Adversarial domain adaptation to reduce sample bias of a high energy physics classifier

We apply adversarial domain adaptation to reduce sample bias in a classification machine learning algorithm. We add a gradient reversal layer to a neural network to simultaneously classify signal versus background events, while minimising the difference of the classifier response to a background sample using an alternative MC model. We show this on the example of simulated events at the LHC with $t\bar{t}H$ signal versus $t\bar{t}b\bar{b}$ background classification.Comment: 15 pages, 8 figures, to be submitted to JINS

Handling the hype: Implications of AI hype for public interest tech projects

Based on theories of expectations of technology and empirical data from expert interviews and case studies, this research article explores how actors in the field of public interest technologies relate to and within the dynamics of AI hype. On an affirmative note, practitioners and experts see the potential that AI hype can serve their own purposes, e.g., through improved funding and support structures. At the same time, public interest tech actors distance themselves from the dynamics of AI hype and criticize it explicitly. Finally, the article discusses how engagement with AI hype and its impact affects society as a whole and, more specifically, society's ability to develop and use technologies in response to societal problems.Auf der Grundlage von Theorien über Erwartungen an Technologien und anhand empirischer Daten aus Expert*inneninterviews und Fallstudien untersucht dieser Forschungsartikel, wie sich Akteur*innen im Bereich der Public-Interest-Technologien im und zum KI-Hype verhalten. Praktiker*innen und Expert*innen sehen einerseits, dass der KI-Hype ihren eigenen Interessen dienen kann, z.B. durch verbesserte Finanzierungs- und Förderstrukturen. Gleichzeitig distanzieren sich Public-Interest-Tech-Akteur*innen von der Dynamik des KI-Hypes und kritisieren ihn ausdrücklich. Abschließend wird im Artikel diskutiert, wie sich die Auseinandersetzung mit dem KI-Hype und dessen Wirkung auf die Gesellschaft insgesamt auswirkt und speziell auf die Fähigkeit der Gesellschaft, Technologien zur Lösung gesellschaftlicher Probleme zu entwickeln und einzusetzen

Constraining the CP structure of Higgs-fermion couplings with a global LHC fit, the electron EDM and baryogenesis

CP violation in the Higgs couplings to fermions is an intriguing, but not yet extensively explored possibility. We use inclusive and differential LHC Higgs boson measurements to fit the CP structure of the Higgs Yukawa couplings. Starting with simple effective models featuring CP violation in a single Higgs–fermion coupling, we probe well-motivated models with up to nine free parameters. We also investigate the complementarity of LHC constraints with the electron electric dipole moment bound, taking into account the possibility of a modified electron Yukawa coupling, and assess to which extent CP violation in the Higgs–fermion couplings can contribute to the observed baryon asymmetry of the universe. Even after including the recent analysis of angular correlations in H→ τ+τ- decays, we find that a complex tau Yukawa coupling alone may be able to account for the observed baryon asymmetry, but with large uncertainties in the baryogenesis calculation. A combination of complex top and bottom quark Yukawa couplings yields a result four times larger than the sum of their separate contributions, but remains insufficient to account for the observed baryon asymmetry. © 2022, The Author(s)

Indirect CP\mathcal{CP} probes of the Higgs-top-quark interaction: current LHC constraints and future opportunities

The $\mathcal{CP}$ structure of the Higgs boson in its coupling to the particles of the Standard Model is amongst the most important Higgs boson properties which have not yet been constrained with high precision. In this study, all relevant inclusive and differential Higgs boson measurements from the ATLAS and CMS experiments are used to constrain the $\mathcal{CP}$-nature of the top-Yukawa interaction. The model dependence of the constraints is studied by successively allowing for new physics contributions to the couplings of the Higgs boson to massive vector bosons, to photons, and to gluons. In the most general case, we find that the current data still permits a significant $\mathcal{CP}$-odd component in the top-Yukawa coupling. Furthermore, we explore the prospects to further constrain the $\mathcal{CP}$ properties of this coupling with future LHC data by determining $tH$ production rates independently from possible accompanying variations of the $t\bar t H$ rate. This is achieved via a careful selection of discriminating observables. At the HL-LHC, we find that evidence for $tH$ production at the Standard Model rate can be achieved in the Higgs to diphoton decay channel alone.Comment: 55 pages, 21 figures, 6 tables; v4: resubmission to JHE

Measurement of Mutual Coulomb Dissociation in sNN=130\sqrt{s_{NN}}=130 GeV Au+Au collisions at RHIC

We report on the first measurement of Mutual Coulomb Dissociation in heavy ion collisions. We employ forward calorimeters to measure neutron multiplicity at beam rapidity in peripheral collisions. The cross-section for simultaneous electromagnetic breakup of Au nuclei at $\sqrt{s_{NN}}=130$ GeV is $\sigma_{MCD}=3.67\pm 0.25$ barns in good agreement with calculations.Comment: This paper has been submitted for publication in Phys. Rev. Let

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements