1,381 research outputs found
e+ e- -> t anti-t H including decays: on the size of background contributions
We present results for the lowest order cross sections, calculated with the
complete set of the standard model Feynman diagrams, of all possible detection
channels of the associated production of the top quark pair and the light Higgs
boson, which may be used for determination of the top-Higgs Yukawa coupling at
the future e+e- linear collider. We show that, for typical particle
identification cuts, the background contributions are large. In particular, the
QCD background contributions are much bigger than could be expected when taking
into account a possibly low virtuality of exchanged gluons. Moreover, we
include the initial state radiation effects and discuss the dependence of the
cross sections on the Higgs boson and top quark masses.Comment: 13 pages, 1 figure; substantially revised version, accepted for
publication in Eur.Phys.J.
On the tensor reduction of one-loop pentagons and hexagons
We perform analytical reductions of one-loop tensor integrals with 5 and 6
legs to scalar master integrals. They are based on the use of recurrence
relations connecting integrals in different space-time dimensions. The
reductions are expressed in a compact form in terms of signed minors, and have
been implemented in a mathematica package called hexagon.m. We present several
numerical examples.Comment: Latex, 7 pages, 2 eps figures. Contribution to the proceedings of
`Loops and Legs in Quantum Field Theory', April 2008, Sondershausen, German
Electroweak corrections to Higgs production through ZZ fusion at the linear collider
We present the full order alpha electroweak radiative corrections to e+e- ->
e+e-H. The computation is performed with the help of GRACE-loop. The extraction
of the full QED corrections is performed, these are quite large at threshold.
The genuine weak corrections, for the linear collider energies, when expressed
in the G_mu scheme are of order -2 to -4 for Higgs masses preferred by the
latest precision data. We also extract the m_t^2 type corrections and make a
comparison with the weak corrections for the process e+e- ->nu nu H.Comment: 16 pages and 6 figure
Electroweak-correction effects in gauge-boson pair production at the LHC
We have studied the effect of one-loop logarithmic electroweak radiative
corrections on WZ and production processes at the LHC. We present
analytical results for the leading-logarithmic electroweak corrections to the
corresponding partonic processes du -> WZ, Wgamma. Using the leading-pole
approximation we implement these corrections into Monte Carlo programs for
. We find that electroweak corrections
lower the predictions by 5-20% in the physically interesting region of large
transverse momentum and small rapidity separation of the gauge bosons.Comment: 28 pages, LaTex, 13 eps figures included; references added and
corrected typo
SUSY-QCD Corrections to Associated Production at the CERN Large Hadron Collider
We calculate the SUSY-QCD corrections to the inclusive total cross sections
of the associated production processes in the Minimal
Supersymmetric Standard Model(MSSM) at the CERN Large Hadron Collider(LHC). The
SUSY-QCD corrections can increase and decrease the total cross sections
depending on the choice of the SUSY parameters. When the SUSY-QCD
corrections increase the leading-order (LO) total cross sections significantly
for large tan (), which can exceed 10% and have the opposite
sign with respect to the QCD and the SUSY-EW corrections, and thus cancel with
them to some extent. Moreover, we also investigate the effects of the SUSY-QCD
on the differential distribution of cross sections in transverse momentum
and rapidity Y of W-boson, and the invariant mass .Comment: 24 pages, 10 figures; minor changes in references; two figures and
the corresponding disccusions added; a version to appear in PR
Supersymmetric NLO QCD Corrections to Resonant Slepton Production and Signals at the Tevatron and the LHC
We compute the total cross section and the transverse momentum distribution
for single charged slepton and sneutrino production at hadronic colliders
including NLO supersymmetric and non-supersymmetric QCD corrections. The
supersymmetric QCD corrections can be substantial. We also resum the gluon
transverse momentum distribution and compare our results with two Monte Carlo
generators. We compute branching ratios of the supersymmetric decays of the
slepton and determine event rates for the like-sign dimuon final state at the
Tevatron and at the LHC.Comment: 14 pages, LaTeX, 8 figures, uses REVTex
Near-threshold boson pair production in the model of smeared-mass unstable particles
Near-threshold production of boson pairs is considered within the framework
of the model of unstable particles with smeared mass. We describe the principal
aspects of the model and consider the strategy of calculations including the
radiative corrections. The results of calculations are in good agreement with
LEP II data and Monte-Carlo simulations. Suggested approach significantly
simplifies calculations with respect to the standard perturbative one.Comment: 15 pages, 6 figures, minor corrections, references adde
Multi-leg calculations with the GRACE/1-LOOP system. --Toward Radiative Corrections to e+e- -> mu nu-bar u d-bar --
We performed the calculation of the full O(alpha) corrections to e+e- -> mu-
nu-bar u d-bar with the help of the GRACE/1-LOOP system. We discuss how a
finite decay width introduces a serious gauge invariance breaking, particularly
for infrared 5-point functions. This is related to the way the reduction of
those functions is performed and to the treatment of the width in the
reduction.Comment: 5 pages,invited talk at "Loops & Legs in Quantum Field Theory 2004",
Zinnowitz, Germany, April 200
Full one-loop electroweak radiative corrections to single photon production in e+e-
Large scale calculation for the radiative corrections required for the
current and future collider experiments can be done automatically using the
GRACE-LOOP system. Here several results for e+e- --> 3-body processes are
presented including e+e- --> e+e-H and e+e- --> nu nubar gamma.Comment: 5 pages, contribution to ACAT03(Dec. 2003
Full order alpha electroweak corrections to double Higgs-strahlung at the linear collider
We present the full order alpha electroweak radiative corrections to the
double Higgs-strahlung process e+e- --> ZHH. The computation is performed with
the help of GRACE-loop. After subtraction of the initial state QED radiative
corrections, we find that the genuine weak corrections in the -scheme
are small for Higgs masses and energies where this cross section is largest and
is most likely to be studied. These corrections decrease with increasing
energies attaining about at TeV. The full order alpha
correction on the other hand is quite large at threshold but small at energies
around the peak. We also study changes in the shape of the invariant mass of
the Higgs pair which has been shown to be a good discriminating variable for
the measurement of the triple Higgs vertex in this reaction.Comment: 18 pages, 5 figures and 3 table
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