第二届微扰量子场论研讨会

We give comprehensive analyses for event shape observables in electron-positron annihilation by using the Principle of Maximum Conformality (PMC). Conventionally the renormalization scale and theoretical uncertainties in event shape observables are often evaluated by setting the scale to the center-of-mass energy $\sqrt{s}$. The event shape distributions using this conventional scale setting...

We suggest a novel single-scale setting approach under the principal of maximum conformality (PMC) for eliminating the conventional renormalization scheme-and-scale ambiguities following the idea of intrinsic conformality. It has been shown that the intrinsic conformality ensures the scale-invariance at each order, and vice versa. We call this newly suggested single-scale method as the...

The single-top production via electroweak interactions is important for studying the top quarks. One can further identify three channels in the single-top production mode, namely the t-channel, the tW associated production, and the s-channel, in the order of descending cross section at the LHC. The complete NNLO QCD corrections to single-top production involve complicated two-loop Feynman...

In the framework of nonrelativistic QCD (NRQCD) factorization and thanks to AMflow method, we take finite charm mass and light-by-light effects on Upsilon decay into consideration at three loop level on the base that we confirm the existing three-loop results in literature with high numerical accuracy. In addition, we obtain a new piece of 3-loop contribution to the anomalous dimension related...

We propose a strategy to study the analytic structure of Feynman parameter integrals where singularities of the integrand consist of rational irreducible components. At the core of this strategy is the identification of a selected stratum of discontinuities induced from the integral, together with a geometric method for computing their singularities on the principal sheet. For integrals that...

In the framework of the soft-collinear effective theory, we demonstrate that the leading-power heavy-to light baryonic form factors at large recoil obey the heavy quark and large energy symmetries. Symmetry breaking effects are suppressed by Λ/mb or Λ/E, where Λ is the hadronic scale, mb is the b quark mass and E ∼ mb is the energy of light baryon in the final state. At leading order, the...

Ditauonium is an exotic atom, and that is a bound state consisting of opposite-sign $\tau$ leptons by the QED interaction. We consider an impact of tauonium($1^{3}S_{1}$, $2^{3}S_{1}$ and $3^{3}S_{1}$) as an intermediates on $e^+e^-\to\mu^+\mu^-$ process. And smearing effect has a influence on signal at different experimental resolution. We estimate event distribution at $1fb^{-1}$ integrated...