Valerie Scheurer

A bstract A search for new top quark interactions is performed within the framework of an effective field theory using the associated production of either one or two top quarks with a Z boson in multilepton final states. The data sample corresponds to an integrated luminosity of 138 fb − 1 of proton-proton collisions at $$ \sqrt{s} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> </mml:math> = 13 TeV collected by the CMS experiment at the LHC. Five dimension-six operators modifying the electroweak interactions of the top quark are considered. Novel machine-learning techniques are used to enhance the sensitivity to effects arising from these operators. Distributions used for the signal extraction are parameterized in terms of Wilson coefficients describing the interaction strengths of the operators. All five Wilson coefficients are simultaneously fit to data and 95% confidence level intervals are computed. All results are consistent with the SM expectations.

The Pixel Luminosity Telescope is a silicon pixel detector dedicated to luminosity measurement at the CMS experiment at the LHC. It is located approximately 1.75 m from the interaction point and arranged into 16 "telescopes", with eight telescopes installed around the beam pipe at either end of the detector and each telescope composed of three individual silicon sensor planes. The per-bunch instantaneous luminosity is measured by counting events where all three planes in the telescope register a hit, using a special readout at the full LHC bunch-crossing rate of 40 MHz. The full pixel information is read out at a lower rate and can be used to determine calibrations, corrections, and systematic uncertainties for the online and offline measurements. This paper details the commissioning, operational history, and performance of the detector during Run 2 (2015-18) of the LHC, as well as preparations for Run 3, which will begin in 2022.

14-fs pulses at 1.3μm were generated by an all-solid-state, Kerr-lens mode-locked Crforsterite laser using double chirped mirrors. The spectral bandwidth (FWHM) was 250 mm with an 80 mW average power and 100 MHz repetition rate.

14-fs pulses at 1.3 µm were generated by an all-solid-state, Kerr-lens mode-locked Cr:forsterite laser using double-chirped mirrors. The spectral bandwidth (FWHM) was 250 nm with an 80 mW average power and 100 MHz repetition rate.

19-fs pulses were generated by an all-solid-state, Kerr-lens mode-locked Criforsterite laser using double chirped mirrors for dispersion control. The laser spectrum extended from 12501500 nm at 80 mW average power and 100 MHz repetition rate.