gauging -- an application in a chemical industry

International Nuclear Information System (INIS)

Rao, S.S.; Kirti; Jain, S.K.

1979-01-01

Hardly any conventional technique is available for on-line bulk density measurement. A typical problem of measurement of bulk density of detergent powder during production has been tackled. The nucleonic bulk density gauge developed by the Bhabha Atomic Research Centre, Bombay, is briefly explained. Problems of source selection, collimation of radiation, detection system, etc are described. Adequate compensation for environmental temperature changes was achieved. Tests on stability, etc were carried out in the laboratory and the plant. The experience in actual use is mentioned. With some modifications the system developed can be extended for density measurement and control of liquids, slurries, etc. Improvement in output linearity is also possible. (auth.)

Determination of the pion-nucleon coupling constant and scattering lengths

CERN Document Server

Ericson, Torleif Eric Oskar; Thomas, A W

2002-01-01

We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data a pseudoscalar coupling constant of 14.17+-0.05(statistical)+-0.19(systematic) or a pseudovector one of 0.0786(11). This value is intermediate between that of indirect methods and the direct determination from backward neutron-proton differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the negatively charged pion-proton and pion-neutron scattering lengths with high precision. The symmetric sum gives 0.0017+-0.0002(statistical)+-0.0008 (systematic) and the antisymmetric one 0.0900+-0.0003(statistical)+-0.0013(systematic), both in units of inverse charged pi...

Meson-baryon components in the states of the baryon decuplet

Energy Technology Data Exchange (ETDEWEB)

Aceti, F.; Oset, E. [Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigacion de Paterna, Departamento de Fisica Teorica y IFIC, Valencia (Spain); Kavli Institute for Theoretical Physics China, Beijing (China); Dai, L.R. [Liaoning Normal University, Department of Physics, Dalian (China); Kavli Institute for Theoretical Physics China, Beijing (China); Geng, L.S. [Beihang University, School of Physics and Nuclear Energy Engineering and International Research Center for Nuclei and Particles in the Cosmos, Beijing (China); Zhang, Y. [Liaoning Normal University, Department of Physics, Dalian (China)

2014-03-15

We apply an extension of the Weinberg compositeness condition on partial waves of L = 1 and resonant states to determine the weight of the meson-baryon component in the Δ(1232) resonance and the other members of the J{sup P} = (3)/(2){sup +} baryon decuplet. We obtain an appreciable weight of πN in the Δ(1232) wave function, of the order of 60%, which looks more natural when one recalls that experiments on deep inelastic and Drell Yan give a fraction of πN component of 34% for the nucleon. We also show that, as we go to higher energies in the members of the decuplet, the weights of the meson-baryon component decrease and they already show a dominant part for a genuine, non-meson-baryon, component in the wave function. We write a section to interpret the meaning of the Weinberg sum rule when it is extended to complex energies and another one for the case of an energy-dependent potential. (orig.)

Radiative decays of vector mesons in the chiral bag model

International Nuclear Information System (INIS)

Tabachenko, A.N.

1988-01-01

A new model of radiative π-meson decays of vector mesons in the chiral bag model is proposed. The quark-π-meson interaction has the form of a pseudoscalar coupling and is located on the bag surface. The vector meson decay width depends on the quark masses, the π-meson decay constant, the radius of the bag, and the free parameter Z 2 , which specifies the disappearance of the bag during the decay. The obtained results for the omega- and p-decay widths are in satisfactory agreement with the experiment

Two-current nucleon observables in Skyrme model

International Nuclear Information System (INIS)

Chemtob, M.

1987-01-01

Three independent two-current nucleon observables are studied within the two-flavor Skyrme model for the πρω system. The effecive lagrangian is that of the gauged chiral symmetry approach, consistent with the vector meson dominance, in the linear realization (for the vector mesons) of the global chiral symmetry. The first application deals with the nucleon electric polarizability and magnetic susceptibility. Both seagull and dispersive contributions appear and we evaluate the latter in terms of the sums over intermediate states. The results are compared with existing quark model results as well as with empirical determinations. The second application concerns the zero-point quantum correction to the skyrmion mass. We apply a chiral perturbation theory approach to evaluate the ion loop contribution to the nucleon mass. The comparison with the conventional Skyrme model result reveals an important sensitivity to the stabilization mechanism. The third application is to lepton-nucleon deep inelastic scattering in the Bjorken scaling limit. The structure tensor is calculated in terms of the representation as a commutator product of two currents. Numerical results are presented for the scaling function F 2 (x). An essential use is made of the large N c (number of colors) approximation in all these applications. In the numerical computations we ignore the distortion effects, relative to the free plane wave limit, on the pionic fluctuations. (orig.)

Off-diagonal helicity density matrix elements for vector mesons produced at LEP

International Nuclear Information System (INIS)

Anselmino, M.; Bertini, M.; Quintairos, P.

1997-05-01

Final state q q-bar interactions may give origin to non zero values of the off-diagonal element ρ 1 of the helicity density matrix of vector mesons produced in e + e - annihilations, as confirmed by recent OPAL data on φ and D * 's. Predictions are given for ρ1,-1 of several mesons produced at large z and small PT, collinear with the parent jet; the values obtained for θ and D * are in agreement with data. (author)

Hadronic Lorentz violation in chiral perturbation theory including the coupling to external fields

Science.gov (United States)

Kamand, Rasha; Altschul, Brett; Schindler, Matthias R.

2018-05-01

If any violation of Lorentz symmetry exists in the hadron sector, its ultimate origins must lie at the quark level. We continue the analysis of how the theories at these two levels are connected, using chiral perturbation theory. Considering a 2-flavor quark theory, with dimension-4 operators that break Lorentz symmetry, we derive a low-energy theory of pions and nucleons that is invariant under local chiral transformations and includes the coupling to external fields. The pure meson and baryon sectors, as well as the couplings between them and the couplings to external electromagnetic and weak gauge fields, contain forms of Lorentz violation which depend on linear combinations of quark-level coefficients. In particular, at leading order the electromagnetic couplings depend on the very same combinations as appear in the free particle propagators. This means that observations of electromagnetic processes involving hadrons—such as vacuum Cerenkov radiation, which may be allowed in Lorentz-violating theories—can only reliably constrain certain particular combinations of quark coefficients.

New ways to access the transverse spin content of the nucleon

International Nuclear Information System (INIS)

Beiyad, M El; Pire, B; Szymanowski, L; Wallon, S

2011-01-01

We first describe a new way to access the chiral odd transversity parton distribution in the proton through the photoproduction of lepton pairs. The basic ingredient is the interference of the usual Bethe-Heitler or Drell-Yan amplitudes with the amplitude of a process, where the photon couples to quarks through its chiral-odd distribution amplitude, which is normalized to the magnetic susceptibility of the QCD vacuum. We also show how the chiral-odd transversity generalized parton distributions (GPDs) of the nucleon can be accessed experimentally through the exclusive electro - or photoproduction process of a meson pair with a large invariant mass and when the final nucleon has a small transverse momentum. We calculate perturbatively the scattering amplitude at leading order, both in the high energy domain which may be accessed in electron-ion colliders and in the medium energy range. Estimated rates are encouraging.

Contribution to the study of the antinucleon-nucleon interactions

International Nuclear Information System (INIS)

Moussallam, B.

1985-01-01

A potential for the antinucleon-nucleon system is constructed. It has an imaginary part of very short range, respecting theoretical constraints. This implies a significant dependence on spin and isospin, and also on the energy. The spectrum of resonances is computed using an original method. One state (I=0 j PC =0 ++ ) could be easily detected. A model is proposed for a class of inelastic reactions: NantiN #-> # 2 mesons. Using a distorted-wave-Born approximation, comparisons with experiment are made. Finally, we consider some aspects of the atomic pantip system (protonium) [fr

Symmetry energy, its density slope, and neutron-proton effective mass splitting at normal density extracted from global nucleon optical potentials

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.

Effects of medium-induced ρ-ω meson mixing on the equation of state in isospin-asymmetric nuclear matter

International Nuclear Information System (INIS)

Jiang Weizhou; Li Baoan

2009-01-01

We reexamine effects of the ρ-ω meson mixing mediated by nucleon polarizations on the symmetry energy in isospin-asymmetric nuclear matter. Taking into account the rearrangement term neglected in previous studies by others, we evaluate the ρ-ω mixing angle in a novel way within the relativistic mean-field models with and without chiral limits. It is found that the symmetry energy is significantly softened at high densities contrary to the finding in earlier studies. As the first step of going beyond the lowest-order calculations, we also solve the Dyson equation for the ρ-ω mixing. In this case, it is found that the symmetry energy is not only significantly softened by the ρ-ωmixing at suprasaturation densities, similar to the lowest-order ρ-ω mixing, but interestingly also softened at subsaturation densities. In addition, the softening of the symmetry energy at subsaturation densities can be partly suppressed by the nonlinear self-interaction of the σ meson.

ω(→ π+π−π0) meson photoproduction on proton

Indian Academy of Sciences (India)

PRAMANA c Indian Academy of Sciences. Vol. 75, No. 4. — journal of. October 2010 physics pp. 665–674 ω(→ π+π−π0) meson photoproduction on proton ... The vector meson can probe the low-lying nucleonic resonances [7] because it ... reaction amplitudes from the latest measurement of the four-momentum transfer.

Effects of in-medium nucleon-nucleon cross sections on stopping observable and ratio of free protons in heavy-ion collisions at 400 MeV/nucleon

Energy Technology Data Exchange (ETDEWEB)

Su, Jun; Huang, Ching-Yuan [Sun Yat-sen University, Sino-French Institute of Nuclear Engineering and Technology, Zhuhai (China); Xie, Wen-Jie [Yuncheng University, Department of Physics, Yuncheng (China); Chinese Academy of Sciences, Institute of Modern Physics, Lanzhou (China); Zhang, Feng-Shou [Beijing Normal University, The Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing (China); Beijing Radiation Center, Beijing (China); National Laboratory of Heavy Ion Accelerator of Lanzhou, Center of Theoretical Nuclear Physics, Lanzhou (China)

2016-07-15

The effects of in-medium nucleon-nucleon cross sections on the stopping observable and ratio of free protons in heavy-ion collisions at 400 MeV/nucleon have been investigated within the framework of the IQMD+GEMINI model. Five kinds of in-medium corrections of nucleon-nucleon cross sections, which are considerably different in the referred energy and density, have been used in the model. It has been found that calculations of the stopping decrease when the in-medium cross sections decrease. Moreover, the ratio of free protons R{sub p} depends not only on the value of the in-medium factors but also on its isospin dependence. In order to investigate the isospin effect of in-medium factors on the ratio of free protons R{sub p}, the isospin dependence of in-medium factors has been adjusted and used in the model. The calculations have shown that the isospin dependence of in-medium factors does not impact the stopping, but impacts the ratio of free protons R{sub p}. When the in-medium factors relation f{sub nn}{sup med} > f{sub pp}{sup med} is used in the model, the calculated values of R{sub p} are larger than those in the f{sub nn}{sup med} < f{sub pp}{sup med} case. (orig.)

Reaction channel coupling effects for nucleons on 16O: Induced undularity and proton-neutron potential differences

Science.gov (United States)

Keeley, N.; Mackintosh, R. S.

2018-01-01

Background: Precise fitting of scattering observables suggests that the nucleon-nucleus interaction is l dependent. Such l dependence has been shown to be S -matrix equivalent to an undulatory l -independent potential. The undulations include radial regions where the imaginary term is emissive. Purpose: To study the dynamical polarization potential (DPP) generated in proton-16O and neutron-16O interaction potentials by coupling to pickup channels. Undulatory features occurring in these DPPs can be compared with corresponding features of empirical optical model potentials (OMPs). Furthermore, the additional inclusion of coupling to vibrational states of the target will provide evidence for dynamically generated nonlocality. Methods: The fresco code provides the elastic channel S -matrix Sl j for chosen channel couplings. Inversion, Sl j→V (r ) +l .s VSO(r ) , followed by subtraction of the bare potential, yields an l -independent and local representation of the DPP due to the chosen couplings. Results: The DPPs have strongly undulatory features, including radial regions of emissivity. Certain features of empirical DPPs appear, e.g., the full inverted potential has emissive regions. The DPPs for different collective states are additive except near the nuclear center, whereas the collective and reaction channel DPPs are distinctly nonadditive over a considerable radial range, indicating dynamical nonlocality. Substantial differences between the DPPs due to pickup coupling for protons and neutrons occur; these imply a greater difference between proton and neutron OMPs than the standard phenomenological prescription. Conclusions: The onus is on those who object to undularity in the local and l -independent representation of nucleon elastic scattering to show why such undulations do not occur. This work suggests that it is not legitimate to halt model-independent fits to high-quality data at the appearance of undularity.

Distance- and momentum-dependence of modern nucleon-nucleon interactions

International Nuclear Information System (INIS)

Feldmeier, Hans; Neff, Thomas; Weber, Dennis

2015-01-01

A phase-space representation of nuclear interactions, which depends on the distance r vector and relative momentum p vector of the nucleons, is presented. It visualizes in an intuitive way the non-local behavior introduced by cutoffs in momentum space or renormalization procedures that are used to adapt the interaction to low momentum many-body Hilbert spaces, as done in the unitary correlation operator method (UCOM) or with the similarity renormalization group (SRG). It allows to develop intuition about the various interactions and illustrates how the softened interactions reduce the short-range repulsion in favor of non-locality or momentum dependence while keeping the scattering phase shifts invariant. It also reveals that these effective interactions can have undesired complicated momentum dependencies at momenta around and above the Fermi momentum. Properties, similarities, and differences of the Argonne and the N3LO chiral potential, and their UCOM and SRG derivatives are discussed. (author)

Hyperon-meson and delta-meson coupling to protoneutron stars structure using the nonlinear Walecka model

International Nuclear Information System (INIS)

Souto, W A; Oliveira, J C T; Rodrigues, H; Duarte, S B; Chiapparini, M

2015-01-01

In this work we determine the equation of state and the population of baryons and leptons and discuss the effects of the hyperon-meson coupling constants to the formation of delta resonances in the stellar medium. We also discuss the structure of the protoneutron stars including the delta matter in their composition, and compared the results of a cooled neutron star, after escape of neutrinos. For protoneutron stars structure and composition, the neutrinos are considered trapped. (paper)

Relativistic QRPA Calculation of β-Decay Rates of r-process Nuclei

International Nuclear Information System (INIS)

Marketin, T.; Paar, N.; Niksic, T.; Vretenar, D.; Ring, P.

2009-01-01

A systematic, fully self-consistent calculation of β-decay rates is presented, based on a microscopic theoretical framework. Analysis is performed on a large number of nuclei from the valley of β stability towards the neutron drip-line. Nuclear ground state is determined using the Relativistic Hartree-Bogoliubov (RHB) model with density-dependent meson-nucleon coupling constants. Transition rates are calculated within the proton-neutron relativistic quasiparticle RPA (pn-RQRPA) using the same interaction that was used in the RHB equations.

Total disintegration of three-nucleon nuclei in charged-pion photo-production

International Nuclear Information System (INIS)

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

1984-01-01

The total disintegration of three-nucleon nuclei in charged-pion photo-production is studied within the framework of the microscopic approach based on the method of hyperspherical functions. The initial and final nuclear states are described using the same NN potentials. The differential and total cross sections are calculated using various NN potentials. It is shown that the cross sections are sensitive to the form of the NN interaction and to the final-state interaction of the three nucleons. It is found that the cross section for π - meson production is systematically larger than the cross section for π + meson production. The importance of an experimental investigation of these reactions is shown

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.)

Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

Energy Technology Data Exchange (ETDEWEB)

Hilger, Thomas Uwe

2012-04-11

The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Role of vector mesons in pion electroproduction

International Nuclear Information System (INIS)

Uleshchenko, V.V.

2007-01-01

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

Kaon-Nucleon scattering in a constituent quark model

International Nuclear Information System (INIS)

Lemaire, S.

2002-06-01

We have investigated Kaon-Nucleon (KN) interaction in a constituent quark model in the momentum range for the Kaon between 0 and 1 GeV/c in the laboratory frame. This study has been motivated by the fact that in an approach relying on a boson exchange mechanism the Bonn group was forced, in order to obtain good agreement with I = 0 s-wave phase shifts, to add the exchange of a short range fictitious repulsive scalar meson. This need for repulsion, whose range (∼ 0.2 fm) is smaller than the nucleon radius, clearly shows that the quark substructure of the nucleons and K + mesons cannot be neglected. The Kaon-Nucleon phase shifts are calculated in a quark potential model using the resonating group method (RGM). We have to cope with a five body problem with antisymmetrization with respect to the four ordinary quarks of the Kaon-Nucleon system. One requirement of our approach is that the quark-quark interaction must give a quite good description of the hadron spectra. One goal of the present work aims at determining the influence of a relativistic kinematics, in this constituent quark model, for the calculation of KN phase shifts. We have also investigated s, p, d, f, g waves KN elastic phase shifts and we have included a spin-orbit term in the quark-quark interaction. Then we have studied the influence of medium and long range exchange mechanism in the quark quark interaction on KN phase shifts. (author)

Nucleon and meson beams of the JINR phasotron for fundamental and applied investigations

International Nuclear Information System (INIS)

Abazov, V.M.; Andreev, G.A.; Bragin, A.N.

1990-01-01

The paper throughly describes the medical beam lines and reports the results obtained in measurement of the physical and dosimetric characteristics of high energy neutron, meson and proton beams obtained at the JINR phasotron in the last three years. It is pointed out that for the present intensity of the extracted proton beam of the JINR phasotron 2.0-2.5 μA the meson beam intensities 10 3 s- 1 (π + -mesons) and 3x10 7 s -1 (π - -mesons) have been achieved with a wide-angle magnetic lens. These values correspond to the designed parameters of the facility 'F' meson beams for the extracted proton beam intensity planned to be 25 μA. Besides, a beam of so-called 'surface μ-muons (energy about 4 MeV) with the intensity 10 4 s -1 has been obtained. The achieved meason beam intensities make the possibilities of the JINR phasotron as high as those of small meson factories with the equivalent extracted proton beam current 20-25 μA and ensures progress both in meson physics studies and in fulfilment of some applied tasks. 20 refs.; 7 figs.; 8 tabs

Description of a nucleon in nuclear matter using the chiral bag model

International Nuclear Information System (INIS)

Bunatyan, G.G.

1990-01-01

The chiral bag (cloudy bag) model, which contains an essentially nonlinear interaction of quarks with both the classical and quantum pion field, is extended for description of a nucleon in nuclear matter. The dependence on the density and temperature of the medium is studied. The pion field in nuclear matter differs considerably from the free field, and this leads to a modification of the nucleon bag. Increase of the density ρ and temperature T causes strengthening of the pion field and growth of its thermodynamic fluctuations. At sufficiently high densities ρ approx-gt ρ CB and temperatures T≥T cr this leads to instability of the three-quark nucleon bag. Under such conditions nuclear matter cannot be composed only of nucleons, and one should expect the appearance of a different, non-nucleon, phase. Estimates of the critical density and temperature are obtained: ρ CB ∼ (1.5-2)ρ 0 and T cr ∼ 200 MeV (where ρ 0 is the conventional nuclear density)

Chiral model for nucleon and delta

International Nuclear Information System (INIS)

Birse, M.C.; Banerjee, M.K.

1985-01-01

We propose a model of the nucleon and delta based on the idea that strong QCD forces on length scales approx.0.2--1 fm result in hidden chiral SU(2) x SU(2) symmetry and that there is a separation of roles between these forces which are also responsible for binding quarks in hadrons and the forces which produce absolute confinement. This leads us to study a linear sigma model describing the interactions of quarks, sigma mesons, and pions. We have solved this model in the semiclassical (mean-field) approximation for the hedgehog baryon state. We refer to this solution as a chiral soliton. In the semiclassical approximation the hedgehog state is a linear combination of N and Δ. We project this state onto states of good spin and isospin to calculate matrix elements of various operators in these states. Our results are in reasonable agreement with the observed properties of the nucleon. The mesonic contributions to g/sub A/ and sigma(πN) are about two to three times too large, suggesting the need for quantum corrections

Is nucleon deformed?

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

The production of {eta} and {omega} mesons in 3.5 GeV p+p interaction in HADES

Energy Technology Data Exchange (ETDEWEB)

Teilab, Khaled

2011-08-31

The study of meson production in proton-proton collisions in the energy range up to one GeV above the production threshold provides valuable information about the nature of the nucleon-nucleon interaction. Theoretical models describe the interaction between nucleons via the exchange of mesons. In such models, different mechanisms contribute to the production of the mesons in nucleon-nucleon collisions. The measurement of total and differential production cross sections provide information which can help in determining the magnitude of the various mechanisms. Moreover, such cross section information serves as an input to the transport calculations which describe e.g. the production of e{sup +}e{sup -} pairs in proton- and pion-induced reactions as well as in heavy ion collisions. In this thesis, the production of {omega} and {eta} mesons in proton-proton collisions at 3.5 GeV beam energy was studied using the High Acceptance DiElectron Spectrometer (HADES) installed at the Schwerionensynchrotron (SIS 18) at the Helmholtzzentrum fuer Schwerionenforschung in Darmstadt. About 80 000 {omega} mesons and 35 000 {eta} mesons were reconstructed. Total production cross sections of both mesons were determined. Furthermore, the collected statistics allowed for extracting angular distributions of both mesons as well as performing Dalitz plot studies. The {omega} and {eta} mesons were reconstructed via their decay into three pions ({pi}{sup +}{pi}{sup -}{pi}{sup 0}) in the exclusive reaction pp {yields} pp{pi}{sup +}{pi}{sup -}{pi}{sup 0}. The charged particles were identified via their characteristic energy loss, via the measurement of their time of flight and momentum, or using kinematics. The neutral pion was reconstructed using the missing mass method. A kinematic fit was applied to improve the resolution and to select events in which a {pi}{sup 0} was produced. The correction of measured yields for the effects of spectrometer acceptance was done as a function of four

Vector meson photoproduction with a linearly polarized beam

Science.gov (United States)

Mathieu, V.; Nys, J.; Fernández-Ramírez, C.; Jackura, A.; Pilloni, A.; Sherrill, N.; Szczepaniak, A. P.; Fox, G.; Joint Physics Analysis Center

2018-05-01

We propose a model based on Regge theory to describe photoproduction of light vector mesons. We fit the SLAC data and make predictions for the energy and momentum-transfer dependence of the spin-density matrix elements in photoproduction of ω , ρ0 and ϕ mesons at Eγ˜8.5 GeV , which are soon to be measured at Jefferson Lab.

A two component model describing nucleon structure functions in the low-x region

Energy Technology Data Exchange (ETDEWEB)

Bugaev, E.V. [Institute for Nuclear Research of the Russian Academy of Sciences, 7a, 60th October Anniversary prospect, Moscow 117312 (Russian Federation); Mangazeev, B.V. [Irkutsk State University, 1, Karl Marx Street, Irkutsk 664003 (Russian Federation)

2009-12-15

A two component model describing the electromagnetic nucleon structure functions in the low-x region, based on generalized vector dominance and color dipole approaches is briefly described. The model operates with the mesons of rho-family having the mass spectrum of the form m{sub n}{sup 2}=m{sub r}ho{sup 2}(1+2n) and takes into account the nondiagonal transitions in meson-nucleon scattering. The special cut-off factors are introduced in the model, to exclude the gamma-qq-bar-V transitions in the case of narrow qq-bar-pairs. For the color dipole part of the model the well known FKS-parameterization is used.

Chiral Quark-Meson model of N and DELTA with vector mesons

International Nuclear Information System (INIS)

Broniowski, W.; Banerjee, M.K.

1985-10-01

Vector mesons rho, A 1 and ω are introduced in the Chiral Quark-Meson Theory (CQMT) of N and Δ. We propose a new viewpoint for developing CQMT from QCD at the mean-field level. The SU(2) x SU(2) chiral Lagrangian incorporates universal coupling. Accordingly, rho is coupled to the conserved isospin current, A to the partially conserved axial-vector current (PCAC), and ω to the conserved baryon current. As a result the only parameter of the model not directly related to experiment is the quark-pion coupling constant. A fully self-consistent mean-field solution to the model is found for fields in the hedgehog ansatz. The vector mesons play a very important role in the system. They contribute significantly to the values of observables and produce a high-quality fit to many data. The classical stability of the system with respect to hedgehog excitations is analyzed through the use of the Quark-Meson RPA equations (QMRPA)

Quenching of weak interactions in nucleon matter

International Nuclear Information System (INIS)

Cowell, S.; Pandharipande, V.R.

2003-01-01

We have calculated the one-body Fermi and Gamow-Teller charge-current and vector and axial-vector neutral-current nuclear matrix elements in nucleon matter at densities of 0.08, 0.16, and 0.24 fm -3 and proton fractions ranging from 0.2 to 0.5. The correlated states for nucleon matter are obtained by operating on Fermi-gas states by a symmetrized product of pair correlation operators determined from variational calculations with the Argonne-v18 and Urbana-IX two- and three-nucleon interactions. The squares of the charge- current matrix elements are found to be quenched by 20-25 % by the short-range correlations in nucleon matter. Most of the quenching is due to spin-isospin correlations induced by the pion exchange interactions which change the isospins and spins of the nucleons. A large part of it can be related to the probability for a spin-up proton quasiparticle to be a bare spin-up/down proton/neutron. Within the interval considered, the charge-current matrix elements do not have significant dependence on the matter density, proton fraction, and magnitudes of nucleon momenta; however, they do depend on momentum transfer. The neutral-current matrix elements have a significant dependence on the proton fraction. We also calculate the matrix elements of the nuclear Hamiltonian in the same correlated basis. These provide relatively mild effective interactions that give the variational energies in the Hartree-Fock approximation. The calculated two-nucleon effective interaction describes the spin-isospin susceptibilities of nuclear and neutron matter fairly accurately. However terms greater than or equal to three-body terms are necessary to reproduce the compressibility. Realistic calculations of weak interaction rates in nucleon matter can presumably be carried out using the effective operators and interactions studied here. All presented results use the simple two-body cluster approximation to calculate the correlated basis matrix elements. This allows for a clear

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

Proceedings of the workshop on π, K, η-nucleon interactions

International Nuclear Information System (INIS)

1992-04-01

This workshop was held at the Research Center for Nuclear Physics, Osaka University, from February 18 to 20, 1991. This is the first attempt on this theme. The understanding of atomic nuclei as nucleon many body system is inseparable from the deeper understanding on the structures of nucleons and mesons and their interaction. It is considered that the physical experiment on medium energy atomic nuclei which is positively advanced at present in various places aims at the understanding of the hadron many body system of nucleons and mesons through the phenomena to which various degrees of freedom are related. This workshop is going to study on such hadron physics of atomic nuclei centering around the research including the elementary processes of various problems in the interactions of π and nuclei, K and nuclei and η and nuclei, taking the problems of the internal structures of hadrons themselves into the field of view. More than 50 people took part in the workshop, and also the reports from experiment side were carried out. In this book, 22 papers are collected. (K.I.)

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

Should the coupling constants be mass dependent in the relativistic mean field models

International Nuclear Information System (INIS)

Levai, P.; Lukacs, B.

1986-05-01

Mass dependent coupling constants are proposed for baryonic resonances in the relativistic mean field model, according to the mass splitting of the SU-6 multiplet. With this choice the negative effective masses are avoided and the system remains nucleon dominated with moderate antidelta abundance. (author)

Anomalous triple gauge couplings from $B$-meson and kaon observables

CERN Document Server

Bobeth, Christoph

2015-01-01

We consider the three CP-conserving dimension-6 operators that encode the leading new-physics effects in the triple gauge couplings. The contributions to the standard-model electromagnetic dipole and semi-leptonic vector and axial-vector interactions that arise from the insertions of these operators are calculated. We show that radiative and rare $B$-meson decays provide, under certain assumptions, constraints on two out of the three anomalous couplings that are competitive with the restrictions obtained from LEP II, Tevatron and LHC data. The constraints arising from the $Z \\to b \\bar b$ electroweak pseudo observables, $K \\to \\pi \

Meson production in nuclear collisions and the equation of state of hadronic matter

International Nuclear Information System (INIS)

Grosse, E.

1993-01-01

Whereas nuclear matter at saturation, i.e. at its ground state density [ρ o ≅ 1 nucleon per 6 fm 3 ] is realized in the center of nuclei, it is compressed to much higher density in neutron stars and during explosive stellar processes like novae and supernovae. The hard core repulsion in the nucleon-nucleon potential and also the Pauli principle counteract such a compression and the stiffness of the equation of state of this matter is determined by these two effects - at least up to a certain density. For very high density and temperature it is believed that the nucleons dissociate into a plasma of quarks and gluons. On the other hand there are detailed theoretical arguments and also experimental evidence shown here, that in the intermediate density range the equation of state is influenced by a different scenario. The conversion of nucleons into heavier baryons leads directly to an additional mass density and at the same time their different quantum numbers allow a higher particle number in a given volume of phase space. The heavy baryons in question are nucleon resonances (Δ,N*) and to smaller extent also hyperons; to conserve strangeness the formation of the latter is associated with the production of kaons whereas Δ's and N*'s are strongly coupled to the pions in the hadronic matter in the collision zone. (author)

Symmetry energy of nucleonic matter with tensor correlations

Science.gov (United States)

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.

Spin Density Matrix Elements in exclusive production of ω mesons at Hermes

Directory of Open Access Journals (Sweden)

Marianski B.

2014-03-01

Full Text Available Spin density matrix elements have been determined for exclusive ω meson production on hydrogen and deuterium targets, in the kinematic region of 1.0 < Q2 < 10.0 GeV2, 3.0 < W < 6.3 GeV and –t' < 0.2 GeV2. The data, from which SDMEs are determined, were accumulated with the HERMES forward spectrometer during the running period of 1996 to 2007 using the 27.6 GeV electron or positron beam of HERA. A sizable contribution of unnatural parity exchange amplitudes is found for exclusive ω meson production.

Dynamical coupled-channel analysis at EBAC. (Excited Baryon Analysis Center)

International Nuclear Information System (INIS)

Lee, T.-S.H.; Thomas Jefferson National Accelerator Facility, Newport News, VA

2008-01-01

In this contribution, the author reports on the dynamical coupled-channels analysis being pursued at the Excited Baryon Analysis Center (EBAC) of Jefferson Laboratory. EBAC was established in January 2006. Its objective is to extract the parameters associated with the excited states (N*) of the nucleon from the world data of meson production reactions, and to also develop theoretical interpretations of the extracted N* parameters

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)

Electromagnetic properties and sizes of new vector mesons within the three-triplet model

International Nuclear Information System (INIS)

Govorkov, A.B.

1976-01-01

The new vector mesons psi(3095) and psi'(3684) are treated by analogy with the ω- and PHI-mesons, respectively, within the scheme of three triplets of the integer charge quarks-sakations. Their decay into the lepton pairs is calculated in the model of nonrelativistic harmonic oscillator. It appears that sizes of the new mesons decrease, and the effective mass of constituent quarks increases as compared with the corresponding quantities of the usual mesons. Within the vector meson dominence model the relation between the width of the transition psi → ν+γ and photoproduction cross section on nucleons is established and the estimate for the former is 3 keV

Understanding the major uncertainties in the nuclear symmetry energy at suprasaturation densities

International Nuclear Information System (INIS)

Xu Chang; Li Baoan

2010-01-01

Within the interacting Fermi gas model for isospin asymmetric nuclear matter, effects of the in-medium three-body interaction and the two-body short-range tensor force owing to the ρ meson exchange, as well as the short-range nucleon correlation on the high-density behavior of the nuclear symmetry energy, are demonstrated respectively in a transparent way. Possible physics origins of the extremely uncertain nuclear symmetry energy at suprasaturation densities are discussed.

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

Three-Nucleon Forces and Triplet Pairing in Neutron Matter

Science.gov (United States)

Papakonstantinou, P.; Clark, J. W.

2017-12-01

The existence of superfluidity of the neutron component in the core of a neutron star, associated specifically with triplet P-wave pairing, is currently an open question that is central to interpretation of the observed cooling curves and other neutron-star observables. Ab initio theoretical calculations aimed at resolving this issue face unique challenges in the relevant high-density domain, which reaches beyond the saturation density of symmetrical nuclear matter. These issues include uncertainties in the three-nucleon (3N) interaction and in the effects of strong short-range correlations—and more generally of in-medium modification of nucleonic self-energies and interactions. A survey of existing solutions of the gap equations in the triplet channel demonstrates that the net impact on the gap magnitude of 3N forces, coupled channels, and mass renormalization shows extreme variation dependent on specific theoretical inputs, in some cases even pointing to the absence of a triplet gap, thus motivating a detailed analysis of competing effects within a well-controlled model. In the present study, we track the effects of the 3N force and in-medium modifications in the representative case of the ^3P_2 channel, based on the Argonne v_{18} two-nucleon (2N) interaction supplemented by 3N interactions of the Urbana IX family. Sensitivity of the results to the input interaction is clearly demonstrated. We point out consistency issues with respect to the simultaneous treatment of 3N forces and in-medium effects, which warrant further investigation. We consider this pilot study as the first step toward a systematic and comprehensive exploration of coupled-channel ^3P F_2 pairing using a broad range of 2N and 3N interactions from the current generation of refined semi-phenomenological models and models derived from chiral effective field theory.

Strange quark content in the nucleon and the strange quark vector current form factors

International Nuclear Information System (INIS)

Dubnicka, S.; Dubnickova, A.Z.

1996-12-01

A behaviour of the form factors of the nucleon matrix element of the strange quark vector current in the momentum range of the planned measurements in MIT/Bates and CEBAF is predicted theoretically without using any of the experimental information on the nucleon electromagnetic structure. The corresponding leading nonvanishing moments of the nucleon vector strangeness distribution are comparable with the values obtained by other authors in the framework of the method based on the vector meson pole fit of the isoscalar electromagnetic form factors of the nucleon. (author). 16 refs, 2 figs

Measurement of the production of K{sup +} mesons by protons in nuclei (1960); Mesure de la production des mesons K{sup +} par des protons dans les noyaux (1960)

Energy Technology Data Exchange (ETDEWEB)

Teiger, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1960-07-01

K{sup +} mesons produced by the internal proton beam of Saturne have been identified by means of scintillation and Cerenkov counters. The production cross sections are given per target nucleus measured at a laboratory angle of 35 deg. as well as the cross section relative to {pi}{sup +} mesons of the same momentum for: - incident protons of kinetic energy between 1.3 and 2.8 GeV, - targets of C, Cu and Pb, - K{sup +} produced with kinetic energies between 0.45 and 0.65 GeV. From these results we have tried to deduce the importance of indirect production by intermediate {pi} mesons with respect to direct production by proton-nucleon collisions. (author) [French] Au moyen de detecteurs a scintillations et a rayonnement Cerenkov, on a identifie les mesons lourds K{sup +} produits par les protons du faisceau interne de 'Saturne'. On donne les sections efficaces de production, par noyau cible, mesurees a 35 deg. dans le laboratoire, ainsi que les sections efficaces relatives par rapport aux mesons {pi}{sup +} de meme impulsion pour: - des protons incidents d'energie cinetique entre 1,3 GeV et 2,8 GeV, - des cibles de C, de Cu et de Pb, - des K{sup +} produits avec des energies cinetiques entre 0,45 et 0,65 GeV. De ces resultats, on a essaye de deduire l'importance de la production indirecte, par mesons {pi} intermediaires, par rapport a la production directe dans un choc proton-nucleon. (auteur)

The nucleon axial isoscalar coupling constant and the Bjorken sum rule

International Nuclear Information System (INIS)

Belyaev, V.M.; Ioffe, B.L.; Kogan, Ya.I.

1984-01-01

The nucleon coupling constant with the axial isoscalar current entering the Bjorken sum rule for the deep inelastic scattering of polarized electrons on a polarized target is calculated in nonperturbative QCD. The result, gsub(A)sup(s) approximately 0.5, is about a factor of two smaller as compared to that of the SU(6) symmetric quark model

Spin degrees of freedom in electron nucleon scattering in the resonance region

International Nuclear Information System (INIS)

Burkert, V.D.

1987-01-01

Some aspects of using polarized electrons and/or polarized targets in electron-nucleon scattering experiments are discussed. Polarization measurements can be used to extend the knowledge of nucleon form-factor measurements to higher Q 2 and are indispensable for a model-independent extraction of the helicity amplitudes of exclusive meson production. Measurements of polarization asymmetries may also help in revealing the excitation of weaker resonances

How sensitive are di-leptons from ρ mesons to the high baryon density region?

International Nuclear Information System (INIS)

Vogel, S.; Schmidt, K.; Santini, E.; Sturm, C.; Bleicher, M.; Petersen, H.; Aichelin, J.

2008-01-01

We show that the measurement of dileptons might provide only a restricted view into the most dense stages of heavy-ion reactions. Thus, possible studies of meson and baryon properties at high baryon densities, as, e.g., done at the GSI High Acceptance DiElectron Spectrometer (HADES) and envisioned for the Facility for Antiproton and Ion Research (FAIR) compressed baryonic matter experiments, might observe weaker effects than currently expected in certain approaches. We argue that the strong absorption of resonances in the high-baryon-density region of the heavy-ion collision masks information from the early hot and dense phase due to a strong increase of the total decay width because of collisional broadening. To obtain additional information, we also compare the currently used approaches to extract dileptons from transport simulations, i.e., shining, only vector mesons from final baryon resonance decays and instant emission of dileptons and find a strong sensitivity on the method employed in particular at FAIR and the CERN Super Proton Synchrotron energies. It is shown explicitly that a restriction to ρ meson (and therefore dilepton) production only in final-state baryon resonance decays provide a strong bias toward rather low baryon densities. The results presented are obtained from ultrarelativistic quantum molecular dynamics v2.3 calculations using the standard setup

Chaotic dynamics dependence on doping density in weakly coupled GaAs/AlAs superlattices

International Nuclear Information System (INIS)

Yang Gui; Zhang Fengying; Li Yuanhong; Li Yuqi

2012-01-01

A discrete sequential tunneling model is used for studying the influence of the doping density on the dynamical behaviors in weakly coupled GaAs/AlAs superlattices. Driven by the DC bias, the system exhibits self-sustained current oscillations induced by the period motion of the unstable electric field domain, and an electrical hysteresis in the loop of current density voltage curve is deduced. It is found that the hysteresis range strongly depends on the doping density, and the width of the hysteresis loop increases with increasing the doping density. By adding an external driving ac voltage, more complicated nonlinear behaviors are observed including quasiperiodicity, period-3, and the route of an inverse period-doubling to chaos when the driving frequency changes. (semiconductor physics)

Structure of the (0+,1+) mesons Bs0 and Bs1, and the strong coupling constant gBs0BK and gBs1B*K

International Nuclear Information System (INIS)

Wang, Z. G.

2008-01-01

In this article, we take the point of view that the bottomed (0 + ,1 + ) mesons B s0 and B s1 are the conventional bs meson and calculate the strong coupling constants g B s0 BK and g B s1 B*K with the light-cone QCD sum rules. The numerical values of strong coupling constants g B s1 B*K and g B s0 BK are very large and support the hadronic dressing mechanism. Just like the scalar mesons f 0 (980), a 0 (980), D s0 and axial-vector meson D s1 , the (0 + ,1 + ) bottomed mesons B s0 and B s1 may have small bs kernels of the typical bs meson size. The strong couplings to the hadronic channels (or the virtual mesons loops) may result in smaller masses than the conventional bs mesons in the potential quark models and enrich the pure bs states with other components.

Self-energies of octet and decuplet baryons due to the coupling to the baryon-meson continuum

Energy Technology Data Exchange (ETDEWEB)

Garcia-Tecocoatzi, H. [INFN, Sezione di Genova, Genova (Italy); Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Bijker, R. [Universidad Nacional Autonoma de Mexico, Instituto de Ciencias Nucleares, Mexico (Mexico); Ferretti, J. [Chinese Academy of Sciences, Institute of Theoretical Physics, Beijing (China); Dipartimento di Fisica, Universita di Roma Sapienza, Roma (Italy); INFN, Roma (Italy); Santopinto, E. [INFN, Sezione di Genova, Genova (Italy)

2017-06-15

We present an unquenched quark model calculation of the mass shifts of ground-state octet and decuplet baryons due to the coupling to the meson-baryon continuum. All ground-state baryons and pseudoscalar mesons are included in our calculation as intermediate states. The q anti q pair creation effects are taken explicitly into account through a microscopic, QCD-inspired, quark-antiquark pair creation mechanism. (orig.)

Role of nucleon resonance excitation in φ meson photoproduction

International Nuclear Information System (INIS)

Zhao, Q.; Didelez, J.P.; Guidal, M.; Saghai, B.

2000-01-01

The resonance effects are investigated in the φ meson photoproduction near threshold through a quark model approach with an effective Lagrangian. The diffractive contribution is consistently estimated by the t-channel Pomeron exchange. Another non-diffractive process, t-channel π 0 exchange is also included. The numerical result shows that the Pomeron exchange plays dominant role in the φ meson photoproduction, while the cross sections of the non-diffractive processes, i.e., s- and u-channel excitations, and t-channel π 0 exchange, are quite small. In the polarization observables, we find that large asymmetries are produced in the backward direction by the interferences from the s- and u-channel resonances, while in the forward direction, only very small asymmetries are generated. Meanwhile, we find that the effects from the π 0 exchange are generally negligible. (author)

Nucleon Mass from a Covariant Three-Quark Faddeev Equation

International Nuclear Information System (INIS)

Eichmann, G.; Alkofer, R.; Krassnigg, A.; Nicmorus, D.

2010-01-01

We report the first study of the nucleon where the full Poincare-covariant structure of the three-quark amplitude is implemented in the Faddeev equation. We employ an interaction kernel which is consistent with contemporary studies of meson properties and aspects of chiral symmetry and its dynamical breaking, thus yielding a comprehensive approach to hadron physics. The resulting current-mass evolution of the nucleon mass compares well with lattice data and deviates only by ∼5% from the quark-diquark result obtained in previous studies.

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

Possibility of ΛΛ pairing and its dependence on background density in a relativistic Hartree-Bogoliubov model

International Nuclear Information System (INIS)

Tanigawa, Tomonori; Matsuzaki, Masayuki; Chiba, Satoshi

2003-01-01

We calculate a ΛΛ pairing gap in binary mixed matter of nucleons and Λ hyperons within the relativistic Hartree-Bogoliubov model. Λ hyperons to be paired up are immersed in background nucleons in a normal state. The gap is calculated with a one-boson-exchange interaction obtained from a relativistic Lagrangian. It is found that at background density ρ N =2.5ρ 0 the ΛΛ pairing gap is very small, and that a denser background makes it rapidly suppressed. This result suggests a mechanism, specific to mixed matter dealt with relativistic models, of its dependence on the nucleon density. An effect of weaker ΛΛ attraction on the gap is also examined in connection with the revised information of the ΛΛ interaction

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

Method of taking into account meson and quark-gluon degrees of freedom in hadron-hadron interactions at low and intermediate energies. Application to NN scattering

International Nuclear Information System (INIS)

Safronov, A.N.

1983-01-01

A system of nonsingular integral equations is formulated for the calculation of hadron-hadron partial amplitudes in the low-and intermediate-energy range taking into account meson and quark-gluon degrees of freedom. The quark-gluon degrees of freedom are included in the framework of the composite-quark-bag model, and the meson degrees of freedom are treated by the methods of the relativistic quantum field theory. It is shown that including the quark-gluon degrees of freedom leads to suppression of meson exchange effects, mostly of heavy meson (rho, ω) exchanges. The method has been applied to the calculation of the 3 S 1 , 1 S 0 , 3 P 0 , 3 P 1 , and 1 P 1 phase shifts for the nucleon-nucleon scattering at the incident nucleon energies T=0-1050 MeV, as well as to the S-wave scattering lengths and effective radii

Pion-pion and pion-kaon interaction in the meson exchange picture

International Nuclear Information System (INIS)

Lohse, D.

1989-10-01

Following the general line of the Bonn NN-interaction, a model for pseudoscalar-pseudoscalar meson interaction has been constructed and applied consistently to ππ and Kπ scattering. The phases can be reproduced with vector meson t- and s-channel exchange up to 1 GeV. The bare masses of the vector mesons turn out to be in the range of 1.1 GeV, depending on the form factor. We use a coupled channel formalism, which is crucial to explain the S * (975) resonance as a bound anti KK state. Beyond 1 GeV the data require a pseudoscalar-pseudoscalar coupling to a scalar octet (J P =0 + ) to fit the s-wave phases in the isospin-0 π and isospin-1/2 Kπ channels. We apply both scalar coupling and derivative coupling. The latter avoids introducing additional degrees of freedom and produces an acceptable fit to the J=0 phase shift data. (orig.) [de

Strangeness in the nucleon on the light-cone

International Nuclear Information System (INIS)

Malheiro, Manuel; Melnitchouk, Wally

1999-01-01

Strange matrix elements of the nucleon are calculated within the light-cone formulation of the meson cloud model. The Q 2 dependence of the strange vector form factors is computed, and the strangeness radius and magnetic moment extracted, both of which are found to be very small. The strange magnetic moment μ S is seen to change sign once the spurious form factors arising from the violation of rotational invariance are subtracted. The resulting μ S is small and slightly positive, in agreement with the trend of the recent data from the SAMPLE experiment. Within the same framework one finds a small but non-zero excess of the antistrange distribution over the strange at large x. (author)

Radial Dependence of the Nucleon Effective Mass in B sup 1 sup 0

CERN Document Server

Bever, L J D; Hicks, R; Jager, K D; Kelly, J; Lapikas, L; Miskimen, R; Neck, D V; Peterson, G; Steenhoven, G; Vries, H D

1998-01-01

The dynamic properties of the atomic nucleus depend strongly on correlations between the nucleons. We present a combined analysis of inelastic electron-scattering data and electron-induced proton knockout measurements in an effort to obtain phenomenological information on nucleon-nucleon correlations. Our results indicate that the ration of radial wave functions extracted from precise B sup 1 sup 0 (e,e') and B sup 1 sup 0 (e, e'p) measurements evolve from an interior depression for small Em, characteristic of short-range correlations, to a surface-peaked enhancement for larger Em, characteristic of long-range correlations. This observation can be interpreted in terms of the nucleon effective mass.

High strangeness production in antiproton annihilation at rest on few nucleon systems as a possible signature of quark deconfinement or QGP occurrence

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

Prospects for meson spectroscopy studies with anti P's at the AGS

International Nuclear Information System (INIS)

Dover, C.B.

1987-01-01

This paper contains viewgraphs on studies of meson spectroscopy. Investigated are the pion inclusive spectrum of proton-antiproton interactions, the spectrum of nucleon-antinucleon interactions, pion missing mass spectra and mechanisms for photon-photon interactions

Boson-exchange nucleon-nucleon potential and nuclear structure

International Nuclear Information System (INIS)

Grange, Pierre.

1976-01-01

A fully momentum-dependent one-boson-exchange potential is derived which takes into account the mesons, π, eta, sigma, rho, ω and phi. Scattering bound states and nuclear matter properties are studied in momentum space. The use of such potential is shown to be as easy as the use of more simple phenomenological interactions. In nuclear matter the formalism of Bethe-Goldstone is chosen to compute the binding energy versus density in the approximation of two-body and three-body correlations. The three-body correlated wave function obtained is then used [fr

Low-energy analysis of the nucleon electromagnetic form factors[12.39.Fe; 13.40.Gp; 14.20.Dh; Nucleon electromagnetic form factors; Chiral perturbation theory

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}.

Pion-nucleon form factor in the Chew-Low theory

International Nuclear Information System (INIS)

Ernst, D.J.; Johnson, M.B.

1978-01-01

We find a solution to the static Chew-Low theory of pion-nucleon scattering, avoiding the ''one-meson approximation.'' Our basic equation is crossing symmetric and may be solved for phase shifts delta (p) by standard numerical techniques, upon specifying a form factor v (p) and a set of inelasticities. With v (p) = exp(-p 2 /30) we reproduce experimental delta (p) for p/sub L/ < or = 1.2 GeV/c in the (3,3) state; in the (1,3) states and (3,1) states delta (p) compare well on the average but in the (1,1) state delta (p) have opposite signs. We show the importance of crossing symmetry and the coupling to inelastic channels, and we discuss the possibility of determining v (p) directly from elastic scattering by an inverse scattering formula

Medium dependence of vector meson properties in heavy ion collisions

International Nuclear Information System (INIS)

Faessler, Amand; Fuchs, Christian

2007-01-01

Heavy ion collisions produce dense and hot nuclear matter. Dileptons give information about this hot and dense phase. The dileptons are produced by vector mesons. Theoretical calculation of dilepton production in the DLS (Berkeley), the HADES (GSI) experiments and the CERES, HELIOS and NA60 data from CERN give information about possible modifications of the vector meson properties in hot and dense nuclear matter. Here the description in relativistic quantum molecular dynamics of heavy ion collisions and dilepton production are presented and compared with data. (authors) Key words: heavy ion collisions; dense and hot nuclear matter; dileptons; medium dependence

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.)

Equivalence of meson scattering amplitudes in strong coupling lattice and flat space string theory

Directory of Open Access Journals (Sweden)

Adi Armoni

2018-03-01

Full Text Available We consider meson scattering in the framework of the lattice strong coupling expansion. In particular we derive an expression for the 4-point function of meson operators in the planar limit of scalar Chromodynamics. Interestingly, in the naive continuum limit the expression coincides with an independently known result, that of the worldline formalism. Moreover, it was argued by Makeenko and Olesen that (assuming confinement the resulting scattering amplitude in momentum space is the celebrated expression proposed by Veneziano several decades ago. This motivates us to also use holography in order to argue that the continuum expression for the scattering amplitude is related to the result obtained from flat space string theory. Our results hint that at strong coupling and large-Nc the naive continuum limit of the lattice formalism can be related to a flat space string theory.

Equivalence of meson scattering amplitudes in strong coupling lattice and flat space string theory

Science.gov (United States)

Armoni, Adi; Ireson, Edwin; Vadacchino, Davide

2018-03-01

We consider meson scattering in the framework of the lattice strong coupling expansion. In particular we derive an expression for the 4-point function of meson operators in the planar limit of scalar Chromodynamics. Interestingly, in the naive continuum limit the expression coincides with an independently known result, that of the worldline formalism. Moreover, it was argued by Makeenko and Olesen that (assuming confinement) the resulting scattering amplitude in momentum space is the celebrated expression proposed by Veneziano several decades ago. This motivates us to also use holography in order to argue that the continuum expression for the scattering amplitude is related to the result obtained from flat space string theory. Our results hint that at strong coupling and large-Nc the naive continuum limit of the lattice formalism can be related to a flat space string theory.

Nucleon axial coupling from Lattice QCD

Science.gov (United States)

Cheng Chang, Chia; Nicholson, Amy; Rinaldi, Enrico; Berkowitz, Evan; Garron, Nicolas; Brantley, David; Monge-Camacho, Henry; Monahan, Chris; Bouchard, Chris; Clark, M. A.; Joó, Bálint; Kurth, Thorsten; Orginos, Kostas; Vranas, Pavlos; Walker-Loud, André

2018-03-01

We present state-of-the-art results from a lattice QCD calculation of the nucleon axial coupling, gA, using Möbius Domain-Wall fermions solved on the dynamical Nf = 2 + 1 + 1 HISQ ensembles after they are smeared using the gradient-flow algorithm. Relevant three-point correlation functions are calculated using a method inspired by the Feynman-Hellmann theorem, and demonstrate significant improvement in signal for fixed stochastic samples. The calculation is performed at five pion masses of mπ {400, 350, 310, 220, 130} MeV, three lattice spacings of a {0.15, 0.12, 0.09} fm, and we do a dedicated volume study with mπL {3.22, 4.29, 5.36}. Control over all relevant sources of systematic uncertainty are demonstrated and quantified. We achieve a preliminary value of gA = 1.285(17), with a relative uncertainty of 1.33%.

Chiral pion dynamics for spherical nucleon bags

International Nuclear Information System (INIS)

Vento, V.; Rho, M.; Nyman, E.M.; Jun, J.H.; Brown, G.E.; CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette

1980-01-01

A chirally symmetric quark-bag model for the nucleon is obtained by introducing an explicit, classical, pion field exterior to the bag. The coupling at the bag surface is determined by the requirement of a conserved axial-vector current. The pion field satisfies equations of motion corresponding to the non-linear sigma-model. We study on this paper the simplified case where the bag and the pion field are spherically symmetric. Corrections due to gluon exchange between the quarks are ignored along with other interactions which split the N- and Δ-masses. The equations of motion for the pion field are solved and we find a substantial pion pressure at the bag surface, along with an attractive contribution to the nucleon self-energy. The total energy of the system, bag plus meson cloud, turns out to be approximately Msub(n)c 2 for a wide range of bag radii, from 1.5 fm down to about 0.5 fm. Introduction of a form factor for the pion would extend the range of possible radii to even smaller values. We propose that the bag with the smallest allowed radius be identified with the 'little bag' discussed before. One surprising result of the paper is that as long as one restricts to spherically symmetric bags, restoring chiral symmetry to the bag model makes the axial-vector current coupling constant gsub(A) to be always too large compared with the experimental value for any bag radius, suggesting a deviation from spherical symmetry for the intrinsic bag wave functions of the 'ground-state' hadrons. (orig.)

Nucleon-nucleon scattering in the functional quantum theory of the non-linear spinor field

International Nuclear Information System (INIS)

Philipp, W.

1975-01-01

The nucleon-nucleon and nucleon-antinucleon scattering cross sections are calculated in the frame of the functional quantum field theory by means of two different approximation methods: averaging by integration of indefinite integrals and pulse averaging. The results for nucleon-nucleon scattering are compared with experimental data, with calculations using a modified functional scalar product and with results in first order perturbation theory (V-A-coupling). As for elastic nucleon-antinucleon scattering, the S matrix is investigated for crossing symmetry. Scattering of 'nucleons' of different mass results in different cross sections even in the lowest-order approximation. (BJ) [de

Four-nucleon system with Δ-isobar excitation

International Nuclear Information System (INIS)

Deltuva, A.; Fonseca, A.C.; Sauer, P.U.

2008-01-01

The four-nucleon bound state and scattering below three-body breakup threshold are described based on the realistic coupled-channel potential CD Bonn+Δ which allows the excitation of a single nucleon to a Δ isobar. The Coulomb repulsion between protons is included. In the four-nucleon system the two-baryon coupled-channel potential yields effective two-, three- and four-nucleon forces, mediated by the Δ isobar and consistent with each other and with the underlying two-nucleon force. The effect of the four-nucleon force on the studied observables is much smaller than the effect of the three-nucleon force. The inclusion of the Δ isobar is unable to resolve the existing discrepancies with the experimental data

One-Boson Approach to Dilepton Production in Nucleon-Nucleon Collisions.

Science.gov (United States)

Haglin, Kevin Lee

1990-01-01

We calculate energy dependent nucleon-nucleon total elastic cross sections and invariant mass dependent electron-positron pair production differential cross sections for the processes pp to pp, np to np and pp to ppe ^+e^-, pn to pne^+e ^- at laboratory kinetic energies in the 1-5 GeV range. These calculations will be based on relativistic quantum field theory in the one-boson-exchange (pi,rho,omega,sigma,delta, eta) approximation to the nucleon-nucleon scattering problem. There are several independent Feynman diagrams for each process--twenty-five for the case np to npe^+e^ - and forty-eight for the case pp to ppe^+e^- --which, for evaluation, require taking the trace of as many as ten gamma matrices and evaluating an angular integral of a quotient of polynomial functions of initial and final energies, particle masses, coupling constants and so on. These mathematical operations are carried out with the aid of the following algebraic manipulators: for the trace operations we use REDUCE 3.3 on the VAX at the ACS facility and for testing the angular integration algorithms we use MAPLE on the Cray-2 at the Minnesota Supercomputer Institute. Finally, we use Cray-2 Fortran for the resulting numerical substitutions. Gauge invariance is strictly observed while including strong and electromagnetic form factors. The numerical results for these calculations are compared with existing data from the Particle Data Group Booklet and compared with recently released data from the Dilepton Spectrometer (DLS) at the Bevalac of proton on Beryllium. For the latter comparison, the spectrometer's finite acceptance function is introduced before a rapidity and transverse momentum integration.

Evidence for the Production of Neutral Mesons by Photons

CERN Document Server

Steinberger, J; Panofsky, Wolfgang Kurt Hermann

1950-01-01

In the bombardment of nuclei by 330-Mev x-rays, multiple gamma-rays are emitted. From their angular correlation it is deduced that they are emitted in pairs in the disintegration of neutral particles moving with relativistic velocities and therefore of intermediate mass. The neutral mesons are produced with cross sections similar to those for the charged mesons and with an angular distribution peaked more in the forward direction. The production cross section in hydrogen and the production cross section per nucleon in C and Be are comparable.

Upper limits on beauty meson production in π- collisions at 280 GeV/c

International Nuclear Information System (INIS)

Badier, J.; Bourotte, J.; Mine, P.; Vanderhaghen, R.; Weisz, S.; Boucrot, J.; Callot, O.; Decamp, D.; Karyotakis, Y.; Lefrancois, J.; Crozon, M.; Delpierre, P.; Leray, T.; Maillard, J.; Tilquin, A.; Valentin, J.

1983-01-01

From events with two like-sign muons, or with three or four muons, observed in the NA3 spectrometer with 280 GeV/c incoming π - beam, we deduce upper limits on the production of beauty meson pairs Banti B. We use the leptonic branching ratios of B meson measured at CESR storage rings, and assume that no nuclear effects occur in the platinum target. We find sigma(Banti B) < 2 nb/nucleon for centrally produced Banti B pairs, and sigma(Banti B) < 10 nb/nucleon for a diffractive production. These values are one order of magnitude lower than previously published limits. As a consequence, the psipsi events observed in our experiment cannot come from Banti B decays. (orig.)

Formation and disintegration of high-density nuclear matter in heavy-ion collisions

International Nuclear Information System (INIS)

Kitazoe, Yasuhiro; Matsuoka, Kazuo; Sano, Mitsuo

1976-01-01

The formation of high-density nuclear matter which may be expected to be attained in high-energy heavy-ion collisions and the subsequent disintegration of dense matter are investigated by means of the hydrodynamics. Head-on collisions of identical nuclei are considered in the nonrelativistic approximation. The compressed density cannot exceed 4 times of the normal one so long as the freedom of only nucleons is considered, and can become higher than 4 times when other freedoms such as the productions of mesons and also nucleon isobars are additionally taken into account. The angular distributions for ejected particles predominate both forwards and backwards at low collision energies, corresponding to the formation of nuclear density less than 2 times of the normal density and become isotropic at the point of 2 times of the normal one. As the collision energy increases further, lateral ejection is intensified gradually. (auth.)

Dynamical isospin effects in nucleon-induced reactions

International Nuclear Information System (INIS)

Ou Li; Li Zhuxia; Wu Xizhen

2008-01-01

The isospin effects in proton-induced reactions on isotopes of 112-132 Sn and the corresponding β-stable isobars are studied by means of the improved quantum molecular dynamics model and some sensitive probes for the density dependence of the symmetry energy at subnormal densities are proposed. The beam energy range is chosen to be 100-300 MeV. Our study shows that the system size dependence of the reaction cross sections for p+ 112-132 Sn deviates from the Carlson's empirical expression obtained by fitting the reaction cross sections for proton on nuclei along the β-stability line and sensitively depends on the stiffness of the symmetry energy. We also find that the angular distribution of elastic scattering for p+ 132 Sn at large impact parameters is very sensitive to the density dependence of the symmetry energy, which is uniquely due to the effect of the symmetry potential with no mixture of the effect from the isospin dependence of the nucleon-nucleon cross sections. The isospin effects in neutron-induced reactions are also studied and it is found that the effects are just opposite to that in proton-induced reactions. We find that the difference between the peaks of the angular distributions of elastic scattering for p+ 132 Sn and n+ 132 Sn at E p,n =100 MeV and b=7.5 fm is positive for soft symmetry energy U sym sf and negative for super-stiff symmetry energy U sym nlin and close to zero for linear density dependent symmetry energy U sym lin , which seems very useful for constraining the density dependence of the symmetry energy at subnormal densities

Exclusive Backward-Angle Omega Meson Electroproduction

Energy Technology Data Exchange (ETDEWEB)

Wenliang, Li [Univ. of Regina, Regina, SK (Canada)

2017-10-01

Exclusive meson electroproduction at different squared four-momenta of the exchanged virtual photon, Q² , and at different four-momentum transfers, t and u, can be used to probe QCD's transition from hadronic degrees of freedom at the long distance scale to quark-gluon degrees of freedom at the short distance scale. Backward-angle meson electroproduction was previously ignored, but is anticipated to offer complimentary information to conventional forward-angle meson electroproduction studies on nucleon structure. This work is a pioneering study of backward-angle ω cross sections through the exclusive ¹H(e, e'p)ω reaction using the missing mass reconstruction technique. The extracted cross sections are separated into the transverse (T), longitudinal (L), and LT, TT interference terms. The analyzed data were part of experiment E01-004 (Fπ-2), which used 2.6-5.2 GeV electron beams and HMS+SOS spectrometers in Jefferson Lab Hall C. The primary objective was to detect coincidence π in the forward-angle, where the backward-angle omega events were fortuitously detected. The experiment has central Q² values of 1.60 and 2.45 GeV² , at W = 2.21 GeV. There was significant coverage in phi and epsilon, which allowed separation of σ_T,L,LT,TT . The data set has a unique u coverage of -u ~ 0, which corresponds to -t > 4 GeV² . The separated σ_T result suggest a flat ~ 1/Q^1.33±1.21 dependence, whereas sigma_L seems to hold a stronger 1/Q^9.43±6.28 dependence. The σL/σ_T ratio indicate σ_T dominance at Q² = 2.45 GeV² at the ~90% confidence level. After translating the results into the -t space of the published CLAS data, our data show evidence of a backward-angle omega electroproduction peak at both Q² settings. Previously, this phenomenon showing both forward and backward-angle peaks was only observed in the meson

On the vector meson dominate hypothesis and the RA = σLA/σTA value in electron-nucleus deep inelastic scattering

International Nuclear Information System (INIS)

Peng Hongan; Liu Lianshou

1986-01-01

It is argued that the longitudinal part of space-like photon in its Breit frame is unable to transform into vector meson. Starting from this argument and adding a small amount of diquark component into the nucleon structure functions in nuclei, the A dependence of the R A = σ L A /σ T A value observed in electron nucleus DIS by the SLAC Group is explained

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

Microscopic nuclear structure calculations with modern meson-exchange potentials

International Nuclear Information System (INIS)

Hjort-Jensen, M.; Osnes, E.; Muether, H.; Schmid, K.W.; Kuo, T.T.S.

1990-07-01

The report presents the results of microscopic nuclear shell-model calculations using three different nucleon-nucleon potentials. These are the phenomenological Reid-Soft-Core potential and the meson-exchange potentials of the Paris and the Bonn groups. It is found that the Bonn potential yields sd-shell matrix elements which are more attractive than those obtained with the Reid or the Paris potentials. The harmonic-oscillator matrix elements of the Bonn potential are also in better agreement with the empirically derived matrix elements of Wildenthal. The implications are discussed. 27 refs., 4 figs., 1 tab

Meson theory of charge-dependent nuclear forces. Chapter 10

International Nuclear Information System (INIS)

Henley, E.M.; Miller, G.A.

1979-01-01

Although the charge dependence is a small effect it is a useful probe for nuclear structure and forces details. The authors are primarily concerned with the short-range meson-theoretic origin of these forces. They discuss recent experimental and theoretical advances and give applications and possible tests of the theory. (D.H.)

Dilepton production in nucleon–nucleon collisions around 1 GeV ...

Indian Academy of Sciences (India)

We present a fully relativistic and gauge invariant framework for calculating the cross-sections of dilepton production in nucleon–nucleon ( ) collisions which is based on the meson-exchange approximation for the scattering amplitudes. Predictions of our model are compared with those of other covariant models that ...

Method of taking into account the meson and quark-gluon degrees of freedom in hadron-hadron interactions at low and intermediate energies. Application to NN scattering

International Nuclear Information System (INIS)

Safronov, A.N.

1983-01-01

A system of nonsingular integral equations is formulated for calculation of the partial-wave amplitudes of hadron-hadron scattering in the region of low and intermediate energies with allowance for the meson and quark-gluon degrees of freedom. The quark-gluon degrees of freedom are taken into account in the framework of the model of composite quark bags, and the meson degrees of freedom by the methods of relativistic quantum field theory. It is shown that inclusion of the quark-gluon degrees of freedom leads to suppression of meson exchange effects, for the most part exchanges of heavy mesons (rho,ω). The method is applied to the calculation of the 3 S 1 , 1 S 0 , 3 P 0 , 3 P 1 , and 1 P 1 phase shifts of nucleon-nucleon scattering in the range of incident-nucleon energies T = 0--1050 MeV, as well as the S-wave scattering lengths and effective ranges

Vector mesons in strongly interacting matter

Indian Academy of Sciences (India)

Results on the light vector mesons ρ, , and , are summarized and compared. Almost all experiments report a softening of the spectral functions with increases in width depending on the density and temperature of the hadronic environment. No evidence for mass shifts is found in majority of the experiments. Remaining ...

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

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.)

Picture book of nucleon--nucleon scattering: amplitudes, models, double- and triple-spin observables

International Nuclear Information System (INIS)

Field, R.D.; Stevens, P.R.

1975-01-01

A comprehensive study of nucleon-nucleon scattering is presented with particular emphasis on the underlying amplitude structure. The five complex NN amplitudes are determined as a function of energy and momentum transfer from existing pp, anti pp, and np elastic scattering data and np and anti pp CHEX data. Some constraints determined from meson-baryon fits are imposed. The resulting amplitudes are used to make predictions of forthcoming double- and triple-spin measurements, and are also compared with the model amplitudes of Kane and Seidl. In addition, the usefulness of transversity amplitudes in NN scattering is discussed, the status of our present knowledge concerning them is examined, and model predictions of these amplitudes are displayed. The paper is presented in a ''picture book'' form so that the reader can get a good overview of NN scattering by studying the figures and reading the tables and figure captions

High statistics inclusive φ meson production at SPS energies

International Nuclear Information System (INIS)

Dijkstra, H.; Belau, E.

1986-01-01

Inclusive φ meson production has been measured for 100 GeV/c and 200 GeV/c incident π - , anti p and K - , and for 120 GeV/c and 200 GeV/c incident π + , p and K + , using a Be target. A total of 630,000 φ mesons has been recorded in the kinematic range 0 F F and dσ/dp T 2 . The longitudinal momentum distributions show that the strange valence quarks of the incident K mesons play an important role in φ meson production, even at small x F . The decay angular distribution of the φ meson is evaluated in the Gottfried-Jackson frame and is expressed in the elements of the density matrix. There is a small but significant cos 2 θ GJ dependence for small p T , which decreases for increasing p T . (Auth.)

A new model for nuclear matter

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

The different values obtained for nuclear radii from electromagnetic interactions as compared with specifically nuclear interactions suggested a model of nuclear matter in which the meson field is supposed to condense into an incompressible fluid and the nucleonic sources are confined to its interior by a strong interaction between the sources and the fluid as a whole. The sources are also coupled to spin and charge fluctuations in the fluid, whose exchange leads to further internucleonic forces. It is necessary to postulate that the fluid have a comparatively low density; as a result rotational levels of the fluid are high, leading to a small probability of exchange of angular momentum (and charge coupled to it) with the sources. The values of the anomalous electrical interactions of nucleons deduced are in rough agreement with the facts. The nuclear structure indicated is a shell model embedded in the mesic fluid whose oscillations, strongly coupled to the nucleons, give rise to the collective features of nuclear structure as in the theory of Bohr and Mottelson. It is suggested that this picture of the mesic field may indicate where to look for solutions of the meson field equations. (author). 9 refs

Conflicting Coupling of Unpaired Nucleons and the Structure of Collective Bands in Odd-Odd Nuclei

International Nuclear Information System (INIS)

Levon, A.I.; Pasternak, A.A.

2011-01-01

The conflicting coupling of unpaired nucleons in odd-odd nuclei is discussed. A very simple explanation is suggested for the damping of the energy spacing of the lowest levels in the rotational bands in odd-odd nuclei with the 'conflicting' coupling of an odd proton and an odd neutron comparative to those of the bands based on the state of a strongly coupled particle in the neighboring odd nucleus entering the 'conflicting' configuration.

Probing the nuclear medium with the K+ meson

International Nuclear Information System (INIS)

Chrien, R.E.

1995-01-01

Elastic differential cross sections for K + mesons scattered from targets of carbon and 6 Li have been measured at an incident momentum of 715 MeV/c. The ratios of scattering cross sections from these targets are not predicted by theory, and are consistent with earlier suggestions that the K + -nucleon interaction is modified in the nuclear medium

and electro-production of mesons with arbitrary spins

Indian Academy of Sciences (India)

carried out by straightforward methods'. These formulae apply directly for photo- production of other pseudoscalar mesons like η. In the case of the isovector pion, an earlier isospin analysis by Watson [13] was made use of to express each one of these amplitudes Fi(i = 1–4) in terms of three independent nucleon isospin ...

Classical model for nuclear collisions including the meson degree of freedom

International Nuclear Information System (INIS)

Babinet, R.; Kunz, J.; Mosel, U.; Wilets, L.

1980-01-01

Many different approaches have been taken to describe high energy heavy ion collisions. L. Wilets et al proposed a classical treatment of the problem. In his model non-relativistic nucleons move on classical trajectories. However, the Pauli-principle is simulated by a momentum dependent potential acting between the nucleons. This model is extended in two ways. The nucleons are coupled to a pionfield, which enables us to describe inelastic processes. Nucleons and pionfiled are treated completely relativistically, this also assures Lorentz invariance. We aim at a set of classical equations of motion describing the interacting system of nucleons and pionfield. These classical equations should have a quantum mechanical basis. Further, they should contain such fundamental properties of the pion-nucleon system as the Δ(3,3)-resonance, at least in a qualitative manner. (orig./FKS)

Nuclear ``pasta'' phase within density dependent hadronic models

Science.gov (United States)

Avancini, S. S.; Brito, L.; Marinelli, J. R.; Menezes, D. P.; de Moraes, M. M. W.; Providência, C.; Santos, A. M.

2009-03-01

In the present paper, we investigate the onset of the “pasta” phase with different parametrizations of the density dependent hadronic model and compare the results with one of the usual parametrizations of the nonlinear Walecka model. The influence of the scalar-isovector virtual δ meson is shown. At zero temperature, two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature, only the coexistence phases method is used. npe matter with fixed proton fractions and in β equilibrium are studied. We compare our results with restrictions imposed on the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations.

Nuclear 'pasta' phase within density dependent hadronic models

International Nuclear Information System (INIS)

Avancini, S. S.; Marinelli, J. R.; Menezes, D. P.; Moraes, M. M. W. de; Brito, L.; Providencia, C.; Santos, A. M.

2009-01-01

In the present paper, we investigate the onset of the 'pasta' phase with different parametrizations of the density dependent hadronic model and compare the results with one of the usual parametrizations of the nonlinear Walecka model. The influence of the scalar-isovector virtual δ meson is shown. At zero temperature, two different methods are used, one based on coexistent phases and the other on the Thomas-Fermi approximation. At finite temperature, only the coexistence phases method is used. npe matter with fixed proton fractions and in β equilibrium are studied. We compare our results with restrictions imposed on the values of the density and pressure at the inner edge of the crust, obtained from observations of the Vela pulsar and recent isospin diffusion data from heavy-ion reactions, and with predictions from spinodal calculations

Meson production near threshold: physics implications and new technical challenges

Energy Technology Data Exchange (ETDEWEB)

Meyer, H.O. [Indiana Univ., Bloomington, IN (United States). Dept. of Physics

1995-02-01

Recently, the study of pion production in few-nucleon systems has been advanced considerably, mainly due to experiments using internal targets in stored, cooled beams. Experimental progress has inspired theoretical insights: from measurements close to threshold we have learned that an enhancement of the axial charge caused by heavy-meson exchange significantly contributes to pion production. The study of the production of pions, as well as heavier mesons, with stored polarized beams and polarized internal targets is likely to heave important consequences for our understanding of the nuclear force. (author). 42 refs, 11 figs.

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)

Measurement of the centrality dependence of $J/{\\psi}$ yields and observation of Z production in lead-lead collisions with the ATLAS detector at the LHC

CERN Document Server

Aad, G.; Abdallah, J.; Abdelalim, A.A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B.S.; Ackers, M.; Adams, D.L.; Addy, T.N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J.A.; Aharrouche, M.; Ahlen, S.P.; Ahles, F.; Ahmad, A.; Ahsan, M.; Aielli, G.; Akdogan, T.; Akesson, T.P.A.; Akimoto, G.; Akimov, A.V.; Alam, M.S.; Alam, M.A.; Albrand, S.; Aleksa, M.; Aleksandrov, I.N.; Aleppo, M.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P.P.; Allwood-Spiers, S.E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, J.; Alviggi, M.G.; Amako, K.; Amaral, P.; Amelung, C.; Ammosov, V.V.; Amorim, A.; Amoros, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C.F.; Anderson, K.J.; Andreazza, A.; Andrei, V.; Andrieux, M-L.; Anduaga, X.S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Anulli, F.; Aoun, S.; Aperio Bella, L.; Apolle, R.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A.T.H.; Archambault, J.P.; Arfaoui, S.; Arguin, J-F.; Arik, E.; Arik, M.; Armbruster, A.J.; Arms, K.E.; Armstrong, S.R.; Arnaez, O.; Arnault, C.; Artamonov, A.; Artoni, G.; Arutinov, D.; Asai, S.; Asfandiyarov, R.; Ask, S.; Asman, B.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M.A.; Baccaglioni, G.; Bacci, C.; Bach, A.M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Badescu, E.; Bagnaia, P.; Bahinipati, S.; Bai, Y.; Bailey, D.C.; Bain, T.; Baines, J.T.; Baker, O.K.; Baker, M.D.; Baker, S.; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Bansil, H.S.; Barak, L.; Baranov, S.P.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E.L.; Barberis, D.; Barbero, M.; Bardin, D.Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B.M.; Barnett, R.M.; Baroncelli, A.; Barr, A.J.; Barreiro, F.; Barreiro Guimaraes da Costa, J.; Barrillon, P.; Bartoldus, R.; Barton, A.E.; Bartsch, D.; Bates, R.L.; Batkova, L.; Batley, J.R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H.S.; Beare, B.; Beau, T.; Beauchemin, P.H.; Beccherle, R.; Bechtle, P.; Beck, H.P.; Beckingham, M.; Becks, K.H.; Beddall, A.J.; Beddall, A.; Bednyakov, V.A.; Bee, C.; Begel, M.; Behar Harpaz, S.; Behera, P.K.; Beimforde, M.; Belanger-Champagne, C.; Bell, P.J.; Bell, W.H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, G.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B.H.; Benekos, N.; Benhammou, Y.; Benjamin, D.P.; Benoit, M.; Bensinger, J.R.; Benslama, K.; Bentvelsen, S.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Berglund, E.; Beringer, J.; Bernardet, K.; Bernat, P.; Bernhard, R.; Bernius, C.; Berry, T.; Bertin, A.; Bertinelli, F.; Bertolucci, F.; Besana, M.I.; Besson, N.; Bethke, S.; Bhimji, W.; Bianchi, R.M.; Bianco, M.; Biebel, O.; Biesiada, J.; Biglietti, M.; Bilokon, H.; Bindi, M.; Bingul, A.; Bini, C.; Biscarat, C.; Bitenc, U.; Black, K.M.; Blair, R.E.; Blanchard, J.B.; Blanchot, G.; Blocker, C.; Blocki, J.; Blondel, A.; Blum, W.; Blumenschein, U.; Bobbink, G.J.; Bobrovnikov, V.B.; Bocci, A.; Bock, R.; Boddy, C.R.; Boehler, M.; Boek, J.; Boelaert, N.; Boser, S.; Bogaerts, J.A.; Bogdanchikov, A.; Bogouch, A.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Bona, M.; Boonekamp, M.; Boorman, G.; Booth, C.N.; Booth, P.; Booth, J.R.A.; Bordoni, S.; Borer, C.; Borisov, A.; Borissov, G.; Borjanovic, I.; Borroni, S.; Bos, K.; Boscherini, D.; Bosman, M.; Boterenbrood, H.; Botterill, D.; Bouchami, J.; Boudreau, J.; Bouhova-Thacker, E.V.; Boulahouache, C.; Bourdarios, C.; Bousson, N.; Boveia, A.; Boyd, J.; Boyko, I.R.; Bozhko, N.I.; Bozovic-Jelisavcic, I.; Bracinik, J.; Braem, A.; Brambilla, E.; Branchini, P.; Brandenburg, G.W.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J.E.; Braun, H.M.; Brelier, B.; Bremer, J.; Brenner, R.; Bressler, S.; Breton, D.; Brett, N.D.; Bright-Thomas, P.G.; Britton, D.; Brochu, F.M.; Brock, I.; Brock, R.; Brodbeck, T.J.; Brodet, E.; Broggi, F.; Bromberg, C.; Brooijmans, G.; Brooks, W.K.; Brown, G.; Brubaker, E.; Bruckman de Renstrom, P.A.; Bruncko, D.; Bruneliere, R.; Brunet, S.; Bruni, A.; Bruni, G.; Bruschi, M.; Buanes, T.; Bucci, F.; Buchanan, J.; Buchanan, N.J.; Buchholz, P.; Buckingham, R.M.; Buckley, A.G.; Buda, S.I.; Budagov, I.A.; Budick, B.; Buscher, V.; Bugge, L.; Buira-Clark, D.; Buis, E.J.; Bulekov, O.; Bunse, M.; Buran, T.; Burckhart, H.; Burdin, S.; Burgess, T.; Burke, S.; Busato, E.; Bussey, P.; Buszello, C.P.; Butin, F.; Butler, B.; Butler, J.M.; Buttar, C.M.; Butterworth, J.M.; Buttinger, W.; Byatt, T.; Cabrera Urban, S.; Caccia, M.; Caforio, D.; Cakir, O.; Calafiura, P.; Calderini, G.; Calfayan, P.; Calkins, R.; Caloba, L.P.; Caloi, R.; Calvet, D.; Calvet, S.; Camacho Toro, R.; Camard, A.; Camarri, P.; Cambiaghi, M.; Cameron, D.; Cammin, J.; Campana, S.; Campanelli, M.; Canale, V.; Canelli, F.; Canepa, A.; Cantero, J.; Capasso, L.; Capeans Garrido, M.D.M.; Caprini, I.; Caprini, M.; Capriotti, D.; Capua, M.; Caputo, R.; Caramarcu, C.; Cardarelli, R.; Carli, T.; Carlino, G.; Carminati, L.; Caron, B.; Caron, S.; Carpentieri, C.; Carrillo Montoya, G.D.; Carron Montero, S.; Carter, A.A.; Carter, J.R.; Carvalho, J.; Casadei, D.; Casado, M.P.; Cascella, M.; Caso, C.; Castaneda Hernandez, A.M.; Castaneda-Miranda, E.; Castillo Gimenez, V.; Castro, N.F.; Cataldi, G.; Cataneo, F.; Catinaccio, A.; Catmore, J.R.; Cattai, A.; Cattani, G.; Caughron, S.; Cavallari, A.; Cavalleri, P.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Cazzato, A.; Ceradini, F.; Cerna, C.; Cerqueira, A.S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cetin, S.A.; Cevenini, F.; Chafaq, A.; Chakraborty, D.; Chan, K.; Chapleau, B.; Chapman, J.D.; Chapman, J.W.; Chareyre, E.; Charlton, D.G.; Chavda, V.; Cheatham, S.; Chekanov, S.; Chekulaev, S.V.; Chelkov, G.A.; Chen, H.; Chen, L.; Chen, S.; Chen, T.; Chen, X.; Cheng, S.; Cheplakov, A.; Chepurnov, V.F.; Cherkaoui El Moursli, R.; Chernyatin, V.; Cheu, E.; Cheung, S.L.; Chevalier, L.; Chevallier, F.; Chiefari, G.; Chikovani, L.; Childers, J.T.; Chilingarov, A.; Chiodini, G.; Chizhov, M.V.; Choudalakis, G.; Chouridou, S.; Christidi, I.A.; Christov, A.; Chromek-Burckhart, D.; Chu, M.L.; Chudoba, J.; Ciapetti, G.; Ciftci, A.K.; Ciftci, R.; Cinca, D.; Cindro, V.; Ciobotaru, M.D.; Ciocca, C.; Ciocio, A.; Cirilli, M.; Ciubancan, M.; Clark, A.; Clark, P.J.; Cleland, W.; Clemens, J.C.; Clement, B.; Clement, C.; Clifft, R.W.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coe, P.; Cogan, J.G.; Coggeshall, J.; Cogneras, E.; Cojocaru, C.D.; Colas, J.; Colijn, A.P.; Collard, C.; Collins, N.J.; Collins-Tooth, C.; Collot, J.; Colon, G.; Coluccia, R.; Comune, G.; Conde Muino, P.; Coniavitis, E.; Conidi, M.C.; Consonni, M.; Constantinescu, S.; Conta, C.; Conventi, F.; Cook, J.; Cooke, M.; Cooper, B.D.; Cooper-Sarkar, A.M.; Cooper-Smith, N.J.; Copic, K.; Cornelissen, T.; Corradi, M.; Correard, S.; Corriveau, F.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M.J.; Costanzo, D.; Costin, T.; Cote, D.; Coura Torres, R.; Courneyea, L.; Cowan, G.; Cowden, C.; Cox, B.E.; Cranmer, K.; Cristinziani, M.; Crosetti, G.; Crupi, R.; Crepe-Renaudin, S.; Cuenca Almenar, C.; Cuhadar Donszelmann, T.; Cuneo, S.; Curatolo, M.; Curtis, C.J.; Cwetanski, P.; Czirr, H.; Czyczula, Z.; D'Auria, S.; D'Onofrio, M.; D'Orazio, A.; Da Rocha Gesualdi Mello, A.; Da Silva, P.V.M.; Da Via, C.; Dabrowski, W.; Dahlhoff, A.; Dai, T.; Dallapiccola, C.; Dallison, S.J.; Dam, M.; Dameri, M.; Damiani, D.S.; Danielsson, H.O.; Dankers, R.; Dannheim, D.; Dao, V.; Darbo, G.; Darlea, G.L.; Daum, C.; Dauvergne, J.P.; Davey, W.; Davidek, T.; Davidson, N.; Davidson, R.; Davies, M.; Davison, A.R.; Dawe, E.; Dawson, I.; Dawson, J.W.; Daya, R.K.; De, K.; de Asmundis, R.; De Castro, S.; De Cecco, S.; de Graat, J.; De Groot, N.; de Jong, P.; De La Cruz-Burelo, E.; De La Taille, C.; De Lotto, B.; De Mora, L.; De Nooij, L.; De Oliveira Branco, M.; De Pedis, D.; de Saintignon, P.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J.B.; Dean, S.; Dedes, G.; Dedovich, D.V.; Degenhardt, J.; Dehchar, M.; Deile, M.; Del Papa, C.; Del Peso, J.; Del Prete, T.; Dell'Acqua, A.; Dell'Asta, L.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delpierre, P.; Delruelle, N.; Delsart, P.A.; Deluca, C.; Demers, S.; Demichev, M.; Demirkoz, B.; Deng, J.; Denisov, S.P.; Dennis, C.; Derendarz, D.; Derkaoui, J.E.; Derue, F.; Dervan, P.; Desch, K.; Devetak, E.; Deviveiros, P.O.; Dewhurst, A.; DeWilde, B.; Dhaliwal, S.; Dhullipudi, R.; Di Ciaccio, A.; Di Ciaccio, L.; Di Girolamo, A.; Di Girolamo, B.; Di Luise, S.; Di Mattia, A.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Diaz, M.A.; Diblen, F.; Diehl, E.B.; Dietl, H.; Dietrich, J.; Dietzsch, T.A.; Diglio, S.; Dindar Yagci, K.; Dingfelder, J.; Dionisi, C.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djilkibaev, R.; Djobava, T.; do Vale, M.A.B.; Do Valle Wemans, A.; Doan, T.K.O.; Dobbs, M.; Dobinson, R.; Dobos, D.; Dobson, E.; Dobson, M.; Dodd, J.; Dogan, O.B.; Doglioni, C.; Doherty, T.; Doi, Y.; Dolejsi, J.; Dolenc, I.; Dolezal, Z.; Dolgoshein, B.A.; Dohmae, T.; Donadelli, M.; Donega, M.; Donini, J.; Dopke, J.; Doria, A.; Dos Anjos, A.; Dosil, M.; Dotti, A.; Dova, M.T.; Dowell, J.D.; Doxiadis, A.D.; Doyle, A.T.; Drasal, Z.; Drees, J.; Dressnandt, N.; Drevermann, H.; Driouichi, C.; Dris, M.; Drohan, J.G.; Dubbert, J.; Dubbs, T.; Dube, S.; Duchovni, E.; Duckeck, G.; Dudarev, A.; Dudziak, F.; Duhrssen, M.; Duerdoth, I.P.; Duflot, L.; Dufour, M-A.; Dunford, M.; Duran Yildiz, H.; Duxfield, R.; Dwuznik, M.; Dydak, F.; Dzahini, D.; Duren, M.; Ebke, J.; Eckert, S.; Eckweiler, S.; Edmonds, K.; Edwards, C.A.; Efthymiopoulos, I.; Ehrenfeld, W.; Ehrich, T.; Eifert, T.; Eigen, G.; Einsweiler, K.; Eisenhandler, E.; Ekelof, T.; El Kacimi, M.; Ellert, M.; Elles, S.; Ellinghaus, F.; Ellis, K.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Ely, R.; Emeliyanov, D.; Engelmann, R.; Engl, A.; Epp, B.; Eppig, A.; Erdmann, J.; Ereditato, A.; Eriksson, D.; Ernst, J.; Ernst, M.; Ernwein, J.; Errede, D.; Errede, S.; Ertel, E.; Escalier, M.; Escobar, C.; Espinal Curull, X.; Esposito, B.; Etienne, F.; Etienvre, A.I.; Etzion, E.; Evangelakou, D.; Evans, H.; Fabbri, L.; Fabre, C.; Facius, K.; Fakhrutdinov, R.M.; Falciano, S.; Falou, A.C.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farley, J.; Farooque, T.; Farrington, S.M.; Farthouat, P.; Fasching, D.; Fassnacht, P.; Fassouliotis, D.; Fatholahzadeh, B.; Favareto, A.; Fayard, L.; Fazio, S.; Febbraro, R.; Federic, P.; Fedin, O.L.; Fedorko, I.; Fedorko, W.; Fehling-Kaschek, M.; Feligioni, L.; Fellmann, D.; Felzmann, C.U.; Feng, C.; Feng, E.J.; 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Nurse, E.; Nyman, T.; O'Brien, B.J.; O'Neale, S.W.; O'Neil, D.C.; O'Shea, V.; Oakham, F.G.; Oberlack, H.; Ocariz, J.; Ochi, A.; Oda, S.; Odaka, S.; Odier, J.; Odino, G.A.; Ogren, H.; Oh, A.; Oh, S.H.; Ohm, C.C.; Ohshima, T.; Ohshita, H.; Ohska, T.K.; Ohsugi, T.; Okada, S.; Okawa, H.; Okumura, Y.; Okuyama, T.; Olcese, M.; Olchevski, A.G.; Oliveira, M.; Oliveira Damazio, D.; Oliver Garcia, E.; Olivito, D.; Olszewski, A.; Olszowska, J.; Omachi, C.; Onofre, A.; Onyisi, P.U.E.; Oram, C.J.; Ordonez, G.; Oreglia, M.J.; Orellana, F.; Oren, Y.; Orestano, D.; Orlov, I.; Oropeza Barrera, C.; Orr, R.S.; Ortega, E.O.; Osculati, B.; Ospanov, R.; Osuna, C.; Otero y Garzon, G.; Ottersbach, J.P; Ouchrif, M.; Ould-Saada, F.; Ouraou, A.; Ouyang, Q.; Owen, M.; Owen, S.; Oyarzun, A.; Oye, O.K.; Ozcan, V.E.; Ozturk, N.; Pacheco Pages, A.; Padilla Aranda, C.; Paganis, E.; Paige, F.; Pajchel, K.; Palestini, S.; Pallin, D.; Palma, A.; Palmer, J.D.; Pan, Y.B.; Panagiotopoulou, E.; Panes, B.; Panikashvili, N.; Panitkin, S.; Pantea, D.; Panuskova, M.; Paolone, V.; Paoloni, A.; Papadelis, A.; Papadopoulou, Th.D.; Paramonov, A.; Park, W.; Parker, M.A.; Parodi, F.; Parsons, J.A.; Parzefall, U.; Pasqualucci, E.; Passeri, A.; Pastore, F.; Pastore, Fr.; Pasztor, G.; Pataraia, S.; Patel, N.; Pater, J.R.; Patricelli, S.; Pauly, T.; Pecsy, M.; Pedraza Morales, M.I.; Peleganchuk, S.V.; Peng, H.; Pengo, R.; Penson, A.; Penwell, J.; Perantoni, M.; Perez, K.; Perez Cavalcanti, T.; Perez Codina, E.; Perez Garcia-Estan, M.T.; Perez Reale, V.; Peric, I.; Perini, L.; Pernegger, H.; Perrino, R.; Perrodo, P.; Persembe, S.; Perus, P.; Peshekhonov, V.D.; Peters, O.; Petersen, B.A.; Petersen, J.; Petersen, T.C.; Petit, E.; Petridis, A.; Petridou, C.; Petrolo, E.; Petrucci, F.; Petschull, D.; Petteni, M.; Pezoa, R.; Phan, A.; Phillips, A.W.; Phillips, P.W.; Piacquadio, G.; Piccaro, E.; Piccinini, M.; Pickford, A.; Piegaia, R.; Pilcher, J.E.; Pilkington, A.D.; Pina, J.; Pinamonti, M.; Pinder, A.; Pinfold, J.L.; Ping, J.; Pinto, B.; Pirotte, O.; Pizio, C.; Placakyte, R.; Plamondon, M.; Plano, W.G.; Pleier, M.A.; Pleskach, A.V.; Poblaguev, A.; Poddar, S.; Podlyski, F.; Poggioli, L.; Poghosyan, T.; Pohl, M.; Polci, F.; Polesello, G.; Policicchio, A.; Polini, A.; Poll, J.; Polychronakos, V.; Pomarede, D.M.; Pomeroy, D.; Pommes, K.; Pontecorvo, L.; Pope, B.G.; Popeneciu, G.A.; Popovic, D.S.; Poppleton, A.; Portell Bueso, X.; Porter, R.; Posch, C.; Pospelov, G.E.; Pospisil, S.; Potrap, I.N.; Potter, C.J.; Potter, C.T.; Poulard, G.; Poveda, J.; Prabhu, R.; Pralavorio, P.; Prasad, S.; Pravahan, R.; Prell, S.; Pretzl, K.; Pribyl, L.; Price, D.; Price, L.E.; Price, M.J.; Prichard, P.M.; Prieur, D.; Primavera, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Prudent, X.; Przysiezniak, H.; Psoroulas, S.; Ptacek, E.; Purdham, J.; Purohit, M.; Puzo, P.; Pylypchenko, Y.; Qian, J.; Qian, Z.; Qin, Z.; Quadt, A.; Quarrie, D.R.; Quayle, W.B.; Quinonez, F.; Raas, M.; Radescu, V.; Radics, B.; Rador, T.; Ragusa, F.; Rahal, G.; Rahimi, A.M.; Rajagopalan, S.; Rajek, S.; Rammensee, M.; Rammes, M.; Ramstedt, M.; Randrianarivony, K.; Ratoff, P.N.; Rauscher, F.; Rauter, E.; Raymond, M.; Read, A.L.; Rebuzzi, D.M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Reichold, A.; Reinherz-Aronis, E.; Reinsch, A.; Reisinger, I.; Reljic, D.; Rembser, C.; Ren, Z.L.; Renaud, A.; Renkel, P.; Rensch, B.; Rescigno, M.; Resconi, S.; Resende, B.; Reznicek, P.; Rezvani, R.; Richards, A.; Richter, R.; Richter-Was, E.; Ridel, M.; Rieke, S.; Rijpstra, M.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Rios, R.R.; Riu, I.; Rivoltella, G.; Rizatdinova, F.; Rizvi, E.; Robertson, S.H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J.E.M.; Robinson, M.; Robson, A.; Rocha de Lima, J.G.; Roda, C.; Roda Dos Santos, D.; Rodier, S.; Rodriguez, D.; Rodriguez Garcia, Y.; Roe, A.; Roe, S.; Rohne, O.; Rojo, V.; Rolli, S.; Romaniouk, A.; Romanov, V.M.; Romeo, G.; Romero Maltrana, D.; Roos, L.; Ros, E.; Rosati, S.; Rose, M.; Rosenbaum, G.A.; Rosenberg, E.I.; Rosendahl, P.L.; Rosselet, L.; Rossetti, V.; Rossi, E.; Rossi, L.P.; Rossi, L.; Rotaru, M.; Roth, I.; Rothberg, J.; Rottlander, I.; Rousseau, D.; Royon, C.R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubinskiy, I.; Ruckert, B.; Ruckstuhl, N.; Rud, V.I.; Rudolph, G.; Ruhr, F.; Ruiz-Martinez, A.; Rulikowska-Zarebska, E.; Rumiantsev, V.; Rumyantsev, L.; Runge, K.; Runolfsson, O.; Rurikova, Z.; Rusakovich, N.A.; Rust, D.R.; Rutherfoord, J.P.; Ruwiedel, C.; Ruzicka, P.; Ryabov, Y.F.; Ryadovikov, V.; Ryan, P.; Rybar, M.; Rybkin, G.; Ryder, N.C.; Rzaeva, S.; Saavedra, A.F.; Sadeh, I.; Sadrozinski, H.F-W.; Sadykov, R.; Safai Tehrani, F.; Sakamoto, H.; Salamanna, G.; Salamon, A.; Saleem, M.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvachua Ferrando, B.M.; Salvatore, D.; Salvatore, F.; Salzburger, A.; Sampsonidis, D.; Samset, B.H.; Sandaker, H.; Sander, H.G.; Sanders, M.P.; Sandhoff, M.; Sandhu, P.; Sandoval, T.; Sandstroem, R.; Sandvoss, S.; Sankey, D.P.C.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Santos, H.; Saraiva, J.G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sartisohn, G.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Sauvan, J.B.; Savard, P.; Savinov, V.; Savva, P.; Sawyer, L.; Saxon, D.H.; Says, L.P.; Sbarra, C.; Sbrizzi, A.; Scallon, O.; Scannicchio, D.A.; Schaarschmidt, J.; Schacht, P.; Schafer, U.; Schaetzel, S.; Schaffer, A.C.; Schaile, D.; Schamberger, R.D.; Schamov, A.G.; Scharf, V.; Schegelsky, V.A.; Scheirich, D.; Scherzer, M.I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schlereth, J.L.; Schmidt, E.; Schmidt, M.P.; Schmieden, K.; Schmitt, C.; Schmitz, M.; Schoning, A.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schroeder, C.; Schroer, N.; Schuh, S.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.C.; Schulz, H.; Schumacher, J.W.; Schumacher, M.; Schumm, B.A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W.G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S.C.; Seiden, A.; Seifert, F.; Seixas, J.M.; Sekhniaidze, G.; Seliverstov, D.M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M.E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L.Y.; Shank, J.T.; Shao, Q.T.; Shapiro, M.; Shatalov, P.B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M.J.; Short, D.; Shupe, M.A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siegert, F.; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S.B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N.B.; Sipica, V.; Siragusa, G.; Sisakyan, A.N.; Sivoklokov, S.Yu.; Sjolin, J.; Sjursen, T.B.; Skinnari, L.A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T.J.; Sloper, J.; Smakhtin, V.; Smirnov, S.Yu.; Smirnova, L.N.; Smirnova, O.; Smith, B.C.; Smith, D.; Smith, K.M.; Smizanska, M.; Smolek, K.; Snesarev, A.A.; Snow, S.W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C.A.; Solar, M.; Solc, J.; Soldevila, U.; Solfaroli Camillocci, E.; Solodkov, A.A.; Solovyanov, O.V.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spano, F.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R.D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stanecka, E.; Stanek, R.W.; Stanescu, C.; Stapnes, S.; Starchenko, E.A.; Stark, J.; Staroba, P.; Starovoitov, P.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H.J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G.A.; Stillings, J.A.; Stockmanns, T.; Stockton, M.C.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A.R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, E.; Strauss, M.; Strizenec, P.; Strohmer, R.; Strom, D.M.; Strong, J.A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Stupak, J.; Sturm, P.; Soh, D.A.; Su, D.; Subramania, S.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V.V.; Sultansoy, S.; Sumida, T.; Sun, X.; Sundermann, J.E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M.R.; Suzuki, Y.; Sviridov, Yu.M.; Swedish, S.; Sykora, I.; Sykora, T.; Szeless, B.; Sanchez, J.; Ta, D.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Taiblum, N.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M.C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tannoury, N.; Tappern, G.P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G.F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F.E.; Taylor, G.; Taylor, G.N.; Taylor, W.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K.K.; Ten Kate, H.; Teng, P.K.; Tennenbaum-Katan, Y.D.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R.J.; Tevlin, C.M.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J.P.; Thompson, E.N.; Thompson, P.D.; Thompson, P.D.; Thompson, A.S.; Thomson, E.; Thomson, M.; Thun, R.P.; Tic, T.; Tikhomirov, V.O.; Tikhonov, Y.A.; Timmermans, C.J.W.P.; Tipton, P.; Tique Aires Viegas, F.J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokar, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomoto, M.; Tompkins, L.; Toms, K.; Tonazzo, A.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N.D.; Torchiani, I.; Torrence, E.; Torro Pastor, E.; Toth, J.; Touchard, F.; Tovey, D.R.; Traynor, D.; Trefzger, T.; Treis, J.; Tremblet, L.; Tricoli, A.; Trigger, I.M.; Trincaz-Duvoid, S.; Trinh, T.N.; Tripiana, M.F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocme, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J.C-L.; Tsiakiris, M.; Tsiareshka, P.V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E.G.; Tsukerman, I.I.; Tsulaia, V.; Tsung, J.W.; Tsuno, S.; Tsybychev, D.; Tua, A.; Tuggle, J.M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Tuts, P.M.; Tykhonov, A.; Tylmad, M.; Tyndel, M.; Typaldos, D.; Tyrvainen, H.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D.G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urquijo, P.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J.A.; van der Graaf, H.; van der Kraaij, E.; van der Poel, E.; van der Ster, D.; Van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E.W.; Varouchas, D.; Vartapetian, A.; Varvell, K.E.; Vassilakopoulos, V.I.; Vazeille, F.; Vegni, G.; Veillet, J.J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Ventura, S.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J.C.; Vest, A.; Vetterli, M.C.; Vichou, I.; Vickey, T.; Viehhauser, G.H.A.; Viel, S.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M.G.; Vinek, E.; Vinogradov, V.B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A.P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T.T.; Vossebeld, J.H.; Vovenko, A.S.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Wakabayashi, J.; 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Wittgen, M.; Wolter, M.W.; Wolters, H.; Wooden, G.; Wosiek, B.K.; Wotschack, J.; Woudstra, M.J.; Wraight, K.; Wright, C.; Wrona, B.; Wu, S.L.; Wu, X.; Wu, Y.; Wulf, E.; Wunstorf, R.; Wynne, B.M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, U.K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, W-M.; Yao, Y.; Yasu, Y.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.; Yu, D.; Yu, J.; Yu, J.; Yuan, L.; Yurkewicz, A.; Zaets, V.G.; Zaidan, R.; Zaitsev, A.M.; Zajacova, Z.; Zalite, Yo.K.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zdrazil, M.; Zeitnitz, C.; Zeller, M.; Zema, P.F.; Zemla, A.; Zendler, C.; Zenin, A.V.; Zenin, O.; Zenis, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi della Porta, G.; Zhan, Z.; Zhang, D.; Zhang, H.; Zhang, J.; Zhang, X.; Zhang, Z.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C.G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zieminska, D.; Zilka, B.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Zivkovic, L.; Zmouchko, V.V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; zur Nedden, M.; Zutshi, V.; Zwalinski, L.

2013-07-16

Using the ATLAS detector, a centrality-dependent suppression has been observed in the yield of $J/{\\psi}$ mesons produced in the collisions of lead ions at the Large Hadron Collider. In a sample of minimum-bias lead-lead collisions at a nucleon-nucleon centre of mass energy $\\surd sNN$ = 2.76 TeV, corresponding to an integrated luminosity of about 6.7 ${\\mu}b^{-1}$, $J/{\\psi}$ mesons are reconstructed via their decays to ${\\mu}+{\\mu}-$ pairs. The measured $J/{\\psi}$ yield, normalized to the number of binary nucleon-nucleon collisions, is found to significantly decrease from peripheral to central collisions. The centrality dependence is found to be qualitatively similar to the trends observed at previous, lower energy experiments. The same sample is used to reconstruct Z bosons in the ${\\mu}+{\\mu}-$ final state, and a total of 38 candidates are selected in the mass window of 66 to 116 GeV. The relative Z yields as a function of centrality are also presented, although no conclusion can be inferred about their s...

A coupled-channels analysis of pion scattering and pion-induced eta production on the nucleon

International Nuclear Information System (INIS)

Pratt, R.K.; Bennhold, C.; Surya, Y.

1995-01-01

Motivated by new, upcoming Brookhaven data, pion scattering and pion-induced eta production on the nucleon in the S 11 (1535) resonance region is studied in an extension of the unitary, relativistic resonance model by Surya and Gross. The Kernel of the relativistic wave equation includes the nucleon, Roper, δ(1232), D 13 (1520) and S 11 (1535) pole terms along with contact σ- and ρ-like exchange terms. The formalism includes a coupling between the πN and ηN channels. The resonance parameters are adjusted to reproduce the experimental πN phase shifts

Relativistic generalizations of simple pion-nucleon models

International Nuclear Information System (INIS)

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

1981-01-01

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

The role of meson dynamics in nuclear matter saturation

International Nuclear Information System (INIS)

Goncalves, E.

1988-01-01

The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author) [pt

Dilepton and vector meson production in heavy-ion reactions

International Nuclear Information System (INIS)

Wolf, Gy.

1997-01-01

A nonperturbative dynamical study of dilepton an vector meson production in heavy-ion collisions from 1 to 2 GeV/A bombarding energies is presented incorporating all known sources relevant in this energy range. The dynamical evolution of the nucleus-nucleus collision is described by a transport equation of the Boltzmann-Uehling-Uhlenbeck type evolving phase-space distribution functions for nucleons, baryon resonances, pions, η's, ρ's and σ's with their isospin degrees of freedom. In particular, the sensitivity of the calculated yields to predicted changes of the ρ and ω mesons in dense matter is investigated. (author)

Meson exchange currents in nuclei; the triton beta decay as an example

International Nuclear Information System (INIS)

Jaus, W.

1976-01-01

The method used to reduce the four-dimensional Bethe-Salpeter equation to the three-dimensional Schroedinger equation, thus defining a potential in terms of the field theoretic interaction, can be generalized to define a consistent exchange by considering the relativistic interaction of a current with a bound state of nucleons. This covariant approach allows a unified treatment of exchange current effects, renormalization of the nuclear wave function due to meson exchange, relativistic corrections and negative energy contributions to the wave function and it is discussed in detail how these effects influence the Gamow-Teller matrix element for the decay 3 H→ 3 He + e + antiγ. One and two-meson exchange processes are calculated including nucleon resonances in intermediate states, and good agreement of theoretical and experimental predictions for the GT matrix element is found. (Auth.)

Exclusive vector meson production in muon-nucleus scattering

International Nuclear Information System (INIS)

Fang, G.Y.

1994-02-01

Preliminary results on the cross section ratios of exclusive incoherent ρ 0 and φ meson production off deuterium, carbon, calcium, and lead to that off hydrogen and coherent ρ 0 and φ meson production off calcium and lead to that off carbon in deep-inelastic muon-nucleon and muon-nucleus scattering are reported. The data were taken with the E665 spectrometer using the Fermilab Tevatron muon beam. The mean beam energy was 470 GeV. Increases in the cross section ratios are seen in both the elastic and quasi-elastic production as the four-momentum squared of the virtual photon increases. The results support the idea of color transparency

Electromagnetic properties of the three-nucleon ground state

International Nuclear Information System (INIS)

Strueve, W.

1985-01-01

The electromagnetic form factors of the three-nucleon ground state are calculated on the base of an exact solution of the Faddeev equations. In a Hilbert space of nucleons and a possible Δ-isobar the effects of a non-perturbative description of the Δ-isobar on the magnetic form factors are studied. Pure nucleonic current operators with two- and three-particle character can be described in the extended Hilbert space by simpler one-body operators. Additionally nonrelativistic meson-exchange corrections due to π and ρ exchange are calculated consistently with the requirements of current conservation. Further relativistic corrections are estimated on selected examples. The calculations yield a total magnetic contribution of the Δ-isobar which is smaller than hitherto assumed, a static approximation of the Δ propagation is proved as inadmissible and must be rejected. Together with the meson-exchange corrections a well agreement with the experimental data at low momentum transfers results. Especially the magnetic moments and magnetization radii can be explained. For higher momentum transfers the results show the importance of further corrections. The regard of selected relativistic corrections leads to a good description of the experimental magnetic form factors. Also by this way the position of the minimum and the height of the second maximum in the 3 He charge form factor can be explained. The comparison with the latest experimental results reveals furthermore unresolved problems in the description of the 3 H charge form factor. (orig.) [de

Covariant description of dynamical processes in relativistic nuclear matter

International Nuclear Information System (INIS)

Celenza, L.S.; Pantziris, A.; Shakin, C.M.

1992-01-01

We report results of covariant calculations of density-dependent polarization processes in relativistic nuclear matter. We consider the polarization induced by those mesons that play an important role in the boson-exchange model of nuclear forces (σ,π,ρ,ω). After obtaining the polarization operators, we construct the propagators for these mesons. The covariant nature of the calculation greatly clarifies the structure of the polarization operators and associated Green's functions. (In addition to the meson momentum, these quantities depend upon another four-vector, η μ , that describes the uniform motion of the medium.) In the case of the pion, we show that the same results are obtained for pseudovector or pseudoscalar coupling to the nucleon, if the associated Lagrangians are related by chiral transformations. Of particular interest are the extremely large values found for the polarization operators of the omega and sigma mesons. It is also found that the coupling of the sigma and omega fields through the polarization process is also extremely large. (Because of these results one cannot usefully consider the sigma and omega fields as independent degrees of freedom in nuclear matter.) We describe methods for reorganizing the calculation of ring diagrams in which we group those diagrams that exhibit strong cancellations. We also comment on the implication of our results for nuclear structure studies

Charmed meson rescattering in the reaction anti pd→ anti DDN

International Nuclear Information System (INIS)

Haidenbauer, J.; Krein, G.; Meissner, U.G.; Sibirtsev, A.

2008-01-01

We examine the possibility to extract information about the DN and anti DN interactions from the anti pd→D 0 D - p reaction. We utilize the notion that the open-charm mesons are first produced in the annihilation of the antiproton on one nucleon in the deuteron and subsequently rescatter on the other (the spectator) nucleon. The latter process is then exploited for investigating the DN and anti DN interactions. We study different methods for isolating the contributions from the D 0 p and D - p rescattering terms. (orig.)

Nucleonic gauging

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.)

Discerning the neutron density distribution of 208Pb from nucleon elastic scattering

International Nuclear Information System (INIS)

Karataglidis, S.; Amos, K.; University of Melbourne, VIC; Brown, B.A.; Deb, P.K.

2001-01-01

We seek a measure of the neutron density of 208 Pb from analyses of intermediate energy nucleon elastic scattering. The pertinent model for such analyses is based on coordinate space nonlocal optical potentials obtained from model nuclear ground state densities. As a calibration of the use of Skyrme-Hartree-Fock models the elastic scattering from 40 Cawas considered as well. Those potentials give predictions of integral observables and of angular distributions which show sensitivity to the neutron density. When compared with experiment, and correlated with analyses of electron scattering data, the results suggest that 208 Pb has a neutron skin thickness ∼ 0.17 fm

The role of the form factor and short-range correlation in the relativistic Hartree-Fock model for nuclear matter

Science.gov (United States)

Hu, J.; Toki, H.; Wen, W.; Shen, H.

2010-03-01

The role of the form factor and short-range correlation in nuclear matter is studied within the relativistic Hartree-Fock approximation. We take, first, the mean-field approximation for meson fields and obtain the fluctuation terms of mesons to be used for the Fock energies. We introduce form factors in the meson-nucleon coupling vertices to take into account the finite-size effect of the nucleon. We use further the unitary correlation operator method for the treatment of the short-range correlation. The form factors of the size ( Λ ˜ 1.0 -2.0GeV) of the nucleon-nucleon interaction cut down largely the contribution of the ρ -meson in the Fock term. The short-range correlation effect is not large but has a significant effect on the pion and ρ -meson energies in the relativistic Hartree-Fock approximation for nuclear matter.

D meson elliptic flow in non-central Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76TeV

CERN Document Server

Abelev, B.; Adamova, D.; Adare, A.M.; Aggarwal, M.M.; Aglieri Rinella, G.; Agnello, M.; Agocs, A.G.; Agostinelli, A.; Ahammed, Z.; Ahmad, N.; Masoodi, A.Ahmad; Ahmed, I.; Ahn, S.U.; Ahn, S.A.; Aimo, I.; Ajaz, M.; Akindinov, A.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altini, V.; Altinpinar, S.; Altsybeev, I.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Anson, C.; Anticic, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshauser, H.; Arbor, N.; Arcelli, S.; Arend, A.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I.C.; Arslandok, M.; Asryan, A.; Augustinus, A.; Averbeck, R.; Awes, T.C.; Aysto, J.; Azmi, M.D.; Bach, M.; Badala, A.; Baek, Y.W.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Ban, J.; Baral, R.C.; Barbera, R.; Barile, F.; Barnafoldi, G.G.; Barnby, L.S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batyunya, B.; Batzing, P.C.; Baumann, C.; Bearden, I.G.; Beck, H.; Behera, N.K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Bergognon, A.A.E.; Bertens, R.A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhati, A.K.; Bhom, J.; Bianchi, N.; Bianchi, L.; Bianchin, C.; Bielcik, J.; Bielcikova, J.; Bilandzic, A.; Bjelogrlic, S.; Blanco, F.; Blanco, F.; Blau, D.; Blume, C.; Boccioli, M.; Bottger, S.; Bogdanov, A.; Boggild, H.; Bogolyubsky, M.; Boldizsar, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossu, F.; Botje, M.; Botta, E.; Braidot, E.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T.A.; Browning, T.A.; Broz, M.; Brun, R.; Bruna, E.; Bruno, G.E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Canoa Roman, V.; Cara Romeo, G.; Carena, F.; Carena, W.; Carlin Filho, N.; Carminati, F.; Casanova Diaz, A.; Castillo Castellanos, J.; Castillo Hernandez, J.F.; Casula, E.A.R.; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J.L.; Chattopadhyay, S.; Chattopadhyay, S.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D.D.; Chochula, P.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C.H.; Christiansen, P.; Chujo, T.; Chung, S.U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Conesa Balbastre, G.; Conesa del Valle, Z.; Connors, M.E.; Contin, G.; Contreras, J.G.; Cormier, T.M.; Corrales Morales, Y.; Cortese, P.; Cortes Maldonado, I.; Cosentino, M.R.; Costa, F.; Cotallo, M.E.; Crescio, E.; Crochet, P.; Alaniz, E.Cruz; Albino, R.Cruz; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, S.; Das, K.; Das, I.; Das, D.; Dash, S.; Dash, A.; De, S.; de Barros, G.O.V.; De Caro, A.; De Cataldo, G.; de Cuveland, J.; De Falco, A.; De Gruttola, D.; Delagrange, H.; Deloff, A.; De Marco, N.; Denes, E.; De Pasquale, S.; Deppman, A.; Erasmo, G.D.; de Rooij, R.; Diaz Corchero, M.A.; Di Bari, D.; Dietel, T.; Di Giglio, C.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Divia, R.; Djuvsland, O.; Dobrin, A.; Dobrowolski, T.; Donigus, B.; Dordic, O.; Dubey, A.K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A.K.; Elia, D.; Elwood, B.G.; Emschermann, D.; Engel, H.; Erazmus, B.; Erdal, H.A.; Eschweiler, D.; Espagnon, B.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Eyyubova, G.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Fenton-Olsen, B.; Feofilov, G.; Fernandez Tellez, A.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M.A.S.; Filchagin, S.; Finogeev, D.; Fionda, F.M.; Fiore, E.M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Fusco Girard, M.; Gaardhoje, J.J.; Gagliardi, M.; Gago, A.; Gallio, M.; Gangadharan, D.R.; Ganoti, P.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Geuna, C.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glassel, P.; Goerlich, L.; Gomez, R.; Ferreiro, E.G.; Gonzalez-Zamora, P.; Gorbunov, S.; Goswami, A.; Gotovac, S.; Graczykowski, L.K.; Grajcarek, R.; Grelli, A.; Grigoras, C.; Grigoras, A.; Grigoriev, V.; Grigoryan, S.; Grigoryan, A.; Grinyov, B.; Grion, N.; Gros, P.; Grosse-Oetringhaus, J.F.; Grossiord, J.Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gunji, T.; Gupta, A.; Gupta, R.; Haake, R.; Haaland, O.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Han, B.H.; Hanratty, L.D.; Hansen, A.; Harris, J.W.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Hayrapetyan, A.; Heckel, S.T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Herrmann, N.; Hess, B.A.; Hetland, K.F.; Hicks, B.; Hippolyte, B.; Hori, Y.; Hristov, P.; Hrivnacova, I.; Huang, M.; Humanic, T.J.; Hwang, D.S.; Ichou, R.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Incani, E.; Innocenti, P.G.; Innocenti, G.M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivan, C.; Ivanov, A.; Ivanov, M.; Ivanov, V.; Ivanytskyi, O.; Jacholkowski, A.; Jacobs, P.M.; Jahnke, C.; Jang, H.J.; Janik, M.A.; Jayarathna, P.H.S.Y.; Jena, S.; Jha, D.M.; Jimenez Bustamante, R.T.; Jones, P.G.; Jung, H.; Jusko, A.; Kaidalov, A.B.; Kalcher, S.; Kalinak, P.; Kalliokoski, T.; Kalweit, A.; Kang, J.H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kazantsev, A.; Kebschull, U.; Keidel, R.; Ketzer, B.; Khan, S.A.; Khan, M.M.; Khan, K.H.; Khan, P.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, J.H.; Kim, D.W.; Kim, T.; Kim, S.; Kim, B.; Kim, M.; Kim, M.; Kim, J.S.; Kim, D.J.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Klay, J.L.; Klein, J.; Klein-Bosing, C.; Kliemant, M.; Kluge, A.; Knichel, M.L.; Knospe, A.G.; Kohler, M.K.; Kollegger, T.; Kolojvari, A.; Kompaniets, M.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Kralik, I.; Kramer, F.; Kravcakova, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Krus, M.; Kryshen, E.; Krzewicki, M.; Kucera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P.G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.B.; Kurepin, A.; Kuryakin, A.; Kushpil, S.; Kushpil, V.; Kvaerno, H.; Kweon, M.J.; Kwon, Y.; Ladron de Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; La Pointe, S.L.; Lara, C.; Lardeux, A.; La Rocca, P.; Lea, R.; Lechman, M.; Lee, S.C.; Lee, G.R.; Legrand, I.; Lehnert, J.; Lemmon, R.C.; Lenhardt, M.; Lenti, V.; Leon, H.; Leoncino, M.; Leon Monzon, I.; Levai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M.A.; Ljunggren, H.M.; Lodato, D.F.; Loenne, P.I.; Loggins, V.R.; Loginov, V.; Lohner, D.; Loizides, C.; Loo, K.K.; Lopez, X.; Lopez Torres, E.; Lovhoiden, G.; Lu, X.G.; Luettig, P.; Lunardon, M.; Luo, J.; Luparello, G.; Luzzi, C.; Ma, R.; Ma, K.; Madagodahettige-Don, D.M.; Maevskaya, A.; Mager, M.; Mahapatra, D.P.; Maire, A.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'Kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Mangotra, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mares, J.; Margagliotti, G.V.; Margotti, A.; Marin, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N.A.; Blanco, J.Martin; Martinengo, P.; Martinez, M.I.; Martinez Garcia, G.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazumder, R.; Mazzoni, M.A.; Meddi, F.; Menchaca-Rocha, A.; Mercado Perez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A.N.; Miskowiec, D.; Mitu, C.; Mizuno, S.; Mlynarz, J.; Mohanty, B.; Molnar, L.; Montano Zetina, L.; Monteno, M.; Montes, E.; Moon, T.; Morando, M.; Moreira De Godoy, D.A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Muhuri, S.; Mukherjee, M.; Muller, H.; Munhoz, M.G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B.K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, T.K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B.S.; Niida, T.; Nikolaev, S.; Nikolic, V.; Nikulin, S.; Nikulin, V.; Nilsen, B.S.; Nilsson, M.S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Nyanin, A.; Nyatha, A.; Nygaard, C.; Nystrand, J.; Ochirov, A.; Oeschler, H.; Oh, S.K.; Oh, S.; Oleniacz, J.; Oliveira Da Silva, A.C.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Ortona, G.; Oskarsson, A.; Ostrowski, P.; Otwinowski, J.; Oyama, K.; Ozawa, K.; Pachmayer, Y.; Pachr, M.; Padilla, F.; Pagano, P.; Paic, G.; Painke, F.; Pajares, C.; Pal, S.K.; Palaha, A.; Palmeri, A.; Papikyan, V.; Pappalardo, G.S.; Park, W.J.; Passfeld, A.; Patalakha, D.I.; Paticchio, V.; Paul, B.; Pavlinov, A.; Pawlak, T.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Perez Lara, C.E.; Perrino, D.; Peryt, W.; Pesci, A.; Pestov, Y.; Petracek, V.; Petran, M.; Petris, M.; Petrov, P.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Pitz, N.; Piyarathna, D.B.; Planinic, M.; Ploskon, M.; Pluta, J.; Pocheptsov, T.; Pochybova, S.; Podesta-Lerma, P.L.M.; Poghosyan, M.G.; Polak, K.; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Pospisil, V.; Potukuchi, B.; Prasad, S.K.; Preghenella, R.; Prino, F.; Pruneau, C.A.; Pshenichnov, I.; Puddu, G.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Rademakers, A.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, S.; Raniwala, R.; Rasanen, S.S.; Rascanu, B.T.; Rathee, D.; Rauch, W.; Rauf, A.W.; Razazi, V.; Read, K.F.; Real, J.S.; Redlich, K.; Reed, R.J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Renfordt, R.; Reolon, A.R.; Reshetin, A.; Rettig, F.; Revol, J.P.; Reygers, K.; Riccati, L.; Ricci, R.A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rodriguez Cahuantzi, M.; Rodriguez Manso, A.; Roed, K.; Rogochaya, E.; Rohr, D.; Rohrich, D.; Romita, R.; Ronchetti, F.; Rosnet, P.; Rossegger, S.; Rossi, A.; Roy, C.; Roy, P.; Rubio Montero, A.J.; Rui, R.; Russo, R.; Ryabinkin, E.; Rybicki, A.; Sadovsky, S.; Safarik, K.; Sahoo, R.; Sahu, P.K.; Saini, J.; Sakaguchi, H.; Sakai, S.; Sakata, D.; Salgado, C.A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sandor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Santoro, R.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R.P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H.R.; Schuchmann, S.; Schukraft, J.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Scott, P.A.; Segato, G.; Selyuzhenkov, I.; Senyukov, S.; Seo, J.; Serci, S.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Sharma, S.; Sharma, N.; Rohni, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Simonetti, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, T.; Sinha, B.C.; Sitar, B.; Sitta, M.; Skaali, T.B.; Skjerdal, K.; Smakal, R.; Smirnov, N.; Snellings, R.J.M.; Sogaard, C.; Soltz, R.; Song, M.; Song, J.; Soos, C.; Soramel, F.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B.K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J.H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A.A.P.; Subieta Vasquez, M.A.; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Sumbera, M.; Susa, T.; Symons, T.J.M.; Szanto de Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M.A.; J.Tapia Takaki, D.; Peloni, A.Tarantola; Tarazona Martinez, A.; Tauro, A.; Tejeda Munoz, G.; Telesca, A.; Minasyan, A.Ter; Terrevoli, C.; Thader, J.; Thomas, D.; Tieulent, R.; Timmins, A.R.; Tlusty, D.; Toia, A.; Torii, H.; Toscano, L.; Trubnikov, V.; Truesdale, D.; Trzaska, W.H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T.S.; Ulery, J.; Ullaland, K.; Ulrich, J.; Uras, A.; Urciuoli, G.M.; Usai, G.L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; Van Hoorne, J.W.; van Leeuwen, M.; Vannucci, L.; Vargas, A.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Venaruzzo, M.; Vercellin, E.; Vergara, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, Y.; Vinogradov, L.; Virgili, T.; Viyogi, Y.P.; Vodopyanov, A.; Volkl, M.A.; Voloshin, S.; Voloshin, K.; Volpe, G.; von Haller, B.; Vorobyev, I.; Vranic, D.; Vrlakova, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, V.; Wang, Y.; Wang, M.; Wang, Y.; Watanabe, K.; Weber, M.; Wessels, J.P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Williams, M.C.S.; Windelband, B.; Winn, M.; Yaldo, C.G.; Yamaguchi, Y.; Yang, S.; Yang, H.; Yang, P.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I.K.; Yoon, J.; Yuan, X.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Zavada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zelnicek, P.; Zgura, I.S.; Zhalov, M.; Zhang, Y.; Zhang, H.; Zhang, X.; Zhou, D.; Zhou, Y.; Zhou, F.; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zinovjev, G.; Zoccarato, Y.; Zynovyev, M.; Zyzak, M.

2013-01-01

Azimuthally anisotropic distributions of $D^0, D^+$ and $D^{*+}$ mesons were studied in the central rapidity region (|y| < 0.8) in Pb-Pb collisions at a centre-of-mass energy $\\sqrt{s_{NN}}$ = 2.76 TeV per nucleon-nucleon collision, with the ALICE detector at the LHC. The second Fourier coefficient $\

DS Mesons in Asymmetric Hot and Dense Hadronic Matter

Directory of Open Access Journals (Sweden)

Divakar Pathak

2015-01-01

Full Text Available The in-medium properties of DS mesons are investigated within the framework of an effective hadronic model, which is a generalization of a chiral SU(3 model, to SU(4, in order to study the interactions of the charmed hadrons. In the present work, the DS mesons are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the DS+ and DS- mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the medium. Additionally, in hyperonic medium, the mass degeneracy of the DS mesons is observed to be broken, due to opposite signs of the Weinberg-Tomozawa interaction term in the Lagrangian density. Along with the magnitude of the mass drops, the mass splitting between DS+ and DS- mesons is also observed to grow with an increase in baryonic density and strangeness content of the medium. However, all medium effects analyzed are found to be weakly dependent on isospin asymmetry and temperature. We discuss the possible implications emanating from this analysis, which are all expected to make a significant difference to observables in heavy ion collision experiments, especially the upcoming Compressed Baryonic Matter (CBM experiment at the future Facility for Antiproton and Ion Research (FAIR, GSI, where matter at high baryonic densities is planned to be produced.

Quark and diquark fragmentation into mesons and baryons

International Nuclear Information System (INIS)

Bartl, A.; Fraas, H.; Majerotto, W.

1981-01-01

Quark and diquark fragmentation into mesons and baryons is treated in a cascade-type model based on six coupled integral equations. An analytic solution including flavour dependence is found. Comparison with experimental data is given. Our results indicate a probability of about 50 percent for the diquark to break up. (Author)

Vector meson decays in the chiral bag model

International Nuclear Information System (INIS)

Maxwell, O.V.; Jennings, B.K.

1985-01-01

Vector meson decays are examined in a model where a confined quark and antiquark annihilate, producing a pair of elementary pseudoscalar mesons. Two versions of the pseudoscalar meson-quark interaction are employed, one where the coupling is restricted to the bag surface and one where it extends throughout the bag volume. Energy conservation is ensured in the model through insertion of exponential factors containing the bag energy at each interaction vertex. To guarantee momentum conservation, a wave-packet description is utilized in which the decay widths are normalized by a factor involving the overlap of the initial bag state with the confined qanti q state of zero momentum. With either interaction, the model yields a value for the p-width that exceeds the empirical width by a factor two. For the Ksup(*) and PHI mesons, the computed widths depend strongly on the interaction employed. Implications of these results for chiral bag models are discussed. (orig.)

A unitarized meson model including color Coulomb interaction

International Nuclear Information System (INIS)

Metzger, Kees.

1990-01-01

Ch. 1 gives a general introduction into the problem field of the thesis. It discusses in how far the internal structure of mesons is understood theoretically and which models exist. It discusses from a phenomenological point of view the problem of confinement indicates how quark models of mesons may provide insight in this phenomenon. In ch. 2 the formal theory of scattering in a system with confinement is given. It is shown how a coupled channel (CC) description and the work of other authors fit into this general framework. Explicit examples and arguments are given to support the CC treatment of such a system. In ch. 3 the full coupled-channel model as is employed in this thesis is presented. On the basis of arguments from the former chapters and the observed regularities in the experimental data, the choices underlying the model are supported. In this model confinement is described with a mass-dependent harmonic-oscillator potential and the presence of open (meson-meson) channels plays an essential role. In ch. 4 the unitarized model is applied to light scalar meson resonances. In this regime the contribution of the open channels is considerable. It is demonstrated that the model parameters as used for the description of the pseudo-scalar and vector mesons, unchanged can be used for the description of these mesons. Ch. 5 treats the color-Coulomb interaction. There the effect of the Coulomb interaction is studied in simple models without decay. The results of incorporating the color-Coulomb interaction into the full CC model are given in ch.6. Ch. 7 discusses the results of the previous chapters and the present status of the model. (author). 182 refs.; 16 figs.; 33 tabs

Measurement of prompt D-meson production in p-Pb collisions at $\\sqrt{s_{NN}}$ = 5.02 TeV

CERN Document Server

Abelev, Betty Bezverkhny; Adamova, Dagmar; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agostinelli, Andrea; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Nazeer; Ahmed, Ijaz; Ahn, Sang Un; Ahn, Sul-Ah; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; 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Shangaraev, Artem; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarazona Martinez, Alfonso; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wagner, Vladimir; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yang, Shiming; Yano, Satoshi; Yasnopolskiy, Stanislav; Yi, Jungyu; Yin, Zhongbao; Yoo, In-Kwon; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zaman, Ali; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zyzak, Maksym

2014-12-04

The $p_T$-differential production cross sections of the prompt charmed mesons $D^0, D^+, D^{*+}$ and $D_s^+$ and their charge conjugate in the rapidity interval -0.96 < $y_{cms}$ < 0.04 were measured in p-Pb collisions at a centre-of-mass energy $\\sqrt{s_{NN}}$ = 5.02 TeV with the ALICE detector at the LHC. The nuclear modification factor $R_{pPb}$, quantifying the D-meson yield in p--Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15-20% uncertainties with unity in the transverse momentum interval 1 < $p_T$ < 24 GeV/c. No significant difference among the $R_{pPb}$ of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects i...

Measurement of prompt D-meson production in p-Pb collisions at √(s(NN))=5.02 TeV.

Science.gov (United States)

Abelev, B; Adam, J; Adamová, D; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agostinelli, A; Agrawal, N; Ahammed, Z; Ahmad, N; Ahmed, I; Ahn, S U; Ahn, S A; Aimo, I; Aiola, S; Ajaz, M; Akindinov, A; Alam, S N; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arcelli, S; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Augustinus, A; Averbeck, R; Awes, T C; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batyunya, B; Batzing, P C; Baumann, C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Belmont, R; 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Grigoryan, S; Grinyov, B; Grion, N; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gumbo, M; Gunji, T; Gupta, A; Gupta, R; Khan, K H; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hanratty, L D; Hansen, A; Harris, J W; Hartmann, H; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Hess, B A; Hetland, K F; Hippolyte, B; Hladky, J; Hristov, P; Huang, M; Humanic, T J; Hussain, N; Hutter, D; Hwang, D S; Ilkaev, R; Ilkiv, I; Inaba, M; Innocenti, G M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, M; Ivanov, V; Jachołkowski, A; Jacobs, P M; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, C; Jena, S; Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kadyshevskiy, V; Kalcher, S; Kalinak, P; Kalweit, A; Kamin, J; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kebschull, U; Keidel, R; Keijdener, D L D; Khan, M M; Khan, P; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, B; Kim, D W; Kim, D J; Kim, J S; Kim, M; Kim, M; Kim, S; Kim, T; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, J; Klein-Bösing, C; Kluge, A; Knichel, M L; Knospe, A G; Kobdaj, C; Kofarago, M; Köhler, M K; Kollegger, T; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Kryshen, E; Krzewicki, M; Kučera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kweon, M J; Kwon, Y; Ladron de Guevara, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; Lara, C; Lardeux, A; Lattuca, A; La Pointe, S L; La Rocca, P; Lea, R; Leardini, L; Lee, G R; Legrand, I; Lehnert, J; Lemmon, R C; Lenti, V; Leogrande, E; Leoncino, M; León Monzón, I; Lévai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Lodato, D F; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Lopez, X; López Torres, E; Lu, X-G; Luettig, P; Lunardon, M; Luparello, G; Luzzi, C; Ma, R; Maevskaya, A; Mager, M; Mahapatra, D P; Mahmood, S M; Maire, A; Majka, R D; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Manko, V; Manso, F; Manzari, V; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Marín, A; Markert, C; Marquard, M; Martashvili, I; Martin, N A; Martinengo, P; Martínez, M I; Martínez García, G; Martin Blanco, J; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matyja, A; Mayer, C; Mazer, J; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Meninno, E; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitra, J; Mitu, C M; Mlynarz, J; Mohammadi, N; 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Röhrich, D; Romita, R; Ronchetti, F; Ronflette, L; Rosnet, P; Rossi, A; Roukoutakis, F; Roy, A; Roy, C; Roy, P; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Ryabov, Y; Rybicki, A; Sadovsky, S; Šafařík, K; Sahlmuller, B; Sahoo, R; Sahu, P K; Saini, J; Sakai, S; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sánchez Rodríguez, F J; Šándor, L; Sandoval, A; Sano, M; Santagati, G; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Segato, G; Seger, J E; Sekiguchi, Y; Selyuzhenkov, I; Seo, J; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Shangaraev, A; Sharma, N; Sharma, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; 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Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Velure, A; Venaruzzo, M; Vercellin, E; Vergara Limón, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S A; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, J; Wagner, V; Wang, M; Wang, Y; Watanabe, D; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Windelband, B; Winn, M; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, P; Yang, S; Yano, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I-K; Yushmanov, I; Zaccolo, V; Zach, C; Zaman, A; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zgura, I S; Zhalov, M; Zhang, H; Zhang, X; Zhang, Y; Zhao, C; Zhigareva, N; Zhou, D; Zhou, F; Zhou, Y; Zhou, Z; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zimmermann, M B; Zinovjev, G; Zoccarato, Y; Zyzak, M

2014-12-05

The p_{T}-differential production cross sections of the prompt charmed mesons D^{0}, D^{+}, D^{*+}, and D_{s}^{+} and their charge conjugate in the rapidity interval -0.96meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%-20% uncertainties with unity in the transverse momentum interval 1meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.

Q.C.D. predictions for the forward photoproduction of heavy vector mesons

International Nuclear Information System (INIS)

Navelet, H.; Peschanski, R.

1984-03-01

From the inelastic QantiQ-Nucleon cross section, we get predictions for the forward photoproduction of heavy QantiQ mesons by using V.D.M. and the optical theorem. These cross sections are computed from perturbative Q.C.D. through gluon radiation mechanism

Vibronic coupling density and related concepts

International Nuclear Information System (INIS)

Sato, Tohru; Uejima, Motoyuki; Iwahara, Naoya; Haruta, Naoki; Shizu, Katsuyuki; Tanaka, Kazuyoshi

2013-01-01

Vibronic coupling density is derived from a general point of view as a one-electron property density. Related concepts as well as their applications are presented. Linear and nonlinear vibronic coupling density and related concepts, orbital vibronic coupling density, reduced vibronic coupling density, atomic vibronic coupling constant, and effective vibronic coupling density, illustrate the origin of vibronic couplings and enable us to design novel functional molecules or to elucidate chemical reactions. Transition dipole moment density is defined as an example of the one-electron property density. Vibronic coupling density and transition dipole moment density open a way to design light-emitting molecules with high efficiency.

Old tensor mesons in QCD sum rules

International Nuclear Information System (INIS)

Aliev, T.M.; Shifman, M.A.

1981-01-01

Tensor mesons f, A 2 and A 3 are analyzed within the framework of QCD sum rules. The effects of gluon and quark condensate is accounted for phenomenologically. Accurate estimates of meson masses and coupling constants of the lowest-lying states are obtained. It is shown that the masses are reproduced within theoretical uncertainty of about 80 MeV. The coupling of f meson to the corresponding quark current is determined. The results are in good aqreement with experimental data [ru

Application of RQMD and FRITIOF models for description of nucleus-nucleus interactions at energy of 3.36 GeV/nucleon

International Nuclear Information System (INIS)

Galoyan, A.S.; Kladnitskaya, E.N.; Rogachevskij, O.V.; Uzhinskij, V.V.

2001-01-01

Experimental data on proton and π - -meson rapidity distributions in CC-interactions at 3.36 GeV/nucleon in the events with different multiplicities of produced π - -mesons are presented. The data are compared with predictions of RQMD and FRITIOF models. It is shown that the RQMD model reproduces satisfactorily the π - -meson distributions, but unsatisfactorily describes the protons characteristics. The FRITIOF model gives good results at tuning the free parameters of the model

ϕ-Meson production at forward rapidity in p–Pb collisions at sNN=5.02 TeV and in pp collisions at s=2.76 TeV

Directory of Open Access Journals (Sweden)

J. Adam

2017-05-01

Full Text Available The first study of ϕ-meson production in p–Pb collisions at forward and backward rapidity, at a nucleon–nucleon centre-of-mass energy sNN=5.02 TeV, has been performed with the ALICE apparatus at the LHC. The ϕ-mesons have been identified in the dimuon decay channel in the transverse momentum (pT range 1nucleon centre-of-mass — the integrated luminosity amounting to 5.01±0.19 nb−1 and 5.81±0.20 nb−1, respectively, for the two data samples. Differential cross sections as a function of transverse momentum and rapidity are presented. The forward–backward ratio for ϕ-meson production is measured for 2.96<|y|<3.53, resulting in a ratio ∼0.5 with no significant pT dependence within the uncertainties. The pT dependence of the ϕ nuclear modification factor RpPb exhibits an enhancement up to a factor 1.6 at pT=3–4 GeV/c in the Pb-going direction. The pT dependence of the ϕ-meson cross section in pp collisions at s=2.76 TeV, which is used to determine a reference for the p–Pb results, is also presented here for 1

Weak interactions in deuterons: exchange currents and nucleon-nucleon interactions

International Nuclear Information System (INIS)

Dautry, F.; Rho, M.; Riska, D.O.

1976-01-01

While the meson-exchange electromagnetic current has been tested with an impressive success in the two-nucleon system, nothing much is known about the reliability of the exchange currents in weak interactions. This question is studied using muon absorption in the deuteron, μ - + d→n + n + γ. The meson-exchange current, previously derived in parallel to those of the electromagnetic interaction, is checked for consistency against the p-wave piece of the p + p→d + π + process near threshold and then tested with the total capture rate for which some (though not so accurate) data are available. The same Hamiltonian is then used to calculate the matrix elements for the solar neutrino processes p + p→d + e + + γ and p + p + e - → d + γ in the hope that they would be measured and help resolve the solar neutrino puzzle. Finally a detailed analysis is made of the differential capture rate dGAMMA/dEsub(n), Esub(n) being the kinematic energy in the c.m. of the two neutrons, in the expectation that it will be used to pin down the ever elusive n-n scattering length. (Auth.)

A theory of scalar mesons

International Nuclear Information System (INIS)

Hooft, G. t'; Isidori, G.; Maiani, L.; Polosa, A.D.; Riquer, V.

2008-01-01

We discuss the effect of the instanton induced, six-fermion effective Lagrangian on the decays of the lightest scalar mesons in the diquark-antidiquark picture. This addition allows for a remarkably good description of light scalar meson decays. The same effective Lagrangian produces a mixing of the lightest scalars with the positive parity qq-bar states. Comparing with previous work where the qq-bar mesons are identified with the nonet at 1200-1700 MeV, we find that the mixing required to fit the mass spectrum is in good agreement with the instanton coupling obtained from light scalar decays. A coherent picture of scalar mesons as a mixture of tetraquark states (dominating in the lightest mesons) and heavy qq-bar states (dominating in the heavier mesons) emerges

Associative birth of the J/PSI meson and photon in the polarizing ep and pp interactions

International Nuclear Information System (INIS)

Temiraliev, A.T.

2001-01-01

Appearance of so named 'spin crisis' acutely states the problem about role of gluons and sea quacks in nucleon spin structure function. For revealing of gluons contribution the joint birth of J/PSI meson and photon with opposite transverse impulse in polarizing electron-proton and proton-proton interactions have been studied. Calculation have been carried within the framework of the theory of quantum chromodynamics collisions. Charming meson decay into either electron-positron pair or meson pair gives experimental pure finite state. Measurement of the polarizing asymmetry of associative birth of J/PSI meson and photon in the result of both experiments (ep and pp) allow to determine gluons polarization unambiguously

Medium effects on spin observables of proton knockout reactions

International Nuclear Information System (INIS)

Krein, G.; Maris, T.A.J.; Rodrigues, B.B.; Veit, E.A.

1994-07-01

Medium modifications of the properties of bound nucleons and mesons are investigated by means of medium energy quasi free proton knockout reactions with polarized incident protons. The sensitivity of the spin observables of these reactions to modifications of the nucleon and meson properties is studied using the Bonn one-boson exchange model of the nucleon-nucleon interaction. A method proposed to extract the pp analysing power in medium from the (p, 2 p) asymmetries indicates a reduction of this quantity compared to its free space value. This reduction is linked to modifications of masses and coupling constants of the nucleons and mesons in the nucleus. The implications of these modifications for another spin observable to be measured in the future are discussed. (author). 39 refs, 9 figs

Medium effects on spin observables of proton knockout reactions

Energy Technology Data Exchange (ETDEWEB)

Krein, G [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Maris, T A.J.; Rodrigues, B B; Veit, E A [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica

1994-07-01

Medium modifications of the properties of bound nucleons and mesons are investigated by means of medium energy quasi free proton knockout reactions with polarized incident protons. The sensitivity of the spin observables of these reactions to modifications of the nucleon and meson properties is studied using the Bonn one-boson exchange model of the nucleon-nucleon interaction. A method proposed to extract the pp analysing power in medium from the (p, 2 p) asymmetries indicates a reduction of this quantity compared to its free space value. This reduction is linked to modifications of masses and coupling constants of the nucleons and mesons in the nucleus. The implications of these modifications for another spin observable to be measured in the future are discussed. (author). 39 refs, 9 figs.

Measurement of D-meson production versus multiplicity in p-Pb collisions at $\\sqrt{s_{\\rm NN}}=5.02$ TeV

CERN Document Server

Adam, J.; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahn, Sang Un; Aiola, Salvatore; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Millan Almaraz, Jesus Roberto; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Arnaldi, Roberta; Arnold, Oliver Werner; Arsene, Ionut Cristian; Arslandok, Mesut; Audurier, Benjamin; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Balasubramanian, Supraja; Baldisseri, Alberto; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; 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Telesca, Adriana; Terasaki, Kohei; Terrevoli, Cristina; Teyssier, Boris; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trogolo, Stefano; Trombetta, Giuseppe; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Utrobicic, Antonija; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Vanat, Tomas; Vande Vyvre, Pierre; Varga, Dezso; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vauthier, Astrid; Vechernin, Vladimir; Veen, Annelies Marianne; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Villatoro Tello, Abraham; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Vislavicius, Vytautas; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Wagner, Boris; Wagner, Jan; Wang, Hongkai; Wang, Mengliang; Watanabe, Daisuke; Watanabe, Yosuke; Weber, Michael; Weber, Steffen Georg; Weiser, Dennis Franz; Wessels, Johannes Peter; Westerhoff, Uwe; Whitehead, Andile Mothegi; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yasar, Cigdem; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yoon, Jin Hee; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zardoshti, Nima; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Chunhui, Zhang; Zhang, Zuman; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

2016-08-11

The measurement of prompt D-meson production as a function of multiplicity in p–Pb collisions at $\\sqrt{s_{\\rm NN}}=5.02$ TeV with the ALICE detector at the LHC is reported. D$^0$, D$^+$ and D$^{*+}$ mesons are reconstructed via their hadronic decay channels in the centre-of-mass rapidity range $-0.96 < y_{\\rm cms} < 0.04$ and transverse momentum interval $1 < p_{\\rm T}<24$ GeV/c. The multiplicity dependence of D-meson production is examined by either comparing yields in p–Pb collisions in different event classes, selected based on the multiplicity of produced particles or zero-degree energy, with those in pp collisions, scaled by the number of binary nucleon–nucleon collisions (nuclear modification factor); as well as by evaluating the per-event yields in p–Pb collisions in different multiplicity intervals normalized to the multiplicity-integrated ones (relative yields). The nuclear modification factors for D$^0$, D$^+$ and D$^{*+}$ are consistent with one another. The D-meson nuclear mod...

QCD vacuum tensor susceptibility and properties of transversely polarized mesons

International Nuclear Information System (INIS)

Bakulev, A.P.; Mikhajlov, S.V.

1999-01-01

We re-estimate the tensor susceptibility of QCD vacuum, χ, and to this end, we re-estimate the leptonic decay constants for transversely polarized ρ-, ρ'- and b 1 -mesons. The origin of the susceptibility is analyzed using duality between ρ- and b 1 -channels in a 2-point correlator of tensor currents and disagree with [2] on both OPE expansion and the value of QCD vacuum tensor susceptibility. Using our value for the latter we determine new estimations of nucleon tensor charges related to the first moment of the transverse structure functions h 1 of a nucleon

Axial coupling constant of the nucleon for two flavours of dynamical quarks in finite and infinite volume

International Nuclear Information System (INIS)

Khan, A.A.; Goeckeler, M.; Haegler, P.

2006-03-01

We present data for the axial coupling constant g A of the nucleon obtained in lattice QCD with two degenerate flavours of dynamical non-perturbatively improved Wilson quarks. The renormalisation is also performed non-perturbatively. For the analysis we give a chiral extrapolation formula for g A based on the small scale expansion scheme of chiral effective field theory for two degenerate quark flavours. Applying this formalism in a finite volume we derive a formula that allows us to extrapolate our data simultaneously to the infinite volume and to the chiral limit. Using the additional lattice data in finite volume we are able to determine the axial coupling of the nucleon in the chiral limit without imposing the known value at the physical point. (Orig.)

Axial coupling constant of the nucleon for two flavours of dynamical quarks in finite and infinite volume

Energy Technology Data Exchange (ETDEWEB)

Khan, A.A.; Goeckeler, M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Haegler, P. [Technische Univ. Muenchen (DE). Physik-Department, Theoretische Physik] (and others)

2006-03-15

We present data for the axial coupling constant g{sub A} of the nucleon obtained in lattice QCD with two degenerate flavours of dynamical non-perturbatively improved Wilson quarks. The renormalisation is also performed non-perturbatively. For the analysis we give a chiral extrapolation formula for g{sub A} based on the small scale expansion scheme of chiral effective field theory for two degenerate quark flavours. Applying this formalism in a finite volume we derive a formula that allows us to extrapolate our data simultaneously to the infinite volume and to the chiral limit. Using the additional lattice data in finite volume we are able to determine the axial coupling of the nucleon in the chiral limit without imposing the known value at the physical point. (Orig.)

The role of the form factor and short-range correlation in the relativistic Hartree-Fock model for nuclear matter

International Nuclear Information System (INIS)

Hu, J.; Toki, H.; Wen, W.; Shen, H.

2010-01-01

The role of the form factor and short-range correlation in nuclear matter is studied within the relativistic Hartree-Fock approximation. We take, first, the mean-field approximation for meson fields and obtain the fluctuation terms of mesons to be used for the Fock energies. We introduce form factors in the meson-nucleon coupling vertices to take into account the finite-size effect of the nucleon. We use further the unitary correlation operator method for the treatment of the short-range correlation. The form factors of the size (Λ∝1.0 -2.0 GeV) of the nucleon-nucleon interaction cut down largely the contribution of the ρ-meson in the Fock term. The short-range correlation effect is not large but has a significant effect on the pion and ρ-meson energies in the relativistic Hartree-Fock approximation for nuclear matter. (orig.)

The nuclear spin-orbit coupling

International Nuclear Information System (INIS)

Bell, J.S.; Skyrme, T.H.R.

1994-01-01

Analysis of the nucleon-nucleon scattering around 100 MeV has determined the spin-orbit coupling part of the two-body scattering matrix at that energy, and a reasonable extrapolation to lower energies is possible. This scattering amplitude has been used, in the spirit of Brueckner's nuclear model, to estimate the resultant single-body spin-orbit coupling for a single nucleon interacting with a large nucleus. This resultant potential has a radial dependence approximately proportional to r -1 d ρ /dr, and with a magnitude in good agreement with that required to explain the doublet splittings in nuclei and the polarization of nucleons scattered elastically off nuclei. (author). 14 refs, 2 figs

Mean free paths and in-medium scattering cross sections of energetic nucleons in neutron-rich nucleonic matter within the relativistic impulse approximation

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

A transverse lattice QCD model for mesons

Energy Technology Data Exchange (ETDEWEB)

Patel, Apoorva D.; Ratabole, Raghunath

2004-03-01

QCD is analysed with two light-front continuum dimensions and two transverse lattice dimensions. In the limit of large number of colours and strong transverse gauge coupling, the contributions of light-front and transverse directions factorise in the dynamics, and the theory can be analytically solved in a closed form. An integral equation is obtained, describing the properties of mesons, which generalises the 't Hooft equation by including spin degrees of freedom. The meson spectrum, light-front wavefunctions and form factors can be obtained by solving this equation numerically. These results would be a good starting point to model QCD observables which only weakly depend on transverse directions, e.g. deep inelastic scattering structure functions.

Calculation of the total potential between two deformed heavy ion nuclei using the Monte Carlo method and M3Y nucleon-nucleon forces

International Nuclear Information System (INIS)

Ghodsi, O. N.; Zanganeh, V.

2009-01-01

In the current study, a simulation technique has been employed to calculate the total potential between two deformed nuclei. It has been shown that this simulation technique is an efficient one for calculating the total potential for all possible orientations between the symmetry axes of the interacting nuclei using the realistic nuclear matter density and the M3Y nucleon-nucleon effective forces. The analysis of the results obtained for the 48 Ca+ 238 U, 46 Ti+ 46 Ti, and 27 Al+ 70 Ge reactions reveal that considering the density dependent effects in the M3Y forces causes the nuclear potential to drop by an amount of 0.4 MeV.

Probing non nucleonic degrees of freedom with strong and electromagnetic interactions

International Nuclear Information System (INIS)

Frois, B.

1985-10-01

In this talk, I would like to examine our present view on non-nucleonic degrees of freedom with a few typical experimental results obtained recently both with hadronic and electromagnetic probes at intermediate energies. It is the first generation of experimental data which has probed mesonic degrees of freedom with a spatial resolution of the order of 0.5 fm. This has made possible for example the measurement of the size of the pion-nucleon interaction region. This is very stimulating progress and we begin to have a coherent overview on the various reaction mechanisms which are induced by hadronic and electromagnetic probes

Some open issues in nucleon-antinucleon interaction

International Nuclear Information System (INIS)

Richard, J.M.

1990-01-01

The conventional picture of the NN-bar (nucleon-antinucleon) interaction at low energy relies on the superposition of a long-range elastic potential and a short-range absorption. The meson-exchange model, which has been successful until the opening of LEAR, is not likely to survive the LEAR-ACOL era. Recent data on spin observables contradict the predictions of potential models. Annihilation and long-range forces are discussed as well as quasi-bound baryonium states. (K.A.) 11 refs

Production of charm mesons by high energy neutrons

International Nuclear Information System (INIS)

Shipbaugh, C.L.

1988-01-01

The charmed mesons D/sup /plus minus//, D/sup 0/, and D/sub s//sup /plus minus//, have been observed in neutron-nucleus collisions at the FNAL Tevatron. A sample of 134 /plus minus/ 19 events as investigated in the decay D/sup /plus minus// /yields/ D/sup 0//pi//sup /plus minus// with the subsequent decay mode D/sup 0/ /yields/ K/sup +/K/sup /minus//. The cross section per nucleon for D/sup /plus minus//, at most probable energy /radical/s = 35 GeV, was measured to be 2.11 /plus minus/ .43 (plus minus/.63)/mu/b/nucleon for 0.0 < x/sub f/ < 0.14 (/bar x//sub f/ = .07). The branching ratio (BR) is defined as: BR /identical to/ Br(D /yields/ D/pi/) /times/ BR(D /yields/ K/sup +/K/sup /minus//). The dependence of the cross section per nucleus on number of nucleons in target was fit to a form A /sup /alpha// and it was found that /alpha/ = .96 /plus minus/ .17. A sample of 64 /plus minus/ 16 D/sub s//sup /plus minus// events was investigates for the decay D/sub s//sup /plus minus// /yields/ /phi//pi//sup /plus minus//. The differential cross section for D/sub s//sup /plus minus// production averaged over the particle and antiparticle states is: BR.[1/2](d/sigma/(D/sub s//sup +/)/dx/sub f/ + d/sigma/(D/sub s//sup /minus//) = 2.85 /plus minus/ 0.80 /plus minus/ .86 /mu/b/nucleon at x/sub f/ = 0.175 where the first errors is statistical and the second error is systematic. The branching fraction is defined as BR /equivalent to/ BR(D/sub s/ /yields/ /phi//pi/), and a linear A dependence was assumed. An estimate of relative cross section is: 0.19 /plus minus/ 0.09 at x/sub f/ = 0. 36 refs., 43 figs., 5 tabs

Influence of the nuclear level density on the odd-even staggering in 56Fe+p spallation at energies from 300 to 1500 MeV/nucleon

Science.gov (United States)

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

On the nucleon renormalization in many nucleon problems due to pionic degrees of freedom

International Nuclear Information System (INIS)

Sauer, P.U.; Sawicki, M.; Furui, Sadataka.

1985-01-01

Conceptual problems of unified two-nucleon force models are discussed. The force models are based on the pion-nucleon vertex and attempt a description of the nucleon-nucleon interaction below and above pion threshold. The conceptual problems arise from the nucleon renormalization due to pionic degrees of freedom. Keeping channels with a single pion only no renormalization procedure can be given which is consistent in the one-nucleon and in the many-nucleon systems. The medium dependence of the one-pion exchange potential is illustrated. (author)

Interplay of mesonic and baryonic degrees of freedom in quark matter

Energy Technology Data Exchange (ETDEWEB)

Khan, Naseemuddin

2015-11-03

In this work we study the influence of mesonic and baryonic fluctuations on the phase diagram of quark matter with two flavors. By examining the hadronization process and related techniques, we derive effective low-energy models, where the gluons are integrated out. To be able to compare our model calculations with lattice results at finite chemical potential, we investigate a QCD-like theory with two colors, where the sign-problem is absent. To this end we introduce a quark-meson-diquark model, where the bosonic diquarks play the role of colorless, baryonic degrees of freedom competing with the mesons. To access the phase diagram and determine the phases of chiral and diquark condensation, we employ a functional renormalization group approach allowing for a systematic non-perturbative truncation scheme. Interesting phenomena arise that are known from condensed matter physics, as the BEC-BSC crossover and a phase of condensation within domains. We explore the impact of running wave function renormalizations and Yukawa couplings for the quarks and the boson fields on top of the scale dependence of the effective potential. In the course of this we discuss the Silver Blaze property and its realization within a functional approach. In parallel, we formulate a quark-meson-diquark-baryon model for physical QCD as a low-energy effective theory for baryonic matter at high density, and discuss the relevance of the diquark and baryon degrees of freedom. In this sense, we compute a phase diagram for QCD from functional methods, including a color superconducting phase.

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

Nuclear matter calculations with a pseudoscalar-pseudovector chiral model

Energy Technology Data Exchange (ETDEWEB)

Niembro, R.; Marcos, S.; Bernardos, P. [University of Cantabria, Faculty of Sciences, Department of Modern Physics, 39005 Santander (Spain); Fomenko, V.N. [St Petersburg University for Railway Engineering, Department of Mathematics, 197341 St Petersburg (Russian Federation); Savushkin, L.N. [St Petersburg University for Telecomunications, Department of Physics, 191065 St Petersburg (Russian Federation); Lopez-Quelle, M. [University of Cantabria, Faculty of Sciences, Department of Applied Physics, 39005 Santander, Spain (Spain)

1998-10-01

A mixed pseudoscalar-pseudovector {pi}N coupling relativistic Lagrangian is obtained from a pure pseudoscalar chiral one, by transforming the nucleon field according to a generalized Weinberg transformation, which depends on a mixing parameter. The interaction is generated by the {sigma}, {omega} and {pi} meson exchanges. Within the Hartree-Fock context, pion polarization effects, including the {delta} isobar, are considered in the random phase approximation in nuclear matter. These effects are interpreted, in a non-relativistic framework, as a modification of the range and intensity of a Yukawa-type potential by means of a simple function which takes into account the nucleon-hole and {delta}-hole excitations. Results show stability of relativistic nuclear matter against pion condensation. Compression modulus is diminished by the combined effects of the nucleon and {delta} polarization towards the usually accepted experimental values. The {pi}N interaction strength used in this paper is less than the conventional one to ensure the viability of the model. The fitting parameters of the model are the scalar meson mass m{sub {sigma}} and the {omega}-N coupling constant g{sub {omega}}. (author)

One-dimensional time-dependent fluid model of a very high density low-pressure inductively coupled plasma

Science.gov (United States)

Chaplin, Vernon H.; Bellan, Paul M.

2015-12-01

A time-dependent two-fluid model has been developed to understand axial variations in the plasma parameters in a very high density (peak ne≳ 5 ×1019 m-3 ) argon inductively coupled discharge in a long 1.1 cm radius tube. The model equations are written in 1D with radial losses to the tube walls accounted for by the inclusion of effective particle and energy sink terms. The ambipolar diffusion equation and electron energy equation are solved to find the electron density ne(z ,t ) and temperature Te(z ,t ) , and the populations of the neutral argon 4s metastable, 4s resonant, and 4p excited state manifolds are calculated to determine the stepwise ionization rate and calculate radiative energy losses. The model has been validated through comparisons with Langmuir probe ion saturation current measurements; close agreement between the simulated and measured axial plasma density profiles and the initial density rise rate at each location was obtained at pA r=30 -60 mTorr . We present detailed results from calculations at 60 mTorr, including the time-dependent electron temperature, excited state populations, and energy budget within and downstream of the radiofrequency antenna.

Use of a finite range nucleon-nucleon interaction in the continuum shell model

International Nuclear Information System (INIS)

Faes, Jean-Baptiste

2007-01-01

The unification of nuclear structure and nuclear reactions was always a great challenge of nuclear physics. The extreme complexity of finite quantum systems lead in the past to a separate development of the nuclear structure and the nuclear reactions. A unified description of structure and reactions is possible within the continuum shell model. All previous applications of this model used the zero-range residual interaction and the finite depth local potential to generate the single-particle basis. In the thesis, we have presented an extension of the continuum shell model for finite-range nucleon-nucleon interaction and an arbitrary number of nucleons in the scattering continuum. The great advantage of the present formulation is the same two-body interaction used both to generate the single-particle basis and to describe couplings to the continuum states. This formulation opens a possibility for an ab initio continuum shell model studies with the same nucleon-nucleon interaction generating the nuclear mean field, the configuration mixing and the coupling to the scattering continuum. First realistic applications of the above model has been shown for spectra of "1"7F and "1"7O, and elastic phase-shifts in the reaction "1"6O(p, p)"1"6O. (author)

The nucleon-nucleon spin-orbit interaction in the Skyrme model

International Nuclear Information System (INIS)

Riska, D.O.; Dannbom, K.

1987-01-01

The spin-orbit and quadratic spin-orbit components of the nucleon-nucleon interaction are derived in the Skyrme model at the classical level. These interaction components arise from the orbital and rotational motion of the soliton fields that form the nucleons. The isospin dependent part of the spin-orbit interaction is similar to the corresponding component obtained from boson exchange mechanisms at long distances although at short distances it is weaker. The isospin independent spin-orbit component is however different from the prediction of boson exchange mechanisms and has the opposite sign. The quadratic spin-orbit interaction is weak and has only an isospin dependent component

Yields of clustered DNA damage induced by charged-particle radiations of similar kinetic energy per nucleon: LET dependence in different DNA microenvironments

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.

The QCD model of hadron cores of the meson theory

International Nuclear Information System (INIS)

Pokrovskii, Y.E.

1985-01-01

It was shown that in the previously proposed QCD model of hadron cores the exchange and self-energy contributions of the virtual quark-antiquark-gluon cloud on the outside of a bag which radius coincides with the hardon core radius of the meson theory (∼ 0.4 Fm) have been taken into account at the phenomenological level. Simulation of this cloud by the meson field results in realistic estimations of the nucleon's electroweak properties, moment fractions carried by gluons, quarks, antiquarks and hadron-hadron interaction cross-sections within a wide range of energies. The authors note that the QCD hadron core model proposed earlier not only realistically reflects the hadron masses, but reflects self-consistently main elements of the structure and interaction of hadrons at the quark-gluon bag radius (R - 0.4Fm) being close to the meson theory core radius

Shear viscosity of neutron-rich nucleonic matter near its liquid–gas phase transition

International Nuclear Information System (INIS)

Xu, Jun; Chen, Lie-Wen; Ko, Che Ming; Li, Bao-An; Ma, Yu Gang

2013-01-01

Within a relaxation time approach using free nucleon–nucleon cross sections modified by the in-medium nucleon masses that are determined from an isospin- and momentum-dependent effective nucleon–nucleon interaction, we investigate the specific shear viscosity (η/s) of neutron-rich nucleonic matter near its liquid–gas phase transition. It is found that as the nucleonic matter is heated at fixed pressure or compressed at fixed temperature, its specific shear viscosity shows a valley shape in the temperature or density dependence, with the minimum located at the boundary of the phase transition. Moreover, the value of η/s drops suddenly at the first-order liquid–gas phase transition temperature, reaching as low as 4–5 times the KSS bound of ℏ/4π. However, it varies smoothly for the second-order liquid–gas phase transition. Effects of the isospin degree of freedom and the nuclear symmetry energy on the value of η/s are also discussed

On the meson exchange currents contribution in deep inelastic scattering on deuteron

International Nuclear Information System (INIS)

Kaptar', L.P.; Titov, A.I.; Umnikov, A.Yu.

1988-01-01

The contribution of the one- and two-pion exchange currents to the deep inelastic deuteron structure function F 2 D (x) is considered. It is shown that the mesonic corrections do not restore the energy sum rule violated by the off-mass-shell properties of the bound nucleons

Weak NNM couplings and nuclear parity violation

International Nuclear Information System (INIS)

Holstein, B.R.

1987-01-01

After many years of careful theoretical and experimental study of nuclear parity violation, rough empirical values for weak parity violation nucleon-nucleon-meson vertices have been deduced. We address some of the physics which has been learned from this effort and show that it has implications for work going on outside this field. (author)

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

International Nuclear Information System (INIS)

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

1996-01-01

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