Our group has of course plenty of amazing results and publications, and it would be too difficult to keep our home page up to date when we have to write about every single publication that we produce. Most of our works, which have not been conducted within our scientific collaborations, can be easily found on inspires. Below you find selected publications, which we find truly outstanding and are the result of many brilliant people of our group. In particular, we summarise those, which are directly related to our main research goals.
First Measurement of the W Boson Width at the LHC
March 2024: We finally managed to published the first (and best) measurement of the W boson width and - maybe even more importantly - also an improved measurement of the W boson mass using for the first time a profile likelihood technique for this measurement. We believe that this measurement approach is paving the ground for all the following measurements also by other experiments and really opens the door to a new round of precision measurements.
We started this work with the PhD thesis of Andreas Düdder, continued it with the PhD thesis of Adam Lennard and the Humboldt fellowship of Dr. Jakub Kremer, finally concluded on the results with the Andres Eloy Pinto Pinoargote and Dr. Chen Wang - in addition obviously with our collaboration partners in Paris, Belgrade and Bonn.
Read more: ATLAS Collaboration, Measurement of the W-boson mass and width with the ATLAS detector using proton-proton collisions at 7 TeV, e-Print: 2403.15085
First Search for Long Lived Axion-Like Particles at FASER
April 2024: Dr. Jack MacDonald, Dr. Friedemann Neuhaus and Eunhyung Cho have been working on the first search for axion-like particles produced in proton-proton collisions at the LHC together with our colleagues from the FASER experiment. Our group was involved in FASER since its beginning, contributing to the detector construction and calibration in the context of the ERC Light@LHC Grant. Unfortunately, we did not (yet) find evidence for the existence of ALPs, however, we just started searching.
Read more: FASER Collaboration, Search for Axion-like Particles in Photonic Final States with the FASER Detector at the LHC, CERN-FASER-CONF-2024-001, https://cds.cern.ch/record/2892328
First Search for Long Lived Axion-Like Particles at the LHC
December 2023: There was one last (sensible) model remaining that could explain the muonic (g-2) discrepancy between theory and experiment, which predicts axion-like particles with significant lifetimes that also couple to the Higgs boson. Since 2020, we (Dr. Kristof Schmieden, Olivera Vujinovic, Friedemann Neuhaus, Peter Krämer, Dr. Bernhard Brickwedde) have been developing within the ERC Light@LHC project dedicated reconstruction methods for displaced photon signatures at the ATLAS experiment, that could probe exactly this model. Our analysis used the full run-2 data-set of the LHC and could rule out large parts of the remaining phase space, thus implying that the muonic (g-2) discrepancy might be simply due to a misunderstanding in the underlying theory of its prediction.
Read more: ATLAS Collaboration, Search for short- and long-lived axion-like particles in H→aa→4γH→aa→4γdecays with the ATLAS experiment at the LHC, e-Print: 2312.03306
Most Precise Experimental Measurement of the Strong Coupling Constant
Mai 2022: The idea to use the Z boson transverse momentum spectrum came up already during the PhD thesis of Jakub Cuth. At this point, the theoretical uncertainties were still huge, however, it was also clear how this could be improved. Due to the outstanding work of Stefano Camarda, we could finally make this approach work, resulting in the most precise experimental determination of the strong coupling constant, reinterpreting public data from the CDF experiment. This result opens up a completely new approach to measure the strong coupling constant and was directly adopted by the ATLAS Collaboration for an even more precise measurement.
Read more: S. Camarda, G. Ferrera, M. Schott, Determination of the strong-coupling constant from the Z-boson transverse-momentum distribution, Eur.Phys.J.C 84 (2024) 1, 39, e-Print: 2203.05394
First Measurement of the W Boson Mass at the LHC
November 2017: Finally, after six years of work, we managed to publish the first measurement of the W boson mass at the LHC, already being the single most precise measurement world wide. This publication is based on the work for so many people of my group (Jakub Cuth and Christoph Zimmermann as PhD students, Dr. Mikhail Karnevski and Dr. Samuel Webb as Postdocs) and our colleagues mainly at CEA Saclay (to mention in particular Maarten Boonekamp, Nandi Andari, Nenad Vranjes and Aleksandra Dimitrievska) and I am grateful to have worked together with such an amazing team over such along time. I am also very grateful for the long term support of the DFG Emmy Noether Group program as well as the Lichtenberg funding of the Volkswagen foundation, who actually allowed me to work on this for such a long time. Looking at our results, it seems, that the world is indeed not supersymmetric. Before I forget: One word to the referee, who explicitly said that he would not fund this project, because it is impossible to do - well, actually no word is needed.
Read more: ATLAS Collaboration, Measurement of the 𝑊-boson mass in 𝑝𝑝 collisionsat 7TeV with the ATLASdetector, Eur. Phys. J. C 78 (2018) 110, arXiv:1701.07240
First Evidence of Light-by-Light Scattering
February 2017: Heisenberg and his student Euler predicted the scattering of light in the context of quantum theories already in the 1930s. However, I realized only in 2015 when reading a great paper by David d'Enterria and Gustavo G. da Silveira that one can observe this process for the first time at the LHC using ultraperipheral heavy ion collisions. Luckily I could convince my friends in the ATLAS collaboration to act quickly and setup the corresponding trigger for such a process in time. What followed was a extremely quick data analysis together with Alexander Sydorenko and Samuel Webb together with our colleagues mainly in Cracow resulting in the first evidence for light-by-light scattering, as predicted so many decades ago. Clearly, the full observation and the reinterpretation in the context of axion-like particles followed soon after.
Read more: ATLAS Collaboration: Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC, Published in: Nature Phys. 13 (2017) 9, 852-858, e-Print: 1702.01625
Design and Construction of the First Prototype Detector for the ATLAS New Small Wheel Upgrade Project
Nov. 2015: Unfortunately, progress in experimental particle physics is mainly measured by new insights in the fundamental aspects of the universe via new measurements and searches. However, we couldn't do that without great detectors. We are extremely proud to have constructed a first working prototype detector for the upgrade program of the ATLAS muon system together with our collaboration particles at CERN. This prototype detector build the basis for a world-wide construction effort for a completely new sub-detector system of ATLAS, worth millions of dollars and a unique physics performance. You can see on the picture Andreas Düdder and Tai-Hua Lin, who install our prototype detector at ATLAS for first test measurements in real conditions.
Read more: Construction of two large-size four-plane micromegas detectors, Published in: Nucl.Instrum.Meth.A 814 (2016) 117-130, e-Print: 1511.03884
Most stringent Model-Independent Limits on Axion-Like Particles
June 2015: After four years of preparation, we finally were taking data at the OSQAR Experiment, resulting in the most stringent model-independent limits on axion-like particles. OSQAR is a very small collaboration, so all aspects of the experiment are actually handled by everybody. In fact, we have been spending countless evenings to align the two LHC magnets, setup to camera and the laser, that it was in the end a huge excitement, when the first results come out using a completely new analysis technique developed by Christoph Weinsheimer in his PhD thesis.
Read more: OSQAR Collaboration: New exclusion limits on scalar and pseudoscalar axionlike particles from light shining through a wall, Published in: Phys.Rev.D 92 (2015) 9, 092002, e-Print: 1506.08082
On the impact of the Higgs Boson Discovery on the Status of the Global Electroweak Fit
September 2012: The idea of the global electroweak fit is nearly as old as the Standard Model itself. I was lucky to be part of the Gfitter collaboration during the discovery of the Higgs Boson, as we reanalysed all available data including the Higgs boson mass for the first time. Many plots of this publications made it to text books afterwards. In fact, those studies have been my main motivation to spent a significant part of my scientific life on the W boson mass measurement.
Read more: Gfitter Group, The Electroweak Fit of the Standard Model after the Discovery of a New Boson at the LHC
Published in: Eur.Phys.J.C 72 (2012) 2205, e-Print: 1209.2716
