121620440
Study of Approximations in the Nuclear Pairing-Force Problem
122236095
APPROACH TO THE NUCLEAR MANY-BODY PROBLEM BY A VARIATIONALLY DETERMINED TRANSFORMATION.
123621331
APPROACH TO THE NUCLEAR MANY-BODY PROBLEM BY VARIATIONALLY DETERMINED TRANSFORMATION. II.
We present a generalization of the Hartree-Fock (HF) method incorporating two-body correlations. The correlations are introduced by means of a unitary operator ${e}^{\mathrm{iF}}$, where $F$ is a Hermitian one- and two-body operator to be determined by the variational principle. Assuming that the matrix elements of $F$ are small so that powers of $F$ higher than the second may be neglected, a set of linear equations determining $F$ is obtained. The relation between our method and methods used to treat singular interactions is discussed. The method is applied to two recently suggested models and is compared with the HF method, second-order perturbation theory, and with the random-phase approximation. It is found that our method yields very good results within the range of validity of our approximations, which seems to call forth applications to more realistic problems. Possible applications to the study of collective phenomena in nuclei are indicated.
118409646
Superfluidity of hadronic matter
SummaryThe mesons in the nucleon are associated with a Bose system with an energy excitation spectrum ε(p), wherep is the corresponding momentum. This spectrum can be investigated by studying the nucleon recoil in one-meson production processes. It turns out that
$$\mathop {\lim }\limits_{p \to 0} (\varepsilon /p) \ne 0$$
. This is the Landau criterion for superfluidity. Herefrom we infer that hadronic matter is superfluid. Possible manifestations of this phenomenon in strong interactions are a bootstrap relation between the masses of mesonic and baryonic resonances, the shift of the δ-resonance in nuclei, the existence of a maximum resonance mass equivalent to an ionization point and the existence of a critical temperature of hadronic matter instead of a maximum temperature.RiassuntoI mesoni nel nucleone sono associati per mezzo di un sistema di bose con uno spettro di energie di eccitazione ε(p), dovep è l'impulso corrispondente. Si può analizzare questo spettro studiando il rinculo del nucleone nei processi di produzione di un mesone. Risulta che
$$\mathop {\lim }\limits_{p \to 0} (\varepsilon /p) \ne 0$$
. Questo è il criterio di landau per la superfluidità. Da ciò si inferisce che la materia adronica è superfluida. Possibili manifestazioni di questo fenomeno nelle interazioni forti sono una relazione di bootstrap fra le masse delle risonanze mesoniche e barioniche, lo spostamento della risonanza δ nei nuclei, l'esistenza di una massa massima della risonanza equivalente ad un punto di ionizzazione e l'esistenza di una temperatura critica della materia adronica invece di una temperatura massima.РезюмеМезоны в нуклоне связываутся с Гозе-системой с энергетическим спектром возбуждения ε(p), гдеp есть соответствующии импульс. Этот спектр может быть исследован посредством изучения отдачи нуклона в процессе рождения одного пиона. Оказывается, что
$$\mathop {\lim }\limits_{p \to 0} (\varepsilon /p) \ne 0$$
. Это представляет критерий Ландау для сверхтекучести, из которого мы делаем вывод, что адронное вещество является сверхтекучим. Возможные проявления этого явления в сильных взаимодействиях представляют: соотношения бутстрепа между массами мезонных и барионных резонансов, сдвиг δ резонанса в ядрах, существование резонансной массы, эквивалентной точке ионизации, и существование критической температуры адронного вещества вместо максимальной темпатуры.
122704344
Mesonic structure in the nucleon
123581677
LINEARIZED VERSION OF THE HARTREE--FOCK METHOD.
122119912
Kirchhoff's theorem and the Casimir effect
Kirchhoff's thermodynamically based classical theorem (the energy density of the radiation in equilibrium is a function of T only) is used to obtain a relation relevant to study of the Casimir effect. We use it to obtain the zero-temperature Casimir energy without recourse to regularizaion. The intimate connection between the zero-point energy and the thermal Bose occupancy expression noted by Einstein and Stern at the turn of the century is invoked to account for the results.
120150178
Measurement of anomalous muon pair production in electron-positron annihilations
We have observed 16 events of the type ..mu../sup +/..mu../sup -/ + (missing energy and momentum) from e/sup +/e/sup -/ annihilations at center-of-mass energies between 6.4 and 7.4 GeV. Taking into account QED backgrounds, we find an excess of 11 anomalous dimuon events. If these are attributed to the production and subsequent decay of a pair of heavy leptons L/sup + -/, we obtain the muonic braching ratio B ((L/sup +/ ..-->.. ..mu../sup +/..nu../sub ..mu../nu-bar/sub L/)/ (L/sup +/ ..-->.. all)) = 0.22/sup +0.07//sub -0.08/.
53454093
Phase-space formulation of quantum mechanics and quantum-state reconstruction for physical systems with Lie-group symmetries
We present a detailed discussion of a general theory of phase-space distributions, introduced recently by the authors @J. Phys. A 31 ,L 9 ~1998!#. This theory provides a unified phase-space formulation of quantum mechanics for physical systems possessing Lie-group symmetries. The concept of generalized coherent states and the method of harmonic analysis are used to construct explicitly a family of phase-space functions which are postulated to satisfy the Stratonovich-Weyl correspondence with a generalized tracing condition. The symbol calculus for the phase-space functions is given by means of the generalized twisted product. The phase-space formalism is used to study the problem of the reconstruction of quantum states. In particular, we consider the reconstruction method based on measurements of displaced projectors, which comprises a number of recently proposed quantum-optical schemes and is also related to the standard methods of signal processing. A general group-theoretic description of this method is developed using the technique of harmonic expansions on the phase space. @S1050-2947~99!00702-7#
120319912
A large-area magnetic spectrometer for the study of high-energy neutrino interactions
Abstract We describe the design, construction, and performance of a large solid iron magnetic spectrometer which has been used to i dentify and measure the momentum of muons produced by interactions of neutrinos with nucleons. The rms momentum resolution varies from 10 to 15 percent between 5 and 150 GeV/ c .
122141713
A liquid-scintillator total-absorption hadron calorimeter for the study of neutrino interactions
Abstract We describe the performance of a large-volume liquid-scintillator calorimeter which has been used to measure the total energy of hadrons produced by interactions of neutrinos with nucleons. The resolution of the calorimeter is about 12% rms for incident pions over the energy range 20–150 GeV, and about 15% for neutrino-induced hadron systems in the chosen fiducial volume after corrections for imperfect energy containment.