Ling-Xiao Xu - Spurion Analysis for a Class of Selection Rules Without Group Actions @IhesFr

Uploaded March 2026 | Updated September 2026, 2 weeks ago

Recent advances have uncovered a new class of selection rules in particle physics models arising from non-invertible fusion algebras. We refer to these as non-invertible selection rules (NISRs), distinguishing them from conventional selection rules derived from ordinary group laws. In this talk, we illustrate their implications in perturbation theory using spurion analysis, and connect to aspects of "loop-induced groupification" and particle decoupling in effective field theories. The discussion is based on arXiv 2510.18972, 2508.14970, 2503.19964.

Ling-Xiao Xu (ICTP)

===

Find this and many more scientific videos on carmin.tv - a French video platform for mathematics and their interactions with other sciences offering extra functionalities tailored to meet the needs of the research community.

===

Ling-Xiao Xu - Spurion Analysis for a Class of Selection Rules Without Group Actions

$Pierre Schapira - Sheaves for spacetimes A causal manifold $(M,lambda)$ is a real manifold $M$ endowed with a closed convex proper cone $lambda$ in its cotangent bundle $T^*M$. On such a manifold, one defines the $lambda$-topology and the past or the future of any subset. A time function is a smooth surjective causal map $q: Mtomathbb R$ proper on the past or future of any compact subset of $M$. Using a time function, we show that if the micro-support of a sheaf $F$ does not intersect $lambdacup-lambda$ outside of the zero-section, then for any Cauchy hypersurface $N_t=q^{-1}(t)$, the restriction morphism $mathrm{R}Gamma(M;F)tomathrm{R}Gamma(N_t;Fvert_{N_t})$ is an isomorphism. As an application, we get that the Cauchy problem is globally well-posed for hyperfunction solutions of hyperbolic systems. Pierre Schapira (Institut de mathématiques Jussieu-Paris Rive Gauche) Find this and many more scientific videos on https://www.carmin.tv/ - a French video platform for mathematics and their interactions with other sciences offering extra functionalities tailored to meet the needs of the research community.$

Yves Benoist - Convolution and Square on Abelian Groups

Bruno Vallette - Explicit formulas for the noncommutative Cartan calculus

Qiaochu Ma - Small Scale Index Theory, Scalar Curvature, and Gromov’s Simplicial Norm

$Hong Wang - Furstenberg Sets Estimates with Application to Restriction Theory A Kakeya set is a compact subset of $mathbb{R}^n$ containing a unit line segment in every direction. More generally, for $0 lt s leq 1$, an $s$-Furstenberg set is a subset $E subset mathbb{R}^n$ such that for every direction there is a unit line segment whose intersection with $E$ has Hausdorff dimension at least $s$. Furstenberg set problems ask for lower bounds on ${rm dim}_H(E)$ in terms of $s$ and $n$. In this talk I will discuss how such dimension estimates arise naturally in Fourier restriction theory via wave packet decompositions. From this perspective it is natural to consider s-dimensional subsets of line segments, rather than whole segments, because waves may concentrate on sparser subsets of tubes. This is based on joint work with Shukun Wu and joint work in progress with Dima Zakharov. Hong Wang (IHES & NYU) Find this and many more scientific videos on https://www.carmin.tv/ - a French video platform for mathematics and their interactions with other sciences offering extra functionalities tailored to meet the needs of the research community.$

Elsa Vennat - Odyssée au cœur de la dent, à la frontière entre biologie et science des (...)

Takeshi Saito - 3/4 Singular Supports in Equal and Mixed Characteristics

Jintian Zhu - A proof of Riemannian positive mass theorem up to dimension 19

$Toshiki Nakashima - Characterization of the Unit Object in Localized Quantum Unipotent Category For the quiver Hecke algebra $R$, let $R$-gmod be the category of finite-dimensional graded $R$-modules, and let $widetilde{Rmbox{-gmod}}$ be the localization of $R$-gmod, called localized quantum unipotent category``. It has been shown that the set of equivalence classes of simple objects up to grading shifts ${rm Irr}(widetilde{Rmbox{-gmod}})$ in $widetilde{Rmbox{-gmod}}$ has a crystal structure, and ${rm Irr}(widetilde{Rmbox{-gmod}})$ is isomorphic to the so-called cellular crystal ${mathbb B}_{bf i}$ by M. Kashiwara and myself. This isomorphism induces a function $varepsilon_i^*$ on ${mathbb B}_{bf i}$. We give an explicit form of $varepsilon_i^*$, and using this, we give a characterization of the unit object of $widetilde{Rmbox{-gmod}}$ for finite classical types, $A_n,,B_n,, C_n$ and $D_n$. This is a joint work with Koh Matsuura. Toshiki Nakashima (Sophia University, Tokyo) Find this and many more scientific videos on https://www.carmin.tv/ - a French video platform for mathematics and their interactions with other sciences offering extra functionalities tailored to meet the needs of the research community.$

Institut des Hautes Etudes Scientifiques (IHES) |

Ling-Xiao Xu - Spurion Analysis for a Class of Selection Rules Without Group Actions