Single Top Quark at Future Hadron Colliders. Complete Signal and Background Study

We perform a detail theoretical study including decays and jet fragmentation of all the important modes of the single top quark production and all basic background processes at the upgraded Tevatron and LHC colliders. Special attention was paid to the complete tree level calculation of the QCD fake background which was not considered in the previous studies. Analysis of the various kinematical distributions for the signal and backgrounds allowed to work out a set of cuts for an efficient background suppression and extraction of the signal. It was shown that the signal to background ratio after optimized cuts could reach about 0.4 at the Tevatron and 1 at the LHC. The remaining after cuts rate of the signal at the LHC for the $lepton+jets$ signature is expected to be about 6.1 pb and will be enough to study the single top physics even during the LHC operation at a low luminosity.Comment: 15 pages, LaTex, 7 figure

Tuning the Molecular and Cationic Affinity in a Series of Multifunctional Metal-Organic Frameworks Based on Dodecanuclear Zn(II) Carboxylate Wheels

A series of new zinc(II)-thiophene-2,5-dicarboxylate (tdc) MOFs based on novel dodecanuclear wheel-shaped building blocks has been synthesized in almost quantative yields. Single-crystal X-ray diffraction analyses reveal 3D porous frameworks with a complex composition [Zn12(tdc)6(glycolate)6(dabco)3] where glycolate is a deprotonated polyatomic alcohol (ethylene glycol, EgO2, 1; 1,2-propanediol, PrO2, 2; 1,2-butanediol, BuO2, 3; 1,2-pentanediol, PeO2, 4; glycerol, GlO2, 5) and dabco is 1,4-diazo[2.2.2.]bicyclooctane. All compounds 1-5 are isostructural except for pendant groups of the diols decorating the surface of channels. The adsorption of small gases (N2, CO2, CH4, C2H2, C2H4, C2H6) and larger hydrocarbons (benzene, cyclohexane) both in liquid and vapor phases was thoroughly investigated for all compounds. The zero-coverage adsorption enthalpies, Henry constants, and selectivity factors by various models are calculated and discussed. The versatile adsorption functionality of the title series results from the variable nature of the diol and could be tailored for a specific adsorbate system. For example, 1 shows excellent selectivity of benzene over cyclohexane (20:1 for vapors, 92:1 for liquid phase), while 4 demonstrates unprecedented adsorption preference of cyclohexane over benzene (selectivity up to 5:1). The compound 5 demonstrates great adsorption selectivity for CO2/N2 (up to 75.1), CO2/CH4 (up to 7.7), C2H2/CH4 (up to 14.2), and C2H4/CH4 (up to 9.4). Also, due to polar nature of the pores, 5 features size-selective sorption of alkaline metal cations in order Li+ > Na+ > K+ > Cs+ as well as a notable luminescent response for cesium(I) ions and urea. © 2019 American Chemical Society

Study of the processes

We report preliminary results on the measurement of the cross sections of the processes e+e− → K+K−π+π− and e+e− → ϕη in the c.m.energy range from 1.5 GeV to 2 GeV with the CMD-3 detector. The cross sections of these processes agree with BaBar results and have better accuracy

Study of the process e+e−→π+π−π+π− in the c.m. energy range 920–1060 MeV with the CMD-3 detector

A cross section of the process e+e−→π+π−π+π− has been measured using 6798±93 signal events from a data sample corresponding to an integrated luminosity of 9.8 pb−1 collected with the CMD-3 detector in the center-of-mass energy range 920–1060 MeV. The measured cross section exhibits a pattern of interference of the ϕ(1020)→π+π−π+π− decay with a non-resonant process e+e−→π+π−π+π−, from which we obtain the branching fraction of the doubly suppressed decays (by G-parity and OZI rule): B(ϕ→π+π−π+π−)=(6.5±2.7±1.6)×10−6