Tt Production Research Articles

Adequacy, fluency and cognitive processes: evidence from translating English news articles into Arabic

ABSTRACT This article reports on an empirical study on cognitive processes [i.e. (dis) fluency, temporal management of the translation process, and revision] and their relationship with fluency and adequacy. Based on Jakobsen and Schou’s (1999) computational model of human translation, the author utilizes keylogging data retrieved from a Translog-II-based task to investigate the cognitive processes behind Arab translator trainees’ translations of an English news article into Arabic and unfold whether these processes predict fluency and adequacy (N = 32). Results demonstrate trainees’ segmentation of a news article into frequent short lexical segments manifested in the mean translation units (M = 141.34, SD = 44.37), reliance on online revision over end revision, and temporal delay in the drafting stage. Multiple-line regression analysis shows that translation quality is predicted by revision time, orientation time, and translation speed in addition to a positive association between translation units and translation adequacy. According to the findings, translation trainees should be equipped with ST comprehension, and TT production and revision skills.

The role of creativity on the translation of motion verbs: data on the translation product and process

The present study researches the correlation between translators’ creative personality and their behaviour by using a combination of psychological, key-logging and screen-recording methods as well as the evaluation of participants’ translation output. Participants were asked to translate a literary text without knowing that it posed the additional challenge of transferring manner of motion verbs into Spanish. The experiment correlated the participants’ scores on a validated creativity test (i.e., CREA, Corbalán Berná et al., 2003) with their scores on process indicators of fluency as one of the key dimensions of creativity as well as product indicators of flexibility, novelty, and accuracy. To this purpose, the logging tool Inputlog was used to measure dwell ratio, total translation time, time interval between ST processing and TT production and time devoted to revision. The screen recording software CamStudio was also used to analyse participants’ creativity in searching and retrieving information. Although few significant statistical results were found, our study suggests that creative translators’ potential can be traced both in their translation product and process.

Resummation of soft and Coulomb corrections for toverline{t}h production at the LHC

In this paper, a combined resummation of soft and Coulomb corrections is performed for the associated production of the Higgs boson with a top quark pair at the LHC. We illustrate the similarities and critical differences between this process and the toverline{t} production process. We show that up to the next-to-leading power, the total cross section for toverline{t}h production admits a similar factorization formula in the threshold limit as that for tt production. This fact, however, is not expected to hold at higher powers. Based on the factorization formula, we perform the resummation at the improved next-to-leading logarithmic accuracy, and match to the next-to-leading order result. This allows us to give NLL′+NLO predictions for the total cross sections at the LHC. We find that the resummation effects enhance the NLO cross sections by about 6%, and significantly reduce the scale dependence of the theoretical predictions.

Search for new phenomena in events with same-charge leptons and b-jets in pp collisions at sqrt{s}=13 TeV with the ATLAS detector

A search for new phenomena in events with two same-charge leptons or three leptons and jets identified as originating from b-quarks in a data sample of 36.1 fb−1 of pp collisions at sqrt{s}=13 TeV recorded by the ATLAS detector at the Large Hadron Collider is reported. No significant excess is found and limits are set on vector-like quark, four-top-quark, and same-sign top-quark pair production. The observed (expected) 95% CL mass limits for a vector-like T- and B-quark singlet are mT > 0.98 (0.99) TeV and mB > 1.00 (1.01) TeV respectively. Limits on the production of the vector-like T5/3-quark are also derived considering both pair and single production; in the former case the lower limit on the mass of the T5/3-quark is (expected to be) 1.19 (1.21) TeV. The Standard Model four-top-quark production cross-section upper limit is (expected to be) 69 (29) fb. Constraints are also set on exotic four-top-quark production models. Finally, limits are set on same-sign top-quark pair production. The upper limit on uu → tt production is (expected to be) 89 (59) fb for a mediator mass of 1 TeV, and a dark-matter interpretation is also derived, excluding a mediator of 3 TeV with a dark-sector coupling of 1.0 and a coupling to ordinary matter above 0.31.

An effective, simple and low-cost pretreatment for culture clarification in tetanus toxoid production

Chemically inactivated tetanus toxin (tetanus toxoid, TT), purified from cultures of a virulent Clostridium tetani strain, is the active pharmaceutical ingredient of anti-tetanus vaccines. Culture clarification for TT production and is usually performed by filtration-based techniques. Final clarification of the culture supernatant is achieved by passage through 0.2 µm pore size filtering membranes. Large particles removal (primary clarification) before final filtration (secondary clarification) reduces costs of the overall clarification process. With this aim, chitosan-induced particle aggregation was assessed as an alternative for primary clarification. Three chitosan variants were tested with similar results. Optimal clarification of culture supernatant was achieved by the addition of 8 mg chitosan per l of culture. Extrapolation analysis of filter sizing results indicate that 100 l of chitosan-treated supernatant can be finally filtered with a 0.6 m2 normal filtration cartridge of 0.45 + 0.2 µm pore size. The clarified material is compatible with current standard downstream processing techniques for TT purification. Thus, chitosan-induced particle aggregation is a suitable operation for primary clarification.

Top quark pair properties using the ATLAS detector at the LHC

The latest measurements of the properties of the top quark using the ATLAS experiment are presented. The top quark mass is one of the fundamental parameters of the Standard Model. A new measurement using the template method in dilepton events in which the event selection was optimised to achieve the smallest total uncertainty is presented. It is combined with a measurement on a multi-dimensional template fit that can constrain the uncertainties on the energy measurements of jets. In addition, measurements aiming to measure the mass in a well-defined scheme are presented. The top quark pair charge asymmetry is an asymmetry predicted to occur beyond leading-order QCD in the Standard Model, and may be significantly enhanced by the presence of new physics. The tt production charge asymmetry is measured inclusively and differentially using the 8 TeV ATLAS datasets in the dilepton channel and with lepton+jets events including boosted topology. Making use of the large number of top quark pairs collected, we also present measurements of the spin correlation between top and anti-top quarks and discuss their sensitivities to new physics.

Precision measurement of the top quark mass in lepton + jets final States.

We measure the mass of the top quark in lepton+jets final states using the full sample of pp collision data collected by the D0 experiment in Run II of the Fermilab Tevatron Collider at sqrt[s] = 1.96 TeV, corresponding to 9.7 fb(-1) of integrated luminosity. We use a matrix element technique that calculates the probabilities for each event to result from tt production or background. The overall jet energy scale is constrained in situ by the mass of the W boson. We measure m(t) = 174.98 ± 0.76 GeV. This constitutes the most precise single measurement of the top-quark mass.

Measurement of the top quark pair production charge asymmetry in proton-proton collisions at $ \sqrt{s} $ = 7 TeV using the ATLAS detector

This letter presents a measurement of the top quark pair (tt) production charge asymmetry Ac using 4.7 fb-1 of proton-proton collisions at a centre-of-mass energy of 7 TeV collected by the ATLAS detector at the LHC. A tt-enriched sample of events with a single lepton (electron or muon), missing transverse momentum and at least four high transverse momentum jets, of which at least one is tagged as coming from a b-quark, is selected. A likelihood fit is used to reconstruct the tt event kinematics. A Bayesian unfolding procedure is employed to estimate Ac at the parton-level. The measured value of the tt production charge asymmetry is 0.006 +/- 0.010, where the uncertainty includes both the statistical and the systematic components. Differential Ac measurements as a function of the invariant mass, the rapidity and the transverse momentum of the tt-system are also presented. In addition, Ac is measured for a subset of events with large tt velocity, where physics beyond the Standard Model could contribute. All measurements are consistent with the Standard Model predictions.

Single top production in association with aZboson at the LHC

We present results for the production of a Z boson in association with single top at next-to-leading order (NLO), including the decay of the top quark and the Z boson. This electroweak process gives rise to the trilepton signature l+l-l'+- + jets + missing energy. We present results for this signature and show that the rate is competitive with the contribution of the mixed strong and electroweak production process, ttZ. As such it should be observable in the full data sample from LHC running at $\sqrt{s}=8$ TeV. The single top + Z process is a hitherto unconsidered irreducible background in searches for flavour changing neutral current decays of the top quark in tt production. For a selection of cuts used at the LHC involving a b-tag it is the dominant background. In an appendix we also briefly discuss the impact of NLO corrections on the related tH process.

Top pair production at ATLAS

An overview of latest ATLAS measurements of top pair ( tt ) production in proton-proton collisions at the LHC at centre-of-mass energies of 7 and 8 TeV is presented. Measurements of the tt production cross section (σ tt ) in various decay channels, including analyses of differential σ tt distributions and a study of jet multiplicity in tt production, as well as searches for tt resonances using boosted top techniques and standard methods, are discussed.

Constraining unparticles from top physics at the Tevatron

We study and analyze the recent observations of the top pair production $\sigma (p\bar p\to t \bar t)$ at TeVatron through flavor conserving and flavor violating channels ${\it via}$ vector and tensor unparticles. The unparticle sector is considered with the possibility of being a color singlet or octet. The modified unparticle propagator is used to investigate the contribution of these unparticles to the observed $A_{FB}^{t\bar t}$ (forward backward asymmetry in top pair production) and the spin correlation at TeVatron. We have also studied the impact of the flavor violating couplings of unparticles to the third generation quarks on (a) pair production of same sign tops/antitops $\sigma (p\bar p\to tt+\bar t \bar t)$ at TeVatron and (b) the partial top decay width for $\Gamma_{\cal U}(t\to u\,{\cal U}^V)$. We find that a large region of parameter space is consistent with the measurements of \tt production cross-section, \afbt and spin correlation coefficient at TeVatron and observe that the top decay width measurement constrains the flavor violating coupling of vector unparticles more severely than the same sign top/antitop production at TeVatron. We also predict the best point-set in the model parameter space for specific choices of \du corresponding to $\chi^2_{\rm min}$ evaluated using the \mttb spectrum of \afbt from the data set of Run II of TeVatron at the integrated luminosity 8.7 fb$^{-1}$. Our results and analysis are consistent even with unparticle theories having broken scale invariance as long as the infrared cut-off scale is much less than the top pair production threshold.

Charged Higgs observability through associated production with W ± at a muon collider

The observability of a charged Higgs boson produced in association with a W boson at future muon colliders is studied. The analysis is performed within the MSSM framework. The charged Higgs is assumed to decay to tb and a fully hadronic final state is analyzed, i.e., mu+mu- \rightarrow H\pmW\mp \rightarrow tbW \rightarrow WbbW \rightarrow jjjjbb. The main background is tt production in fully hadronic final state which is an irreducible background with very similar kinematic features. It is shown that although the discovery potential is almost the same for a charged Higgs mass in the range 200 GeV < mH\pm < 400 GeV, the signal significance is about 1sigma for tanbeta = 50 at integrated luminosity of 50 fb-1. The signal rate is well above that at e+e- linear colliders with the same center of mass energy and enough data (O(1 ab-1)) will provide the same discovery potential for all heavy charged Higgs masses up to mH\pm \sim 400 GeV, however, the muon collider cannot add anything to the LHC findings.

Littlest Higgs model withTparity and top quark pair production at LHC

We consider the top-quark pair production at the upcoming LHC and investigate the contributions of the new particles to the related observables within the framework of the littlest Higgs model with T-parity(LHT). It is found that the LHT model can generate significant corrections to the tt production cross section and their spin correlations.

Heavy-quark pair production in polarized photon-photon collisions at next-to-leading order: Fully integrated total cross sections

We consider the production of heavy-quark pairs in the collisions of polarized and unpolarized on-shell photons and present, in analytic form, the fully integrated total cross sections for total photon spins J{sub z}=0, {+-}2 at next-to-leading-order in QCD. Phenomenological applications include bb production, which represents an irreducible background to standard-model intermediate-mass Higgs-boson production, as well as tt production.

NLO QED contributions to top-pair production at hadron colliders

Electroweak one-loop calculations for production of top-quark pairs at colliders are completed by providing the missing QED type contributions from real and virtual photons, where also effects from interference between QED and QCD contributions have to be taken into account. Moreover, photon-induced tt production is included as another partonic channel.

High energy neutrinos from neutralino annihilations in the Sun

Neutralino annihilations in the Sun to weak boson and top-quark pairs lead to high-energy neutrinos that can be detected by the IceCube and KM3 experiments in the search for neutralino dark matter. We calculate the neutrino signals from real and virtual WW, ZZ, Zh, and tt production and decays, accounting for the spin dependences of the matrix elements, which can have important influences on the neutrino energy spectra. We take into account neutrino propagation including neutrino oscillations, matter-resonance, absorption, and {nu}{sub {tau}} regeneration effects in the Sun and evaluate the neutrino flux at the Earth. We concentrate on the compelling focus point (FP) region of the supergravity model that reproduces the observed dark matter relic density. For the FP region, the lightest neutralino has a large bino-Higgsino mixture that leads to a high neutrino flux and the spin-dependent neutralino capture rate in the Sun is enhanced by 10{sup 3} over the spin-independent rate. For the standard estimate of neutralino captures, the muon signal rates in IceCube are identifiable over the atmospheric neutrino background for neutralino masses above M{sub Z} up to 400 GeV.

Probing anomalous Wtb couplings in top pair decays

We investigate several quantities, defined in the decays of top quark pairs, which can be used to explore non-standard Wtb interactions. Two new angular asymmetries are introduced in the leptonic decay of top (anti)quarks. Both are very sensitive to anomalous Wtb couplings, and their measurement allows for a precise determination of the W helicity fractions. We also examine other angular and energy asymmetries, the W helicity fractions and their ratios, as well as spin correlation asymmetries, analysing their dependence on anomalous Wtb couplings and identifing the quantities which are most sensitive to them. It is explicitly shown that spin correlation asymmetries are less sensitive to new interactions in the decay of the top quark; therefore, when combined with the measurement of other observables, they can be used to determine the tt spin correlation even in the presence of anomalous Wtb couplings. We finally discuss some asymmetries which can be used to test CP violation in tt production and complex phases in the effective Wtb vertex.

Finite width and irreducible background effects to tt production at gamma gamma next linear colliders

We study the complete process gamma gamma to bbW+W- using exact matrix element computations at tree-level, at a square root s=500 GeV e+e- linear collider of the next generation. Incoming photons produced via back-scattering of laser light are considered. Sizable effects due to the finite width of the top quark as well as to the irreducible background to tt production and decay are predicted.

New third-family flavor physics: vertex corrections

As described previously, a new massive gauge boson ( X) coupling only to the third family produces a tantalizing pattern of deviations away from the standard model. These include increasing Γ b Γ h and decreasing the α s ( M z ) extracted from Γ h Γ l . We review the status of these X- Z mixing effects. We then calculate X boson induced vertex corrextions to Z partial decay widths and to tt production in p p colliders.

Reconciling the LEP and SLAC measurements of sin 2θ w

We consider whether a discrepancy between the SLAC and LEP measurements of sin 2θ w can be explained by new physics. We find that only the contribution of a new neutral gauge boson, Z′, nearly degenerate with the Z can affect the SLAC measurement while leaving the LEP observables almost unaffected. We briefly discuss possible signals for this new gauge boson, including changes in the Z lineshape when measured with polarized electrons, small change in R b , A FB e , and larger changes in two jet and tt production at hadron colliders.