Publications database

A precision luminosity measurement is essential for LHC cross-section measurements to determine fundamental parameters of the standard model and constrain or discover beyond-the-standard-model phenomena. The luminosity of the CMS detector has been measured at the LHC Interaction Point~5 using proton-proton collisions at $\sqrt{s}=13$ TeV during the Run 2 data-taking period (2015-2018). [...]

In high-energy particle physics, complex Monte Carlo (MC) simulations are needed to compare theory predictions to measurable quantities. Many and large MC samples are needed to be generated to take into account all the systematics. [...]

A search for central exclusive production of top quark pairs ($\mathrm{t}\bar{\mathrm{t}}$) is presented using collision data collected by CMS and the CMS-TOTEM Precision Proton Spectrometer in 2017. A data-driven method to estimate the background from coincidences of inclusive events and pileup protons is described, as well as the development of a Boosted Decision Tree classifier to separate the exclusive $\mathrm{t}\bar{\mathrm{t}}$ signal from the inclusive $\mathrm{t}\bar{\mathrm{t}}$ background. [...]

The electroweak mixing angle is a fundamental parameter of the theory of electroweak interactions. Its value has been measured precisely at the $\mathrm{Z}$-pole at colliders. [...]

Single-differential cross section predictions for top quark pair production are presented at next-to-leading order, using running top quark mass renormalization schemes. The evolution of the mass of the top quark is performed in the MSR scheme $m_\mathrm{t}^{\textrm{MSR}}(\mu)$ for renormalization scales $\mu$ below the $\overline{\textrm{MS}}$ top quark mass $\overline{m}_\mathrm{t}(\overline{m}_\mathrm{t})$, and in the $\overline{\textrm{MS}}$ scheme $\overline{m}_\mathrm{t}(\mu)$ for scales above. [...]

In the TESLA Test Facility, wire scanners are used to measure the electron beam profile and position. The intended use of the wire scanners (to center the electron beam in the Free Electron Laser undulator) requires an especially precise alignment of the wire scanners with respect to the undulator axis. [...]

In these proceedings, a measurement of the differential cross section of top quark-antiquark pair ($\text{t}\overline{\text{t}}$) production in association with one additional jet ($\text{t}\overline{\text{t}}$+jet) as a function of the inverse of the invariant mass of the $\text{t}\overline{\text{t}}$+jet system, $\rho=340\,\text{GeV}/m_{\text{t}\overline{\text{t}}+\text{jet}}$, is presented. The normalized $\text{t}\overline{\text{t}}$+jet cross section is used to extract values for the top quark pole mass $m_{\text{t}}^{\text{pole}}$ by a comparison to theoretical predictions at next-to-leading order accuracy. [...]

It has been repeatedly observed, at TTF-FEL, that the energy profile of the fully longitudinally compressed beam breaks up into peaks. In this paper we analyze a potential cause of this effect. [...]

A single-pass free-electron laser operating in the self-amplified spontaneous-emission (SASE) mode at around 100 nm is currently under test at the TESLA Test Facility at DESY. After first observation of SASE in February 2000, the photon beam has been characterized by different techniques. [...]

The strategies for and the performance of the CMS tracker alignment during the 2021-2022 LHC commissioning preceding the Run 3 data-taking period are described. The results of the very first tracker alignment after the pixel reinstallation, performed with cosmic ray muons recorded with the solenoid magnet off are presented. [...]