3,907 research outputs found
Transverse momentum resummation in soft-collinear effective theory
We present a universal formalism for transverse momentum resummation in the
view of soft-collinear effective theory (SCET), and establish the relation
between our SCET formula and the well known Collins-Soper-Sterman's pQCD
formula at the next-to-leading logarithmic order (NLLO). We also briefly
discuss the reformulation of joint resummation in SCET.Comment: 23 pages, 7 figures; version to appear in Phys. Rev.
Search for anomalous top quark production at the early LHC
We present a detailed study of the anomalous top quark production with
subsequent decay at the LHC induced by model-independent flavor-changing
neutral-current couplings, incorporating the complete next-to-leading order QCD
effects. Our results show that, taking into account the current limits from the
Tevatron, the LHC with TeV may discover the anomalous coupling at
5 level for a very low integrated luminosity of 61 pb. The
discovery potentials for the anomalous couplings at the LHC are examined in
detail. We also discuss the possibility of using the charge ratio to
distinguish the and couplings.Comment: 4 pages, 3 figures, version appears in Phys. Rev. Let
Threshold Resummation Effects in Direct Top Quark Production at Hadron Colliders
We investigate the threshold-enhanced QCD corrections to the cross sections
for direct top quark productions induced by model-independent flavor changing
neutral current couplings at hadron colliders. We use the soft-collinear
effective theory to describe the incoming massless partons and use the heavy
quark effective theory to treat the top quark. Then we construct the flavor
changing operator based on the above effective theories, and resum the large
logarithms near threshold arising from soft gluon emission. Our results show
that the resummed QCD corrections further enhance the next-to-leading order
cross sections significantly. Moreover, the resummation effects vastly reduce
the dependence of the cross sections on the renormalization and factorization
scales, especially in cases where the next-to-leading order results behave
worse than the leading order results. Our results are more sensitive to the new
physics effects. If signals of direct top quark production are found in future
experiments, it is more appropriate to use our results as the theoretical
inputs for extracting the anomalous couplings.Comment: 5 pages, 4 figures, use revtex4 and amsmath; version to appear in
Phys. Rev.
- …