119813214
The Search for New Families of Elementary Particles
A new particle was observed at Fermilab having a mass and lifetime that place it in a region of the elementary-particle spectrum that remains almost unexplored. Its significance is that it reveals an entirely new family, the existence of which implies that there is some hitherto unobserved property matter that distinguishes the particles in the new family from all the more familiar ones. Particle properties are reviewed in order to explain the observation of the new particle. It is suggested that a new hadron is the most likely interpretation.
123899161
NEUTRINOS AND MUONS IN AREA 1.
118712243
Comments on the letter «Limits on the electromagnetic production of heavy leptons»
121246612
Scaling-variable distributions in high-energy inelastic neutrino interactions
38997255
Prototype detector for ultrahigh energy neutrino detection
Abstract Necessary technical experience is being gained from successful construction and deployment of current prototype detectors to search for UHE neutrinos in Antarctica, Lake Baikal in Russia, and the Mediterranean. The prototype detectors have also the important central purpose of determining whether or not UHE neutrinos do in fact exist in nature by observation of at least a few UHE neutrino-induced leptons with properties that are not consistent with expected backgrounds. We discuss here the criteria for a prototype detector to accomplish that purpose in a convincing way even if the UHE neutrino flux is substantially lower than predicted at present.
118973535
Some Recent Advances in Neutrino Physics
One answer to questions concerning the subject matter of elementary particle physics and its position within the physical sciences is that particle physics is the study of creation. To justify this idea, at least in part, consider the “big bang” model of creation of the universe. In that model the primeval fireball involved very high temperatures, estimated to be greater than 1011 degrees Kelvin (°K), which is to be compared with the interior temperature of the sun at about 107 degrees Kelvin. We believe the sun to be a nuclear furnace, generating its energy by individual nuclear interactions in the million electron volt (MeV) energy range. In the “big bang” the energies involved in the individual particle interactions would have been more than 104 times larger than in the sun, and thus in the tens of giga-electron volts (GeV). This is precisely the energy region of present-day high energy or elementary particle physics laboratory experiments. In this sense, then, laboratory experiments that study, even indirectly, lepton-lepton scattering or quark-quark interactions are revisiting creation.
15829252
Factorization of analytic representations in the unit disc and number-phase statistics of a quantum harmonic oscillator
The inner - outer part factorization of analytic representations in the unit disc is used for an effective characterization of the number-phase statistical properties of a quantum harmonic oscillator. It is shown that the factorization is intimately connected with the number-phase Weyl semigroup and its properties. In the Barut - Girardello analytic representation the factorization is implemented as a convolution. Several examples are given which demonstrate the physical significance of the factorization and its role for quantum statistics. In particular, we study the effect of phase-space interference on the factorization properties of a superposition state.
119480279
Generalized coherent states are unique Bell states of quantum systems with Lie-group symmetries
Entanglement is the main quantum mechanical feature that distinguishes between quantum and classical physics. A state of a quantum system, consisting of two subsystems, is called entangled if it cannot be represented as a direct product of states of the subsystems. The nonclassicality of such a situation is expressed mathematically by the violation of Bell’s inequality @1,2#. More specifically, let us consider a quantum system A ~e.g., a mode of the quantized radiation field or a spin-j particle!, which is split or decays into two subsystems B and C @3#. A pure quantum state that upon splitting will not violate Bell’s inequality ~i.e., a quantum state that possesses the basic attribute of classical physics ! has been called the Bell state @4#. It has been proven @4‐6# that a state that factorizes upon splitting into a direct product cannot violate Bell’s inequality, while a state that gives rise to an entangled ~i.e., nonproduct! state can always, by a suitable choice of local apparatus, be made to violate the inequality. Therefore the Bell state of the system A must factorize upon splitting into the direct product of states of the subsystems.
119389242
Derivation of the critical temperature for the superfluid phase of hadronic matter
Abstract We give a quantitative derivation of the temperature at which superfluidity of hadronic matter ends. Using considerations similar to those used by Landau for 4 He, we find T c ⩽ 190 MeV in close agreement with Hagedorn's “limiting” temperature.
13881394
Classical properties of generalized coherent states: from phase-space dynamics to Bell's inequality
We review classical properties of harmonic-oscillator coherent states. Then we discuss which of these classical properties are preserved under the group-theoretic generalization of coherent states. We prove that the generalized coherent states of quantum systems with Lie-group symmetries are the unique Bell states, i.e., the pure quantum states preserving the fundamental classical property of satisfying Bell's inequality upon splitting.
118910552
Collective effects in the collapse-revival phenomenon and squeezing in the Dicke model
Resonant interaction of a collection of two-level atoms with a single-mode coherent cavity field is considered in the framework of the Dicke model. We focus on the role of collective atomic effects in the phenomenon of collapses and revivals of the Rabi oscillations. It is shown that the behavior of the system strongly depends on the initial atomic state. In the case of the initial half-excited Dicke state we account for a number of interesting phenomena. The correlations between the atoms result in a suppression of the revival amplitude, and the revival time is halved, compared to the uncorrelated fully excited and ground states. The phenomenon of squeezing of the radiation field in the atom-field interaction is also discussed. For the initial fully excited and ground atomic states, the field is squeezed on the short-time scale, and squeezing can be enhanced by increasing the number of atoms. Some empirical formulas are found which describe the behavior of the system in excellent agreement with numerical results. For the half-excited Dicke state, the field can be strongly squeezed on the long-time scale in the case of two atoms. This kind of squeezing is enhanced by increasing the intensity of the initial coherent field and is of the same nature as revival-time squeezing in the Jaynes-Cummings model. The appearance of this long-time squeezing can be explained using the factorization approximation for semiclassical atomic states. @S1050-2947~98!07309-0#