3,571 research outputs found
One-side Forward-backward Asymmetry in Top Quark Pair Production at CERN Large Hadron Collider
Both D0 and CDF at Tevatron reported the measurements of forward-backward
asymmetry in top pair production, which showed possible deviation from the
standard model QCD prediction. In this paper, we explore how to examine the
{\em same} higher-order QCD effects at the more powerful Large Hadron Collider.Comment: 4 pages, 6 figures, Refs added, published versio
Deci-weak at Tevatron and LHC
Recently Tevatron released their measurements on invariant mass spectrum of
electron/positron, as well as the di-jet arising from WW+WZ production with one
W leptonically decay. Though the statistics is not significant, there are two
bumps around 240 GeV and 120-160 GeV respectively. We proposed that the two
bumps correspond to the extra light gauge bosons and ,
which couple with quarks with the deci-weak strength. In this brief report, we
also simulated di-jet invariant mass distribution at the current running LHC.Comment: 8 pages, 3 EPS figures, ref added, figures update
New Color-Octet Vector Boson Revisit
Motivated by CDF recent measurements on di-jet invariant mass spectrum where
di-jet is associated production with charged leptons () and missing
energy, we re-examine the previous proposed massive color-octet
axial-vector-like boson . Our simulation showed that the di-jet bump
around 120-160 GeV can be induced by with effective coupling (q represents the quark other than top and is the
strong coupling constant). Moreover our numerical investigation indicated that
the top quark forward-backward asymmetry can be reproduced without
distorting shape of differential cross section ,
provided that the and top quark coupling is appropriately chosen (). Our results also showed that the
theoretical as functions of and can be
consistent with data within and respectively.Comment: 8 pages, 3 EPS figure
One-side forward-backward asymmetry at the LHC
Forward-backward asymmetry is an essential observable to study
the nature of coupling in the standard model and physics beyond the standard
model, as shown at LEP and Tevatron. As a proton-proton collider, the LHC does
not have the preferred direction contrary to her counterpart, namely, LEP and
Tevatron. Therefore is not applicable at the LHC. However for the
proton the momentum of valence quark is usually larger than that of the sea
quark. Utilizing this feature we have defined a so-called one-side
forward-backward asymmetry for the top quark pair production at
LHC in the previous work. In this paper we extend our studies to the charged
leptons and bottom quarks as the final states. Our numerical results show that
at the LHC can be utilized to study the nature of the couplings
once enough events are collected.Comment: 19 pages, 7 figures, 1 table, published versio
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