Pion–pion scattering in a model satisfying crossing symmetry, analyticity, and approximate unitarity

1976 ◽  
Vol 54 (10) ◽  
pp. 1022-1033
Author(s):  
D. H. Boal ◽  
J. W. Moffat
Keyword(s):  
Phase Shift ◽  
Energy Region ◽  
Detailed Comparison ◽  
Phase Shifts ◽  
Low Energy ◽  
Pion Scattering ◽  
Crossing Symmetry ◽  
Mandelstam Analyticity ◽  
Good Agreement

Phase shifts for π–π scattering are obtained from a model satisfying Mandelstam analyticity, exact crossing symmetry, and approximate unitarity in the range 2mπ ≤ s1/2 ≤ 1.3 GeV. The low energy region is dominated by the ρ, ε, and S* poles; the δ00 phase shift is in good agreement with the data obtained by Protopopescu et al. A detailed comparison is made with the available world's data on π–π scattering.

Range and Range Straggling of 97 keV 224Ra Particles in Gases

1971 ◽  
Vol 49 (8) ◽  
pp. 1004-1017 ◽  
Author(s):  
J. Leon ◽  
N. H. Steiger-Shafrir
Keyword(s):  
High Precision ◽  
Energy Region ◽  
Detailed Comparison ◽  
Nuclear Stopping ◽  
Range Distribution ◽  
Medium Mass ◽  
Gaseous Media ◽  
Range Determination ◽  
Good Agreement

High precision range and straggling measurements of 96.5 keV224Ra α-disintegration recoil particles in various gaseous media are described. Special emphasis is placed on the development of a uniform and non-degrading recoil source in order to insure accurate range determination and to prevent broadening of the straggling results by the source. Excellent symmetry for the range distribution curves for all, even the heavy gases, was obtained. The performance of the measurements in gases, where successive collisions can be considered as uncorrelated, enabled a detailed comparison with theoretical treatments of the nuclear stopping mechanism, dominating in this energy region. The results obtained were compared with the Lindhard theory and show good agreement, especially for the medium mass gases.

INTERNAL BREMSSTRAHLUNG SPECTRUM OF 204Tl IN THE X-RAY REGION

2001 ◽  
Vol 10 (03) ◽  
pp. 237-243 ◽  
Author(s):  
M. K. RAGHAVENDRA ◽  
C. R. RAMASWAMY
Keyword(s):  
Energy Region ◽  
Low Energy ◽  
Spectral Intensity ◽  
Bremsstrahlung Spectrum ◽  
Internal Bremsstrahlung ◽  
X Ray ◽  
Good Agreement

The internal Bremsstrahlung spectrum from 204 Tl has been measured, using magnetic deflector method, in the X-ray region. The corrected spectral intensity is compared with the Coulomb-corrected KUB theory in the energy region of 10 to 30 keV. The good agreement between experiment and theory in this energy region, suggests that "detour effects" are negligible in the low energy region.

Application of Moffat's Model to η → 3π and K → 3π Decays

1972 ◽  
Vol 50 (12) ◽  
pp. 1346-1349
Author(s):  
Donald Smith ◽  
Charles Picciotto
Keyword(s):  
Energy Region ◽  
Low Energy ◽  
Fair Agreement ◽  
Mandelstam Representation ◽  
Regge Behavior ◽  
Crossing Symmetry ◽  
Low Energies

Moffat's model for meson–meson scattering, satisfying the Mandelstam representation, crossing symmetry, and Regge behavior, is applied to η → 3π and K → 3π decays. It is found that agreement with the data is excellent when the model is used with Lovelace's trajectory, but not as good with Moffat's trajectory. The model is also applied to the process [Formula: see text], and fair agreement is found in the low energy region; however, since the model is unitary only at low energies, no strong conclusions can be reached in this case.

Computational Study on the Kinetics and Mechanisms of Unimolecular Reactions of (Z)-(Z)-N-(λ5-phosphanylidene) Formohydrazonic Formic Anhydride: Intramolecular aza-Wittig Reaction in Competition with Mumm Rearrangement

2020 ◽  
Vol 17 (11) ◽  
pp. 884-889
Author(s):  
Somayeh Mirdoraghi ◽  
Hamed Douroudgari ◽  
Farideh Piri ◽  
Morteza Vahedpour
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Wittig Reaction ◽  
Computational Study ◽  
Single Step ◽  
Low Energy ◽  
Coupled Cluster ◽  
Unimolecular Reaction ◽  
Single Step Reaction ◽  
Good Agreement

For (Z)-(Z)-N-(λ5-phosphanylidene) formohydrazonic formic anhydride, Aza-Wittig reaction and Mumm rearrangement are studied using both density functional and coupled cluster theories. For this purpose, two different products starting from one substrate are considered that are competing with each other. The obtained products, P1 and P2, are thermodynamically favorable. The product of the aza-Wittig reaction, P1, is more stable than the product of Mumm rearrangement (P2). For the mentioned products, just one reliable pathway is separately proposed based on unimolecular reaction. Therefore, the rate constants based on RRKM theory in 300-600 K temperature range are calculated. Results show that the P1 generation pathway is a suitable path due to low energy barriers than the path P2. The first path has three steps with three transition states, TS1, TS2, and TS3. The P2 production path is a single-step reaction. In CCSD level, the computed barrier energies are 14.55, 2.196, and 10.67 kcal/mol for Aza-Wittig reaction and 42.41 kcal/mol for Mumm rearrangement in comparison with the corresponding complexes or reactants. For final products, the results of the computational study are in a good agreement with experimental predictions.

LONG-RANGE CORRELATIONS IN THE PHASE-SHIFTS OF NUMERICAL SIMULATIONS OF BIOCHEMICAL OSCILLATIONS AND IN EXPERIMENTAL CARDIAC RHYTHMS

1999 ◽  
Vol 07 (02) ◽  
pp. 113-130 ◽  
Author(s):  
I. M. DE LA FUENTE ◽  
L. MARTINEZ ◽  
J. M. AGUIRREGABIRIA ◽  
J. VEGUILLAS ◽  
M. IRIARTE
Keyword(s):  
Phase Shift ◽  
Periodic Solutions ◽  
Long Range ◽  
Phase Shifts ◽  
Long Range Correlations ◽  
Rescaled Range ◽  
Biochemical Oscillations ◽  
Phase Shift Data ◽  
Relationship Of ◽  
The Relationship

In biochemical dynamical systems during each transition between periodical behaviors, all metabolic intermediaries of the system oscillate with the same frequency but with different phase-shifts. We have studied the behavior of phase-shift records obtained from random transitions between periodic solutions of a biochemical dynamical system. The phase-shift data were analyzed by means of Hurst's rescaled range method (introduced by Mandelbrot and Wallis). The results show the existence of persistent behavior: each value of the phase-shift depends not only on the recent transitions, but also on previous ones. In this paper, the different kind of periodic solutions were determined by different small values of the control parameter. It was assessed the significance of this results through extensive Monte Carlo simulations as well as quantifying the long-range correlations. We have also applied this type of analysis on cardiac rhythms, showing a clear persistent behavior. The relationship of the results with the cellular persistence phenomena conditioned by the past, widely evidenced in experimental observations, is discussed.

Comment on ‘The screening effect of D–D fusion in Sm in sub-low energy region (≤20 keV)’

2008 ◽  
Vol 35 (6) ◽  
pp. 068001
Author(s):  
T S Wang ◽  
Z Yang ◽  
H Yunemura ◽  
A Nakagawa ◽  
H Y Lv ◽  
...  
Keyword(s):  
Energy Region ◽  
Low Energy ◽  
Screening Effect

Perturbative QCD effects in the non-perturbative low energy region

1985 ◽  
Vol 165 (1-3) ◽  
pp. 187-192 ◽  
Author(s):  
Hector R. Rubinstein ◽  
Håkan Snellman
Keyword(s):  
Perturbative Qcd ◽  
Energy Region ◽  
Low Energy
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