Reinforcement of $K^0_{S}$ regeneration in the model with Hermitian Hamiltonian
The simple model of the $K^0_{S}$ regeneration with the Hermitian Hamiltonian is proposed. The increase of regeneration takes place.
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arXiv subjects
V. I. Nazaruk
Publications and source records attributed to V. I. Nazaruk.
Limit on the neutron-antineutron transitions in the alternative models
We summarize our study of the neutron-antineutron transition in medium and nuclei in the framework of the field-theoretical approach. The models based on the diagram technique for direct reactions, potential description of antineutron-medium interaction are considered as well. The lower limit on the free-space neutron-antineutron oscillation time $τ$ is in the range: $10^{16}\; {\rm yr}>τ>1.2\cdot 10^{9}\; {\rm s}$.
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On the critical examination of the "field-theoretical approach" to the neutron-antineutron oscillations in nuclei
We briefly outline the models of the $n\bar{n}$ transition in nuclei and analyse a well known calculation based on diagram technique published in 1992 and repeated recently by V. Kopeliovich and I. Potashnikova.
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$n\bar{n}$ conversion in finite nuclei
The new model of $n\bar{n}$ transitions in nuclei based on unitary $S$-matrix is considered. The $|in>$-state of nucleus is described by single-particle shell model. The dynamical process part is calculated by means of field-theoretical approach with finite time interval. The lower limit on the free-space $n\bar{n}$ oscillation time $τ_{\rm min}$ is in the range $10^{16}\; {\rm yr}>τ_{\rm min}>1.2\cdot 10^{9}\; {\rm s}$. \end{abstract}
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On the suppression of the $n\bar{n}$ transitions in medium
The new model of $n\bar{n}$ transitions in the medium based on unitary $S$-matrix is considered. The time-dependence and corrections to the model are studied. The lower limit on the free-space $n\bar{n}$ oscillation time $τ$ is in the range $10^{16}\; {\rm yr}>τ>1.2\cdot 10^{9}\; {\rm s}$
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$n\bar{n}$ transitions in medium
The models of $n\bar{n}$ transitions in the medium based on unitary $S$-matrix are considered. The time-dependence and corrections to the models are studied. The lower limits on the free-space $n\bar{n}$ oscillation time are obtained as well.
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Qualitative aspects of the models of $n\bar{n}$ transition in nuclei
We briefly outline the present state of the $n\bar{n}$ transition problem and compare two alternative models.
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Comment to "On the field-theoretical approach to the neutron-antineutron oscillations in nuclei"
We briefly outline the present state of the $n\bar{n}$ transition problem and analyse the recent manuscript of the Vladimir Kopeliovich (arXiv: 0912.5065).
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On the multistep processes in the nuclei
The intermediate-state interaction and structure of amplitudes of complicated processes in medium (decays, reactions and the $n\bar{n}$ transitions) are studied. It is proposed to use the branching ratio of channels of free-space hadron-nucleon interaction as a test in the construction and verification of the models. The corresponding formulas for the processes in the medium are obtained. The connection between particle self-energy and amplitudes of subprocesses are analyzed as well.
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On the $n\bar{n}$ transitions in the medium
The corrections to the model of $n\bar{n}$ transitions in the medium and additional baryon-number-violating processes are considered. We focus on the time-dependence since it is different for the $n\bar{n}$ transition followed by annihilation (basic process) and processes mentioned above.
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Low-density limit as a test for the models of complicated processes in the nuclei
We propose to use the branching ratio of channels of free-space hadron-nucleon interaction as a test in the construction and verification of the models of complicated processes in the nuclei. The particle self-energy and amplitudes of subprocesses are studied as well.
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Absorption in the final state in reactions and decays in the medium
The role of strong absorption of particles in intermidiate and final states has been considered. The range of applicability of phenomenological model of absorption has been studied. This model is nonuniversal. Its applicability depends on the type of interaction Hamiltonian and matrix element used. We also demonstrate that the violation of the unitarity condition can produce a qualitative error in the results. The absorption (decay) in the final state does not tend to suppress the total process probability as well as the probability of the channel corresponding to absorption. This is true for the reactions, decays and $n\bar{n}$ conversion in the medium.
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Field-theoretical approach to particle oscillations in absorbing matter
The $ab$ oscillations in absorbing matter are considered. The standard model based on optical potential does not describe the total $ab$ transition probability as well as the channel corresponding to absorption of the $b$-particle. We calculate directly the off-diagonal matrix element in the framework of field-theoretical approach. Contrary to one-particle model, the final state absorption does not tend to suppress the channels mentioned above or, similarly, calculation with hermitian Hamiltonian leads to increase the corresponding values. The model reproduces all the results on the particle oscillations, however it is oriented to the description of the above-mentioned channels. Also we touch on the problem of infrared singularities. The approach under study is infrared-free.
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Field and phenomenological description of absorption of particles
The complicated processes in the medium (decays, reactions and $n\bar{n}$ conversion) involving final state absorption are considered. The calculations in the framework of field and phenomenological approaches are compared. The reasons for disagreement are studied. The field approach can tend to increase of total process probability as well as probability of channel corresponding to absorption, in comparison with phenomenological model.
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Absorption in a Particle Oscillations
In the framework of field approach with finite time interval the particle oscillations in a medium are considered. The absorption in a final states do not lead to dramatic suppression of ab-transitions. Also we touch on the problem of infrared singularities. The approach under study is infrared-free. It is shown that "correction" published recently [A.Gal, Phys. Rev. C61 (2000) 028201] is clearly wrong.
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Reason for the large scale differences in the results for the neutron-antineutron oscillation problem
It is shown that there is a double counting in the standard model of $n\bar {n}$ mixing in the medium, resulting in full cancellation of leading terms. The direct calculation of $n\bar{n}$ transition followed by annihilation is performed. The lower limit for the free-space $n\bar{n}$ oscillation time is $τ_{n\bar{n}} \sim T_{n\bar{n}}>10^{16}y$, where $T_{n\bar{n}}$ is the lifetime of neutron bound in a nucleus. This limit exceeds the previous one by 16 orders of magnitude.
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Cause of Disparity between the Results for the $n\bar{n}$ Transition Problem
We show that there is a double counting in the standard model of $n\bar{n}$ mixing in the medium, resulting in full cancellation of leading terms. The direct calculation of $n\bar{n}$ transition, annihilation is performed. For lower limit on the free-space $n\bar{n}$ oscillation time we get $τ_{min} \sim 10^{31}y$.
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Reason of Large Scale Difference of the Results in the Neutron- antineutron Oscillation Problem
We expose a grave drawback hidden in the standard model of neutron-antineutron transitions in a medium. Correcting it, one improves a limit on the free-space neutron-antineutron oscillation time by 31 orders of magnitude.
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