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We address the coordination failures that arise in models with multiple equilibria and study how they may be resolved by reconsidering the role of cheap talk communication as an equilibrium selection device. We introduce an outside option (representing common-knowledge expected outcomes in the absence of coordination), and show that a player may be forced to make an announcement leading to a sub-optimal outcome with respect to the commitment solution (a binding message) in order to keep the message credible. The main contribution is to show, by means of examples taken from standard macro- and microeconomic decision making problems, how the existing tools of bargaining can be applied to models with multiple equilibria to produce sensible outcomes. The purpose is to provide a formal underpinning for methods that resolve multiple equilibrium problems by exploiting the power of policy announcements.

In the harsh environment of the Large Hadron Collider at CERN (design luminosity of 1034 cm-2s-1) efficient reconstruction of the signal primary vertex is crucial for many physics analyses. Described in this paper are primary vertex reconstruction strategies implemented in the ATLAS software framework Athena. The implementation of the algorithms follows a very modular design based on object oriented C++ and the use of abstract interfaces. This guarantees the easy use and exchange of different vertex fitters and finders which are considered for a given analysis. Such a modular approach relies on a dedicated Event Data Model for vertex reconstruction. The data model has been developed alongside the reconstruction algorithms. Its design is presented in detail. The performance of the implemented primary vertex reconstruction algorithms has been studied on a variety of Monte Carlo samples and results are presented.

Differences in preferences are important to explain variation in individuals' behavior. There is, however, no consensus on how to take these differences into account when evaluating policies. While prominent in the economic literature, the standard utilitarian criterion is controversial. According to some, interpersonal comparability of utilities involves value judgments with little objective basis. Others argue that social justice is primarily about the distribution of commodities assigned to individuals, rather than their subjective satisfaction or happiness. In this paper, we propose and axiomatically characterize a criterion, named opportunity-equivalent utilitarian, that addresses these claims. First, our criterion ranks social alternatives on the basis of individuals' ordinal preferences. Second, it compares individuals based on the fairness of their assignments. Opportunity-equivalent utilitarianism requires society to maximize the sum of specific indices of well-being that are cardinal, interpersonally comparable, and represent each individual's preferences.

The paper addresses intergenerational and intragenerational equity in an overlapping generation economy. We aim at defining an egalitarian distribution of a constant stream of resources, relying on ordinal non-comparable information on individual preferences. We establish the impossibility of efficiently distributing resources while treating equally agents with same preferences that belong to possibly different generations. We thus propose an egalitarian criterion based on the equal-split guarantee: this requires all agents to find their assigned consumption bundle at least as desirable as the equal division of resources.

(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) A search is presented for a high-mass Higgs boson in the ..., ..., ..., and ... decay modes using the ATLAS detector at the CERN Large Hadron Collider. The search uses proton-proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb... The results of the search are interpreted in the scenario of a heavy Higgs boson with a width that is small compared with the experimental mass resolution. The Higgs boson mass range considered extends up to ... for all four decay modes and down to as low as 140 ..., depending on the decay mode. No significant excess of events over the Standard Model prediction is found. A simultaneous fit to the four decay modes yields upper limits on the production cross-section of a heavy Higgs boson times the branching ratio to ... boson pairs. 95 % confidence level upper limits range from 0.53 pb at ... GeV to 0.008 pb at ... GeV for the gluon-fusion production mode and from 0.31 pb at ... GeV to 0.009 pb at ... GeV for the vector-boson-fusion production mode. The results are also interpreted in the context of Type-I and Type-II two-Higgs-doublet models.

A search is presented for the pair production of heavy vector-like B quarks, primarily targeting B quark decays into a W boson and a top quark. The search is based on 36.1 fb−1 of pp collisions at s=13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Data are analysed in the lepton-plus-jets final state, characterised by a high-transverse-momentum isolated electron or muon, large missing transverse momentum, and multiple jets, of which at least one is b-tagged. No significant deviation from the Standard Model expectation is observed. The 95% confidence level lower limit on the B mass is 1350 GeV assuming a 100% branching ratio to Wt. In the SU(2) singlet scenario, the lower mass limit is 1170 GeV. The 100% branching ratio limits are found to be also applicable to heavy vector-like X production, with charge +5/3, that decay into Wt. This search is also sensitive to a heavy vector-like B quark decaying into other final states (Zb and Hb) and thus mass limits on B production are set as a function of the decay branching ratios.

Cross-sections of associated production of a Higgs boson decaying into bottomquark pairs and an electroweak gauge boson, W or Z, decaying into leptons are measured as a function of the gauge boson transverse momentum. The measurements are performed in kinematic fiducial volumes defined in the ‘simplified template cross-section’ framework. The results are obtained using 79.8 fb−1 of proton-proton collisions recorded by the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. All measurements are found to be in agreement with the Standard Model predictions, and limits are set on the parameters of an effective Lagrangian sensitive to modifications of the Higgs boson couplings to the electroweak gauge bosons.

Higgs boson production cross-sections via gluon–gluon fusion and vector-boson fusion in proton–proton collisions are measured in the H → W W ∗ → ℓ ν ℓ ν decay channel. The Large Hadron Collider delivered proton–proton collisions at a centre-of-mass energy of 13 TeV between 2015 and 2018, which were recorded by the ATLAS detector, corresponding to an integrated luminosity of 140 fb - 1 . The total cross-sections for Higgs boson production by gluon–gluon fusion and vector-boson fusion times the H → W W ∗ branching ratio are measured to be 12 . 4 - 1.2 + 1.3 pb and 0 . 79 - 0.16 + 0.18 pb , respectively, in agreement with the Standard Model predictions. Higgs boson production is further characterised through measurements of Simplified Template Cross-Sections in a total of fifteen kinematic fiducial regions. A new scheme of kinematic fiducial regions has been introduced to enhance the sensitivity to CP-violating effects in Higgs boson interactions. Both schemes are used to constrain CP-even and CP-odd dimension-six operators in the Standard Model effective field theory

Measurements of t t ¯ ℓ + ℓ - production in the region of high dilepton invariant mass with effective field theory (EFT) interpretations are presented. They are performed using final states with three isolated leptons (electrons or muons) and are based on s = 13   Te V proton–proton collision data with an integrated luminosity of 140 fb - 1 , recorded from 2015 to 2018 with the ATLAS detector at the Large Hadron Collider. Measurements of the t t ¯ ℓ + ℓ - signal strength and cross-section upper-limits are performed inclusively in lepton flavour and separately for electrons and muons. The study also aims to probe anomalous four-fermion interactions including to test for possible lepton flavor universality violation. No significant deviations from the Standard Model predictions are observed and the measurements are interpreted through the EFT formalism to provide new constraints on the relevant operators.

A search for R-parity-conserving supersymmetry in events with large missing transverse momentum, jets and at least one hadronically decaying τ -lepton is presented. Both gluino and squark pair production are considered, with the cascade decay of each gluino or squark producing either a τ -slepton or a τ -sneutrino. Three channels are examined, requiring either exactly one hadronically decaying τ -lepton and no other leptons, exactly one hadronically decaying τ -lepton and at least one other lepton, or two or more hadronically decaying τ -leptons. Analyses in the three channels are optimised independently and combined statistically. Two separate analysis strategies, either a cut-and-count or machine-learning approach, are used. The search uses 140  fb - 1 and 51.8  fb - 1 of pp collision data recorded by the ATLAS detector at the Large Hadron Collider during 2015–2018 at s = 13  TeV and 2022–2023 at s = 13.6  TeV, respectively. Gluino masses below 2.25 TeV and squark masses up to 1.7 TeV are excluded