ϒ( nS )→ B c ρ , B c K ⁎ decays with perturbative QCD approach

Abstract

Besides the traditional strong and electromagnetic decay modes, Υ(nS) meson can also decay through the weak interactions within the standard model of elementary particle. With anticipation of copious Υ(nS) data samples at the running LHC and coming SuperKEKB experiments, the twobody nonleptonic bottom-changing Υ(nS) → B * c π, B * c K decays (n = 1, 2, 3) are investigated with perturbative QCD approach firstly. The absolute branching ratios for Υ(nS) → B * c π and B * c K decays are estimated to reach up to about 10 −10 and 10 −11 , respectively, which might possibly be measured by the future experiments.b The investigation on the radiative decay of B * c meson can be found in, for example, Ref.[6] with QCD sum rules.

Study of the B¯q*→DM decays with perturbative QCD approach

“…Hence, the decay amplitudes for the nonfactorizable topologies have quite complicated structures, and the amplitude convolution integral involve the wave Among the three possible types of Feynman diagrams ( Fig.1, Fig.2, and Fig.3), only one or two of them will contribute to the specific B * q → DM decays. The explicit amplitudes for the concrete B * q → DP , DV decays have been collected in the Appendixes A and B, and the building blocks in the Appendixes C, D and E. According to the polarization relations between the initial and final vector mesons, the amplitudes for the B * q → DV decays can generally be decomposed into the following structures [44][45][46][47],…”

Fullerenes in the IC 348 star cluster of the Perseus Molecular Cloud

“…the low spatial resolution studies of AME (Anomalous Microwave Emission) in Perseus Genova-Santos et al (2015). However as shown in the study by Sun et al (2008) large variations in the far UV (FUV) radiation field can exist in the Perseus star-forming region IC 348 where the stars of this work are located. In Table 3 of the latter paper the variations of the intensity of the FUV radiation field are quantified using different approaches.…”

“…The values obtained for LRLL 1, LRLL2 and LRLL 58 are 4 x 10 −7 , 2 x 10 −7 and 0.5 x 10 −7 W m −2 sr −1 , respectively, giving C60 column densities of 2, 1 and 0.5 x 10 14 cm −2 for each target. Using the expression f C 60 C = n(C60) x 60 / (N(H) x [C]) where [C] is the carbon to hydrogen ratio adopted as 1.6 x 10 −4 by Sofia et al (2004), and taking N(H)= 4.8 x 10 22 from Sun et al (2008) for the central part of the IC 348 cluster, it yields abundances of the gas phase carbon locked in C60 of 1.6 x 10 −3 , 0.8 x 10 −3 and 0.4 x 10 −3 , for stars LRLL 1, 2 and 58, respectively. These values of 0.16-0.04 % compare well with previously reported values in star-forming regions (Castellanos et al 2014;Berné et al 2017).…”

Neoclassical toroidal viscosity torque in tokamak edge pedestal induced by external resonant magnetic perturbation

“…The evaluation of NTV torque density depends on the calculation of the perturbed distribution function f 1 and the perturbed magnetic field strength δB along the distorted magnetic surfaces. NTV torque density profile can be written as [13,38,39]:…”

“…The rest of definitions and the detailed solutions of the above BDKE implemented in the NTVTOK code, both analytical and numerical, can be found in [13,27,38,39]. The calculation of b n , which is the n-th toroidal Fourier component of the perturbed magnetic field strength δB, is described in next subsection (Sec.…”