6,378 research outputs found
Electroweak Radiative Corrections to and Boson Production in Hadronic Collisions
Some results of a calculation of electroweak radiative corrections to and
boson production in hadronic collisions are presented.Comment: 4 pages, LaTeX, uses sprocl.sty, 2 embedded postscript figures, to
appear in the Proceedings of the DPF96 Conferenc
Hadron collider limits on anomalous couplings
A next-to-leading log calculation of the reactions and
is presented including a tri-boson
gauge coupling from non-Standard Model contributions. Two approaches are made
for comparison. The first approach considers the tri-boson coupling
as being uniquely fixed by tree level unitarity at high energies to its
Standard Model form and, consequently, suppresses the non-Standard Model
contributions with form factors. The second approach is to ignore such
considerations and calculate the contributions to non-Standard Model tri-boson
gauge couplings without such suppressions. It is found that at Tevatron
energies, the two approaches do not differ much in quantitative results, while
at Large Hadron Collider (LHC) energies the two approaches give significantly
different predictions for production rates. At the Tevatron and LHC, however,
the sensitivity limits on the anomalous coupling of are too weak to
usefully constrain parameters in effective Lagrangian models.Comment: Revtex 23 pages + 8 figures, UIOWA-94-1
Experimental Evaluation of Steady-State Control Properties of an Electron-Bombardment Ion Thrustor
Examined in this report are the experimental steady-state gains, or changes, in beam-current output with changes in thrustor inputs for a 10-centimeter-diameter electron-bombardment ion thrustor. A general leveling off of beam current as a function of an input variable was found at the upper range of each variable, At the design operating point, the filament-heating current exhibited the greatest sensitivity, or percentage beam-current output change for a percentage change in the input (2 to 4). Accelerator voltage showed the least effect (0.04) while discharge voltage, magnetic field, and neutral propellant flow exhibited about the same sensitivity (0.4 to 0.5). Some effects of nonlinearity are shown that may require consideration in the design of a closed-loop control system
Where the law of the invisible hand fails : applying the perspectives of an economic tourist as he ventures into the heart of antediluvian economics
Abstract: Value is subjective. Pricing structures are assumed to be an expression of value, but the problem is that they do not really express a universal value. While tourists may be armed with a bundle of local currency and a supply of sunscreen to protect themselves from the elements of nature, it’s really the established institutions within the territory that pose the real threat to the sanity of the decision maker. This paper examines the role of ‘Information’ in an institutional framework with the aim of exploring the challenges that an economic tourist would be confronted with when attempting to determine the value of a commodity. This within a market which cannot be determined using typical market fundamentals. While an archetypal tourist would be capable of following a road map that may confirm his belief in the markets. However, his own interpretation of the information on that map will be challenged as he ventures further into the world of an antediluvian market where low levels of competition exist and the interaction between supply and demand would best be described as unstable. The problems that modern day economic tourists would face is greatly increased as they are confronted by new and unpredictable institutional information. This information has been developed over centuries within a culturally biased informational context regarding commodities and products in different markets. The real value of a product in an antediluvian economy is determined by the ‘value of Information’ held by the institution within that economy which would serve as a regulator of ‘value’. While value is subjective, the price set within the antediluvian economy may echo issues such as political, social and economic conditions, not reflected in the price, and thus create a flood of misperception to the aspiring tourists
Electroweak corrections to production at hadron colliders
In this paper we present the results from a calculation of the full
electroweak one-loop corrections for vector-boson pair production at
hadron colliders. The cases of proton--antiproton as well as proton--proton
collisions, at the Tevatron and the LHC, respectively, are considered. Results
are presented for the distribution of the invariant mass and for the
transverse momentum of the final-state photon. The higher-order electroweak
effects are numerically significant, in particular for probing possible
anomalous gauge-boson couplings
Higher-order QED corrections to W-boson mass determination at hadron colliders
The impact of higher-order final-state photonic corrections on the precise
determination of the W-boson mass at the Tevatron and LHC colliders is
evaluated. In the presence of realistic selection criteria, the shift in the W
mass from a fit to the transverse mass distribution is found to be about 10 MeV
in the channel and almost negligible in the
channel. The calculation, which is implemented in a Monte Carlo event generator
for data analysis, can contribute to reduce the uncertainty associated to the W
mass measurement at future hadron collider experiments.Comment: 9 pages, 2 figures, 1 table, RevTe
Vector Boson Pair Production in Hadronic Collisions at Order : Lepton Correlations and Anomalous Couplings
We present cross sections for production of electroweak vector boson pairs,
, and , in and collisions, at next-to-leading
order in . We treat the leptonic decays of the bosons in the
narrow-width approximation, but retain all spin information via decay angle
correlations. We also include the effects of and anomalous
couplings.Comment: 23 pages, 8 figures, 3 table
Improved Measurement of ttZ Couplings at the LHC
We consider QCD tt~Z production at the LHC with Z->\bar\nu\nu and
all-hadronic tt~ decays, i.e. pp -> p_T(miss)bb~+4 jets, as a tool to measure
ttZ couplings. This channel has a significantly larger cross section than those
where the Z boson decays leptonically. However, tt~, bb~+4 jet, tt~j and tt~jj
production give rise to potentially large backgrounds. We show that these
processes can be suppressed to an acceptable level with suitable cuts, and find
that adding the p_T(miss)bb~+4 jet channel to the final states used in previous
ttZ couplings analyses will improve the sensitivity by 10-60%. We also discuss
how the measurement of the ttZ couplings may constrain Little Higgs models.Comment: revtex4, 16 pages, 4 figures, 1 tabl
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
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