arXiv subjects

S. Errede

Publications and source records attributed to S. Errede.

7 recordsLinked to original sources

arXiv2016

Measurement of the $D^+$-meson production cross section at low transverse momentum in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV

We report on a measurement of the $D^{+}$-meson production cross section as a function of transverse momentum ($p_T$) in proton-antiproton ($p\bar{p}$) collisions at 1.96 TeV center-of-mass energy, using the full data set collected by the Collider Detector at Fermilab in Tevatron Run II and corresponding to 10 fb$^{-1}$ of integrated luminosity. We use $D^{+} \to K^-π^+π^+$ decays fully reconstructed in the central rapidity region $|y|<1$ with transverse momentum down to 1.5 GeV/$c$, a range previously unexplored in $p\bar{p}$ collisions. Inelastic $p\bar{p}$-scattering events are selected online using minimally-biasing requirements followed by an optimized offline selection. The $K^-π^+π^+$ mass distribution is used to identify the $D^+$ signal, and the $D^+$ transverse impact-parameter distribution is used to separate prompt production, occurring directly in the hard scattering process, from secondary production from $b$-hadron decays. We obtain a prompt $D^+$ signal of 2950 candidates corresponding to a total cross section $σ(D^+, 1.5 < p_T < 14.5~\mbox{GeV/}c, |y|<1) = 71.9 \pm 6.8 (\mbox{stat}) \pm 9.3 (\mbox{syst})~μ$b. While the measured cross sections are consistent with theoretical estimates in each $p_T$ bin, the shape of the observed $p_T$ spectrum is softer than the expectation from quantum chromodynamics. The results are unique in $p\bar{p}$ collisions and can improve the shape and uncertainties of future predictions.

hep-ex↗

arXiv2004

Comparison of Three-jet Events in Proton-Antiproton Collisions at Center-of-mass Energy 1.8 TeV to Predictions from a Next-to-leading Order QCD Calculation

The properties of three-jet events with total transverse energy greater than 320 GeV and individual jet energy greater than 20 GeV have been analyzed and compared to absolute predictions from a next-to-leading order (NLO) perturbative QCD calculation. These data, of integrated luminosity 86 pb^-1, were recorded by the CDF Experiment for proton-antiproton collisions at sqrt{s}=1.8 TeV. This study tests a model of higher order QCD processes that result in gluon emission and can be used to estimate the magnitude of the contribution of processes higher than NLO. The total cross section is measured to be 466 +/- 3(stat.)^{+207}_{-70}(syst.) pb. The differential cross section is furthermore measured for all kinematically accessible regions of the Dalitz plane, including those for which the theoretical prediction is unreliable. While the measured cross section is consistent with the theoretical prediction in magnitude, the two differ somewhat in shape in the Dalitz plane.

hep-ex↗

arXiv1996

Anomalous Gauge Boson Couplings

The measurement of anomalous gauge boson self couplings is reviewed for a variety of present and planned accelerators. Sensitivities are compared for these accelerators using models based on the effective Lagrangian approach. The sensitivities described here are for measurement of generic parameters kappa_v, lambda_v, etc., defined in the text. Pre-LHC measurements will not probe these couplings to precision better than O(1/10). The LHC should be sensitive to better than O(1/100), while a future NLC should achieve sensitivity of O(1/1000) to O(1/10000) for center of mass energies ranging from 0.5 to 1.5 TeV.

hep-ph↗

arXiv1995

ANOMALOUS GAUGE BOSON INTERACTIONS

We discuss the direct measurement of the trilinear vector boson couplings in present and future collider experiments. The major goals of such experiments will be the confirmation of the Standard Model (SM) predictions and the search for signals of new physics. We review our current theoretical understanding of anomalous trilinear gauge boson self-interactions. If the energy scale of the new physics is $\sim 1$ TeV, these low energy anomalous couplings are expected to be no larger than ${\cal O}(10^{-2})$. Constraints from high precision measurements at LEP and low energy charged and neutral current processes are critically reviewed.

hep-ph↗

arXiv1994

Rapidity Correlations in $Wγ$ Production at Hadron Colliders

We study the correlation of photon and charged lepton pseudorapidities, $η(γ)$ and $η(\ell)$, $\ell=e,\,μ$, in $p\,\pbar \rightarrow W^\pmγ+X\rightarrow \ell^\pm p\llap/_Tγ+X$. In the Standard Model, the $Δη(γ,\ell)= η(γ) - η(\ell)$ differential cross section is found to exhibit a pronounced dip at $Δη(γ,\ell) \approx \mp 0.3$ ($=0$)in $p\bar p$ ($pp$) collisions, which originates from the radiation zero present in $q\bar q'\rightarrow Wγ$. The sensitivity of the $Δη(γ,\ell)$ distribution to higher order QCD corrections, non-standard $WWγ$ couplings, the $W+$~jet ``fake'' background and the cuts imposed is explored. At hadron supercolliders, next-to-leading order QCD corrections are found to considerably obscure the radiation zero. The advantages of the $Δη(γ,\ell)$ distribution over other quantities which are sensitive to the radiation zero are discussed. We conclude that photon lepton rapidity correlations at the Tevatron offer a {\it unique} opportunity to search for the Standard Model radiation zero in hadronic $Wγ$ production.

hep-ph↗

arXiv1993

Rapidity Correlations in $Wγ$ Production at the Tevatron

We study the correlation of photon and charged lepton pseudorapidities, $η(γ)$ and $η(\ell)$, $\ell=e,\,μ$, in $p\bar p\rightarrow W^\pmγ+X\rightarrow \ell^\pm p\llap/_Tγ+X$ at the Tevatron. In the Standard Model, the $Δη(γ,\ell)= η(γ) - η(\ell)$ differential cross section is found to exhibit a pronounced dip at $Δη(γ,\ell) \approx \mp 0.4$, which originates from the radiation zero present in $q\bar q'\rightarrow Wγ$. The sensitivity of the $Δη(γ,\ell)$ distribution to higher order QCD corrections, non-standard $WWγ$ couplings, and the cuts imposed is explored. The $Δη(γ,\ell)$ distribution is compared with other quantities which are sensitive to the radiation zero.

hep-ph↗

arXiv1993

Ratios of $W^\pmγ$ and $Zγ$ Cross Sections: New Tools in Probing the Weak Boson Sector at the Tevatron

The ratios ${\cal R}_{γ,\ell}=B(Z\to\ell^+\ell^-)\cdotσ(Zγ) /\allowbreak B(W\to\ellν)\cdotσ(W^\pmγ)$, ${\cal R}_{γ, ν}= B(Z\to\barνν)\cdotσ(Zγ)/\allowbreak B(W\to\ellν)\cdotσ(W^ \pmγ)$, ${\cal R}_{Wγ}=σ(W^\pmγ)/\allowbreakσ(W^\pm)$, and ${\cal R}_{Zγ}=σ(Zγ)/\allowbreakσ(Z)$ are studied as tools to probe the electroweak boson self-interactions. As a function of the minimum photon transverse momentum, ${\cal R}_{γ,\ell}$ and ${\cal R}_{ γ,ν}$ are found to directly reflect the radiation zero present in $W^ \pmγ$ production in the Standard Model. All four ratios are sensitive to anomalous $WWγ$ and/or $ZZγ/Zγγ$ couplings. The sensitivity of the cross section ratios to the cuts imposed on the final state particles, as well as the systematic uncertainties resulting from different parametrizations of parton distribution functions, the choice of the factorization scale $Q^2$, and from higher order QCD corrections are explored. Taking into account these uncertainties, sensitivity limits for anomalous three gauge boson couplings, based on a measurement of the cross section ratios with an integrated luminosity of 25~pb$^{-1}$ at the Tevatron, are estimated.

hep-ph↗