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Reinhard Schwienhorst

Publications and source records attributed to Reinhard Schwienhorst.

29 records · Page 2Linked to original sources
arXiv2010

Single top quark production and decay in the t-channel at next-to-leading order at the LHC

We present a study of single top and single antitop quark production in the t-channel mode at the LHC pp collider at 7 TeV, 10 TeV and 14 TeV, including next-to-leading order QCD corrections to the production and decay of the top quark. We discuss the effects of different O(alpha_s) contributions on the inclusive cross section and important kinematic distributions, after imposing the relevant cuts to select t-channel single top quark events.

hep-ph↗
arXiv2010

Single top quark production and Vtb at the Tevatron

Single top quark production via the electroweak interaction was observed by the D0 and CDF collaborations at the Tevatron proton-antiproton collider at Fermilab. Multivariate analysis techniques are employed to extract the small single top quark signal. The combined Tevatron cross section is 2.76^+0.58_-0.47 pb. This corresponds to a lower limit on the CKM matrix element |Vtb| of 0.77. Also reported are measurements of the t-channel cross section, the top quark polarization in single top quark events, and limits on gluon-quark flavor-changing neutral currents and W' boson production.

hep-ex↗
arXiv2010

Next-to-leading order QCD corrections to s-channel single top quark production and decay at the LHC

We present a study of electroweak production of top and antitop quarks in the s-channel mode at the LHC, including next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to the production and decay of the single (anti)top quark. The spin is preserved in production and decay by using the narrow width approximation for the (anti)top quark. We show the effect of different O(alpha_s) contributions on the inclusive cross section and various kinematic distributions at parton level after imposing relevant kinematic cuts to select s-channel single top quark events. We also discuss several possibilities for measuring the top quark polarization.

hep-ph↗
arXiv2009

Observation of Single Top Quark Production with the D0 Detector

We report on the observation of single top quark production by the D0 collaboration using a dataset of 2.3 fb^-1 collected at the Fermilab Tevatron ppbar collider. Several multivariate techniques are combined to separate the single top signal from backgrounds. The measured single top cross section is 3.94+-0.88pb. The probability to measure a cross section at this value or higher in the absence of signal is 2.9*10^-7, corresponding to a 5.0 standard deviation significance for the presence of signal. The lower limit at the 95% C.L. on the CKM matrix element Vtb is |Vtb|>0.78. A separate measurement of the t-channel cross section gives 3.14 +0.94 -0.80 pb.

hep-ex↗
arXiv2008

Single top quark production at the Tevatron

The Tevatron experiments D0 and CDF have found evidence for single top quark production, based on datasets between 0.9fb-1 and 2.2fb^-1. Several different multivariate techniques are used to extract the single top quark signal out of the large backgrounds. The cross section measurements are also used to provide the first direct measurement of the CKM matrix element |Vtb|.

hep-ex↗
arXiv2007

Colliding neutrino beams

From several neutrino oscillation experiments, we understand now that neutrinos have mass. However, we really don't know what mechanism is responsible for producing this neutrino mass. Current or planned neutrino experiments utilize neutrino beams and long-baseline detectors to explore flavor mixing but do not address the question of the origin of neutrino mass. In order to answer that question, neutrino interactions need to be explored at much higher energies. This paper outlines a program to explore neutrinos and their interactions with various particles through a series of experiments involving colliding neutrino beams.

hep-ex↗
arXiv2005

Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 2. $t$-channel Process

We present a study of the $t$-channel mode of single top quark production at the upgraded Tevatron $p\bar{p}$ collider, including the next-to-leading order (NLO) QCD corrections to the production and the decay of a single top quark. The narrow width approximation was adopted in order to preserve the spin of the top quark in its production and decay. We discuss the effects of different $O(α_s)$ contributions on the inclusive cross section as well as various kinematic distributions after imposing the relevant cuts to select $t$-channel single top signal events.

hep-ph↗
arXiv2005

Next-to-Leading Order Corrections to Single Top Quark Production and Decay at the Tevatron: 1. s-channel Process

We present a study of s-channel single top quark production at the upgraded Tevatron $p\bar{p}$ collider, including the next-to-leading order (NLO) QCD corrections to the production and the decay of the top quark. The "modified" narrow width approximation was adopted to preserve the spin of the top quark in its production and decay. We discuss the effect of the different $O(α_s)$ contributions on the inclusive cross section as well as various kinematic distributions after imposing the relevant cuts to select s-channel single top signal events. In particular the $O(α_s)$ decay contribution, while small in size, has a significant impact on several distributions. With the help of the best-jet algorithm to reconstruct the top quark we demonstrate that it is possible to study kinematical and spin correlations in s-channel single top events. We furthermore compare top quark spin measurements in two different basis and show how NLO corrections have to be taken into consideration in searches for the Higgs boson through $W^{\pm}H$ associated production at the Tevatron.

hep-ph↗
arXiv2004

Top Quark Production Cross Section at E^cm=1.96TeV

Preliminary results on the top pair production cross section measurements by the D0 and CDF experiments in Run II at the Tevatron are presented. The measurements are obtained using various final state signatures.

hep-ex↗
arXiv2004

Search for Single Top Production at the Tevatron

Searches for the electroweak production of single top quarks have been started at the Fermilab Tevatron proton-antiproton collider using Run II data by both the D0 and CDF collaborations. Using a dataset of approximately 160pb^-1, neither experiment finds evidence for Single Top production and sets 95% C.L. upper limits on the production cross section. The D0 limits are 19pb on the s-channel production, 25pb on the t-channel production, and 23pb on the combined s+t-channel production. The CDF limits are 8.5pb on the t-channel production and 13.7pb on the combined s+t-channel production.

hep-ex↗