Recent b→sℓℓ anomalies may imply the existence of a new Z′ boson with left-handed Z′bs and Z′μμ couplings. Such a Z′ may be directly observed at LHC via bs¯→Z′→μ+μ−, and its relevance to b→sℓℓ may be ...studied by searching for the process gs→Z′b→μ+μ−b. In this paper, we analyze the capability of the 14 TeV LHC to observe the Z′ in the μ+μ− and μ+μ−b modes based on an effective model with major phenomenological constraints imposed. We find that both modes can be discovered with 3000 fb−1 data if the Z′bs coupling saturates the latest Bs−B¯s mixing limit from UTfit at around 2σ. Besides, a tiny right-handed Z′bs coupling, if it exists, opens up the possibility of a relatively large left-handed counterpart, due to cancellation in the Bs−B¯s mixing amplitude. In this case, we show that even a data sample of O(100) fb−1 would enable discovery of both modes. We further study the impact of a Z′bb coupling as large as the Z′bs coupling. This scenario enables discovery of the Z′ in both modes with milder effects on the Bs−B¯s mixing, but obscures the relevance of the Z′ to b→sℓℓ. Discrimination between the Z′bs and Z′bb couplings may come from the production cross section for the Z′bb¯ final state. However, we do not find the prospect for this to be promising.
We propose a method to probe the coupling of the Higgs to strange quarks by tagging strange jets at future lepton colliders. For this purpose we describe a jet-flavor observable, JF, that is ...correlated with the flavor of the quark associated with the hard part of the jet. Using this variable, we set up a strangeness tagger aimed at studying the decay h → ss. We determine the sensitivity of our method to the strange Yukawa coupling, and find it to be of the order of the standard-model expectation.
Maximal speed of quantum propagation Arbunich, J.; Pusateri, F.; Sigal, I. M. ...
Letters in mathematical physics,
06/2021, Letnik:
111, Številka:
3
Journal Article
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For Schrödinger equations with both time-independent and time-dependent Kato potentials, we give a simple proof of the maximal speed bound. The latter states that the probability to find the quantum ...system outside a ball of radius proportional to the time lapsed decays as an inverse power of time. We give an explicit expression for the constant of proportionality in terms of the maximal energy available to the initial condition. For the time-independent part of the interaction, we require neither decay at infinity nor smoothness.
Using potential perturbation techniques, we investigated the kinetics of electroadsorption processes of ions with different dimensions and different concentrations into activated carbon electrodes ...with various porous structures. We found that the ratio between the pore size and the ion size is of great significance in terms of electroadsorption kinetics. Microporous carbon fiber electrodes exhibited a lower charging rate as compared with mesoporous aerogel carbon. The use of activated aerogel electrodes with a fractal structure composed of both micro- and mesopores, was found to be the best for effective electroadsorption due to both high electrical double layer capacity obtained and high rates of electroadsorption. We also explored the kinetics of electroadsorption processes into molecular sieve carbon electrodes, demonstrating that, despite the hindered adsorption processes into these electrodes, it is possible to obtain effective deionization by using them for selective water desalination processes.
Measurements were done on a relatively wide pore carbon molecular sieve membrane (CMSM) by means of a range of probe molecules (He, H
2, N
2, CH
4, CO
2, C
5H
12) between 25 and 500
°C. At high ...temperatures, where adsorption effects are attenuated, the permeance of the carbon membrane to pure gases displayed the molecular weight and temperature dependence expected from Knudsen diffusion, even though the pore size distribution lies demonstrably below 0.55
nm. Utilizing a concept of an effective diameter, the authors analyzed the temperature dependence of the probe molecules’ permeabilities and separated out the relative contribution of the different gas transport mechanisms in the pores of the carbon microporous membranes. Calculations of the total gas permeance from two different idealized membrane pore structures were made and compared to measured permeances. The comparison showed that an idealized pore structure comprising larger and smaller diameter pore regions essentially connected in series can reasonably explain the measurements. The estimate for the larger pore diameter was found by using the temperature dependence of
n-pentane permeance, which showed behavior approaching that to be expected for activated diffusion typical of sieving membranes. The larger diameter region of the pore system was estimated to be 0.58
nm and the smaller diameter region to be 0.43–0.48
nm. After correction for the contribution of Knudsen diffusion, the gases tested could be ranked according to the contribution of adsorption-mediated transport as follows: CO
2>CH
4>N
2>H
2>He based on the calculated net energies for pore transport. This is consistent with the ranking to be found for adsorption isotherms of these gases on activated glassy carbon.
We report herein on a study of the electrical double layer capacitance of microporous activated carbon fibers electrodes as a function of the concentration of the electrolyte in aqueous solutions. ...The accessibility of the subnanopores in the electrode-to-ion adsorption decreases as the ionic strength of the solutions decreases, due to the increase in the hydration shell of the ions. Evaluating the concentration effect on the effective size of the ions was possible by the use of highly selective carbon molecular sieve electrodes, produced by the chemical vapor deposition (CVD) of carbon on the ACF surface, which partially closes the entries to the pores. The CVD process was carried out by the pyrolysis of benzene. This study provides a basis for the rigorous evaluation of the size of solvated ions in solutions at different levels of solvation.
The reaction of three types of carbon with oxygen (1
atm) at different temperatures was investigated. The precursors for the carbons studied were Kapton (polyimide), cellulose and cellulose that was ...carbonized with ammonium chloride. Two consecutive processes are confirmed to occur during the reaction with oxygen. The build up of oxygenated surface complexes by chemisorption of oxygen and the well-known gasification of these surface groups. The carbons originating from Kapton or cellulose carbonized in the presence of NH
4Cl contain nitrogen. As the nitrogen content in the carbon is higher, the uptake of oxygen at the carbon surface by chemisorption is more pronounced. Hall effect measurements demonstrate that electrons are the major charge carrier in nitrogen containing carbons, while holes are the charge carriers in the nitrogen-free carbons. The determination of the type of charge carrier explains the observation that the nitrogen-containing carbons chemisorb oxygen more readily than the nitrogen-free carbons. Electronic conductivity demonstrates the affect of the sign of the charge carrier on the chemisorption of the carbons during chemisorption of oxygen. While in the case of n-type carbon a decrease in the conductivity was observed, p-type carbons exhibit a slight increase followed by a decrease in the conductivity.
Dispersive analysis of charge transfer models Rodnianski, I.; Schlag, W.; Soffer, A.
Communications on pure and applied mathematics,
February 2005, Letnik:
58, Številka:
2
Journal Article
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