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91.
The inelastic response of a Borromean trimer composed of three identical bosons is explored. To this end we use the quadrupole approximation as the excitation mechanism of the bosonic system from its ground state. We utilize the hyperspherical-harmonics expansion to solve the Schroedinger equation and the Lorentz integral transform method to calculate the reaction. It is found that the magnitude of the response function and corresponding sum rules increase as a power law when approaching the three-body threshold. It is also found that this increase is governed by unnatural exponents. 相似文献
92.
We study algebraic properties of the Wiener algebra of absolutely convergent power series on the closed unit disc. In particular, we prove a form of Weierstrass preparation for algebraic functions in this algebra. 相似文献
93.
The inelastic response of a bosonic trimer is explored in the confines of the Borromean region. To this end we model the interaction between the external field and the bosonic system as a photoabsorptionlike process and study the response of the trimer in the quadrupole approximation. We utilize the hyperspherical-harmonics expansion to solve the Schr?dinger equation and the Lorentz integral transform method to calculate the reaction. It is found that the magnitude of the response function and corresponding sum rules increase exponentially when approaching the 3-body threshold. It is also found that this increase is governed by unnatural exponents. The connection between our results and radio-frequency experiments in ultracold atom systems is made. 相似文献
94.
The 4He total photoabsorption cross section is calculated with the realistic nucleon-nucleon potential Argonne V18 and the three-nucleon force (3NF) Urbana IX. Final state interaction is included rigorously via the Lorentz integral transform method. A rather pronounced giant resonance with peak cross sections of 3.0 (3.2) mb is obtained with (without) the 3NF. Above 50 MeV strong 3NF effects, up to 35%, are present. Good agreement with experiment is found close to threshold. A comparison in the giant resonance region is inconclusive, since data do not show a unique picture. 相似文献
95.
Optical sectioning is performed by collecting the fluorescent emission of two-exciton states in colloidal quantum dots. The two-exciton state is created by two consecutive resonant absorption events, thus requiring unprecedented low excitation energy and peak powers as low as 10(5) W/cm(2). The depth resolution is shown to be equivalent to that of standard multiphoton microscopy, and it was found to deteriorate only slowly as saturation of the two-exciton state is approached, owing to signal contribution from higher excitonic states. 相似文献
96.
97.
The photoassociation of Efimov trimer, composed of three identical bosons, is studied using the long wavelength approximation. It is shown that for identical particles the leading contribution comes from the r 2 s-mode operator and from the quadrupole d-mode operator. Log-periodic oscillations are found in the photoassociation response function, both near the energy threshold for the leading s-wave reaction, and in the high frequency tail for all partial waves. 相似文献
98.
Srubabati Goswami Raghavan Rangarajan K. Agashe A. Bandyopadhyay K. Bhattacharya B. Brahmachari C. Burgess E. J. Chun D. Choudhury P. K. Das A. Dighe R. Godbole S. Goswami N. Gupta M. Kaplinghat D. Indumathi J. Forshaw Y. Y. Keum B. Layek D. Majumdar N. Mahajan P. Mehta R. N. Mohapatra N. Mondai S. More Y. Nir S. Pakvasa M. K. Parida M. Ravikumar G. Rajasekaran P. Ramadevi R. Rangarajan S. D. Rindani D. P. Roy P. Roy N. Sahu A. Samanta Y. Shadmi A. M. Srivastava S. Uma Sankar R. Vaidya U. Yajnik 《Pramana》2004,63(6):1391-1405
This is the report of neutrino and astroparticle physics working group at WHEPP-8. We present the discussions carried out
during the workshop on selected topics in the above fields and also indicate progress made subsequently. The neutrino physics
subgroup studied the possibilities of constraining neutrino masses, mixing and CPT violation in lepton sector from future
experiments. Neutrino mass models in the context of Abelian horizontal symmetries, warped extra dimensions and in the presence
of triplet Higgs were studied. Effect of threshold corrections on radiative magnification of mixing angles was investigated.
The astroparticle physics subgroup focused on how various particle physics inputs affect the CMBR fluctuation spectrum, and
on brane cosmology. This report also contains an introduction on how to use the publicly available code CMBFAST to calculate
the CMBR fluctuations. 相似文献
99.
The smallness of the quark sector parameters and the hierarchy between them could be the result of a horizontal symmetry broken by a small parameter. Such an explicitly broken symmetry can arise from an exact symmetry which is spontaneously broken. Constraints on the scales of new physics arise from new flavor-changing interactions and from Landau poles, but do not exclude the possibility of observable signatures at the TeV scale. Such a horizontal symmetry could also lead to many interesting results: (i) quark—squark alignment that would suppress, without squark degeneracy, flavor-changing neutral currents induced by supersymmetric particles, (ii) exact relations between mass ratios and mixing angles, (iii) a solution of the μ-problem and (iv) a natural mechanism for obtaining hierarchy among various symmetry-breaking scales. 相似文献
100.
The divalent organic cation, methyl green (MG), undergoes a slow transformation (6 h) to a monovalent cation, carbinol (MGOH(+)) upon dilution of its solution (10 mM), or in a buffer at neutral pH. Adsorption isotherms of MG on montmorillonite were determined by two procedures, both of which yield a final pH of suspensions between 7 to 7.4. When the amounts of MG in suspension were lower than the cation-exchange capacity (CEC) of the clay (0.8 mol(c)/kg clay), no measurable amount of MG remained in solution. The maximal amounts of MGOH(+) adsorbed were larger than those of MG(2+), being 1.15 and 0.75 mol MG/kg clay, respectively, corresponding to 140% of the CEC in the first case. On a charge basis the adsorption of added MG(2+) amounts to 185% of the CEC, which raises the possibility that a certain fraction of MG(2+) transformed into the monovalent form during the incubation period, since other divalent organic cations previously studied only adsorbed up to the CEC (paraquat), or slightly above it (diquat). Adsorption of MG on sepiolite (CEC=0.15 mol(c)/kg) further emphasizes the two patterns of its adsorption. The maximal adsorbed amounts of MG(2+) and MGOH(+) were 0.09 and 0.30 mol/kg clay, respectively. X-ray diffraction measurements gave lower values for the basal spacings for montmorillonite-MG(+) than for MGOH(+), suggesting that MG(2+) binds two clay platelets together, as in the case of other divalent cations. A competition for adsorption between MG and the monovalent organic cation, acriflavin (AF), gave lower adsorbed amounts of AF when competing with MG(+), which is interpreted to be due to the smaller basal spacing in this case, which partially inhibits the entry of AF molecules into the interlammelar space. Spectra of montmorillonite-MG particles in the visible range exhibited significant differences between clay-MG and clay-carbinol. Copyright 2000 Academic Press. 相似文献