Search results for "Nucleon"
showing 10 items of 1041 documents
N* resonances in the ππNsystem
2010
We have solved the Faddeev equations for the ππN system and coupled channels resulting into the dynamical generation of two N* , N* (1710) and N* (2100), and one ∆ states, ∆ (1910), all of them with J P = 1/2+ . In addition, signatures for a new N* resonance with JP = 1/2+ are found around at an energy of 1920 MeV.
LOCAL STRONG AND COULOMB POTENTIALS IN THE THREE-NUCLEON SYSTEM
1976
Publisher Summary This chapter focuses on local strong and Coulomb potentials in the three-nucleon system. Attempts to use local potentials in three-nucleon calculations with the Faddeev equations are impeded by the fact that for increasing energies contributions from higher and higher subsystem, angular momentum states become important, which quickly make the system of coupled equations unwieldy. However, if long-range interactions such as the Coulomb potential were added, such a procedure would not be useful at all. Several approaches exist that deal with the problems arising from the infinite range of the latter. In the work of Noble and Bencze, the Faddeev equations are modified so that…
SYSTEMATICAL MULTIPARTICLE THEORY AND ITS APPLICATION TO THE FOUR-NUCLEON PROBLEM
1972
Publisher Summary This chapter discusses the systematical multiparticle theory and its application in the four-nucleon problem. The chapter describes the structure of the 2- body and 3-body equations and shows that the generalization to n particles can be accomplished in a natural way. It is a characteristic feature of this approach that the kernel of the occurring integral equations is built up by all subsystem transition operators in an explicit way. One of the important features of the 3-body theory is also achieved in the n-body formalism. This enables the application of the quasiparticle concept in a direct way. The 2-body problem is completely determined by the solution of the Lippman…
Magicity of theN68iSemidouble-Closed-Shell Nucleus Probed by Gamow-Teller Decay of the Odd-ANeighbors
1999
The particle-hole excitations through the $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}40$ subshell around ${}^{68}\mathrm{Ni}$ have been studied by the $\ensuremath{\beta}$ decay of ${}^{69}\mathrm{Co}$ and ${}^{69}\mathrm{Ni}$. The half-life of ${}^{69}\mathrm{Co}$ was measured to be 0.22(2) s, and a new $\ensuremath{\beta}$-decaying isomer with a half-life of 3.5(5) s was identified in ${}^{69}\mathrm{Ni}$. From the decay of the ${}^{69}\mathrm{Ni}$ isomer a 9(4)% mixing of the $\ensuremath{\pi}{p}_{3/2}^{+1}\ensuremath{\nu}{p}_{1/2}^{\ensuremath{-}2}\ensuremath{\nu}{g}_{9/2}^{+2}$ configuration into the ground state of ${}^{69}\mathrm{Cu}$ can be deduced. Significant polarizatio…
Pseudorapidity Density of Charged Particles inp+PbCollisions atsNN=5.02 TeV
2013
The charged-particle pseudorapidity density measured over four units of pseudorapidity in nonsingle-diffractive p + Pb collisions at a center-of-mass energy per nucleon pair root s(NN) = 5.02 TeV is presented. The average value at midrapidity is measured to be 16.81 +/- 0.71 (syst), which corresponds to 2.14 +/- 0.17 (syst) per participating nucleon, calculated with the Glauber model. This is 16% lower than in nonsingle-diffractive pp collisions interpolated to the same collision energy and 84% higher than in d + Au collisions at root s(NN) = 0.2 TeV. The measured pseudorapidity density in p + Pb collisions is compared to model predictions and provides new constraints on the description of …
Multi-nucleon transfer reactions at ion catcher facilities : a new way to produce and study heavy neutron-rich nuclei
2020
Abstract The production of very neutron-rich nuclides heavier than fission fragments is an ongoing experimental challenge. Multi-nucleon transfer reactions (MNT) have been suggested as a method to produce these nuclides. By thermalizing the reaction products in gas-filled stopping cells, we can deliver them as cooled high-quality beams to decay, laser and mass spectrometry experiments. High precision mass spectrometry will allow for the first time to universally and unambiguously identify the atomic and proton numbers of the ions produced in MNT reactions. In this way their ground and isomeric state properties can be studied in high-precision measurements. In experiments at IGISOL, Finland …
Baryon chiral perturbation theory
2009
We provide a short introduction to the one-nucleon sector of chiral perturbation theory and address the issue of power counting and renormalization. We discuss the infrared regularization and the extended on-mass-shell scheme. Both allow for the inclusion of further degrees of freedom beyond pions and nucleons and the application to higher-loop calculations. As applications we consider the chiral expansion of the nucleon mass to order ${\cal O}(q^6)$ and the inclusion of vector and axial-vector mesons in the calculation of nucleon form factors. Finally, we address the complex-mass scheme for describing unstable particles in effective field theory.
β-decay measurements ofA≃ 70 − 110 r-process nuclei at the National Superconducting Cyclotron Laboratory
2011
The present paper reports on several r-process motivated β-decay experiments undertaken at the National Superconducting Cyclotron Laboratory. β-decay half-lives and β-delayed neutron-emission probabilities were measured for nuclei around the r-process A = 70–80 and A = 90 – 110 mass regions. The data are discussed on the basis of quasi-random phase approximation calculations. The emphasis is made on the impact of these data upon calculations of r-process abundances.
Emission of fragments in Ca+Ca reaction at 25 MeV/nucleon
2013
We discuss experimental data concerning 40,48Ca+ 40,48Ca reactions at 25 MeV/nucleon; the 4π multi-detector Chimera has been used as detection device. Effects that can be attributed to the neutron to proton ratios (N/Z) degree of freedom have been investigated. From the analysis of experimental data it seems that the neutron richness of the interacting system plays an important role on the evolution of fusion-like sources formed in semi-central collisions. In particular, it is observed that the larger is the neutron content and the larger is the emission of heavy residues. Experimental data have been compared with CoMD-II model calculations; a moderately stiff symmetry energy should be used…
The polarized electron-nucleon collider project ENC at GSI/FAIR
2011
The ENC project attempts to realize an electron-nucleon collider at the upcoming Facility for Antiproton and Ion Research FAIR at GSI Darmstadt by utilizing the antiproton high-energy storage ring HESR for polarized proton and deuteron beams. The addition of a 3.3 GeV storage ring for polarized electrons will enable electron-nucleon collisions up to a center-of-mass energy of - s - 14 GeV. In such a configuration peak luminosities in the range of L = 10(32) to 10(33)cm(-')(2)s(-')(1) are feasible . Beam-beam effects in a space-charge dominated regimes in conjunction with high-energy electron cooling represents one of the main challenges for this project. In this paper beam- and spin dynamic…