Search results for "Nucleon"

Two-body Mechanisms in Pion Scattering and Pion Photoproduction on the Trinucleon

1995

A breakdown of the Impulse Approximation is studied in pion photoproduction and pion charge exchange on 3He at high momentum transfers. The usual DWIA formalism with Faddeev wave functions which works well for small momentum transfers deviates from experimental measurements by up to two orders of magnitude for Q 2 > 6 fm−2. It is found that the explicit inclusion of two-body mechanisms, where the photon or pion is absorbed on one nucleon and the pion is emitted from another nucleon removes most of the disagreement with the data.

β-decay of [sup 23]Al and nova nucleosynthesis

2010

We have studied the β‐decay of 23Al with a novel detector setup at the focal plane of the MARS separator at the Texas A&M University to resolve existing controversies about the proton intensities of the IAS in 23Mg and to determine the absolute proton branching ratios by combining our results to the latest γ‐decay data. Experimental technique, results and the relevance for nova nucleosynthesis are discussed.

The effect of nonlocality of nucleon-nucleon potential on the two-body sum rules

1971

The Mainz Microtron MAMI

2008

An overview of the Mainz Microtron MAMI is given. The main goal is to study the low-energy structure of hadrons. Typical examples are measurements of nucleon form factors, the polarizability of nucleons and pions and the detailed study of the excitation spectrum of nucleons. At present, an energy upgrade to 1.5 GeV (MAMI C) is close to completion. The status of the new accelerator section (HDSM) and experimental setups are briefly described and an outlook to the planned physics program is given.

Elliptic and Hexadecapole Flow of Charged Hadrons inAu+AuCollisions atsNN=200  GeV

2010

Differential measurements of the elliptic (upsilon(2)) and hexadecapole (upsilon(4)) Fourier flow coefficients are reported for charged hadrons as a function of transverse momentum (p(T)) and collision centrality or number of participant nucleons (N-part) for Au + Au collisions at root s(NN) = 200 GeV/ The upsilon(2,4) measurements at pseudorapidity vertical bar eta vertical bar <= 0.35, obtained with four separate reaction-plane detectors positioned in the range 1.0 < vertical bar eta vertical bar < 3.9, show good agreement, indicating the absence of significant Delta eta-dependent nonflow correlations. Sizable values for upsilon(4)(p(T)) are observed with a ratio upsilon(4)(p(T), N-part)/…

Migration of Nuclear Shell Gaps Studied in thed(Ne24,pγ)Ne25Reaction

2010

The transfer of neutrons onto 24Ne has been measured using a reaccelerated radioactive beam of 24Ne to study the (d,p) reaction in inverse kinematics. The unusual raising of the first 3/2+ level in 25Ne and its significance in terms of the migration of the neutron magic number from N=20 to N=16 is put on a firm footing by confirmation of this state's identity. The raised 3/2+ level is observed simultaneously with the intruder negative parity 7/2- and 3/2- levels, providing evidence for the reduction in the N=20 gap. The coincident gamma-ray decays allowed the assignment of spins as well as the transferred orbital angular momentum. The excitation energy of the 3/2+ state shows that the estab…

Interpretation of the High-Energy ProcessesO16(γ,p0)N15andO16(γ,n0)O15

1978

Calculations based on a two-nucleon ($n\ensuremath{-}p$) absorption mechanism show that the form factor of the residual nucleus plays an important role in determining the shape of the photoproduction cross section in a wide energy range $60 \mathrm{MeV}l~{E}_{\ensuremath{\gamma}}l~300 \mathrm{MeV}$.

Modeling moderated proportional neutron counters using the Geant4 toolkit and the application to detection of fast neutron burst

2014

Scattering of Strongly Interacting Particles on Nuclei

1996

This chapter deals with the interaction of strongly interacting particles (hadrons) with nuclei, at low and intermediate energies. The hadronic projectiles are used as probes of nuclear properties and of the hadron-nucleon interaction in the nuclear medium, and they are selected accordingly. We discuss mainly the case of pions, to some extent also kaons, because of the specific properties of the pion-(kaon)-nucleon system. Some of the methods and results can also be applied to nucleons if these are chosen to be projectiles, but we do not go into the full complexity of the spin analysis of the nucleon-nucleon system. In this sense this field is distinct from the conventional topic of nuclear…

Approaching theN=82shell closure with mass measurements of Ag and Cd isotopes

2010

Mass measurements of neutron-rich Cd and Ag isotopes were performed with the Penning trap mass spectrometer ISOLTRAP. The masses of ${}^{112,114\ensuremath{-}124}$Ag and ${}^{114,120,122\ensuremath{-}124,126,128}$Cd, determined with relative uncertainties between $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$ and $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$, resulted in significant corrections and improvements of the mass surface. In particular, the mass of $^{124}\mathrm{Ag}$ was previously unknown. In addition, other masses that had to be inferred from $Q$ values of nuclear decays and reactions have now been measured directly. The analysis includes various mass…