2,608 research outputs found
Complete Study of Hadroproduction of a Meson Associated with a Prompt
We present the first complete study of and prompt
production from single-parton scattering, including the complete
color-singlet contribution, the
electroweak contribution, the complete
nonrelativistic S-wave and P-wave color-octet contribution as well as the
feeddown contribution. Our study was motivated by the recent evidence reported
by D0 Collaboration of prompt and simultaneous production
at the Tevatron. With our complete evaluation, we are able to refine the
determination of the double parton scattering contribution made by D0
Collaboration. We find that the effective cross section characterizing the
importance of double-parton scatterings is mb at
confidence level from the D0 measurement.Comment: 11 pages, 4 figures, 4 tables; v2: journal version, update the
references and fix a few typo
Feynman Rules for the Rational Part of One-loop QCD Corrections in the MSSM
The complete set of Feynman rules for the rational part R of QCD corrections
in the MSSM are calculated at the one-loop level, which can be very useful in
the next-to-leading order calculations in supersymmetric models. Our results
are expressed in the 't Hooft-Veltman regularization scheme and in the Four
Dimensional Helicity scheme with non-anticommutating and anticommutating
strategies.Comment: version for publication, 50 pages, 6 figure
Precise QCD predictions on top quark pair production mediated by massive color octet vector boson at hadron colliders
We present a theoretical framework for systematically calculating
next-to-leading order (NLO) QCD effects to various experimental observables in
models with massive COVB in a model independent way at hadron colliders.
Specifically, we show the numerical results for the NLO QCD corrections to
total cross sections, invariant mass distribution and AFB of top quark pairs
production mediated by a massive COVB in both the fixed scale (top quark mass)
scheme and the dynamical scale (top pair invariant mass) scheme. Our results
show that the NLO QCD calculations in the dynamical scale scheme is more
reasonable than the fixed scheme and the naive estimate of the NLO effects by
simple rescaling of the LO results with the SM NLO K-factor is not appropriate.Comment: 6 pages, 5 figures, 2 tables; version published in EPJ
Top quark pair production at small transverse momentum in hadronic collisions
We investigate the transverse momentum resummation for top quark pair
production at hadron colliders using the soft-collinear effective theory and
the heavy-quark effective theory. We derive the factorization formula for
production at small pair transverse momentum, and show in detail the
procedure for calculating the key ingredient of the factorization formula: the
next-to-leading order soft functions. We compare our numerical results with
experimental data and find that they are consistent within theoretical and
experimental uncertainties. To verify the correctness of our resummation
formula, we expand it to the next-to-leading order and the
next-to-next-to-leading order, and compare those expressions with the exact
fixed-order results numerically. Finally, using the results of transverse
momentum resummation, we discuss the transverse-momentum-dependent
forward-backward asymmetry at the Tevatron.Comment: 39 pages, 7 figures, 1 table; final version in PR
Host-guest Interaction at Molecular Interfaces: Binding of Cucurbit[7]uril on Ferrocenyl Self-assembled Monolayers on Gold
Ferrocene (Fc) encapsulated cucurbit[7]uril (CB[7]) supramolecular host-guest complex (Fc@CB[7]) as a synthetic recognition pair has been widely adapted for coupling biomolecules and nanomaterials due to its ultra-high binding affinity. In this paper, we have explored the binding of CB[7] on binary ferrocenylundecanethiolate/octanethiolate self-assembled monolayer on gold (FcC11S-/C8S-Au), a model system to deepen our understanding of host-guest chemistry at molecular interfaces. It has been shown that upon incubation with CB[7] solution, the redox behavior FcC11S-/C8S-Au changes remarkably, i.e., a new pair of peaks appeared at more positive potential with narrowed widths. The ease of quantitation of surface bound-redox species (Fc+/Fc and Fc+@CB[7]/ Fc@CB[7]) enabled us to determine the thermodynamic formation constant of Fc@CB[7] at FcC11S-/C8S-Au (7.3±1.8 × 104 M-1). With time-dependent redox responses, we were able to, for the first time, deduce both the binding and dissociation rate constants, 2.8±0.3 × 103 M-1s-1 and 0.08±0.01 s-1, respectively. These results showed substantial differences both thermodynamically and kinetically for the formation of host-guest inclusion complex at molecular interfaces with respect to solution-diffused, homogenous environments
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