2,302 research outputs found
Next-to-next-to-next-to-leading-order soft-gluon corrections in hard-scattering processes near threshold
I present a unified calculation of soft-gluon corrections to hard-scattering
cross sections through next-to-next-to-next-to-leading order (NNNLO). Master
formulas are derived, from a threshold resummation formalism, that can be
applied to total and differential cross sections for hard-scattering processes
in hadron colliders. I also present numerical results for charged Higgs
production at the LHC where these corrections are large, and for top quark
production at the Tevatron where these corrections greatly reduce the scale
dependence of the cross section.Comment: 22 pages, 3 figure
Collider Signature of T-quarks
Little Higgs models with T Parity contain new vector-like fermions, the T-odd
quarks or "T-quarks", which can be produced at hadron colliders with a
QCD-strength cross section. Events with two acoplanar jets and large missing
transverse energy provide a simple signature of T-quark production. We show
that searches for this signature with the Tevatron Run II data can probe a
significant part of the Little Higgs model parameter space not accessible to
previous experiments, exploring T-quark masses up to about 400 GeV. This reach
covers parts of the parameter space where the lightest T-odd particle can
account for the observed dark matter relic abundance. We also comment on the
prospects for this search at the Large Hadron Collider (LHC).Comment: 5 pages, 3 figure
Angular distribution of Drell-Yan process at hadron colliders to NLO-QCD in models of TeV scale gravity
In TeV scale gravity models, for dilepton production at hadron colliders, we
present the NLO-QCD corrections for the double differential cross section in
the invariant mass and scattering angle. For both ADD and RS models, the
quantitative impact of QCD corrections for extra dimension searches at LHC and
Tevatron are investigated. We present the K-factors for both ADD and RS models
at LHC and Tevatron. Inclusion of QCD corrections to NLO stabilises the cross
section with respect to scale variations.Comment: 35 pages, 12 figures, version to appear in NP
B-Physics at the Tevatron (Proceedings of PASCOS2010)
We report on recent B-Physics results from the Tevatron. The topics covered
include measurement of the polarization amplitudes in ,
the search for rare flavor-changing neutral-current decays, CP violation in
and semileptonic decays, and a new measurement
of the like-sign asymmetry in dimuon events.Comment: 6 pages, proceedings paper, 16th International Symposium on
Particles, Strings, and Cosmology, Valencia, Spain, July 19 - 23, 201
Angular correlations in single-top-quark and Wjj production at next-to-leading order
I demonstrate that the correlated angular distributions of final-state
particles in both single-top-quark production and the dominant Wjj backgrounds
can be reliably predicted. Using these fully-correlated angular distributions,
I propose a set of cuts that can improve the single-top-quark discovery
significance by 25%, and the signal to background ratio by a factor of 3 with
very little theoretical uncertainty. Up to a subtlety in t-channel
single-top-quark production, leading-order matrix elements are shown to be
sufficient to reproduce the next-to-leading order correlated distributions.Comment: 22 pages, 23 figs, RevTex4, fixed typos, to appear in Phys. Rev.
Using Charge Asymmetries to Measure Single Top Quark Production at the LHC
Electroweak production of single top quarks is an as-yet-unverified
prediction of the Standard model, potentially sensitive to new physics. Two of
the single top quark productions channels have significant charge asymmetries
at the LHC, while the much larger background from is nearly
charge-symmetric. This can be used to reduce systematic uncertainties and make
precision measurements of single top quark production.Comment: 4 pages, 1 figur
SUSY QCD one-loop effects in (un)polarized top-pair production at hadron colliders
We study the effects of O(alpha_s) supersymmetric QCD (SQCD) corrections on
the total production rate and kinematic distributions of polarized and
unpolarized top-pair production in pp and p anti-p collisions. At the Fermilab
Tevatron p anti-p collider, top-quark pairs are mainly produced via
quark-antiquark annihilation, q anti-q -> t anti-t, while at the CERN LHC pp
collider gluon-gluon scattering, g g -> t anti-t, dominates. We compute the
complete set of O(alpha_s) SQCD corrections to both production channels and
study their dependence on the parameters of the Minimal Supersymmetric Standard
Model. In particular, we discuss the prospects for observing strong,
loop-induced SUSY effects in top-pair production at the Tevatron Run II and the
LHC.Comment: 56 pages, 29 figures, RevTeX
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