O(alpha_s alpha_t) (non)decoupling effects within the top-sector of the MSSM

In this paper we compute the $\mathcal{O}(\alpha_s \alpha_t)$ threshold corrections to the running strong coupling constant, the top-Yukawa coupling and the top-quark mass within the MSSM. These parameters present a non-decoupling behaviour with the supersymmetry scale $M_{\rm SUSY}$. Our numerical analysis shows that the mixed QCD-Yukawa corrections can amount to few GeV for the running top-quark mass and range at the percent level for the top-Yukawa coupling.Comment: References added; new lines in the plots displayed; more details about the calculation include

Bottom Quark Mass from Υ\Upsilon Sum Rules to O(αs3){\cal O}(\alpha_s^3)

We use the ${\cal O}(\alpha_s^3)$ approximation of the heavy-quark vacuum polarization function in the threshold region to determine the bottom quark mass from nonrelativistic $\Upsilon$ sum rules. We find very good stability and convergence of the perturbative series for the bottom quark mass in $\rm\overline{MS}$ renormalization scheme. Our final result is $\overline{m}_b(\overline{m}_b)=4.169\pm 0.008_{th}\pm 0.002_{\alpha_s}\pm 0.002_{exp}$.Comment: 23 pages, 6 figures, journal versio

Three-loop quark form factor at high energy: the leading mass corrections

We compute the leading mass corrections to the high-energy behavior of the massive quark vector form factor to three loops in QCD in the double-logarithmic approximation.Comment: 9 pages, 10 figures, LaTe

Bottom Quark Mass from Υ\Upsilon Sum Rules to O(αs3){\cal O}(\alpha_s^3)

We present the deterimination of the bottom quark mass using non-relativistic $\Upsilon$ Sum Rules at $\text{N}^3\text{LO}^*$[1]. The explicit dependence of $\overline{m}_b(\overline{m}_b)$ on the input value $\alpha_s(M_Z)$ is given for the first time.Comment: Contribution to the proceedings of "Loops and Legs in Quantum Field Theory - LL 2014", 27 April - 2 May 2014, Weimar, German