arXiv subjects

Dominic Hirschbuehl

Publications and source records attributed to Dominic Hirschbuehl.

5 recordsLinked to original sources

arXiv2026

Precise measurement of the $t\bar{t}$ production cross-section and lepton differential distributions in $e\mu$ dilepton events

Measurements of the inclusive and differential top-quark pair ($t\bar{t}$) cross-sections in proton--proton collisions at $\sqrt{s} = 13$ TeV, using 140 fb$^{-1}$ of data collected by the ATLAS experiment at the Large Hadron Collider, are presented. Events with an opposite-charge $e\mu$ pair and $b$-tagged jets are selected, and the inclusive cross-section measurement is used to determine the top-quark pole mass via the dependence of the predicted cross-section on $m_t^\mathrm{pole}$. Complementary measurements of $e\mu b\bar{b}$ production, treating both $t\bar{t}$ and $tW$ events as signal, are also provided.

hep-ex↗

arXiv2017

Single-top quark cross-section measurements in ATLAS

This article presents measurements of all three single top-quark production channels. Detailed measurements of $t$-channel single top-quark production using data collected by the ATLAS experiment in proton--proton collisions at a centre-of-mass energy of 8 TeV are shown as well es first results using 13 TeV at the LHC. The associated production of a top quark and a $W$ boson is presented for data collected at 13 TeV, while the first evidence of single top-quark production in the $s$-channel is shown for data collected at 8 TeV.

hep-ex↗

arXiv2014

Measurements of $t$-channel single top-quark production cross sections at $\sqrt{s} = 7$ TeV with the ATLAS detector

This article presents measurements of the $t$-channel single top-quark ($t$) and top-antiquark ($\bar{t}$) total production cross sections $σ(tq)$ and $σ(\bar{t}q)$, their ratio $R_t=σ(tq)/σ(\bar{t}q)$. Differential cross sections for the $σ(tq)$ and $σ(\bar{t}q)$ processes are measured as a function of the transverse momentum and the absolute value of the rapidity of ($t$) and ($\bar{t}$), respectively. The analysed data set was recorded with the ATLAS detector and corresponds to an integrated luminosity of 4.59 fb$^{-1}$. The cross sections are measured by performing a binned maximum-likelihood fit to the output distributions of neural networks. The resulting measurements are $σ(tq)=46 \pm 6$ pb, $σ(\bar{t}q)=23 \pm 4$ pb, $R_t=2.04 \pm 0.18$, consistent with the Standard Model expectation.

hep-ex↗

arXiv2007

Search for single top production using multivariate analyses at CDF

This article reports on recent searches for single-top-quark production by the CDF collaboration at the Tevatron using a data set that corresponds to an integrated luminosity of 955 fb^-1. Three different analyses techniques are employed, one using likelihood discriminants, one neural networks and one matrix elements. The sensitivity to single-top production at the rate predicted by the standard model ranges from 2.1 to 2.6 sigma. While the first two analyses observe a deficit of single-top like events compared to the expectation, the matrix element method observes an excess corresponding to a background fluctuation of 2.3 sigma. The null results of the likelihood and neural network analyses translate in upper limits on the cross section of 2.6 pb for the t-channel production mode and 3.7 pb for the s-channel mode at the 95% C.L. The matrix element result corresponds to a measurement of 2.7^{+1.5}_{-1.3} pb for the combined t- and s-channel single-top cross section. In addition, CDF has searched for non-standard model production of single-top-quarks via the s-channel exchange of a heavy W' boson. No signal of this process is found resulting in lower mass limits of 760 GeV/c^2 in case the mass of the right-handed neutrino is smaller than the mass of the right-handed W' or 790 GeV/c^2 in the opposite case.

hep-ex↗

arXiv2005

The PAX Toolkit and its Applications at Tevatron and LHC

At the CHEP03 conference we launched the Physics Analysis eXpert (PAX), a C++ toolkit released for the use in advanced high energy physics (HEP) analyses. This toolkit allows to define a level of abstraction beyond detector reconstruction by providing a general, persistent container model for HEP events. Physics objects such as particles, vertices and collisions can easily be stored, accessed and manipulated. Bookkeeping of relations between these objects (like decay trees, vertex and collision separation, etc.) including deep copies is fully provided by the relation management. Event container and associated objects represent a uniform interface for algorithms and facilitate the parallel development and evaluation of different physics interpretations of individual events. So-called analysis factories, which actively identify and distinguish different physics processes and study systematic uncertainties, can easily be realized with the PAX toolkit. PAX is officially released to experiments at Tevatron and LHC. Being explored by a growing user community, it is applied in a number of complex physics analyses, two of which are presented here. We report the successful application in studies of t-tbar production at the Tevatron and Higgs searches in the channel t-tbar-Higgs at the LHC and give a short outlook on further developments.

physics.data-an↗