Chromomagnetism,flavour symmetry breaking and S-wave tetraquarks

The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty. PACS 12.39.-x; 12.39.Mk; 12.40.Yx     

Microcavity polariton splitting of intersubband transitions

The optical response of the intersubband excitation of multiple two-dimensional electron gases within a semiconductor microcavity has been studied through angle-dependent reflectance measurements. Using a resonator based on total internal reflection, a clear splitting of about 14 meV of the coupled intersubband cavity modes is observed from 10 K to room temperature, with resulting polaritonlike dispersion. The experimental findings are in good agreement with theoretical calculations performed in a transfer-matrix formalism.     

Nonlinear quasiparticle tunneling between fractional quantum hall edges

Remarkable nonlinearities in the differential tunneling conductance between fractional quantum Hall edge states at a constriction are observed in the weak-backscattering regime. In the nu=1/3 state a peak develops as temperature is increased and its width is determined by the fractional charge. In the range 2/3相似文献   

A model of genetic code based on U_{q \to {\text{O}}} {\text{(}}sl(2) \oplus sl(2))^* {\text{)}}

The ratios of the codon usage in the quartets and sextets for 6 biological species belonging to the vertebrate series, with a statistics of codons larger than 200.000, exhibit a correlated behaviour, which fits naturally in the framework of the crystal basis model of the genetic code based on .     

A non-linear Rζ gauge condition for the electroweak SU(2) × U(1) model

A non-linear R_ζ gauge condition is presented and explicitly developed in the framework of the SU(2)×U(1) gauge model. We give the corresponding Feynman rules, which are simpler than in R_ζ gauges, because couplings involving unphysical Higgs and gauge bosons disappear or simplify. The Faddeev-Popov sector is more elegant, the ghosts coupling to neutral gauge bosons like in scalar electrodynamics. Finally, as a practical example, the transition Higgs→γγ is considered and compared with the usual calculation in linear gauges.     

About the non-relativistic structure of the conformal algebra

A new basis of the conformal algebra is proposed, which makes appear two conjugated Schrödinger algebras. This basis allows to exhibit a chain which does not contain the Poincaré algebra, between theI (4, 2) algebra and the (two-dimensional) extended Galilean one. This non-relativistic structure of the conformal algebra is well adapted to discuss some extreme models of hadrons based on collinear massless particles.     

Reactivity and selectivity of homolytic substitution reactions on the peroxyacid group

Peracids in solution may undergo homolytic decomposition leading mostly to mixtures of acid and alcohols, these Latters being formed from either the peracid or the solvent

The peracid behaves as source of radicals and also as substrate thus presenting two radicophile centers

- with a nucleophilic radical (R' from peracid or S' from solvent) the site of attack is the 0-0 bond of the peracid yielding an alcohol (NuOH). The rate of this reaction increases with increasing nucleophilicity of the radical ; this reactivity is interpreted in terms of frontier orbital perturbation theory, taking into account both the orbital energy level difference and the orbital overlap.- when the radical is electrophilic, it abstracts rather the hydrogen of the peroxidic group Leading to decomposition of the peracid into acid.Hydrogen abstraction from the solvent may be also observed in appropriate cases : this process can be used for free radical hydroxylation of hydrocarbons.The relative importance of these three chain reactions in competition : 0-0 bound attack, hydrogen abstraction from the peracid and solvent transfer reaction were studied as a function of structure of the radicals, solvent properties and temperature.     

Gluon exchange corections to the nucleon magnetic moment in the mit bag model

We have calculated gluon exchange corrections to the nucleon magnetic moment predictions of the MIT bag model. The sizeable coupling constant $\text{g}{}^2{}_{\mathrm{c}}\text{/}\text{4π=0.5}$ does not produce an enormous correction (≈10%), but it is in the wrong direction to ameliorate the present 30% disagreement with experiment.     

Narrow multiquark baryons

We assume that two recently discovered narrow hypercharge zero states are composed of four quarks and an antiquark. Expected masses and decay modes of other multiquark baryons are predicted.     

Quantum Transport in Presence of Bound States – Noise Power

The impact of bound states in Landauer‐Büttiker scattering approach to non‐equilibrium quantum transport is investigated. We show that the noise power at frequency ν is sensitive to all bound states with energies ω_b satisfying . We derive the exact expression of the bound state contribution and compare it to the one produced by the scattering states alone. The theoretical and experimental consequences of this result are discussed.