THE REACTION D(p, γ)He3 BELOW 50 KEV

1963 ◽  
Vol 41 (5) ◽  
pp. 724-736 ◽  
Author(s):  
G. M. Griffiths ◽  
M. Lal ◽  
C. D. Scarfe
Keyword(s):  
Angular Distribution ◽  
Cross Sections ◽  
Center Of Mass ◽  
P Wave ◽  
Laboratory System ◽  
S Wave ◽  
Mass System ◽  
S Factor ◽  
Low Energies ◽  
Γ Rays

The yield and angular distribution of the γ rays from the reaction D(p, γ) He3 have been measured with thick heavy-ice targets in the energy range from 24 kev to 48 kev. Assuming a simplified energy dependence the results have been analyzed to give cross sections for p-wave and s-wave capture. At 25 kev in the laboratory system, the cross sections are[Formula: see text]The astrophysical S-factors in the center-of-mass system below 40 kev have been found to be[Formula: see text]for E in center-of-mass kilovolts and[Formula: see text]independent of energy giving a total S-factor for low energies[Formula: see text]with E in center-of-mass kilovolts.

scholarly journals Experimental measurement of the 12C+16O fusion cross sections at astrophysical energies

2018 ◽  
Vol 178 ◽  
pp. 04008
Author(s):  
X. Fang ◽  
W. P. Tan ◽  
M. Beard ◽  
R. J. deBoer ◽  
G. Gilardy ◽  
...  
Keyword(s):  
Cross Sections ◽  
Center Of Mass ◽  
Model Calculations ◽  
Center Of Mass Energy ◽  
Pure Graphite ◽  
S Factor ◽  
Hpge Detectors ◽  
Low Energies ◽  
The University

The total cross sections of the 12C+16O fusion have been experimentally determined at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam was produced by the 5MV pelletron accelerator at the University of Notre Dame impinging on a thick ultra-pure graphite target. Protons and γ-rays were measured simultaneously in the center-of-mass energy range from 3.64 to 5.01 MeV, using strip silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. A new broad resonance-like structure is observed for the 12C+16O reaction, and a decreasing trend of its S-factor towards low energies is found.

I = 2S-wave pion scattering phase shift with two flavor full QCD

2005 ◽  
Vol 20 (15) ◽  
pp. 3476-3479
Author(s):  
◽  
T. Yamazaki
Keyword(s):  
Phase Shift ◽  
Center Of Mass ◽  
Laboratory System ◽  
Lattice Calculation ◽  
S Wave ◽  
Mass System ◽  
Pion Scattering ◽  
Scattering Phase ◽  
Volume Method ◽  
The Continuum

We present a lattice calculation of the scattering phase shift for the I = 2 S -wave pion-pion system in the continuum limit with two-flavor dynamical effect. Calculations are made at three lattice spacings, using the finite volume method proposed by Lüscher in the center of mass system, and its extension to the laboratory system by Rummukainen and Gottlieb.

scholarly journals Measurement of the angular distribution of γ-rays after neutron capture by 139La for a T-violation search

2019 ◽  
Vol 219 ◽  
pp. 09001 ◽  
Author(s):  
Takuya Okudaira ◽  
Hirohiko M. Shimizu ◽  
Masaaki Kitaguchi ◽  
Katsuya Hirota ◽  
Christopher C. Haddock ◽  
...  
Keyword(s):  
Angular Distribution ◽  
Neutron Capture ◽  
Germanium Detector ◽  
P Wave ◽  
S Wave ◽  
Proton Proton ◽  
Wave Resonance ◽  
T Violation ◽  
Γ Rays ◽  
Neutron Width

Parity violating effects enhanced by up to 106 times compared to proton-proton scattering have been observed in several neutron capture induced compound nuclei. This enhancement is explained as an interference between an s-wave and a p-wave amplitude (s-p mixing). Theory predicts that this mechanism can also enhance T-violating effects. For estimation of this enhancement in a promising candidate nucleus, we measured the angular distribution of γ-rays in the (n,γ) reaction induced in a 139La target. Experiments were performed at J-PARC, using a germanium detector array at an intense neutron beam. Analysis of the observed angular dependence around the 0.74 eV p-wave resonance allowed us to determine the ratio of the partial p-wave neutron width to the total neutron width in the entrance channel of the compound nucleus. We also report our development of a 3He spin filter needed as an epithermal-neutron polarizer for the T-violation search.

scholarly journals Testing Compound Nucleus Hypothesis Across the 17O Nucleus Excitation

2019 ◽  
Vol 211 ◽  
pp. 02001 ◽  
Author(s):  
Aloys Nizigama ◽  
Pierre Tamagno ◽  
Olivier Bouland
Keyword(s):  
Cross Section ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Center Of Mass ◽  
Ground States ◽  
Mass System ◽  
Resonance Parameters ◽  
Second Stage ◽  
Reference Framework ◽  
Kinetic Transformation

The excited compound nucleus 17O* has been studied over (n,α) and (α,n) cross sections modelling, respectively for 16O and 13C targets in their ground states. The modelling is fulfilled within the Reich-Moore formalism. We were able to calculate the (α,n) cross section by two separate ways: the direct kinematic standard route and by inversion of the (n,α) cross section using the compound nucleus hypothesis. Resonance parameters of the resolved resonance range (0 to 6 MeV) were borrowed from the CIELO project. In a first stage, the modelling is carried out in the referential of the incident particle (either way neutron or α) requesting conversion of the CIELO neutron-type resonance parameters to the α-type. In a second stage, the implementation is uniquely designed in the center of mass system of the excited compound nucleus. The resonance parameters are thus converted in that unique reference framework. The present investigation shows the consistency of the kinetic transformation that relies on the compound nucleus hypothesis.

VECTOR CORRELATIONS AND PRODUCT POLARIZATIONS IN THE N(2D) + D2 → ND + D REACTIVE SYSTEM

2012 ◽  
Vol 11 (05) ◽  
pp. 1005-1018 ◽  
Author(s):  
SHANSHAN NIE ◽  
TIANSHU CHU
Keyword(s):  
Angular Distribution ◽  
Cross Sections ◽  
Energy Surface ◽  
Center Of Mass ◽  
Classical Trajectory ◽  
Reactive System ◽  
Angle Distribution ◽  
Polar Form ◽  
Generalized Polarization ◽  
Vector Correlations

The vector correlations between products and reagents of the N (2D) + D 2 reaction are investigated by employing quasi-classical trajectory (QCT) calculation on the accurate DMBE potential energy surface (PES) of the 2A″ state. Stereo-dynamic quantities, including the four generalized polarization-dependent differential cross-sections (PDDCSs), the angular distribution P(θr), the dihedral-angle distribution P(φr), as well as the product rotational angular distribution in the polar form of P(θr, φr), are calculated in the center-of-mass (CM) frame. The results indicate that the product rotational angular momentum j′ not only aligns along the y-axis, but also orients to the negative direction of the y-axis. The isotope effect in the context of chemical stereo-dynamics and influences of different versions of ground-state PESs on vector correlations are shown and discussed.

scholarly journals Very high energy cosmic gamma rays

1965 ◽  
Vol 23 ◽  
pp. 253-258
Author(s):  
M. Libber ◽  
S. N. Milford ◽  
M. S. Spergel
Keyword(s):  
Pion Production ◽  
Center Of Mass ◽  
Cosmic Ray ◽  
High Energy ◽  
Mass System ◽  
Proton Proton ◽  
Production Spectrum ◽  
Very High Energy ◽  
Γ Rays ◽  
Γ Ray

Collisions of high energy cosmic rays with intergalactic gas produce various secondaries, including neutral pions that decay into high energy γ rays. The Landau-Milekhin hydrodynamical model for proton-proton collisions is used to calculate the pion production spectrum corresponding to cosmic γ rays of energy above 10 Gev. A source function for these high energy γ rays in space is found by combining the pion production and decay spectra with the primary cosmic ray proton flux. The resulting γ ray spectrum follows a different power law than spectra based upon the usual assumption of a line spectrum for the pions in the center of mass system of the colliding protons. The high energy γ ray intensity in space is calculated for a simple model universe. By comparison with previous estimates for the proton photoproduction process, it is found that proton-proton and proton-photon collisions appear to contribute about the same order of magnitude to the intergalactic γ ray intensity above ∼1016 eV.

scholarly journals QED ON THE GROENEWOLD–MOYAL PLANE

2009 ◽  
Vol 24 (25n26) ◽  
pp. 4789-4804 ◽  
Author(s):  
A. P. BALACHANDRAN ◽  
A. PINZUL ◽  
B. A. QURESHI ◽  
S. VAIDYA
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Center Of Mass ◽  
Pauli Principle ◽  
Mass System ◽  
Tree Approximation ◽  
Moyal Plane ◽  
Interaction Term

We investigate a version of noncommutative QED where the interaction term, although natural, breaks the spin-statistics connection. We calculate e- + e- → e- + e- and γ + e- → γ + e- cross-sections in the tree approximation and explicitly display their dependence on θμν. Remarkably the zero of the elastic e- + e- → e- + e- cross-section at 90° in the center-of-mass system, which is due to Pauli principle, is shifted away as a function of θμν and energy.

scholarly journals Scattering Cross Sections in Argon from Electron Transport Parameters

1982 ◽  
Vol 35 (1) ◽  
pp. 35 ◽  
Author(s):  
GN Haddad ◽  
TF O'Malley
Keyword(s):  
Phase Shift ◽  
Cross Section ◽  
Cross Sections ◽  
Lateral Diffusion ◽  
Phase Shifts ◽  
P Wave ◽  
Transport Parameters ◽  
S Wave ◽  
Wave Phase ◽  
Range Theory

Previously determined experimental drift velocities Vdr and ratios of lateral diffusion coefficient to mobility DT/µ have been refitted directly with a three parameter modified effective range theory (MER T) representation of the S wave phase shift, a one parameter fit to the P wave phase shift and fixed higher partial wave phase shifts. The MERT representation now extends to 1·0 eV, a threefold extension of the energy range of the MERT fit reported by Milloy et al. (1977). The total cross section derived from the phase shifts is also reported, together with the differential cross section at 1·0 eV which is compared with a previous experimental determination.

Vacuum polarization and D-wave α−α scattering

1969 ◽  
Vol 47 (1) ◽  
pp. 113-115 ◽  
Author(s):  
Mark W. Kermode
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Vacuum Polarization ◽  
Center Of Mass ◽  
Phase Shifts ◽  
Differential Cross Sections ◽  
Wave Phase ◽  
Low Energies ◽  
D Wave

The D-wave phase shifts for α−α scattering at low energies are obtained from (i) new analyses of the differential cross sections and (ii) the effects of vacuum polarization. The results are −0.4° (−0.4°), −0.2° (−0.4°), +0.2° (−0.4°), −0.2° (−0.2°), and 0.3° (0.2°) for the center-of-mass energies 0.3, 0.425, 0.5, 0.75, and 1.0 MeV, respectively. It is felt that these results are significant.

scholarly journals NEW RESULTS ON THE pd→3Heη PRODUCTION NEAR THRESHOLD

2005 ◽  
Vol 20 (02n03) ◽  
pp. 643-645 ◽  
Author(s):  
H.-H. ADAM ◽  
A. KHOUKAZ ◽  
N. LANG ◽  
T. LISTER ◽  
R. SANTO ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Final State Interaction ◽  
Center Of Mass ◽  
Meson Production ◽  
Angular Distributions ◽  
Final State ◽  
Mass System ◽  
Total Cross Sections ◽  
Model Predictions

Measurements on the η meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY (Jülich). Here we present preliminary results on total and differential cross sections for the pd→3 He η reaction at five excess energies between Q=5.1 and Q=40.6 MeV. The obtained angular distributions for the emitted η mesons in the center of mass system expose a transition from an almost isotropic emission to a highly anisotropic distribution. The extracted total cross sections support a strong η-3 He final state interaction and will be compared with model predictions.

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