If the top quark were less massive than the W boson, then W-boson decay into a top quark and a bottom quark could be the predominant mode of top-quark production. Outline 1 Top-Quark Pair Production at Hadron Colliders 2 NNLO Virtual Corrections The Quark-Antiquark Annihilation Channel The Gluon-Gluon Fusion Channel 3 Conclusions and Outlook. Top quark mass effects in HJ production at NLO Matthias Kerner 1. Figure 6 shows the most recent measurements for the cross section of ttbar production at difference CM energies, while Figure 7 shows a similar graph for single top quark production. Right: the observed running of the top-quark mass compared to the solution of the RGEs at one-loop precision. Top quark pairs at two loops and Reduze2 Andreas von Manteuffel 1. At the one-loop level, all the imaginary part of the amplitude originates from G(0) above the threshold, E ≥ 0. UCould you tell me, step by step, how gluons form virtual top or bottom quark loop. Three Loop Top Quark Contributions to the ρ Parameter M. Faisst, J.H. One-Loop Calculations and the Mass of the Top Quark BSc. Top quark pair production at NNLO Top quark pair production has been studied in detail both at the Tevatron and the LHC.
Production properties of the top quark By comparing the measurement with the theoretical calculation at a given mass, the Standard Model can be probed for deviations. In order to match the experimental precision, theoretical predictions beyond the next-to-leading order (NLO) are necessary [1].
Flavor changing neutral current (FCNC) interactions for a top quark t decays into Xq with X represents a neutral gauge or Higgs boson, and q a up- or charm-quark are highly suppressed in the Standard Model (SM) due to the Glashow–Iliopoulos–Miami mechanism. Two-Loop Corrections to Top-Quark Pair Production Andrea Ferroglia Johannes Gutenberg Universita¨t Mainz Padova, June 25, 2009. Introduction One of the major goals of the physics program at the LHC is the detailed study of the properties of the Higgs boson. Download Citation | Top quark pairs at two loops and Reduze 2 | We report on progress for the analytical calculation of the two-loop corrections to top quark pair production at hadron colliders. At depends on the scatter- ing angle θ, while Bt is independent of θ because only the spin-singlet tt¯ state contributes at this order. The same is true for the masses of the quarks. Title: Top Quark Loop Corrections to the Neutral Higgs Boson Production at the Fermilab Tevatron Authors: Chong-Sheng Li (PKU), Shou-Hua Zhu (ITP) (Submitted on 22 Jan 1998 ( v1 ), last revised 21 Oct 1998 (this version, v3)) The Top Quark A particle which tends to stick out... Andrea Ferroglia (Mainz U.) The UA1 experiment at CERN reported some indication of that process 4 4. Credit: CERN. μ ref = 476 GeV (purple circle) is the mean of the second mass bin. The simultaneous dependence on the mass of the Higgs boson M H and the mass of the top quark m t is obtained from expansions in the range of M H around m t and in the limit M H ≫ m t . Although approximations based on an expansion in powers of 1/m 2 t can lead to poor high-energy behavior, an exact treatment of top-quark loops demonstrates that their effect is small and has limited phenomenological interest. To achieve this, accurate theoretical predictions of the various production and decay channels of the Higgs boson are required. The radiative corrections to the top-quark pole mass are known in QCD up to three-loop order [6][7][8][9] and in the electroweak sector up to two loops [10][11][12][13][14][15]. We present results for the three-loop top quark contributions to the ρ parameter in the limit of large top quark mass. I want to know how gluons form these virtual top or bottom quark loop. represents the contribution from the soft-momentum loop where the top-quarks can be on-shell. The coupling between quarks and gluons depends strongly on the energy scale of the process. Ku¨hn, T. Seidensticker, and O. Veretin Institut fu¨r Theoretische Teilchenphysik, Universit¨at Karlsruhe, D-76128 Karlsruhe, Germany Abstract We present results for the three-loop top quark contributions to the ρ parameter in the limit of large top quark mass. M.P.A. I know the Feynmann diagrams for the creation of those loops but I do not understand those diagrams. ELSEVIER Physics Letters B 391 (1997) 429-433 16 January 1997 PHYSICS LETTERS B Top quark loop corrections to the decay H+ ---+ hOW+ in the two-Higgs doublet model R. Santos a, l, A. BarroSO a, L. Bitcher b,2 a Dept.