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1. Dijet spectrum in nonlocal and asymptotically nonlocal theories

   https://doi.org/10.1103/PhysRevD.110.055018  

   Anderson, Mikkie R; Carone, Christopher D (September 2024, Physical Review D)

   Asymptotically nonlocal field theories approximate ghost-free nonlocal theories at low energies, yet are theories of finite order in the number of derivatives. These theories have an emergent nonlocal scale that regulates loop diagrams and can provide a solution to the hierarchy problem. Asymptotic nonlocality has been studied previously in scalar theories, Abelian and non-Abelian gauge theories with complex scalars, and linearized gravity. Here we extend that work by considering an asymptotically nonlocal generalization of QCD, which can be used for realistic phenomenological investigations. In particular, we derive Feynman rules relevant for the study of the production of dijets at hadron colliders and compute the parton-level cross sections at leading order. We use these to determine a bound on the scale of new physics from Large Hadron Collider data, both for a typical choice of model parameters, and in the nonlocal limit. 

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2. Some simple theories from a Boolean algebra point of view

   https://doi.org/10.1016/j.apal.2023.103345  

   Malliaris, M; Shelah, S (January 2024, Annals of Pure and Applied Logic)

   We find a strong separation between two natural families of simple rank one theories in Keisler's order: the theories $$T_m$$ reflecting graph sequences, which witness that Keisler's order has the maximum number of classes, and the theories $$T_{n,k}$$, which are the higher-order analogues of the triangle-free random graph. The proof involves building Boolean algebras and ultrafilters ``by hand'' to satisfy certain model theoretically meaningful chain conditions. This may be seen as advancing a line of work going back through Kunen's construction of good ultrafilters in ZFC using families of independent functions. We conclude with a theorem on flexible ultrafilters, and open questions. 

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3. Higher-spin localized shocks

   https://doi.org/10.1103/fpbn-pkyh  

   Wang, Diandian; Wang, Zi-Yue (September 2025, Physical Review D)

   In the context of anti-de Sitter/conformal field theory , gravitational shockwaves serve as a geometric manifestation of boundary quantum chaos. We study this connection in general diffeomorphism-invariant theories involving an arbitrary number of bosonic fields. Specifically, we demonstrate that theories containing spin-2 or higher-spin fields generally admit classical localized shockwave solutions on black hole backgrounds, whereas spin-0 and spin-1 theories do not. As in the gravitational case, these higher-spin shockwaves provide a means to compute the out-of-time-order correlator. Both the Lyapunov exponent and the butterfly velocity are found to universally agree with predictions from pole skipping. In particular, higher-spin fields lead to a Lyapunov exponent that violates the chaos bound and a butterfly velocity that may exceed the speed of light. 

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4. VOAs and Rank-Two Instanton SCFTs

   https://doi.org/10.1007/s00220-020-03746-9  

   Beem, Christopher; Meneghelli, Carlo; Peelaers, Wolfger; Rastelli, Leonardo (March 2020, Communications in Mathematical Physics)

   We analyze the N = 2 superconformal field theories that arise when a pair of D3-branes probe an F-theory singularity from the perspective of the associated vertex operator algebra. We identify these vertex operator algebras for all cases; we find that they have a completely uniform description, parameterized by the dual Coxeter number of the corresponding global symmetry group. We further present free field realizations for these algebras in the style of recent work by three of the authors. These realizations transparently reflect the algebraic structure of the Higgs branches of these theories. We find fourth-order linear modular differential equations for the vacuum characters/Schur indices of these theories, which are again uniform across the full family of theories and parameterized by the dual Coxeter number.We comment briefly on expectations for the still higher-rank cases. 

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5. New anomaly free supergravities in six dimensions

   https://doi.org/10.1007/JHEP05(2024)144  

   Becker, K; Kehagias, A; Sezgin, E; Tennyson, D; Violaris, A (May 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> An extended search for anomaly free matter coupledN= (1,0) supergravity in six dimension is carried out by two different methods which we refer to as the graphical and rank methods. In the graphical method the anomaly free models are built from single gauge group models, called nodes, which can only have gravitational anomalies. We search for anomaly free theories with gauge groupsG₁× … ×G_nwithn= 1,2,… (any number of factors) andG₁× … ×G_n×U(1)_Rwheren= 1,2,3 andU(1)_Ris theR-symmetry group. While we primarily consider models with the tensor multiplet numbern_T= 1, we also provide some results forn_T≠ 1 with an unconstrained number of charged hypermultiplets. We find a large number of ungauged anomaly free theories. However, in the case ofR-symmetry gauged models withn_T= 1, in addition to the three known anomaly free theories withG₁×G₂×U(1)_Rtype symmetry, we find only six new remarkably anomaly free models with symmetry groups of the formG₁×G₂×G₃×U(1)_R. In the case ofn_T= 1 and ungauged models, excluding low rank group factors and considering only low lying representations, we find all anomaly free theories. Remarkably, the number of group factors does not exceed four in this class. The proof of completeness in this case relies on a bound which we establish for a parameter characterizing the difference between the number of non-singlet hypermultiplets and the dimension of the gauge group. 

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