The generalized two-center cluster model, which can treat static structures and dynamical reactions in excited states, is applied to the light neutron-rich system, ¹²Be=α+α+4N. We discuss the change of the neutrons’ configuration around two α cores from the covalent structure to the ionic one. ...

We propose a search for the newly discovered tetraquark candidate Z(4430) in photoproduction. Based on the Belle results, we show that if Z(4430) is a genuine resonance, its significantly large coupling to ψ^′π will cause it to stand out above the background in γp→Z⁺(4430)n→ψ^′π⁺n. We con...

Next-to-leading-order (NLO) QCD corrections to double J/ψ production in e⁺e^- annihilation at sqrt[s] =10.6  GeV are calculated. We find that they greatly decrease the cross section, with a K factor (NLO/LO) ranging from -0.31 to 0.25 depending on the renormalization scale. Although the renormal...

The anomalous excess of low-energy ν_e events measured in the MiniBooNE experiment is explained through a renormalization of the absolute neutrino flux and a simultaneous disappearance of the ν_e’s in the beam, which is compatible with that indicated by the results of gallium radioactive source ex...

The extended radius of a halo nuclide is very sensitive to the minute binding energy of its valence nucleons. The binding energy of ¹¹Li has been measured with high precision by using the radio-frequency spectrometer MISTRAL at CERN’s ISOLDE facility. The new two-neutron separation energy of 378±...

It is well known that the instanton approach to QCD generates an effective term which looks like a three-flavor determinant of quark bilinears. This has the right behavior to explain the unusual mass and mixing of the η(958) meson, as is often simply illustrated with the aid of a linear SU(3) sigma...

We present a comprehensive study of the lowest moments of nucleon generalized parton distributions in N_f=2+1 lattice QCD using domain-wall valence quarks and improved staggered sea quarks. Our investigation includes helicity dependent and independent generalized parton distributions for pion masses ...

The dimensionless parameter ξ=M_π²/(16π²F_π²), where F_π is the pion decay constant and M_π is the pion mass, is expected to control the convergence of chiral perturbation theory applicable to QCD. Here we demonstrate that a strongly coupled lattice gauge theory model with the same symmetries as t...

We derive a second-order linear differential equation for the leading-order gluon distribution function G(x,Q²)=xg(x,Q²) which determines G(x,Q²) directly from the proton structure function F₂^p(x,Q²). This equation is derived from the leading-order evolution equation for F₂^p(x,Q²), and does not requ...

We measure the hyperfine splitting of the 9S_1/2 level of ²¹⁰Fr, and find a magnetic dipole hyperfine constant A=622.25(36)  MHz. The theoretical value, obtained using the relativistic all-order method from the electronic wave function at the nucleus, allows us to extract a nuclear magnetic momen...

We study the physics at finite nuclear density in the framework of the AdS/QCD model with a holographic baryon field included. Based on a mean field type approach, we introduce the nucleon density as a bi-fermion condensate of the lowest mode of the baryon field and calculate the density dependence ...

The relation of the shear viscosity coefficient to the recently introduced transport rate is derived within relativistic kinetic theory. We calculate the shear viscosity over entropy ratio η/s for a gluon gas, which involves elastic gg→gg perturbative QCD (PQCD) scatterings as well as inelastic g...

We derive correlated bounds on ratios of deep inelastic structure functions from the dipole picture of photon-hadron scattering at high energies. In particular we consider ratios of the longitudinal structure function, the total structure function, and the charm part of the latter. We also consider ...

We present results for the nucleon axial charge g_A at a fixed lattice spacing of 1/a=1.73(3)  GeV using 2+1 flavors of domain wall fermions on size 16³Ã—32 and 24³Ã—64 lattices (L=1.8 and 2.7 fm) with length 16 in the fifth dimension. The length of the Monte Carlo trajectory at the lightest m_Ï...

Inclusive inelastic electron scattering off the deuteron under 180° has been studied at the S-DALINAC close to the breakup threshold at momentum transfers q=0.27  fm^-1 and 0.74  fm^-1 with good energy resolution sufficient to map in detail the spin flip M1 response, which governs the startin...

We present a specific class of models for an infrared-finite analytic QCD coupling, such that at large spacelike energy scales the coupling differs from the perturbative one by less than any inverse power of the energy scale. This condition is motivated by the Institute for Theoretical and Experimen...

We study hadronization of the final state in a particle-antiparticle annihilation using a holographic gravity dual description of QCD. At the point of hadronization we match the events to a simple (Gaussian) energy distribution in the five dimensional theory. The final state multiplicities are then ...

A detailed analysis of the effect of short-range and tensor correlations on one- and two-nucleon momentum distributions of medium-weight nuclei (12≤A≤40) is carried out. Although our Letter is primarily aimed at understanding the role of the tensor force on nucleon momentum distributions of medi...

We study how the charge neutrality affects the phase structure of the three-flavor Polyakov-loop Nambu–Jona-Lasinio (PNJL) model. We point out that, within the conventional PNJL model at finite density, the color neutrality is missing because the Wilson line serves as an external colored field cou...

We investigate the structure of protoneutron stars (PNS) formed by hadronic and quark matter in β-equilibrium described by appropriate equations of state (EOS). For the hadronic matter, we use a finite temperature EOS based on the Brueckner-Bethe-Goldstone many-body theory, with realistic two- and ...

Photoneutron cross sections were measured for ⁹¹Zr, ⁹²Zr, and ⁹⁴Zr near the neutron separation energy with quasimonochromatic γ rays. The data exhibit some extra components around the neutron threshold. A coherent analysis of the photoneutron data for ⁹²Zr together with the neutron capture on ⁹¹Zr...

We perform a lattice Monte Carlo calculation of the trace-anomaly two-point function at finite temperature in the SU(3) gauge theory. We obtain the long distance properties of the correlator in the continuum limit and extract the bulk viscosity ζ via a Kubo formula. Unlike the tensor correlator re...

The beam-spin asymmetries in the hard exclusive electroproduction of photons on the proton (e→p→epγ) were measured over a wide kinematic range and with high statistical accuracy. These asymmetries result from the interference of the Bethe-Heitler process and of deeply virtual Compton scattering...

An ensemble with random n-body interactions is investigated in the presence of symmetries. A striking emergence of regularities in the spectra, ground state spins, and isospins is discovered. In even-particle systems the strong preponderance of spin zero ground states is observed with three, four, a...

A novel internal target has been developed, which will make electron scattering off short-lived radioactive nuclei possible in an electron storage ring. An “ion trapping” phenomenon in the electron storage ring was successfully utilized for the first time to form the target for electron scatteri...

In-beam γ-ray spectroscopy of ^66,68Fe following intermediate-energy one- and two-proton knockout from cobalt and nickel secondary beams has been performed at the National Superconducting Cyclotron Laboratory. New transitions have been observed in ⁶⁶Fe and ⁶⁸Fe. This is the first observation of γ-r...

The connections between the E(5) models [the original E(5) using an infinite square well, E(5)-β⁴, E(5)-β⁶, and E(5)-β⁸], based on particular solutions of the geometrical Bohr Hamiltonian with γ-unstable potentials, and the interacting boson model (IBM) are explored. For that purpose, the genera...

The fusion-evaporation reaction ⁹Be(¹¹B,2p) was used to populate excited states in ¹⁸N. New gamma-ray transitions were added to the ¹⁸N level scheme. The mean lifetime of the first excited state was measured to be 582(165) ps and its transition rate to the ground state was determined to be B(M1)=0.0...

Two-quasiparticle states in ²⁵⁰Bk were investigated with decay scheme studies and the single-neutron transfer reaction ²⁴⁹Bk(d,p)²⁵⁰Bk. Mass-separated sources of ²⁵⁴Es were used for α singles and α-γ coincidence measurements. These studies, plus previous studies of ²⁵⁴Es^m α decay and the ²⁴⁹Bk(n...

Excited states of the extremely neutron-deficient radon isotopes with N=111,113,115 have been studied for the first time in a series of in-beam experiments performed at the Accelerator Laboratory of the University of Jyväskylä. The reactions used were: ¹¹⁸Sn(⁸²Kr, 3n)¹⁹⁷Rn, ¹²⁰Sn(⁸²Kr, 3n)¹⁹⁹Rn, ^1...

Excited low-spin, nonyrast states in ^170,172,174Hf were populated in β⁺/ε decay and studied through off-beam γ-ray spectroscopy. New coincidence data allowed for a substantial revision of the level schemes of ^170,172Hf and a confirmation of the level scheme of ¹⁷⁴Hf. The Hf isotopes represent a u...

We propose a new method to solve the Hartree-Fock-Bogoliubov equations for weakly bound nuclei, which works for both spherical and axially deformed cases. In this approach, the quasiparticle wave functions are expanded in a complete set of analytical Pöschl-Teller-Ginocchio and Bessel/Coulomb wave ...

The highly selective reactions ¹²C(⁷Li,d)¹⁷O and ¹²C(⁶Li,p)¹⁷O have been used to populate high-lying excited states in ¹⁷O up to 16 MeV in excitation. Several of the states are newly observed, and the existence of others in a previous study of ¹²C(⁶Li,p)¹⁷O is confirmed. The observed spectra show a ...

We discuss the Garvey-Kelson mass relations in an extended formalism and show how they can be used to test and improve the consistency of the most commonly used mass formulas to achieve more accurate predictions.

New levels have been established above the 861-keV, 9/2⁺ isomeric state in ⁶¹Fe. The observations can be reproduced satisfactorily by shell model calculations, but only after a significant lowering of the νg_9/2 single-particle energy with respect to the value determined empirically from levels outs...

An isomeric state in ²⁰⁹Ra has been observed for the first time, using the GABRIELA setup at the focal plane of VASSILISSA, to decay to the ground state of ²⁰⁹Ra via a cascade of 238-keV (M2) and 644-keV transitions. The half-life of the isomer has been measured to be 117(5) μs and from systemati...

A fission formalism which describes transmission and absorption through multiple humped barriers using a recursive method is proposed. Developed within the optical model for fission, it accounts for the fission mechanisms associated to the different degrees of damping of the vibrational states accom...

The neutron capture cross sections of the radioactive isotope ¹⁸²Hf (t_1/2=8.9×10⁶ yr) in the thermal and epithermal energy regions have been measured by activation at the TRIGA Mark-II reactor of the Atomic Institute of the Austrian Universities in Vienna, Austria, and subsequent γ-ray spectroscop...

A microscopic potential is derived in correlation with the necking region within the fission-like shape on the basis of potential theory. The whole microscopic potential is of the two-center type, yielding the evolution of proton and neutron level schemes from one parent to two completely separated ...

We simulate the dynamics of Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC) with a hybrid model that treats the dense early quark-gluon plasma (QGP) stage macroscopically as an ideal fluid but models the dilute late hadron resonance gas (HG) microscopically using a hadronic cascade. B...

A Bethe-Salpeter-Faddeev (BSF) calculation is performed for the pentaquark Θ⁺ in the diquark picture of Jaffe and Wilczek in which Θ⁺ is a diquark-diquark-s̅ three-body system. The Nambu–Jona-Lasinio (NJL) model is used to calculate the lowest order diagrams in the two-body scatterings...

The bound kaon approach to the strangeness in the Skyrme model is applied to investigating the possibility of deeply bound K^-pp states. We describe the K^-pp system as two Skyrmion, around which a kaon field fluctuates. Each Skyrmion is rotated in the space of SU(2) collective coordinate. The rotatio...

We compute the inclusive cross section of f₂ tensor-meson production in proton-proton collisions at high energy. We use an effective theory inspired from the tensor-meson dominance hypothesis that couples gluons to f₂ mesons. We compute the differential cross section in the k_⊥ factorization and in...

Recently, we suggested that low-energy β-beam neutrinos can be very useful for the study of supernova-neutrino interactions. In this article, we examine the use of a such experiment for the analysis of a supernova-neutrino signal. Because supernova neutrinos are oscillating, it is very likely that ...

The reaction ²⁴Mg(α,γ)²⁸Si is involved in the nucleosynthesis of ²⁴Mg and ²⁸Si in massive stars. The reaction has not been examined with sufficient sensitivity at α-particle energies below 1.5 MeV. Several ²⁸Si states appear favorable for formation by this reaction in the α-particle energy range...

Fusion reactions in the crust of an accreting neutron star are an important source of heat, and the depth at which these reactions occur is important for determining the temperature profile of the star. Fusion reactions depend strongly on the nuclear charge Z. Nuclei with Z⩽6 can fuse at low densi...

Unstable modes in asymmetric nuclear matter (ANM) at subsaturation densities are studied in the framework of relativistic mean-field density-dependent hadron models. The size of the instabilities that drive the system are calculated and a comparison with results obtained within the nonlinear Walecka...

The mixing between sterile and active neutrinos is taken into account in the calculation of Big Bang Nucleosynthesis. The abundances of primordial elements, like D, ³He, ⁴He, and ⁷Li, are calculated by including sterile neutrinos and by using finite chemical potentials. It is found that the resultin...

The functional renormalization group is applied to the effective action for scattering of two nonrelativistic fermions. The resulting physical effective action is shown to contain the correct threshold singularity. The corresponding “bare” action respects Galilean invariance up to second order i...

The complex scaled hyperspherical adiabatic expansion method is used to compute momentum and energy distributions of the three a-particles emerging from the decay of low-lying 12C-resonances. The large distance continuum properties of the wave functions are crucial and must be accurately calculated. We discuss separately decays of natural parity states: two 0+, one 1-, three 2+, one 3-, two 4+, one 6+, and one of each of unnatural parity, 1+, 2-, 3+, 4-. The lowest natural parity state of each Jp decays predominantly sequentially via the 8Be ground state whereas other states including unnatural parity states predominantly decay directly to the continuum. We present Dalitz plots and systematic detailed momentum correlations of the emerging a-particles.

We show that single-particle energies in doubly magic nuclei depend almost linearly on the coupling constants of the nuclear energy density functional. Therefore, they can be very well characterized by the linear regression coefficients, which we calculate for the coupling constants of the standard Skyrme functional. We then use these regression coefficients to refit the coupling constants to experimental values of single-particle energies. We show that the obtained rms deviations from experimental data are still quite large, of the order of 1.1 MeV. This suggests that the current standard form of the Skyrme functional cannot ensure spectroscopic-quality description of single-particle energies, and that extensions of this form are very much required.

We study the spatial structure of four valence neutrons in the ground state of 8He and 18C nuclei using a core+4n model. For this purpose, we employ a density-dependent contact interaction among the valence neutrons, and solve the five-body Hamiltonian in the Hartree-Fock-Bogoliubov (HFB) approximation. We show that two neutrons with the coupled spin of S=0 exhibit a strong dineutron correlation around the surface of these nuclei, whereas the correlation between the two dineutrons is much weaker. Our calculation indicates that the probability of the (1p3/2)4 and [(1p3/2)2 (p1/2)2] configurations in the ground state wave function of 8He nucleus is 34.9% and 23.7%, respectively. This is consistent with the recent experimental finding with the 8He(p,t)6He reaction, that is, the ground state wave function of 8He deviates significantly from the pure (1p3/2)4 structure.

The a particle preformation in the even-even nuclei from 108Te to 294118 and the penetration probability have been studied. The isotopes from Pb to U have been firstly investigated since the experimental data allow to extract the microscopic features for each element. The assault frequency has been estimated using classical methods and the penetration probability from tunneling through the Generalized Liquid Drop Model (GLDM) potential barrier. The preformation factor has been extracted from experimental a decay energies and half-lives. The shell closure effects play the key role in the a preformation. The more the nucleon number is close to the magic numbers, the more the formation of a cluster is difficult inside the mother nucleus. The penetration probabilities reflect that 126 is a neutron magic number. The penetration probability range is very large compared to that of the preformation factor. The penetration probability determines mainly the a decay half-life while the preformation factor allows to obtain information on the nuclear structure. The study has been extended to the newly observed heaviest nuclei.

We examine the magnetic moments and beta-decay lifetimes of light T=1/2 mirror nuclei and obtain very tight correlations between these quantities by making use of shell-model estimates for small quantities. Using the information thus obtained, we predict values for some unknown magnetic moments of heavier T=1/2 mirror nuclei. Correlations for the magnetic moments of some T=3/2 mirror nuclei are also included. The effective operators required to reproduce the data are discussed and compared to those obtained with other methods.

A study of first and second order nuclear shape phase transitional behavior in yrast states of even-even nuclei in the context of the Interacting Boson Model-1 is presented. Finite boson number effects are identified using calculations with up to 150 bosons, and the role of the rotational degree of freedom of observables in first and second order quantum phase transitional nuclei is discussed. We aim to provide a first investigation of the angular momentum dependence of experimentally-accessible phase transitional signatures in finite-sized quantum nuclear systems.

Using a shell model which is capable of describing the spectra of upper g9/2-shell nuclei close to the N=Z line, we study the structure of two isomeric states 7+ and 21+ in the odd-odd N=Z nucleus 94Ag. It is found that both isomeric states exhibit a large collectivity. The 7+ state is oblately deformed, and is suggested to be a shape isomer in nature. The 21+ state becomes isomeric because of level inversion of the 19+ and 21+ states due to core excitations across the N=Z=50 shell gap. Calculation of spectroscopic quadrupole moment indicates clearly an enhancement in these states due to the core excitations. However, the present shell model calculation that produces the 19+-21+ level inversion cannot accept the large-deformation picture of Mukha et al. in Nature 439, 298 (2006).

We describe a procedure for mapping a self-consistent mean-field theory (also known as density functional theory) onto a shell model Hamiltonian that includes quadrupole-quadrupole and monopole pairing interactions in a truncated space. We test our method in the deformed N=Z sd-shell nuclei 20Ne, 24Mg and 36Ar, starting from the Hartree-Fock plus BCS approximation of the USD shell model interaction. A similar method is then followed using the SLy4 Skyrme energy density functional in the particle-hole channel plus a zero-range density-dependent force in the pairing channel. Based on the ground-state solution of this density functional theory at the Hartree-Fock plus BCS level, an effective shell model Hamiltonian is constructed. We apply this mapped Hamiltonian to extract quadrupolar and pairing correlation energies beyond the mean field approximation. The rescaling of the mass quadrupole operator in the truncated shell model space is found to be almost independent of the coupling strength used in the pairing channel of the underlying mean-field theory.

A continued fraction approximation is used to calculate the RPA response function of nuclear matter. The convergence of the approximation is assessed by comparing with the numerically exact response function obtained with a typical effective finite-range interaction used in nuclear physics. It is shown that just the first order term of the expansion can give reliable results at densities up to the saturation density value.

A strong enhancement of the photon strength function at low g-ray energies was recently reported for several Mo isotopes. In order to study this enhancement further we have measured the spectra of two-step g cascades following thermal neutron capture in 95Mo. These spectra were compared with simulations of the g-decay of 96Mo performed with the aid of the DICEBOX algorithm. Simulations with a large number of model combinations of photon strength functions for E1, M1 and E2 radiation are not consistent with the strong enhancement observed in the 96Mo(3He,3He¢g)96Mo and 97Mo(3He,ag)96Mo reactions. Predictions based on combination of E1, M1 and E2 photon strength functions with no enhancement of the photon strength functions at low g-ray energies are in good agreement with the two-step g cascade data.

Direct neutron capture reactions play an important role in nuclear astrophysics and applied physics. Since for most unstable short-lived nuclei it is not possible to measure the (n, g) cross sections, (d,p) reactions have been used as an alternative indirect tool. We analyze simultaneously 48Ca(d,p)49Ca at deuteron energies 2, 13, 19 and 56 MeV and the thermal (n,g) reaction at 25 meV. We include results for the ground state and the first excited state of 49Ca. From the low-energy (d,p) reaction, the neutron asymptotic normalization coefficient (ANC) is determined. Using this ANC, we extract the spectroscopic factor (SF) from the higher energy (d,p) data and the (n, g) data. The SF obtained through the 56 MeV (d,p) data are less accurate but consistent with those from the thermal capture. We show that to have a similar dependence on the single particle parameters as in the (n, g), the (d,p) reaction should be measured at 30 MeV.

Effects of strong final-state interactions in the superscaling properties of neutral-current quasielastic neutrino cross sections are investigated using the Relativistic Impulse Approximation as guidance. First- and second-kind scaling are analyzed for neutrino beam energies ranging from 1 to 2 GeV for the cases of 12C, 16O and 40Ca. Different detection angles of the outgoing nucleon are considered in order to sample various nucleon energy regimes. Scaling of the second kind is shown to be very robust. Validity of first-kind scaling is found to be linked to the kinematics of the process. Superscaling still prevails even in the presence of very strong final-state interactions, provided that some kinematical restrains are kept, and the conditions under which superscaling can be applied to predict neutral-current quasielastic neutrino scattering are determined.

The structure of 194Ir is investigated via (n,g), (n,e-), (d,p), and ([d\vec],a) spectroscopy. The use of different methods leads to an almost complete level scheme up to high excitation energies including g-decay and spin-parity assignments. A reanalysis of the formerly published (n,g)-data was triggered by our new (d,p) and ([d\vec],a) transfer reactions. The experimental level scheme is compared to predictions using extended supersymmetry. Hereby, the classification of states was done according to quantum numbers, excitation energies and ([d\vec],a) transfer strengths. A one-to-one correspondence in excitation energies results for the 23 lowest lying theoretical states with similar structures for the experimental and calculated level schemes. The two nucleon transfer strengths show remarkable agreement. A Nilsson classification is discussed as well.

We report measurements of the cross-section and a complete set of polarization transfer coefficients for the 3He(p,n) reaction at a bombarding energy Tp = 346 MeV and a reaction angle qlab = 0°. The data are compared with the corresponding free nucleon-nucleon values on the basis of the predominance of quasi-elastic scattering processes. Significant discrepancies have been observed in the polarization transfer DLL(0°), which are presumably the result of the three-proton T = 3/2 resonance. The spin-parity of the resonance is estimated to be 1/2-, and the distribution is consistent with previous results obtained for the same reaction at Tp = 48.8 MeV.

The decay of 246Bk* nucleus, formed in entrance channel reactions 11B+235U and 14N+232Th at different incident energies, is studied by using the dynamical cluster-decay model (DCM) extended to include the deformations and orientations of nuclei. The main decay mode here is fission. The other (weaker) decay channels are the light particles evaporation (A £ 4) and intermediate mass fragments (5 £ A £ 20). All decay products are calculated as emissions of preformed clusters through the interaction barriers. The calculated fission cross sections sfiss, taken as a sum of the energetically favoured symmetric and near symmetric fragments (ACN/2±7 and A=106-110 plus complementary fragments) show an excellent agreement with experimental data at all experimental incident c.m. energies for both the reactions, except for top three energies in the case of 11B+235U reaction. The disagreement between the DCM calculations and data at higher incident c.m. energies for the 11B+235U entrance channel is associated with the presence of additional effects of non-compound, quasi-fission (qf) component, in contradiction with the measured anisotropy effects which indicate the other entrance channel 14N+232Th to contain the non-compound nucleus contribution. The prediction of two fission windows, the symmetric fission (SF) and near symmetric or heavy mass fragments (HMFs), suggests the presense of fine structure of fission fragments, which also need an experimental verification. The only parameter of model is the neck length parameter \triangle R whose value is shown to depend strongly on limiting angular momentum, which in turn depends on the use of sticking or non-sticking moment of inertia for angular momentum effects.

Antiparticle to particle ratios for identified protons, kaons and pions at Ö{sNN} = 62.4 and 200 GeV in Cu+Cu collisions are presented as a function of centrality for the midrapidity region of 0.2 < h < 1.4. No strong dependence on centrality is observed. For the á[`p] ñ/ áp ñ ratio at ápT ñ » 0.51 GeV/c, we observe an average value of 0.50±0.003(stat) 0.04_(syst) and 0.77 ±0.008(stat) 0.05_(syst) for the 10% most central collisions of 62.4 and 200 GeV Cu+Cu, respectively. The values for all three particle species measured at Ö{sNN} = 200 GeV are in agreement within systematic uncertainties with that seen in both heavier and lighter systems measured at the same RHIC energy. This indicates that system size does not appear to play a strong role in determining the midrapidity chemical freeze-out properties affecting the antiparticle to particle ratios of the three most abundant particle species produced in these collisions.

The PHENIX experiment has measured the suppression of semi-inclusive single high transverse momentum p0's in collisions at Ö{sNN} = 200 GeV. The present understanding of this suppression is in terms of energy-loss of the parent (fragmenting) parton in a dense color-charge medium. We have performed a quantitative comparison between various parton energy-loss models and our experimental data. The statistical point-to-point uncorrelated as well as correlated systematic uncertainties are taken into account in the comparison. We detail this methodology and the resulting constraint on the model parameters, such as the initial color-charge density dNg/dy, the medium transport coefficient , or the initial energy-loss parameter e0. We find that high transverse momentum p0 suppression in collisions has sufficient precision to constrain these model dependent parameters at the ± 20-25% (one standard deviation) level. These constraints include only the experimental uncertainties, and further studies are needed to compute the corresponding theoretical uncertainties.

Azimuthal angle (Df) correlations are presented for a broad range of transverse momentum (0.4 < \pt < 10 GeV/c) and centrality (0-92%) selections for charged hadrons from di-jets in Au+Au collisions at Ö{sNN} = 200 GeV. With increasing , the away-side Df distribution evolves from a broad and relatively flat shape to a concave shape, then to a convex shape. Comparisons to p+p data suggest that the away-side distribution can be divided into a partially suppressed "head" region centered at Df ~ p, and an enhanced "shoulder" region centered at Df ~ p±1.1. The spectrum for the associated hadrons in the head region softens toward central collisions. The spectral slope for the shoulder region is independent of centrality and trigger . The properties of the near-side distributions are also modified relative to those in p+p collisions, reflected by the broadening of the jet shape in Df and Dh, and an enhancement of the per-trigger yield. However, these modifications seem to be limited to pT <~4 GeV/c, above which both the hadron pair shape and per-trigger yield become similar to p+p collisions. These observations suggest that both the away- and near-side distributions contain a jet fragmentation component which dominates for pT >~5 GeV and a medium-induced component which is important for pT <~4 GeV/c. We also quantify the role of jets at intermediate and low through the yield of jet-induced pairs in comparison to binary scaled p+p pair yield. The yield of jet-induced pairs is suppressed at high pair proxy energy (sum of the magnitudes of the two hadrons) and is enhanced at low pair proxy energy. The former is consistent with jet quenching; the latter is consistent with the enhancement of soft hadron pairs due to transport of lost energy to lower .

We focus on the initial state spatial anisotropies, originating at the thermalization stage, for central collisions in relativistic heavy-ion collisions. We propose that a plot of the root mean square values of the flow coefficients Ö{[`(vn2)]}    º vnrms, calculated in a laboratory fixed coordinate system, for a large range of n from 1 to about 30, can give non-trivial information about the initial stages of the system and its evolution. We also argue that for all wavelengths l of the anisotropy (at the surface of the plasma region) much larger than the acoustic horizon size Hsfr at the freezeout stage, the resulting values of vnrms should be suppressed by a factor of order 2Hsfr/l. For non-central collisions, these arguments naturally imply a certain amount of suppression of the elliptic flow. Further, by assuming that initial flow velocities are negligible at thermalization stage, we discuss the possibility that the resulting flow could show imprints of coherent oscillations in the plot of vnrms for sub-horizon modes. For gold-gold collision at 200 GeV/A center of mass energy, these features are expected to occur for n ³ 5, with n < 4 modes showing suppression due to being superhorizon. This has strong similarities with the physics of the anisotropies of the cosmic microwave background radiation (CMBR) resulting from inflationary density fluctuations in the universe (despite important differences such as the absence of gravity effects for the heavy-ion case). It seems possible that the statistical fluctuations due to finite multiplicity may not be able to mask such features in the flow data, or, at least a non-trivial overall shape of the plot of vnrms may be inferred. In that case, the successes of analysis of CMBR anisotropy power spectrum to get cosmological parameters can be applied for relativistic heavy-ion collisions to learn about various relevant parameters at the early stages of the evolving system.

We examine the shift in the chiral condensate due to a constant electromagnetic field at O(p6) using SU(2) chiral perturbation theory and a realistic Mp = 140 MeV. We find that this value differs significantly from the value calculated using Mp = 0, while the magnitude of the two-loop correction is unclear due to the uncertainty in the experimentally determined value of the relevant L6 LEC.

The axial-vector coupling gA of a constituent quark is estimated from matching the constituent quark model to the operator product expansion in QCD in the limit of large number of colours under some assumptions. The obtained relation is gA @ Ö{7/11} » 0.80, which is in agreement with the existing model estimates.

Traditional cutoff regularization schemes of the Nambu-Jona-Lasinio model limit the applicability of the model to energy-momentum scales much below the value of the regularizing cutoff. In particular, the model cannot be used to study quark matter with Fermi momenta larger than the cutoff. In the present work an extension of the model to high temperatures and densities recently proposed by Casalbuoni, Gatto, Nardulli, and Ruggieri is used in connection with an implicit regularization scheme. This is done by making use of scaling relations of the divergent one-loop integrals that relate these integrals at different energy-momentum scales. Fixing the pion decay constant at the chiral symmetry breaking scale in the vacuum, the scaling relations predict a running coupling constant that decreases as the regularization scale increases, implementing in a schematic way the property of asymptotic freedom of quantum chromodynamics. If the regularization scale is allowed to increase with density and temperature, the coupling will decrease with density and temperature, extending in this way the applicability of the model to high densities and temperatures. These results are obtained without specifying an explicit regularization. As an illustration of the formalism, numerical results are obtained for the finite density and finite temperature quark condensate, and to the problem of color superconductivity at high quark densities and finite temperature.

I consider Compton scattering off the nucleon in the presence of T violation. I construct the Compton tensor which possesses these features and consider low energy expansion (LEX) of the corresponding amplitudes. It allows to separate out the Born contribution which only depends on the static properties of the nucleon, such as the electric charge, the mass, the magnetic moment, and the electric dipole moment (EDM). I introduce new structure constants, the T-odd nucleon polarizabilities which parametrize the unknown non-Born part. These constants describe the response of the T-violating content of the nucleon to the external quasistatic electromagnetic field. As an estimate, I provide a HBChPT calculation for these new polarizabilities and discuss the implications for the experiment.

In the present work we apply a quantum hadrodynamic effective model in the mean-field approximation to the description of neutron stars. We consider an adjustable derivative-coupling model and study the parameter influence on the dynamics of the system by analyzing the full range of values they can take. We establish a set of parameters which define a specific model that is able to describe phenomenological properties such as the effective nucleon mass at saturation as well as global static properties of neutron stars (mass and radius). If one uses observational data to fix the maximum mass for neutron stars by a specific model, we are able to predict the compression modulus of nuclear matter K = 257,2MeV.

We study the properties of strange quark matter in equilibrium with normal nuclear matter. Instead of using the conventional bag model in quark sector, we achieve the confinement by a density-dependent quark mass derived from in-medium chiral condensates. In nuclear matter, we adopt the equation of state from the Brueckner-Bethe-Goldstone approach with three-body forces. It is found that the mixed phase can occur, for reasonable confinement parameter, near the normal nuclear saturation density, and transit to pure quark matter at about 5 times the saturation. The onset of mixed and quark phases is compatible with the observed class of low-mass neutron stars, which hinders the occurrence of kaon condensation.