Systematic study of niobium thermal treatments for superconducting radio frequency cavities employing x-ray photoelectron spectroscopy

SUPERCONDUCTOR SCIENCE & TECHNOLOGY 35:6 (2022) ARTN 065019

Authors:

A Prudnikava, Y Tamashevich, S Babenkov, A Makarova, D Smirnov, V Aristov, O Molodtsova, O Kugeler, J Viefhaus, B Foster

High-precision measurement of the W boson mass with the CDF II detector

Science American Association for the Advancement of Science 376:6589 (2022) 170-176

Authors:

T Aaltonen, S Amerio, D Amidei, A Anastassov, A Annovi, G Apollinari, Ja Appel, T Arisawa, A Artikov, W Ashmanskas, B Auerbach, A Boveia, Hs Budd, K Burkett, G Busetto, P Butti, A Buzatu, A Calamba, S Camarda, C Hays

Abstract:

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, MW, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

Radiation hardness and timing performance in MALTA monolithic pixel sensors in TowerJazz 180 nm

JOURNAL OF INSTRUMENTATION 17:4 (2022) ARTN C04034

Authors:

M van Rijnbach, P Allport, I Asensi, I Berdalovic, D Bortoletto, C Buttar, R Cardella, F Dachs, V Dao, H Denizli, D Dobrijevic, M Dyndal, L Flores, P Freeman, A Gabrielli, L Gonella, M LeBlanc, K Oyulmaz, H Pernegger, F Piro, P Riedler, H Sandaker, C Solans, W Snoeys, T Suligoj, J Torres, S Worm

Impact of jet-production data on the next-to-next-to-leading-order determination of HERAPDF2.0 parton distributions

European Physical Journal C: Particles and Fields Springer Nature 82:3 (2022) 243

Authors:

I Abt, R Aggarwal, V Andreev, Amanda Cooper-Sarkar, Brian Foster, Claire Gwenlan, Voica Radescu

Abstract:

The HERAPDF2.0 ensemble of parton distribution functions (PDFs) was introduced in 2015. The final stage is presented, a next-to-next-to-leading-order (NNLO) analysis of the HERA data on inclusive deep inelastic ep scattering together with jet data as published by the H1 and ZEUS collaborations. A perturbative QCD fit, simultaneously of αs(M2Z) and the PDFs, was performed with the result αs(M2Z)=0.1156±0.0011 (exp) +0.0001−0.0002 (model +parameterisation) ±0.0029 (scale). The PDF sets of HERAPDF2.0Jets NNLO were determined with separate fits using two fixed values of αs(M2Z), αs(M2Z)=0.1155 and 0.118, since the latter value was already chosen for the published HERAPDF2.0 NNLO analysis based on HERA inclusive DIS data only. The different sets of PDFs are presented, evaluated and compared. The consistency of the PDFs determined with and without the jet data demonstrates the consistency of HERA inclusive and jet-production cross-section data. The inclusion of the jet data reduced the uncertainty on the gluon PDF. Predictions based on the PDFs of HERAPDF2.0Jets NNLO give an excellent description of the jet-production data used as input.

Operation and performance of the ATLAS semiconductor tracker in LHC Run 2

Journal of Instrumentation IOP Publishing 17:01 (2022) P01013

Authors:

Brad Abbott, L Ambroz, G Artoni, WK Balunas, YT Harris, CP Hays, K Karava, Z Li, C Merlassino, M Mironova, RB Nickerson, AP O’Neill, SR Paredes Saenz, CS Pollard, E Schopf, IPJ Shipsey, HA Smith, M Stankaityte, I Veliscek, GHA Viehhauser, AR Weidberg, PJ Windischhofer, R Wölker, KW Woźniak, K Potamianos

Abstract:

The semiconductor tracker (SCT) is one of the tracking systems for charged particles in the ATLAS detector. It consists of 4088 silicon strip sensor modules. During Run 2 (2015–2018) the Large Hadron Collider delivered an integrated luminosity of 156 fb-1 to the ATLAS experiment at a centre-of-mass proton-proton collision energy of 13 TeV. The instantaneous luminosity and pile-up conditions were far in excess of those assumed in the original design of the SCT detector. Due to improvements to the data acquisition system, the SCT operated stably throughout Run 2. It was available for 99.9% of the integrated luminosity and achieved a data-quality efficiency of 99.85%. Detailed studies have been made of the leakage current in SCT modules and the evolution of the full depletion voltage, which are used to study the impact of radiation damage to the modules.