Time Reversal in Nuclear Interactions

Henley, Ernest M.; Jacobsohn, Boris A.

doi:10.1103/physrev.108.502

Cited by 17 publications

(3 citation statements)

References 19 publications

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“…To check experimentally the detailed balance conditions it is necessary to deal with a complex reaction that can be formally equilibrated without detailed balance. If not, then one tests not the detailed balance but just the equilibrium condition as it was mentioned in [25].…”

Section: A Bit Of Historymentioning

confidence: 99%

Local equivalence of reversible and general Markov kinetics

Gorban

2013

Physica A: Statistical Mechanics and its Applications

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We consider continuous-time Markov kinetics with a finite number of states and a positive equilibrium P * . This class of systems is significantly wider than the systems with detailed balance. Nevertheless, we demonstrate that for an arbitrary probability distribution P and a general system there exists a system with detailed balance and the same equilibrium that has the same velocity dP/dt at point P . The results are extended to nonlinear systems with the generalized mass action law.

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Section: A Bit Of Historymentioning

confidence: 99%

Local equivalence of reversible and general Markov kinetics

Gorban

2013

Physica A: Statistical Mechanics and its Applications

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“…7 We have compared e and P for hydrogen, lithium, beryllium, and aluminum, chosen for their high spin-tomass ratios, since a failure of e=P in spin-zero nuclei would necessarily violate parity conservation. 5 No measurements of P have previously been performed for these elements.…”

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confidence: 99%

“…It has been estimated that in strong interactions, present experimental data set an upper limit of 10-20% to the relative strength of forces which are noninvariant with respect to time reversal. 7 We have compared e and P for hydrogen, lithium, beryllium, and aluminum, chosen for their high spin-tomass ratios, since a failure of e=P in spin-zero nuclei would necessarily violate parity conservation. 5 No measurements of P have previously been performed for these elements.…”

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confidence: 99%

Time-Reversal Invariance in Nuclear Scattering

1958

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W E report here some experimental tests of timereversal invariance, or of parity conservation, or both, in high-energy nuclear scattering. The work was carried out because of the discovery of the failure of parity conservation in weak interactions. 1 If parity conservation is assumed, 2 which recent experiments have shown to be a good approximation for strong interactions, 3 then one can show quite straightforwardly that time-reversal invariance requires the equality of P and e, 4,5 where P is the polarization produced in the scattering of unpolarized protons and e is the asymmetry produced when fully polarized protons are scattered. Furthermore, in the case of p-p scattering, it has been shown 6 that, at angles near 45° cm, \P-e\ is maximum and of the same order of magnitude as the ratio between the coefficients of the two parts of the scattering matrix which are noninvariant and invariant, respectively, under time reversal. It has been estimated that in strong interactions, present experimental data 100 Ponde 80\ 60\ 40[ 20\ I Li J Polarizothn T I Asymmetry I I. * : i 1^ [1 ,i i H . . ' fl • 1 I 10° 15° 20° 25° a JT 30° *& FIG. 1. Asymmetry (energy 155 Mev, angular resolution 0.6°) and polarization (energy 180 Mev, angular resolution 0.6°) for lithium. FIG. 2. Asymmetry (energy 155 Mev, angular resolution 0.5° for 06°; 0-9° elsewhere) and polarization (below 15°; energy 156 Mev, angular resolution 1.0°; above 15°; energy 175 Mev, angular resolution 1.3°) for aluminum.set an upper limit of 10-20% to the relative strength of forces which are noninvariant with respect to time reversal. 7 We have compared e and P for hydrogen, lithium, beryllium, and aluminum, chosen for their high spin-tomass ratios, since a failure of e=P in spin-zero nuclei would necessarily violate parity conservation. 5 No measurements of P have previously been performed for these elements. Values of e are available near our energy only for hydrogen. We have measured P for hydrogen, P and e separately for lithium and aluminum, and e/P for beryllium and aluminum, using the unpolarized 185-Mev external beam of the Uppsala synchrocyclotron. All the measurements of e and e/P were made with the range equipment of Alphonce, Johansson, and Tibell, 8 and those of P with the analyzer magnet setup described by Hillman, Johansson, and Tyren. 9 The values of e/P for beryllium and aluminum were determined in the standard double-scattering arrangement at one angle only, 14.2° in the lab system, by interchanging first and second targets, one of which was always carbon. All targets were 15 Mev thick, and a first-order correction was made for the energy degradation by having the second scattering take place at (177.5/162.5)^X14.2°= 14.8°. In one case the measured asymmetry is ei = Pce v and in the other ez = P v ec, where v stands for either Be or Al. However, carbon has spin zero, so if parity is conserved ec=Pc, and so ei/e2=e y /P v .The values of P for hydrogen were measured with polyethylene, but the good energy resolution of the magnet used meant that th...

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Near-harmonic structure and level similarities in Fe56, Fe58 and Ni60

1958

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Near-harmonic structure is known to exist in Fe 58, and an investigation was undertaken to determine whether this structure is also present in Fe aG, and Ni so. In the case of Fe ~", no second 2 + state with the desired energy or de-excitation characteristics had been reported by previous investigators and a search for a small excitation of such a level from the decay of Mn s6 is described. The results are inconclusive although some evidence for its existence is presented. Our investigation of the MnSG--Fe 56 decay reveals the presence of an additional beta branch to a 2 + level at 3.34 Mev in Fe 56. The results of the angular correlation measurements on the cascade gamma rays from this and other Ievels are given. The stopover transitions are found to be mostly Mt radiation and hence not of the near-harmonic type. In the case of Ni 6~ the measured angular correlation functions for the 0.85--t.33 and t.76--1-33 Mev cascades initiated from the decay of Cu 6~ are reported. For the former cascade, the results indicate that the stopover transition is largely E2 radiation, but the experimentaldifiicnlties pre~ent a more quantitative statement. The presence of this type of radiation, together with a stopover to crossover intensity ratio of t 5, imply the existence of near-harmonic structure in Ni "~ The angular correlation function for the latter cascade is found to be nearly identical to that of the corresponding cascade in Fe as which lends weight to the contention that there exist level similarities in these nuclei. Additional evidence for these similarities is also presented.

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Time Reversal in Nuclear Interactions

Cited by 17 publications

References 19 publications

Local equivalence of reversible and general Markov kinetics

Local equivalence of reversible and general Markov kinetics

Time-Reversal Invariance in Nuclear Scattering

Near-harmonic structure and level similarities in Fe56, Fe58 and Ni60

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