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Why should I comply with taxes if others don’t? Social information and behavioral convergence: An experimental study
No full textInternational audienceThis experimental study investigates the impact of social information about others’ tax behavior on individuals’subsequent tax decisions. Two types of social information are introduced: (i) the average income reportedwithin the subject’s entire group, and (ii) the average income reported within a reference subgroup made ofeither peers or non-peers and chosen by the subject. Our results show that social information significantlyaffects subsequent tax decisions, with a change in reported income ranging from 15% to 30% of total incomeon average. Moreover, the influence of whole-group information on tax behavior appears to be stronger thanthat of chosen-group information. Quite strikingly, a majority of subjects show more interest in the tax behaviorof non-peers than in that of peers. Finally, our data provide strong evidence of behavioral convergence towardsthe average tax behavior of others
Non-Asymptotic Convergence of Discrete Diffusion Models: Masked and Random Walk dynamics
No full textDiffusion models for continuous state spaces based on Gaussian noising processes are now relatively well understood, as many works have focused on their theoretical analysis. In contrast, results for diffusion models on discrete state spaces remain limited and pose significant challenges, particularly due to their combinatorial structure and their more recent introduction in generative modelling. In this work, we establish new and sharp convergence guarantees for three popular discrete diffusion models (DDMs). Two of these models are designed for finite state spaces and are based respectively on the random walk and the masking process. The third DDM we consider is defined on the countably infinite space and uses a drifted random walk as its forward process. For each of these models, the backward process can be characterized by a discrete score function that can, in principle, be estimated. However, even with perfect access to these scores, simulating the exact backward process is infeasible, and one must rely on approximations. In this work, we study Euler-type approximations and establish convergence bounds in both Kullback-Leibler divergence and total variation distance for the resulting models, under minimal assumptions on the data distribution. In particular, we show that the computational complexity of each method scales linearly in the dimension, up to logarithmic factors. Furthermore, to the best of our knowledge, this study provides the first non-asymptotic convergence guarantees for these noising processes that do not rely on boundedness assumptions on the estimated score
When Less is More: Approximating the Quantum Geometric Tensor with Block Structures
No full textThe natural gradient is central in neural quantum states optimizations but it is limited by the cost of computing and inverting the quantum geometric tensor, the quantum analogue of the Fisher information matrix. We introduce a block-diagonal quantum geometric tensor that partitions the metric by network layers, analogous to block-structured Fisher methods such as K-FAC. This layer-wise approximation preserves essential curvature while removing noisy cross-layer correlations, improving conditioning and scalability. Experiments on Heisenberg and frustrated - models show faster convergence, lower energy, and improved stability
A Year Under the DSA: Ad Transparency's Uneven Landscape
No full textInternational audienceThe Digital Services Act (DSA) has put platform accountability on center stage, requiring online platforms to provide greater transparency into how advertisements are targeted and delivered to users. Central to these obligations are two mechanisms: user-facing ad explanations, which inform individuals why they were shown a given ad, and public ad repositories, which are intended to enable independent auditing of advertising practices. This study provides the first multi-platform evaluation of these two mechanisms across Facebook, Instagram, YouTube and X. Using 48,511 user-facing "Why am I seeing this ad?" (WAIST) notices, and a systematic analysis of each platform's public ad repository, we assess how well current implementations disclose the parameters and decision processes involved in targeting. To do so, we develop and apply an operational framework based on Articles 26 and 39 of the DSA-capturing the granularity, attribution of targeting and delivery choices, data source disclosures, and accuracy-and apply it across both user-facing notices and public ad repositories. Our findings show that transparency remains fragmented and inconsistent across platforms. User-facing explanations vary widely in precision and often omit key targeting information, while repositories provide incomplete, misattributed, and at times difficult-to-interpret targeting data. Moreover, discrepancies between explanations and repository entries undermine the reliability of both mechanisms. Overall, current transparency infrastructures fall short of the DSA's expectations and highlight the need for clearer and more enforceable standards for advertising transparency moving forward.</div
First observation of the decay and evidence for the decay
No full textInternational audienceA search is presented for the two-body charmed baryonic decays , using a data sample collected by the LHCb experiment during 2011--2012 and 2015--2018 corresponding to an integrated luminosity of . The first observation of the decay is reported with significance, along with evidence for the decay. The branching fractions are measured to be and , where the first uncertainty is statistical, the second systematic, and the third due to external inputs. These results provide novel experimental inputs for the theoretical framework describing two-body baryonic decays of mesons via -emission and -exchange mechanisms
Performance of the front-end electronics of the CMS electromagnetic calorimeter barrel for the High-Luminosity LHC
No full textInternational audienceThe performance of the CMS electromagnetic calorimeter upgraded readout electronics, developed for the High-Luminosity phase of the LHC, is discussed. Data collected in two beam test campaigns conducted in 2018 and 2021 at the H4 and H2 beam lines of the CERN SPS are analyzed. Time and energy resolutions are measured on a matrix of lead tungstate crystals equipped with prototypes of the new front end readout electronics, using electron and pion beams of energies spanning from 25 to 250 GeV. In both campaigns the constant term of the energy resolution is measured to be better than 0.6% and the time resolution for electrons with energies above 50 GeV is measured to be better than 30 ps, fulfilling the design requirements
First Associated Neutrino Search for a Failed Supernova Candidate with Super-Kamiokande
No full textInternational audienceIn 2024, a failed supernova candidate, M31-2014-DS1, was reported in the Andromeda galaxy (M31), located at a distance of approximately 770 kpc. In this paper, we search for neutrinos from this failed supernova using data from Super-Kamiokande (SK). Based on the estimated time of black hole formation inferred from optical and infrared observations, we define a search window for neutrino events in the SK data. Using this window, we develop a dedicated analysis method for failed supernovae and apply it to M31-2014-DS1, by conducting a cluster search using the timing and energy information of candidate events. No significant neutrino excess is observed within the search region. Consequently, we place an upper limit on the electron antineutrino luminosity from M31-2014-DS1 and discuss its implications for various failed SN models and their neutrino emission characteristics. Despite the 18 MeV threshold adopted to suppress backgrounds, the search remains sufficiently sensitive to constrain the Shen-TM1 EOS, yielding a 90% confidence level upper limit of 1.76 \times 10^{53} erg on the electron antineutrino luminosity, slightly above the expected value of 1.35 \times 10^{53} erg
Observation of tWZ production at the CMS experiment
No full textInternational audienceThe first observation of single top quark production in association with a W and a Z boson in proton-proton collisions is reported. The analysis uses data at center-of-mass energies of 13 and 13.6 TeV recorded with the CMS detector at the CERN LHC, corresponding to a total integrated luminosity of 200 fb. Events with three or four charged leptons, which can be electrons or muons, are selected. Advanced machine-learning algorithms and improved reconstruction methods, compared to an earlier analysis, result in an unprecedented sensitivity to tWZ production. The measured cross sections for tWZ production are 248 52 fb and 244 74 fb for =13 and 13.6 TeV, respectively. The signal is established with a statistical significance of 5.8 standard deviations, with 3.5 expected, compared to the background-only hypothesis
Controlling the collective transport of large passive particles with suspensions of microorganisms
No full textInternational audienceA promising approach to transport cargo at the microscale lies within the use of self-propelled microorganisms, whose motion entrains that of passive particles. However, most applications remain limited to just a few passive particles of similar size as the microorganisms, since the transport mechanism relies on the interaction between individual swimmers and single particles. Here, we demonstrate how to control the collective transport of hundreds of large passive particles with phototactic microalga. Using directional light stimuli in suspensions of Chlamydomonas reinhardtii, we trigger bioconvection rolls capable of macroscale transport. Passive particles an order of magnitude larger than the microalgae are either attracted or repelled by the rolls depending on their density. Using experiments and simulation, we rationalize these bioconvective flows and describe how to harness them for cargo transport, with future applications in targeted drug delivery and decontamination
Model-independent measurement of the Higgs boson associated production with two jets and decaying to a pair of W bosons in proton-proton collisions at = 13 TeV
No full textInternational audienceA model-independent measurement of the differential production cross section of the Higgs boson decaying into a pair of W bosons, with a final state including two jets produced in association, is presented. In the analysis, events are selected in which the decay products of the two W bosons consist of an electron, a muon, and missing transverse momentum. The model independence of the measurement is maximized by making use of a discriminating variable that is agnostic to the signal hypothesis developed through machine learning. The analysis is based on proton-proton collision data at = 13 TeV collected with the CMS detector from 20122018, corresponding to an integrated luminosity of 138 fb. The production cross section is measured as a function of the difference in azimuthal angle between the two jets. The differential cross section measurements are used to constrain Higgs boson couplings within the standard model effective field theory framework