November 10 2026 

Yuuka Kanakubo (RIKEN iTHEMS/LBNL)

Location: Swiatecki Lounge B70 annex - 228 

Time: 4:00pm Pacific Time

Host: Yuuka Kanakubo

[Slide]  [Youtube]

Title: A relativistic von Kármán relation for assessing applicability of hydrodynamics

Abstract:  Relativistic viscous hydrodynamics is a widely used theoretical framework for simulating quark–gluon plasma (QGP) dynamics in relativistic heavy-ion collisions. One open question is how to quantitatively assess the validity of a hydrodynamic description of such a system. In this work, we extract the poles of linear response functions from numerical simulations of hydrodynamics and Boltzmann transport. By comparing these responses as a function of the rescaled wavenumber, we identify the wavenumber range over which hydrodynamics captures the underlying microscopic dynamics. We show that the averaged Knudsen number, ⟨Kn^∗⟩, which we define using the von Kármán relation, serves as a useful measure of the rescaled wavenumber. We find that ⟨Kn^∗⟩ ∼ 1 marks the approximate upper limit of agreement between the linear responses of second-order viscous hydrodynamics and Boltzmann transport.

November 17 2026 

Zhiquan Sun (UC Berkeley)

Location: Room 324, Physics South, UC Berkeley Campus Room MAP 

Time: 4:00pm Pacific Time

Host: Felipe Ortega Gama

[Slide]  [Youtube]

Title: Strongly Coupled Soft Functions

Abstract:  The renormalization of operators built out of Wilson lines that meet at an angle (cusp) involve what is known as the cusp anomalous dimension, a universal object appearing in many processes in QCD due to the divergences from gluonic interactions. In this talk, I will discuss the vacuum expectation value of a pair of cusped Wilson lines separated in the transverse direction. This configuration can be related to a simple observable in heavy quark transverse momentum-dependent (TMD) fragmentation as well as the TMD soft function. I will compute the expectation values of cusped Wilson lines in N=4 super Yang-Mills theory at strong coupling via the AdS/CFT correspondence, an approach complementary to perturbative calculations of the cusp anomalous dimension. I will also discuss the possible generalizations of our setup and results to soft functions in other gauge theories with a holographic dual.

November 24 2026 

Koichiro Yasuda (UCLA)

Location: Room 324, Physics South, UC Berkeley Campus Room MAP 

Time: 4:00pm Pacific Time

Host: Shoto Aoki

[Slide]  [Youtube]

Title: Extracting the low-energy reactor neutrino spectrum from CEvNS data: an application of dark matter direct detection techniques

Abstract: Nuclear reactors are the most intense human-made neutrino sources, yet about 70% of their antineutrinos, those below the 1.8 MeV inverse beta decay threshold, have never been measured because standard detectors are insensitive to them. Coherent elastic neutrino-nucleus scattering (CEvNS), in which a neutrino nudges an entire nucleus, can reach this hidden region. The detector, however, sees only the nuclear recoil, so the neutrino spectrum must be reconstructed by working backward, a task known as unfolding. In this talk, I will introduce these ideas from the basics and present an unfolding method borrowed from dark matter direct searches that needs no hand-tuned regularization parameters. Applying it to mock data for a future cryogenic germanium detector, I will show that it performs comparably to standard techniques.

If time allows, I will mention my outreach activities, including a peer-to-peer multiplayer relativistic shooting game.

January 26 2027 

João Silva (UCLA)

Location: Swiatecki Lounge B70 annex - 228 

Time: 4:00pm Pacific Time

Host: Yuuka Kanakubo

[Slide]  [Youtube]

Title: Energy correlators in QCD matter

Abstract: Energy correlators connect angular distributions of final-state energy to the dynamics of QCD radiation. In heavy-ion collisions, they also carry information about the interaction of high-energy partons with the produced matter and the medium's response to deposited energy. A central question is which properties of QCD matter can be inferred from their angular structure. 

I will introduce a description of high-energy partons propagating and radiating in a QCD background. Motivated by the momentum anisotropies characteristic of the early stages of heavy-ion collisions, I will discuss how anisotropic momentum broadening generates azimuthal structure inside jets. I will show its imprint on energy correlators, focusing on heavy-flavour pairs, which provide cleaner access to the underlying partonic splittings. Turning to higher point correlations, I will examine contributions from medium-induced radiation and medium response, including the challenge of distinguishing their angular imprints. More broadly, I will outline how these observables reflect the mean and fluctuating components of energy flow in QCD matter.

February 09 2027 

Ryan Milton (UC Riverside)

Location: Swiatecki Lounge B70 annex - 228 

Time: 4:00pm Pacific Time

Host: Mateusz Ploskon

[Slide]  [Youtube]

Title: AI-Based Unbinned Unfolding and Inference for Deep Inelastic Scattering

Abstract: Machine learning is transforming experimental analysis in high energy nuclear and particle physics, providing new tools at every stage of a measurement. A prime example is unfolding, which corrects data for detector effects but is traditionally performed in histogram bins one observable at a time. OmniFold is a machine learning method that instead unfolds data without binning and across many observables simultaneously. I will present an extension of this approach to unfold full deep inelastic scattering (DIS) events using data from the H1 experiment at HERA, yielding new measurements of jet cross sections. I will then show its application to unbinned inclusive DIS cross sections on nuclei with the CLAS12 detector at Jefferson Lab, offering new insight into quark behavior within the nuclear medium. Finally, I will use simulation-based inference to extract physics parameters from the unfolded H1 events, directly connecting theory and experiment.