2,834 research outputs found
Top Quark Yukawa Couplings and New Physics
We discuss associated production of a Higgs boson with a pair of
quarks at a future high energy collider. The process is particularly sensitive to the presence of new physics and we
consider the MSSM and models with extra dimensions at the scale as
examples.Comment: Talk given at the 5th International Collider Workshop (LCWS 2000),
Fermilab, Batavia, Il, Oct 24-28, 200
Next-to-Leading Order Results for t-tbar-h Production at the Tevatron
We compute the O(alpha_s^3) total cross section for the process (p pbar -> t
tbar h) in the Standard Model, at \sqrt{s}=2 TeV. The next-to-leading order
corrections drastically reduce the renormalization and factorization scale
dependence of the Born cross section and slightly decrease the total cross
section for renormalization and factorization scales between m_t and 2m_t.Comment: 5 pages, 5 figures, REVTeX, submitted to Phys. Rev. Let
Hard-photon production with b jets at hadron colliders
We present total and differential cross sections for the production of a hard
photon with up to two b jets at both the Tevatron with center-of-mass energy
1.96 TeV and the Large Hadron Collider with center-of-mass energy 8 TeV,
including Next-to-Leading Order (NLO) QCD corrections and full b-quark mass
effects. We study the theoretical uncertainty due to the residual
renormalization- and factorization-scale dependence and explain its origin on
the basis of the different subprocesses contributing to the NLO cross section.
We specifically address the case of the production of a hard photon with at
least one b jet and compare the NLO QCD predictions in both the Four- and
Five-Flavor-Number Schemes to the experimental measurements obtained by CDF and
D0.Comment: 33 pages, 50 postscript figure
Scheme Independence of the Effective Hamiltonian for and Decays
We present a calculation of the effective weak Hamiltonian which governs and transitions in two different
renormalization schemes (NDR and HV). In the leading logarithmic approximation,
we show that the coefficients of the effective Hamiltonian are scheme
independent only when one takes correctly into account the scheme dependence of
one- and two- loop diagrams. We demonstrate that in NDR there are contributions
which were missed in previous calculations. These contributions are necessary
to obtain scheme independent coefficients in the final results.Comment: 16 pp + 5 figures not included (available by anonymous ftp at
amisan.iss.infn.it (141.108.15.215), directory /ftp/bsgamma), LaTeX, LPTENS
93/28, ROME 93/958, ULB-TH 93/0
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