From afreese at jlab.org Wed Nov 12 08:00:00 2025 From: afreese at jlab.org (Adam Freese) Date: Wed, 12 Nov 2025 13:00:00 +0000 Subject: [Theory-seminars] Cake seminar TODAY (Wednesday, November 12) at 1 pm in L102 Message-ID: Greetings everyone, We will be having a cake seminar today in CC L102 at 1:00 pm EST given by Zhite Yu. There will also be cake and cookies. Please find the title and abstract below. Title: Factorization of inclusive hadron production in hadron-hadron collisions Abstract: I present a complete proof of the factorization theorem for inclusive hadron production in hadron-hadron collisions. The key improvement over previous literature is the introduction of an explicit unitarity argument formulated in a covariant gauge, applied consistently to both the collinear and soft sectors. When applied to inclusive hadron production, it reduces the relevant pinch surfaces to those familiar from Drell-Yan factorization. The same technique extends naturally to inclusive hadron production in lepton-lepton and lepton-hadron collisions, thereby demonstrating the universality of fragmentation functions. Zhite will also be leaving Jefferson Lab soon, so let us convene 15-20 minutes before the seminar to say our farewells and express our appreciation. Kind regards, Adam (on behalf of the organizing committee: Adam, Joe and Pia) -------------- next part -------------- An HTML attachment was scrubbed... URL: From pialjp at jlab.org Mon Nov 17 09:29:39 2025 From: pialjp at jlab.org (Pia Jones Petrak) Date: Mon, 17 Nov 2025 09:29:39 -0500 Subject: [Theory-seminars] Theory Seminar TODAY IN-PERSON Message-ID: <83b7837e-b9ab-4f27-9abb-821136bc98a7@jlab.org> Hey everyone, We will?be having an *in-person* Theory seminar *today at 1pm**in L102 *(or on Zoom). Below is the info* * Zoom: https://jlab-org.zoomgov.com/j/1604596152?pwd=mibAQ8ziTyr1yrngbs2IIobuEyvuWn.1 Speaker:? Pablo Rab?n (Universidad Complutense de Madrid) Title: Model-independent extraction of ?? and ?N resonances from forward dispersion relations Abstract: A precise description of low-energy ?? and ?N interactions is essential for many problems in hadronic physics. For the ?? system, we present new global fits that satisfy dispersive constraints within uncertainties up to 1.6 GeV, while describing all available experimental data up to 1.8 GeV. Using continued-fraction expansions, we extract resonance pole parameters in a model-independent way from forward dispersion relations. For ?N scattering, following a careful revision of the database, we determine resonance parameters from forward dispersion relations using exclusively total cross-section data together with the optical theorem. Best wishes, Adam, Joe, and Pia -- Pia Leonie Jones Petrak Postdoctoral Fellow Theoretical and Computational Physics Center Jefferson Lab -------------- next part -------------- An HTML attachment was scrubbed... URL: From jkarpie at jlab.org Tue Nov 18 12:01:41 2025 From: jkarpie at jlab.org (Joseph Karpie) Date: Tue, 18 Nov 2025 17:01:41 +0000 Subject: [Theory-seminars] Cake Seminar tomorrow Message-ID: Hey everyone, We will be having a double feature Cake Seminar tomorrow. At 1pm we will be hearing talks from Nick Chambers and Yamil Medrano Cahuana. Please join us in F224-225. Nick Chambers: Title: Progress in Three-Body Partial-Wave Formalism Abstract: Among the many challenges in predicting properties of hadrons from QCD is the modeling of interactions involving three or more particles. Three body effects are critical to studies of exotic hadrons like the Tcc and benchmark resonances like the ?, which have been observed to decay into three-body final states. Resonances like the ? will appear in partial wave projections of 3??3? scattering amplitudes, but recent descriptions of these amplitudes from S-matrix theory are incomplete and rely on an asymmetric choice of basis. I will present a symmetrized form of a 3?3 reaction amplitude that has this unphysical basis dependence removed, and I will demonstrate the validity of our result with a numerical application of our symmetrization procedure to a toy model three-pion process. We visualize this system with Dalitz plots that exhibit the rich symmetry features which are anticipated of three-pion interactions. The Dalitz plots we present are one example of an observable that could be constructed using our symmetrized amplitude to predict features of hadronic interactions from QCD. Yamil Medrano Cahuana: Title: Gaussian Processes for Inferring Parton Distributions Abstract: I will present an overview of my work on solving the inverse problem of reconstructing parton distribution functions from Lattice QCD data within the pseudo-PDF framework. I will outline the links between parametric and non-parametric strategies and explain how Gaussian processes provide flexible Bayesian priors that encode correlations and physical constraints without fixing a functional shape. To evaluate how strongly the data constrain the reconstruction, we quantify information gain through the Kullback?Leibler divergence. Tests on synthetic data confirm the consistency and robustness of the method. These results support Gaussian-process regression as a systematic non-parametric approach to PDF reconstruction, offering controlled uncertainties and reduced model bias in Lattice QCD analyses. -- Joe Karpie Pronouns: He/His/Him Postdoctoral Fellow Theoretical and Computational Physics Center Jefferson Lab -------------- next part -------------- An HTML attachment was scrubbed... URL: