Topic
Strangeness
About: Strangeness is a research topic. Over the lifetime, 3876 publications have been published within this topic receiving 71559 citations. The topic is also known as: strange.
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TL;DR: In this paper, the weak and electromagnetic interactions of leptons are examined under the hypothesis that the weak interactions are mediated by vector bosons, and it is shown that the simplest partially-symmetric model reproducing the observed electromagnetic and weak interactions requires the existence of at least four vector-boson fields (including the photon).
4,387 citations
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TL;DR: In this article, the authors assume that the strong interactions of baryons and mesons are correctly described in terms of the broken "eightfold way", and they are tempted to look for some fundamental explanation of the situation.
2,244 citations
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TL;DR: In this paper, the authors explore the consequences of the assumption that the direct and induced weak neutral currents in an SU(2) gauge theory conserve all quark flavors naturally, i.e., for all values of the parameters of the theory.
Abstract: We explore the consequences of the assumption that the direct and induced weak neutral currents in an $\mathrm{SU}(2)\ensuremath{\bigotimes}\mathrm{U}(1)$ gauge theory conserve all quark flavors naturally, i.e., for all values of the parameters of the theory. This requires that all quarks of a given charge and helicity must have the same values of weak ${T}_{3}$ and ${\stackrel{\ensuremath{\rightarrow}}{T}}^{2}$. If all quarks have charge +2/3 or -1/3 the only acceptable theories are the "standard" and "pure vector" models, or their generalizations to six or more quarks. In addition, there are severe constraints on the couplings of Higgs bosons, which apparently cannot be satisfied in pure vector models. We also consider the possibility that neutral currents conserve strangeness but not charm. A natural seven-quark model of this sort is described. The experimental consequences of charm nonconservation in direct or induced neutral currents are found to be quite dramatic.
1,203 citations
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TL;DR: In this article, the chiral logarithmic corrections to the axial current for semileptonic hyperon decay and for the analysis of the strangeness content of the proton are computed as examples.
811 citations
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TL;DR: In this article, the authors measured the charged-particle spectra at the BNL Relativistic Heavy Ion Collider (RHIC) time projection chamber and reported the average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates as a function of collision system and centrality.
Abstract: Identified charged-particle spectra of pi(+/-), K(+/-), p, and (p) over bar at midrapidity (vertical bar y vertical bar < 0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d + Au collisions at root s(NN) = 200 GeV and for Au + Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm(3) for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au + Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au + Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close to the predicted phase-transition temperature, suggesting that chemical freeze-out happens in the vicinity of hadronization and the chemical freeze-out temperature is universal despite the vastly different initial conditions in the collision systems. The extracted kinetic freeze-out temperature, while similar to the chemical freeze-out temperature in pp, d + Au, and peripheral Au + Au collisions, drops significantly with centrality in Au + Au collisions, whereas the extracted transverse radial flow velocity increases rapidly with centrality. There appears to be a prolonged period of particle elastic scatterings from chemical to kinetic freeze-out in central Au + Au collisions. The bulk properties extracted at chemical and kinetic freeze-out are observed to evolve smoothly over the measured energy range, collision systems, and collision centralities.
784 citations