scholarly journals Next-to-leading order QCD corrections totZassociated production via the flavor-changing neutral-current couplings at hadron colliders

2011 ◽  
Vol 83 (11) ◽  
Author(s):  
Bo Hua Li ◽  
Yue Zhang ◽  
Chong Sheng Li ◽  
Jun Gao ◽  
Hua Xing Zhu
2004 ◽  
Vol 19 (06) ◽  
pp. 405-419 ◽  
Author(s):  
NIKOLAOS KIDONAKIS

We review recent advances in the calculation of higher-order soft-gluon corrections for a variety of QCD, Higgs, and SUSY processes in hadron colliders. A unified approach and master formulas for next-to-next-to-leading order soft and virtual corrections are discussed. We present some applications of the formalism to top quark pair production at the Tevatron and the LHC, top production via anomalous couplings in flavor-changing neutral-current processes, W boson hadroproduction at large transverse momentum, and charged Higgs production at the LHC.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jin Sun ◽  
Yu Cheng ◽  
Xiao-Gang He

Abstract General flavor changing Goldstone boson (GB) interactions with fermions from a spontaneous global U(1)G symmetry breaking are discussed. This GB may be the Axion, solving the strong QCD CP problem, if there is a QCD anomaly for the assignments of quarks U(1)G charge. Or it may be the Majoron, producing seesaw Majorana neutrino masses by lepton number violation, if the symmetry breaking scale is much higher than the electroweak scale. It may also, in principle, play the roles of Axion and Majoron simultaneously as far as providing solution for the strong CP problem and generating a small Majorana neutrino masses are concerned. Great attentions have been focused on flavor conserving GB interactions. Recently flavor changing Axion and Majoron models have been studied in the hope to find new physics from rare decays in the intensity frontier. In this work, we will provide a systematic model building aspect study for flavor changing neutral current (FCNC) GB interactions in the fermion sectors, or separately in the quark, charged lepton and neutrino sectors and will identify in detail the sources of FCNC interactions in a class of beyond standard model with a spontaneous global U(1)G symmetry breaking. We also provide a general proof of the equivalence of using physical GB components and GB broken generators for calculating GB couplings to two gluons and two photons, and discuss some issues related to spontaneous CP violation models. Besides, we will also provide some details for obtaining FCNC GB interactions in several popular models, such as the Type-I, -II, -III seesaw and Left-Right symmetric models, and point out some special features in these models.


2004 ◽  
Vol 596 (3-4) ◽  
pp. 173-183 ◽  
Author(s):  
I. Abt ◽  
M. Adams ◽  
H. Albrecht ◽  
A. Aleksandrov ◽  
V. Amaral ◽  
...  

2007 ◽  
Vol 22 (25n28) ◽  
pp. 2121-2129 ◽  
Author(s):  
XIAO-GANG HE ◽  
HO-CHIN TSAI ◽  
TONG LI ◽  
XUE-QIAN LI

We study possible observational effects of scalar dark matter, the darkon D, in Higgs h and top quark t decay processes, h → DD and t → cDD in the minimal Standard Model (SM) and its two Higgs doublet model (THDM) extension supplemented with a SM singlet darkon scalar field D. We find that the darkon D can have a mass in the range of sub-GeV to several tens of GeV, interesting for LHC and ILC colliders, to produce the required dark matter relic density. In the SM with a darkon, t → cDD only occurs at loop level giving a very small rate, while the rate for Higgs decay h → DD can be large. In THDM III with a darkon, where tree level flavor changing neutral current (FCNC) interaction exists, a sizable rate for t → cDD is also possible.


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