Search results for "s-wave"
showing 10 items of 26 documents
Hierarchies of length-scale based typology in anisotropic U(1)s -wave multiband superconductors
2019
Since Ginzburg and Landau's seminal work in 1950, superconducting states have been classified by the hierarchy of the fundamental length scales of the theory, the magnetic-field penetration lengths ...
P- versus S-wave at rest in LH2
1992
Abstract The annihilation p p →π 0 π 0 was measured for antiprotons stopped in liquid hydrogen (LH2). This reaction is only allowed from odd angular momentum states of the p p - atom . The resulting branching ratio BR ( p p →π 0 π 0 ) LH 2 =(6.93±0.22 stat ±0.37 syst )×10 −4 , combined with a previous measurement of the branching ratio BR ( p p →π + π − ) 2 P in gas from the 2P-state of p p suggests a fraction of P-wave annihilation in LH2 of (28.8±3.5)%, much larger than the values obtained from other annihilation channels. A method of reconciling the contradictory results is discussed.
Pion cloud contribution to the s-wave repulsion in pionic atoms
1995
Abstract The nuclear pion cloud contribution to the pion self-energy for pionic atoms is evaluated and one finds large cancellations between terms involving the ππ amplitude and other terms originating from the chiral lagrangian partners. While the individual terms depend strongly on the off-shell extrapolation of the ππ amplitude, the sum is model independent within the Olson and Turner family of chiral lagrangians keeping ξ + 4 η constant, as previously found for the πN → ππN and pion double-charge exchange in nuclei, and vanishes in the limit of m π → 0. One finds a small net repulsion which is however too small to account for the “missing” s-wave repulsion. A revision of the present sta…
Short range correlations in the pion s-wave self-energy of pionic atoms
1995
We evaluate the contribution of second order terms to the pion-nucleus s-wave optical potential of pionic atoms generated by short range nuclear correlation. The corrections are sizeable because they involve the isoscalar s-wave $\pi N$ amplitude for half off-shell situations where the amplitude is considerably larger than the on-shell one. In addition, the s-wave optical potential is reanalyzed by looking at all the different conventional contributions together lowest order, Pauli corrected rescattering term, second order absorptive effects, terms from the interaction of pions with the virtual pion cloud (chiral corrections) and correlation effects. Different off-shell extrapolations for t…
Threshold electro production of neutral pions at low q2 off the proton and off the deuteron
2000
Abstract The A1 Collaboration performs an extend program to measure threshold production of the neutral pion as test of Heavy Baryon Chiral Perturbation Theory. Starting with direct threshold measurements to extract the s wave amplitudes at threshold we continued with out of plane measurements with polarized beam to access the small p wave amplitudes. Coherent production off the deuteron is the first attempt to access the neutron amplitude in electro production.
Excitation power dependence of the Purcell effect in photonic crystal microcavity lasers with quantum wires
2013
The Purcell effect dependence on the excitation power is studied in photonic crystal microcavity lasers embedding InAs/InP quantum wires. In the case of non-lasing modes, the Purcell effect has low dependence on the optical pumping, attributable to an exciton dynamics combining free and localized excitons. In the case of lasing modes, the influence of the stimulated emission makes ambiguous the determination of the Purcell factor. We have found that this ambiguity can be avoided by measuring the dependence of the decay time on the excitation power. These results provide insights in the determination of the Purcell factor in microcavity lasers. © 2013 AIP Publishing LLC.
High-overtone bulk acoustic resonator as passive ground penetrating RADAR cooperative targets
2013
International audience; RAdio-frequency Detection And Ranging instruments—RADARs—are widely used for applications aimed at measuring passive target velocity or ranging for various metrology applications such as ground position and localization. Within the context of using piezoelectric acoustic passive sensors as cooperative targets to RADARs probed through a radiofrequency link, this paper reports on investigating the compatibility of narrowband resonator architectures with the classical operation mode of wideband RADAR instruments. Since single mode resonators are hardly compatible due to the limited bandwidth of their spectrum, the investigation has been extended to High-overtone Bulk Ac…
Determination of s - and p -wave I = 1/2 Kπ scattering amplitudes in N f = 2 + 1 lattice QCD
2018
Nuclear physics 932, 29 - 51 (2018). doi:10.1016/j.nuclphysb.2018.05.008
Meson-baryon threshold effects in the light-quark baryon spectrum
2008
We argue that selected $S$ wave meson-baryon channels may play a key role to match poor baryon mass predictions from quark models with data. The identification of these channels with effective inelastic channels in data analysis allows to derive a prescription which could improve the extraction and identification of baryon resonances.
Charmonium dissociation and heavy quark transport in hot quenched lattice QCD
2012
We study the properties of charmonium states at finite temperature in quenched lattice QCD on large and fine isotropic lattices. We perform a detailed analysis of charmonium correlation and spectral functions both below and above Tc. Our analysis suggests that the S wave states disappear at about 1.5 Tc. The charm diffusion coefficient is estimated and found to be approximately 1/{\pi}T at 1.5Tc {\leq} T {\leq} 3Tc.